Here's a rundown of the companies in their own words: aXenic is a global leader in the design, development and production of optical modulators for communications and sensing.
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In biology, axenic describes the state of a culture in which only a single species, variety, or strain of organism is present and entirely free of all other contaminating organisms. The earliest axenic cultures were of bacteria or unicellular eukaryotes, but axenic cultures of many multicellular organisms are also possible. Axenic culture is an important tool for the study of symbiotic and parasitic organisms in a controlled environment.
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This work was important in the development of axenic culture methods.
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Such "contaminating" organisms will grow on the plate during this period, identifying cultures that are no longer axenic.
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Other medium recommended for axenic culture are Proteose Peptone-yeast extract-glucose medium, and Trypticase soy broth medium.
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Amoebidium appalachense was also obtained in axenic culture, and subsequent molecular analyses supported its relationship with A. parasiticum and other Mesomycetozoea.
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Production of DMS from dissolved DMSP in axenic cultures of the marine phytoplankton species Phaeocystis sp., Mar. Ecol. Prog. Ser. 97, 11 –18.
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The two vegetative cell types, amoebae and plasmodia, differ markedly in morphology, physiology and behavior. Amoebae are microorganisms, typically haploid, that live primarily in the soil, where they phagocytose bacteria. In the laboratory amoebae are grown on lawns of live or dead Escherichia coli on nutrient agar plates, where they can multiply indefinitely. Axenic culture of amoebae was achieved through selection of mutants capable of axenic growth.
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In the 1990s a group of high school students in New Hampshire made progress on axenic culture from seed and were able to obtain over 50% germination levels in about 3 weeks.Sokolski K. & Peter Faletra (1997). Growth Studies of the Showy Lady Slipper (Cypripedium reginae) in Axenic Seed Culture, Bulletin of America Association for the Advancement of Sciences, Annual meeting, pp. A-112AAAS Annual Meeting, Programs and Abstracts, 1998 Efforts at micropropagation have had marginal success.
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Axenic cultures of microorganisms are typically prepared by subculture of an existing mixed culture. This may involve use of a dilution series, in which a culture is successively diluted to the point where subsamples of it contain only a few individual organisms, ideally only a single individual (in the case of an asexual species). These subcultures are allowed to grow until the identity of their constituent organisms can be ascertained. Selection of those cultures consisting solely of the desired organism produces the axenic culture.
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Subculture selection may also involve manually sampling the target organism from an uncontaminated growth front in an otherwise mixed culture, and using this as an inoculum source for the subculture. Axenic cultures are usually checked routinely to ensure that they remain axenic. One standard approach with microorganisms is to spread a sample of the culture onto an agar plate, and to incubate this for a fixed period of time. The agar should be an enriched medium that will support the growth of common "contaminating" organisms.
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Axenic Cell culture of the plant Physcomitrella patens on an agarplate in a Petri dish Petri dishes may be used to observe the early stages of plant germination, and to grow plants asexually from isolated cells.
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Therefore, axenic cultures of trichomycetes are highly valuable for obtaining pure DNA samples. As a result, the phylogenetic position of A. parasiticum was finally resolved in 2000 when molecular phylogenetic analysesBenny, G. L., and O'Donnell, K. 2000. Amoebidium parasiticum is a protozoan, not a Trichomycete. Mycologia 92: 1133-1137.
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The microbiota seem to affect the lifespan of Drosophila melanogaster. To date, the mechanisms of this effect remain elusive. Fruit flies raised under axenic conditions (i.e., without any bacteria in the environment) or cured of their microbiota with antibiotics had a shorter lifespan than flies raised under normal conditions.
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The ATCC maintains a collection of Blastocystis isolates. Some records show whether the isolates were obtained from symptomatic or asymptomatic carriers. As yet, no publication has identified the subtypes of most of the ATCC isolates, which are mostly axenic. Researchers have reported that patients with Irritable bowel syndrome may provide a reliable source for xenic Blastocystis isolates.
