Chemical Control of Moulting in Arthropods

Krishnakumaran, A.; Schneiderman, Howard A.

doi:10.1038/220601a0

Cited by 57 publications

(7 citation statements)

References 7 publications

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“…Although the direct administration of 20E has previously been used in many crustacean studies, some reported high mortality rates during premolt (Krishnakumaran and Schneideman, 1968;Skinner, 1985), whereas others reported successful viable ecdysis (Dall and Barclay, 1977;Gilgan and Burns, 1977;Webster, 1983). The failure to obtain viable ecdysis may be attributed to incorrect dosage of 20E -too high or too lowneeded in each specific molt stage.…”

Section: Discussionmentioning

confidence: 89%

Search for hepatopancreatic ecdysteroid-responsive genes during the crayfish molt cycle: from a single gene to multigenicity

Shechter

Tom

Yudkovski

et al. 2007

Journal of Experimental Biology

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SUMMARY The expression of the vitellogenin gene of the red-claw crayfish Cherax quadricarinatus (CqVg) was previously demonstrated in male crayfish during an endocrinologically induced molt cycle. The hypothesis that this expression is under the direct control of ecdysteroids was tested in this study both in vivo and in vitro. Unlike vitellogenin of insects, CqVg was not found to be ecdysteroid-responsive. Thus, a multigenic approach was employed for the identification of other hepatopancreatic ecdysteroid-responsive genes by a cDNA microarray. For the purposes of this study, a multi-parametric molt-staging technique, based on X-ray detection of gastrolith growth, was developed. To identify ecdysteroid-responsive genes during premolt, the molt cycle was induced by two manipulations, 20-hydroxyecdysone administration and X-organ–sinus gland complex removal; both resulted in significant elevation of ecdysteroids. Two clusters of affected genes (129 and 122 genes, respectively) were revealed by the microarray. It is suggested that only genes belonging to similarly responsive (up- or downregulated) gene clusters in both manipulations (102 genes) could be considered putative ecdysteroid-responsive genes. Some of these ecdysteroid-responsive genes showed homology to genes controlling chitin metabolism, proteases and other cellular activities, while 56.8% were unknown. The majority of the genes were downregulated, presumably by an energetic shift of the hepatopancreas prior to ecdysis. The effect of 20-hydroxyecdysone on representative genes from this group was confirmed in vitro using a hepatopancreas tissue culture. This approach for ecdysteroid-responsive gene identification could also be implemented in other tissues for the elucidation of ecdysteroid-specific signaling pathways during the crustacean molt cycle.

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Section: Discussionmentioning

confidence: 89%

Search for hepatopancreatic ecdysteroid-responsive genes during the crayfish molt cycle: from a single gene to multigenicity

Shechter

Tom

Yudkovski

et al. 2007

Journal of Experimental Biology

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“…In arthropods, moulting is a hormone‐controlled process with ecdysteroids acting as the main regulatory hormones (Krishnakumaran & Schneiderman, ; Richards, ). Ecdysteroids exert their effect through a defined set of nuclear receptors (Nakagawa & Henrich, ; Yamamoto & Alberts, ) triggering regulatory cascades by activating early and late response genes (Ashburner & Richards, ; Riddiford, Hiruma, Lan, & Zhou, ; Thummel, , , ; White, Hurban, Watanabe, & Hogness, ).…”

Section: Introductionmentioning

confidence: 99%

RNA sequencing reveals distinct gene expression patterns during the development of parasitic larval stages of the salmon louse (Lepeophtheirus salmonis)

Eichner

Dondrup

Nilsen

2018

Journal of Fish Diseases

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The salmon louse (Lepeophtheirus salmonis), an ectoparasitic copepod on salmonids, has become a major threat for the aquaculture industry. In search for new drugs and vaccines, transcriptome analysis is increasingly used to find differently regulated genes and pathways in response to treatment. However, the underlying gene expression changes going along with developmental processes could confound such analyses. The life cycle of L. salmonis consists of eight stages divided by moults. The developmental rate of salmon lice on the host is not uniform. Individual- and sex-related differences are found leading to individuals of unlike developmental status at same sampling time point after infection. In this study, we analyse L. salmonis from a time series by RNA sequencing applying a method of separating individuals of different instar age independent of sampling time point. Lice of four stages divided into up to four age groups within the stage were analysed in triplicate (total of 66 samples). Gene expression analysis shows that the method for sorting individuals was successful. Many genes show cyclic expression patterns over the moulting cycles. Overall gene expression differs more between lice of different age within the same stage than between lice of different stage but same instar age.

