Gene transcription profiling in mussels (Mytilus sp.) exposed to the model compounds copper choloride and Benzo[a]pyrene

anglais. Norsk Institutt for Vannforskning (NIVA)

anglais. AbstractEnvironmental pollution is increasing in coastal areas and is responsible for adversehealth effects in marine wild life. The oceans are vast and the sources of pollution aremany, which make the effects of pollution difficult to assess in a reliable and validway. Different toxic components have different mode of actions, leading to series ofresponses in organism. The first early responses to a toxicant, in most cases a systemat the molecular level designed to target the specific toxicant, is important to identify.A series of biological marker (biomarker) analyses have thus been developed toassess the effects of exposure to single chemicals (metals and organic compounds)and complex pollution discharges. Single biomarkers are useful as indicators of thepresence pollution as they reflect biochemical and physiological changes, but theymay not necessary predict the effects on the whole organism. Several mussel speciesin the genus Mytilus has frequently been used to assess chemical pollution in theaquatic environment and with the availability of high-content molecular methods suchas microarrays, makes this group of species highly interesting for use in toxicityassessment and environmental monitoring. The aim of this project was to evaluate theperformance of a newly developed high-content Mytilus sp. oligonucleotide array(oligoarray) and to specifically assess the transcriptional effects in M. edulis digestiveorgan after exposure to the fundamentally different pollutants Copper chloride(CuCl2) and the Polycyclic Aromatic Hydrocarbon (PAH) Benzo[a]pyrene (BaP).The results showed that an oligoarray based on M. edilus and M. galloprovincialescould be used to study the differential expression in M. edulis digestive gland afterexposure to Cu and BaP. There were also indentified different MoA for Cu and BaP,as well as several genes and pathways related to general stress responses of toxicityfor both compounds. Further work on the development of the array includes inclusionof additional sequence information from other sequencing projects, redundancyreduction and further verification of the microarray results by Real Time quantitativePolymerase Chain Reaction (RT-qPCR) to assess the dynamic range and sequencespecificity of the array.Keywords: Pollution, Environmental monitoring, biomarkers, common mussel(Mytilus sp.), BaP, Cu, microarray, gene expression.