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Cypripedium reginae, known as the showy lady's slipper, pink-and-white lady's-slipper, or the queen's lady's-slipper, is a rare lady's-slipper orchid native to northern North America. Although never common, this plant has vanished from much of its historical range due to habitat loss.Sokolski et al. (1997). "Axenic Seed Culture and Micropropagation of Cypripedium reginae" Selbyana 18(2): 172-182.
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Amoebidium parasiticum was the first trichomycete (a group of microscopic fungi and protists found in symbiotic association with aquatic arthropods) to be obtained in axenic culture, allowing for detailed studies of its nutritional requirements,Whisler, H. C. 1962. Culture and nutrition of Amoebidium parasiticum. American Journal of Botany 49: 193-199. cell wall composition,Trotter, M. J., and Whisler, H. C. 1965.
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The axenic culture of some pathogens is complicated because they normally thrive within host tissues which exhibit properties that are difficult to replicate in vitro. This is especially true in the case of intracellular pathogens. However, careful replication of key features of the host environment can resolve these difficulties (e.g. host metabolites, dissolved oxygen), such as with the Q fever pathogen, Coxiella burnetii.
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The original Micromonas reference genome was created from a strain, RCC299, first isolated in 1998 from an Equatorial Pacific sample. This strain has been continuously cultured for two decades and is available from the Roscoff Culture Collection. In 2005, a monoclonal culture of the strain was isolated. The axenic strain is available from the Center for Culture of Marine Phytoplankton, under the name CCMP2709.
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Phycotoxins production may be useful to ward off parasitic or algicidal heterotrophic bacteria. Some evidence of anti-microbial effects: #Bates et al. was able to enhance domoic acid production in Pseudo-nitzschia multseries with the re-introduction of bacteria. Additionally, P. multiseries cultures which were completely axenic (bacteria-free), produce less domoic acid than P. multiseries cultures which have contained bacteria for several generations.
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An axenic culture of TM7 from the oral cavity was reported in 2014 but no sequence or culture was made available. Along with Candidate Phylum TM6, it was named after sequences obtained in 1994 in an environmental study of a soil sample of peat bog in Germany where 262 PCR amplified 16S rDNA fragments were cloned into a plasmid vector, named TM clones for ' (lit. peat, middle layer).
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Internal hatching is initiated by genes and is not restricted to the widely used laboratory strain N2. Internal hatching is rare when worms are maintained under standard laboratory conditions. However, axenic condition which is a transfer from solid to liquid medium along with adverse environmental conditions, such as starvation, exposure to harsh compounds, and bacteria can increase the frequency of worm bags. In a study C. elegans were starved and in stressful conditions such as a high salt environment.
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B. quintana is a fastidious, aerobic, Gram-negative(-), pole rod-shaped (bacillus) bacterium. The infection caused by this microorganism, trench fever, was first documented in soldiers during World War I, but has now been seen Europe, Asia, and North Africa. Its primary vector is known to be Pediculus humanus variety corporis, also known as the human body louse. It was first known to be isolated in axenic culture by J.W. Vinson in 1960, from a patient in Mexico City.
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Various Penicillium, Aspergillus spp. and other fungi growing in axenic culture Historical model of Aspergillus, Botanical Museum Greifswald Species of Aspergillus are important medically and commercially. Some species can cause infection in humans and other animals. Some infections found in animals have been studied for years, while other species found in animals have been described as new and specific to the investigated disease, and others have been known as names already in use for organisms such as saprophytes.
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They also reported a similar behavior in Dictyostelium. Since E. histolytica does not form cysts in the absence of bacteria, E. invadens has become used as a model for encystation studies as it will form cysts under axenic growth conditions, which simplifies analysis. After inducing encystation in E. invadens, DNA replication increases initially and then slows down. On completion of encystation, predominantly tetra-nucleate cysts are formed along with some uni-, bi- and tri-nucleate cysts.
