498 Sentences With "spermatozoa" | Random Sentence Generator

On Thursday, French researchers reported that the virus can penetrate individual spermatozoa.

That way, spermatozoa aren't dissolved before even making it out of the dick.

Spermatozoa and blood corpuscles are single cells, and also have little water in them.

In particular, prepubertal patients may suffer from permanent infertility because mature spermatozoa in semen cannot be cryopreserved prior to therapy.

Promiscuity increases the risk that a female will be inseminated by another male before the first male's spermatozoa have had a chance to fertilise the female's eggs.

In Mr. Wiley's "Napoleon," from 2005, the Alpine setting has given way to an abstract ground of red and gold brocade, speckled, strange to say, by swimming spermatozoa.

The subject matter is fitting for the space: an intricate, interwoven array of anthropomorphized penises and monstrous spermatozoa, which climb the walls and swim loop-the-loops around the room's corners.

Carl Strüwe never gained fame during his lifetime, but over the decades his stark images of diatoms, spermatozoa and other life under the microscope have gathered admirers for their distinctive artistry.

I went to see a fertility specialist who told me that despite my less-than-stellar spermatozoa, the field of fertility, as it relates to the mumps, is somewhat of a mystery.

The study, published in The Lancet Infectious Diseases, found the virus in about 4 percent of the spermatozoa of a 32-year-old man who had had Zika symptoms more than four months earlier.

A host of hand-drawn symbols dangling from the ceiling — heavily lashed eyeballs, wriggling spermatozoa, streaks of lightning — were joined in the firmament by tennis balls and rackets, hot water bottles, umbrellas and an inflatable killer whale.

"If humans ever start to live permanently in space, assisted reproductive technology using preserved spermatozoa will be important for producing offspring," the researchers write in their paper published today in Proceedings of the National Academy of Sciences.

This arrogance has, as I see it, two main causes — one, a belief that their spermatozoa are good for a very long time, indeed, and two, a belief that they could get a younger woman if they wanted to.

" Let's talk numbers: One 2011 study found that, in a sample of 27 cis men, 41% had pre-cum that contained spermatozoa, and for the majority of those cases (37% of all the men in the study), "a reasonable proportion of the sperm was motile.

When a female is inseminated with spermatozoa from an allospecific male, his spermatozoa successfully fertilize the eggs.

Sperm cells that are motile are spermatozoa. Spermatozoa are protected from the male's immune system by the blood-testis barrier. However, spermatozoa are deposited into the female in semen, which is mostly the secretions of the seminal vesicles, prostate gland, and bulbourethral glands. In this way antibodies generated by the male are deposited into the female along with spermatozoa.

In the wood mouse (Apodemus sylvaticus), aggregates of spermatozoa form mobile trains, some of the spermatozoa undergo premature acrosome reactions that correlate to improved mobility of the mobile trains towards the female egg for fertilisation. This association is thought to proceed as a result of a "green beard effect" in which the spermatozoa perform a kin-selective altruistic act after identifying genetic similarity with the surrounding spermatozoa.

Globozoospermia is a rare and severe form of monomorphic teratozoospermia. This means that the spermatozoa show the same abnormality, and over 85% of spermatozoa in sperm have this abnormality. Globozoospermia is responsible for less than 0.1% of male infertility. It is characterised by round-headed spermatozoa without acrosomes, an abnormal nuclear membrane and midpiece defects.

When using intracytoplasmic sperm injection (ICSI) for IVF, the implantation rate is higher in oocytes injected with spermatozoa that have undergone acrosome reaction (~40%) vs. those injected with nonreacted spermatozoa (~10%). The implantation rate is ~25% in when injected with both reacted and nonreacted spermatozoa. The delivery rate per cycle follows the same trend.

Opossum spermatozoa exhibit sperm-pairing, forming conjugate pairs in the epididymis. This may ensure that flagella movement can be accurately coordinated for maximal motility. Conjugate pairs dissociate into separate spermatozoa before fertilization.

When human and mouse spermatozoa are exposed to a fluid flow, roughly one half of them (i.e., both capacitated and noncapacitated spermatozoa) reorient and swim against the current. The flow, which is prolactin-triggered oviductal fluid secretion, is generated in female mice within 4 h of sexual stimulation and coitus. Thus, rheotaxis orients spermatozoa towards the fertilization site.

As the X chromosome is larger (i.e. has more DNA) than the Y chromosome, the "female" (X-chromosome bearing) spermatozoa will absorb a greater amount of dye than its male (Y-chromosome bearing) counterpart. As a consequence, when exposed to UV light during flow cytometry, X spermatozoa fluoresce brighter than Y- spermatozoa. As the spermatozoa pass through the flow cytometer in single file, each spermatozoon is encased by a single droplet of fluid and assigned an electric charge corresponding to its chromosome status (e.g.

These develop into mature spermatozoa, also known as sperm cells. Thus, the primary spermatocyte gives rise to two cells, the secondary spermatocytes, and the two secondary spermatocytes by their subdivision produce four spermatozoa and four haploid cells. Spermatozoa are the mature male gametes in many sexually reproducing organisms. Thus, spermatogenesis is the male version of gametogenesis, of which the female equivalent is oogenesis.

J. Reprod. Fertil. 56, 515–520. may assist the spermatozoa to reach there. At this location, the spermatozoa may be chemotactically guided to the oocyte-cumulus complex by the gradient of progesterone, secreted from the cumulus cells.

Occupational exposure to benzene is associated with a 2.8-fold increase of XX disomy and a 2.6-fold increase of YY disomy in spermatozoa. Pesticides are released to the environment in large quantities so that most individuals have some degree of exposure. The insecticides fenvalerate and carbaryl have been reported to increase spermatozoa aneuploidy. Occupational exposure of pesticide factory workers to fenvalerate is associated with increased spermatozoa DNA damage.

As a matter of fact, until not too long ago, the dogma was that, in mammals, guidance of spermatozoa to the oocyte was unnecessary. This was due to the common belief that, following ejaculation into the female genital tract, large numbers of spermatozoa 'race' towards the oocyte and compete to fertilize it. This belief was taken apart when it became clear that only few of the ejaculated spermatozoa — in humans, only ~1 of every million spermatozoa — succeed in entering the oviducts (Fallopian tubes)Eisenbach, M. and Giojalas, L.C. (2006) Sperm guidance in mammals - an unpaved road to the egg. Nat. Rev. Mol.

Mammalian spermatozoa, like sea-urchin spermatozoa, appear to sense the chemoattractant gradient temporally (comparing receptor occupancy over time) rather than spatially (comparing receptor occupancy over space). This is because the establishment of a temporal gradient in the absence of spatial gradient, achieved by mixing human spermatozoa with a chemoattractantGakamsky, A., Armon, L. and Eisenbach, M. (2009) Behavioral response of human spermatozoa to a concentration jump of chemoattractants or intracellular cyclic nucleotides. Hum. Reprod. 24, 1152-1163. or by photorelease of a chemoattractant from its caged compound,Armon, L. and Eisenbach, M. (2011) Behavioral mechanism during human sperm chemotaxis: Involvement of hyperactivation.

Spermatozoa, in this case human, are a primary component in normal semen, and the agents of fertilization of female ova. Semen, also known as seminal fluid, is an organic fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. In humans, seminal fluid contains several components besides spermatozoa: proteolytic and other enzymes as well as fructose are elements of seminal fluid which promote the survival of spermatozoa, and provide a medium through which they can move or "swim".

CAD protein has been observed in the mid-piece of mammalian spermatozoa, among the mitochondria.

To explore the dimensional attributes of haploid and disomic X-bearing and Y-bearing spermatozoa.

Laparoscopic insemination technique with low numbers of spermatozoa in superovulated prepuberal gilts for biotechnological application.

Expl" Cell Res 1987; 171 , pp. 505–508R. Jones. Interaction of zona pellucida glycoproteins, sulphated carbohydrates and synthetic polymers with proacrosin, the putative egg-binding protein from mammalian spermatozoa" Development 1991; 111 , pp. 1155–1163 Under the secondary binding protein hypothesis, acrosin could serve a role in binding to molecules on the zona pellucida, tethering the spermatozoa to the egg. This "tethering" would ensure penetration due to the applied motile force of the spermatozoa.

Prior to flow cytometric sorting, semen is labeled with a fluorescent dye called Hoechst 33342 which binds to the DNA of each spermatozoon. As the X chromosome is larger (i.e. has more DNA) than the Y chromosome, the "female" (X-chromosome bearing) spermatozoa will absorb a greater amount of dye than its male (Y-chromosome bearing) counterpart. As a consequence, when exposed to UV light during flow cytometry, X spermatozoa fluoresce brighter than Y- spermatozoa.

Thus, the single spermatozoa is about 130 μm long overall, with a diameter of 0.7 μm, which becomes narrower near the tail area, reaching 0.2 μm. The sperm is arranged into an agglomeration of around 340-350 individual spermatozoa that create a torch-like shape. The cup part is made up of acrosomes and nucleus, while the handle is made up by the tails. The spermatozoa in the package are held together by fibrils.

The mature spermatozoa are released from the protective Sertoli cells into the lumen of the seminiferous tubule and a process called spermiation then takes place, which removes the remaining unnecessary cytoplasm and organelles. The resulting spermatozoa are now mature but lack motility, rendering them sterile. The non-motile spermatozoa are transported to the epididymis in testicular fluid secreted by the Sertoli cells, with the aid of peristaltic contraction. Whilst in the epididymis, they acquire motility.

Prior to flow cytometric sorting, semen is labeled with a fluorescent dye called Hoechst 33342 which binds to the DNA of each spermatozoon. As the X chromosome is larger (i.e. has more DNA) than the Y chromosome, the "female" (X-chromosome bearing) spermatozoa will absorb a greater amount of dye than its male (Y-chromosome bearing) counterpart. As a consequence, when exposed to UV light during flow cytometry, X spermatozoa fluoresce brighter than Y- spermatozoa.

During the maturation phase of spermiogenesis, the Sertoli cells consume the unneeded portions of the spermatozoa.

As such, it can guide spermatozoa for short distances only, estimated at the order of millimeters.

Numerous studies have detailed that in ADAM3 null mice, the spermatozoa fail to migrate through the utero-tubal junction. Furthermore, knockout of the closely related ADAM1a gene in mice, an estrogen receptor not found in mature spermatozoa, causes loss of surface ADAM3 and decreased zona pellucida binding. Other studies have shown ADAM3-/- mouse spermatozoa fail to show sperm-sperm aggregation, although the significance of this is still unknown. ADAM3 has not yet been found in humans.

The response of spermatozoa to temporal temperature changes even when the temperature is kept constant spatially suggests that, as in the case of human sperm chemotaxis,Gakamsky, A., Armon, L. and Eisenbach, M. (2009) Behavioral response of human spermatozoa to a concentration jump of chemoattractants or intracellular cyclic nucleotides. Hum. Reprod. 24, 1152-1163. sperm thermotaxis involves temporal gradient sensing. In other words, spermatozoa apparently compare the temperature (or a temperature-dependent function) between consecutive time points.

Exposure of males to certain lifestyle, environmental and/or occupational hazards may increase the risk of aneuploid spermatozoa. In particular, risk of aneuploidy is increased by tobacco smoking, and occupational exposure to benzene, insecticides, and perfluorinated compounds. Increased aneuploidy is often associated with increased DNA damage in spermatozoa.

Exposure of male to certain lifestyle, environmental and/or occupational hazards may increase the risk of aneuploid spermatozoa. In particular, risk of aneuploidy is increased by tobacco smoking, and occupational exposure to benzene, insecticides, and perfluorinated compounds. Increased aneuploidy is often associated with increased DNA damage in spermatozoa.

The insecticides fenvalerate and carbaryl have been reported to increase spermatozoa aneuploidy. Occupational exposure of pesticide factory workers to fenvalerate is associated with increased spermatozoa DNA damage. Exposure to fenvalerate raised sex chromosome disomy 1.9-fold and disomy of chromosome 18 by 2.6-fold (Xia et al., 2004).

Exposure of males to lifestyle, environmental and/or occupational hazards may increase the risk of spermatozoa aneuploidy. Tobacco smoke contains chemicals that cause DNA damage. Smoking also can induce aneuploidy. For instance, smoking increases chromosome 13 disomy in spermatozoa by 3-fold, and YY disomy by 2-fold.

The response of spermatozoa to temporal temperature changes even when the temperature is kept constant spatially suggests that, as in the case of human sperm chemotaxis, sperm thermotaxis involves temporal gradient sensing. In other words, spermatozoa apparently compare the temperature (or a temperature- dependent function) between consecutive time points. This, however, does not exclude the occurrence of spatial temperature sensing in addition to temporal sensing. Human spermatozoa can respond thermotactically within a wide temperature range (at least 29–41 °C).

In 2012, mature spermatozoa capable of fertilization was isolated from in vitro culture of immature mouse testis tissue.

Factors regulating changes of head-to-head agglutinability in boar spermatozoa during epididymal transit and capacitation in vitro.

Evidence exists that illustrates the ability of genetically similar spermatozoa to cooperate so as to ensure the survival of their counterparts thereby ensuring the implementation of their genotypes towards fertilization. Cooperation confers a competitive advantage by several means, some of these include incapacitation of other competing sperm and aggregation of genetically similar spermatozoa into structures that promote effective navigation of the female reproductive tract and hence improve fertilization ability. Such characteristics lead to morphological adaptations that suit the purposes of cooperative methods during competition. For example, spermatozoa possessed by the wood mouse (Apodemus sylvaticus) possess an apical hook which is used to attach to other spermatozoa to form mobile trains that enhance motility through the female reproductive tract.

Cell Biol. 7, 276–285. and when more recent studies showed that mammalian spermatozoa do respond chemotactically.Ralt, D., Manor, M., Cohen-Dayag, A., Tur-Kaspa, I., Makler, A., Yuli, I., Dor, J., Blumberg, S., Mashiach, S. and Eisenbach, M. (1994) Chemotaxis and chemokinesis of human spermatozoa to follicular factors. Biol. Reprod.

Exposure of spermatozoa to oxidative stress is a major causative agent of male infertility. Sperm DNA fragmentation, caused by oxidative stress, appears to be an important factor in the etiology of male infertility. A high level of the oxidative DNA damage 8-OHdG is associated with abnormal spermatozoa and male infertility.

When mature, the spermatozoa of S. seticornis show five lateral arms, similar to the sperm morphology of Inachus phalangium.

The opposite happens in response to an increase in temperature. This suggests that when capacitated spermatozoa swim up a temperature gradient, turns are repressed and the spermatozoa continue swimming in the gradient direction. When they happen to swim down the gradient, they turn again and again until their swimming direction is again up the gradient.

The male accessory glands are the ampullary gland, seminal vesicles, prostate, bulbourethral gland, and urethral glands. The products of these glands serve to nourish and activate the spermatozoa, to clear the urethral tract prior to ejaculation, serve as the vehicle of transport of the spermatozoa in the female tract, and to plug the female tract after placement of spermatozoa to help ensure fertilization. Although the glands are usually described as being branched tubular or branched tubuloalveolar, they vary in their organization and in their distribution in different species.

17, 628-632 It is, therefore, believed that, in mammals, sperm chemotaxis occurs in the oviduct, close to the oocyte. First spermatozoa may be chemotactically guided to the oocyte-cumulus complex by the gradient of progesterone, secreted from the cumulus cells. In addition, progesterone may inwardly guide spermatozoa, already present within the periphery of the cumulus oophorus. Spermatozoa that are already deep within the cumulus oophorus may sense the more potent chemoattractant that is secreted from the oocyte and chemotactically guide themselves to the oocyte according to the gradient of this chemoattractant.

For purposes of in vitro fertilization, capacitation occurs by incubating spermatozoa that have either undergone ejaculation or have been extracted from the epididymis and incubated in a defined medium for several hours. There are different techniques to perform the capacitation step: simple washing, migration (swim-up), density gradients, and filter. The objective is to isolate as many motile spermatozoa as possible and to eliminate non-motile or dead spermatozoa. After either in vivo or in vitro capacitation the sperm must undergo the final maturation step, activation, involving the acrosome reaction.

Spermatozoa do not reach full motility until they reach the vagina, where the alkaline pH is neutralized by acidic vaginal fluids.

Other aspects of the biology of this species have been well- studied, from the production and morphologyTeixeira, R.D., et al. (1999). Ultrastructural study of the spermatozoa of the Neotropical lizards, Tropidurus semitaeniatus and Tropidurus torquatus (Squamata, Tropiduridae). Tissue & Cell 31 (3): 308-317. of its spermatozoa, to the histology of its liver,Firmiano, E.M.S., et al. (2011).

Sperm DNA fragmentation appears to be an important factor in the aetiology of male infertility, since men with high DNA fragmentation levels have significantly lower odds of conceiving. Oxidative stress is the major cause of DNA fragmentation in spermatozoa. A high level of the oxidative DNA damage 8-OHdG is associated with abnormal spermatozoa and male infertility.

Exposure of male workers to carbaryl increased DNA fragmentation in spermatozoa, and also increased sex chromosome disomy by 1.7-fold and chromosome 18 disomy by 2.2-fold. Humans are exposed to perfluorinated compounds (PFCs) in many commercial products. Men contaminated with PFCs in whole blood or seminal plasma have spermatozoa with increased levels of DNA fragmentation and chromosomal aneuploidies.

A. florea queens typically mate with 3-4 males. A. florea mate with fewer drones than A. mellifera. A. mellifera queens mate with as many as 25 drones and simply deposit spermatozoa in the oviducts of the queen, where only 10% of spermatozoa reach the spermatheca. Thus, A. florea use the more energetically efficient method of sperm transfer.

23, 443-452. to the current (rather than to the temperature gradient per se). Another concern was that the temperature could have changed the local pH of the buffer solution in which the spermatozoa are suspended. This could generate a pH gradient along the temperature gradient, and the spermatozoa might have responded to the formed pH gradient by chemotaxis.

683 (1928), p. 491. Andry confirms an argument previously made by Leeuwenhoek, that spermatozoa are "the occasion of the Generation of all Animals." Though Andry recognizes the importance of sperm to reproduction, however, he addresses their workings primarily in the context of parasitology, and essentially considers spermatozoa to be a unique species of parasitic worm.Punnet, 493-94.

The gonads of the C. annaskala have been described as folded into a ribbon in a genital band. The stretched out gonadial ribbon reached 300 mm. Epithelial cavities will make chambers which fuse to become a genital sinus. Spermatozoa are formed in follicles which stay connected to the genital sinus, providing a conduit for the spermatozoa to travel.

Depending on the species, spermatozoa can fertilize ova externally or internally. In external fertilization, the spermatozoa fertilize the ova directly, outside of the female's sexual organs. Female fish, for example, spawn ova into their aquatic environment, where they are fertilized by the semen of the male fish. During internal fertilization, however, fertilization occurs inside the female's sexual organs.

One SSC is the precursor for multiple spermatozoa and therefore SSCs are much less numerous in the testes than cells undergoing spermatogenesis.

During copulation, the cirri of one individual connect with those of the other through the genital pore, and then spermatozoa are exchanged.

Non-mammalian spermatozoa do not require this capacitation step and are ready to fertilize an oocyte immediately after release from the male.

70, 93-117. As a matter of fact, until not too long ago, the dogma was that, in mammals, guidance of spermatozoa to the oocyte was unnecessary. This was due to the common belief that, following ejaculation into the female genital tract, large numbers of spermatozoa 'race' towards the oocyte and compete to fertilize it. Research during the 1980s"Professor Michael Eisenbach of the Weizmann Membrane Reearch Department was inspired to initiate this research several years ago when ..." caused this belief to be taken apart when it became clear that only few of the ejaculated spermatozoa — in humans, only ~1 of every million spermatozoa — succeed in entering the oviducts (Fallopian tubes)Eisenbach, M. and Giojalas, L.C. (2006) Sperm guidance in mammals - an unpaved road to the egg. Nat. Rev. Mol.

It plays a fundamental role in the development of the brain and retina as well as in the formation and motility of spermatozoa.

A method to increase the chance of pregnancy is ICSI. The percentage of viable spermatozoa in complete asthenozoospermia varies between 0 and 100%.

Reproductive system of a bovine female Ox testes On farms it is very common to use artificial insemination (AI), a medically assisted reproduction technique consisting of the artificial deposition of semen in the female's genital tract. It is used in cases where the spermatozoa can not reach the fallopian tubes or simply by choice of the owner of the animal. It consists of transferring, to the uterine cavity, spermatozoa previously collected and processed, with the selection of morphologically more normal and mobile spermatozoa. A cow's udder contains two pairs of mammary glands, (commonly referred to as teats) creating four "quarters".

PLOS One 6, e28359. results in delayed transient changes in swimming behavior that involve increased frequency of turns and hyperactivation events. On the basis of these observations and the finding that the level of hyperactivation events is reduced when chemotactically responsive spermatozoa swim in a spatial chemoattractant gradient it was proposed that turns and hyperactivation events are suppressed when capacitated spermatozoa swim up a chemoattractant gradient, and vice versa when they swim down a gradient. In other words, human spermatozoa approach chemoattractants by modulating the frequency of turns and hyperactivation events, similarly to Escherichia coli bacteria.

It was proposed that capacitated spermatozoa might detach from the oviductal surface faster than non-capacitated spermatozoa, enabling them to swim into the main current. To understand the mechanism of sperm turning in rheotaxis, quantitative analysis of human sperm flagellar behavior during rheotaxis turning was carried out. The results revealed, both at the single cell and population levels, that there is no significant difference in flagellar beating between rheotaxis turning spermatozoa and free-swimming spermatozoa.Zhang, Z., Liu, J., Meriano, J., Ru, C., Xie, S., Luo, J., and Sun, Y. (2016) Human sperm rheotaxis: a passive physical process. Sci. Rep.

PLOS One 6, e28359. results in delayed transient changes in swimming behavior that involve increased frequency of turns and hyperactivation events. On the basis of these observations and the finding that the level of hyperactivation events is reduced when chemotactically responsive spermatozoa swim in a spatial chemoattractant gradient it was proposed that turns and hyperactivation events are suppressed when capacitated spermatozoa swim up a chemoattractant gradient, and vice versa when they swim down a gradient. In other words, human spermatozoa approach chemoattractants by modulating the frequency of turns and hyperactivation events, similarly to Escherichia coli bacteria.

The sperm cells having least DNA damage may subsequently be injected into the egg cell by intracytoplasmic sperm injection (ICSI). Many other methods for sperm sorting have been proposed or are currently tested. To select spermatozoa with low DNA damage index the population of sperm could be enriched with spermatozoa with non-fragmented DNA, with techniques like electrophoresis, Z method and MACS (Magnetic Activating Cell Sorting), which in combination with density gradient centrifugation in single sperm preparation protocols results in spermatozoa with superior quality. Hyaluronic acid (HA) binding sites on the sperm plasma membrane are an indicator of sperm maturity (Huszar et al.

Journal of the World Aquaculture Society. Vol. 40. No. 3. Morphologic changes in reproductive periods include females changes in gonad colour and oocyte numbers, while in males there is an increase in the amount of spermatozoa in particular zones described as "wet mounts of 'mashed' gonad tissue". Furthermore, there is an increase in spermatozoa in the lumen of histological sections.

The male's main reproductive function is to produce and store spermatozoa and provide transport to the reproductive tract of the female. Sperm development is usually completed by the time the insect reaches adulthood. The male has two testes, which contain follicles in which the spermatozoa are produced. These open separately into the sperm duct or vas deferens and this stores the sperm.

Micrograph of a spermatocele. The characteristic sperm are present (black dots - left of image). H&E; stain.Dilated rete testis containing spermatozoa within cyst lumen.

Nocardiopsis exhalans is a species of bacteria. It produces methanol-soluble toxins that paralyse the motility of boar spermatozoa. Its type strain is ES10.1T.

Dott H.M. & Skinner J.D. (1967). A reassessment of extragonadal spermatozoa reserves in Suffolk rams. Journal of Agricultural Sciences 69: 293-295.Orgebin-Crist M.C. (1968).

Nocardiopsis umidischolae is a species of bacteria. It produces methanol- soluble toxins that paralyse the motility of boar spermatozoa. Its type strain is 66/93T.

Symsagittifera roscoffensis also has a muscular system consisting of a complex network of transversal, longitudinal, circular and dorsal-ventral muscle fibers. This worm is hermaphrodite but does not self-fertilize: it must mate with a partner to reproduce. Mature spermatozoa are produced at the posterior end of the animal. The oocytes are fertilized by the spermatozoa of the partners who are stored, after mating, in a spermatheca.

Capacitated human spermatozoa swim in rather straight lines interrupted by turns and brief episodes of hyperactivation. Each such episode results in swimming in a new direction. When the spermatozoa sense a decrease in temperature, the frequency of turns and hyperactivation events increases due to increased flagellar-wave amplitude that results in enhanced side-to-side head displacement. With time, this response undergoes partial adaptation.

In addition, progesterone may inwardly guide spermatozoa, already present within the periphery of the cumulus oophorus. Spermatozoa that are already deep within the cumulus oophorus may sense the more potent chemoattractant that is secreted from the oocyte and chemotactically guide themselves to the oocyte according to the gradient of this chemoattractant. It should be borne in mind, however, that this is only a model. right Figure 2.

