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(349) A comparison of sublethal responses in developing medaka and salmon embryos to pesticides.
Pincetich, Christopher*,1, Viant, Mark1, Tjeerdema, Ron1, Hinton, David2, 1 UC Davis, Davis, CA, USA2 Duke University, Durham, NC, USA
ABSTRACT- The present situation of persistent xenobiotics in the environment and the associated adverse effects on human health and ecological systems has increased the need for an understanding of their sublethal effects in developing organisms. Unique features of medaka (Oryzias latipes), the transparent chorion and the fact that they live as individual units free from the mother, make these vertebrates particularly useful as subjects for developmental toxicity. The coupling of nuclear magnetic resonance (NMR) spectroscopy and somatic structure data provide precision and detail not obtainable without great time and expense in organisms whose embryo/fetal periods are intra uterine. Chinook salmon (Oncorhynchus tshawytscha) represent an abundant and ecologically important fish species in watersheds draining into the Pacific. This study will determine sub-lethal stress responses in developing medaka and chinook salmon exposed to dinoseb, diazinon, or esfenvalerate during embryogenesis. In vivo 31P NMR Spectroscopy was used to determine the developmental stages at which the energetic biomarkers phosphocreatine and inorganic phosphate are present. Second, embryos were exposed to dinoseb (medaka), or dinoseb, diazinon, and esfenvalerate (salmon) while energetic biomarkers are observed via NMR. Finally, these exposed embryos were preserved for detailed cellular and tissue analysis in order to identify areas of apoptosis, necrosis, cellular differentiation or dedifferentiation. In vivo 31P NMR observations of the entire embryogenesis of medaka resulted in a significant rise in phosphocreatine and a significant drop in phosphomonoester and phosphodiester compounds during organogenesis. In vivo 31P NMR observations of salmon embryos resulted in the detection of phosphocreatine, inorganic phosphate, phosphomonoester and phosphodiester compounds. These studies will not only provide a better understanding of the changes in energetic metabolism of developing fish embryos, but may be a valuable addition to the present knowledge of sublethal responses to pesticide exposures and their implications in human health and vertebrate embryo development.
Key words: NMR spectroscopy, pesticide, medaka, chinook salmon
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