FN Archimer Export Format PT J TI The toxic dinoflagellate Alexandrium minutum affects oyster gamete health and fertilization potential BT AF Castrec, Justine Fabioux, Caroline Le Goïc, Nelly Boulais, Myrina Soudant, Philippe Hégaret, Helene AS 1:3;2:3;3:2;4:1;5:2;6:2; FF 1:;2:;3:;4:PDG-RBE-PFOM-PI;5:;6:; C1 LEMAR UMR 6539 CNRS/UBO/IRD/Ifremer, IUEM, rue Dumont d’Urville, 29280, Plouzané, France LEMAR UMR 6539 CNRS/UBO/IRD/Ifremer, IUEM, rue Dumont d’Urville, 29280, Plouzané, France LEMAR UMR 6539 CNRS/UBO/IRD/Ifremer, IUEM, rue Dumont d’Urville, 29280, Plouzané, France C2 IFREMER, FRANCE CNRS, FRANCE UBO, FRANCE SI BREST SE PDG-RBE-PFOM-PI UM LEMAR IN WOS Ifremer UMR WOS Cotutelle UMR copubli-france copubli-univ-france IF 3.737 TC 6 UR https://archimer.ifremer.fr/doc/00701/81322/85687.pdf LA English DT Article DE ;Algal blooms;Algal toxins;Fertilization;Paralytic shellfish toxins (PST);Bioactive extracellular compounds (BEC);Spermatozoa;Oocyte;Flow cytometry;(=Magallana) gigas;Bivalves AB Dinoflagellates from the globally distributed genus Alexandrium are known to produce both paralytic shellfish toxins (PST) and uncharacterized bioactive extracellular compounds (BEC) with allelopathic, ichthyotoxic, hemolytic and cytotoxic activities. In France, blooms of Alexandrium minutum appear generally during the spawning period of most bivalves. These blooms could therefore alter gametes and/or larval development of bivalves, causing severe issues for ecologically and economically important species, such as the Pacific oyster Crassostrea (=Magallana) gigas. The aim of this work was to test the effects of three strains of A. minutum producing either only PST, only BEC, or both PST and BEC upon oyster gametes, and potential consequences on fertilization success. Oocytes and spermatozoa were exposed in vitro for 2 hours to a range of environmentally realistic A. minutum concentrations (10 to 2.5 × 104 cells mL-1). Following exposure, gamete viability and reactive oxygen species (ROS) production were assessed by flow cytometry, spermatozoa motility and fertilization capacities of both spermatozoa and oocytes were analysed by microscopy. Viability and fertilization capacity of spermatozoa and oocytes were drastically reduced following exposure to 2.5 × 104 cells mL-1 of A. minutum. The BEC-producing strain was the most potent strain decreasing spermatozoa motility, increasing ROS production of oocytes, and decreasing fertilization, from the concentration of 2.5 × 103 cells mL-1. This study highlights the significant cellular toxicity of the BEC produced by A. minutum on oyster gametes. Physical contact between gametes and motile thecate A. minutum cells may also contribute to alter oyster gamete integrity. These results suggest that oyster gametes exposure to A. minutum blooms could affect oyster fertility and reproduction success. PY 2021 PD JUN SO Marine Environmental Research SN 0141-1136 PU Elsevier BV VL 169 UT 000672848900002 DI 10.1016/j.marenvres.2021.105401 ID 81322 ER EF