YibT介导鼠伤寒沙门氏菌生物膜形成的分子机制研究

Molecular Regulatory Mechanism of Biofilm Formation of Salmonella Mediated by Protein yibT

为了研究yibT基因在鼠伤寒沙门氏菌增殖过程中的作用及分子调控机制,采用基因工程方法提取沙门氏菌的RNA,反转录成cDNA,然后利用实时荧光定量PCR技术(RT-qPCR)检测WT、WTΔyibT、WTΔyibT/pyibT的lptA-G和Lpt转运蛋白及csgD、rpoS的信使核糖核酸(mRNA)表达水平,研究yibT基因对沙门氏菌生物膜形成的影响。结果表明,yibT基因缺失后,可不同程度致使转运蛋白lptA-G的mRNA表达水平下调(P<0.05),其中lptB下调最为显著(P<0.01);yibT缺失可导致csgD表达量(P<0.05)和rpoS表达量显著下调(P<0.01);当yibT回补过表达后可致csgD、rpoS的mRNA表达水平均有不同程度的上调(P<0.05);同时,yibT基因的缺失可导致yecF和uspB的mRNA表达水平均不同程度的下降(P<0.05)。因此,推测yibT基因可能通过参与介导脂多糖的转运与合成来影响鼠伤寒沙门氏菌的生物膜形成,其可能是一种全局转录调控因子或DNA聚合酶,通过影响菌体DNA的复制而调控鼠伤寒沙门氏菌的多个生物学过程。

In order to investigate the effect of protein YibT on the biofilm formation of Salmonella typhimurium,the RNA of Salmonella typhimurium was extracted by genetic engineering method and then reversely transcripted into cDNA.Then real-time quantitative PCR was used to detect the LptA-G and LPT transporters of WT,WTΔyibT,WTΔyibT/pyibT,as well as the mRNA expression levels of csgD and rpoS,to study the regulatory mechanism of yibT on Salmonella biofilm formation.The results showed that the mRNA expression level of transporter LptA-G was down-regulated in different degrees after the deletion of yibT gene(P<0.05),and LptB was down-regulated most significantly(P<0.01).The expressions of csgD(P<0.05)and rpoS(P<0.01)were significantly down-regulated owing to the absence of yibT.When yibT was overexpressed,both csgD and rpoS were up-regulated to varying degrees(P<0.05).Meanwhile,the deletion of yibT gene could decrease the mRNA expression levels of yecF and uspB in different degrees(P<0.05).Therefore,we hypothesized that yibT may affect the biofilm formation of Salmonella typhimurium by participating in the transport and synthesis of lipopolysaccharide.YibT may be a global transcription regulator or DNA polymerase,which regulates a variety of biological processes of Salmonella typhimurium by affecting the replication of bacterial DNA.