Smoking also can induce aneuploidy. For instance, smoking increases chromosome 13 disomy in spermatozoa by 3-fold and YY disomy by 2-fold. Occupational exposure to benzene is associated with a 2.8-fold increase of XX disomy and a 2.6-fold increase of YY disomy in spermatozoa. Pesticides are released to the environment in large quantities so that most individuals have some degree of exposure.

Spermatozoa develop in the seminiferous tubules of the testes. During their development the spermatogonia proceed through meiosis to become spermatozoa. Many changes occur during this process: the DNA in nuclei becomes condensed; the acrosome develops as a structure close to the nucleus. The acrosome is derived from the Golgi apparatus and contains hydrolytic enzymes important for fusion of the spermatozoon with an egg cell.

Selenoprotein P transports the trace element selenium from the liver to the testes and brain, and binds to ApoER2 in these areas. ApoER2 functions to internalize this complex to maintain normal levels of selenium in these cells. Selenium is necessary in the testes for proper spermatozoa development. Mice that have had their ApoER2 or Selenoprotein P expression knocked out show impaired spermatozoa development and decreased fertility.

Capacitated human spermatozoa swim in rather straight lines interrupted by turns and brief episodes of hyperactivation. Each such episode results in swimming in a new direction. When the spermatozoa sense a decrease in temperature, the frequency of turns and hyperactivation events increases due to increased flagellar-wave amplitude that results in enhanced side-to-side head displacement. With time, this response undergoes partial adaptation.

Semenogelin-2 is a protein that in humans is encoded by the SEMG2 gene. The secreted protein encoded by this gene is involved in the formation of a gel matrix that encases ejaculated spermatozoa. Proteolysis by the prostate- specific antigen (PSA) breaks down the gel matrix and allows the spermatozoa to move more freely. The encoded protein is found in lesser abundance than a similar semenogelin protein.

The queen will store the spermatozoa, returning to the nest to lay her eggs which she fertilizes in the laying process with remarkably few sperm per egg.

During foetal development, gonocytes develop from primordial germ cells and following this SSCs develop from gonocytes in the testis. SSCs are the early precursor for spermatozoa and are responsible for the continuation of spermatogenesis in adult mammals. The stem cells are capable of dividing into more SSCs which is vital for maintaining the stem cell pool. Alternatively, they go on to differentiate into spermatocytes, spermatids and finally spermatozoa.

Semenogelin is a protein that is involved in the formation of a gel matrix that encases ejaculated spermatozoa, preventing capacitation. It blocks capacitation mainly via inhibition of reactive oxygen species (ROS) generation. Proteolysis by prostate-specific antigen (PSA) breaks down the gel matrix and allows the spermatozoa to move more freely.Entrez Gene: SEMG2 semenogelin II The cleavage products of the semenogelins constitute the main antibacterial components in human seminal plasma.

Spermatogenesis starts in the bottom part of seminiferous tubes and, progressively, cells go deeper into tubes and moving along it until mature spermatozoa reaches the lumen, where mature spermatozoa are deposited. The division happens asynchronically; if the tube is cut transversally one could observe different maturation states. A group of cells with different maturation states that are being generated at the same time is called a spermatogenic wave.

Stained human sperm Human spermatozoa Sperm competition is the competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and variety of mates increases a female's chance to produce more viable offspring. However, multiple mates for a female means each individual male has decreased chances of producing offspring.

Propidium iodide staining revealed that only the basal surface of the hook is of nuclear origin. These apical hooks are deployed in female reproductive tract (mechanism responsible involved the remodeling of actin filaments in the hook). Deployed apical hooks combine with apical hooks and flagella of other spermatozoa. The aggregates of spermatozoa that result form "mobile trains", which have experimentally been determined to possess better motility in the female reproductive tract.

The proteolysis process breaks down the gel matrix and allows the spermatozoa to move more freely. Two transcript variants encoding different isoforms have been found for this gene.

J. Exp. Biol. 206(Pt 22), 4155-4166. It has been suggested that capacitated spermatozoa, released from the sperm storage site at the isthmus,Suarez, S.S. (2002) Gamete transport.

Sperm chemotaxis is a form of sperm guidance, in which sperm cells (spermatozoa) follow a concentration gradient of a chemoattractant secreted from the oocyte and thereby reach the oocyte.

2 In order to successfully produce transgenic animals by SMGT, the spermatozoa must attach the exogenous DNA into the head and these transfected spermatozoa must maintain their functionality to fertilize the oocyte.2 Genetically modified animals produced by SMGT are useful for research in biomedical, agricultural, and veterinary fields of study. SMGT could also be useful in generating animals as models for human diseases or lead to future discoveries relating to human gene therapy.

Often in insects the vulva is narrow and the genital chamber becomes pouch or tube like and is called the vagina. Related to the vagina is a saclike structure, the spermatheca, where spermatozoa are stored ready for egg fertilisation. A secretory gland nourishes the contained spermatozoa in the vagina. Egg development is mostly completed by the insect's adult stage and is controlled by hormones that control the initial stages of oogenesis and yolk deposition.

As the spermatozoa pass through the flow cytometer in single file, each spermatozoon is encased by a single droplet of fluid and assigned an electric charge corresponding to its chromosome status (e.g. X-positive charge, Y-negative charge). The stream of X- and Y- droplets is then separated by means of electrostatic deflection and collected into separate collection tubes for subsequent processing.Seidel GE, Jr., Garner DL. Current status of sexing mammalian spermatozoa.

D.P. Green. The head shapes of some mammalian spermatozoa and their possible relationship to the shape of the penetration slit through the zona pellucida. J. Reprod. Fertil., 83 (1988), pp.

Progesterone receptor membrane component 2 (abbreviated PGRMC2) is a protein which is encoded by the PGRMC2 gene. It has been detected in the placenta, liver, and spermatozoa, among other areas.

The mobility of these mobile trains was also found to be influenced by premature acrosome reactions, altruistic acts performed by some spermatozoa for the benefit of other genetically similar gametocytes. This altruism follows a "green beard" mechanism in which spermatozoa discern the genetic similarity of surrounding gametocytes (such mechanisms are rare because they must code for a recognizable phenotype, as well as response mechanisms). Once spermatozoa of similar genotypes are identified, altruism genes are turned on to elicit a response that seeks to conserve the genes present in the other cell, even if it results in the destruction of the cell performing the action. The gestation period of wood mice is of 25–26 days and each female produces on average five young.

Following the findings that human spermatozoa accumulate in follicular fluidRalt, D., Goldenberg, M., Fetterolf, P., Thompson, D., Dor, J., Mashiach, S., Garbers, D.L. and Eisenbach, M. (1991) Sperm attraction to a follicular factor(s) correlates with human egg fertilizability. Proc. Natl. Acad. Sci. U.S.A. 88, 2840–2844.Villanueva-Díaz, C., Vadillo-Ortega, F., Kably-Ambe, A., Diaz-Perez, M.A. and Krivitzky, S.K. (1990) Evidence that human follicular fluid contains a chemoattractant for spermatozoa. Fertil. Steril. 54, 1180–1182.

Exposure to fenvalerate raised sex chromosome disomy 1.9-fold and disomy of chromosome 18 by 2.6-fold. Exposure of male workers to carbaryl increased DNA fragmentation in spermatozoa, and also increased sex chromosome disomy by 1.7-fold and chromosome 18 disomy by 2.2-fold. Humans are exposed to perfluorinated compounds (PFCs) in many commercial products. Men contaminated with PFCs in whole blood or seminal plasma have spermatozoa with increased levels of DNA fragmentation and chromosomal aneuploidies.

Capacitation is the penultimate step in the maturation of mammalian spermatozoa and is required to render them competent to fertilize an oocyte. This step is a biochemical event; the sperm move normally and look mature prior to capacitation. In vivo, capacitation occurs after ejaculation, when the spermatozoa leave the vagina and enter the superior female reproductive tract. The uterus aids in the steps of capacitation by secreting sterol- binding albumin, lipoproteins, and proteolytic and glycosidasic enzymes such as heparin.

When pAGSs develop into AGSs, ovigerous tissue is also completely replaced by seminiferous lobules. However, the ovarian lumen remains even after the sex change, functioning as a common spermatozoa collection region that is continuous with the common genital sinus as free spermatozoa travels from seminiferous lobules into the gonadal lumen. Gonochorism refers to development or evolution of sex. Gonochoric goby species normally do not possess pAGSs, but pAGSs are observed in E. illecebrosus and E. evelynae.

It has been observed in locusts, that the nervous system initiates female reproductive muscular contractions. In some species, such as R. prolixus, the contractions that move spermatozoa into sperm storage are initiated by a male secretion in the ejaculate. Male secretions, such as the glycoprotein ACP36D in Drosophila, can also play a role in preparing the female reproductive system for sperm storage. It causes changes in uterine shape allowing spermatozoa access to the sperm storage organs.

As well as bring expressed in the olfactory epithelium of the human nose, OR1D2 is special in that it is also expressed in human spermatozoa, where it is involved in sperm chemotaxis.

Pudoc, Wageningen, p. 81\. Secombes, C.J., Lewis, A.E., Laird, L.M., Needham, E.A. and Priede, I.G. (1984). Agglutination of spermatozoa by autoantibodies in the rainbow trout (Salmo gairdneri). J. Fish Biology 25: 691-696.

For example, claudin 11 has been shown to be a necessary component of these tight junctions as mice lacking this gene have a defective blood testis barrier and do not produce mature spermatozoa.

It is estimated that, over the past generation, tens of millions of female foetuses have been aborted. Since the 1990s, some areas have seen up to 25 per cent more male births than female births. Sperm sorting utilizes the technique of flow cytometry to analyze and 'sort' spermatozoa. During the early to mid-1980s, Dr. Glenn Spaulding was the first to sort viable whole human and animal spermatozoa using a flow cytometer, and utilized the sorted motile rabbit sperm for artificial insemination.

Because of this and the extensive travel in the female reproductive tract, spermatozoa are susceptible to anti-sperm antibodies generated by the male in addition to waiting anti- sperm antibodies generated by the female.

However, researchers have tried to determine the age in various populations by taking urine samples of boys and determining the presence of spermatozoa. The presence of sperm in urine is referred to as spermaturia.

A reassessment of extra-gonadal spermatozoa reserves in Suffolk rams. Journal of Agricultural Sciences 69: 293-295.Orgebin-Crist, M.C. (1968). Gonadal and epididymal sperm reserves in the rabbit; Estimation of the daily sperm production.

This invention consists of a sterile, disposable, compartmentalized swim-up column for the swimming-up of spermatozoa (developed by Prof. Zavos), at desired levels of dilution in a suitable media, and a swimming down of spermatozoa into compartments within the column. This device allows for the separation of semen samples in relation to sperm morphology, motility, progressive motility, speed, sperm concentration, fertilisation potential, and sex ratio. The device comprises a hollow, vertically supported column, having a closed lower end, and an open upper end.

Domestic fowl has previously been researched on and it was found that by over feeding but not force feeding the male birds, there was no effect on fertility. However, more recently a study has shown that obesity induced by force feeding can affect the number of spermatozoa and their motility in the male birds. It was also found that in two of the three birds, there was an decrease in testosterone and an increase in LH which suggests the pathway of why there might be reduced spermatozoa.

Cell Biol. 7, 276–285. and when more recent studies showed that mammalian spermatozoa employ at least three different mechanisms, each of which can potentially serve as a guidance mechanism:Pérez-Cerezales, S., Boryshpolets, S. and Eisenbach, M. (2015) Behavioral mechanisms of mammalian sperm guidance. Asian J. Androl. 17, 628-632 chemotaxis,Ralt, D., Manor, M., Cohen-Dayag, A., Tur-Kaspa, I., Makler, A., Yuli, I., Dor, J., Blumberg, S., Mashiach, S. and Eisenbach, M. (1994) Chemotaxis and chemokinesis of human spermatozoa to follicular factors. Biol. Reprod.

Another concern was that the temperature could have changed the local pH of the buffer solution in which the spermatozoa are suspended. This could generate a pH gradient along the temperature gradient, and the spermatozoa might have responded to the formed pH gradient by chemotaxis. However, careful experimental examinations of all these possibilities with proper controls demonstrated that the measured responses to temperature are true thermotactic responses and that they are not a reflection of any other temperature- sensitive process, including rheotaxis and chemotaxis.

Experiments are undergoing to test the effectiveness of an immunocontraceptive vaccine that inhibits the fusing of spermatozoa to the zona pellucida. This vaccine is currently being tested in animals and hopefully will be an effective contraceptive for humans. Normally, spermatozoa fuse with the zona pellucida surrounding the mature oocyte; the resulting acrosome reaction breaks down the egg's tough coating so that the sperm can fertilize the ovum. The mechanism of the vaccine is injection with cloned ZP cDNA, therefore this vaccine is a DNA based vaccine.

The vas deferens, which is also known as the sperm duct, is a thin tube approximately long that starts from the epididymis to the pelvic cavity. It carries the spermatozoa from the epididymis to ejaculatory duct.

In D. T. J. Littlewood & R. A. Bray (Eds.), Interrelationships of the Platyhelminthes (pp. 92-102). London & New York: Taylor and Francis molecules or spermatozoa suggest that the Hexabothriidae are a basal group within the Polyopisthocotylea.

The ultrastructure of epididymal spermatozoa has been studied for A. alba. Mature spermatozoa are filiform and are characterized by features such as a depression in the transverse section of the acrosome, a moderately long midpiece, columnar mitochondria, an elongated nucleus, and a fibrous sheath in the midpiece. Epidermal glands are located in the cloacal region of A. alba and are most likely used for reproduction and marking territory. The openings of the glands are plugged with a solid, holocrine secretion that is removed when it moves through tunnels and leaves a secretion trail.

In vitro spermatogenesis is the process of creating male gametes (spermatozoa) outside of the body in a culture system. The process could be useful for fertility preservation, infertility treatment and may further develop the understanding of spermatogenesis at the cellular and molecular level. Spermatogenesis is a highly complex process and artificially rebuilding it in vitro is challenging. These include creating a similar microenvironment to that of the testis as well as supporting endocrine and paracrine signalling, and ensuring survival of the somatic and germ cells from spermatogonial stem cells (SSCs) to mature spermatozoa.

In the testes of some species of Siluriformes, organs and structures such as a spermatogenic cranial region and a secretory caudal region are observed, in addition to the presence of seminal vesicles in the caudal region. The total number of fringes and their length are different in the caudal and cranial portions between species. Fringes of the caudal region may present tubules, in which the lumen is filled by secretion and spermatozoa. Spermatocysts are formed from cytoplasmic extensions of Sertoli cells; the release of spermatozoa is allowed by breaking of the cyst walls.

Species specificity was not detected in experiments that compared the chemotactic responsiveness of human and rabbit spermatozoa to follicular fluids or egg-conditioned media obtained from human, bovine, and rabbit.Sun, F., Giojalas, L.C., Rovasio, R.A., Tur-Kaspa, I., Sanchez, R. and Eisenbach, M. (2003) Lack of species-specificity in mammalian sperm chemotaxis. Dev. Biol. 255, 423–427. The subsequent findings that cumulus cells of both human and rabbit (and, probably, of other mammals as well) secrete the chemoattractant progesterone is sufficient to account for the lack of specificity in the chemotactic response of mammalian spermatozoa.

The realization that sperm chemotaxis can guide spermatozoa for short distances only, triggered a search for potential long-range guidance mechanisms. The findings that, at least in rabbits and pigs, a temperature difference exists within the oviduct, and that this temperature difference is established at ovulation in rabbits due to a temperature drop in the oviduct near the junction with the uterus, creating a temperature gradient between the sperm storage site and the fertilization site in the oviduct, led to a study of whether mammalian spermatozoa can respond to a temperature gradient by thermotaxis.

One involved a Zigmond chamber, modified to make the temperature in each well separately controllable and measurable. A linear temperature gradient was established between the wells and the swimming of spermatozoa in this gradient was analyzed. A small fraction of the spermatozoa (at the order of ~10%), shown to be the capacitated cells, biased their swimming direction according to the gradient, moving towards the warmer temperature. The other method involved twoBahat, A. and Eisenbach, M. (2010) Human sperm thermotaxis is mediated by phospholipase C and inositol trisphosphate receptor Ca2+ channel. Biol. Reprod.

Species specificity was not detected in experiments that compared the chemotactic responsiveness of human and rabbit spermatozoa to follicular fluids or egg-conditioned media obtained from human, bovine, and rabbit.Sun, F., Giojalas, L.C., Rovasio, R.A., Tur-Kaspa, I., Sanchez, R. and Eisenbach, M. (2003) Lack of species- specificity in mammalian sperm chemotaxis. Dev. Biol. 255, 423–427. The subsequent findings that cumulus cells of both human and rabbit (and, probably, of other mammals as well) secrete the chemoattractant progesterone is sufficient to account for the lack of specificity in the chemotactic response of mammalian spermatozoa.

Sperm-mediated gene transfer (SMGT) is a transgenic technique that transfers genes based on the ability of sperm cells to spontaneously bind to and internalize exogenous DNA and transport it into an oocyte during fertilization to produce genetically modified animals.1 Exogenous DNA refers to DNA that originates outside of the organism. Transgenic animals have been obtained using SMGT, but the efficiency of this technique is low. Low efficiency is mainly due to low uptake of exogenous DNA by the spermatozoa, reducing the chances of fertilizing the oocytes with transfected spermatozoa.

These SSCs can either self-renew or commit to differentiating into spermatozoa upon the proliferation of Asingle into Apaired spermatogonia. The 2 cells of Apaired spermatogonia remain attached by intercellular bridges and subsequently divide into Aaligned spermatogonia, which is made up of 4–16 connected cells. Aaligned spermatogonia then undergo meiosis I to form spermatocytes and meiosis II to form spermatids which will mature into spermatozoa. This differentiation occurs along the longitudinal axis of sertoli cells, from the basement membrane to the apical lumen of the seminiferous tubules.

One involved a Zigmond chamber, modified to make the temperature in each well separately controllable and measurable. A linear temperature gradient was established between the wells and the swimming of spermatozoa in this gradient was analyzed. A small fraction of the spermatozoa (at the order of ~10%), shown to be the capacitated cells, biased their swimming direction according to the gradient, moving towards the warmer temperature. The other method involved twoBahat, A. and Eisenbach, M. (2010) Human sperm thermotaxis is mediated by phospholipase C and inositol trisphosphate receptor Ca2+ channel. Biol. Reprod.

One of his most fundamental discoveries, published in Philosophical Transactions in 1843, was that spermatozoa could sometimes be found inside the ovum. The note that Barry published was titled On the Penetration of Spermatozoa into the Interior of the Ovum. This work, carried out with rabbits, influenced Theodor Ludwig Wilhelm Bischoff's theories concerning fertilisation, but it was not until 1876 that Oscar Hertwig, working with sea urchins, described the fusion of sperm and egg to form a new structure. He was President of the Royal Medical Society of Edinburgh in 1836.

Muscle contraction as a means of moving spermatozoa through the reproductive system into and out of the storage structures has been examined in Diptera, Orthoptera, and Lepidoptera as well as in the species Rhodnius prolixus and the boll weevil. In R. prolixus, rhythmic peristaltic contractions of the oviduct cause contractions of the bursa copulatrix and spermatheca movement. This movement of the spermatheca results in spermatozoa migration into the spermathecal duct and into the spermatheca reservoir. In the boll weevil, contractions are also used to move sperm from the spermathecae so they can fertilize the egg.

Fertilization of two different oocytes by two different spermatozoa results in fraternal twins. The mucous membrane of the uterus, termed the functionalis, has reached its maximum size, and so have the endometrial glands, although they are still non- secretory.

Males also have both internal and external genitalia that are responsible for procreation and sexual intercourse. Production of spermatozoa (sperm) is also cyclic, but unlike the female ovulation cycle, the sperm production cycle is constantly producing millions of sperm daily.

Chemotaxis is a short-range guidance mechanism. As such, it can guide spermatozoa for short distances only, estimated at the order of millimeters.Pérez-Cerezales, S., Boryshpolets, S. and Eisenbach, M. (2015) Behavioral mechanisms of mammalian sperm guidance. Asian J. Androl.

Journal of Reproduction and Fertility 15: 15-25.Amann, R.P., Johnson, L., Thompson, D.L. & Pickett, B.W. (1976). Daily spermatozoal production, epididymal spermatozoal reserves and transit time of spermatozoa through the epididymis of the rhesus monkey. Biology of Reproduction 15: 586-592.

Though much less invasive and preserving the anatomy of the ejaculatory ducts, this procedure is probably not completely free of complications either and success rates are unknown. There is a clinical study currently ongoing to examine the success rate of recanalization of the ejaculatory ducts by means of balloon dilation.UK-SH Universitätsklinikum Schleswig-Holstein Usually, affected men have a normal production of spermatozoa in their testicles, so that after spermatozoa were harvested directly from the testes e.g. by TESE, or the seminal vesicles (by needle aspiration) they and their partners are potentially candidates for some treatment options of assisted reproduction e.g.

Mutations in this gene result in abnormal ciliary ultrastructure and function associated with primary ciliary dyskinesia (PCD) and Kartagener syndrome. The DNAi1 gene (axonemal dynein intermediate chain 1 gene 1) is a gene involved in the development of proper respiratory function, motility of spermatozoa, and asymmetrical organization of the viscera during embryogenesis. This gene affects these three very different aspects of development because all three are dependent on proper cilia function. DNAi1 codes for the development of cilia ultrastructure in the upper and lower respiratory tracts, spermatozoa flagellae, and nodal cilia (cilia of the primitive node).

There are two primary differentiation stages, the first of which involves the transformation of As (single) spermatogonia into daughter progeny Apr (paired) spermatogonia, which are predestined to differentiate. These can divide further to create Aal (A-aligned) spermatogonia. The second step involves the production of differentiating A1 spermatogonia from Apr or Aal spermatogonia. These A1 spermatogonia undergo a further five divisions to produce A2, A3, A4, intermediate and type B spermatogonia, which can enter meiosis I. It takes around 64 days to produce mature spermatozoa from differentiating SSCs, and 100 million spermatozoa can be produced each day.

The males then initiate the process of fertilization by contracting their mantle several times to release the spermatozoa. Cephalopods often mate several times, which influences males to mate longer with females that have previously, nearly tripling the number of contractions of the mantle. To ensure the fertilization of the eggs, female cephalopods release a sperm- attracting peptide through the gelatinous layers of the egg to direct the spermatozoa. Female cephalopods lay eggs in clutches; each egg is composed of a protective coat to ensure the safety of the developing embryo when released into the water column.

Importantly, the fraction of capacitated (and, hence, chemotactically responsive) spermatozoa is low (~10% in humans), the life span of the capacitated/chemotactic state is short (1–4 hours in humans), a spermatozoon can be at this state only once in its lifetime, and sperm individuals become capacitated/chemotactic at different time points, resulting in continuous replacement of capacitated/chemotactic cells within the sperm population, i.e., prolonged availability of capacitated cells.Cohen-Dayag, A., Ralt, D., Tur-Kaspa, I., Manor, M., Makler, A., Dor, J., Mashiach, S. and Eisenbach, M. (1994) Sequential acquisition of chemotactic responsiveness by human spermatozoa. Biol. Reprod. 50, 786–790.

A simplified scheme describing the suggested sequence of sperm guidance events in mammals (Michael Eisenbach, Weizmann Institute of Science, 2009) Following the findings that human spermatozoa accumulate in follicular fluidRalt, D., Goldenberg, M., Fetterolf, P., Thompson, D., Dor, J., Mashiach, S., Garbers, D.L. and Eisenbach, M. (1991) Sperm attraction to a follicular factor(s) correlates with human egg fertilizability. Proc. Natl. Acad. Sci. U.S.A. 88, 2840–2844.Villanueva-Díaz, C., Vadillo-Ortega, F., Kably-Ambe, A., Diaz-Perez, M.A. and Krivitzky, S.K. (1990) Evidence that human follicular fluid contains a chemoattractant for spermatozoa. Fertil. Steril. 54, 1180–1182.

Male and female infertility has been observed in mice mutant for GEMC1, MCIDAS, or CCNO due to defective MCC differentiation. In females, MCC loss in the oviducts is the probable cause of infertility. The efferent duct epithelia of males contains MCCs that mobilize luminal fluids to prevent the agglutination of spermatozoa and promote fluid reabsorption. In mice mutant for these genes, degeneration of Sertoli cells, thinning of the seminiferous tubule epithelia, dilation of the rete testes and seminiferous tubules, sperm agglutinations in the efferent ducts, and lack of spermatozoa in the epididymis has been observed in conjunction with defects in MCC development.

Acrosin is a digestive enzyme that acts as a protease. In humans, acrosin is encoded by the ACR gene. Acrosin is released from the acrosome of spermatozoa as a consequence of the acrosome reaction. It aids in the penetration of the Zona Pellucida.

