Dauer is a German word meaning "enduring" and is used to describe an alternative developmental stage of nematodes, particularly Caenorhabditis elegans. The German language (de ''Deutsch'') is a West Germanic language and one of the world's major languages. The nematodes or roundworms ( Phylum Nematoda from Greek (nema "thread" + -ode "like" are one of the most common Caenorhabditis elegans (ˌsiːnoʊræbˈdaɪtɪs ˈɛlɪgænz is a free-living Nematode (roundworm about 1 mm in length which It is also considered by some to be equivalent to the infective stage of parasitic nematode larvae. Parasitism is a type of symbiotic relationship between Organisms of different Species. A larva ( Latin; plural larvae) is a juvenile form of Animal with indirect development, undergoing Metamorphosis (for example Under environmental conditions that are favorable for reproduction, larvae develop through 4 stages or molts which are designated as L1, L2, L3 and L4. After L4, animals moult to the reproductive adult stage. Ecdysis is the Molting of the Cuticula in Arthropods and related groups ( Ecdysozoa) However, when the environment is unfavorable, L1 and L2 animals have the option to divert their development from reproduction to dauer formation. Signals such as temperature, food supply, and a dauer-inducing pheromone (population density cue) influence this dauer decision. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature A pheromone (from Greek φέρω phero "to bear" + ‘ορμόνη " Hormone " is a Chemical that triggers a natural Dauer larvae are thus considered an alternative L3 stage larva, and this stage is sometimes referred to as L2d. L2d animals are also considered pre-dauer and are characterised by delayed development and dark intestines produced by storage of fat. Dauer larvae are extensively studied by biologists because of their ability to survive harsh environments and live for extended periods of time. Dauer formation in C. elegans requires a nuclear receptor DAF-12 and a forkhead transcription factor DAF-16. In the field of Molecular biology, a transcription factor (sometimes called a sequence-specific DNA binding factor is a Protein that binds to specific sequences In favorable environments, DAF-12 is activated by a steroid hormone produced by the cytochrome p450, DAF-9. A steroid is a Terpenoid Lipid characterized by a Carbon skeleton with four fused rings generally arranged in a 6-6-6-5 fashion Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body Cytochrome P450 (abbreviated CYP, P450, infrequently CYP450) is a very large and diverse superfamily of Hemoproteins found in all Domains Interestingly, DAF-9 and DAF-12 have been implicated by Cynthia Kenyon and colleagues as being required for extended longevity seen in animals that lack germlines. In Biology and Genetics, the germline of a mature or developing individual is the line (sequence of Germ cells that have genetic material that
The Dauer state is given other names in the various types of nematodes such as ‘diapause’ , ‘hyperbobis’, ‘spring rise’, but since the C. elegans nematode has become the most studied nematode, the term ‘dauer stage’ or 'dauer larvae' is becoming universally recognised when referring to this state in other nematodes.
A characteristic of the dauer stage is the pronounced alae (Alae (anatomy)) which may be implicated in the entering (L1) and exiting (pre adult or L4 in C. The alae is a protruding ridge that forms longitudinally on many Nematodes. elegans) of the dauer stage
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