Becking Thomas, Mrugała Agata, Delaunay Carine, Svoboda Jiří, Raimond Maryline, Viljamaa-Dirks Satu, Petrusek Adam, Grandjean Frédéric, Braquart-Varnier Christine
Laboratoire Ecologie et Biologie des Interactions, Equipe: Ecologie, Evolution, Symbiose, Université de Poitiers, UMR CNRS 7267, 5 rue Albert Turpin, F-86073 Poitiers Cedex 9, France.
Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, Prague 2 CZ-12844, Czech Republic.
J Invertebr Pathol. 2015 Nov;132:115-124. doi: 10.1016/j.jip.2015.08.007. Epub 2015 Sep 26.
European crayfish are sensitive to the crayfish plague pathogen, Aphanomyces astaci, carried by North American crayfish species due to their less effective immune defence mechanisms against this disease. During a controlled infection experiment with a susceptible crayfish species Astacus astacus using three A. astaci strains (representing genotype groups A, B, and E), we investigated variation in their virulence and in crayfish immune defence indicators (haemocyte density, phenoloxidase activity, and production of reactive oxygen species). Experimental crayfish were exposed to two dosages of A. astaci spores (1 and 10 spores mL(-1)). The intensity and timing of the immune response differed between the strains as well as between the spore concentrations. Stronger and faster change in each immune parameter was observed in crayfish infected with two more virulent strains, indicating a relationship between crayfish immune response and A. astaci virulence. Similarly, the immune response was stronger and was observed earlier for the higher spore concentration. For the first time, the virulence of a strain of the genotype group E (isolated from Orconectes limosus) was experimentally tested. Total mortality was reached after 10 days for the two higher spore dosages (10 and 100 spores mL(-1)), and after 16 days for the lowest (1 spore mL(-1)), revealing equally high and rapid mortality as caused by the genotype group B (from Pacifastacus leniusculus). No mortality occurred after infection with genotype group A during 60 days of the experimental trial.
欧洲螯虾对北美螯虾物种携带的螯虾瘟疫病原体——螯虾疫霉（Aphanomyces astaci）敏感，因为它们对这种疾病的免疫防御机制效果较差。在一项针对易感螯虾物种欧洲螯虾（Astacus astacus）的对照感染实验中，我们使用了三种螯虾疫霉菌株（代表基因型组A、B和E），研究了它们的毒力以及螯虾免疫防御指标（血细胞密度、酚氧化酶活性和活性氧产生）的变化。实验螯虾暴露于两种剂量的螯虾疫霉孢子（1和10个孢子 mL⁻¹）。免疫反应的强度和时间在菌株之间以及孢子浓度之间存在差异。在感染了两种毒性更强菌株的螯虾中，每个免疫参数都观察到更强、更快的变化，这表明螯虾免疫反应与螯虾疫霉毒力之间存在关联。同样，对于较高的孢子浓度，免疫反应更强且出现得更早。首次对基因型组E的一个菌株（从美国螯虾（Orconectes limosus）分离）的毒力进行了实验测试。对于两种较高的孢子剂量（10和100个孢子 mL⁻¹），10天后达到总死亡率，对于最低剂量（1个孢子 mL⁻¹），16天后达到总死亡率，显示出与基因型组B（从加州信号螯虾（Pacifastacus leniusculus）分离）导致的同样高且快速的死亡率。在实验试验的60天内，感染基因型组A后未出现死亡。
