|
Dauer Larvae
Dauer (German "''die Dauer''", English "the enduring", "the duration" in the meaning of "a length of time",) describes an alternative developmental stage of nematode worms, particularly rhabditids including ''Caenorhabditis elegans'', whereby the larva goes into a type of stasis and can survive harsh conditions. Since the entrance of the dauer stage is dependent on environmental cues, it represents a classic and well studied example of polyphenism. The dauer state is given other names in the various types of nematodes such as ‘ diapause’ or ‘hypobiosis’, 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 free-living nematodes. The dauer stage is also considered to be equivalent to the infective stage of parasitic nematode larvae. As E. Maupas first proposed in 1899-1900, all nematodes have five stages separated by four moults. Und ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
German Language
German ( ) is a West Germanic languages, West Germanic language mainly spoken in Central Europe. It is the most widely spoken and Official language, official or co-official language in Germany, Austria, Switzerland, Liechtenstein, and the Italy, Italian province of South Tyrol. It is also a co-official language of Luxembourg and German-speaking Community of Belgium, Belgium, as well as a national language in Namibia. Outside Germany, it is also spoken by German communities in France (Bas-Rhin), Czech Republic (North Bohemia), Poland (Upper Silesia), Slovakia (Bratislava Region), and Hungary (Sopron). German is most similar to other languages within the West Germanic language branch, including Afrikaans, Dutch language, Dutch, English language, English, the Frisian languages, Low German, Luxembourgish, Scots language, Scots, and Yiddish. It also contains close similarities in vocabulary to some languages in the North Germanic languages, North Germanic group, such as Danish lan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription Factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The function of TFs is to regulate—turn on and off—genes in order to make sure that they are expressed in the desired cells at the right time and in the right amount throughout the life of the cell and the organism. Groups of TFs function in a coordinated fashion to direct cell division, cell growth, and cell death throughout life; cell migration and organization (body plan) during embryonic development; and intermittently in response to signals from outside the cell, such as a hormone. There are up to 1600 TFs in the human genome. Transcription factors are members of the proteome as well as regulome. TFs work alone or with other proteins in a complex, by promoting (as an activator), or blocking (as a repressor) the recruitment of RNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elytra
An elytron (; ; , ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometimes alternatively spelled as "hemielytra"), and in most species only the basal half is thickened while the apex is membranous, but when they are entirely thickened the condition is referred to as "coleopteroid". An elytron is sometimes also referred to as a shard. Description The elytra primarily serve as protective wing-cases for the hindwings underneath, which are used for flying. To fly, a beetle typically opens the elytra and then extends the hindwings, flying while still holding the elytra open, though many beetles in the families Scarabaeidae and Buprestidae can fly with the elytra closed (e.g., most Cetoniinae; ). In a number of groups, the elytra are reduced to various degrees, (e.g., the beetle families Staphylinidae and Ripiphoridae), or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phoresis
Phoresis or phoresy is a non-permanent, commensalistic interaction in which one organism (a phoront or phoretic) attaches itself to another (the host) solely for the purpose of travel. Phoresis has been observed directly in ticks and mites since the 18th century, and indirectly in fossils 320 million years old. It is not restricted to arthropods or animals; plants with seeds that disperse by attaching themselves to animals are also considered to be phoretic. ''Phoresis'' is rooted in the Greek words ''phoras'' (bearing) and ''phor'' (thief). The term, originally defined in 1896 as a relationship in which the host acts as a vehicle for its passenger, clashed with other terminology being developed at the time, so constraints on the length of time, feeding and ontogeny are now considered. Phoresis is used as a strategy for dispersal, seasonal migration, transport to new host/habitat escaping ephemeral habitats, and reducing inbreeding depression. In addition to the bene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alae (anatomy)
The alae is a protruding ridge that forms longitudinally on many nematodes. In the ''Caenorhabditis elegans'' nematode they are present in the L1, dauer (an alternative long living larvae stage where the nematode is dormant) and adult stages. The alae are most pronounced during the dauer larval stage and not present in the L2, and L3 ''C. elegans'' stages. The term ‘alae’ is the plural of ala (wing), describing either one of the pair of ridges that forms on a nematode or an individual crease found on an individual ridge. The term ‘ala’ is rarely used in describing the alae and scientific journals use the term ‘alae’ both singularly and in the plural. Structure The alae is formed by the hypodermal seam cells where a fibrous ribbon of a zona pellucida (ZP) domain protein is produced. In ''C. elegans'' many of these proteins are termed CUT-1. The CUT refers to cuticulins which are the various proteins that are not solubilised by both reducing agents and detergents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proceedings Of The National Academy Of Sciences Of The United States Of America
