Listeria monocytogenes is an important food-borne pathogen that is ubiquitous in the environment. It is able to utilize a variety of carbon sources, to produce biofilms on food-processing surfaces and to survive food preservation-associated stresses. In this study, we investigated the effect of three common carbon sources, namely glucose, glycerol and lactose, on growth and activation of the general stress response Sigma factor, SigB, and corresponding phenotypes including stress resistance. A fluorescent reporter coupled to the promoter of lmo2230, a highly SigB-dependent gene, was used to determine SigB activation via quantitative fluorescence spectroscopy. This approach, combined with Western blotting and fluorescence microscopy, showed the highest SigB activation in lactose grown cells and lowest in glucose grown cells. In line with this observation, lactose grown cells showed the highest resistance to lethal heat and acid stress, the highest biofilm formation, and had the highest adhesion/invasion capacity in Caco-2-derived C2Bbe1 cell lines. Our data suggest that lactose utilisation triggers a strong SigB dependent stress response and this may have implications for the resistance of L. monocytogenes along the food chain.

中文翻译：

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不同的碳源导致单核细胞增多性李斯特菌中sigma B的活化不同和抗逆性。

单核细胞增生李斯特菌是一种重要的食源性病原体，在环境中无处不在。它能够利用多种碳源，在食品加工表面上产生生物膜，并能抵抗与食品保存相关的压力。在这项研究中，我们调查了三种常见碳源（葡萄糖，甘油和乳糖）对一般应激反应Sigma因子SigB和相应表型（包括应激抗性）的生长和活化的影响。与高度依赖SigB的基因lmo2230的启动子偶联的荧光报告基因用于通过定量荧光光谱法确定SigB的激活。此方法与Western印迹和荧光显微镜相结合，显示了乳糖生长的细胞中SigB活化最高，而葡萄糖生长的细胞中SigB活化最低。与该观察一致，在Caco-2来源的C2Bbe1细胞系中，乳糖生长的细胞对致命的热和酸胁迫具有最高的抵抗力，具有最高的生物膜形成，并且具有最高的粘附/侵袭能力。我们的数据表明，乳糖利用触发了强烈的SigB依赖性应激反应，这可能对沿食物链的单核细胞增生李斯特氏菌的耐药性产生影响。