J. Cell. Physiol. 229, 68–78. atrial natriuretic peptide (ANP),Zamir, N., Riven-Kreitman, R., Manor, M., Makler, A., Blumberg, S., Ralt, D. and Eisenbach, M. (1993) Atrial natriuretic peptide attracts human spermatozoa in vitro. Biochem. Biophys. Res. Commun. 197, 116–122.

Nearly all vertebrates undergo sexual reproduction. They produce haploid gametes by meiosis. The smaller, motile gametes are spermatozoa and the larger, non-motile gametes are ova. These fuse by the process of fertilisation to form diploid zygotes, which develop into new individuals.

Sperm Spermiogenesis is the final stage of spermatogenesis, which sees the maturation of spermatids into mature spermatozoa. The spermatid is a more or less circular cell containing a nucleus, Golgi apparatus, centriole and mitochondria. All these components take part in forming the spermatozoon.

The resultant 'sex-sorted' spermatozoa are then able to be used in conjunction with other assisted reproductive technologies such as artificial insemination or in-vitro fertilization (IVF) to produce offspring of the desired sex - in farming animals but also in human medical practice.

Abhydrolase domain-containing protein 2 is a serine hydrolase enzyme that is strongly expressed in human spermatozoa. It is a key controller of sperm hyperactivation, which is a necessary step in allowing sperm to fertilize an egg. It is encoded by the ABHD2 gene.

Affected males therefore suffer from either reduced fertility or infertility. Studies suggest that globozoospermia can be either total (100% round-headed spermatozoa without acrosomes) or partial (20-60% round acrosomeless spermatozoa with normal sperm also identified in the sperm count,) however it is unclear whether these two forms are variations on the same syndrome, or actually different syndromes. Studies have suggested mutations or deletions in three genes are responsible for this condition: SPATA16, PICK1 and DPY19L2. ICSI (intracytoplasmic sperm injection) has previously been used to assist reproduction in globozoospermic patients, however it has not been particularly effective in all patients, due to low fertilisation rates.

Male Luzon fruit bats are no exception, as they display a form of migratory testes, in which their testes are located in the abdomen. Additionally, these male bats have few spermatozoa in both their testes and epididymis, indicating that much of the sperm in not fully mature.

This protein is localized in germ cells of the testis at all stages of spermatogenesis and is localized to the acrosomal region of mature spermatozoa. Alternatively spliced variants that encode different protein isoforms have been described but the full-length sequences of only two have been determined.

Three different guidance mechanisms have been proposed to occur in the mammalian oviduct: thermotaxis, rheotaxis, and chemotaxis.Oliveira, R.G., Tomasi, L., Rovasio, R.A. and Giojalas, L.C. (1999) Increased velocity and induction of chemotactic response in mouse spermatozoa by follicular and oviductal fluids. J. Reprod. Fertil. 115, 23–27.

Additional compounds have been shown to act as chemoattractants for mammalian spermatozoa. They include the chemokine CCL20,Caballero-Campo, P., Buffone, M.G., Benencia, F., Conejo-García, J.R., Rinaudo, P.F and Gerton, G.L. (2014) A role for the chemokine receptor CCR6 in mammalian sperm motility and chemotaxis.

Notably, post-translational modifications of cytoplasmic GAPDH contribute to its functions outside of glycolysis. GAPDH is encoded by a single gene that produces a single mRNA transcript with 8 splice variants, though an isoform does exist as a separate gene that is expressed only in spermatozoa.

Reproduction of two rare Pipistrellus species, with special attention to the fate of spermatozoa in their female genital tracts. Journal of the Mammalogical Society of Japan, 13(2), 77-91. Females give birth in the summer. The average litter size is unknown, but twins have been observed.

The vas deferentia then unite posteriorally to form a central ejaculatory duct, this opens to the outside on an aedeagus or a penis. Accessory glands secrete fluids that comprise the spermatophore. This becomes a package that surrounds and carries the spermatozoa, forming a sperm-containing capsule.

Sperm guidance is the process by which sperm cells (spermatozoa) are directed to the oocyte (egg) for the aim of fertilization. In the case of marine invertebrates the guidance is done by chemotaxis. In the case of mammals, it appears to be done by chemotaxis, thermotaxis and rheotaxis.

Gonadal and epididymal sperm reserves in the rabbit; Estimation of the daily sperm production. Journal of Reproduction and Fertility 15: 15-25.Amann R.P., Johnson L., Thompson D.L. & Pickett B.W. (1976). Daily spermatozoal production, epididymal spermatozoal reserves and transit time of spermatozoa through the epididymis of the rhesus monkey.

Some teleost species are hermaphroditic, which can come in two forms: simultaneous and sequential. In the former, both spermatozoa and eggs are present in the gonads. Simultaneous hermaphroditism typically occurs in species that live in the ocean depths, where potential mates are sparsely dispersed.Wootton and Smith p. 54.

FPP is produced in the prostate gland as a component of the seminal fluid. FPP comes into contact with the spermatozoa during ejaculation, as the sperm and seminal fluid mix. High levels of active FPP prevent capacitation. After ejaculation, the concentration of FPP drops in the female reproductive tract.

Ejaculation is the ejecting of semen from the penis, and is usually accompanied by orgasm. A series of muscular contractions delivers semen, containing male gametes known as sperm cells or spermatozoa, from the penis. It is usually the result of sexual stimulation. Rarely, it is due to prostatic disease.

One of the centrioles of the cell elongates to become the tail of the sperm. A temporary structure called the "manchette" assists in this elongation. During this phase, the developing spermatozoa orient themselves so that their tails point towards the center of the lumen, away from the epithelium.

After the discovery of spermatozoa in 1677 by Dutch microscopist Antonie van Leeuwenhoek, the epigenist theory proved more difficult to defend: How could complex organisms such as human beings develop from such simple organisms? Thereafter, Joseph de Aromatari and then Marcello Malpighi and Jan Swammerdam made observations using microscopes in the late 17th century, and interpreted their findings to develop the preformationist theory. For two centuries, until the development of cell theory, preformationists would oppose epigenicists, and, inside the preformationist camp, spermists (who claimed the homunculus must come from the man) to ovists, who located the homunculus in the ova. Dutch microscopist Antonie van Leeuwenhoek was one of the first to observe spermatozoa.

Sperm guidance by either chemotaxis or thermotaxis can potentially be used to obtain sperm populations that are enriched with capacitated spermatozoa for in vitro fertilization procedures. Indeed, sperm populations selected by thermotaxis were recently shown to have much higher DNA integrity and lower chromatin compaction than unselected spermatozoa and, in mice, to give rise to more and better embryos through intracytoplasmic sperm injection (ICSI), doubling the number of successful pregnancies.Pérez-Cerezales, S., Laguna-Barraza, R., Chacón de Castro, A., Jesús Sánchez-Calabuig, M., Cano-Oliva, E., Javier de Castro-Pita, F., Montoro-Buils, L., Pericuesta, E., Fernández-González, R. and Gutiérrez-Adán, A. (2018) Sperm selection by thermotaxis improves ICSI outcome in mice Sci. Rep. 8, 2902.

When spermatozoa reach the isthmic oviduct, their motility has been reported to be reduced as they attach to epithelium. Near the time of ovulation, hyperactivation occurs. During this process, the flagella move with high curvature and long wavelength.Mortimer, D., Aitken, R. J., Mortimer, S. T., and Pacey, A. A.(1995).

Some of the research includes a paper named Fertilizability of ovine, bovine, and minke whales spermatozoa intracytoplasmically injected into bovine oocytes. Reporter/Producer: Dr Jonica Newby. (Transcript and full program available online) Joji Morishita of JARPA has said the number of samples was required in order to obtain statistically significant data.

The spermatozoa of animals are produced through spermatogenesis inside the male gonads (testicles) via meiotic division. The initial spermatozoon process takes around 70 days to complete. The process starts with the production of spermatogonia from germ cell precursors. These divide and differentiate into spermatocytes, which undergo meiosis to form spermatids.

Where the spermatozoan is about to pierce, the yolk (ooplasm) is drawn out into a conical elevation, termed the cone of attraction or reception cone. Once the spermatozoon has entered, the peripheral portion of the yolk changes into a membrane, the perivitelline membrane, which prevents the passage of additional spermatozoa.

Spermatozoa has been observed in preovulatory females. Juvenile males have soft, small claspers and undeveloped testes with straight, thread-like ampullae ductus deferens. Adolescents' testes have increased weight and claspers are extended and calcified, but are still flexible. Adults have fully formed and calcified claspers and large and developed testes.

Neil Genzlinger of the New York Times said of the original production, that it's "almost certainly unchallenged in the creative use of spermatozoa as a scenic motif." Marilyn Stasio of Variety, in a less glowing review, wrote that it's " a comedy that can’t decide how funny it wants to be".

Calcium ions play a primary role in the regulation of sperm motility. This gene belongs to a family of putative cation channels that are specific to spermatozoa and localize to the flagellum. The protein family features a single repeat with six membrane-spanning segments and a predicted calcium- selective pore region.

Like vertebrates, most invertebrates reproduce at least partly through sexual reproduction. They produce specialized reproductive cells that undergo meiosis to produce smaller, motile spermatozoa or larger, non-motile ova. These fuse to form zygotes, which develop into new individuals. Others are capable of asexual reproduction, or sometimes, both methods of reproduction.

SPATA16 knockout mice are completely infertile, and it is characterized by spermatogenesis arrest and azoospermia. This is where the differentiation process is obstructed during spermatogenesis and creates immotile sperm. In contrast, infertility caused by SPATA16 mutations in male humans develop spermatozoa that are motile, but their sperm exhibit head and acrosome abnormalities.

Acrosin is the major proteinase present in the acrosome of mature spermatozoa. It is stored in the acrosome in its precursor form, proacrosin. Upon stimulus, the acrosome releases its contents onto the zona pellucida. After this reaction occurs, the zymogen form of the protease is then processed into its active form, β-acrosin.

The energy for this process is supplied by ATP produced by mitochondria. The velocity of a sperm in fluid medium is usually 1–4 mm/min. This allows the sperm to move towards an ovum in order to fertilize it. In mammals, spermatozoa mature functionally through a process which is known as capacitation.

Normal spermatogenesis, testis biopsy. High-power view of a seminiferous tubule with normal spermatogenesis. Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules.

Additional compounds have been shown to act as chemoattractants for mammalian spermatozoa. They include the chemokine CCL20,Caballero-Campo, P., Buffone, M.G., Benencia, F., Conejo-García, J.R., Rinaudo, P.F and Gerton, G.L. (2014) A role for the chemokine receptor CCR6 in mammalian sperm motility and chemotaxis. J. Cell. Physiol. 229, 68–78.

The protein encoded by this gene is coordinately expressed with activator of cAMP-responsive element modulator (CREM). It is associated with CREM and confers a powerful transcriptional activation function. CREM acts as a transcription factor essential for the differentiation of spermatids into mature spermatozoa. There are multiple polyadenylation sites found in this gene.

He described the spermatozoa of about 30 species, and thought he saw in semen "all manner of great and small vessels, so various and so numerous that I do not doubt that they be nerves, arteries and veins...And when I saw them, I felt convinced that, in no full grown body, are there any vessels which may not be found likewise in semen." (Friedman 76-7)Friedman, David M. A Mind of Its Own: A Cultural History of the Penis. New York: The Free Press, 2001 Leeuwenhoek discovered that the origin of semen was the testicles and was a committed preformationist and spermist. He reasoned that the movement of spermatozoa was evidence of animal life, which presumed a complex structure and, for human sperm, a soul.

This raised the possibility that, in mammals, chemotaxis is not solely a guidance mechanism but it is also a mechanism of sperm selection. Importantly, the fraction of capacitated (and, hence, chemotactically responsive) spermatozoa is low (~10% in humans), the life span of the capacitated/chemotactic state is short (1–4 hours in humans), a spermatozoon can be at this state only once in its lifetime, and sperm individuals become capacitated/chemotactic at different time points, resulting in continuous replacement of capacitated/chemotactic cells within the sperm population, i.e., prolonged availability of capacitated cells.Cohen-Dayag, A., Ralt, D., Tur-Kaspa, I., Manor, M., Makler, A., Dor, J., Mashiach, S. and Eisenbach, M. (1994) Sequential acquisition of chemotactic responsiveness by human spermatozoa. Biol. Reprod.

The secretory endpieces of these glands are lined with simple columnar epithelium; the main ducts are lined with stratified columnar epithelium. These glands do not occur in carnivores, but are present in some form in horses, ruminants and swine. Seminal fluid, the product of this gland, serves as a vehicle for the transport of spermatozoa.

Don Wayne Fawcett (March 14, 1917 - May 7, 2009) Don Wayne Fawcett (March 14, 1917 - May 7, 2009) was a pioneer of electron microscopy and one of its greatest practitioners for studying the organization of cells and tissues. His greatest achievement was his description of the structure of spermatozoa and the male reproductive system.

This protein localizes to the plasma membrane of germ cells in the testis and to the post-acrosomal plasma membrane of mature spermatozoa. Recombinant polypeptide binds GTP and exhibits GTPase activity. Thus, this protein may regulate GTP signal transduction pathways involved in spermatogenesis and fertilization. Two transcript variants of this gene encode the same protein.

Hamster egg-penetration test (HEPT) (or simply Sperm penetration test) is an in-vitro test used to study physiological profile of spermatozoa. It makes use of zona-free hamster egg, which resembles human ovum. A normal sperm is capable of penetrating the egg, showing its fertilizing capacity. The test is expensive and not reliable.

However, this problem only occurs in about 5% of men that have the test done. This test is rather expensive and provides limited information on a man's fertility. In other cases, such as in the wood mouse Apodemus sylvaticus, premature acrosome reactions have been found to cause increased motility in aggregates of spermatozoa promoting fertilization.

H1 histone family, member N, testis-specific is a member of the histone family of nuclear proteins which are a component of chromatin. In humans, this protein is encoded by the H1FNT gene. The H1FNT protein is essential for nuclear formation in spermatozoa, and is involved in the replacement of histones with protamines during spermiogenesis.

Male with young bird in thumb Eggs of P. pyrrhula europoea MHNT It builds its nest in a bush, (preferably more than four metres tall and wide), mature stands of scrub, or tree, laying four to seven eggs. It is peculiar among the Passeriformes for having spermatozoa with a rounded head and a blunt acrosome.

The spermatozoa are filiform and pointed at one end, and the anterior end is a rounded head. The larvae are lecithotrophic. The adults are herbivorous and feed with their rhipidoglossan radula on macroalgae, preferring red or brown algae. Sizes vary from (Haliotis pulcherrima) to , while Haliotis rufescens is the largest of the genus at .

The discovery of mammalian sperm chemotaxis and the realization that it can guide spermatozoa for short distances only, estimated at the order of millimeters,Pérez-Cerezales, S., Boryshpolets, S. and Eisenbach, M. (2015) Behavioral mechanisms of mammalian sperm guidance. Asian J. Androl. 17, 628-632. triggered a search for potential long-range guidance mechanisms.

Temperature regulation ensures maximum sperm output. One interesting observation about the species, in particular the males, is the morphology of the spermatozoa. They develop falciform (sickle-shaped) heads after meiosis and before spermiation (release during ejaculation). The hook located at the tip of the head adheres to the surface of the head prior to deployment.

In that year, genetic analysis revealed that the two species were distinct, making the Tete veld rat an example of a cryptic species. Other than analysis of chromosomes or mitochondrial DNA, the two species can only be reliably distinguished by the shape of their spermatozoa, which have an unusual spatulated shape in Tete veld rats.

W is involved in spermatogenesis, telomere associated functions in sperm and is found in spermatogenic cells. It is characterized by the extension of the N-terminal tail. subH2B participates in regulation of spermiogenesis and is found in non-nucleosomal particle in the subacrosome of spermatozoa. This variant has a bipartite nuclear localization signal. H2B.

Australian emperor laying egg, guarded by the male Insect species make up more than two- thirds of all extant animal species. Most insect species reproduce sexually, though some species are facultatively parthenogenetic. Many insects species have sexual dimorphism, while in others the sexes look nearly identical. Typically they have two sexes with males producing spermatozoa and females ova.

Cohen was born in The Hague in The Netherlands. He received his B.Sc. in Biochemistry, Faculty of Biology, from the State University of Leiden. He went on to receive an M.Sc. in Reproductive Physiology from Leiden University. In 1981, he was awarded his PhD in Medicine from Erasmus University for his thesis, Interaction between human spermatozoa and hamster oocytes.

The autopsy revealed that she had been intoxicated before being assaulted. Isolated traces of sperm were found on her body. The sperm however contained no spermatozoa, meaning her attacker was infertile. The DNA was neither a match to serial killer Francis Heaulme nor to two other suspects who were known to be in the area at the time.

For humans, the entire process of spermatogenesis is variously estimated as taking 74 days (according to tritium-labelled biopsies) and approximately 120 days (according to DNA clock measurements). Including the transport on ductal system, it takes 3 months. Testes produce 200 to 300 million spermatozoa daily. However, only about half or 100 million of these become viable sperm.

Bactrian camels ovulate after insemination into the vagina; it is the seminal plasma, but not the spermatozoa, which induces ovulation. Ovulation occurs in 87% of females after insemination: 66% ovulate within 36 hours and the rest by 48 hours (the same as natural mating). The least amount of semen required to elicit ovulation is about 1.0 ml.

In 1827, von Baer observed a therian mammalian egg for the first time. Oscar Hertwig (1876), in Germany, described the fusion of nuclei of spermatozoa and of ova from sea urchin.Birkhead, T.R. & Montgomerie, R. (2009). Three centuries of sperm research, pp 1-42 in: Birkhead, T. R., Hosken, D. J. & Pitnick, S. Sperm Biology: An Evolutionary Perspective.

Total motile spermatozoa (TMS) or total motile sperm count (TMSC) is a combination of sperm count, motility and volume, measuring how many million sperm cells in an entire ejaculate are motile. Use of approximately 20 million sperm of motility grade c or d in ICI, and 5 million ones in IUI may be an approximate recommendation.

Chemotaxis and thermotaxis can also be exploited possibly as a diagnostic tool to assess sperm quality. In addition, these processes can potentially be used, in the long run, as a means of contraception by interfering with the normal process of fertilization.Eisenbach, M. and Tur- Kaspa, I. (1999) Do human eggs attract spermatozoa? BioEssays 21, 203–210.

In Drosophila, geranylgeranyl pyrophosphate is synthesised by HMG-CoA encoded by the Columbus gene. Geranylgeranyl pyrophosphate is utilised as a chemoattractant for migrating germ cells that have traversed the midgut epithelia. The attractant signal is produced at the gonadal precursors, directing the germ cells to these sites, where they will differentiate into ova (eggs) and spermatozoa (sperm).

During the maturity, the follicles of the gonads are filled with multiple layers of mature sperm.The mature spermatozoa exhibit a rounded shape are slightly dorso-ventrally flattened. A thin layer of spermatocytes is present at the periphery. Spawning is when the individuals have mated, and therefore the follicles in the gonads are empty due to the sperm being released.

An aneugen is a substance that causes a daughter cell to have an abnormal number of chromosomes or aneuploidy. A substance's aneugenicity reflects its ability to induce aneuploidy. Exposure of males to lifestyle, environmental and/or occupational hazards may increase the risk of spermatozoa aneuploidy. Tobacco smoke contains chemicals that cause DNA damage (see Tobacco smoking#Health).

Spermatogenesis, the process for producing spermatozoa, takes place in the seminiferous tubules. During spermatogenesis, the DNA of spermatogenic cells in the seminiferous tubules is subject to damage from such sources as reactive oxygen species. The genomic integrity of spermatogenic cells is protected by DNA repair processes. Deficiencies in the enzymes employed in these repair processes may lead to infertility.

Peritubular myoid cells are responsible for the contractile nature of the seminiferous tubule. This contraction helps move the spermatozoa and fluid to the rete testes. There are a number of mediators involved in the regulation of contraction. Oxytocin produced by leydig cells has been shown to be a driving factor in the contractions by acting on peritubular myoid cells.

Decapacitation factor (DF) is composed of factors in seminal plasma which modulates the fertilizing ability of spermatozoa. The activity is achieved by interaction between cholesterol, phospholipids and fibronectin-like substances and delivered via small vesicles in seminal plasma. DF prevents onset of capacitation. Physiologically it is achieved through spermatozoal membrane stabilization by maintaining physiological cholesterol/phospholipid ratio.

Allogamy or cross-fertilization is the fertilization of an ovum from one individual with the spermatozoa of another. By contrast, autogamy is the term used for self-fertilization. In humans, the fertilization event is an instance of allogamy. Self-fertilization occurs in hermaphroditic organisms where the two gametes fused in fertilization come from the same individual.

These serve as storage for sperm deposited by males. It contains glands which can nourish the spermatozoa until they can be released to fertilize eggs. Male jewel bugs of the genus Hotea possess an unusually large, spiky, and heavily sclerotized genitalia. They are used in a mating practice known as traumatic insemination, a result of evolutionary sexual conflict.

Their ultrastructure plays an important role in classifying eukaryotes. Among protoctists and microscopic animals, a flagellate is an organism with one or more flagella. Some cells in other animals may be flagellate, for instance the spermatozoa of most animal phyla. Flowering plants do not produce flagellate cells, but ferns, mosses, green algae, and some gymnosperms and closely related plants do so.

Molecular reproduction and development. 2009;76(12):1188-1199. Izumo-1 located on mature spermatozoa that have undergone capacitation binds to its receptor Juno, which is located on the oolemma of eggs. Bianchi E, Doe B, Goulding D, Sanger Mouse Genetics Project, Wright GJ. Juno is the egg Izumo receptor and is essential for mammalian fertilisation. Nature. 2014;508(7497):483-487.

Liverpool studies the role of hydrodynamic interactions in the collective behaviour of particles in a fluid. He observed that swimming bacteria, algae and spermatozoa could be described as "living liquid crystals". By understanding the movement of artificial 'swimmers' in soft matter, he hopes to design new cancer treatments. After his PhD, Liverpool joined University of Cologne as a postdoctoral researcher.

Like other annelids, these worms possess well-developed nervous systems with a central brain and many supporting ganglia, including pedal ganglia, unique to the Polychaeta. Like other polychaetes, S. giganteus excretes with fully developed nephridia. When they reproduce, they simply shed their gametes straight into the water where the eggs and spermatozoa become part of the zooplankton to be carried by the currents.

Randall himself specialised in using the electron microscope, first studying the fine structure of spermatozoa and then concentrating on collagen. In 1958 he published a study of the structure of protozoa. He set up a new group to use the cilia of protozoa as a model system for the analysis of morphogenesis by correlating the structural and biochemical differences in mutants.

The semen exuded by the male congeals into a large, spongy mass inside the female's uterus, in which the individual spermatozoa are embedded. Called a "spermatozeugma", the function of this short-lived structure is unknown. Newborn finetooth sharks measure long. Shallow bays and estuaries, such as Bull's Bay in South Carolina, serve as critical nursery areas for newborns and juveniles.

The cumulus oophorus, (discus proligerus), is a cluster of cells that surround the oocyte both in the ovarian follicle and after ovulation. In the antral follicle, it may be regarded as an extension of the membrana granulosa. The innermost layer of these cells is the corona radiata. This layer of cells must be penetrated by spermatozoa for fertilization to occur.

The theory that located the homonculus in the egg was called ovism. But, when spermatozoa were discovered, a rival camp of spermists sprang up, claiming that the homunculus must come from the male. In fact, the term "spermatozoon," coined by Karl Ernst von Baer, means "seed animals." With the discovery of sperm and the concept of spermism came a religious quandary.

The tips of these tufts enclose a flame-cell like those found in flatworms and other animals, and these probably function as excretory organs. As the animals mature, diverticula arise on the tubes of these organs, which develop either spermatozoa or ova. These sex cells pass out through the ducts. The perigenital area of the genus Tubiluchus exhibit sexual dimorphism.

Between the ciliated cells are peg cells, which contain apical granules and produce tubular fluid. This fluid contains nutrients for spermatozoa, oocytes, and zygotes. The secretions also promote capacitation of the sperm by removing glycoproteins and other molecules from the plasma membrane of the sperm. Progesterone increases the number of peg cells, while estrogen increases their height and secretory activity.

Exposure of spermatozoa to lifestyle, environmental and/or occupational hazards may increase the risk of aneuploidy. Cigarette smoke is a known aneugen (aneuploidy inducing agent). It is associated with increases in aneuploidy ranging from 1.5 to 3.0-fold. Other studies indicate factors such as alcohol consumption, occupational exposure to benzene, and exposure to the insecticides fenvalerate and carbaryl also increase aneuploidy.

They are able to aestivate for multiple years if necessary, burrowing into mud and exuding a cocoon of dead skin cells. Known predators include the American alligator and the mud snake. Their spermatozoa possess a pair of flagella, and their courtship behavior is unknown. Mating occurs in February and March, with mothers guarding clutches of eggs that hatch about two months later.

Despite his contributions, De Graaf made a number of errors in addition to believing that the ovum was the follicle. He never actually consulted the ancient texts but merely repeated the accounts of others compounding their inaccuracies. Because he observed rabbits rather than humans, he assumed fertilisation took place in the ovary. He believed that the seminal vesicles stored spermatozoa.

