σB因子在单核细胞增生李斯特菌环境应激反应中的调控作用

摘要

为了解σB因子在单核细胞增生李斯特菌(LM)环境应激反应中的调控作用,笔者用基因重叠延伸PCR(SOE-PCR)和同源重组的方法构建了SigmaB基因缺失株,分析该缺失株在不同温度、pH和高盐压力条件下的应激反应能力及应激相关基因的转录水平.结果表明:与野毒株相比,SigmaB基因缺失株在压力条件下的应激能力减弱,rsbV、rsbW、hpt、clpP、ctsR等环境应激相关基因转录水平均降低.本研究提示σB因子在LM温度、pH和高盐环境应激反应中具有重要的调控作用,这为揭示LM环境应激反应的分子机制及药物作用新靶点的筛选提供了重要的理论依据.%This experiment was conducted to understand the role of the σB factor in regulating the environmental stress of Listeria monocytogenes (LM). We constructed SigmaB gene deletion LM strain by using gene overlap extension PCR (SOE-PCR) and homologous recombination, and the environmental stress response of the strain on the different temperature, different pH condition and high osmotic pressure conditions were detected, and the transcription level of the genes that related with environment stress were tested by using qRT-PCR. The results showed that the environmental stress abilities of the SigmaB gene deletion mutant at the non-suitable conditions weakened and the transcriptional level of genes corresponding to environmental stress (rsbV, rs-bW, hpt, clpP, ctsR) decreased significantly comparing with the standard strain. The results indicated that σB factor plays an important role in responding to environmental stress (temperature,pH and osmotic pressure) of LM. The study provides an important theoretical basis for further studies on its molecular mechanisms of environmental stress response and new target for drug action.