Ifremer, Laboratoire de Génétique et Pathologie, Ave. Mus de Loup, Ronce-Les-Bains, 17390 La Tremblade, France.
J Invertebr Pathol. 2011 Feb;106(2):179-91. doi: 10.1016/j.jip.2010.09.003. Epub 2010 Sep 15.
Several Vibrio species are known to be pathogenic to the Pacific oyster Crassostrea gigas. Survival varies according to pathogen exposure and high mortality events usually occur in summer during gametogenesis. In order to study the effects of gametogenetic status and ploidy (a factor known to affect reproduction allocation in oysters) on vibriosis survival, we conducted two successive experiments. Our results demonstrate that a common bath challenge with pathogenic Vibrio splendidus and Vibrio aestuarianus on a mixture of mature, spawning and non-mature oysters can lead to significant mortality. Previous bath challenges, which were done using only non-mature oysters, had not produced mortality. Immunohistochemical analyses showed the affinity of Vibrio for gonadic tissues, highlighting the importance of sexual maturity for vibriosis infection processes in oysters. Mortality rate results showed poor repeatability between tanks, however, in this bath challenge. We then tested a standardized and repeatable injection protocol using two different doses of the same combination of two Vibrio species on related diploid and triploid oysters at four different times over a year. Statistical analyses of mortality kinetics over a 6-day period after injection revealed that active gametogenesis periods correspond to higher susceptibility to vibriosis and that there is a significant interaction of this seasonal effect with ploidy. However, no significant advantage of triploidy was observed. Triploid oysters even showed lower survival than diploid counterparts in winter. Results are discussed in relation to differing energy allocation patterns between diploid and triploid Pacific oysters.
已知有几种弧菌属物种对太平洋牡蛎（Crassostrea gigas）具有致病性。存活率取决于病原体暴露的情况，并且通常在夏季配子发生期间发生高死亡率事件。为了研究配子发生状态和倍性（已知会影响牡蛎繁殖分配的因素）对弧菌病存活率的影响，我们进行了两项连续的实验。我们的结果表明，用致病性灿烂弧菌（Vibrio splendidus）和港湾弧菌（Vibrio aestuarianus）对成熟、产卵和非成熟牡蛎混合物进行常见的浴式挑战会导致显著的死亡率。之前使用仅非成熟牡蛎进行的浴式挑战并未产生死亡率。免疫组织化学分析显示弧菌对性腺组织的亲和力，突出了性成熟对牡蛎弧菌病感染过程的重要性。然而，在这次浴式挑战中，死亡率结果显示罐间重复性较差。然后，我们使用相同的两种弧菌组合的两种不同剂量，在一年内的四个不同时间，对相关的二倍体和三倍体牡蛎进行了标准化和可重复的注射方案测试。在注射后 6 天的死亡率动力学的统计分析表明，活跃的配子发生期对应更高的弧菌病易感性，并且这种季节性效应与倍性之间存在显著的相互作用。然而，没有观察到三倍体的明显优势。三倍体牡蛎甚至在冬季的存活率低于二倍体牡蛎。结果与二倍体和三倍体太平洋牡蛎之间不同的能量分配模式有关。
