title: Immune responses of phenoloxidase and superoxide dismutase in the manila clam Venerupis philippinarum challenged with Vibrio tapetis--part II: combined effect of temperature and two V. tapetis strains.
abstract: Manila clams, Venerupis philippinarum (Adams and Reeve, 1850), were experimentally infected with two different bacterial strains and challenged with two different temperatures. Bacterial strains used in this study were Vibrio tapetis strain CECT4600(T), the causative agent of Brown Ring Disease (BRD) and V. tapetis strain LP2, supposed less virulent to V. philippinarum. V. tapetis is considered to proliferate at low temperatures, i.e. under 21 °C. In a global warming context we could hypothesize a decrease of mass mortalities caused by V. tapetis but these thermal changes could also directly impact the immune system of the host V. philippinarum. Thus, the aim of this study was to investigate the effects of the extrapallial injection with V. tapetis combined with temperature challenge on two enzymes activities in V. philippinarum. More precisely, after infection, phenoloxidase (PO) and superoxide dismutase (SOD), two major enzymes involved in immune response, were studied for 30 days in two compartments: the mantle and the hemolymph. Conchyolin Deposit Stages (CDS) and Shell Repair Stages (SRS) were also determined 30 days post-injection as a proxy of the virulence of the tested strains. In this study, we highlighted that host-pathogen interaction in a varying environment affects the enzymatic response of the host. The coupled effect of V. tapetis injection and temperature challenge was detected 30 days post injection and resulted in virulence differences. These findings were supported by CDS and SRS determination in clams and lead to the conclusion that clam's immunity could be enhanced at 22 °C while V. tapetis virulence is lowered at this temperature. Another result of our study was the increase of PO and SOD basal activities as clams are exposed to warmer temperature.
authors: UMR 6539 CNRS UBO IRD IFREMER, LEMAR - IUEM - UBO, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Technopôle Brest-Iroise - Rue Dumont d'Urville, 29280 Plouzané, France. Electronic address: gaelle.richard@univ-brest.fr.
authors: Gaëlle
authors: G
authors: Richard
authors: UMR 6539 CNRS UBO IRD IFREMER, LEMAR - IUEM - UBO, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Technopôle Brest-Iroise - Rue Dumont d'Urville, 29280 Plouzané, France.
authors: Cédric
authors: C
authors: Le Bris
authors: UMR 6539 CNRS UBO IRD IFREMER, LEMAR - IUEM - UBO, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Technopôle Brest-Iroise - Rue Dumont d'Urville, 29280 Plouzané, France.
authors: Fabienne
authors: F
authors: Guérard
authors: UMR 6539 CNRS UBO IRD IFREMER, LEMAR - IUEM - UBO, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Technopôle Brest-Iroise - Rue Dumont d'Urville, 29280 Plouzané, France.
authors: Christophe
authors: C
authors: Lambert
authors: UMR 6539 CNRS UBO IRD IFREMER, LEMAR - IUEM - UBO, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Technopôle Brest-Iroise - Rue Dumont d'Urville, 29280 Plouzané, France.
authors: Christine
authors: C
authors: Paillard
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000201:enzymology / Q000276:immunology / Q000382:microbiology; D007113:Immunity, Innate; D014442:Monophenol Monooxygenase / Q000276:immunology*; D013482:Superoxide Dismutase / Q000276:immunology*; D013696:Temperature; D014733:Vibrio / Q000235:genetics / Q000276:immunology / Q000502:physiology*
chemical_list: D014442:Monophenol Monooxygenase; D013482:Superoxide Dismutase
keywords: Phenoloxidase; Superoxide dismutase; Temperature; Venerupis philippinarum; Vibrio tapetis