转座子mini-Tn10介导的运动突变对溶藻弧菌毒力的影响

采用转座子mini-Tn10/Km构建了致病性溶藻弧菌的突变库,采用半固体双层平板初筛到73株运动缺陷突变株,初筛的突变株纯化及重复筛选后获得运动性缺陷表型稳定的突变株ND-01MM,Southern鉴定确定其为单位点插入。野生型菌株ND-01和运动缺陷突变株ND-01MM对致病性溶藻弧菌的天然宿主大黄鱼粘液的趋化、粘附以及在大黄鱼吞噬细胞内存活能力等生理功能的比较研究发现,溶藻弧菌运动缺陷后趋化及粘附能力均极显著下降(P<0.01),但在吞噬细胞内的存活能力则与野生型菌株差异不显著(P>0.05)。采用腹腔注射和浸泡两种方式感染大黄鱼,结果发现运动缺陷对浸泡感染的影响较为明显,但对腹腔注射的感染方式影响不大。

Effect of transposon-induced motility defect on virulence of Vibrio alginolyticus

Motility is thought to contribute to the virulence of many pathogenic bacteria. Infection studies in many motile pathogens found that in many causes normal motility was required for efficient infection. However, there are few reports on the direct correlation between motility and virulence in Vibrio. In order to understand the role of motility of Vibrio alginolyticus in virulence, the mini-Tn10/Km transposon-induced mutant bank was constructed and 73 motility defective mutants were screened out by double semi-soft agar medium. After purification and repeated screening the mutant ND-01MM with stable motility defect was obtained and identified by Southern blot. The chemotaxis and adhesion of wild-type strain ND-01 and the mutant ND-01MM to mucus of the natural host Pseudosciaena crocea and their persistence in phagocytes of P. crocea were tested. The results showed that the chemotaxis and adhesion of the mutant was highly significantly impaired(P<0.01)when compared with the wild-type strain, however there was no significant difference in their ability of persistence in phagocytes(P>0.05). The results of infection test showed that the virulence of the mutant was decreased by immersion infection, but not different from the wild-type strain by intraperitoneal injection.