20-Hydroxyecdysone (ecdysterone or 20E) is a naturally occurring ecdysteroid hormone which controls the ecdysis (moulting) and metamorphosis of arthropods. It is therefore one of the most common moulting hormones in insects, crabs, etc. It is also a phytoecdysteroid produced by various plants, including Cyanotis vaga, where its purpose is presumably to disrupt the development and reproduction of insect pests. In arthropods, 20-hydroxyecdysone acts through the ecdysone receptor. Although mammals lack this receptor, 20-hydroxyecdysone may affect mammalian (including human) biological systems in vitro, but there is uncertainty whether any in vivo or physiological effects occur. 20-Hydroxyecdysone is an ingredient of some supplements that aim to enhance physical performance, but there is no clinical evidence for this effect.
|Elimination half-life||4-9 hours|
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The primary sources of 20-hydroxyecdysone in larvae are the prothoracic gland, ring gland, gut, and fat bodies. These tissues convert dietary cholesterol into the mature forms of the hormone 20-hydroxyecdysone. For the most part these glandular tissues are lost in the adult with exception of the fat body, which is retained as a sheath of lipid tissue surrounding the brain and organs of the abdomen. In the adult female the ovary is a substantial source of 20-hydroxyecdysone production. Adult males are left with, so far as is currently known, one source of 20-hydroxyecdysone which is the fat body tissue. These hormone producing tissues express the ecdysone receptor throughout development, possibility indicating a functional feedback mechanism.
An ecdysteroid is a type of steroid hormones in insects that are derived from enzymatic modification of cholesterol by p450 enzymes. This occurs by a mechanism similar to steroid synthesis in vertebrates. Ecdysone and 20-hydroxyecdysone regulate larval molts, onset of puparium formation, and metamorphosis. Being that these hormones are hydrophobic, they traverse lipid membranes and permeate the tissues of an organism. Indeed, the main receptor of these hormone signals - the ecdysone receptor - is an intracellular protein.
20-Hydroxyecdysone and other ecdysteroids are marketed as ingredients in nutritional supplements for various sports, particularly bodybuilding. Evidence to support such use, however, is limited. A comprehensive study, designed to find any strength or athletic improvement from 20-hydroxyecdysone, was published in 2006. The study looked for improvement in actual exercises performed and tested for improvements/increases in chemical indicators such as body composition and free/available testosterone. The results of the 2006 study concluded that using 30 mg per day of 20-hydroxyecdysone administered orally did not significantly affect anabolic or catabolic responses to resistance training, body composition, or training adaptations.
20-Hydroxyecdysone and other ecdysteroids are used in biochemistry research as inducers in transgenic animals, whereby a new gene is introduced into an animal so that its expression is under the control of an introduced ecdysone receptor. Adding or removing ecdysteroids from the animal's diet then gives a convenient way to turn the inserted gene on or off (see ecdysone receptor). At usual doses, 20-hydroxyecdysone appears to have little or no effect on animals that do not have extra genes inserted; it also has high bioavailability when taken orally, so it is useful for determining whether the transgene has been taken up effectively. For uses in gene therapy, it may be necessary to investigate more thoroughly the natural sources of ecdysteroids in humans (which appear to include dietary phytoecdysteroids, gut flora, helminth infections, and other diseases).
There is some in vitro evidence to show that 20-hydroxyecdysone has effects on some kinds of blood cells such as lymphocytes and neutrophils, and may act as an immunomodulator. This would explain the mechanism behind Helminthic therapy due to the production of ecdysteroids by helminths, as mentioned above.
Aparna Dutta Gupta is an Indian scientist and professor. She teaches in the Department of Animal Biology, School of Life Sciences, University of Hyderabad. Her research is on zoology, developmental biology and endocrinology. She has carried out research in the field of insect physiology, focusing on pests and their control. Her novel contribution includes that insect fat body expresses hexamerin genes, and the expressed proteins are sequestered by various tissues including male accessory-glands and play a role in reproduction.
Prof. Aparna Dutta Gupta, born on 11 th May 1953, obtained her bachelors, masters and doctoral degrees from Banaras Hindu University. She has trained a large number of postgraduate students and mentored more than 25 Ph.D students. She was Fulbright Scholar (1984-1985), Indo-German Exchange Programme Fellow (1991), INSA-Czech Academy Exchange Fellow (2000), DST-DAAD Personal Exchange Fellow (1999–2003), INSA-DFG International Exchange Fellow (2008) and INSA-JSPS Bilateral Exchange Fellow (2012). She is also an elected Fellow of Indian National Science Academy (FNA), Indian Academy of Sciences (FASc), and The National Academy of Sciences (FNASc).Bracken
Bracken (Pteridium) is a genus of large, coarse ferns in the family Dennstaedtiaceae. Ferns (Pteridophyta) are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells (eggs and sperm). Brackens are noted for their large, highly divided leaves. They are found on all continents except Antarctica and in all environments except deserts, though their typical habitat is moorland. The genus probably has the widest distribution of any fern in the world.
In the past, the genus was commonly treated as having only one species, Pteridium aquilinum, but the recent trend is to subdivide it into about ten species.