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“…The synthesis of tritiated a-ecdysone of high specific activity (5) provided the critical tool for studies on the binding of molting hormone to arthropod target systems. We now know that a-ecdysone is rapidly converted to ,3-ecdysone (ecdysterone, 20-hydroxyecdysone, crustecdysone) by insects and crustaceans (6,7), and it is believed that j3-ecdysone is the molting hormone of crustaceans (8)(9)(10)(11). The present study examines the possibility of hormone-binding macromolecules in the crayfish hepatopancreas, an organ analogous to the vertebrate liver and the insect fat body.…”

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confidence: 99%

Binding Proteins for an Ecdysone Metabolite in the Crustacean Hepatopancreas

Gorell

Gilbert

Siddall

1972

Proc. Natl. Acad. Sci. U.S.A.

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When crustacean hepatopancreas is incubated in the presence of a-[3Hlecdysone of high specific activity and is then homogenized and centrifuged, a peak of protein-radioactivity is recovered after gel filtration of the 105,000 X g supernatant. Analysis of this peak by sucrose gradient centrifugation revealed the presence of two complexes of protein and labeled material (-11.5 S and 6.35 S). The same results were obtained in vivo. On standing at low ionic strength, the lighter component disappeared, suggesting that the heavier component is an aggregate of the lighter one. Chemical analysis of radioactive material in the complex revealed that it is not a-or j3-ecdysone nor any previously described metabolite of the ecdysones.This new metabolite of a-ecdysone is found mainly in the incubated hepatopancreas. Partial structures consistent with the analytical data are inferred for this metabolite. It is suggested that the metabolite may be active in the action of molting hormone.Although highly significant advances regarding the chemical nature of arthropod growth hormones have occurred in recent years (1, 2), we do not yet fully understand how these molecules elicit their effects. This lack of understanding is due in part to a paucity of information regarding the primary step in hormone action, i.e., the means by which the hormone recognizes the target tissue (or the converse) and is "bound" to cell constituents. The existence of proteins that bind steroid hormones is an established fact in several mammalian systems (3, 4), and progress in that field is due in great part to the synthesis of labeled hormones of high specific activity. The synthesis of tritiated a-ecdysone of high specific activity (5) provided the critical tool for studies on the binding of molting hormone to arthropod target systems. We now know that a-ecdysone is rapidly converted to ,3-ecdysone (ecdysterone, 20-hydroxyecdysone, crustecdysone) by insects and crustaceans (6, 7), and it is believed that j3-ecdysone is the molting hormone of crustaceans (8-11). The present study examines the possibility of hormone-binding macromolecules in the crayfish hepatopancreas, an organ analogous to the vertebrate liver and the insect fat body. MATERIALS AND METHODSThe a-[23,24-8H]ecdysone was synthesized by catalytic tritiation of 2,,3(3,14a,22,,25-pentahydroxy-5(3-cholest-7-en-23-yn-6-one (5). Male crayfish (Orconectes virilis) were cooled on ice for 30 min, and the hepatopancreas was removed. The hepatopancreas was rinsed in crayfish saline (12) and incubated at 250 in 3 ml of saline containing [8H]ecdysone (see figure legends for quantities). After incubation, the tissue was rinsed twice in cold 0.1 M phosphate buffer (pH 7.3) and homogenized in buffer in a ground glass homogenizer at 4°. After centrifugation of the homogenate at 105,000 X g for 1.5hr at 40, the supernatant was concentrated with lyphogel and aliquots of the concentrated supernatant were assayed for protein (13) The hepatopancreas is rich in lipid (14, 15), which necessitated partial...

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Chemical Control of Moulting in Arthropods

Cited by 57 publications

References 7 publications

Search for hepatopancreatic ecdysteroid-responsive genes during the crayfish molt cycle: from a single gene to multigenicity

Search for hepatopancreatic ecdysteroid-responsive genes during the crayfish molt cycle: from a single gene to multigenicity

RNA sequencing reveals distinct gene expression patterns during the development of parasitic larval stages of the salmon louse (Lepeophtheirus salmonis)

Binding Proteins for an Ecdysone Metabolite in the Crustacean Hepatopancreas

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