【摘要】 文蛤(Meretrixpetechialis)是我国一种重要的海水养殖贝类,其养殖过程中病害导致的规模性死亡时有发生,已有的工作证实致病性弧菌是导致文蛤大规模死亡最为常见的病原。在本研究中,我们通过浸泡感染实验模拟了文蛤在自然条件下的弧菌胁迫环境,明确了攻毒水体中弧菌生长变化规律;攻毒过程中宿主载菌量分析显示,文蛤肝胰腺组织弧菌载量在攻毒后呈第1天急剧上升,第3天迅速下降的变化趋势,而且不同个体间载菌量差异较大;通过不同弧菌含量攻毒实验,发现在攻毒早期文蛤体内弧菌载量与水体环境的弧菌含量之间呈显著的正相关(Spearman’sρ=0.899,P=0.000),而在感染中后期不同攻毒强度组之间无显著差异,且呈现较低水平,为0～205CFU/mg,预示着宿主免疫系统和肝胰腺微生物群落可将致病菌的数量控制在一定的范围。上述研究为开展文蛤感染发病过程中弧菌载量和免疫抗性评价相关研究提供了参考。更多还原

【Abstract】 The clam Meretrix petechialis is an important mollusk cultured in China. Massive deaths frequently occur in the major clam producing areas. Previous research has indicated that several diseases are caused by the genus Vibrio in mollusks, which is also the primary pathogenic bacteria causing deaths in M. petechialis. In the present study, we analyzed the bacterial growth and reproduction in seawater under Vibrio challenge for a period of 24 h. Vibrio immersion experiments were conducted to simulate Vibrio challenge in the natural environment, and we observed that bacterial load in the hepatopancreas of the clam abruptly increased on day 1 and decreased rapidly on day 3 after the challenge, with significant differences in the bacterial load among different clam individuals. In the challenge experiments conducted using different Vibrio doses, a significant positive correlation was observed between the bacterial load and the Vibrio dose in the seawater(Spearman’s ρ = 0.899, P = 0.000) in the initial phase; however, there were no significant differences in the bacterial load among the different groups in the middle–late phases with a lower Vibrio dose of 0–205 CFU/mg. These findings indicate that the host immune system and the microbial community in the host hepatopancreas can regulate the bacterial number to a certain extent. Our results provide a reference for the correlational research of Vibrio load during infection as well as for the evaluation of resistance in the clam M. petechialis.更多还原