Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China.
Department of Physiology, School of Medicine, Zhejiang University, Hangzhou, China.
Infect Immun. 2018 May 22;86(6). doi: 10.1128/IAI.00090-18. Print 2018 Jun.
Mechanosensitive channels are ubiquitous in bacteria and provide an essential mechanism to survive sudden exposure to a hypo-osmotic environment by the sensing and release of increased turgor pressure. No mechanosensitive channels have thus far been identified and characterized for the human-specific bacterial pathogen In this study, we identified and characterized the MscS-like mechanosensitive channel (Ng-MscS). Electrophysiological analyses by the patch clamp method showed that Ng-MscS is stretch activated and contains pressure-dependent gating properties. Further mutagenesis studies of critical residues forming the hydrophobic vapor lock showed that gain-of-function mutations in Ng-MscS inhibited bacterial growth. Subsequent analysis of the function of Ng-MscS in by osmotic down-shock assays revealed that the survival of Ng- deletion mutants was significantly reduced compared with that of wild-type strains, while down-shock survival was restored upon the ectopic complementation of Finally, to investigate whether Ng-MscS is important for during infections, competition assays were performed by using a murine vaginal tract infection model. Ng- deletion mutants were outcompeted by wild-type strains for colonization and survival in this infection model, highlighting that Ng-MscS contributes to colonization and survival. Therefore, Ng-MscS might be a promising target for the future development of novel antimicrobials.
机械敏感通道在细菌中普遍存在,为细菌提供了一种重要的机制,使其能够在突然暴露于低渗环境时,通过感知和释放增加的膨压来存活。到目前为止,尚未为人类特有的细菌病原体 鉴定和表征机械敏感通道。在这项研究中,我们鉴定并表征了 MscS 样机械敏感通道(Ng-MscS)。膜片钳方法的电生理分析表明,Ng-MscS 是拉伸激活的,并具有压力依赖性的门控特性。进一步对形成疏水性蒸汽锁的关键残基进行突变研究表明,Ng-MscS 的功能获得性突变抑制了细菌的生长。随后通过渗透压休克试验分析 Ng-MscS 在 中的功能,发现 Ng-缺失突变体的存活明显低于野生型菌株,而在异位互补 Ng-MscS 后,存活得到恢复。最后,为了研究 Ng-MscS 是否对感染期间的 重要,通过使用鼠阴道感染模型进行了竞争试验。在该感染模型中,Ng-缺失突变体在定殖和存活方面被 野生型菌株所淘汰,这突出表明 Ng-MscS 有助于 定殖和存活。因此,Ng-MscS 可能是未来开发新型抗菌药物的有前途的靶点。