维氏气单胞菌的smpB、tmRNA及hfq敲除菌株减毒活疫苗筛选

Screening out Live Attenuated Vaccine from Aeromonas veronii Strain without smpB,tmRNA or hfq

为筛选维氏气单胞菌减毒活疫苗,为水产重要细菌性病害的防控提供新策略,本文通过荧光实时定量PCR检测三种敲除型菌株smpB、tmRNA及hfq中毒力相关基因表达;并采取腹腔注射法对尼罗罗非鱼进行野生型及三种敲除型感染,观察染病罗非鱼症状,计算累计死亡率及LD50。结果表明,维氏气单胞菌野生型与三种敲除型菌株相比,细菌毒力相关蛋白表达均呈现显著差异,部分毒力相关基因显著下调;三种敲除型菌株LD50分别增加1.24、5.32和19倍。由此可见,三种敲除型维氏气单胞菌可作为候选减毒疫苗,下调显著的hfq菌株是制备减毒疫苗的首选。

In order to screen out live attenuated vaccines from Aeromonas veronii so as to provide a new strategy for controlling against bacterial diseases of aquatic products,toxic gene expressions of A.veronii strains deleted smpB,tmRNA or hfq were detected by Quantitative Real-time PCR.The symptom,accumulative death rate and LD50 of the wild Oreochromis niloticus and some infected with deleted strains by Intraperitoneal injection were recorded or calculated.The resulted showed there were significant differences among bacterial toxicity relative protein expressions of three deleted strains and wild A.veronii,some of them obviously went down,LD50 of three strains added up to 1.24,5.32 and 19 times,respectively.Therefore the deleted A.veronii strains could be developed for candidates of attenuated vaccines,hfq strain was a first choice.