The male European corn borer produces a spermatophore ejaculate that contains spermatozoa to fertilize the female and protein to nourish the female, a nuptial gift. The cost of producing a spermatophore is relatively low compared to the female investment in oviposition. Males mate an average of 3.8 times during their life. The average refractory period between matings for the male is 1.6 days.

Luminal composition and maturation of spermatozoa in the male genital ducts of the Port Jackson shark, Heterodontus portusjacksoni. The Journal of Experimental Zoology 230: 417-426. In the monotreme echidna, the initial segment, where sperm undergo maturation, is much larger than the terminal segment (Figure 1B), the later segment being the sperm storage region of the epididymis.Djakiew, D. & Jones, J.C. (1983).

Studies in mice have shown that DHA is essential for acrosome reaction and a DHA deficiency results in abnormal sperm morphology, loss of motility and infertility; which can be restored by dietary DHA supplementation. Furthermore, the supplementation with DHA in human has been reported to increase sperm motility. But also, DHA supplement can protect spermatozoa against the damage caused by the cryopresevation process.

Each pair lays only one egg per year. Pairs in the same colony usually lay around the same time, but very rarely this occurs over more than one week. The female's sperm storage glands in the oviduct help select spermatozoa during the race to the egg cell. The egg is oval, off-white in color with lavender, gray and brown highlights.

After a 1993 PhD titled 'The effect of cryopreservation on human spermatozoa' at the University of Bristol, McLaughlin moved to the University of Newcastle, and then to the University of Auckland rising to full professor. She is shortly to take up a position at the University of Canberra. Much of McLaughlin's research involves in vitro understanding of the principals of assisted reproduction.

Human male XY chromosomes after G-banding In humans, half of spermatozoa carry X chromosome and the other half Y chromosome. A single gene (SRY) present on the Y chromosome acts as a signal to set the developmental pathway towards maleness. Presence of this gene starts off the process of virilization. This and other factors result in the sex differences in humans.

Semen parameters can be altered in patients for several weeks post-symptoms onset, and spermatozoa can be infectious. Since October 2016, the CDC has advised men who have traveled to an area with Zika should use condoms or not have sex for at least six months after their return as the virus is still transmissible even if symptoms never develop.

The blood-testis barrier separates the immune system and the developing spermatozoa. The tight junction between the Sertoli cells form the blood- testis barrier but it is usually breached by physiological leakage. Not all sperms are protected by the barrier because spermatogonia and early spermatocytes are located below the junction. They are protected by other means like immunologic tolerance and immunomodulation.

There are two sexes that look alike. A pair of gonads are located in the mid-region of the trunk, and open to pores in the final segment. In most species, the sperm duct includes two or three spiny structures that presumably aid in copulation, although the details are unknown. Individual spermatozoa can reach a quarter of the total body length.

Anisogamy is the phenomenon of fertilization of large gametes (egg cells, ova) by (or with) small gametes (sperm cells: spermatozoa or spermatia). Gamete size difference is the fundamental difference between females and males. Anisogamy first evolved in multicellular haploid species after the differentiation of different mating types had already been established. However, in Ascomycetes, anisogamy evolved from isogamy before mating types.

In spite of his scientific background, Spallanzani endorsed preformationism, an idea that organisms develop from their own miniature selves; e.g. animals from minute animals, animalcules. In 1784, he performed filtration experiment in which he successfully separated seminal fluid of frogs – a liquid portion and a gelatinous animalcule (spermatozoa) portion. But then he assumed that it was the liquid part which could induce fertilisation.

Semenogelin-1 is a protein that in humans is encoded by the SEMG1 gene. The protein encoded by this gene is the predominant protein in semen. The encoded secreted protein is involved in the formation of a gel matrix that encases ejaculated spermatozoa. The prostate-specific antigen (PSA) protease processes this protein into smaller peptides, with each possibly having a separate function.

A saccular dilation in the spermatheca stores spermatozoa received from males during copulation. It can maximize efficiency and use of sperm. Derived from the ectoderm, the spermatheca is covered in fat and tissue and has three main regions: the distal region, the medial region and the proximal region. The coiled distal region is responsible for the control of sperm flow.

Telegony, once a popular theory among nineteenth century biologists, was largely dismissed with the arrival of Mendelian genetics. However, in 2014 the evolutionary ecologists A. J. Crean and colleagues reported a seemingly telegonic phenomenon in a fly, Telostylinus angusticollis. Y. S. Liu has proposed possible molecular mechanisms that may account for telegony; however, his work is predicated on the beliefs of pre- Mendelian breeders to reinforce the idea that traits are passed from earlier matings. The proposed mechanisms include the penetration of spermatozoa into the somatic tissues of the female genital tract, the incorporation of the DNA released by spermatozoa into maternal somatic cells, the presence of fetal DNA in maternal blood, incorporation of exogenous DNA into somatic cells, presence of fetal cells and fetal DNA in maternal blood and sperm RNA-mediated non- Mendelian inheritance of epigenetic changes.

There is suspicion that many toxic substances, including several types of medication and hormones, and also constituents of the diet, influence sperm quality. While a few chemicals with known effects on fertility have been excluded from human consumption, we cannot know if others remain undiscovered. Many products that come into direct contact with spermatozoa lack adequate testing for any adverse effect on semen quality.

Spermatogenesis arrest is known as the interruption of germinal cells of specific cellular type, which elicits an altered spermatozoa formation. Spermatogenic arrest is usually due to genetic factors resulting in irreversible azoospermia. However some cases may be consecutive to hormonal, thermic, or toxic factors and may be reversible either spontaneously or after a specific treatment. Spermatogenic arrest results in either oligospermia or azoospermia in men.

In males, meiosis occurs during spermatogenesis in the seminiferous tubules of the testicles. Meiosis during spermatogenesis is specific to a type of cell called spermatocytes, which will later mature to become spermatozoa. Meiosis of primordial germ cells happens at the time of puberty, much later than in females. Tissues of the male testis suppress meiosis by degrading retinoic acid, proposed to be a stimulator of meiosis.

Researchers at Münster University developed in vitro culture conditions using a three-dimensional agar culture system which induces mouse testicular germ cells to reach the final stages of spermatogenesis, including spermatozoa generation. If reproduced in humans, this could potentially enable infertile men to father children with their own sperm. Researchers from Montana State University developed precursors of sperm from skin cells of infertile men. Sharpe et al.

Spermatogenesis is the process in which spermatozoa are produced from spermatogonial stem cells by way of mitosis and meiosis. A major function of meiosis is homologous recombinational repair of this germline DNA. RNF8 plays an essential role in signaling the presence of DNA double-strand breaks. Male mice with a gene knockout for RNF8 have impaired spermatogenesis, apparently due to a defect in homologous recombinational repair.

Grossly the prostate gland can be divided into two parts: the body and the disseminate part. Low cuboidal to low columnar epithelium provides the lining for this compound, tubuloalveolar gland which consists primarily of serous secretory end pieces. The secretion of this gland is more serous in dogs and more mucous in bulls. It serves to promote the movement of spermatozoa and to form a vaginal plug.

Development of oogonial stem cells in C. elegans adult hermaphrodites The nematode Caenorhabditis elegans (C. elegans) are nematodes can have hermaphroditic or male reproductive capabilities. In males, only spermatogenesis occurs; hermaphrodites can produce spermatozoa until adulthood, when oogenesis takes over. All oogonial stem cells in C. elegans are derived from one distal-tip cell (DTC), which acts as a niche to ensure that germline proliferation continues.

Spermatogonial stem cells are the precursors to spermatozoa, which are produced through a series of differentiation steps. This is the alternative SSC outcome to self-renewal. SSCs survive within microenvironments, termed niches, which provide extrinsic stimuli that drive stem cell differentiation or self-renewal. The SSC niche is found in the seminiferous epithelium of mammalian testis, and is primarily constituted of Sertoli and peritubular myoid cells.

A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes (sex cells) and sex hormones of an organism. In the female of the species the reproductive cells are the egg cells, and in the male the reproductive cells are the sperm. The male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells.

Levonorgestrel is a progestogen, i.e. progesterone-receptor agonist. The hormonal IUD's primary mechanism of action is to prevent fertilization. p. S28: > Conclusions > Active substances released from the IUD or IUS, together with products > derived from the inflammatory reaction present in the luminal fluids of the > genital tract, are toxic for spermatozoa and oocytes, preventing the > encounter of healthy gametes and the formation of viable embryos.

Some animals' regenerative capabilities challenged preformationism, and Abraham Trembley's studies of the hydra convinced various authorities to reject their former views. Lazaro Spallanzani, Trembley's nephew, experimented with regeneration and semen, but failed to discern the importance of spermatozoa, dismissing them as parasitic worms and concluding instead that it was the liquid portion of semen that caused the preformed organism in the ovum to develop.

Most aquatic animals, except for aquatic mammals and reptiles, reproduce through the process of spawning. Spawn consists of the reproductive cells (gametes) of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa (milt) to fertilize the eggs.Spawn Fishbase Glossary.

In all bed bug species except Primicimex cavernis, sperm are injected into the mesospermalege.Reinhardt, K. & Siva- Jothy, M. T. (2007) "Biology of the bed bugs (Cimicidae)," Annual Review of Entomology, 52, 351–374. The structure contains two main types of hemocyte, though their function is not yet fully understood. The first of these is phagocytic and may absorb seminal fluid, whereas the other may digest spermatozoa.

The first recorded observations of the relationship between cervical mucus and survival of spermatozoa come from the mid-19th century. The topic was not systematically studied, however, for almost another century. In 1948, Erik Odeblad was studying mycoplasms in the female genital tract. During the course of his studies, he noticed that cervical mucus changed in a predictable pattern through the course of a woman's cycle.

These cells are called spermatogonial stem cells. The mitotic division of these produces two types of cells. Type A cells replenish the stem cells, and type B cells differentiate into primary spermatocytes. The primary spermatocyte divides meiotically (Meiosis I) into two secondary spermatocytes; each secondary spermatocyte divides into two equal haploid spermatids by Meiosis II. The spermatids are transformed into spermatozoa (sperm) by the process of spermiogenesis.

Hermann Fol continued Hertwig's research by testing the effects of injecting several spermatozoa into an egg, and found that the process did not work with more than one spermatozoon. Flemming began his research of cell division starting in 1868. The study of cells was an increasingly popular topic in this time period. By 1873, Schneider had already begun to describe the steps of cell division.

Tyrosine phosphorylation mediates in signal transduction pathways during germ cell development and determines their association with the differentiation of a functional gamete. Until testicular germ cells differentiate into spermatozoa, cAMP-induced tyrosine phosphorylation is not detectable. Entry of these cells into the epididymis is accompanied by sudden activation of the tyrosine phosphorylation pathway, initially in the principal piece of the cell and subsequently in the midpiece.

The first-line method for sperm retrieval in men with spinal cord injury is penile vibratory stimulation (PVS). The penile vibratory stimulator is a plier-like device that is placed around the glans penis to stimulate it by vibration. In case of failure with PVS, spermatozoa are sometimes collected by electroejaculation, or surgically by per cutaneous epididymal sperm aspiration (PESA) or testicular sperm extraction (TESE).

The spermatozoon of Chimaericola leptogaster (drawing) The first molecular sequences obtained from Chimaericola leptogaster suggested that the Chimaericolidae were a basal group within the Polyopisthocotylea. Chimaericola leptogaster was studied with transmission electron microscopy. Several organs have been investigated in details: vaginae, clamps, digestive system, and spermiogenesis and spermatozoa. These ultrastructural results have confirmed the basal position of the species in comparison to marine Polyopisthocotylea.

Mitotic germ stem cells, spermatogonia, divide by mitosis to produce spermatocytes committed to meiosis. The spermatocytes divide by meiosis to form spermatids. The post- meiotic spermatids differentiate through spermiogenesis to become mature and functional spermatozoa. Spermatogenic cells at different stages of development in the mouse have a frequency of mutation that is 5 to 10-fold lower than the mutation frequency in somatic cells.

Spermatozoa that fail to incorporate themselves into mobile trains are less likely to engage in fertilization. Other evidence suggests no link between sperm competition and sperm hook morphology. Selection to produce more sperm can also select for the evolution of larger testes. Relationships across species between the frequency of multiple mating by females and male testis size are well documented across many groups of animals.

In those species with two sexes, males may differ from females in ways other than the production of spermatozoa. In many insects and fish, the male is smaller than the female. In seed plants, which exhibit alternation of generations, the female and male parts are both included within the sporophyte sex organ of a single organism. In mammals, including humans, males are typically larger than females.

Necrospermia (or necrozoospermia) is a condition in which there is a low percentage of live and a very high percentage of immotile spermatozoa in semen.World Health Organization (WHO) Laboratory Manual for the Examination and Processing of Human Semen, 5th Edition, 2010 It can be diagnosed via a semen analysis with vitality staining performed to determine whether the sperm are dead or alive and immotile.

Males release their sperm into sea water. While the released agglomerations of spermatozoa, referred to as spermatozeugmata, do not remain intact for more than 30 seconds in laboratory conditions, they may maintain integrity for longer periods of time in specific hydrothermal vent conditions. Usually, the spermatozeugmata swim into the female's tube. Movement of the cluster is conferred by the collective action of each spermatozoon moving independently.

The Olympia oyster spawns between the months of May and August, when the water reaches temperatures above 14 degrees Celsius. During the oyster's first spawning cycle they will act as a male and then switch between sexes during their following spawning cycles. The males release their spermatozoa from their mantle cavity in the form of sperm balls. These balls dissolve in the water into free floating sperm.

The zona pellucida is surrounded by the corona radiata. The corona is composed of cells that care for the egg when it is emitted from the ovary. This structure binds spermatozoa, and is required to initiate the acrosome reaction. In the mouse (the best characterised mammalian system), the zona glycoprotein, ZP3, is responsible for sperm binding, adhering to proteins on the sperm plasma membrane.

During fertilization in Hippocampus kuda the brood pouch was found to be open for only six seconds while egg deposition occurred. During this time seawater entered the pouch where the spermatozoa and eggs meet in a seawater milieu. This hyperosmotic environment facilitates sperm activation and motility. The fertilization is therefore regarded as being physiologically ‘external’ within a physically ‘internal’ environment after the closure of the pouch.

Depending on the total amount of spermatozoa in the semen sample, either low or high, it can be just washed or capacitated via swim-up or gradients, respectively. A medical animation still showing the ICSI procedure. The procedure is done under a microscope using multiple micromanipulation devices (micromanipulator, microinjectors and micropipettes). A holding pipette stabilizes the mature oocyte with gentle suction applied by a microinjector.

C. Polge, AU Smith, AS Parkes, Revival of spermatozoa Effective vitrification and dehydration at low temperatures Nature, 164 (1949), p. 666 This led to a much wider use of cryopreservation today, with many organs, tissues and cells routinely stored at low temperatures. Large organs such as hearts are usually stored and transported, for short times only, at cool but not freezing temperatures for transplantation.

This, however, does not exclude the occurrence of spatial temperature sensing in addition to temporal sensing. Human spermatozoa can respond thermotactically within a wide temperature range (at least 29–41 °C). Within this range they preferentially accumulate in warmer temperatures rather than at a single specific, preferred temperature. Amazingly, they can sense and thermotactically respond to temperature gradients as low as <0.014 °C/mm.

The major reproductive organs of the male can be grouped into three categories. The first category produces and stores sperm (spermatozoa). These are produced in the testes, which are housed in the temperature-regulating scrotum; immature sperm then travel to the epididymis for development and storage. The second category are the ejaculatory fluid producing glands which include the Cowper's gland (also called bulbo-urethral gland), seminal vesicles, prostate, and vas deferens.

The active enzyme then functions in the lysis of the zona pellucida, thus facilitating penetration of the sperm through the innermost glycoprotein layers of the ovum. The importance of acrosin in the acrosome reaction has been contested. It has been found through genetic knockout experiments that mouse spermatozoa lacking β-acrosin (the active protease) still have the ability to penetrate the zona pellucida.T. Baba, S. Azuma, S. Kashiwabara, Y. Toyoda.

As a graduate student of Hokkaido University in Japan Yanagimachi studied fish (herring) fertilization and the sexual organization of rhizocephalans (parasitic barnacles). In fish, he discovered calcium-dependent, chemotactic movement of spermatozoa into the micropyle through which the fertilizing spermatozoon enters the egg. This was the first discovery of sperm chemotaxis in vertebrate animals. In rhizocephala, he found that adults are not hermaphroditic as generally thought, but bisexual.

The process of spermatogenesis occurs in male mammals within the testis. This is the process of rounded spermatocytes developing into elongating spermatozoa with a flagellum. Spermatogenesis has two successive phases, one being spermiogenesis within the Sertoli cells of the testis and the other being maturation within the epididymis. The adherens junctions in the Sertoli cells is one of the only epithelial cell-cell junction that lacks the expression of vezatin.

A knockout model for Lfng has been created in mice, and without Lfng, mice have shorter tails, and impaired rib, lung, and somite development. A deficiency of Lfng in male mice has also been associated with lack of spermatozoa in the epididymis of many mice; however, spermatogenesis was not impaired. Rather, the male mice were subfertile. In female mice, Lfng deficiency led to infertility because of abnormal folliculogenesis.

Furthermore, scanning laser polarimetry utilises the birefringence of the optic nerve fibre layer to indirectly quantify its thickness, which is of use in the assessment and monitoring of glaucoma. Birefringence characteristics in sperm heads allow the selection of spermatozoa for intracytoplasmic sperm injection. Likewise, zona imaging uses birefringence on oocytes to select the ones with highest chances of successful pregnancy. Birefringence of particles biopsied from pulmonary nodules indicates silicosis.

The protein encoded by this gene is a type I membrane protein and is a regulatory part of the complement system. The encoded protein has cofactor activity for inactivation (through cleavage) of complement components C3b and C4b by serum factor I, which protects the host cell from damage by complement. The protein encoded by this gene may be involved in the fusion of the spermatozoa with the oocyte during fertilization.

However, increasing the levels of FSH will increase the production of spermatozoa by preventing the apoptosis of type A spermatogonia. The hormone inhibin acts to decrease the levels of FSH. Studies from rodent models suggest that gonadotropins (both LH and FSH) support the process of spermatogenesis by suppressing the proapoptotic signals and therefore promote spermatogenic cell survival. The Sertoli cells themselves mediate parts of spermatogenesis through hormone production.

The terminalia of adult female insects include internal structures for receiving the male copulatory organ and his spermatozoa, and external structures used for oviposition (egg- laying). Most female insects have an egg-laying tube, or ovipositor; it is absent in termites, parasitic lice, many Plecoptera, and most Ephemeroptera. Ovipositors take two forms: # true, or appendicular, formed from appendages of abdominal segments 8 and 9; # substitutional, composed of extensible posterior abdominal segments.

As in non-mammalian species, the end signal in chemotaxis for changing the direction of swimming is Ca2+.Sugiyama, H. and Chandler, D.E. (2014) Sperm guidance to the egg finds calcium at the helm. Protoplasma 251, 461-475. The discovery of progesterone as a chemoattractant led to the identification of its receptor on the sperm surface – CatSper, a Ca2+ channel present exclusively in the tail of mammalian spermatozoa.

They are involved in sperm thermotaxis via at least two signaling pathways: a phospholipase C signaling pathway and a cyclic-nucleotide pathway. The former was shown by pharmacological means in human spermatozoa to involve the enzyme phospholipase C, an inositol trisphosphate receptor located on internal calcium stores, the calcium channel TRPC3, and intracellular calcium. The cyclic-nucleotide pathway was, hitherto, shown to involve phosphodiesterase. Blocking both pathways fully inhibits sperm thermotaxis.

As in non-mammalian species, the end signal in chemotaxis for changing the direction of swimming is Ca2+.Sugiyama, H. and Chandler, D.E. (2014) Sperm guidance to the egg finds calcium at the helm. Protoplasma 251, 461-475. The discovery of progesterone as a chemoattractant led to the identification of its receptor on the sperm surface – CatSper, a Ca2+ channel present exclusively in the tail of mammalian spermatozoa.

The coiled epididymal duct within the cauda epididymis does not appear to be particularly long, and so may be limited in its capacity to store sperm in comparison to scrotal mammals. Limited sperm storage in the reptilian epididymis may be circumvented by the ability of female reptiles to store viable spermatozoa within their reproductive tract for utilization months or years after insemination.Sever, D.M. & Hamlett, W.C. (2002). Female sperm storage in reptiles.

Asthenozoospermia (or asthenospermia) is the medical term for reduced sperm motility. Complete asthenozoospermia, that is, 100% immotile spermatozoa in the ejaculate, is reported at a frequency of 1 of 5000 men. Causes of complete asthenozoospermia include metabolic deficiencies, ultrastructural abnormalities of the sperm flagellum (see Primary ciliary dyskinesia) and necrozoospermia. It decreases the sperm quality and is therefore one of the major causes of infertility or reduced fertility in men.

The spermatid is the haploid male gametid that results from division of secondary spermatocytes. As a result of meiosis, each spermatid contains only half of the genetic material present in the original primary spermatocyte. Spermatids are connected by cytoplasmic material and have superfluous cytoplasmic material around their nuclei. When formed, early round spermatids must undergo further maturational events to develop into spermatozoa, a process termed spermiogenesis (also termed spermeteliosis).

The membranes of the ER are continuous with the outer nuclear membrane. The endoplasmic reticulum is not found in red blood cells, or spermatozoa. The two types of ER share many of the same proteins and engage in certain common activities such as the synthesis of certain lipids and cholesterol. Different types of cells contain different ratios of the two types of ER depending on the activities of the cell.

Females appear soon afterwards, emitting flashes of light, and swimming in small circles on the water surface. Both the body of the female and the secretions it produces are luminous and sometimes a male gyrates on the surface with a female. The display ceases within half an hour of its commencement. Water samples taken in the vicinity of males and females and their luminous secretions contain spermatozoa and eggs respectively.

Near to Shopian a town about 40 km away from Srinagar, Kashmir two women were found dead on the banks of Rambiara Nala, the autopsies were conducted by a team of doctors of Kashmir including one lady doctor. The cause of death was given as head injury. The vaginal swabs were preserved which were positive for spermatozoa at FSL Srinagar. There was agitation led by Majlis Musharraf in Kashmir.

They are involved in sperm thermotaxis via two signaling pathways—a phospholipase C signaling pathway and a cyclic-nucleotide pathway. The former was shown by pharmacological means in human spermatozoa to involve the enzyme phospholipase C, an inositol trisphosphate receptor calcium channel located on internal calcium stores, the calcium channel TRPC3, and intracellular calcium. The latter was hitherto shown to involve phosphodiesterase. Blocking both pathways fully inhibits sperm thermotaxis.

Artificial insemination is a mechanism in which spermatozoa are deposited into the reproductive tract of a female. Artificial insemination provides a number of benefits relating to reproduction in the poultry industry. Broiler breeds have been selected specifically for growth, causing them to develop large pectoral muscles, which interfere with and reduce natural mating. The amount of sperm produced and deposited in the hen's reproductive tract may be limited because of this.

This reaction is important in releasing NADPH. Reduced glutathione is essential for regulation of Mitochondrial membrane permeability and depends on the NADPH generated from the pentose phosphate pathway to be regenerated from oxidized glutathione. Transaldolase plays an important role in male fertility; this is because it maintains the mitochondrial transmembrane potential and its role in the release NADPH. Therefore, transaldolase deficiency decreases the mobility of spermatozoa and lowers male fertility.

Blood products and other human-derived biologics such as breast milk have highly regulated or very hard-to-access markets; therefore, customers generally face a supply shortage for these products. Institutions housing these biologics, designated as 'banks', often cannot distribute their product to customers effectively. Conversely, banks for reproductive cells are much more widespread and available due to the ease with which spermatozoa and egg cells can be used for fertility treatment.

A comparison of the chromosomes of the plains viscacha rat and the mountain viscacha rat suggested that the chromosomes of the plains viscacha rat increased relatively rapidly (in evolutionary terms) due to a diverse set of highly repetitive elements. The animal's spermatozoa are roughly twice normal size, thought to be by virtue of having twice as many sets of chromosomes. The rodent is not a rat, but a caviomorph, kin to guinea pigs and chinchillas.

According to his records, Binneveld could not tell whether she had been raped. He found no evidence of tears or wounds in the vagina other than the lacerations mentioned above. Laboratory analysis of a vaginal smear revealed no spermatozoa present in the vagina, nor any organisms resembling gonococci, which could have been other evidence of sex. There were no other gross signs of bruises, breaks in the skin or other signs of violence.

The lining of these paired, compound, tubuloalveloar glands is simple columnar epithelium. A capsule of dense connective tissue contains some smooth muscle as well as skeletal muscle of the bulbospongiosus and urethral muscles. All domestic species have these glands except the dog, and their mucus secretion serves to clear the urethra of urine and to lubricate it and the vagina. The product may also serve as an energy source for the spermatozoa.

Several hundred glands in the endocervix produce 20–60 mg of cervical mucus a day, increasing to 600 mg around the time of ovulation. It is viscous because it contains large proteins known as mucins. The viscosity and water content varies during the menstrual cycle; mucus is composed of around 93% water, reaching 98% at midcycle. These changes allow it to function either as a barrier or a transport medium to spermatozoa.

