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Nematode Worms (Caenorhabditis Elegans): Difference between revisions
Nematode Worms (Caenorhabditis Elegans) (view source)
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[[File:Adult_Caenorhabditis_elegans.jpg|alt=|right|frameless]] | [[File:Adult_Caenorhabditis_elegans.jpg|alt=|right|frameless]] | ||
'''''Caenorhabditis elegans''''' is a free-living transparent nematode about 1 mm in length<ref> | '''''Caenorhabditis elegans''''' is a free-living transparent nematode about 1 mm in length<ref> | ||
{{cite book | last = Wood | first = WB | year = 1988 | title = The Nematode ''Caenorhabditis elegans'' | page = 1 | publisher = [[Cold Spring Harbor Laboratory Press]] | isbn = 978-0-87969-433-3 }}</ref> that lives in temperate soil environments. It is the type species of its genus.<ref>{{cite journal |doi=10.1111/j.1439-0469.1996.tb00827.x |title=Phylogeny of ''Rhabditis'' subgenus ''Caenorhabditis'' (Rhabditidae, Nematoda) |journal=Journal of Zoological Systematics and Evolutionary Research |volume=34 |issue=4 |pages=217–233 |year=2009 | vauthors = Sudhaus W, Kiontke K }}</ref> The name is a blend of the Greek ''caeno-'' (recent), ''rhabditis'' (rod-like)<ref>καινός (caenos) = new, recent; ῥάβδος (rhabdos) = rod, wand.</ref> and Latin ''elegans'' (elegant). In 1900, Maupas initially named it ''Rhabditides elegans.'' Osche placed it in the subgenus ''Caenorhabditis'' in 1952, and in 1955, Dougherty raised ''Caenorhabditis'' to the status of genus.<ref> | {{cite book | last = Wood | first = WB | year = 1988 | title = The Nematode ''Caenorhabditis elegans'' | page = 1 | publisher = [[Cold Spring Harbor Laboratory Press]] | isbn = 978-0-87969-433-3 }}</ref> that lives in temperate soil environments. It is the type species of its genus.<ref>{{cite journal |doi=10.1111/j.1439-0469.1996.tb00827.x |title=Phylogeny of ''Rhabditis'' subgenus ''Caenorhabditis'' (Rhabditidae, Nematoda) |journal=Journal of Zoological Systematics and Evolutionary Research |volume=34 |issue=4 |pages=217–233 |year=2009 | vauthors = Sudhaus W, Kiontke K }}</ref> The name is a blend of the Greek ''caeno-'' (recent), ''rhabditis'' (rod-like)<ref>καινός (caenos) = new, recent; ῥάβδος (rhabdos) = rod, wand.</ref> and Latin ''elegans'' (elegant). In 1900, Maupas initially named it ''Rhabditides elegans.'' Osche placed it in the subgenus ''Caenorhabditis'' in 1952, and in 1955, Dougherty raised ''Caenorhabditis'' to the status of genus.<ref> | ||
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Research has explored the neural and molecular mechanisms that control several behaviors of ''C. elegans'', including chemotaxis, thermotaxis, mechanotransduction, learning, memory, and mating behaviour.{{pmid|16139205}} In 2019 the connectome of the male was published using a technique distinct from that used for the hermaphrodite. The same paper used the new technique to redo the hermaphrodite connectome, finding 1,500 new synapses.{{pmid|31270481}} | Research has explored the neural and molecular mechanisms that control several behaviors of ''C. elegans'', including chemotaxis, thermotaxis, mechanotransduction, learning, memory, and mating behaviour.{{pmid|16139205}} In 2019 the connectome of the male was published using a technique distinct from that used for the hermaphrodite. The same paper used the new technique to redo the hermaphrodite connectome, finding 1,500 new synapses.{{pmid|31270481}} | ||
