Environ. Sci. Technol. 2010, 44, 8276–8283
Mediterranean Mussel Gene Expression Profile Induced by Okadaic Acid Exposure CHIARA MANFRIN, RENE’ DREOS,† SILVIA BATTISTELLA, ALFRED BERAN,‡ MARCO GERDOL, LAURA VAROTTO,‡ GEROLAMO LANFRANCHI,| PAOLA VENIER,§ AND ALBERTO PALLAVICINI* Department of Life Sciences, Universita` di Trieste, P.le Valmaura, 9, Trieste, Italy 34148
Received November 19, 2009. Revised manuscript received September 15, 2010. Accepted September 15, 2010.
Seasonal seawater temperature increases define optimal growth conditions for Dinoflagellate species which can reach high concentrations in water column and also in filterfeeding organisms like Mytilus galloprovincialis. Commonly produced by Dinophysis and Prorocentrum spp., okadaic acid (OA) and its analogues are responsible for the Diarrheic Shellfish Poisoning (DSP) syndrome in humans. Closure of shellfishing grounds is therefore recommended by the EU when DSP toxin levels in shellfish exceed 16 µg OA 100 g-1 flesh. Despite not being responsible for casualties either in humans or mussels, DSP outbreaks are considered natural events causing health and economic issues due to the frequency of their occurrence. Since gene expression studies offer a wide range of different solutions, we used a mussel cDNA microarray to evaluate gene expression changes in the digestive gland of mussels fed for five weeks with OA-contaminated nutrient. Among the differentially expressed genes we observed a general up-regulation of transcripts coding for stress proteins, proteins involved in cellular synthesis, and a few not annotated proteins. Overall, at the first time point analyzed we identified 58 candidate transcripts for OA-induced stress in mussels, half of which have unknown function. In this paper we present the first gene expression analysis performed on Mediterranean mussels exposed to okadaic acid. The characterization of these transcripts could be useful for the identification of an early physiological response to OA exposure.
Introduction The Diarrheic Shellfish Poisoning (DSP) syndrome is a serious health issue caused in humans by the ingestion of molluscs contaminated with lipophilic toxins such as okadaic acid (OA) and the structurally related dinophysitoxins 1, 2, and * Corresponding author phone: +39040812237; e-mail: pallavic@ units.it. † Current address: John Innes Centre Norwich Research Park, Colney, Norwich, UK NR47UH. ‡ Current address: Biological Oceanography, National Institute of Oceanography and Experimental Geophysics - OGS, Via A. Piccard 54, Trieste, IT 34010. § Current address: Department of Biology, University of Padova, Via U. Bassi 58/B, Padova, IT 35121. | Current address: CRIBI Biotechnology Centre, University of Padova, Via U. Bassi 58/B, Padova, IT 35121. 8276
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3 (DTX-1, -2, -3). OA production is commonly associated with Dinophysis and Prorocentrum spp. During Dinophysis spp. blooms, usually characterized by population densities of