Culture of human embryonic stem cells in mitotically inactivated porcine ovarian fibroblasts (POF) causes differentiation into germ cells (precursor cells of oocytes and spermatozoa), as evidenced by gene expression analysis. Human embryonic stem cells have been stimulated to form Spermatozoon-like cells, yet still slightly damaged or malformed. It could potentially treat azoospermia. In 2012, oogonial stem cells were isolated from adult mouse and human ovaries and demonstrated to be capable of forming mature oocytes.

The uniflagellated sperm cells (with one flagellum) of animals are referred to as spermatozoa, and are known to vary in size. Motile sperm are also produced by many protists and the gametophytes of bryophytes, ferns and some gymnosperms such as cycads and ginkgo. The sperm cells are the only flagellated cells in the life cycle of these plants. In many ferns and lycophytes, cycads and ginkgo they are multi-flagellated (carrying more than one flagellum).

Capacitated and hyperactivated sperm respond to these gradients by changing their behaviour and moving towards the cumulus-oocyte complex. Other chemotactic signals such as formyl Met-Leu-Phe (fMLF) may also guide spermatozoa. The zona pellucida, a thick layer of extracellular matrix that surrounds the egg and is similar to the role of the vitelline membrane in sea urchins, binds the sperm. Unlike sea urchins, the sperm binds to the egg before the acrosomal reaction.

The vagina is a fibromuscular (made up of fibrous and muscular tissue) canal leading from the outside of the body to the cervix of the uterus or womb. It is also referred to as the birth canal in the context of pregnancy. The vagina accommodates the male penis during sexual intercourse. Semen containing spermatozoa is ejaculated from the male at orgasm, into the vagina potentially enabling fertilization of the egg cell (ovum) to take place.

Cross section of the epithelium of a seminiferous tubule showing various stages of spermatocyte development Scheme showing analogies in the process of maturation of the ovum and the development of the spermatids (young spermatozoa). Spermatidogenesis is the creation of spermatids from secondary spermatocytes during spermatogenesis. Secondary spermatocytes produced earlier rapidly enter meiosis II and divide to produce haploid spermatids. The brevity of this stage means that secondary spermatocytes are rarely seen in histological preparations.

The protein encoded by this gene belongs to a distinct class of mammalian adenylyl cyclase that is soluble and insensitive to G protein or forskolin regulation. It is localized in the cytoplasm and is thought to function as a general bicarbonate sensor throughout the body. It may also play an important role in the generation of cAMP in spermatozoa, implying possible roles in sperm maturation through the epididymis, capacitation, hypermotility, and/or the acrosome reaction.

R. pachyptila is a dioecious vestimentiferan. Individuals of this species are sessile and are found clustered together around deep-sea hydrothermal vents of the East Pacific Rise and the Galapagos Rift. The size of a patch of individuals surrounding a vent is within the scale of tens of metres. The male's spermatozoa are thread- shaped and are composed of three distinct regions: the acrosome (6 μm), the nucleus (26 μm) and the tail (98 μm).

The development of germ cells can be divided into two phases. The first phases involves the fetal and neonatal phases of germ cell development that lead to the formation of the SSCs. The second phase is spermatogenesis, which is a cycle of regulated mitosis, meiosis and differentiation (via spermiogenesis) leading to the production of mature spermatozoa, also known as sperm cells. Gonocytes are functionally present during the first phase of germ cell maturation and development.

This acacia derivative successfully prevented sperm entry into the cervical mucus, disrupted spermatozoa plasma membrane and disintegrated the acrosomal cap. Today it is understood that the more acidic the vagina is, sperm death is increased due to a hostile environment. A misconception about spermicides existed in the 1980s and 1990s. A 1988 literature review article noted that in vitro studies of nonoxynol-9 and other spermicides showed inactivation of STD pathogens, including HIV.

Kidney disease may develop before or after hyperglycemia, and a significant number of people with MODY5 are discovered in renal clinics. With or without kidney disease, some people with forms of HNF1β have had various minor or major anomalies of the reproductive system. Male defects have included epididymal cysts, agenesis of the vas deferens, or infertility due to abnormal spermatozoa. Affected women have been found to have vaginal agenesis, hypoplastic, or bicornuate uterus.

Spermatozoa can initiate the acrosomal reaction well in advance of reaching the zona pellucida, as well as in vitro in an appropriate culture medium. This is referred to as spontaneous acrosome reaction (SAR). It is now known that in a certain sense, this phenomenon is physiologically normal across mammalian species. The acrosome reaction is induced by passage through the cumulus oophorus cells, mediated by the hormones they secrete (such as progesterone, LPA, LPC).

Herophilus was able to discover and describe not only the salivary glands, but the small intestine and liver. He showed that the uterus is a hollow organ and described the ovaries and uterine tubes. He recognized that spermatozoa were produced by the testes and was the first to identify the prostate gland. The anatomy of the muscles and skeleton is described in the Hippocratic Corpus, an Ancient Greek medical work written by unknown authors.

These snails cling solidly with their broad, muscular foot to rocky surfaces at sublittoral depths, although some species such as Haliotis cracherodii used to be common in the intertidal zone. Abalones reach maturity at a relatively small size. Their fecundity is high and increases with their size, laying from 10,000 to 11 million eggs at a time. The spermatozoa are filiform and pointed at one end, and the anterior end is a rounded head.

In contrast to oogenesis, the production of sperm cells is a lifelong process. Each year after puberty, spermatogonia (precursors of the spermatozoa) divide meiotically about 23 times. By the age of 40, the spermatogonia will have undergone about 660 such divisions, compared to 200 at age 20. Copying errors might sometimes happen during the DNA replication preceding these cell divisions, which may lead to new (de novo) mutations in the sperm DNA.

These hairs were subsequently lost from the prosecution's exhibits and have never been recovered. Spermatozoa recovered from the victim's body had been destroyed – without having been tested to determine whether Brandley could have been its source. Moreover, a fresh blood spot had been found on the victim's blouse that had not come from her and could not have come from Brandley. The spot was Type A, but Brandley had Type O blood.

Micro-TESE, or microdissection testicular sperm extraction, includes the use of an operating microscope. This allows the surgeon to observe regions of seminiferous tubules of the testes that have more chance of containing spermatozoa. The procedure is more invasive than conventional TESE, requiring general anaesthetic, and usually used only in patients with non-obstructive azoospermia. Similarly to TESE, an incision is made in the scrotum and surface of the testicle to expose seminiferous tubules.

Seminiferous tubules are located within the testes, and are the specific location of meiosis, and the subsequent creation of male gametes, namely spermatozoa. The epithelium of the tubule consists of a type of sustentacular cells known as Sertoli cells, which are tall, columnar type cells that line the tubule. In between the Sertoli cells are spermatogenic cells, which differentiate through meiosis to sperm cells. Sertoli cells function to nourish the developing sperm cells.

A disintegrin and metalloprotease 3, or ADAM3, belongs to a family of peptidase proteins referred to as ADAMs. Many of these are solely found in spermatogenic cells, specifically in the anterior portion of capacitated spermatozoa heads. This membrane protein is critical for crucial steps in fertilization such as migration of sperm through the uterus to the oviduct as well as binding to the zona pellucida. Inactivation of ADAM3 is a cause of male infertility.

Is secreted by granulosa cells into the follicular fluid. Glycodelin-F reduces the blinding of spermatozoa to the zona pellucida which is mainly expressed in the ovary, and synthesised in the granulosa cells, has a function in principle similar to that of Glycodelin-A. It also binds the sperm head, thereby inhibiting acrosome reaction and sperm- egg binding. Upon de-glycosilation, glycodelin F dissociates from the sperm and sperm-egg binding is possible.

Spallanzani described animal (mammal) reproduction in his Experiencias Para Servir a La Historia de La Generación De Animales y Plantas (1786). He was the first to show that fertilisation requires both spermatozoa and an ovum. He was the first to perform in vitro fertilization, with frogs, and an artificial insemination, using a dog. Spallanzani showed that some animals, especially newts, can regenerate some parts of their body if injured or surgically removed.

1 µm in diameter. This mycoplasma species was originally isolated from human spermatozoa and a human cervix. It has been rare in humans because it was recovered from only 1 to 2% of the samples examined in two surveys. These initial samples were collected at a fertility clinic where it was noted that either eggs did not become fertilized with infected sperm or fertilized eggs did not implant in in vitro fertilization procedures.

Formation of a temperature gradient in the rabbit’s oviduct at ovulation by a temperature drop at the sperm storage site. The scheme is not drawn to scale, and objects are magnified disproportionally for demonstration purposes. Sperm thermotaxis is a form of sperm guidance, in which sperm cells (spermatozoa) actively change their swimming direction according to a temperature gradient, swimming up the gradient. Thus far this process has been discovered in mammals only.

While the non-mammalian animal egg was obvious, the doctrine ex ovo omne vivum ("every living [animal comes from] an egg"), associated with William Harvey (1578–1657), was a rejection of spontaneous generation and preformationism as well as a bold assumption that mammals also reproduced via eggs. Karl Ernst von Baer discovered the mammalian ovum in 1827. The fusion of spermatozoa with ova (of a starfish) was observed by Oskar Hertwig in 1876.

Calcium ions play a primary role in the regulation of sperm motility. This gene belongs to a family of putative cation channels that are specific to spermatozoa and localize to the flagellum. The protein family features a single repeat with six membrane-spanning segments and a predicted calcium- selective pore region. This gene is part of a tandem repeat on chromosome 15q15; the second copy of this gene is thought to be a pseudogene.

Reproduction 2002;124: 733-743. Another cytometric technique used in sperm sorting is magnetic-activated cell sorting (MACS) which is routinely applied in assisted reproduction hospitals to sort out sperm with fragmented DNA. This is achieved using antibodies to surface markers of programmed cell death (apoptosis) such as annexin V, coupled with magnetic beads. Following the binding of these antibodies, spermatozoa which undergo apoptosis are sorted by applying magnetic field to the sperm suspension.

Conventional methods of sperm sorting have been widely used to assess quality of sperm before subsequent artificial insemination or in-vitro fertilization. It has been verified that sperm sorted using these techniques is of superior quality than unsorted. However, important characteristics of sperm such as DNA integrity remain untested by these conventional methods. New flow-cytometry based techniques such as YO-PRO staining can discriminate apoptotic and dead spermatozoa from the viable ones.

The immature spermatozoa or sperm are then sent to the epididymis, where they gain a tail, enabling motility. Each of the original diploid germ cells or primary spermatocytes forms four functional gametes which is each forever young. The production and survival of sperms require a temperature below the normal core body temperature. Since the scrotum, where the testes is present, is situated outside the body cavity, it provides a temperature about 3 °C below normal body temperature.

Patency of the utero-tubal junction is necessary for normal reproduction. The tubes can get blocked here by infection (salpingitis) and surgical intervention may be necessary. Mouse studies have indicated that selective passage of individual spermatozoa may occur at this junction, with abnormal morphology being identified as a significant selection criterion, leading to predominantly normal sperm passing towards the ovum. Absence of the protein calmegin has also been suggested as a critical factor for reliable sperm passage.

On April 30, 1990, James Harvey was convicted of rape and forcible sodomy by a jury in Fairfax County Circuit Court. He was sentenced to 25 years in prison. One piece of evidence used to convict Harvey was restriction fragment length polymorphism ("RFLP") DNA testing. The victim had two assailants, and this test prevented both Harvey and his co-defendant from being excluded as a possible source of spermatozoa recovered from the victim through conventional serology.

Spermatozoa are produced in the testes of males in a process called spermatogenesis. In order to render a man infertile, a hormone-based male contraceptive method must stop spermatogenesis by interrupting the release of gonadotropins from the pituitary gland. Even in low concentrations, trestolone is a potent inhibitor of the release of the gonadotropins, luteinizing hormone (LH) and follicle stimulating hormone (FSH). In order for spermatogenesis to occur in the testes, both FSH and testosterone must be present.

It is called zona pellucida in mammals. As soon as the spermatozoon fuses with the ovum, signal transduction occurs, resulting in an increase of cytoplasmic calcium ions. This itself triggers the cortical reaction, which results in depositing several substances onto the vitelline membrane through exocytosis of the cortical granules, transforming it into a hard layer called the “fertilization membrane”, which serves as a barrier inaccessible to other spermatozoa. This phenomenon is the slow block to polyspermy.

Ticks can also become infected with R. rickettsii while feeding on blood from the host in either the larval or nymphal stage. After the tick develops into the next stage, the R. rickettsii may be transmitted to the second host during the feeding process. Furthermore, male ticks may transfer R. rickettsii to female ticks through body fluids or spermatozoa during the mating process. These types of transmission represent how generations or life stages of infected ticks are maintained.

Males are more aggressive in their pre-mating competition when in the presence of immature females than when competing for a sexually mature female. Most cephalopod males develop a hectocotylus, an arm tip which is capable of transferring their spermatozoa into the female mantel cavity. Though not all species use a hectocotylus; for example, the adult nautilus releases a spadix. An indication of sexual maturity of females is the development of brachial photophores to attract mates.

The fur on the scrotum completely falls off and does not grow back, even if the male survives months after the first mating season. As the marsupial ages, its testicles grow until they reach a peak size and weight at the beginning of the mating season. After the individual mates, the weight and size of the testes and scrotum decrease. They remain small and do not produce spermatozoa later in life, if maintained in a laboratory.

Sperm guidance in non-mammalian species is performed by chemotaxis. The oocyte secretes a chemoattractant, which, as it diffuses away, forms a concentration gradient: a high concentration close to the egg, and a gradually lower concentration as the distance from the oocyte increases. Spermatozoa can sense this chemoattractant and orient their swimming direction up the concentration gradient towards the oocyte. Sperm chemotaxis was demonstrated in a large number of non-mammalian species, from marine invertebrates to frogs.

In humans, there are at least two different origins of sperm chemoattractants. One is the cumulus cells that surround the oocyte, and the other is the mature oocyte itself. The chemoattractant secreted from the cumulus cells is the steroid progesterone, shown to be effective at the picomolar range.Teves, M.E., Barbano, F., Guidobaldi, H.A., Sanchez, R., Miska, W. and Giojalas, L.C. (2006) Progesterone at the picomolar range is a chemoattractant for mammalian spermatozoa. Fertil. Steril. 86, 745–749.

The molecular mechanism underlying thermotaxis, in general, and thermosensing with such extreme sensitivity, in particular, is obscure. It is known that, unlike other recognized thermosensors in mammals, the thermosensors for sperm thermotaxis do not seem to be temperature-sensitive ion channels. They are rather opsins, known to be G-protein-coupled receptors that act as photosensors in vision. The opsins are present in spermatozoa at specific sites, which depend on the species and the opsin type.

50, 786–790. These sperm features raised the possibility that prolonging the time period, during which capacitated spermatozoa can be found in the female genital tract, is a mechanism, evolved in humans, to compensate for the lack of coordination between insemination and ovulation.Giojalas, L.C., Rovasio, R.A., Fabro, G., Gakamsky, A. and Eisenbach, M. (2004) Timing of sperm capacitation appears to be programmed according to egg availability in the female genital tract. Fertil. Steril. 82, 247–249.

However, sperm are not free to produce,Olsson et al., 1997; Wedell et al., 2002 and as such males are predicted to produce sperm of a size and number that will maximize their success in sperm competition. By making many spermatozoa, males can buy more "raffle tickets", and it is thought that selection for numerous sperm has contributed to the evolution of anisogamy with very small sperm (because of the energy trade-off between sperm size and number).

They are contractile cells which contain actin filaments and are primarily involved in transport of spermatozoa through the tubules. They provide structural integrity to the tubules through their involvement in laying down the basement membrane. This has also been shown to affect Sertoli cell function and PTM cells also communicate with Sertoli cells through the secretion of growth factors and ECM (extra-cellular matrix) components. Studies have shown PTM cells to be critical in achieving normal spermatogenesis.

The cremaster muscle's function is to raise and lower the testes in order to regulate scrotal temperature for optimal spermatogenesis and survival of the resultant spermatozoa. It does this by increasing or decreasing the exposed surface area of the surrounding tissue, allowing faster or slower dissipation of body heat. The cremaster muscle is an involuntary muscle and contraction can occur during arousal which can prevent injury to the testicles during sex. Contraction also occurs during ejaculation.

This gene encodes a histone H1 binding protein that is involved in transporting histones into the nucleus of dividing cells. The somatic form is expressed in all mitotic cells, is localized to the nucleus, and is coupled to the cell cycle. The testicular form is expressed in embryonic tissues, tumor cells, and the testis. In male germ cells, this protein is localized to the cytoplasm of primary spermatocytes, the nucleus of spermatids, and the periacrosomal region of mature spermatozoa.

This results in a loss of nutrition for the crab, and impairs its overall growth. The natural ability of regrowing a severed claw that is commonly used for defense purposes is therefore lost after the infestation of Sacculina. The male Sacculina 'larva' looks for a virgin female Sacculina on the underside of a crab. He then implants its cells into a pocket in the female's body called the "testis", where male cells produce spermatozoa to fertilize eggs.

SLC45A4 is a member of the SLC45 family of solute carriers. Analysis of the protein function in a recombinant yeast expression assay show that it can: (i) transport a disaccharide,sucrose, as well simple sugars such as glucose and fructose (ii) perform secondary active transport in a proton-dependent manner. It is associated with sugar transport in the spermatozoa. Additionally, it has been itdentified as a necessary component in the cell death caused of the compound paraquat.

Starting in 1992 and continuing until 2015 (when he handed over to a steering group) Birkhead organised (with Professor Harry Moore) a small (~60) biennial meeting on reproductive biology in the Peak District National Park known as Biology of Spermatozoa (BoS). Delegates are from a diverse range of backgrounds and include clinicians, reproductive physiologists, andrologists, theoreticians and evolutionary biologists. The format and interdisciplinary nature of the meeting was successful in terms of exchanging ideas, techniques and establishing collaborations.

A Texas blind salamander The time of breeding is poorly documented. Dunn (1926) noted a specimen maintained in the laboratory laid a few eggs on March 15 and a specimen collected in early fall had the spermatheca packed with spermatozoa. Very small juveniles have been found throughout the year, suggesting a seasonal breeding pattern. Bechler (1988) observed one complete and two partial courtship bouts in captive specimens in which the female initiated courtship and the male remained passive initially.

The molecular mechanism underlying thermotaxis, in general, and thermosensing with such extreme sensitivity, in particular, is obscure. It is known that, unlike other recognized thermosensors in mammals, the thermosensors for sperm thermotaxis do not seem to be temperature- sensitive ion channels. They are rather opsins, known to be G-protein-coupled receptors that act as photosensors in vision. The opsins are present in spermatozoa at specific sites, which depend on the species and the opsin type.

Spermatozoa can be considered morphologically suitable for ICSI procedures when the sperm head is regular oval, symmetric and with smooth appearance. it should be 4.5-4.9 μm in length and 3.1-3.5 μm. Nuclear chromatin mass should be homogeneous, with no more than one vacuole, or with a total vacuolar area of less than 4% of nuclear area. also the central part has to be of a normal rectangular shape between 4.0 and 5.0 μm in length.

The acrosome is an organelle that develops over the anterior half of the head in the spermatozoa (sperm cells) of many animals including humans. It is a cap-like structure derived from the Golgi apparatus. In Eutherian mammals the acrosome contains digestive enzymes (including hyaluronidase and acrosin). These enzymes break down the outer membrane of the ovum, called the zona pellucida, allowing the haploid nucleus in the sperm cell to join with the haploid nucleus in the ovum.

His body of work includes The Cell and Molecular Biology of Fish Oogenesis, Cellular and Molecular Biology of Gonadal Development and Maturation in Mammals: Fundamentals and Biomedical Implications, Comparative Cellular and Molecular Biology of Ovary in Mammals: Fundamental and Applied Aspects, Comparative Cellular and Molecular Biology of Testis in Vertebrates: Trends in Endocrine, Paracrine, and Autocrine Regulation of Structure and Functions, Cellular And Molecular Biology For Human, (all on Cell and Molecular biology), Biology of Spermatogenesis and Spermatozoa in Mammals, Biology of Spermatogenesis and Spermatozoa in Mammals, Buffalo bull semen: morphology, biochemistry, physiology and methodology (all on spermatogenesis) and Rodents: ecology, biology and control. He was associated with national and international organizations such as World Health Organization, UNESCO, Indian Council of Medical Research, Indian Council of Agricultural Research, Council of Scientific and Industrial Research and the University Grants Commission and served as the member of the council of Indian National Science Academy (INSA) from 1986 to 1988. He was also a member of the editorial boards of Journal of Biosciences, Himalayan Journal of Environment and Zoology and the journals of the INSA.

The enzyme is a hexamer and displays a two- domain fold, composed of a catalytic (beta/alpha)(8)-like domain and a C-terminal beta-sandwich domain. Drosophila melanogaster spermatozoa contains an alpha-l-fucosidase that might be involved in fertilisation by interacting with alpha-l-fucose residues on the micropyle of the eggshell. In human sperm, membrane-associated alpha-l-fucosidase is stable for extended periods of time, which is made possible by membrane domains and compartmentalisation. These help preserve protein integrity.

GLUT8 function in vivo remains to be defined, despite suggestions that it may play a role in fertility, being expressed at high levels in testes and in the acrosomal part of spermatozoa. Furthermore, GLUT8 appears to play an important role in the energy metabolism of sperm cells. The recent description of GLUT8 expression in kidneys and liver suggest that the transporter may play a role in glucose uptake in these organs. GLUT8, when expressed in Xenopus oocytes, mediates glucose uptake with high affinity.

377–387 Acrosin regulation has been found to occur through protein C inhibitor (PCI). PCI is present in the male reproductive tract at 40x higher concentrations than in blood plasma. PCI has been demonstrated to inhibit the proteolytic activity of acrosin. Thus, PCI has been hypothesized to have a protective role: if acrosomal enzymes were released prematurely, or if the spermatozoa was degenerated within the male reproductive tract, the high concentrations of PCI would inhibit acrosin from inflicting proteolytic damage on nearby tissues.

The cortical reaction occurs due to calcium oscillations inside the oocyte. What triggers such oscillations is PLC-zeta, a phospholipase unique to sperm that is very sensitive to calcium concentrations. When the first spermatozoa get inside the oocyte, it brings in PLC-zeta, that is activated by oocyte's basal calcium concentrations, initiates the formation of IP3 and causes calcium release from endoplasmic reticulum stores, generating the oscillations in calcium concentration that will activate the oocyte and block polyspermy.Miao, YL & Williams CJ. 2012.

In the newt species Notophthalmus viridescens, the males rub off hormonal secretions onto the skin of the females they are courting. These hormones have been shown to make the female more receptive to mating with the male. When the male deposits the secretions, he detaches from the female and releases a spermatophore (containing spermatozoa). It is then the female's decision to either accept it and pick it up or reject it by running away; these hormones make her more likely to accept it.

Biology began to quickly develop and grow with Anton van Leeuwenhoek's dramatic improvement of the microscope. It was then that scholars discovered spermatozoa, bacteria, infusoria and the diversity of microscopic life. Investigations by Jan Swammerdam led to new interest in entomology and helped to develop the basic techniques of microscopic dissection and staining. Advances in microscopy also had a profound impact on biological thinking. In the early 19th century, a number of biologists pointed to the central importance of the cell.

As the spermatozoa pass through the flow cytometer in single file, each spermatozoon is encased by a single droplet of fluid and assigned an electric charge corresponding to its chromosome status (e.g. X-positive charge, Y-negative charge). The stream of X- and Y- droplets is then separated by means of electrostatic deflection and collected into separate collection tubes for subsequent processing. Recently, a study published in 2006 indicated that mothers with toxoplasmosis have a significantly higher sex ratio of boys to girls.

Females have the ability to store multiple spermatophores until they are needed for fertilization. Sperm storage leads to the post-copulatory sexual selection process of cryptic female choice, which occurs when a female removes the deposited sperm or favors one set of spermatophore over another, during or after copulation. Spermatophores are composed of a cap containing the spermatozoa and a gelatinous support arrangement which fastens the spermatophore to a substrate. Spermatophores are very central to reproductive success; therefore, they are handled carefully.

Calcium-binding tyrosine phosphorylation-regulated protein is a protein that in humans is encoded by the CABYR gene. To reach fertilization competence, spermatozoa undergo a series of morphological and molecular maturational processes, termed capacitation, involving protein tyrosine phosphorylation and increased intracellular calcium. The protein encoded by this gene localizes to the principal piece of the sperm flagellum in association with the fibrous sheath and exhibits calcium-binding when phosphorylated during capacitation. A pseudogene on chromosome 3 has been identified for this gene.

A motile sperm organelle morphology examination (MSOME) is a particular morphologic investigation wherein an inverted light microscope equipped with high-power optics and enhanced by digital imaging is used to achieve a magnification above x6000, which is much higher than the magnification used habitually by embryologists in spermatozoa selection for intracytoplasmic sperm injection (x200 to x400). A potential finding on MSOME is the presence of sperm vacuoles, which are associated with sperm chromatin immaturity, particularly in the case of large vacuoles.

