Meng Jiao, Huang Can, Huang Xiaoning, Liu Dingyu, Han Beizhong, Chen Jingyu
Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
Front Microbiol. 2020 Feb 5;11:122. doi: 10.3389/fmicb.2020.00122. eCollection 2020.
Fast response to environmental changes plays a key role in the transmission and pathogenesis of . Osmoregulated periplasmic glucans (OPGs) are known to be involved in environmental perception of several pathogens; however, the biological function of OPGs in is still unclear. In this study, we investigated the role of OPGs in by deleting the operon encoding enzymes responsible for OPGs biosynthesis. Complete loss of OPGs in the Δ mutant resulted in decreased motility, c-di-GMP production, biofilm formation and smaller cell size, whereas the overproduction of OPGs through restoration of expression promoted c-di-GMP/biofilm production and increased antibiotic resistance of . Gene expression analysis revealed that deletion reduced transcription of , , and genes regulated by the Rcs phosphorelay system, whereas additional deletion of family genes (, , or ) reversed this effect and restored motility and c-di-GMP/biofilm production but further reduced cell size. Furthermore, disruption of the Rcs phosphorelay increased the motility and promoted the induction of biofilm and c-di-GMP production regulated by OPGs through upregulating the expression of , , and . However, deletion of genes encoding the EnvZ/OmpR phosphorelay downregulated the , and expression, leading to the decreased motility and prevented the induction of biofilm and c-di-GMP production regulated by OPGs. These results indicated that Rcs phosphorelay had the effect on OPGs-mediated functional responses in . Our findings disclose part of the biological role of OPGs and the underlying molecular mechanisms associated with Rcs system in the regulation of the pathogenic phenotype in
对环境变化的快速反应在……的传播和发病机制中起关键作用。已知渗透调节周质葡聚糖（OPGs）参与多种病原体的环境感知；然而，OPGs在……中的生物学功能仍不清楚。在本研究中，我们通过删除编码负责OPGs生物合成的酶的操纵子来研究OPGs在……中的作用。Δ突变体中OPGs的完全缺失导致运动性降低、环二鸟苷酸（c-di-GMP）产生减少、生物膜形成减少以及细胞尺寸变小，而通过恢复……表达来过量产生OPGs则促进了c-di-GMP/生物膜的产生，并增加了……的抗生素抗性。基因表达分析表明，……缺失降低了由Rcs磷酸化信号转导系统调控的……、……、……和……基因的转录，而额外缺失……家族基因（……、……或……）则逆转了这种效应，恢复了运动性和c-di-GMP/生物膜的产生，但进一步减小了细胞尺寸。此外，Rcs磷酸化信号转导的破坏增加了运动性，并通过上调……、……和……的表达促进了由OPGs调控的生物膜诱导和c-di-GMP产生。然而，缺失编码EnvZ/OmpR磷酸化信号转导的基因下调了……、……和……的表达，导致运动性降低，并阻止了由OPGs调控的生物膜诱导和c-di-GMP产生。这些结果表明，Rcs磷酸化信号转导对……中OPGs介导的功能反应有影响。我们的研究结果揭示了OPGs的部分生物学作用以及与Rcs系统相关的潜在分子机制在调节……致病表型中的作用
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