''Proceedings of the National Academy of Sciences of the United States of America'' (often abbreviated ''PNAS'' or ''PNAS USA'') is a peer-reviewed multidisciplinary scientific journal. It is the official journal of the National Academy of Sciences, published since 1915, and publishes original research, scientific reviews, commentaries, and letters. According to ''Journal Citation Reports'', the journal has a 2021 impact factor of 12.779. ''PNAS'' is the second most cited scientific journal, with more than 1.9 million cumulative citations from 2008 to 2018. In the mass media, ''PNAS'' has been described variously as "prestigious", "sedate", "renowned" and "high impact". ''PNAS'' is a delayed open access journal, with an embargo period of six months that can be bypassed for an author fee ( hybrid open access). Since September 2017, open access articles are published under a Creative Commons license. Since January 2019, ''PNAS'' has been online-only, although print issues are ava ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Life Extension
Life extension is the concept of extending the human life expectancy, lifespan, either modestly through improvements in medicine or dramatically by increasing the maximum lifespan beyond its generally-settled oldest people, limit of 125 years. Several researchers in the area, along with "life extensionists", "immortalists" or "longevists" (those who wish to achieve longer lives themselves), postulate that future breakthroughs in tissue rejuvenation (aging), rejuvenation, stem cells, regenerative medicine, molecular repair, gene therapy, pharmaceuticals and organ (anatomy), organ replacement (such as with artificial organs or xenotransplantations) will eventually enable humans to have indefinite lifespans (agerasia) through complete rejuvenation to a healthy youthful condition. The ethical ramifications, if life extension becomes a possibility, are debated by bioethicists. The sale of purported anti-aging products such as supplements and hormone replacement is a lucrative global i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germline
In biology and genetics, the germline is the population of a multicellular organism's cells that pass on their genetic material to the progeny (offspring). In other words, they are the cells that form the egg, sperm and the fertilised egg. They are usually differentiated to perform this function and segregated in a specific place away from other bodily cells. As a rule, this passing-on happens via a process of sexual reproduction; typically it is a process that includes systematic changes to the genetic material, changes that arise during recombination, meiosis and fertilization for example. However, there are many exceptions across multicellular organisms, including processes and concepts such as various forms of apomixis, autogamy, automixis, cloning or parthenogenesis. The cells of the germline are called germ cells. For example, gametes such as a sperm and an egg are germ cells. So are the cells that divide to produce gametes, called gametocytes, the cells that produce thos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cynthia Kenyon
Cynthia Jane Kenyon (born February 21, 1954) is an American molecular biologist and biogerontologist known for her genetic dissection of aging in a widely used model organism, the roundworm ''Caenorhabditis elegans''. She is the vice president of aging research at Calico Research Labs, and emeritus professor of biochemistry and biophysics at the University of California, San Francisco (UCSF). Career Cynthia Kenyon graduated valedictorian in chemistry and biochemistry from the University of Georgia in 1976. She received her Ph.D. in 1981 from MIT where, in Graham Walker's laboratory, she looked for genes on the basis of their activity profiles, discovering that DNA-damaging agents activate a battery of DNA repair genes in E. coli. She then did postdoctoral studies with Nobel laureate Sydney Brenner at the MRC Laboratory of Molecular Biology in Cambridge, England, studying the development of ''C. elegans.'' Since 1986 she has been at the UCSF, where she was the Herbert Boyer Dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DAF-9
The Daf-9 gene encodes a cytochrome p450 enzyme catalysis the generation of dafachronic acid (a steroid hormone) in the worm ''Caenorhabditis elegans'', with the CYP Symbol CYP22A1 (Cytochrome P450, family 22, member A1). After generation, dafachronic acid will binding it's nuclear receptor Daf-12 and has been implicated by Cynthia Kenyon and colleagues related to the formation of Dauer larva Dauer (German "''die Dauer''", English "the enduring", "the duration" in the meaning of "a length of time",) describes an alternative developmental stage of nematode worms, particularly rhabditids including '' Caenorhabditis elegans'', whereby the .... References {{Dauer larva Caenorhabditis elegans genes 22 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome P450
Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance (pharmacology), clearance of various compounds, as well as for hormone synthesis and breakdown. In 1963, Ronald W. Estabrook, Estabrook, David Y. Cooper, Cooper, and Otto Rosenthal, Rosenthal described the role of CYP as a catalyst in steroid hormone synthesis and drug metabolism. In plants, these proteins are important for the biosynthesis of secondary metabolite, defensive compounds, fatty acids, and hormones. CYP enzymes have been identified in all kingdom (biology), kingdoms of life: animals, plants, fungus, fungi, protists, bacteria, and archaea, as well as in viruses. However, they are not omnipresent; for example, they have not been found in ''Escherichia coli''. , more than 300,000 distinct CYP proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dafachronic Acid
Dafachronic acids are steroid hormones activate the nuclear receptor Daf-12/NR1J1 in ''Caenorhabditis elegans'' and related organisms, include Δ4-dafachronic acid and Δ7-dafachronic acid. Both are generated by Daf-9 The Daf-9 gene encodes a cytochrome p450 enzyme catalysis the generation of dafachronic acid (a steroid hormone) in the worm ''Caenorhabditis elegans'', with the CYP Symbol CYP22A1 (Cytochrome P450, family 22, member A1). After generation, dafachro .../CYP22A1 from respective precursors. References {{Reflist Steroid hormones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