Annu Rev Cell Biol 4, 649–86.). In the best-studied species, sea urchin, the spermatozoa sense a temporal gradient and respond to it with a transient increase in flagellar asymmetry. The outcome is a turn in the swimming path, followed by a period of straight swimming,Kaupp, U.B., Solzin, J., Hildebrand, E., Brown, J.E., Helbig, A., Hagen, V., Beyermann, M., Pampaloni, F. and Weyand, I. (2003) The signal flow and motor response controlling chemotaxis of sea urchin sperm. Nature Cell Biol.

These sperm features raised the possibility that prolonging the time period, during which capacitated spermatozoa can be found in the female genital tract, is a mechanism, evolved in humans, to compensate for the lack of coordination between insemination and ovulation.Giojalas, L.C., Rovasio, R.A., Fabro, G., Gakamsky, A. and Eisenbach, M. (2004) Timing of sperm capacitation appears to be programmed according to egg availability in the female genital tract. Fertil. Steril. 82, 247–249. Chemotaxis is a short-range guidance mechanism.

J. Reprod. Dev., 59, 59-65. and a gradient of natriuretic peptide precursor A, shown to be a chemoattractant for mouse spermatozoa, was found, in decreasing concentration order, in the ampulla, isthmus, and uterotubal junction.Bian, F., Mao, G., Guo, M., Mao, G., Wang, J., Li, J., Han, Y., Chen, X., Zhang, M. and Xia, G. (2012) Gradients of natriuretic peptide precursor A (NPPA) in oviduct and of natriuretic peptide receptor 1 (NPR1) in spermatozoon are involved in mouse sperm chemotaxis and fertilization.

Annu Rev Cell Biol 4, 649–86.). In the best-studied species, sea urchin, the spermatozoa sense a temporal gradient and respond to it with a transient increase in flagellar asymmetry. The outcome is a turn in the swimming path, followed by a period of straight swimming,Kaupp, U.B., Solzin, J., Hildebrand, E., Brown, J.E., Helbig, A., Hagen, V., Beyermann, M., Pampaloni, F. and Weyand, I. (2003) The signal flow and motor response controlling chemotaxis of sea urchin sperm. Nature Cell Biol.

In cases of infertility due to nonobstructive azoospermia, surgical sperm retrieval for IVF-ICSI is successful 40-60% of the time without prior knowledge of the geography of testis sperm production.Tournaye H, Liu J, Nagy PZ, Camus M, Goossens A, Silber S, Van Steirtegham AC, Devroey P. Correlation between testicular histology and outcome after intracytoplasmic sperm injection using testicular spermatozoa. Hum Reprod 1996;11:127-132. With the addition of diagnostic FNA mapping, the rate of successful sperm retrieval can be increased substantially.

These cuboidal granulosa cells, also known as the granulosa radiata, form more layers throughout the maturation process, and remain attached to the zona pellucida after the ovulation of the Graafian follicle. For fertilization to occur, sperm cells rely on hyaluronidase (an enzyme found in the acrosome of spermatozoa) to disperse the corona radiata from the zona pellucida of the secondary (ovulated) oocyte, thus permitting entry into the perivitelline space and allowing contact between the sperm cell and the nucleus of the oocyte.

DAZ is not absolutely required for spermatogenesis as some DAZ deleted men are still able to father children. DAZ pushes ESCs in to germ cells with molecular features of being spermatids. DAZL is expressed in humans from early progenitor germ cell migration, right up to spermatozoa differentiation. Since DAZL is located on an autosome, it has been shown to be important in germ cell development of both oocyte and spermatocytes (in spermatogenesis and oogenesis), albeit in different expression patterns for both.

Schematic two-dimensional cross-sectional view of glycogen: A core protein of glycogenin is surrounded by branches of glucose units. The entire globular granule may contain around 30,000 glucose units. A view of the atomic structure of a single branched strand of glucose units in a glycogen molecule. Glycogen (black granules) in spermatozoa of a flatworm; transmission electron microscopy, scale: 0.3 µm Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria.

However, transport of the mature spermatozoa through the remainder of the male reproductive system is achieved via muscle contraction rather than the spermatozoon's motility. A glycoprotein coat over the acrosome prevents the sperm from fertilizing the egg prior to traveling through the male and female reproductive tracts. Capacitation of the sperm by the enzymes FPP (fertilization promoting peptide, produced in the prostate gland) and heparin (in the female reproductive tract) removes this coat and allows sperm to bind to the egg.

The underparts are white or very pale grey, with a clear dividing line from the fur elsewhere on the body. The head is robust, with a heavy snout. Females have three pairs of teats. Although red rock rats can be distinguished from most other species of the genus Aethomys by their size or bodily proportions, they appear essentially identical to Tete veld rats, and can only be reliably distinguished from them by genetic analysis or examination of the shape of their spermatozoa.

All animals are posited by biologists to have evolved from a flagellated eukaryote. Their closest known living relatives are the choanoflagellates – collared flagellates whose cell morphology is similar to the choanocyte cells of certain sponges. Molecular studies place animals in a supergroup called the opisthokonts, which also include the choanoflagellates, fungi, and a few small parasitic protists. The name comes from the posterior location of the flagellum in motile cells, such as most animal spermatozoa, whereas other eukaryotes tend to have anterior flagella.

This is because of the female's oestrous cycle; as with most large mammals, male hippo spermatozoa is active year-round. Studies of hippos in Zambia and South Africa also showed evidence of births occurring at the start of the wet season. After becoming pregnant, a female hippo will typically not begin ovulation again for 17 months. Preserved hippopotamus fetus Mating occurs in the water, with the female submerged for most of the encounter, her head emerging periodically to draw breath.

A significant contribution came from Antonie van Leeuwenhoek who achieved up to 300 times magnification using a simple single lens microscope. He sandwiched a very small glass ball lens between the holes in two metal plates riveted together, and with an adjustable-by-screws needle attached to mount the specimen. Then, Van Leeuwenhoek re-discovered red blood cells (after Jan Swammerdam) and spermatozoa, and helped popularise the use of microscopes to view biological ultrastructure. On 9 October 1676, van Leeuwenhoek reported the discovery of micro-organisms.

An erection is the stiffening and rising of the penis, which occurs during sexual arousal, though it can also happen in non-sexual situations. Ejaculation is the ejecting of semen from the penis and is usually accompanied by orgasm. A series of muscular contractions delivers semen, containing male gametes known as sperm cells or spermatozoa, from the penis. The most common form of genital alteration is circumcision, the removal of part or all of the foreskin for various cultural, religious, and more rarely medical reasons.

An abstinence period of only 1 or 2 days produce the highest pregnancy rates per IUI cycle compared with longer intervals of ejaculatory abstinence. This increase in pregnancy rate occurs despite a lower value of total motile spermatozoa. Daily sexual activity increases sperm quality in men minimizing DNA damage in the sperm—because it is speculated to result in less storage time where damage may accumulate.Study: Daily sex helps to reduce sperm DNA damage and improve fertility the European Society of Human Reproduction and Embryology (ESHRE).

If the seminal-vesicles contain spermatozoa, but the semen does not, the obstruction must be downstream of the seminal vesicles and the ejaculatory ducts are very likely to be obstructed, provided that other causes for a dry ejaculation/aspermia such as a retrograde ejaculation are ruled out. Attempts are sometimes made to diagnose an ejaculatory duct obstruction by means of medical imaging, e.g. transrectal ultrasound or MRI, or by transrectal needle-aspiration of the seminal vesicles. However transrectal ultrasound has a relatively low sensitivity of approx.

Bactrian camels are induced ovulators — they ovulate after insemination (insertion of semen into the vagina); the seminal plasma, not the spermatozoa, induces ovulation. Ovulation occurs in 87% of females after insemination: 66% ovulate within 36 h and the rest by 48 h (the same as natural mating). The least amount of semen required to elicit ovulation is about 1.0 ml. A mother with a calf Males during mating time are often quite violent and may bite, spit, or attempt to sit on other male camels.

The testes are covered by a tough membranous shell called the tunica albuginea. Within the testes are very fine coiled tubes called seminiferous tubules. The tubules are lined with a layer of cells (germ cells) that develop from puberty through old age into sperm cells (also known as spermatozoa or male gametes). The developing sperm travel through the seminiferous tubules to the rete testis located in the mediastinum testis, to the efferent ducts, and then to the epididymis where newly created sperm cells mature (see spermatogenesis).

Furthermore, the basal Sertoli-Sertoli cell junctions and the apical Sertoli-germ cell junctions contain myosin VIIA but lack its counterpart vezatin. Myosin VIIA is almost always expressed with vezatin but the absence of this partnership within the testis is yet to be fully understood. However, vezatin has been shown to be expressed within the acrosomal region of the actual spermatozoa. Vezatin is not found in the early spermatid but only appears when the formation of the acrosome occurs later on in the process of spermatogenesis.

Self-renewal of spermatogonial stem cells (SSCs) is regulated by local signals. Around 50% of the SSC population undergo self-renewal to maintain stem cell numbers, and the other 50% become committed progenitor cells that will differentiate into spermatozoa during spermatogenesis. Cells present in the testes express molecules that play key roles in the regulation of SSC self-renewal. In mice, Sertoli cells have been shown to secrete Glial cell line-derived neurotrophic factor (GDNF) which has a stimulatory effect on stem cell self-renewal.

Azoospermia factor (AZF) refers to one of several proteins or their genes, which are coded from the AZF region on the human male Y chromosome. Deletions in this region are associated with inability to produce sperm. Subregions within the AZF region are AZFa (sometimes AZF1), AZFb and AZFc (together referred to as AZF2). AZF microdeletions are one of the major causes of male infertility for azoospermia (complete absence of sperm in the ejaculate) and severe oligozoospermia (less than 5 million spermatozoa in the ejaculate) males.

With the granting of a fellowship, he attended the University of Chicago where he was awarded his Ph.D. in 1916, with a thesis on the fertilization and parthenogenesis in sea urchin eggs. He became an associate in the university's zoology department from 1916-1918, then an instructor, a full professor in 1928 and chairman of the department in 1934. He was married to Edith Naomi Abernethy in 1920. Carl Moore is noted for his studies of the reproductive tract of male mammals and the physiology of spermatozoa.

A Sertoli cell (a kind of sustentacular cell) is a "nurse" cell of the testicles that is part of a seminiferous tubule and helps in the process of spermatogenesis, the production of sperm. It is activated by follicle- stimulating hormone (FSH) secreted by the adenohypophysis, and has FSH receptor on its membranes. It is specifically located in the convoluted seminiferous tubules (since this is the only place in the testes where the spermatozoa are produced). Development of Sertoli cells is directed by the testis-determining factor protein.

The exact life span of an adult worm is not determined; however, evidences from an outbreak among British military in the 1930s indicate that they can survive 2 to 5 years in humans. As a hermaphrodite, it reproduces by self-fertilisation, or cross- fertilisation if gametes are exchanged between two different proglottids. Spermatozoa fuse with the ova in the fertilisation duct, where the zygotes are produced. The zygote undergoes holoblastic and unequal cleavage resulting in three cell types, small, medium and large (micromeres, mesomeres, megameres).

After liquefaction, the viscosity of the sample can be estimated by gently aspirating into a wide-bore (approximately 1,5 mm of diameter) plastic disposable pipette, allowing the semen to drop by gravity and observing the length of any thread. A normal sample leaves the pipette in small discrete drops. If viscosity is abnormal, the drop will form a thread more than 2 cm long. High viscosity can interfere with determination of sperm motility, sperm concentration, detection of antibody-coated spermatozoa and measurement of biochemical markers.

Fabro, G., Rovasio, R.A., Civalero, S., Frenkel, A., Caplan, S.R., Eisenbach, M. and Giojalas, L.C. (2002) Chemotaxis of capacitated rabbit spermatozoa to follicular fluid revealed by a novel directionality-based assay. Biol. Reprod. 67, 1565–1571. Indeed, due to obvious restrictions, all these mechanisms were demonstrated in vitro only. However, the discoveries of proper stimuli in the female – an ovulation-dependent temperature gradient in the oviduct,David A, Vilensky A, Nathan H. (1972) Temperature changes in the different parts of the rabbit's oviduct. Int.

It has been shown that epithelial sodium channel ENaC that allows the flow of Na+ ions into the cell is localized on stereocilia. Because sperm are initially non-motile as they leave the seminiferous tubules, large volumes of fluid are secreted to propel them to the epididymis. The core function of the stereocilia is to resorb 90% of this fluid as the spermatozoa start to become motile. This absorption creates a fluid current that moves the immobile sperm from the seminiferous tubules to the epididymis.

Spermatozoa formed in the testis enter the caput epididymis, progress to the corpus, and finally reach the cauda region, where they are stored. Sperm entering the caput epididymis are incomplete—they lack the ability to swim forward (motility) and to fertilize an egg. Epididymal transit takes about 2.5 months in humans (longer in other species), but the sperm can be stored in the cauda for 2–3 days. During their transit in the epididymis, sperm undergo maturation processes necessary for them to acquire motility and fertility.

The method for SMGT uses the sperm cell, a natural vector of genetic material, to transport exogenous DNA. The exogenous DNA molecules bind to the cell membrane of the head of the sperm cell. This binding and internalization of the DNA is not a random event. The exogenous DNA interacts with the DNA-binding proteins (DBPs) that are present on the surface of the sperm cell.3 Spermatozoa are naturally protected against the intrusion of exogenous DNA molecules by an inhibitory factor present in mammals’ seminal fluid.

The length of maturity for males and females differ with males ranging from 185 to 1250 mm in total length and females ranging from 243 to 1368 mm in total length. Males have a continuous production of mature spermatozoa suggests they can reproduce throughout the year but studies have shown higher values in certain months but they are not significant. Females also reproduce year-round with peaks of reproductive activity as well. Female spotback skates lay their eggs on the ocean floor and leave them there.

In humans, 50% of infertility issues are caused by males, and of this, genetic deletions in the Y chromosome make up a lot of this majority, since only men have the Y chromosome. DAZ gene in present on Y chromosome and deletion of this gene has been directly shown as a main cause of infertility. This causes no sperm cell found in semen and it is termed Azoospermia. One DAZ homologue is expressed in nearly every stage of spermatogenesis, from Primordial Germ Cells (PGCs) to mature spermatozoa.

These researchers produced primordial germ cell-like cells (PGLCs) from embryonic stem cells (ESCs) and skin cells in vitro. Hayashi and Saitou's group was able to promote the differentiation of embryonic stem cells into PGCs with the use of precise timing and bone morphogenetic protein 4 (Bmp4). Upon succeeding with embryonic stem cells, the group was able to successfully promote the differentiation of induced pluripotent stem cells (iPSCs) into PGLCs. These primordial germ cell-like cells were then used to create spermatozoa and oocytes.

The zona pellucida is an extracellular matrix that surrounds the oocyte and early embryo. It is composed primarily of three (mouse) or four (human) glycoproteins (ZP1-4) with various functions during fertilization and preimplantation development. The protein encoded by this gene is a structural component of the zona pellucida and functions in secondary binding and penetration of acrosome-reacted spermatozoa. The nascent protein contains a N-terminal signal peptide sequence, a conserved ZP domain, a consensus furin cleavage site, and a C-terminal transmembrane domain.

This is not very feasible in most cases due to the inability of the couple to always stay together. Another form of mate guarding which is more common is for the male to increase in-pair copulations by increasing the females store of spermatozoa and further increasing his likelihood of paternity. Mate guarding is energetically costly and can be adjusted based on the risk of cuckoldry as seen in the Seychelles warbler. Mate guarding behavior is negatively correlated with foraging behavior and body condition.

The female insect's main reproductive function is to produce eggs, including the egg's protective coating, and to store the male spermatozoa until egg fertilisation is ready. The female reproductive organs include paired ovaries which empty their eggs (oocytes) via the calyces into lateral oviducts, joining to form the common oviduct. The opening (gonopore) of the common oviduct is concealed in a cavity called the genital chamber and this serves as a copulatory pouch (bursa copulatrix) when mating. The external opening to this is the vulva.

Some humans have very low levels of catalase (acatalasia), yet show few ill effects. The increased oxidative stress that occurs with aging in mice is alleviated by over-expression of catalase. Over-expressing mice do not exhibit the age-associated loss of spermatozoa, testicular germ and Sertoli cells seen in wild-type mice. Oxidative stress in wild-type mice ordinarily induces oxidative DNA damage (measured as 8-oxodG) in sperm with aging, but these damages are significantly reduced in aged catalase over-expressing mice.

The final chromosomes in the two human gametes are called sex chromosomes because of their role in sex determination. Ova always have the same sex chromosome, labelled X. About half of spermatozoa also have this same X chromosome, the rest have a Y-chromosome. At fertilization the gametes fuse to form a cell, usually with 46 chromosomes, and either XX female or XY male, depending on whether the sperm carried an X or a Y chromosome. Some of the other possibilities are listed above.

Fellatio cannot result in pregnancy, as there is no way for ingested sperm to reach the uterus and fallopian tubes to fertilize an egg. At any rate, acids in the stomach and digestive enzymes in the digestive tract break down and kill spermatozoa. Clinical research has tentatively linked fellatio with immune modulation, indicating it may reduce the chance of complications during pregnancy. The potentially fatal complication pre-eclampsia was observed to occur less in women who regularly engaged in fellatio, with those who also ingested their partner's semen being at the least risk.

Fertilization: a sperm's journey to and interaction with the oocyte. The Journal of clinical investigation, 120(4), 984-94.. In-vitro human experiments have also been conducted, suggesting that Izumo is required for human gamete fusion. [1] Through the use of Western Blot analyses, it has been shown that Izumo is only expressed in the testis and is found on mature spermatozoa. Ellerman DA, Pei J, Gupta S, Snell WJ, Myles D, Primakoff P. Izumo is part of a multiprotein family whose members form large complexes on mammalian sperm.

In this sense there are three types of life cycles that utilize sexual reproduction, differentiated by the location of the organism phase(s). In the diplontic life cycle (with pre-gametic meiosis), of which humans are a part, the organism is diploid, grown from a diploid cell called the zygote. The organism's diploid germ-line stem cells undergo meiosis to create haploid gametes (the spermatozoa for males and ova for females), which fertilize to form the zygote. The diploid zygote undergoes repeated cellular division by mitosis to grow into the organism.

Animation of the migration of spermatozoa from their origin as germ cells to their exit from the vas deferens. A.) Blood vessels; B.) Head of epididymis; C.) Efferent ductules; D.) Seminiferous tubules; E.) Parietal lamina of tunica vaginalis; F.) Visceral lamina of tunica vaginalis; G.) Cavity of tunica vaginalis; H.) Tunica albuginea; I.) Lobule of testis; J.) Tail of epididymis; K.) Body of epididymis; L.) Mediastinum; M.) Vas deferens. Testicle or testis (plural testes) is the male reproductive gland or gonad in all animals, including humans. It is homologous to the female ovary.

One of the major known substances driving the differentiation of SSCs, and therefore the production of spermatozoa, is Retinoic Acid (RA). There are theories supporting the hypotheses of both an indirect (via Sertoli cells) or a direct pathway. It is thought that Sertoli cells produce RA through the conversion of circulating retinol to retinal and then finally to RA. Exposure to RA drives cellular differentiation into A1 spermatogonia and is implicated in further meiotic differentiation. As a result of differentiation, the genes required to maintain a SSC state are no longer expressed.

PSA was first identified by researchers attempting to find a substance in seminal fluid that would aid in the investigation of rape cases. PSA is now used to indicate the presence of semen in forensic serology. The semen of adult males has PSA levels far in excess of those found in other tissues; therefore, a high level of PSA found in a sample is an indicator that semen may be present. Because PSA is a biomarker that is expressed independently of spermatozoa, it remains useful in identifying semen from vasectomized and azoospermic males.

In particular, the extraperitoneal location of the testes may result in a 2-fold reduction in the heat-induced contribution to the spontaneous mutation rate in male germinal tissues compared to tissues at 37 °C. If the testicles remain too close to the body, it is likely that the increase in temperature will harm the spermatozoa formation, making conception more difficult. This is why the testes are carried in an external pouch viz. scrotum rather than within the abdomen; they normally remain slightly cooler than body temperature, facilitating sperm production.

The gonopodium has a channel-like structure through which bundles of spermatozoa, called spermatozeugmata, are transferred to females. In courted mating, where the female shows receptive behavior following the male's courtship display, the male briefly inserts the gonopodium into the female's genital pore for internal fertilization. However, in the case of sneaky mating where copulation is forced, the male approaches the female and thrusts the gonopodium at the female's urogenital pore. Once inseminated, female guppies can store sperm in their ovaries and gonoducts, which can continue to fertilize ova up to eight months.

In 1996, after having served 5 years in prison for a rape conviction, Douglas Echols read about the Innocence Project, a non-profit organization dedicated to freeing the wrongfully convicted. Although Echols had been released from prison, his charges had not been cleared. The Innocence Project agreed to take on his case and, in February 2001, finally got permission to do DNA testing on the rape kit evidence. In July 2001, extensive DNA testing of Echols and co- defendant Samuel Scott showed that they could not have contributed the spermatozoa from the vaginal swabs.

Even within humans and other mortal species, there are cells with the potential for immortality: cancer cells which have lost the ability to die when maintained in a cell culture such as the HeLa cell line, and specific stem cells such as germ cells (producing ova and spermatozoa). In artificial cloning, adult cells can be rejuvenated to embryonic status and then used to grow a new tissue or animal without aging. Normal human cells however die after about 50 cell divisions in laboratory culture (the Hayflick Limit, discovered by Leonard Hayflick in 1961).

As a result, the animals absorb liquid, begin to swell, and separate from the substrate so that they float freely in the water. In the protected interior space, the ventral cells form an ovum surrounded by a special envelope, the fertilisation membrane; the ovum is supplied with nutrients by the surrounding syncytium, allowing energy-rich yolk to accumulate in its interior. Once maturation of the ovum is complete, the rest of the animal degenerates, liberating the ovum itself. Small unciliated cells that form at the same time are interpreted to be spermatozoa.

Production takes place in the testes which are housed in the temperature regulating scrotum, immature sperm then travel to the epididymis for development and storage. The second category are the ejaculatory fluid producing glands which include the seminal vesicles, prostate, and the vas deferens. The final category are those used for copulation, and deposition of the spermatozoa (sperm) within the male, these include the penis, urethra, vas deferens, and Cowper's gland. Major secondary sexual characteristics includes: larger, more muscular stature, deepened voice, facial and body hair, broad shoulders, and development of an Adam's apple.

A major focus of the book is sperm heteromorphism, in which not only are a variety of morphological typesBelsey, M.A. et al. (1987) WHO Laboratory Manual for Examination of Human Semen and Semen-Cervical Mucus Interaction. 2nd edn, Cambridge University Press, Cambridge of sperm apparent in every normal human ejaculate, but also at any one time fewer than 1% seem capable of responding to and fertilizing an egg.Quinn, P. & Marrs, R.P. (1991) Effect of concentration and total number of spermatozoa on fertilizationof human oocytes in vitro. Hum. Reproduc. 6, Suppl.

In the prostate, this reduces prostate volume, which improves BPH and reduces risk of prostate cancer. Finasteride reduces prostate volume by 20 to 30% in men with benign prostatic hyperplasia. Inhibition of 5α-reductase also reduces epididymal weight, and decreases motility and normal morphology of spermatozoa in the epididymis. Neurosteroids like 3α-androstanediol (derived from DHT) and allopregnanolone (derived from progesterone) activate the GABAA receptor in the brain; because finasteride prevents the formation of neurosteroids, it functions as a neurosteroidogenesis inhibitor and may contribute to a reduction of GABAA activity.

Regarding sperm morphology, the WHO criteria as described in 2010 state that a sample is normal (samples from men whose partners had a pregnancy in the last 12 months) if 4% (or 5th centile) or more of the observed sperm have normal morphology. Morphology is a predictor of success in fertilizing oocytes during in vitro fertilization. Up to 10% of all spermatozoa have observable defects and as such are disadvantaged in terms of fertilising an oocyte. Also, sperm cells with tail-tip swelling patterns generally have lower frequency of aneuploidy.

With a straw or a vial volume of 0.5 milliliter, the general guideline is that, for intracervical insemination (ICI), straws or vials making a total of 20 million motile spermatozoa in total is recommended. This is equal to 8 straws or vials 0.5 ml with MOT5, or 2 straws or vials of MOT20. For intrauterine insemination (IUI), 1–2 MOT5 straws or vials is regarded sufficient. In WHO terms, it is thus recommended to use approximately 20 million grade a+b sperm in ICI, and 2 million grade a+b in IUI.

Here, too, there is no single rule. In some species (for example, in hydroids like Campanularia or tunicate like Ciona), the swimming direction of the spermatozoa changes abruptly towards the chemoattractant source. In others (for example, in sea urchin, hydromedusa, fern, or fish such as Japanese bitterlings), the approach to the chemoattractant source is indirect and the movement is by repetitive loops of small radii. In some species (for example, herring or the ascidian Ciona) activation of motility precedes chemotaxis.Kaupp, U.B., Hildebrand, E. and Weyand, I. (2006) Sperm chemotaxis in marine invertebrates - molecules and mechanism.

