宿主整合因子对伤寒沙门菌动力的影响

目的: 探究宿主整合因子(integration host factor,IHF)对伤寒沙门菌动力的影响及其潜在机制。方法: 选用IHF两个亚基HimA和HimD的基因缺失株(△himA pBAD、△himD-pBAD）,并构建相应回补株(himA-C、himD-C),进行细菌动力实验,观察himA和himD对伤寒沙门菌动力的影响。通过实时荧光定量PCR比较野生株(WT-pBAD)与△himA-pBAD、野生株与△himD-pBAD中鞭毛相关基因flhD、fliA和fljB等mRNA表达差异,分析IHF对鞭毛基因的调控作用。结果： 与WT-pBAD相比,△himA-pBAD和△himD pBAD动力均明显减弱(P均<0.05),himA-C、himD-C动力则基本一致。与WT pBAD相比,△himA pBAD、△himD-pBAD中鞭毛相关基因flhD、fliA和fljB的mRNA表达均显著降低(P<0.01或<0.05)。结论： IHF可能通过正向调节鞭毛相关基因flhD、fliA和fljB等转录,增强伤寒沙门菌的动力。

Effect of integration host factor on the motility of Salmonella enterica serovar Typhi

Objective: To investigate the effect of integration host factor (IHF) on the motility of Salmonella enterica serovar Typhi and its potential mechanism. Methods: △himA-pBAD and △himD-pBAD, the mutations of the two subunits of IHF, were selected to construct relative gene complementary strains (himA C and himD-C). Motility assays were used to evaluate the effects of himA and himD on the motility of S. Typhi. Furthermore, quantitative real time PCR was applied to analyze the mRNA levels of flhD, fliA and fljB among WT-pBAD, △himA-pBAD and △himD-pBAD. Results: Compared with WT pBAD, the motilities of both △himA-pBAD and △himD-pBAD were significantly weaker(P<0.05), while himA-C and himD-C did not cause any change in the motilities. In addition, the mRNA levels of flhD, fliA and fljB in △himA-pBAD and △himD-pBAD were also greatly lower than those in WT pBAD (P<0.01 or <0.05). Conclusion: IHF may promote the motility of S. Typhi through activating the transcriptions of flhD, fliA and fljB.