革兰氏阴性菌的Tol-Pal系统是维持外膜完整性所必需的。它是五种包膜蛋白的多蛋白复合物,TolQ,TolR,托拉,TolB,还有伙计.这些蛋白质最初是在大肠杆菌中研究的,随后在许多其他细菌属中被鉴定。然而,Tol-pa系统在霍乱沙门氏菌发病机制中的功能尚不清楚。这里,我们报道了这三种蛋白在猪链球菌表型和生物学中的作用.我们发现tolA中的突变,tolB,tolR对细胞壁造成了严重破坏,通过观察球形的微观结构,长链,鞭毛缺陷,和膜起泡。我们证实,当暴露于脱氧胆酸钠时,所有突变体均显着降低了猪链球菌的存活率,并表现出对万古霉素的高度敏感性。这可以解释为包膜完整性的破坏。此外,tola,tolB,和tolR突变体在小鼠感染模型中显示出减弱的毒力。这可以解释为突变体中的一系列缺陷表型,如信封完整性的严重缺陷,增长,和运动性。进一步的研究表明,所有基因都参与了外膜囊泡(OMV)的生物发生。有趣的是,与野生型猪链球菌的OMV相比,用ΔtolB的OMV免疫有效地增强了鼠的生存力。表明其在疫苗接种策略中的潜在用途。总的来说,这项研究提供了对S.CholeraesuisTol-pa系统的生物学作用的见解。
The Tol-Pal system of Gram-negative bacteria is necessary for maintaining outer membrane integrity. It is a multiprotein complex of five envelope proteins, TolQ,
TolR, TolA, TolB, and Pal. These proteins were first investigated in E. coli, and subsequently been identified in many other bacterial genera. However, the function of the Tol-Pal system in Salmonella Choleraesuis pathogenesis is still unclear. Here, we reported the role of three of these proteins in the phenotype and biology of S. Choleraesuis. We found that mutations in tolA, tolB, and
tolR caused severe damage to the cell wall, which was supported by observing the microstructure of spherical forms, long chains, flagella defects, and membrane blebbing. We confirmed that all the mutants significantly decreased S. Choleraesuis survival when exposed to sodium deoxycholate and exhibited a high sensitivity to vancomycin, which may be explained by the disruption of envelope integrity. In addition, tolA, tolB, and
tolR mutants displayed attenuated virulence in a mouse infection model. This could be interpreted as a series of defective phenotypes in the mutants, such as severe defects in envelope integrity, growth, and motility. Further investigation showed that all the genes participate in outer membrane vesicles (OMVs) biogenesis. Interestingly, immunization with OMVs from ΔtolB efficiently enhanced murine viability in contrast to OMVs from the wild-type S. Choleraesuis, suggesting its potential use in vaccination strategies. Collectively, this study provides an insight into the biological role of the S. Choleraesuis Tol-Pal system.