Woods Hole Oceanographic Institution

Tim Verslycke

»Copepod diapause
»Lobster Shell Disease
»Crustacean molting receptor
»Lobster Shell Disease
»Mysids as test models for endocrine disruption testing
»Chlorotriazines in the Scheldt estuary
»Energy allocation in grasshopper
»Estrogens in Scheldt estuary
»Marsupial development in mysids to evaluate endocrine disruption
»B[a]P effects on steroid metabolism in mysid
»Ciona CYP3 genes
»Methoprene, nonylphenol, and estrone effects on mysid vitellogenesis
»Methoprene effects on mysid molting
»Mysid growth
»Mysid vitellin ELISA
»Mysid vitellin
»An analytical method to detect estrogens in water
»High levels of endocrine disruptors in wild mysid populations
»Energy allocation in wild mysid populations
»Cellular energy allocation validation with scope for growth
»Dolphin delivery prediction
»PhD thesis
»Endocrine disruptor effects on steroid and energy metabolism in mysid
»Mysid review
»TBT effects on steroid metabolism in mysid
»Metal mixture toxicity to mysid
»TBT effects on energy metabolism in mysid
»dichlorobenzene effects in zebrafish
»Ethinylestradiol effects on amphipod sexual development
»Metabolic studies with mysids
»Abiotic stress and energy metabolism in mysid
»Induced vitellogenesis in rainbow trout
»Steroid metabolism in mysid
»Endocrine disruption in freshwater snails
»Invasive mysid in Belgium

An Ghekiere, Tim Verslycke, Nancy Fockedey, Colin Janssen, Non-target effects of the insecticide methoprene on molting in the estuarine crustacean Neomysis integer (Crustacea: Mysidacea), Journal of Experimental Marine Biology and Ecology 332(2): 226-234, 2006

Ecdysteroids, the molting hormones in crustaceans and other arthropods, play a crucial role in the control of growth, reproduction and embryogenesis of these organisms. Insecticides are often designed to target specific endocrine-regulated functions such as molting and larval development such as methoprene, a juvenile hormone analogue.  The aim of this study was to examine the effects of methoprene on molting in a non-target species, the estuarine mysid Neomysis integer (Crustacea: Mysidacea). Mysids have been proposed as standard test organisms for evaluating the endocrine disruptive effect of chemicals. Juveniles (< 24 h) were exposed for 3 weeks to the nominal concentrations 0.01, 1 and 100 μg methoprene/l. Daily, present molts were checked and stored in 4% formaldehyde for subsequent growth measurements. Methoprene significantly delayed molting at 100 μg/l by decreasing the growth rate and increasing the intermolt period. This resulted in a decreased wet weight of the organism. The anti-ecdysteroidal properties of methoprene on mysid molting were also evaluated by determining the ability of exogenously administered 20-hydroxyecdysone, the active ecdysteroid in crustaceans, to protect against the observed methoprene effects. Co-exposure to 20-hydroxyecdysone did not mitigate methoprene effects on mysid molting. This study demonstrates the need for incorporating invertebrate-specific hormone-regulated endpoints in regulatory screening and testing programs for the detection of endocrine disruption caused by man-made chemicals.

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