In sperm chemotaxis, the oocyte secretes a chemoattractant, which, as it diffuses away, forms a concentration gradient: a high concentration close to the egg, and a gradually lower concentration as the distance from the oocyte increases. Spermatozoa can sense this chemoattractant and orient their swimming direction up the concentration gradient towards the oocyte. Sperm chemotaxis was demonstrated in a large number of non-mammalian species, from marine invertebrates to frogs.Al-Anzi, B. and Chandler, D.E. (1998) A sperm chemoattractant is released from Xenopus egg jelly during spawning. Dev. Biol.

Here, too, there is no single rule. In some species (for example, in hydroids like Campanularia or tunicate like Ciona), the swimming direction of the spermatozoa changes abruptly towards the chemoattractant source. In others (for example, in sea urchin, hydromedusa, fern, or fish such as Japanese bitterlings), the approach to the chemoattractant source is indirect and the movement is by repetitive loops of small radii. In some species (for example, herring or the ascidian Ciona) activation of motility precedes chemotaxis.Kaupp, U.B., Hildebrand, E. and Weyand, I. (2006) Sperm chemotaxis in marine invertebrates - molecules and mechanism.

Drawings of spermatozoa from a paper authored by Justine Justine has worked on several fields during his career. His early research and his theses were about sperm ultrastructure in parasitic flatworms and its use for phylogeny. He then worked on systematics of nematodes, monogeneans and other parasites, especially the species from coral reef fish. Justine has published more than 250 papers since 1981 and described more than one hundred new species, which are all parasitic animals belonging mainly to the Nematoda and Monogenea, and also Digenea, Cestoda, and Crustacea.

Zika can be transmitted from men and women to their sexual partners; most known cases involve transmission from symptomatic men to women. As of April 2016, sexual transmission of Zika has been documented in six countries – Argentina, Australia, France, Italy, New Zealand, and the United States – during the 2015 outbreak. ZIKV can persist in semen for several months, with viral RNA detected up to one year. The virus replicates in the human testis, where it infects several cell types including testicular macrophages, peritubular cells and germ cells, the spermatozoa precursors.

The prostatic fluid is expelled in the first part of ejaculate, together with most of the sperm, because of the action of smooth muscle tissue within the prostate. In comparison with the few spermatozoa expelled together with mainly seminal vesicular fluid, those in prostatic fluid have better motility, longer survival, and better protection of genetic material. Disorders of the prostate include enlargement, inflammation, infection, and cancer. The word prostate comes from Ancient Greek προστάτης, prostátēs, meaning "one who stands before", "protector", "guardian", with the term originally used to describe the seminal vesicles.

Eleven months after Brandley was convicted and sentenced to death, his appellate lawyers discovered that exculpatory evidence had disappeared while in the custody of the prosecution, including a Caucasian pubic hair and other hairs recovered from Fergeson's body that were neither hers nor Brandley's.Haines 88. Also missing were photographs taken of Brandley on the day of the crime showing that he was not wearing the belt that the prosecution claimed had been the murder weapon. The missing evidence was all the more troubling in light of the pretrial destruction of the spermatozoa.

The presence of anti-sperm antibodies in infertile men was first reported in 1954 by Rumke and Wilson. It has been noticed that the number of cases of sperm autoimmunity is higher in the infertile population leading to the idea that autoimmunity could be a cause of infertility. Anti sperm antigen has been described as three immunoglobulin isotopes (IgG, IgA, IgM) each of which targets different part of the spermatozoa. If more than 10% of the sperm are bound to anti-sperm antibodies (ASA), then infertility is suspected.

The best prominent example of a motor protein is the muscle protein myosin which "motors" the contraction of muscle fibers in animals. Motor proteins are the driving force behind most active transport of proteins and vesicles in the cytoplasm. Kinesins and cytoplasmic dyneins play essential roles in intracellular transport such as axonal transport and in the formation of the spindle apparatus and the separation of the chromosomes during mitosis and meiosis. Axonemal dynein, found in cilia and flagella, is crucial to cell motility, for example in spermatozoa, and fluid transport, for example in trachea.

1995 saw the release of Sueño Stereo, the last of Soda's 7 studio albums. The cover depicts three speaker cones (meant to symbolize egg cells) ready to be "fertilized" by black spermatozoa, the latter of which resembles earbuds. This motif is symbolic of the album's concept, and is even used as a focal point in the music video for "Ella usó mi cabeza como un revólver", a single from the recording. After a three-year absence, on 29 June 1995, Soda released Sueño Stereo, their 7th and final studio album.

The tubules are lined with a layer of cells (germ cells) that from puberty into old age, develop into sperm cells (also known as spermatozoa or male gametes). The developing sperm travel through the seminiferous tubules to the rete testis located in the mediastinum testis, to the efferent ducts, and then to the epididymis where newly created sperm cells mature (see spermatogenesis). The sperm move into the vas deferens, and are eventually expelled through the urethra and out of the urethral orifice through muscular contractions. However, most fish do not possess seminiferous tubules.

SICM was used to image a living neural cell from rat brain, determine the life cycle of microvilli, observe the movement of protein complexes in spermatozoa. SICM has been combined with fluorescence microscopy and förster resonance energy transfer. SICM has been used in a "smart patch-clamp" technique, clamping the pipette by suction to the surface of a cell and then monitoring the activity of the sodium channels in the cell membrane. A combination of AFM and SICM was able to obtain high resolution images of synthetic membranes in ionic solutions.

Expression of DAZ proteins varies between species but is mainly expressed in Primordial Germ Cells (PGCs). One DAZ homologue is expressed in nearly every stage of spermatogenesis, from PGCs to mature spermatozoa. The conservation of DAZ family genes among various species ranging from unicellular organisms to humans indicates their important role in fertility. More precisely, DAZ is only present in higher primates, without any homologues being present in unicellular organisms whereas BOULE is found in species ranging from sea anemones to humans and DAZL is conserved among vertebrates.

Richard Hertwig in 1930 Richard Wilhelm Karl Theodor Ritter von Hertwig (23 September 1850 in Friedberg, Hesse – 3 October 1937 in Schlederloh, Bavaria), also Richard Hertwig or Richard von Hertwig, was a German zoologist and professor of 50 years, notable as the first to describe zygote formation as the fusing of spermatozoa inside the membrane of an egg cell during fertilization. "Richard von Hertwig – Wikipedia" (German), German Wikipedia, 2006-10-29, de.wikipedia.org webpage: GermanWP-Richard_von_Hertwig. Richard Hertwig was the younger brother of Oscar Hertwig, who also analyzed zygote formation.

The females can store sperm indefinitely. For primitive insects, the male deposits spermatozoa on the substrate, sometimes stored within a special structure; courtship involves inducing the female to take up the sperm package into her genital opening, but there is no actual copulation. In groups that have reproduction similar to spiders, such as dragonflies, males extrude sperm into secondary copulatory structures removed from their genital opening, which are then used to inseminate the female. In dragonflies, it is a set of modified sternites on the second abdominal segment.

Male superb fairywren in breeding plumage Post-copulatory sexual selection is one of the main factors that drives the evolution of sperm morphology and ultimately its relative ability to fertilize an egg after copulation has occurred. Sperm competition occurs when a female is inseminated by multiple males during one breeding season resulting in differential fertilization success among males. In birds, the last male to inseminate the female usually fertilizes the highest proportion of eggs because by the time fertilization occurs, the oldest spermatozoa have been lost. This is known as last male sperm precedence.

Antibiotics are almost universal in semen extenders, especially those being used for shipping or freezing semen. Ticarcillin (often used in combination with clavulanic acid under the designation timentin), amikacin sulfate, penicillin, and gentamicin are commonly used. The latter - gentamicin - has been noted to reduce sperm motility in the equine.Aurich C., Spergser J., (2007) Influence of bacteria and gentamicin on cooled-stored stallion spermatozoa; Theriogenology 67:5; 912-918 In human semen extenders, antibiotics are required for regulatory reasons, so their use is almost universal in clinics, even though antibiotics can be detrimental to sperm.

Sperm sorting is a means of choosing what type of sperm cell is to fertilize the egg cell. Several conventional techniques of centrifugation or swim-up. Newly applied methods such as flow cytometry expand the possibilities of sperm sorting and new techniques of sperm sorting are being developed. It can be used to sort out sperm that are most healthy, as well as for determination of more specific traits, such as sex selection in which spermatozoa are separated into X- (female) and Y- (male) chromosome bearing populations based on their difference in DNA content.

A diagram showing a copper IUD in place in uterus. The copper IUD's primary mechanism of action is to prevent fertilization. p. S28: > Conclusions > Active substances released from the IUD or IUS, together with products > derived from the inflammatory reaction present in the luminal fluids of the > genital tract, are toxic for spermatozoa and oocytes, preventing the > encounter of healthy gametes and the formation of viable embryos. The > current data do not indicate that embryos are formed in IUD users at a rate > comparable to that of nonusers.

A semen analysis typically measures the number of sperm per millilitre of ejaculate, and analyzes the morphology (shape) and motility (ability to swim forward) of the sperm (the typical ejaculate of a healthy, physically mature young adult male of reproductive age with no fertility- related problems usually contains 300–500 million spermatozoa, though only a couple of hundred survive in the acidic environment of the vagina to be candidates for successful fertilization). Also usually measured are the concentration of white blood cells, the level of fructose in the semen, and the volume, pH, and liquefaction time of the ejaculate.

On the underside of the prothallus, the male reproductive organs are located, while the female ones are at the top. The male sex organs are called antheridia and the female ones are called archegonia. When the sperm and the egg has matured and there is enough moisture on the prothallus, the antheridia release the spermatozoa which is attracted by the scent coming from the ripened egg and swims towards it to fertilize it. Once fertilized, the cell can divide and the new baby fern starts to grow with help from the prothallus, which supports it with nutrients.

Posthumous sperm retrieval (PSR) is a procedure in which spermatozoa are extracted from a human male after he has been pronounced legally brain dead. There has been significant debate over the ethicality and legality of the procedure, and on the legal rights of the child and surviving parent if the gametes are used for impregnation.Orr, RD; Siegler, M (2002) Is posthumous semen retrieval ethically permissible? J Med Ethics 2002;28:299–302 Cases of post-mortem conception have occurred ever since human artificial insemination techniques were first developed, with sperm donated to a sperm bank being used following the death of the donor.

Two specimens of Pseudobiceros bedfordi about to engage in penis fencing Like all flatworms in the genus Pseudobiceros, they are hermaphroditic and have two penises. During mating, they fence with one another, using their penises, attempting to stab and inject sperm in their opponent, while avoiding being fertilized by their opponent. They are able to inseminate their opponent by injecting their sperm into any region of the other's body they are able to penetrate. After successfully injecting the other, the spermatozoa stream through their partner's body on their way to ovaries, where they will fertilize the eggs.

The DNA lysate is further purified and used to generate an autosomal STR profile of the victim. To further obtain the male DNA which will identify the perpetrator, harsher lysis conditions will be applied afterwards to the very same filter column without the necessity of sample carriage in order to break open the retained spermatozoa. Due to the high yield of DNA, the chance of a successful DNA-profile by downstream analysis is significantly increased. This simple handling allows time savings and higher throughput in this manual process to improve crime solution rates and to speed up analysis of backlogged crime samples.

Sir Alan Sterling Parkes FRS CBE (10 September 1900 - 17 July 1990) was an English reproductive biologist credited with Christopher Polge and Audrey Smith for the discovery that spermatozoa can be protected against induced damage induced by freezing and low-temperature storage using glycerol. This work enabled the development of the field of cryobiology. Additionally, he published on the reproductive effects of X-rays on mice, hormonal control of secondary sexual characteristics in birds, and aided Hilda Bruce in research that established the Bruce effect. In 1962, Parkes was awarded the Cameron Prize for Therapeutics of the University of Edinburgh.

Viability can be distinguished from the all-or- nothing states of life and death by the use of a quantifiable index that ranges between the integers of 0 and 1 or, if more easily understood, the range of 0% and 100%. Viability can be observed through the physical properties of cells, tissues, and organs. Some of these include mechanical activity, motility, such as with spermatozoa and granulocytes, the contraction of muscle tissue or cells, mitotic activity in cellular functions, and more. Viability assays provide a more precise basis for measurement of an organism's level of vitality.

Introduced by Robert Hooke to the Royal Society on 3 July 1679 to show experiments on spermatozoa, then recently discovered by Leeuwenhoek, Slare was recommended for election by Haak. He was admitted Fellow on 16 December 1680, and became a member of the council on 30 November 1682. From early 1683 he and Edward Tyson acted as Curators of Experiments for the society, and Slare was very active in this role for about 18 months.Boas Hall, p. 27. Slare graduated M.D. at the University of Utrecht in 1679; and was admitted M.D. at Oxford on 9 September 1680.

After fusion with the oocyte, PLC ζ of the spermatozoa is released into the oocyte leading to an increase in Ca2+ levels that will activate CaMKII which will degrade MPF, leading to the resumption of meiosis. The increased Ca2+ levels will induce the exocytosis of cortical granules that degrade ZP receptors, used by sperm to penetrate the oocyte, blocking polyspermy. Deregulation of these pathways will lead to several diseases like, oocyte maturation failure syndrome which results in infertility. Increasing our molecular knowledge of oocyte development mechanisms could improve the outcome of assisted reproduction procedures, facilitating conception.

In case of failure with PVS, spermatozoa are sometimes collected by electroejaculation: an electrical probe is inserted into the rectum, where it triggers ejaculation. The success rate is 80–100%, but the technique requires anaesthesia and does not have the potential to be done at home that PVS has. Both PVS and electroejaculation carry a risk of autonomic dysreflexia, so drugs to prevent the condition can be given in advance and blood pressure is monitored throughout the procedures for those who are susceptible. Massage of the prostate gland and seminal vesicles is another method to retrieve stored sperm.

Brian Dale Brian Dale (31 August 1951) is a British reproductive scientist living in Sorrento, Italy. He is currently owner and Director of the Centre for Assisted Fertilization, which has offices in Naples and Rome and Director of London Fertility Associates Ltd in London. He is also founder and partner in the Swiss-based company, International Fertility Associates. While working for the Stazione Zoologica, Naples, and on leave at the National Institutes of Health in Bethesda in 1983, he was attributed with the discovery of a soluble sperm factor in spermatozoa that is responsible for the activation of oocytes.

Intracellular calcium influx contributes to sperm capacitation and hyperactivation, causing a more violent and rapid non-linear motility pattern as sperm approach the oocyte. The capacitated spermatozoon and the oocyte meet and interact in the ampulla of the fallopian tube. Rheotaxis, thermotaxis and chemotaxis are known mechanisms that guide sperm towards the egg during the final stage of sperm migration. Spermatozoa respond (see Sperm thermotaxis) to the temperature gradient of ~2 °C between the oviduct and the ampulla, and chemotactic gradients of progesterone have been confirmed as the signal emanating from the cumulus oophorus cells surrounding rabbit and human oocytes.

They are expressed in highest concentration in the nervous system, although they also express in other body systems such as the reproductive organs, including both eggs and spermatozoa. Synapsin function also increases as the organism matures, reaching its pique at sexual maturity. Current studies suggest the following hypothesis for the role of synapsin: synapsins bind synaptic vesicles to components of the cytoskeleton which prevents them from migrating to the presynaptic membrane and releasing neurotransmitter. During an action potential, synapsins are phosphorylated by PKA (cAMP dependent protein kinase), releasing the synaptic vesicles and allowing them to move to the membrane and release their neurotransmitter.

The spermatozoa move to the spermatheca in the roof of the cloaca where they remain until ovulation which may be many months later. Courtship rituals and methods of transfer of the spermatophore vary between species. In some, the spermatophore may be placed directly into the female cloaca while in others, the female may be guided to the spermatophore or restrained with an embrace called amplexus. Certain primitive salamanders in the families Sirenidae, Hynobiidae and Cryptobranchidae practice external fertilisation in a similar manner to frogs, with the female laying the eggs in water and the male releasing sperm onto the egg mass.

Transgenic animals have been produced successfully using gene transfer techniques such as sperm-mediated gene transfer. Though this production has been successful, the efficiency of the process is low. Low efficiency of SMGT in the production of transgenic animals is mainly due to poor uptake of the exogenous DNA by the sperm cells, thus reducing the number of fertilized oocytes with transfected spermatozoa.5 From 1989 to 2004, there were over 30 claims for the production of viable transgenic animals using SMGT, but only about 25 percent of these demonstrated a transmission of the transgenes beyond the F0 generation.

The DAZ (Deleted in AZoospermia) gene family encodes potential RNA binding proteins that are expressed in prenatal and postnatal germ cells of males and females. The protein encoded by this gene is localized to the nucleus and cytoplasm of fetal germ cells and to the cytoplasm of developing oocytes. In the testis, this protein is localized to the nucleus of spermatogonia but relocates to the cytoplasm during meiosis where it persists in spermatids and spermatozoa. Transposition and amplification of this autosomal gene during primate evolution gave rise to the DAZ gene cluster on the Y chromosome.

Aequorea victoria juvenile medusae are asexually budded off hydroid colonies in late spring; these free-living hydromedusae will spend all of their lives in the plankton. The medusa spends its first stage of life growing quickly, and after reaching approximately 3 cm will begin producing gametes for reproduction. Each medusa is either a male or a female. The eggs and spermatozoa mature daily in the medusa gonads, given enough food, and are free-spawned into the water column in response to a daily light cue, where they are fertilized and eventually settle out to form a new hydroid colony.

The male typically deposits a spermatophore on the ground or in the water according to species, and the female picks this up with her vent. The spermatophore has a packet of sperm supported on a conical gelatinous base, and often an elaborate courtship behavior is involved in its deposition and collection. Once inside the cloaca, the spermatozoa move to the spermatheca, one or more chambers in the roof of the cloaca, where they are stored for sometimes lengthy periods until the eggs are laid. In the most primitive salamanders, such as the Asiatic salamanders and the giant salamanders, external fertilization occurs, instead.

SCNN1A, SCNN1B, and SCNN1G are commonly expressed in tight epithelia that have low water permeability. The major organs where ENaC is expressed include parts of the kidney tubular epithelia, the respiratory airway, the female reproductive tract, testis, including, spermatogonia in the seminiferous tubules, Sertoli cells, and spermatozoa, colon and salivary glands. In the skin, SCNN1A is expressed in the keratinocytes in the epidermal layer, in the sebaceous sweat glands, and the smooth muscle cells mostly within the cytoplasm. In contrast, in the eccrine sweat glands ENaC is mostly located on the luminal surface of eccrine duct epithelia.

Females exercise mate choice before, during, and after mating and can distinguish between males who were reared on high-quality versus low-quality host plants. The ability to recognize adults reared on higher quality host plants is selected for because males fed better plants during development provide superior nuptial gifts. In comma butterflies, nuptial gifts are edible spermatophores containing spermatozoa and nutrients. When comparing the two common host plants U. dioica and S. caprea, females preferentially choose to mate with males reared on U. dioica, because these males have higher protein content and increased spermatophore production.

The use of love darts by the land snail Monachoides vicinus is a form of sexual selection Two Helicid snails make contact prior to mating. Two Helix pomatia snails mating The great majority of land snails are hermaphrodites with a full set of reproductive organs of both sexes, able to produce both spermatozoa and ova. A few groups of land snails such as the Pomatiidae, which are distantly related to periwinkles, have separate sexes: male and female. The age of sexual maturity varies depending on species of snail, ranging from as little as 6 weeks to 5 years.

Using single-lensed microscopes of his own design, van Leeuwenhoek was the first to experiment with microbes, which he originally referred to as dierkens, diertgens or diertjes (Dutch for "small animals" [translated into English as animalcules, from Latin animalculum = "tiny animal"]). Through his experiments, he was the first to relatively determine their size. Most of the "animalcules" are now referred to as unicellular organisms, although he observed multicellular organisms in pond water. He was also the first to document microscopic observations of muscle fibers, bacteria, spermatozoa, red blood cells, crystals in gouty tophi, and blood flow in capillaries.

Sexes are separate. Like other annelids, the coelom stores and provides nutrients for gametes.. When they reproduce, they simply shed their gametes straight into the water where the ova and spermatozoa become part of the zooplankton and are carried by the currents to new sites, where the juvenile worms settle into the substrate. Length of the planktonic stage is unknown but comparison with other serpulids suggests it may be between six days and two months, although in other species the period has been shown to vary with season, salinity or food availability, and delayed settling may cause reduced discrimination of substrata during settling (see ten Hove, 1979 for additional references).

The acrosome itself is divided into two functional domains, the inner acrosomal membrane which faces the nucleus and the outer acrosomal membrane which is in contact with the exterior surfaces of the sperm. This compartmentalisation of functions is vital to the fusion of the sperm with the egg as, it is the outer acrosomal domain which initiates the acrosome reaction, enabling the sperm to fuse. Vezatin is present in both these domains, but the translocation of vezatin from the inner to the outer membrane is unknown. Furthermore, vezatin is not expressed in the epididymal cells, thus vezatin cannot be added to the exterior membrane during maturation of the spermatozoa.

Differential extraction (also known as differential lysis) refers to the process by which the DNA from two different types of cells can be extracted without mixing their contents. The most common application of this method is the extraction of DNA from vaginal epithelial cells and sperm cells from sexual assault cases in order to determine the DNA profiles of the victim and the perpetrator. Its success is based on the fact that sperm cells pack their DNA using protamines (rather than histones) which are held together by disulfide bonds. The protamines sequester DNA from spermatozoa, making it more resilient to DNA extraction than DNA from epithelial cells.

Spermatophores of a mole salamander A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores may additionally contain nourishment for the female, in which case it is called a nuptial gift, as in the instance of bush crickets. In the case of the toxic moth Utetheisa ornatrix, the spermatophore includes sperm, nutrients, and pyrrolizidine alkaloids which prevent predation because it is poisonous to most organisms. However, in some species such as the Edith's checkerspot butterfly, the "gift" provides little nutrient value.

Reproductive isolation between species appears, in certain cases, a long time after fertilization and the formation of the zygote, as happens – for example – in the twin species Drosophila pavani and D. gaucha. The hybrids between both species are not sterile, in the sense that they produce viable gametes, ovules and spermatozoa. However, they cannot produce offspring as the sperm of the hybrid male do not survive in the semen receptors of the females, be they hybrids or from the parent lines. In the same way, the sperm of the males of the two parent species do not survive in the reproductive tract of the hybrid female.

It has been suggested that the pre-ejaculate ("Cowper's fluid") emitted by the penis prior to ejaculation may contain spermatozoa (sperm cells), which would compromise the effectiveness of the method. However, several small studies have failed to find any viable sperm in the fluid. While no large conclusive studies have been done, it is believed by some that the cause of method (correct-use) failure is the pre- ejaculate fluid picking up sperm from a previous ejaculation. For this reason, it is recommended that the male partner urinate between ejaculations, to clear the urethra of sperm, and wash any ejaculate from objects that might come near the woman's vulva (e.g.

Difference of beating pattern of flagellum and cilium The regular beat patterns of eukaryotic cilia and flagella generate motion on a cellular level. Examples range from the propulsion of single cells such as the swimming of spermatozoa to the transport of fluid along a stationary layer of cells such as in the respiratory tract. Though eukaryotic flagella and motile cilia are ultrastructurally identical, the beating pattern of the two organelles can be different. In the case of flagella, the motion is often planar and wave-like, whereas the motile cilia often perform a more complicated three-dimensional motion with a power and recovery stroke.

Diagram of a human sperm cell Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, "female" reproductive cell and a smaller, "male" one). Animals produce motile sperm with a tail known as a flagellum, which are known as spermatozoa, while some red algae and fungi produce non-motile sperm cells, known as spermatia. Flowering plants contain non-motile sperm inside pollen, while some more basal plants like ferns and some gymnosperms have motile sperm. Sperm cells form during the process known as spermatogenesis, which in amniotes (reptiles and mammals) takes place in the seminiferous tubules of the testes.

Different methods used for semen collection are masturbation, condom collection and epididymal extraction, etc. The sample should never be obtained through coitus interruptus for several reasons: Some part of ejaculation could be lost, bacterial contamination could happen and the acid vaginal pH could be detrimental for sperm motility. The optimal sexual abstinence for semen sample obtaining is from 2–7 days. The most common way to obtain a semen sample is through masturbation and the best place to obtain it is in the clinic where the analysis will take place in order to avoid temperature changes during the transport that can be lethal for some spermatozoa.

The physiological role of this enzyme is not yet found and thus it is still a mystery why the seminal fluid in bovine has such a higher concentration of this enzyme. In the evolutionary process, it has acquired new behaviors such as being a dimer with composite active sites binding firmly to anionic glycolipids, including bovine spermatozoa seminolipid, a fusogenic sulfated galactolipid possessing immunosuppressive and cytostatic activities whereas the ancestral RNase does not possess these behaviors. The homolog of RNase A, bovine seminal ribonuclease (BS-RNase), has a specific antitumor activity. In the immunoregulation of both male and female genital systems, the seminal plasma plays a prominent role in immunosuppression.

