The major goal of this project is to detect impaired development and reproduction arising from exposure to hazardous substances, singly and as complex mixtures, in water. Once these deleterious effects are detected, fractionation and treatment of samples leading to such change will be performed in a series of toxicant identification exercises. These steps will require bioassay driven chemical analysis to identify the toxic component(s) of complex mixtures. Despite the importance of impaired development, use of this as an endpoint for toxicant identification evaluations will require considerable effort. However, this task is made somewhat easier by the use of a unique vertebrate model, the medaka, a small teleost fish long recognized as a model for developmental biology. In addition, newly developed nanoinjection procedures will be used for precise exposure of embryos to candidate components of toxic complex mixtures. A coordinated, focused effort with a medaka genomic and cDNA library and molecular toolkit using medaka tissues, trout cell lines and tissues will simultaneously concentrate on mechanism(s) of action of compounds proven positive in vivo. Since some of the compounds which will be tested include have been shown to act as endocrine mimics and/or endocrine disruptors, we shall include formation of intersex and interval to sexual maturity as an endpoint. Coordinated morphological and biochemical/molecular studies will address features of proteins necessary for gonadal maturation in control and treated individuals. Agricultural pesticides and herbicides used on highway medians and peripheries will be tested. Because the compounds used for control are changing, we shall devoted effort to analysis of metabolism of newly-emerging compounds, the pyrethroids and acyl ureas. In this phase of the work, we shall focus on creation of a sentinal aquatic organism model useful in detecting exposure and deleterious effect in resident fishes. To achieve the overall goal, three specific aims are proposed. 1) Determine developmental toxicity and reproductive effects of specific compounds in complex mixtures of hazardous wastes using previously calibrated medaka adult breeding pairs and exposure of gametes and embryos; 2) Define, via molecular imaging studies, specific alterations in embryos, larvae, juveniles and sexually mature medaka exhibiting biomarkers of exposure and effect; and, 3) Identify new biomarkers associated with the biochemical and molecular mechanisms of action of compounds including those shown to impair development and/or reproduction.
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