Tag: Moulting
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Moulting was known as mewing in medieval times
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer layer or covering), either at specific times of the year, or at specific points in its life cycle. In medieval times it was also…
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Mews derives from the French muer, ‘to moult’
A mews is a row or courtyard of stables and carriage houses with living quarters above them, built behind large city houses before motor vehicles replaced horses in the early twentieth century. Mews are usually located in desirable residential areas, having been built to cater for the horses, coachmen and stable-servants of prosperous residents. The word mews comes from the Royal Mews in London, England,…
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PPARGC1A is also known as human accelerated region 20 (HAR20) and may have played a key role in differentiating humans from apes
Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a protein that in humans is encoded by the PPARGC1A gene. PPARGC1A is also known as human accelerated region 20 (HAR20). It may, therefore, have played a key role in differentiating humans from apes. PGC-1α is the master regulator of mitochondrial biogenesis. PGC-1α is also the primary regulator of liver gluconeogenesis, inducing increased gene expression for gluconeogenesis. Function PGC-1α is a super…
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20-Hydroxyecdysone, ecdysteroid hormone which controls the ecdysis (moulting) and metamorphosis of arthropods
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, Ajuga turkestanica and Rhaponticum carthamoides 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…
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Prothoracicotropic hormone (PTTH) formerly known as “brain hormone”
Prothoracicotropic hormone (PTTH) was the first insect hormone to be discovered. The chemical symbol for prothoracicotropic hormone is (C64H102N16O19S2). It was originally described simply as “brain hormone” by early workers such as Stefan Kopeć (1922) and Vincent Wigglesworth (1934), who realized that ligation of the head of immature insects could prevent molting or pupation of the body region excluded from the head if the ligation was performed before a critical…
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Phytoecdysteroids are plant-derived ecdysteroids
Phytoecdysteroids are plant-derived ecdysteroids. Phytoecdysteroids are a class of chemicals that plants synthesize for defense against phytophagous (plant eating) insects. These compounds are mimics of hormones used by arthropods in the molting process known as ecdysis. When insects eat the plants with these chemicals they may prematurely molt, lose weight, or suffer other metabolic damage and die. Chemically,…
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The 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…
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Chrysolina beetles, including Chrysolina coerulans, have cardiac glycosides (including xylose) in their defensive glands
The defensive secretions of some chrysomelid beetles belonging to the genera Chrysolina, Chrysochloa, and Dlochrysa contain complex mixtures of cardenolides. The spectral data for some of these compounds suggest that they are monohydroxylated digitoxigenin derivatives linked to a pentose (such as xylose or arabinose). Evidence indicates that the beetles do not sequester these steroid glycosides…
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Gastrolith
A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In other species the rocks are ingested and pass through the digestive system and are frequently replaced. The grain size depends upon the size of the animal and…
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Katydids have the biggest balls of all
Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as “long-horned grasshoppers”. More than 8,000 species are known. Part of the suborder Ensifera, the Tettigoniidae are the only extant (living) family in the superfamily Tettigonioidea. They are primarily nocturnal in habit with strident mating calls. Many species exhibit mimicry and camouflage, commonly with shapes and colors similar to leaves. Etymology The family…
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Prolactin (PRL)
In mammals, prolactin is associated with milk production; in fish it is thought to be related to the control of water and salt balance. Prolactin also acts in a cytokine-like manner and as an important regulator of the immune system. It has important cell cycle-related functions as a growth-, differentiating- and anti-apoptotic factor. As a growth factor,…