The female's eggs are fertilized in the mantle cavity (brooding chamber) when spermatozoa are filtered into her gill slits from the surrounding water. The fertilized eggs will then move into the branchial chamber (mantle cavity). The fertilized eggs will develop into veliger larvae and will stay in the females mantle cavity for 10–12 days for further development. On the first day the larvae develop into a blastulae (mass of cells with a center cavity), on day two they develop into a gastrulae (hollow two layered sac), on the third day they develop into trochophore (free-swimming, conciliated larvae), on the fourth day the valves on the dorsal surface become defined.

He spent the first year in Chicago, the second at the Marine Biological Laboratory in Woods Hole and finishing by studying Anatomy and Embryology in 1927–1928 at University College Hospital Medical School, under Grafton Elliot Smith. His scientific activity, after his work on the dura mater, focused on three areas: the hypothalamic–pituitary–adrenal axis, the reform of medical education at the university level,Petrovanu, p.21 and the physiology of spontaneous movement (motility) in spermatozoa. Grigore T. Popa, "Sur la motilité des spermatozoïdes chez quelques vertébrés supérieurs (taureau, bélier, homme)", in Comptes rendus hebdomadaires des séances de la Société de biologie et de ses filiales, Vol.

B. balanus is a cross-fertilising hermaphrodite and the single brood of nauplii is produced in the middle of winter. In mature individuals (barnacles at least ten millimetres in diameter) the white vesiculae seminales are very much enlarged at this time and filled with spermatozoa, occupying much of the body cavity and the penis is also greatly enlarged. At the same time, a creamy mass of eggs are present in the ovarian tubules. Fertilisation takes place over the course of a few days in each group of barnacles and the fertilised eggs change to an orange colour and then to a greyish-brown as the nauplii develop.

The Strobo Trip toy combines a pulsating strobe light and 24 disks designed by David Bizzaro, Michelle Martin-Coyne, George Salisbury, Daniel Huffman and Dylan Bradaway. The toy creates a stroboscopic effect (similar to a Phenakistoscope) when components are rotating. Most of the discs have geometric psychedelic illustrations, but one of them has drawings of spermatozoa fertilizing ova. The first track, "Butterfly, How Long It Takes to Die" appeared with a different mix in the 2013 Flaming Lips album The Terror. "I Found a Star on the Ground" is a 6-hour long song recorded over a period of 3 weeks from August 23 to September 17, 2011.

Voltage-gated hydrogen channel 1 is a protein that in humans is encoded by the HVCN1 gene. Voltage-gated hydrogen channel 1 is a voltage-gated proton channel that has been shown to allow proton transport into phagosomes and out of many types of cells including spermatozoa, electrically excitable cells and respiratory epithelial cells. The proton-conducting HVCN1 channel has only transmembrane domains corresponding to the S1-S4 voltage sensing domains (VSD) of voltage-gated potassium channels and voltage-gated sodium channels. Molecular simulation is consistent with a water-filled pore that can function as a "water wire" for allowing hydrogen bonded H+ to cross the membrane.

Following the 1984 Parpalaix case in France, in which the widow of deceased cancer patient Alain Parpalaix obtained permission from the courts to be inseminated with her husband's spermatozoa after his death, the Centre d’Etude et de Conservation du Sperme Humain (Center for the Study and Preservation of Human Sperm) petitioned the courts successfully for a full ban on posthumous insemination,Bahadur, G (2002) "Death and conception", Human Reproduction Oct 2002;17(10):2769–2775 in line with the country's ban on in vitro fertilisation for post-menopausal women."62-year-old woman gives birth" , CNN, May 30, 2001. Retrieved June 28, 2007. Similar legislation exists in Germany, Sweden, and the Australian states of Victoria, Western Australia and Taiwan.

Pregnancy testing was conducted in the mid-20th century by injecting urine from a woman into a male toad's lymph sacs, and if spermatozoa appeared in the toad's urine, the patient was deemed to be pregnant. The tests using toads were faster than those employing mammals; the toads were easier to raise, and, although the initial 1948 discovery employed Bufo arenarum for the tests, it soon became clear that a variety of anuran species were suitable, including the cane toad. As a result, toads were employed in this task for around 20 years. As a laboratory animal, the cane toad is regarded as ideal; they are plentiful, and easy and inexpensive to maintain and handle.

Spermatogenesis produces mature male gametes, commonly called sperm but more specifically known as spermatozoa, which are able to fertilize the counterpart female gamete, the oocyte, during conception to produce a single-celled individual known as a zygote. This is the cornerstone of sexual reproduction and involves the two gametes both contributing half the normal set of chromosomes (haploid) to result in a chromosomally normal (diploid) zygote. To preserve the number of chromosomes in the offspring – which differs between species – one of each gamete must have half the usual number of chromosomes present in other body cells. Otherwise, the offspring will have twice the normal number of chromosomes, and serious abnormalities may result.

The initial segment of the epididymis, first described in the guinea pig epididymis, is a histologically distinct region of tall pseudostratified columnar epithelium that receives spermatozoa from the ductuli efferentes (Figure 1). The epididymis is the primary sperm storage organ in male reptiles. In all reptiles and mammals the sperm storage region of the epididymis can objectively be identified as that distal extremity of the epididymis that exhibits a widened diameter of duct which contains additional layers of circumferential smooth muscle capable of contraction during ejaculation in direct continuity with the vas deferens (Figure 1). This sperm storage region has been described as the anatomical cauda epididymis or the histologic terminal segment of the epididymis.

Justine has been the Editor-in- chief of the Mémoires du Muséum National d’Histoire Naturelle, from 1992 to 1998, and of Zoosystema, a journal of zoology, from 1998 to 2002; both are journals published by the National Museum of Natural History in Paris. Since 2013, he is the Editor-in-chief of the open-access journal Parasite, the official journal of the French Society of Parasitology. Justine is a member of the Editorial Board of the parasitological journals Helminthologia, Acta Parasitologica, and Folia Parasitologica, and is one of the numerous Academic Editors of the megajournal PeerJ. Justine has also been the Editor of a few books, on spermatozoa,Jamieson, Barrie G. M., Justine, Jean-Lou, & Ausió, Juan (Eds)(1995).

These special cells, called teratocytes, grow to become giant cells visible to the naked eye. The teratocytes secrete hormones which work in tandem with the virus and the wasp venom to arrest the development of the host. Following hatching in the caterpillar, the wasp larvae will undergo 2 molts inside the host caterpillar’s hemocoel and, after 12 to 16 days post oviposition, the 3rd instar wasp larvae will emerge from the caterpillar and spin cocoons from which the adult wasps fly about 4 to 8 days later. This insect has the shortest flagellated spermatozoa in animals, being 6.6 µm long (nucleus and flagellum), 8800 times shorter than the longest ones (Drosophila bifurca).

Kode Technology has been used for the in vitro modification of murine embryos, spermatozoa, zebra fish, epithelial/endometrial cells and red blood cells to create cellular quality controls systems, serologic kits (teaching), rare antigen expression, add infectious markers onto cells, modified cell adhesion/interaction/separation/immobilisation, and labelling. It has also been intravascularly infused for in vivo modification of blood cells and neutralisation of circulating antibodies and in in vivo imaging of circulating bone marrow kodecytes in zebrafish. Kode FSL constructs have also been applied to non-biological surfaces such as modified cellulose, paper, silica, polymers, natural fibers, glass and metals and has been shown to be ultra-fast in labelling these surfaces.

The scallop family is unusual in that some members of the family are dioecious (males and females are separate), while other are simultaneous hermaphrodites (both sexes in the same individual), and a few are protoandrous hermaphrodites (males when young then switching to female). Red roe is that of a female, and white, that of a male. Spermatozoa and ova are released freely into the water during mating season, and fertilized ova sink to the bottom. After several weeks, the immature scallops hatch and the larvae, miniature transparent versions of the adults called "spat", drift in the plankton until settling to the bottom again (an event called spatfall) to grow, usually attaching by means of byssal threads.

The redundancy principle in biology expresses the need of many copies of the same entity (cells, molecules, ions) to fullfill a biological function. Examples are numerous: disproportionate numbers of spermatozoa during fertilization compared to one egg, large number of neurotransmitters released during neuronal communication compared to the number of receptors, large numbers of released calcium ions during transient in cells and many more in molecular and cellular transduction or gene activation and cell signaling. This redundancy is particularly relevant when the sites of activation is physically separated from the initial position of the molecular messengers. The redundancy is often generated for the purpose of resolving the time constraint of fast-activating pathways.

"Bladderball: 30 years of zany antics, dangerous fun ", Eli Muller, Yale Daily News, February 28, 2001 "Magically released from the Fallopian tube-like tunnel of Phelps Gateway, it bounces rhythmically above the swarming hands of the crowd like a huge ripe ovum being battered by thousands of frantic spermatozoa. The accumulated libidinal energy aroused by the pre-game skirmishes (but largely repressed, because of homophobic anxiety) is immediately transferred onto the permitted female form of the bladderball. "In symbolic transaction occurring during each game is this: each team strives to 'fertilize' the egg and thus become the sole possessor of its life-giving power. In this respect the game fits well with the competitive nature of Yale society.

Creatine kinase (CK), also known as creatine phosphokinase (CPK) or phosphocreatine kinase, is an enzyme () expressed by various tissues and cell types. CK catalyses the conversion of creatine and uses adenosine triphosphate (ATP) to create phosphocreatine (PCr) and adenosine diphosphate (ADP). This CK enzyme reaction is reversible and thus ATP can be generated from PCr and ADP. In tissues and cells that consume ATP rapidly, especially skeletal muscle, but also brain, photoreceptor cells of the retina, hair cells of the inner ear, spermatozoa and smooth muscle, PCr serves as an energy reservoir for the rapid buffering and regeneration of ATP in situ, as well as for intracellular energy transport by the PCr shuttle or circuit.

In contrast, if both vasa deferentia are obstructed (which may be the result of intended sterilization), a semen analysis will also reveal aspermia/azoospermia, but an almost normal volume of the semen, since the efflux of the seminal vesicles is not hindered. This is because approx. 80% of the volume of the semen is the gel-like fluid originating from the seminal vesicles whereas the fraction from the testicles / epididymis, which contains the spermatozoa accounts for only 5–10% of the volume of the semen. In addition, if an obstruction of the vasa deferentia is the cause for the azoospermia, the concentration of fructose in the semen will also be normal, since the fructose comes primarily from the fluid stored in the seminal vesicles.

Heilmann's comparative illustrations of the embryos and adults of several extant birds and reptiles In this section, Heilmann draws evidence from his observations of germ cells, impregnation, cell division, ontogeny and comparative embryology about the probable ancestry of birds. A fair amount of detail is devoted early in the section to comparative studies between the germ cells of many different species of extant bird and reptile (and several mammals), including some comments on the corkscrew locomotion observed in the spermatozoa cells of several bird and reptile species, but no mammals.Heilmann (1926) pp. 61–63. He then goes on to offer a similar comparison between the egg cells of birds and reptiles, and finds considerably more similarity there than either has to the egg cell of a mammal.

The existence of two sexes seems to have been selected independently across different evolutionary lineages (see convergent evolution). The repeated pattern is sexual reproduction in isogamous species with two or more mating types with gametes of identical form and behavior (but different at the molecular level) to anisogamous species with gametes of male and female types to oogamous species in which the female gamete is very much larger than the male and has no ability to move. There is a good argument that this pattern was driven by the physical constraints on the mechanisms by which two gametes get together as required for sexual reproduction.. Accordingly, sex is defined across species by the type of gametes produced (i.e.: spermatozoa vs.

The abdominal terminus of male scorpionflies is enlarged into a "genital bulb", as seen in Panorpa communis The organs concerned specifically with mating and the deposition of eggs are known collectively as the external genitalia, although they may be largely internal. The components of the external genitalia of insects are very diverse in form and often have considerable taxonomic value, particularly among species that appear structurally similar in other respects. The male external genitalia have been used widely to aid in distinguishing species, whereas the female external genitalia may be simpler and less varied. The terminalia of adult female insects include internal structures for receiving the male copulatory organ and his spermatozoa and external structures used for oviposition (egg-laying; section 5.8).

Together with cohesion linkage between sister chromatids, CO recombination may help ensure the orderly segregation of the paired homologous chromosomes to opposite poles. In support of this, a study of aneuploidy in single spermatozoa by whole genome sequencing found that, on average, human sperm cells with aneuploid autosomes exhibit significantly fewer crossovers than normal cells. After the first chromosome segregation in meiosis I is complete, there is further chromosome segregation during the second equational division of meiosis II. Both proper initial segregation of chromosomes in prophase I and the next chromosome segregation during equational division in meiosis II are required to generate gametes with the correct number of chromosomes. CO recombinants are produced by a process involving the formation and resolution of Holliday junction intermediates.

Peritubular myoid cells play a crucial role in the self-renewal and maintenance of the spermatogonial stem cell (SSC) population. For those SSCs destined to form differentiating progenitor A1 spermatogonia (and hence spermatozoa), this is initiated at a defined stage during the spermatogenic cycle. The precise location of SSCs throughout various staged cohorts of the seminiferous tubule determines their renewal function, to continuously produce progeny. During stages II and IV of spermatogenesis, GDNF is secreted by peritubular myoid cells upon testosterone binding the androgen receptor (in contrast to GDNF secretion by the Sertoli cells during stages IX and I). Following this, GDNF binds GFRA1 on spermatogonial stem cells, and RET co-receptor (a transmembrane tyrosine kinase) is consequently signalled throughout all undifferentiated spermatogonia.

This has triggered the development of highly automated live-cell fluorescence microscopy systems, which can be used to observe cells over time expressing one or more proteins tagged with fluorescent proteins. For example, GFP had been widely used in labelling the spermatozoa of various organisms for identification purposes as in Drosophila melanogaster, where expression of GFP can be used as a marker for a particular characteristic. GFP can also be expressed in different structures enabling morphological distinction. In such cases, the gene for the production of GFP is incorporated into the genome of the organism in the region of the DNA that codes for the target proteins and that is controlled by the same regulatory sequence; that is, the gene's regulatory sequence now controls the production of GFP, in addition to the tagged protein(s).

Proteus reveals to a reluctant Susan that the computer wants to conceive a child through her. Proteus takes some of Susan's cells and synthesizes spermatozoa, modifying its genetic code to make it uniquely the computer's, in order to impregnate her; she will give birth in less than a month, and through the child the computer will live in a form that humanity will have to accept. Although Susan is its prisoner and it can forcibly impregnate her, Proteus uses different forms of persuasion – threatening a young girl whom Susan is treating as a child psychologist; reminding Susan of her young daughter, now dead; displaying images of distant galaxies; using electrodes to access her amygdala – because the computer needs Susan to love the child she will bear. In the end, Susan finally gives in.

Harvey's De motu cordis in 1628 was the beginning of the end for Galenic theory, and alongside Santorio Santorio's studies of metabolism, it served as an influential model of quantitative approaches to physiology.Magner, A History of the Life Sciences, pp 103–113 In the early 17th century, the micro- world of biology was just beginning to open up. A few lensmakers and natural philosophers had been creating crude microscopes since the late 16th century, and Robert Hooke published the seminal Micrographia based on observations with his own compound microscope in 1665. But it was not until Antonie van Leeuwenhoek's dramatic improvements in lensmaking beginning in the 1670s—ultimately producing up to 200-fold magnification with a single lens—that scholars discovered spermatozoa, bacteria, infusoria and the sheer strangeness and diversity of microscopic life.

Male Odonata have complex genitalia, different from those found in other insects. These include grasping cerci for holding the female and a secondary set of copulatory organs on the abdomen in which the sperm are held after being produced by the primary genitals. To mate, the male grasps the female by the thorax or head and bends her abdomen so that her own genitalia can be grasped by the copulatory organs holding the sperm. Male odonates have a copulatory organ on the ventral side of abdominal segment 2 in which they store spermatozoa; they mate by holding the female's head (Anisoptera) or thorax (Zygoptera) with claspers located at the tip of the male abdomen; the female bends her abdomen forward to touch the male organ and receive sperm.

A somatic cell (from Ancient Greek σῶμα sôma, meaning "body"), or vegetal cell, is any biological cell forming the body of an organism; that is, in a multicellular organism, any cell other than a gamete, germ cell, gametocyte or undifferentiated stem cell. In contrast, gametes are cells that fuse during sexual reproduction, germ cells are cells that give rise to gametes, and stem cells are cells that can divide through mitosis and differentiate into diverse specialized cell types. For example, in mammals, somatic cells make up all the internal organs, skin, bones, blood and connective tissue, while mammalian germ cells give rise to spermatozoa and ova which fuse during fertilization to produce a cell called a zygote, which divides and differentiates into the cells of an embryo. There are approximately 220 types of somatic cell in the human body.

Apart from breaching of blood-testis barrier, epididymal distension, raised intraluminal pressure, and sperm granuloma formation leading spermatozoal phagocytosis seem to be contributing factors. As of 2017, it is unclear how or why women generally do not develop ASA, and why some women do develop them; the clearest correlations are that women whose male partners have ASA in their semen are more likely to have ASA, and women with ASA tend to react only to their partner's sperm and not to other men's sperm. The hypotheses for how women form ASA, as of 2017, includes cross-reactivity with microbial antigens, antibodies raised against ASA in their partner's semen, and a cytokine-driven immune response to ASA in their partner's semen. In women, spermatozoa in the genital tract after intercourse are not a factor in the production of antisperm antibodies.

3D cultures use sponge, models or scaffolds that resemble the elements of the extracellular matrix to achieve a more natural spatial structure of the seminiferous tubules and to better represent the tissues and the interaction between different cell types in an ex vivo experiment. Different components of the extracellular matrix such as collagen, agar and calcium alginate are commonly used to form the gel or scaffold which can provide oxygen and nutrients. To propagate 3D cultures, testicular cell cultures are imbedded into the porous sponge/scaffold and allowed to colonise the structure which can then survive for several weeks to allow spermatogonia to differentiate and mature into spermatozoa. In addition, shaking 3D cultures during the seeding process allows for an increased oxygen supply which helps overcome the issue of hypoxia and so improves the lifespan of cells.

Lazzaro Spallanzani (; 12 January 1729 – 11 February 1799) was an Italian Catholic priest (for which he was nicknamed Abbé Spallanzani), biologist and physiologist who made important contributions to the experimental study of bodily functions, animal reproduction, and animal echolocation. His research on biogenesis paved the way for the downfall of the theory of spontaneous generation, a prevailing idea at the time that organisms develop from inanimate matters, though the final death blow to the idea was dealt by French scientist Louis Pasteur a century later. His most important works were summed up in his book Experiencias Para Servir a La Historia de La Generación De Animales y Plantas (Experiences to Serve to the History of the Generation of Animals and Plants), published in 1786. Among his contributions were experimental demonstrations of fertilisation between ova and spermatozoa, and in vitro fertilisation.

The occluding junctions of Sertoli cells form the blood-testis barrier, a structure that partitions the interstitial blood compartment of the testis from the adluminal compartment of the seminiferous tubules. Because of the apical progression of the spermatogonia (sperm stem cells), the occluding junctions must be dynamically reformed and broken to allow the immunoidentical spermatogonia to cross through the blood-testis barrier so they can become immunologically unique. Sertoli cells control the entry and exit of nutrients, hormones and other chemicals into the tubules of the testis as well as make the adluminal compartment an immune-privileged site. The cell is also responsible for establishing and maintaining the spermatogonial stem cell niche, which ensures the renewal of stem cells and the differentiation of spermatogonia into mature germ that progress stepwise through the long process of spermatogenesis, ending in the release of spermatozoa in a process known as spermiation.

Noticing that sperm in a mixed sample tends to clump together-- making it less mobile--and to have a high mortality rate, reproductive biologist Robin Baker, formerly of the University of Manchester, proposed about a decade ago that some mammals, including humans, manufacture "killer" sperm whose only function is to attack foreign spermatozoa, destroying themselves in the process. To test this idea, reproductive biologist Harry Moore and evolutionary ecologist Tim Birkhead of the University of Sheffield in the U.K. mixed sperm samples from 15 men in various combinations and checked for how the cells moved, clumped together, or developed abnormal shapes. "These are very simple experiments, but we tried to mimic what goes on in the reproductive tract," Moore says. The team found no excess casualties from any particular donor or other evidence of warring sperm, they report in the 7 December Proceedings of the Royal Society.

Noticing that sperm in a mixed sample tends to clump together—making it less mobile—and to have a high mortality rate, reproductive biologist Robin Baker, formerly of the University of Manchester, proposed about a decade ago that some mammals, including humans, manufacture "killer" sperm whose only function is to attack foreign spermatozoa, destroying themselves in the process. To test this idea, reproductive biologist Harry Moore and evolutionary ecologist Tim Birkhead of the University of Sheffield in the U.K. mixed sperm samples from 15 men in various combinations and checked for how the cells moved, clumped together, or developed abnormal shapes. "These are very simple experiments, but we tried to mimic what goes on in the reproductive tract," Moore says. The team found no excess casualties from any particular donor or other evidence of warring sperm, they report in 7 December Proceedings of the Royal Society.

In the early 17th century, the micro-world of zoology was just beginning to open up. A few lensmakers and natural philosophers had been creating crude microscopes since the late 16th century, and Robert Hooke published the seminal Micrographia based on observations with his own compound microscope in 1665. But it was not until Antony van Leeuwenhoek's dramatic improvements in lensmaking beginning in the 1670s—ultimately producing up to 200-fold magnification with a single lens—that scholars discovered spermatozoa, bacteria, infusoria and the sheer strangeness and diversity of microscopic life. Similar investigations by Jan Swammerdam led to new interest in entomology and built the basic techniques of microscopic dissection and staining.Magner, A History of the Life Sciences, pp 133–144 Debate over the flood described in the Bible catalyzed the development of paleontology; in 1669 Nicholas Steno published an essay on how the remains of living organisms could be trapped in layers of sediment and mineralized to produce fossils.

The three procedures are (1) the traditional hand-stripping method, considered to be time-consuming and laborious; (2) Caesarean section, a relatively quick surgical method of extracting eggs through a abdominal incision; considered faster than hand stripping, suturing can be time-consuming and the incision may result in muscular stress and poor suture retention which lowers survival rate; and (3) MIST, (minimally invasive surgical technique) which is the fastest of the three procedures because it requires less handling of the fish and eliminates the need for suturing. A small internal incision is made in the dorsal area of the oviduct, which allows direct stripping of eggs from the body cavity through the gonopore bypassing the oviductal funnels. A spermiating male indicates successful production of mature spermatozoa which results in the release of large volumes of milt over the course of three to four days. Milt is collected by inserting a short plastic tube with syringe attached into the urogenital opening of the male and applying light suction with the syringe to draw the milt.

The chemoattractant secreted from the cumulus cells is the steroid progesterone, shown to be effective at the picomolar range.Teves, M.E., Barbano, F., Guidobaldi, H.A., Sanchez, R., Miska, W. and Giojalas, L.C. (2006) Progesterone at the picomolar range is a chemoattractant for mammalian spermatozoa. Fertil. Steril. 86, 745–749.Oren-Benaroya, R., Orvieto, R., Gakamsky, A., Pinchasov, M. and Eisenbach, M. (2008) The sperm chemoattractant secreted from human cumulus cells is progesterone. Hum. Reprod. 23, 2339–2345.Guidobaldi, H.A., Teves, M.E., Unates, D.R., Anastasia, A. and Giojalas, L.C. (2008) Progesterone from the cumulus cells is the sperm chemoattractant secreted by the rabbit oocyte cumulus complex. PLOS One 3, e3040. The chemoattractant secreted from the oocyte is even more potent. It is a hydrophobic non-peptide molecule which, when secreted from the oocyte, is in complex with a carrier proteinArmon, L., Ben-Ami, I., Ron-El, R. and Eisenbach, M. (2014) Human oocyte-derived sperm chemoattractant is a hydrophobic molecule associated with a carrier protein. Fertil. Steril. 102, 885–890.

Sperm sorting is an advanced technique that sorts sperm "in vitro" by flow cytometry. This shines a laser at the sperm to distinguish X and Y chromosomes, and can automatically separate the sperm out into different samples. During the early to mid 1980s, Dr. Glenn Spaulding was the first to sort viable whole human and animal spermatozoa using a flow cytometer, and utilized the sorted motile rabbit sperm for artificial insemination. Subsequently, the first patent application disclosing the method to sort "two viable subpopulations enriched for x- or y- sperm"US Patent 5,021,244, column 9, Sorting Sperm was filed in April 1987 as US Application Serial Number 35,986 and later became part of US Patent 5,021,244; and the patent included the discovery of haploid expression (sex-associated membrane proteins, or SAM proteins) and the development of monoclonal antibodies to those proteins. Additional applications and methods were added, including antibodies, from 1987 through 1997.US Patent 5,021,244; 5,346,990; 5,369,012; 5,439,362; 5,496,722; 5,648,468; 5,660,997; PCT/US1989/002069 At the time of the patent filing, both Lawrence Livermore National Laboratories and the USDA were only sorting fixed sperm nuclei, after the Application Serial Number 35,986 patent filing a new technique was utilized by the USDA where "sperm were briefly sonicated to remove tails".