Like other ferns, brackens do not have seeds or fruits, but the immature fronds, known as fiddleheads, are sometimes eaten, although some are thought to be carcinogenic (see Poisoning).
The word bracken is of Old Norse origin, related to Swedish bräken and Danish bregne, both meaning fern.Choriogenesis
In developmental biology, choriogenesis is the formation of the chorion, an outer membrane of the placenta that eventually forms chorionic villi that allow the transfer of blood and nutrients from mother to fetus.Dominance hierarchy
Dominance hierarchy is a type of social hierarchy that arises when members of a social group interact, to create a ranking system. In social living groups, members are likely to compete for access to limited resources and mating opportunities. Rather than fighting each time they meet, relative rank is established between members of the same sex. Based on repetitive interactions a social order is created that is subject to change each time a dominant animal is challenged by a subordinate one.Ecdysone
Ecdysone is a steroidal prohormone of the major insect molting hormone 20-hydroxyecdysone, which is secreted from the prothoracic glands. Insect molting hormones (ecdysone and its homologues) are generally called ecdysteroids. Ecdysteroids act as moulting hormones of arthropods but also occur in other related phyla where they can play different roles. In Drosophila melanogaster, an increase in ecdysone concentration induces the expression of genes coding for proteins that the larva requires, and it causes chromosome puffs (sites of high expression) to form in polytene chromosomes. Recent findings in the laboratory of Chris Q. Doe have found a novel role of this hormone in regulating temporal gene transitions within neural stem cells of the fruit fly. Ecdysone and other ecdysteroids also appear in many plants mostly as a protection agent (toxins or antifeedants) against herbivorous insects.These phytoecdysteroids have been reputed to have medicinal value and are part of herbal adaptogenic remedies like Cordyceps, yet an ecdysteroid precursor in plants has been shown to have cytotoxic properties.Tebufenozide, sold under the Bayer trademark MIMIC, has ecdysteroid activity although its chemical structure has little resemblance to the ecdysteroids.Ecdysone 20-monooxygenase
Ecdysone 20-monooxygenase (EC 126.96.36.199) is an enzyme that catalyzes the chemical reaction
The 3 substrates of this enzyme are ecdysone, an electron acceptor AH2, and O2, whereas its 3 products are 20-hydroxyecdysone, the reduction product A, and H2O.
This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derive from O miscellaneous. The systematic name of this enzyme class is Ecdysone,hydrogen-donor:oxygen oxidoreductase (20-hydroxylating). Other names in common use include alpha-ecdysone C-20 hydroxylase, and ecdysone 20-hydroxylase.Ecdysone receptor
The ecdysone receptor is a nuclear receptor found in arthropods, where it controls development and contributes to other processes such as reproduction. The receptor is a non-covalent heterodimer of two proteins, the EcR protein and ultraspiracle protein (USP). It binds to and is activated by ecdysteroids. Insect ecdysone receptors are currently better characterized than those from other arthropods, and mimics of ecdysteroids are used commercially as caterpillar-selective insecticides.Ecdysteroid
Ecdysteroids are arthropod steroid hormones that are mainly responsible for molting, development and, to a lesser extent, reproduction; examples of ecdysteroids include ecdysone, ecdysterone, turkesterone and 20-hydroxyecdysone. These compounds are synthesized in arthropods from dietary cholesterol upon metabolism by the Halloween family of cytochrome P450s. Phytoecdysteroids also appear in many plants mostly as a protection agents (toxins or antifeedants) against herbivore insects.Facetotecta
Facetotecta is a poorly known infraclass of thecostracan crustaceans. The adult forms have never been recognised, and the group is known only from its larvae, the "y-nauplius" and "y-cyprid" larvae. They are mostly found in the north Atlantic Ocean, neritic waters around Japan, and the Mediterranean Basin, where they also survive in brackish water.Glossary of biology
Most of the terms listed in Wikipedia glossaries are already defined and explained within Wikipedia itself. However, glossaries like this one are useful for looking up, comparing and reviewing large numbers of terms together. You can help enhance this page by adding new terms or writing definitions for existing ones.
This glossary of biology terms is a list of definitions of fundamental terms and concepts of biology, its sub-disciplines, and related fields. For more specific definitions from other glossaries related to biology, see Glossary of ecology, Glossary of botany, Glossary of genetics, and Glossary of speciation.Halloween genes
The halloween genes are a set of genes identified in Drosophila melanogaster that influence embryonic development. All of the genes code for cytochrome P450 enzymes in the ecdysteroidogenic pathway (biosynthesis of ecdysone from cholesterol). Ecdysteroids such as 20-hydroxyecdysone and ecdysone influence many of the morphological, physiological, biochemical changes that occur during molting in insects.Steroid hormones control many aspects of reproduction, development, and homeostasis in higher organisms. In arthropods, steroid hormones play equal or even more vital developmental roles, especially in controlling the patterns of gene expression between developmental stages.First elaborated by research groups led by Wieschaus and Nüsslein-Volhard in the early 1980s, the name was coined to collectively name a series of Drosophila embryonic lethal mutations associated with defective exoskeleton formation. Early research showed that when one of the Halloween genes was mutated, fly embryos would die before the exoskeleton was created. Mutants in the halloween gene series include the spook, spookier, phantom (or phm), disembodied (or dib), shadow (or sad), and shade genes.Hemolin
Hemolin is an immunoglobulin-like protein exclusively found in Lepidoptera (moths and butterflies). It was first discovered in immune-challenged pupae of Hyalophora cecropia and Manduca sexta.Hemolin has a horseshoe crystal structure with four domains and resembles the developmental protein neuroglian.
