title: Immunological and physiological responses of the periwinkle Littorina littorea during and after exposure to the toxic dinoflagellate Alexandrium minutum.
abstract: Species of the dinoflagellate genus Alexandrium produce phycotoxins responsible for paralytic shellfish poisoning. Blooms of Alexandrium minutum reach very high concentrations of vegetative cells in the water column; and when these blooms occur, large numbers of toxic cysts can be produced and deposited on sediments becoming available to benthic species. The present study investigated the potential effect of exposure to toxic cysts of A. minutum on the periwinkle Littorinalittorea. Snails were exposed for nine days to pellicle cysts of toxic and non-toxic dinoflagellates, A. minutum and Heterocapsa triquetra, respectively, followed by six days of depuration while they were fed only H. triquetra. Toxin accumulation, condition index, immune and histopathological responses were analyzed. Histological alterations were also monitored in snails exposed to a harmful A. minutum bloom, which naturally occurred in the Bay of Brest. Snails exposed to toxic cysts showed abnormal behavior that seems to be toxin-induced and possibly related to muscle paralysis. Periwinkles accumulated toxins by preying on toxic cysts and accumulation appeared dependent on the time of exposure, increasing during intoxication period but tending to stabilize during depuration period. Toxic exposure also seemed to negatively affect hemocyte viability and functions, as ROS production and phagocytosis. Histological analyses revealed that toxic exposure induced damages on digestive organs of snails, both in laboratory and natural systems. This study demonstrates that an exposure to the toxic dinoflagellate A. minutum leads to sublethal effects on L. littorea, which may alter individual fitness and increase the susceptibility of snails to pathogens and diseases.
authors.affiliation: Programa de Pós-Graduação em Ecologia, Departamento de Ecologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: neves.raf@hotmail.com.
authors.forename: Raquel A F
authors.initials: RA
authors.lastname: Neves
authors.affiliation: Laboratório de Ecologia Trófica, Departamento de Biologia Marinha, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: gmandali@biologia.ufrj.br.
authors.forename: Gisela M
authors.initials: GM
authors.lastname: Figueiredo
authors.affiliation: Programa de Pós-Graduação em Ecologia, Departamento de Ecologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Laboratório de Zooplâncton Marinho, Departamento de Biologia Marinha, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: jlv@biologia.ufrj.br.
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Valentin
authors.affiliation: Laboratório de Imunologia e Patologia de Invertebrados, Departamento de Biologia Molecular, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, Paraíba, Brazil. Electronic address: mirella_dasilva@hotmail.com.
authors.forename: Patricia Mirella
authors.initials: PM
authors.lastname: da Silva Scardua
authors.affiliation: Laboratoire des Sciences de l'Environnement Marin, UMR 6539 CNRS/UBO/IRD/IFREMER, Institut Universitaire Européen de la Mer, 29280 Plouzané, France; GDR 3569 'PHYCOTOX, Des Microalgues aux Risques pour l'Homme et l'Ecosystème', 29280 Plouzané, France. Electronic address: helene.hegaret@univ-brest.fr.
authors.forename: Hélène
authors.initials: H
authors.lastname: Hégaret
mesh_terms: D000818:Animals; D004141:Dinoflagellida / Q000737:chemistry*; D049851:Gastropoda / Q000187:drug effects* / Q000276:immunology / Q000502:physiology; D006434:Hemocytes / Q000187:drug effects; D008387:Marine Toxins / Q000378:metabolism / Q000633:toxicity*; D010587:Phagocytosis / Q000187:drug effects
chemical_list: D008387:Marine Toxins
keywords: Alexandrium; Gastropod; Harmful algal bloom (HAB); Hemocytes; Histopathology; Toxin accumulation