R8 PM Pesticide Mixtures
Thursday, 17 November 2005: 1:50 PM - 5:30 PM in 331-332

(BIA-1117-747693) Characterization of tissue specific protein and gene expression changes in response to binary mixtures of pesticides.

Biales, A¹, Bencic, D¹, Lazorchak, J¹, Flick, R¹, Lattier, D¹, ¹ USEPA/ORD/NERL/EERD/MIRB, Cincinnati, OH, USA

ABSTRACT- Aquatic organisms and other receptors in the Nation's watersheds are exposed to complex environmental mixtures of natural and synthetic origins. Components of these mixtures vary based on their ecological context. Efforts have focused on establishing relatively quick, sensitive biological methods that are capable of distinguishing mixture constituents; however, little progress has been made. Here we use 2-Dimensional (2-D) protein gel electrophoresis to identify changes in protein abundance in adult and juvenile fathead minnows (Pimephales promelas) exposed to a binary mixture of ecologically related chemical pesticides at environmentally relevant concentrations. Because expressed proteins are directly responsible for mediating cellular responses, changes in their abundance are considered to have more biological relevance and have been shown to be less variable among individuals than transcriptional profiles. Chemicals were selected because they are commonly used in agricultural settings throughout the United States and are therefore likely to co-occur in aquatic ecosystems. We first characterized the differential protein responses to these chemicals individually in five tissues known to be commonly involved in toxicological pathways: liver, gill, kidney, brain and gonads and responsive proteins were identified by mass spectrometry. Following characterization of the individual chemicals, protein expression responses of binary mixtures were analyzed in the same five tissues using 2-D protein gel electrophoresis. In the next phase of this study we will synthesize QPCR oligonucleotide primers against amino acid sequences for responsive proteins. These QPCR primers will then be used to correlate changes in transcription of individual genes with abundance changes in associated proteins, in order to create useful transcription-based indicators of both individual and mixture specific exposures. This will be among the first projects to measure global biological changes as a response to the complex interactions of mixture components.′

Key words: Protein, Gene expression, Mixtures, Pesticides