It has been used as a model organism to study molecular mechanisms in metabolic diseases.{{pmid|29990370}} Brenner also chose it as it is easy to grow in bulk populations, and convenient for genetic analysis.<ref>{{cite web |last=Avery |first=L |title=Sydney Brenner |url=http://elegans.swmed.edu/Sydney.html |publisher=[[Southwestern Medical Center]] |url-status=dead |archive-url=https://web.archive.org/web/20110815143145/http://elegans.swmed.edu/Sydney.html |archive-date=August 15, 2011 }} [http://elegans.som.vcu.edu/Sydney.html Alt. URL] {{Webarchive|url=https://web.archive.org/web/20131208060434/http://elegans.som.vcu.edu/Sydney.html |date=2013-12-08 }}</ref> It is a multicellular eukaryotic organism, yet simple enough to be studied in great detail. The transparency of ''C. elegans'' facilitates the study of cellular differentiation and other developmental processes in the intact organism. The spicules in the male clearly distinguish males from females. Strains are cheap to breed and can be frozen. When subsequently thawed, they remain viable, allowing long-term storage. | It has been used as a model organism to study molecular mechanisms in metabolic diseases.{{pmid|29990370}} Brenner also chose it as it is easy to grow in bulk populations, and convenient for genetic analysis.<ref>{{cite web |last=Avery |first=L |title=Sydney Brenner |url=http://elegans.swmed.edu/Sydney.html |publisher=[[Southwestern Medical Center]] |url-status=dead |archive-url=https://web.archive.org/web/20110815143145/http://elegans.swmed.edu/Sydney.html |archive-date=August 15, 2011 }} [http://elegans.som.vcu.edu/Sydney.html Alt. URL] {{Webarchive|url=https://web.archive.org/web/20131208060434/http://elegans.som.vcu.edu/Sydney.html |date=2013-12-08 }}</ref> It is a multicellular eukaryotic organism, yet simple enough to be studied in great detail. The transparency of ''C. elegans'' facilitates the study of cellular differentiation and other developmental processes in the intact organism. The spicules in the male clearly distinguish males from females. Strains are cheap to breed and can be frozen. When subsequently thawed, they remain viable, allowing long-term storage.{{pmid|4366476}} Maintenance is easy when compared to other multicellular model organisms. A few hundred nematodes can be kept on a single agar plate and suitable growth medium. Brenner described the use of a mutant of ''E. coli'' – OP50. OP50 is a uracil-requiring organism and its deficiency in the plate prevents the overgrowth of bacteria which would obscure the worms.{{pmid|4366476}} The use of OP50 does not demand any major laboratory safety measures, since it is non-pathogenic and easily grown in Luria-Bertani (LB) media overnight.<ref>{{Cite web|url=http://www.wormbook.org/chapters/www_behavior/behavior.html#sec1|title=Behavior|website=www.wormbook.org|access-date=2018-09-26}}</ref> | ||
===Ageing=== | ===Ageing=== | ||
''C. elegans'' has been a model organism for research into ageing; for example, the inhibition of an insulin-like growth factor signaling pathway has been shown to increase adult lifespan threefold;{{pmid|11021802}}{{pmid|25517099}} while glucose feeding promotes oxidative stress and reduce adult lifespan by a half. | ''C. elegans'' has been a model organism for research into ageing; for example, the inhibition of an insulin-like growth factor signaling pathway has been shown to increase adult lifespan threefold;{{pmid|11021802}}{{pmid|25517099}} while glucose feeding promotes oxidative stress and reduce adult lifespan by a half.{{pmid|29990370}} Similarly, induced degradation of an insulin/IGF-1 receptor late in life extended life expectancy of worms dramatically.{{pmid|34505574}} Long-lived mutants of ''C. elegans'' were demonstrated to be resistant to oxidative stress and UV light.{{pmid|18203746}} These long-lived mutants had a higher DNA repair capability than wild-type ''C. elegans''.{{pmid|18203746}} Knockdown of the nucleotide excision repair gene Xpa-1 increased sensitivity to UV and reduced the life span of the long-lived mutants. These findings indicate that DNA repair capability underlies longevity. | ||
The capacity to repair DNA damage by the process of nucleotide excision repair declines with age.{{pmid|17472752}} | The capacity to repair DNA damage by the process of nucleotide excision repair declines with age.{{pmid|17472752}} | ||