Ryan E M, Gahan C G M, Hill C
Department of Microbiology, University College Cork, Cork, Ireland.
Lett Appl Microbiol. 2008 Feb;46(2):148-54. doi: 10.1111/j.1472-765X.2007.02280.x. Epub 2007 Dec 7.
To investigate the contribution of the alternative sigma factor Sigma B to detergent stress in Listeria monocytogenes upon exposure to the surface-active agents, benzalkoniumchloride (BC), cetylpyridinium chloride (CPC) and sodium docecyl sulfate (SDS).
Surfactant/detergent stress in L. monocytogenes 10403S and a DeltasigB mutant of 10403S was investigated by lethality, impact on growth and by transcriptional analysis. We observed a significant 1-2 log decrease in the viability of the DeltasigB mutant in response to lethal levels of surfactants. Transcriptional (reverse transcriptase-PCR) analysis revealed the induction of sigmaB by sublethal levels of surface-active agents. However, Sigma B does not play a significant role in the growth of L. monocytogenes upon exposure to sublethal levels as investigated by growth analysis.
Sigma B is essential for the resistance of L. monocytogenes at lethal levels of BC, CPC and SDS.
We demonstrate that Sigma B is essential for the resistance of the pathogen to surfactant stress. The findings raise the possibility that induction of Sigma B by sublethal levels of industrial cleaning agents may promote enhanced resistance of further food-processing associated stresses or conditions encountered during infection. Sigma B-regulated mechanisms of detergent resistance may provide targets for the future design of novel cleaning agents.
研究替代σ因子Sigma B在单核细胞增生李斯特菌暴露于表面活性剂苯扎氯铵（BC）、十六烷基吡啶氯化物（CPC）和十二烷基硫酸钠（SDS）时对洗涤剂应激的作用。
通过致死率、对生长的影响以及转录分析，研究了单核细胞增生李斯特菌10403S及其10403S的ΔsigB突变体中的表面活性剂/洗涤剂应激。我们观察到，在致死水平的表面活性剂作用下，ΔsigB突变体的活力显著下降1-2个对数。转录（逆转录-PCR）分析显示，亚致死水平的表面活性剂可诱导sigmaB。然而，如生长分析所示，在暴露于亚致死水平时，Sigma B在单核细胞增生李斯特菌的生长中并不起重要作用。
Sigma B对于单核细胞增生李斯特菌在BC、CPC和SDS致死水平下的抗性至关重要。
我们证明Sigma B对于病原体抵抗表面活性剂应激至关重要。这些发现增加了一种可能性，即工业清洁剂的亚致死水平诱导Sigma B可能会增强对进一步的食品加工相关应激或感染期间遇到的条件的抗性。Sigma B调节的洗涤剂抗性机制可能为新型清洁剂的未来设计提供靶点。