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The lolines are the most abundant alkaloids, with concentrations 1000 higher than those of ergot alkaloids. Endophyte-free grasses do not produce lolines, and, as shown for the closely related endophyte commonly occurring in meadow fescue, Neotyphodium uncinatum, the endophyte can produce lolines in axenic laboratory culture. However, although N. coenophialum possesses all the genes for loline biosynthesis, it does not produce lolines in culture. So in the tall fescue symbiosis, only the interaction of the host and endophyte produces the lolines.
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As axenic cultures are derived from very few organisms, or even a single individual, they are useful because the organisms present within them share a relatively narrow gene pool. In the case of an asexual species derived from a single individual, the resulting culture should consist of identical organisms (though processes such as mutation and horizontal gene transfer may introduce a degree of variability). Consequently, they will generally respond in a more uniform and reproducible fashion, simplifying the interpretation of experiments.
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C. elegans was first described in 1900 by Émile Maupas, who isolated it from soil in Algeria. Ellsworth Dougherty proposed in 1948 that free-living nematodes of the sub-order Rhabditina might be useful for genetic study, noting their relative structural simplicity and invariant cell lineage (eutely). Dougherty and Victor Nigon obtained the first mutant, from a laboratory culture of the closely related nematode Caenorhabditis briggsae. However much of the early laboratory work on Caenorhabditis nematodes was directed towards the establishment of a defined axenic culture medium.
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It was also argued that the evidence from studies using germ-free offspring of axenic animals (germ-free) clearly showed the sterility of the uterus. The authors concluded that in light of these findings there was no existence of a microbiome. The normal dominance of Lactobacilli in the vagina is seen as a marker for vaginal health. However, in the uterus this much lower population is seen as invasive in a closed environment that is highly regulated by female sex hormones, and that could have unwanted consequences.
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N. fowleri can be grown in several kinds of liquid axenic media or on non-nutrient agar plates coated with bacteria. Escherichia coli can be used to overlay the non-nutrient agar plate and a drop of cerebrospinal fluid sediment is added to it. Plates are then incubated at 37 °C and checked daily for clearing of the agar in thin tracks, which indicate the trophozoites have fed on the bacteria. Detection in water is performed by centrifuging a water sample with E. coli added, then applying the pellet to a non-nutrient agar plate.
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The antibiotic susceptibility was determined using a single strain of M. pusilla with the purpose to produce axenic cultures to be used in studies and experiments. The strain of M.pusilla was tested with a range of antibiotics to determine the possible effects of the particular antibiotic. Resistance: benzylpenicillin, gentamicin, kanamycin, neomycin, streptomycin Sensitive: chloramphenicol, polymyxin B For M. pusilla, sensitivity towards an antibiotic is likely defined by the impairment of growth, rather than a lethal effect, when subjected to bactericidal levels of that particular antibiotic. The susceptibility of other strains of M. pusilla towards this set of antibiotics should be the same.
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Mycena galopus is a saprobic fungus, and plays an important role in forest ecosystems as a decomposer of leaf litter. It has been estimated in the UK to account for a large portion of the decomposition of the autumn leaf litter in British woodlands. It is able to break down the lignin and cellulose components of leaf litter. Grown in axenic culture in the laboratory, the fungus mycelium has been shown to degrade (in addition to lignin and cellulose) hemicelluloses, protein, soluble carbohydrates, and purified xylan and pectin using enzymes such as polyphenol oxidases, cellulases, and catalase.
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For example, a throat culture is taken by scraping the lining of tissue in the back of the throat and blotting the sample into a medium to be able to screen for harmful microorganisms, such as Streptococcus pyogenes, the causative agent of strep throat. Furthermore, the term culture is more generally used informally to refer to "selectively growing" a specific kind of microorganism in the lab. It is often essential to isolate a pure culture of microorganisms. A pure (or axenic) culture is a population of cells or multicellular organisms growing in the absence of other species or types.
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The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI). The phylogeny is based on 16S rRNA-based LTP release 132 by The All-Species Living Tree Project Notes: ♠ Strains found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LSPN). ♪ Prokaryotes where no pure (axenic) cultures are isolated or available; i.e., they are not cultivated or cannot be sustained in culture for more than a few serial passages.
