Detailed project information for Study Plan Number 02116

Branch :	Aquatic Ecology Branch
Study Plan Number :	02116
Study Title :	Effects of estrogen and related contaminants on the expression of genes involved in the innate immune system of fish in rivers of the Chesapeake Bay Drainage
Starting Date :	12/01/2006
Completion Date :	12/30/2009
Principal Investigator(s) :	Robertson, Laura S and Iwanowicz, Luke R.
Primary PI :	Robertson, Laura S
Telephone Number :	(304) 724-4579
Email Address :	lrobertson@usgs.gov
SIS Number :
Primary Program Element :
Second Program Element :
Status :	Active
Abstract :	BACKGROUND Recent fish kills and fish lesions have occurred in the Potomac and Shenandoah Rivers concurrent with a high prevalence of intersex. The presence of oocytes in the testes of male fish is an indicator of exposure to estrogenic compounds. The coincidence of intersex and fish lesions suggests that fish in these rivers are exposed to estrogenic compounds and that this exposure disrupts the immune function of fish. Previous work by Vicki Blazer and colleagues indicates that there is no single pathogen responsible for these recent fish kills and fish lesions, suggesting a general decline in the immune system. These fish kills involve smallmouth bass, sunfish, and northern hogsuckers [1]. Smallmouth bass are both a very popular gamefish and a sensitive indicator of water quality. Largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu) are very closely related species. The frequency of intersex and lesions is much less in largemouth bass than smallmouth bass and largemouth bass have not been involved in the recent fish kills in the Potomac and Shenandoah Rivers. OBJECTIVES 1. Measure hepcidin and iNOS expression in large and smallmouth bass exposed to bacteria and exposed to estrogen, nonylphenol, or Potomac River sediment extracts. Are hepcidin expression and iNOS expression induced upon exposure to bacteria? Is this induction blocked by estrogen, nonylphenol, or Potomac River sediment extracts? 2. Measure gene expression of hepcidin and iNOS in wild-caught smallmouth bass from the Shenandoah and Potomac Rivers, where fish kills have occurred, and in wild-caught smallmouth bass from out-of-basin rivers. Is expression of hepcidin and iNOS in fish from the Shenandoah and Potomac Rivers different from expression in fish from out-of-basin rivers? Are there similarities between expression patterns of hepcidin and iNOS in fish exposed to estradiol and bacteria in the laboratory and expression patterns of hepcidin and iNOS in fish from Shenandoah, Potomac, and out-of-basin rivers? 3. Use LMB microarrays to identify candidate gene expression biomarkers for exposure of large and smallmouth bass to estrogen and other endocrine-disrupting compounds identified in companion studies. HYPHOTHESIS TO BE TESTED Estrogen or EDCs, which may cause intersex in smallmouth bass, disrupt expression of genes involved in innate immunity, in particular hepcidin or iNOS, thus increasing susceptibility of smallmouth bass to bacterial infection.
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