da Silva Patricia Mirella, Hégaret Hélène, Lambert Christophe, Wikfors Gary H, Le Goïc Nelly, Shumway Sandra E, Soudant Philippe
Université de Bretagne Occidentale-IUEM, LEMAR CNRS UMR 6539, Place Nicolas Copernic, Technopôle Brest Iroise, 29280 Plouzané, France.
Toxicon. 2008 Mar 15;51(4):563-73. doi: 10.1016/j.toxicon.2007.11.006. Epub 2007 Nov 21.
The present study evaluated the possible effects of a toxic dinoflagellate, Karenia selliformis, upon immunological hemocyte functions of the Manila clam Ruditapes philippinarum, and on the progression of infection by Perkinsus olseni. Clams with variable levels of perkinsosis were exposed for 6 weeks to simulated blooms of cultured the K. selliformis (10(2) and 10(3)cell ml(-1)). Samples were collected after 0, 2, 3, and 6 weeks of exposure. The following hemocyte parameters were measured by flow cytometry: percentage of dead cells, cell size and complexity, apoptosis, phagocytosis, and production of reactive oxygen species. Agglutination activities of K. selliformis on horse erythrocytes, serum protein concentration, and condition index of clams were also assessed. The harmful alga K. selliformis caused a significant decrease in hemocyte size and percentage of apoptotic cells. In contrast, P. olseni did not affect clams strongly; the only significant effect was an increase in hemocyte size in heavily infected clams. After 2 and 3 weeks, the prevalence and burden of P. olseni decreased in clams exposed to K. selliformis, but after 6 weeks, and a diminution in K. selliformis cell density in the exposure, this effect disappeared. In vitro tests exposing P. olseni to K. selliformis showed direct algal toxicity to the parasite (increased percentage of dead cells and altered morphology). Initial exposure of P. olseni-infected clams to K. selliformis appeared to modify the host-parasite interaction by causing effects in both organisms.
本研究评估了有毒甲藻梨形环沟藻（Karenia selliformis）对菲律宾蛤仔（Ruditapes philippinarum）免疫血细胞功能以及奥尔森派金虫（Perkinsus olseni）感染进程的可能影响。将患有不同程度派金虫病的蛤仔暴露于模拟的梨形环沟藻藻华环境中6周（藻细胞密度为10²和10³个细胞/毫升）。在暴露0、2、3和6周后采集样本。通过流式细胞术测量以下血细胞参数：死细胞百分比、细胞大小和复杂性、凋亡、吞噬作用以及活性氧的产生。还评估了梨形环沟藻对马红细胞的凝集活性、蛤仔的血清蛋白浓度和状况指数。有害藻类梨形环沟藻导致血细胞大小和凋亡细胞百分比显著降低。相比之下，奥尔森派金虫对蛤仔的影响不强烈；唯一显著的影响是重度感染蛤仔的血细胞大小增加。在暴露2周和3周后，暴露于梨形环沟藻的蛤仔中奥尔森派金虫的患病率和感染负荷降低，但在6周后，随着暴露环境中梨形环沟藻细胞密度的降低，这种影响消失。将奥尔森派金虫暴露于梨形环沟藻的体外试验显示藻类对寄生虫具有直接毒性（死细胞百分比增加且形态改变）。最初将感染奥尔森派金虫的蛤仔暴露于梨形环沟藻似乎通过对两种生物产生影响来改变宿主 - 寄生虫相互作用。
