Toxic Substances in the Environment
University of California-Berkeley
University of Florida
This is a collaborative project proposal between Dr. Chris Vulpe of the University of California-Berkeley and individual researcher Dr. Nancy Denslow of the University of Florida. Each research group is focused on understanding the molecular mode of action of Superfund chemicals but use different approaches and model organisms. In this project, each research group is taking advantage of their unique skills and assay systems to interrogate some of the chemicals of interest to the other group. The chemicals cover a wide range of toxicity pathways and include the pesticides methoxychlor, p,p'-DDE, dieldrin, and toxaphene, benzene, trichloroetheylene, and cadmium. The integration of information from the model systems and assays provides a more complete understanding of each chemical. The key assays that are being used in this project include parallel deletion analysis (PDA) in yeast and microarray analysis of subchronic toxican exposure in largemouth bass. The PDA assay relies on a yeast library made up of a set of deletion strains for each yeast gene. After exposure only yeast strains with a deleted susceptibility gene survive the exposure and these can be identified by parallel processing on a special DNA microarray. The largemouth bass assay is being used to determine the effects of subchronic exposures of environmentally relevant doses of chemicals via the diet and the effects on toxicity pathways in the liver and the gonad. The research is based on three specific aims:
- To use parallel deletion analysis in yeast to identify candidate susceptibility genes in humans and fish,
- Develop biomarkers of exposure in subchronic administration of chemicals to largemouth bass, and
- Integrating gene expression and functional data to provide insight of toxicity pathways.
The overall hypothesis that the researchers are testing is that Superfund chemicals target similar toxicity pathways in yeast and fish and that these identify likely candidates of susceptibility in humans.