Hemolin increases 18-fold up to 7 mg/ml following injection of bacteria in H. cecropia. Induction of Hemolin in moths after bacterial injection have been shown in several species including Antheraea pernyi, Bombyx mori, Helicoverpa zea, Heliothis virescens, Hyphantria cunea, and Samia cynthia.Hemolin has also been suggested to participate in the immune response to virus infection and shown to bind to virus particles. It is expressed in response to dsRNA in a dose-dependent manner. Galleria melonella responds to caffeine intake by increased Hemolin protein expression.Hemolin is thought to be a gene duplication of the developmental protein neuroglian, but has lost two of the protein domains that neuroglian contains. In the potential function as a developmental protein, Hemolin has been shown to increase close to pupation in Manduca sexta, and is induced during diapause and by 20-Hydroxyecdysone in Lymantria dispar. RNAi of Hemolin causes malformation in H. cecropia.Iris clarkei
Iris clarkei is a species in the genus Iris, also the subgenus of Limniris and in the Iris series Sibiricae. It is a rhizomatous herbaceous perennial, from Asia, including north east India, Nepal, Tibet, Bhutan, Burma and in China. It has grey-green leaves, long and thin green stem and violet, to dark blue, to blue or reddish purple flowers.Lymantria dispar multicapsid nuclear polyhedrosis virus
Lymantria dispar multicapsid nuclear polyhedrosis virus or LdMNPV is a viral infection in gypsy moths (Lymantria dispar) that causes infected larvae to die and disintegrate. Infected larvae climb to the top of a tree and die. The larvae then melt or disintegrate, falling onto the foliage below, where they infect more larvae.
Often referred to as Gypchek, the virus goes by multiple names. Gypchek is an insecticide which uses the virus to control the gypsy moth population. Because the virus only infects Lymantria dispar, it has proven safe for use with other insects including ants, bees and non-target lepidopteran species. Studies of its safety have found no toxicity or mortality concerns, though ocular doses administered to rabbits did cause some irritation.
The gene responsible for the behavior of infected larvae has been found to be egt (codes ecdysteroid UDP-glucosyltransferase), with the protein tyrosine phosphatase (PTP) playing a role in the infection of brain tissue. Due to the virus' effect on the infected larvae, various reports of zombie caterpillars popularized the virus at the time of the discovery of the egt gene.Prothoracic gland
The prothoracic glands are either of a pair of endocrine glands located in the prothorax of certain insects that regulate molting. They have an ectodermal origin and secrete ecdysteroids, such as ecdysone and 20-hydroxyecdysone.Rhaponticum carthamoides
Rhaponticum carthamoides, also known as Maral root or Rhaponticum, is an herbaceous perennial plant from the family Asteraceae that inhabits the sub-alpine zone (4,500–6,000 ft (1,400–1,800 m) above sea level) as well as alpine meadows. It can be found growing wild in Southern Siberia, Kazakhstan, the Altay region, and Western Sayan Mountains. Maral root is widely cultivated throughout Russia and Eastern Europe. This plant derives its traditional name Maral root (Maralu) from the maral deer who fed on it.
Animal studies indicate that maral root may have a beneficial effect on memory and learning in rats, increasing working capacity of tired skeletal muscles, as well as anabolic and adaptogenic processes in rats.R. carthamoides is high in 20-hydroxyecdysone, one of the most common molting hormones in insects, crabs, and some worms and 20E can disrupt their molting and reproduction.Triterpenoid saponin
Triterpenoid saponins are triterpenes which belong to the group of saponin compounds. Triterpenes are a type of terpene containing 30 carbon atoms. Triterpenes are assembled from a five-carbon isoprene unit through the cytosolic mevalonate pathway to make a thirty-carbon compound. Some triterpenes are steroidal in nature. Cholesterol, phytosterols and phytoecdysteroids are triterpenes. The triterpenes are subdivided into some 20 groups, depending on their particular structures. Some triterpenoid compounds are found as saponin glycosides which refers to the attachment of various sugar molecules to the triterpene unit. These sugars can be cleaved off in the gut by bacteria, sometimes allowing the aglycone (triterpene) to be absorbed into the bloodstream or to insert into cell membranes.Saponin glycosides reduce surface tension of water with foaming and will break down lipids. Usually triterpene saponins are designated as such by the suffix ending –side, such as ginsenoside or astragaloside, named for the plant genera they were first discovered in. Some, such as the ginsenosides and eleutherosides are designated Rx where the suffix x = a, a1, b2, is indicative of
the relative position of the saponin spots from top to bottom of a thin layer chromatogram.