Identifying and Monitoring Environmental Toxicity Using Ceriodaphnia Microarrays

The current U.S. Environmental Protection Agency (EPA) SBIR solicitation states that technology is needed to better identify and monitor sources of pollution and protect water quality. Microarrays may be particularly well suited to identifying environmental toxicity because of their ability to determine both specific and global effects of toxicity. So far, however, microarrays have been employed mainly to identify the mechanisms of toxicity. The aim of this work is to show that Ceriodaphnia dubia microarrays can be a practical technology for identifying, characterizing, and monitoring environmental impact. Specifically, Eon Research hopes to show that microarrays can provide information on the degree of environmental impact and the identity and effects of multiple contaminants in complex mixtures. In Phase I, three reference chemicals (diazinon, chlorphyifos, and copper), whose toxic effects on C. dubia have been well-defined by conventional testing, will be used to generate expression signatures using a 10,000-element spotted cDNA array developed in previous work. Each of these chemicals will be tested individually over a range of concentrations. Eon Research hopes to identify different expression signatures at different levels of toxins corresponding to specific toxicity responses at low dose, and more general stress and cell death responses at higher doses where acute lethality becomes apparent. Additionally, the expression signatures of the binary mixtures of the three chemicals will be examined and compared to the signatures of the individual components. These experiments will help us gauge the difficulty of determining what chemicals are in a mixture based on the mixtures expression signatures. In Phase II, Eon Research will identify expression signatures for a wide range of important environmental contaminants using sequence-defined oligo microarrays. By the end of Phase II, Eon Research will have commercially available environmental contaminants in applications ranging from assessment characterization to monitoring of environmental contaminants and in applications ranging from Toxicity Identification Evaluation (TIE) studies to new chemical registration to Whole Effluent Toxicity (WET) testing.