QseBC双组分调控系统对伤寒沙门菌动力的调节作用

Regulation of motility of Salmonella enterica serovar Typhi by QseBC

目的研究伤寒沙门菌Qse BC双组分调控系统对伤寒菌动力的调节作用。方法比较伤寒沙门菌野生株(WT)、qse B缺陷株(Δqse B)和qse C缺陷株(Δqse C)动力差异,选取主要鞭毛基因flh D进行实时定量RT-PCR检测,同时检测qse B的表达水平;构建qse B高表达株,比较其与空载体对照株动力和flh D表达差异。结果与WT相比,Δqse B动力无变化,Δqse C动力减弱;在Δqse C中,flh D表达量下调至约1/4而qse B表达上调;qse B高表达株动力较WT减弱,flh D表达下调。结论 qse BC双组分调控系统能调节伤寒菌动力和主要鞭毛基因flh D的表达;qse B高表达时可抑制细菌动力。

Objective To study the impact of QseBC on the motility of Salmonella enterica serovar Typhi （ S.Typhi ） . Methods The motility of wild-type （ WT） and null mutants （ΔqseB and ΔqseC） at mid-log phase was investigated by swimming assay.Quantitative RT-PCR was carried out to calculate the transcriptional variation of flhD and qseB among WT,ΔqseB andΔqseC.QseB overexpressing strain was constructed to compare its motility and flhD expression with the wild-type control.Results The result of motility assay showed that the motility of ΔqseB was similar to that of the WT strain , while the motility of ΔqseC was much lower than that of WT .qRT-PCR revealed that compared with WT , the expression of flhD was significantly decreased in ΔqseC while the expression of qseB was increased considerably .The motility of QseB overex-pressing strain was lower .Conclusion The expression of flhD may be regulated by QseBC which has an effect on the motil-ity of S.typhi, and the overexpression of QseB may inhibit the motility .