VEAZEY LASSEIGNE, J; LANDRY, CA; LAFLEUR, JR, GJ; Nicholls State University, Thibodaux, LA: Biomarkers of oogenesis as molecular tools for conservation biology

Louisiana is currently losing an acre of coastal wetlands every 30 minutes. To reverse this natural disaster, large-scale restoration activities are being proposed which will divert water and sediments from the Mississippi River to the nearby swamps and marshes of the Barataria Terrebonne National Estuary. A persistent question is whether these water diversions will introduce endocrine disrupting agents that may adversely affect wildlife. To address this our lab is assaying the reproductive health of wetland species within the estuary to provide a basis for comparisons before and after diversions are opened. We have concentrated our efforts on the development of biomarkers to assess hallmarks of oogenesis such as the synthesis of yolk and egg envelope proteins. Using sequence information previously obtained from the east coast mummichog Fundulus heteroclitus, we have designed molecular tools to probe local species including the Gulf killifish Fundulus grandis, the freshwater cyprinodontiforms Fundulus chrysotus and Gambusia affinis, and the aquatic salamander Amphiuma tridactylum. We present evidence that our protocols are suitable for isolating heterologous vitellogenin cDNAs from normally cycling females and estrogen-induced males in both fish and amphibians. Preliminary data suggests that while choriogenins are synthesized by the livers of fish, the orthologous envelope proteins in amphibians are synthesized by the ovary. Whether estrogen-induction plays a role in the gonadal synthesis of amphiuma envelope proteins remains to be elucidated. In conclusion, our RT-PCR methods for amplifying reproductive biomarkers has provided us with material for basic comparative studies in reproduction as well as offering a method to assess reproductive health in wildlife exposed to environmental stressors including endocrine disruption.