title: Effect of Nitrate, Ammonium and Urea on Growth and Pinnatoxin G Production of Vulcanodinium rugosum.
abstract: Vulcanodinium rugosum, a recently described dinoflagellate species producing a potent neurotoxin (pinnatoxin G), has been identified in French Mediterranean lagoons and was responsible for recurrent episodes of shellfish toxicity detected by mouse bioassay. Until now, the biology and physiology of V. rugosum have not been fully investigated. We studied the growth characteristics and toxicity of a V. rugosum strain (IFR-VRU-01), isolated in the Ingril lagoon in June 2009 (North-Western French Mediterranean Sea). It was cultivated in Enriched Natural Sea Water (ENSW) with organic (urea) and inorganic (ammonium and nitrate) nitrogen, at a temperature of 25 °C and irradiance of 100 μmol/m²·s(-1). Results showed that ammonium was assimilated by cells more rapidly than nitrate and urea. V. rugosum is thus an osmotrophic species using urea. Consequently, this nitrogen form could contribute to the growth of this dinoflagellate species in the natural environment. There was no significant difference (Anova, p = 0.856) between the growth rate of V. rugosum cultivated with ammonium (0.28 ± 0.11 day(-1)), urea (0.26 ± 0.08 day(-1)) and nitrate (0.24 ± 0.01 day(-1)). However, the production of chlorophyll a and pinnatoxin G was significantly lower with urea as a nitrogen source (Anova, p < 0.027), suggesting that nutritional conditions prevailing at the moment of the bloom could determine the cellular toxicity of V. rugosum and therefore the toxicity measured in contaminated mollusks. The relatively low growth rate (≤0.28 day(-1)) and the capacity of this species to continuously produce temporary cysts could explain why cell densities of this species in the water column are typically low (≤20,000 cells/L).
authors.affiliation: Laboratoire Environnement Ressources du Languedoc Roussillon, Center for Marine Biodiversity, Exploitation and Conservation (MARBEC), Ifremer, Sète Cedex 3 CS30171, France. eric.abadie@ifremer.fr.
authors.forename: Eric
authors.initials: E
authors.lastname: Abadie
authors.affiliation: Laboratoire Environnement Ressources du Languedoc Roussillon, Center for Marine Biodiversity, Exploitation and Conservation (MARBEC), Ifremer, Sète Cedex 3 CS30171, France. kaci_lamia@hotmail.fr.
authors.forename: Lamia
authors.initials: L
authors.lastname: Kaci
authors.affiliation: Laboratoire Environnement Ressources du Languedoc Roussillon, Center for Marine Biodiversity, Exploitation and Conservation (MARBEC), Ifremer, Sète Cedex 3 CS30171, France. tom.berteaux@ifremer.fr.
authors.forename: Tom
authors.initials: T
authors.lastname: Berteaux
authors.affiliation: ODE/UL/PHYC, Ifremer, Rue de l'Ile d'Yeu, Nantes Cedex 3 BP 21105 44311, France. philipp.hess@ifremer.fr.
authors.forename: Philipp
authors.initials: P
authors.lastname: Hess
authors.affiliation: ODE/UL/PHYC, Ifremer, Rue de l'Ile d'Yeu, Nantes Cedex 3 BP 21105 44311, France. veronique.sechet@ifremer.fr.
authors.forename: Véronique
authors.initials: V
authors.lastname: Sechet
authors.affiliation: Center for Marine Biodiversity, Exploitation and Conservation (MARBEC), Université de Montpellier, CNRS, IRD, Ifremer, Place Eugène Bataillon, CC93, Montpellier Cedex 5 34095, France. estelle.masseret@univ-montp2.fr.
authors.forename: Estelle
authors.initials: E
authors.lastname: Masseret
authors.affiliation: UMR 5244, Interaction Hotes Pathogenes Environnement (IHPE), Ifremer, Université de Perpignan, Université de Montpellier, Place Eugène Bataillon, CC80, Montpellier Cedex F-34095, France. jean.luc.rolland@ifremer.fr.
authors.forename: Jean Luc
authors.initials: JL
authors.lastname: Rolland
authors.affiliation: Center for Marine Biodiversity, Exploitation and Conservation (MARBEC), Université de Montpellier, CNRS, IRD, Ifremer, Place Eugène Bataillon, CC93, Montpellier Cedex 5 34095, France. mohamed.laabir@univ-montp2.fr.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Laabir
mesh_terms: D000470:Alkaloids / Q000096:biosynthesis*; D064751:Ammonium Compounds / Q000494:pharmacology*; D002734:Chlorophyll; D000077194:Chlorophyll A; D004141:Dinoflagellida / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D009566:Nitrates / Q000494:pharmacology*; D013141:Spiro Compounds; D014508:Urea / Q000494:pharmacology*
chemical_list: D000470:Alkaloids; D064751:Ammonium Compounds; D009566:Nitrates; D013141:Spiro Compounds; C552840:pinnatoxin G; D002734:Chlorophyll; D014508:Urea; D000077194:Chlorophyll A
keywords: Ingril lagoon; Vulcanodinium rugosum; growth; nitrogen source; pinnatoxin G