Dinoflagellates belonging to the genus Prorocentrum were studied for toxicological and toxin production properties by cell assays and liquid chromatographic methods, using fluorescence and mass-spectrometry detection (LC-FD, LC-MS). Cytotoxicity, characterised by IC50 and morphological changes, was examined. IC50 ranged from 2 ·103 cell equivalents mL-1 for P. cf. faustiae to 133 ·103 for P. rhathymum. Morphological changes such as rounding and membrane blebbing, were observed in fibroblasts exposed to Prorocentrum belizeanum and all Prorocentrum lima from Malaysia, suggesting the presence of okadaic acid (OA). Analytical measurements confirmed the production of OA. However, toxicity not correlated with the presence of OA suggests the production of derivates of OA or others toxins

This project was funded by project ACU-02-005 - INIA / AGL2005-07924-CO4-CO2 2005-2008 - Ministry of Education and Science, Spanish Govern-ment/Centre de Referència en Aqüicultura, DURSI, Generalitat de Catalunya

3 pages, 1 figure, 2 tables.-- The 12th International Conference on Harmful Algae (12th ICHA) took place at DGI-Byen in central, Copenhagen on 4-8 September 2006

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