Proteins in ecotoxicology - how, why and why not?

The growing interest in the application of proteomic technologies to solve toxicology issues and its relevance in ecotoxicology research has resulted in the emergence of "ecotoxicoproteomics". There is a general consensus that ecotoxicoproteomics is a powerful tool to spot early molecular events involved in toxicant responses, which are responsible for the adverse effects observed at higher levels of biological organization, thus contributing to elucidate the mode of action of stressors and to identify specific biomarkers. Ultimately, early-warning indicators can then be developed and deployed in "in situ" bioassays and in environmental risk assessment. The number of field experiments or laboratory trials using ecologically relevant test-species and involving proteomics has been, until recently, insufficient to allow a critical analysis of the real benefits of the application of this approach to ecotoxicology. This article intends to present an overview on the applications of proteomics in the context of ecotoxicology, focusing mainly on the prospective research to be done in invertebrates. Although these represent around 95% of all animal species and in spite of the key structural and functional roles they play in ecosystems, proteomic research in invertebrates is still in an incipient stage. We will review applications of ecotoxicoproteomics by evaluating the technical methods employed, the organisms and the contexts studied, the advances achieved until now and lastly the limitations yet to overcome will be discussed.