Document Detail

Ecdysteroid concentrations through various life-stages of the meiobenthic harpacticoid copepod, Amphiascus tenuiremis and the benthic estuarine amphipod, Leptocheirus plumulosus.
MedLine Citation:
PMID:  12765655     Owner:  NLM     Status:  MEDLINE    
Endocrine function in arthropods has principally been characterized in insects and malacostracan crustaceans. However, meiofauna represent the most abundant metazoan marine taxa, with harpacticoid copepods comprising the second most abundant taxon. In addition, their diminutive biomass has made characterization of endocrine components difficult, so little is known about endocrine control of reproduction, molting, and growth in meiofauna. In this study, a sensitive fluorometric enzyme immunoassay (EIA) was utilized to quantify and compare the arthropod molting hormone, 20-hydroxyecdysone (20E), in various life-cycle and developmental stages of a laboratory reared meiobenthic copepod, Amphiascus tenuiremis, and in an amphipod, Leptocheirus plumulosus. In copepods, gravid females carrying late stage pre-hatch embryos contained significantly more 20E (390+/-252 fmol/female) than gravids carrying early (Stage-I) embryos (172+/-83 fmol/female). In contrast, ecdysteroid levels in Stage-I L. plumulosus gravid females (277+/-83 fmol/female) was greater than pre-hatch gravid females (146+/-42). Stage-I embryos of both copepods (19+/-10) and amphipods (11+/-5 fmol/embryo) possessed lower ecdysteroid content than copepod (35+/-15) and amphipod (43+/-33 fmol/embryo) pre-hatch embryos. Ecdysteroid levels were also assessed in naupliar, juvenile, adult male and non-gravid female copepod life-stages. In addition, ecdysteroids measured in field collected copepod species indicated gravid females possessed ecdysteroid levels similar to gravid A. tenuiremis. However, upon normalization of egg sac 20E content by brood size, embryos from larger broods contained lower levels of ecdysteroids when compared to embryos from smaller clutch sizes-indicating an inverse embryo/ecdysteroid relationship may exist across species.
David S Block; Adriana C Bejarano; G Thomas Chandler
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  General and comparative endocrinology     Volume:  132     ISSN:  0016-6480     ISO Abbreviation:  Gen. Comp. Endocrinol.     Publication Date:  2003 Jun 
Date Detail:
Created Date:  2003-05-26     Completed Date:  2004-01-15     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370735     Medline TA:  Gen Comp Endocrinol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  151-60     Citation Subset:  IM    
Department of Environmental Health Sciences, University of South Carolina, 800 Sumter Street, Room 311, Columbia, SC 29208, USA.
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MeSH Terms
Aging / metabolism*
Amphipoda / growth & development*,  metabolism*
Copepoda / growth & development*,  metabolism*
Ecdysterone / metabolism*
Immunoenzyme Techniques
Osmolar Concentration
Reg. No./Substance:

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