Gene profiling-based phenotyping for identification of cellular parameters that contribute to fitness, stress-tolerance and virulence of Listeria monocytogenes variants
Gene profiling-based phenotyping for identification of cellular parameters that contribute to fitness, stress-tolerance and virulence of Listeria monocytogenes variants
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DOI：
10.1016/j.ijfoodmicro.2018.06.003
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发表时间：
2018-10-20
影响因子：
5.4
通讯作者：
Abee, Tjakko
中科院分区：
文献类型：
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作者：
Koomen, Jeroen;den Besten, Heidy M. W.;Abee, Tjakko
微生物种群的异质性使得微生物对环境压力产生不同的反应，并可能导致选择出抗压变体。在这项研究中，我们使用了单核细胞增生李斯特氏菌LO28的两种不同抗压变体，它们在编码核糖体蛋白S21的rpsU基因上存在突变，通过比较基因图谱分析和表型分析方法来阐明有助于适应性、抗压性以及与宿主相互作用的特征。转录组分析表明，在两种rpsU变体中，有116个基因上调，114个基因下调。上调的基因包括受SigB调控的基因的主要贡献，例如与细胞内耐酸相关的谷氨酸脱羧酶（GAD）（gad3）、参与相容性溶质摄取的基因（opuC）、甘油代谢基因（glpF、glpK、glpD）以及毒力基因（inlA、inlB）。两种变体中下调的基因主要涉及鞭毛合成和运动相关的基因。两种rpsU变体的表型结果与基因图谱数据相符，包括可能与相容性溶质积累相关的抗冻性增强、更高的甘油利用率以及可能与内化素更高表达相关的对Caco - 2细胞更好的粘附性。此外，明场和电子显微镜分析证实变体的鞭毛减少。SigB介导的应激防御的激活为rpsU变体的多重抗压表型提供了解释。
Microbial population heterogeneity allows for a differential microbial response to environmental stresses and can lead to the selection of stress resistant variants. In this study, we have used two different stress resistant variants of Listeria monocytogenes LO28 with mutations in the rpsU gene encoding ribosomal protein S21, to elucidate features that can contribute to fitness, stress-tolerance and host interaction using a comparative gene profiling and phenotyping approach. Transcriptome analysis showed that 116 genes were upregulated and 114 genes were downregulated in both rpsU variants. Upregulated genes included a major contribution of SigB-controlled genes such as intracellular acid resistance-associated glutamate decarboxylase (GAD) (gad3), genes involved in compatible solute uptake (opuC), glycerol metabolism (glpF, glpK, glpD), and virulence (inlA, inlB). Downregulated genes in the two variants involved mainly genes involved in flagella synthesis and motility. Phenotyping results of the two rpsU variants matched the gene profiling data including enhanced freezing resistance conceivably linked to compatible solute accumulation, higher glycerol utilisation rates, and better adhesion to Caco 2 cells presumably linked to higher expression of internalins. Also, bright field and electron microscopy analysis confirmed reduced flagellation of the variants. The activation of SigB-mediated stress defence offers an explanation for the multiple-stress resistant phenotype in rpsU variants.