Toxicogenomics: new strategies for ecotoxicology studies in autochthonous species I. A glade in the entangled path towards the 'fingerprint' of environmental impact?

The search for early and sensitive biomarkers pointing to toxic effects of contaminants over organisms has led the state-of-the-art to the molecular mechanisms of signalling, target and response. The trial to obtain more specific biomarkers of response to toxicants was, in general, biased by the finding of multiple crosstalks between signalling and the transcription factor regulation on gene expression. Molecular biomarkers of toxicity generally show higher sensitivity and precocity in the response, whereas classical biomarkers such as cholinesterases in organisms exposed to anticholinesterasic agents may show 'inconsistent' responses. The use of non-model aquatic organisms, in general, defies the application of commercially available antibodies and implies the design of primers for gene expression studies from model species sequences. The application of transcriptomics has opened a new way to gene annotation and for the design of adequate molecules as tools for the research in new biomarkers in autochthonous species.