Université Bordeaux, EPOC, UMR 5805, 33120 Arcachon, France.
CNRS, EPOC, UMR 5805, 33120 Arcachon, France.
Fish Shellfish Immunol. 2014 Feb;36(2):510-8. doi: 10.1016/j.fsi.2013.12.009. Epub 2013 Dec 28.
This study assessed the effect of Brown Muscle Disease (BMD) on Manila clam Venerupis philippinarum fitness. BMD was discovered in 2005. It affects the posterior adductor muscle and leads to clam gaping and eventually death. Three statuses of clams were compared: buried individuals with no signs of BMD (BUR); clams at the surface of the sediment with no signs of BMD (SURF) and clams at the surface of the sediment exhibiting signs of brown muscle disease (BMD). Physiological (condition index), immune (hemocyte parameters) and molecular (gene expressions) parameters collected seasonally were analyzed and compared. Results demonstrated a seasonal pattern in condition index (CI) with peaks in spring/summer and decreases in autumn/winter. At each season, the highest CI was observed in BUR and the lowest CI was observed in BMD. In terms of immune response, phagocytosis rate and capacity were higher in clams with BMD whereas the health status of the clams did not influence the total hemocyte count. Genes involved in the immune system (comp, tnf, inter) were upregulated in clams with BMD. The molecular analysis of gill and posterior muscle showed higher mitochondrial metabolism (cox-1, 16S) in cells of infected clams, suggesting a stronger energetic demand by these cells. Finally, genes involved in oxidative stress response (cat, sod), detoxification (mt) and DNA repair (gadd45) were also overexpressed due to reactive oxygen species production. Most of the studied parameters underlined a cause-effect correlation between Manila clam health status (BUR, SUR, BMD) and physiological parameters. An important stress response was observed in BMD-infected clams at different scales, i.e. condition index, immune parameters and stress-related gene expression.
本研究评估了布朗肌肉疾病（BMD）对菲律宾蛤仔（Venerupis philippinarum）健康的影响。BMD 于 2005 年被发现，它影响后闭壳肌，导致蛤仔张开，最终死亡。比较了三种蛤仔的状态：没有 BMD 迹象的埋栖个体（BUR）、沉积物表面没有 BMD 迹象的蛤仔（SURF）和沉积物表面有 BMD 迹象的蛤仔（BMD）。采集了季节性的生理（体质指数）、免疫（血球参数）和分子（基因表达）参数，并进行了分析和比较。结果表明，体质指数（CI）呈季节性模式，春季/夏季峰值，秋季/冬季下降。在每个季节，BUR 的 CI 最高，BMD 的 CI 最低。在免疫反应方面，BMD 蛤仔的吞噬率和吞噬能力较高，而蛤仔的健康状况并不影响总血球计数。参与免疫系统的基因（comp、tnf、inter）在 BMD 蛤仔中上调。鳃和后肌肉的分子分析显示，受感染蛤仔的细胞中线粒体代谢（cox-1、16S）较高，表明这些细胞的能量需求更强。最后，由于活性氧物质的产生，参与氧化应激反应（cat、sod）、解毒（mt）和 DNA 修复（gadd45）的基因也过表达。研究的大多数参数强调了菲律宾蛤仔健康状况（BUR、SUR、BMD）与生理参数之间的因果关系。在 BMD 感染的蛤仔中观察到了一个重要的应激反应，涉及到体质指数、免疫参数和应激相关基因表达等多个层面。