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Around the same time, Derrick proposed the name Rickettsia burnetii, in recognition of Burnet's contribution in identifying the organism as a Rickettsia. As it became clear that the species differed significantly from other Rickettsia, it was first elevated to a subgenus named after Cox, Coxiella, and then in 1948 to its own genus of that name, proposed by Cornelius B. Philip, another RML researcher. Coxiella was difficult to study because it could not be reproduced outside a host. However, in 2009, scientists reported a technique allowing the bacteria to grow in an axenic culture and suggested the technique may be useful for study of other pathogens.
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Escobar grew cultures of the fungus by placing fresh fruit bodies on agar containing growth medium with an extract of horse dung. The tips of the hyphae were used to obtain axenic cultures; the fungus can grow on a variety of media commonly used to grow fungi in the laboratory. Depending on the composition of the growth media, fruit bodies were formed as early as eight days after initiating, when grown at and under dim light. When minute agar blocks containing mycelium were submerged in distilled water, mycelial strands grew towards the water surface and eventually gave rise to floating fruit bodies connected to the parent agar block by strands of hyphae.
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However, they were unable to induce the new organism to grow on artificial media, and did not definitively establish a teleomorph-anamorph connection between the fungi. In 2009, Japanese researchers found a similar fungus growing on rotting logs that were normally associated with the growth of C. geaster; they were able to grow the organism in axenic cultures from single-spore isolates of C. geaster. Until the one fungus, one name rule was enacted in 2011, the International Code of Botanical Nomenclature permitted the recognition of two (or more) names for one and the same organism, one based on the teleomorph, the other(s) restricted to the anamorph(s). So Nagao et al.
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There, and during travels around the globe, he performed research on the axenic culture of nematodes, nematode parasites of insects and the fossil records of insects and nematodes in amber. In 1992 a team consisting of Poinar, his wife entomologist Roberta Poinar, his son Hendrik, and Dr. Raúl J. Cano of California Polytechnic State University successfully extracted insect DNA from a Lebanese weevil in amber that was 125 million years old, collected by Raif Milki in Lebanon. More recent studies of ancient DNA cast doubt on the DNA results, but not on the authenticity of the amber samples. In 1995, George and Roberta Poinar, a fellow researcher from Berkeley, moved to Oregon, where they opened the Amber Institute.
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In the field, to the eye, Loreleia is most similar to Rickenella because of the orangish colors and omphalinoid shape, but microscopically it differs by the absence of cystidia that in Rickenella make the latter minutely fuzzy as seen with a hand lens. Loreleia penetrates the rhizoids of liverworts and may form a type of symbiosis with them, but in axenic culture tests, L. marchantiae killed Marchantia polymorpha when directly inoculated in contrast to the absence of necrosis in nature in situ. In nature Loreleia often occur in wet areas such as seepages with their hosts, Marchantia. Older literature often treats the species, like L. postii and L. marchantiae, in the genera Omphalina or Gerronema.
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Winogradsky posited that pleomorphists Naegli and Zopf were unable to perceive the existence of bacterial morphological classes, and that Cohn and Koch, within their own suppositions, ignore species of morphologically variant bacteria that are unable to grow within axenic cultures. Winogradsky explained the perception of pleomorphic bacteria as bacteria progressing through different stages within a developmental cycle, thereby providing the fundamental structure for a theory of morphology based upon the concept of dynamic deviation from a morphological type, or biotype. Coxiella burnetii bacteria displaying pleomorphism While the pleomorphic debate still exists in its original form to some extent, it has predominantly been altered to a discussion regarding the methods, evolutionary inception, and practical applications of pleomorphism. Many modern scientists regard pleomorphism as either a bacterium's response to pressure exerted by environmental factors, such as bacteria that shed antigenic markers in the presence of antibiotics, or as an occurrence in which bacteria evolve successively more complicated forms.
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