High impact information on Ecdysterone

• Induction of acetylcholinesterase activity by beta-ecdysone in a Drosophila cell line [1].
• At the onset of Drosophila metamorphosis, the steroid hormone 20-OH ecdysone directly induces a small number of early puffs in the polytene chromosomes of the larval salivary gland [2].
• In vitro incubation of discs with beta-ecdysone, juvenile hormone, or cycloheximide resulted in increased activity of RNA polymerase I. The increase was irreversible with beta-ecdysone incubation and removal but reversible with juvenile hormone incubation and removal [3].
• With beta-ecdysone, the rate of the increase in polymerase I activity paralleled the kinetics of ecdysone binding to discs and increases in the rate of precursor incorporation into RNA [3].
• Modulation of novel-length DOPA decarboxylase transcripts by 20-OH-ecdysone in a Drosophila melanogaster Kc cell subline [4].

Biological context of Ecdysterone

• Bovine thyroglobulin is succinylated and the succinylated protein is coupled to beta-ecdysone with 1-ethyl-3-(-dimethylaminopropyl)-carbodiimide in the presence of the acylation catalyst 4-dimethylaminopyridine, The antiserum obtained using this immunogen provides a radioimmunoassay sensitive to 25 pmol of beta-ecdysone [5].
• A study of the tissue distribution in larvae revealed that 75B mRNA is present in most, if not all 20-OH-ecdysone target tissues [6].
• Molecular study of the retrovirus-like transposable element 412, a 20-OH ecdysone responsive repetitive sequence in Drosophila cultured cells [7].
• 20-OH-ecdysone regulates 60 C beta tubulin gene expression in Kc cells and during Drosophila development [8].
• 1. The C-20 hydroxylation of alpha-ecdysone to produce beta-ecdysone was investigated in the desert locust, Schistocerca gregaria [9].

Anatomical context of Ecdysterone

• Selective activation of RNA polymerase I in fat body nuclei of Sarcophaga peregrina larvae by beta-ecdysone [10].
• Amiloride, a blocker of plasma membrane Na+/H+ exchange, prevented 20-OH-ecdysone-induced nuclear swelling [11].
• Injection of ovariectomized females with beta-ecdysone restored the ability of the fat cells to produce the secretion granules [12].
• In the present work, parasitization and injection of CxF (0.5 female equivalent) on the first day of the last stadium both prevented the rise in hemolymph 20-hydroxyecdysone (20HE) titer observed between day 4 and day 7 in control and saline-injected larvae [13].
• 20 (OH) Ecdysone-induced alteration of protein biosynthesis and secretion by the hypodermis of the crayfish Astacus leptodactylus was studied using isolated tissues in vitro [14].

Associations of Ecdysterone with other chemical compounds

• This increase in DDC activity was prevented by infusion of 20-hydroxyecdysone (20HE) into the larva, indicating that the fall of the ecdysteroid titer is necessary for the increase [15].
• Some subclones, selected in the presence of 20-OH-ecdysone, are resistant only to molting hormone, but still respond to RH 5992 morphologically and biochemically, whereas subclones selected in the presence of the benzoylhydrazine showed no reaction neither to 20-OH-ecdysone nor to the hormone agonist [16].
• From these cultures, subclones were selected, which are resistant to up to 25 microM 20-OH-ecdysone according to morphological (changes in cell shape and cell arrangement) and physiological criteria (acetylcholinesterase induction, secretion of chitinolytic enzymes, thymidine incorporation) [16].
• Methoprene and 20-OH-ecdysone affect male production in Daphnia pulex [17].
• The effect of precocene II and 20-OH-ecdysone on Litomosoides carinii and Dipetalonema viteae in vivo [18].

Gene context of Ecdysterone

• Exposure of the mature larval epidermis to 20-OH-ecdysone caused a rapid accumulation of DDC transcripts [19].
• It is proposed that the activity of the 20-OH-ecdysone inducible puff 74EF leads to a switch in the synthesis of a transcription factor [20].
• We identified in Dictyostelium a gene snwA containing a region of similarity to SH2 domains of higher eukaryotes. snwA is homologous to a novel human gene SNW1 and to Bx42 from Drosophila melanogaster, a gene coding for a chromatin binding protein responsive to 20-OH-ecdysone. snwA has one mRNA transcript of an approximate size of 2.5 kb [21].
• These results are discussed in terms of a model in which beta-ecdysone affects the distribution of tubulin in "assembly-active" and "assembly-inactive" pools [22].
• Ecdysterone increases the level of the P1 transcript, but not of the P6 transcript, in ecdysterone-deficient ecd1 larvae [23].

Analytical, diagnostic and therapeutic context of Ecdysterone

• Separation and detection of alpha- and beta-ecdysone using thin-layer chromatography [24].
• Measurements of pH in salivary gland cells with ion-sensitive microelectrodes disclosed an alkalinization of 0.23 +/- 0.05 pH units after stimulation with 20-OH-ecdysone [11].
• During the embryonic stage C the ratio of 20-OH-ecdysone to ecdysone was shown by HPLC analysis to steadily increase [25].
• At 1 day after addition of 1-microM 20-OH-ecdysone (20E) total immunofluorescence had increased in the nuclei, whereas the cytoplasmic staining had disappeared [26].
• Further, beta-ecdysone is the only endogenous ecdysone detected by high pressure liquid chromatography during larval-pupal development [27].

References