Abstract
Ecdysteroid: member of a class of polyhydroxylated steroids found in invertebrate animals (zooecdysteroids; moulting hormones), plants (phytoecdysteroids) and fungi (mycoecdysteroids). Over 500 structural analogues are currently known. Biosynthetically, they derive from C27-, C28- or C29-sterols. The most frequently encountered analogue (in arthropods and plants) is 20-hydroxyecdysone (2β,3β,14α,20R,22R,25-hexahydroxycholest-7-en-6-one). In arthropods, ecdysteroids occur universally and regulate development by inducing moulting and reproduction, where their action is mediated by high-affinity binding to an intracellular member of the class of nuclear receptor (NR) proteins (ecdysteroid receptor; EcR) dimerised with a second NR (USP/RxR). This receptor complex binds to specific DNA promoter sites and regulates gene expression. In plants, ecdysteroids are a class of secondary compounds, occurring in varying amounts in certain species, but not all in others. Phytoecdysteroids are believed to contribute to the reduction of invertebrate predation by acting as feeding deterrents or endocrine disruptors. Ecdysteroids also possess a wide range of positive pharmacological effects in mammals, where the mode of action involves moderate-affinity binding to plasma-membrane-bound receptors and not interaction with the classical NRs for vertebrate steroid hormones.
Highlights
Academic Editor: Łukasz StepieńReceived: 2 October 2021Accepted: 24 November 2021Published: 1 December 2021Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Licensee MDPI, Basel, Switzerland.This Entry is dedicated to the memory of Prof
The presence of ecdysteroids in plants was first determined by several groups alThe presence of ecdysteroids in plants was first determined by several groups almost simultaneously, shortly after the final unambiguous elucidation of the structure of most simultaneously, shortly after the unambiguous elucidation of the structure of ecdysone from Bombyx mori pupae
Chlorella vulgaris [52,53] and growth and heterocyst formation in the cyanobacterium Nostoc [54]. Such effects may be related to the stimulation of the activity of the photosynthetic enzyme RuBisCO by 20E, AjuC and PolB, demonstrated in vitro for the enzyme isolated from Tetragonia tetragonoides (New Zealand spinach; [55])
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Ecdysteroids are a family of invertebrate steroid hormones that are involved in the regulation of moulting, development and reproduction [1] They differ significantly in their structure from vertebrate steroid hormones since they are characteristically polyhydroxylated, generally retain the full sterol carbon skeleton, possess a 14α-hydroxy-7-en-6-one chromophoric group located in the B-ring and possess an A/B-cis-ring junction. 537 natural ecdysteroid analogues have been most of which have been isolated only from plants, probably in large part because of the identified (Ecdybase [4]), most which have some been isolated only from plants, probably in higher concentrations found in of plant sources; are found in invertebrates and plants, large part because of the higher concentrations found in plant sources; some are found and a few have only, so far, been detected in invertebrates. In invertebrates and plants, and a few have only, so far, been detected in invertebrates
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