DISTAV, Dipartimento di Scienze della Terra, dell'Ambiente e della Vita, Università di Genova, Corso Europa 26, 16132 Genova, Italy.
Fish Shellfish Immunol. 2013 Dec;35(6):1906-15. doi: 10.1016/j.fsi.2013.09.027. Epub 2013 Sep 27.
Marine bivalves can accumulate large numbers of bacteria, in particular Vibrio species, whose persistence in bivalve tissues largely depends on their sensitivity to the bactericidal activity of circulating hemocytes and hemolymph soluble factors. The interactions between vibrios and hemolymph have been investigated, in particular in bivalve species susceptible to infection by certain Vibrio spp. and strains. In this work, the effects of two bivalve pathogens, Vibrio splendidus LGP32 (V.s.) and Vibrio aestuarianus 01/032 (V.a.), isolated from oyster mortality outbreaks, on the hemocytes of Mytilus galloprovincialis were investigated. In vitro, V.s., but not V.a., induced a dramatic decrease in lysosomal membrane stability-LMS in the hemocytes; both vibrios induced a moderate lysozyme release, with V.s. > V.a.. The V.s.-induced decrease in LMS was mediated by activation of PI-3Kinase, as shown by use of different kinase inhibitors. TEM analysis showed rapid internalization of both vibrios; however, V.s. lead to cellular and lysosomal damage and was able to survive within the hemocytes, whereas significant killing of V.a. was observed. In vivo, in mussels challenged with either vibrio and sampled at 6, 24 and 96 h post-injection, transient decreases in hemocyte LMS and progressive increases in serum lysozyme activity were observed, with V.s. > V.a.. Moreover, whereas V.a. was efficiently cleared from hemolymph, V.s. showed significant growth, that was maximal at 24 h p.i. when lowest LMS values were recorded in the hemocytes. Both vibrios also induced significant decreases in LMS in the digestive gland, again with V.s. > V.a.. The results indicate distinct interactions between mussel hemocytes and the two vibrio strains tested. The effects of V.s. may be due to the capacity of this strain to interfere with the signaling pathways involved in hemocyte function, thus escaping the bactericidal activity of the host cell, as observed for certain mammalian pathogens. Although V.s. is considered not pathogenic to Mytilus, this vibrio strain can affect the lysosomal function at the cellular and tissue level, thus leading to stressful conditions.
海洋双壳贝类可以积累大量的细菌，特别是弧菌属物种，其在双壳贝类组织中的持久性在很大程度上取决于它们对循环血细胞和血淋巴可溶性因子杀菌活性的敏感性。已经研究了弧菌与血淋巴之间的相互作用，特别是在易受某些弧菌属物种和菌株感染的双壳贝类物种中。在这项工作中，研究了两种贝类病原体，即来自牡蛎死亡爆发的灿烂弧菌 LGP32（V.s.）和港湾弧菌 01/032（V.a.），对贻贝血细胞的影响。在体外，V.s.，而不是 V.a.，导致血细胞中的溶酶体膜稳定性-LMS 急剧下降；两种弧菌都诱导中度溶菌酶释放，V.s.>V.a.。V.s.诱导的 LMS 下降是通过激活 PI-3Kinase 介导的，如使用不同的激酶抑制剂所示。TEM 分析显示两种弧菌都迅速内化；然而，V.s.导致细胞和溶酶体损伤，并能够在血细胞内存活，而 V.a.则被大量杀死。在体内，用两种弧菌攻击贻贝，并在注射后 6、24 和 96 小时取样，观察到血细胞 LMS 短暂下降和血清溶菌酶活性逐渐增加，V.s.>V.a.。此外，虽然 V.a.从血淋巴中被有效清除，但 V.s.显示出显著的生长，在 24 小时时最大，此时血细胞中的 LMS 值记录最低。两种弧菌还导致消化腺中 LMS 显著下降，V.s.>V.a.。这些结果表明贻贝血细胞与两种测试的弧菌菌株之间存在明显的相互作用。V.s.的作用可能是由于该菌株能够干扰参与血细胞功能的信号通路，从而逃避宿主细胞的杀菌活性，就像某些哺乳动物病原体一样。尽管 V.s.被认为对贻贝没有致病性，但这种弧菌菌株可以影响细胞和组织水平的溶酶体功能，从而导致应激状态。
