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

Abstract

The search of early and sensitive biomarkers pointing to toxic effects of contaminants over organisms, has led the state of 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. This may result in virtually impossible application in field ecotoxicological studies and biomonitoring, when native or local species must be used. Molecular biomarkers of toxicity generally show higher sensitivity and precocity in the response, while 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.