Meeting Abstract
P3.54 Monday, Jan. 6 15:30 The effects of toxicants on the production of ecdysteroids by the Y-organ in Callinectes sapidus RYAN, LM*; BRANDER, SM; CHANG, ES; CHANG, SA; COVI, JA; University of North Carolina Wilmington; University of North Carolina Wilmington; Bodega Bay Marine Laboratory, University of California Davis; Bodega Bay Marine Laboratory, University of California Davis; University of North Carolina Wilmington lmr8506@uncw.edu
Over 80,000 chemicals are registered for use in the U. S., many of which remain in the marine environment. Because of their economic importance, the blue crab, Callinectes sapidus, is an important model organism in which to study the effects of endocrine disrupting chemicals on decapod growth. Blue crabs grow by undergoing a series of molts, which involve shedding of the exoskeleton, and growing into a new larger exoskeleton. Molting events are initiated by the synthesis and release of ecdysteroid hormones from the Y-organ (YO). Peptide hormones produced in the eyestalk ganglia (ESG), inhibit molting during intermolt periods. We are assessing the effect of toxicants on the release of ecdysteroids from the YO. Blue crabs were collected from four sites, with differing levels of polluted runoff, in North and South Carolina. Hemolymph was taken within 24 hours of capture for ecdysteroid analysis. YOs were then excised from the crabs and incubated in media with and without ESG for various incubation times. Ecdysteroid concentrations were measured in the culture media to determine basal secretion of by the organs and responsiveness to eyestalk ganglia extract. Preliminary results show that there is no significant difference in basal or ESG extract inhibited ecdysteroid secretion in crabs among the collection sites. In a separate study, we analyzed the secretion of ecdysteroids by YOs from crabs after controlled exposure to toxicants found in estuarine environments. Under the conditions used, Y-organs continued secreting ecdysteroids at a constant rate for at least 28 hours. Exposures to methoprene and bifenthrin within this time frame will be presented.
