The role of the hok/sok locus in bacterial response to stressful growth conditions
The role of the hok/sok locus in bacterial response to stressful growth conditions
复制标题
DOI：
10.1016/j.micpath.2015.01.009
复制
发表时间：
2015-02-01
影响因子：
3.8
通讯作者：
Good, Liam
中科院分区：
文献类型：
--
作者：
Chukwudi, Chinwe U.;Good, Liam
hok/sok位点以其分离后杀死无质粒的子细胞的质粒稳定作用而闻名。然而，染色体编码基因座的功能（这些基因座在广泛的肠道细菌的致病菌株中更为丰富）尚不清楚。此外，这种毒素/抗毒素依赖系统在多重耐药质粒中频繁出现，表明其具有额外的作用。本研究利用hok/sok质粒研究了hok/sok基因座在高温和抗生素负荷等生长限制条件下对细菌生长的影响。结果表明，hok/sok基因座延长了寄主细胞培养的滞后期，从而使寄主细胞能够适应、响应胁迫，并通过提高指数期的生长速度，最终在这些生长限制条件下茁壮成长。hok/sok位点在低细胞密度培养中也能提高细胞的存活和生长，无论生长条件如何不利，并可能补充现有或有缺陷的SOS机制。除了质粒稳定功能外，这些作用还会增强致病菌建立感染和传播这些质粒上携带的抗生素耐药因子的能力，从而有助于这些细菌的毒力。(C) 2015 Elsevier Ltd.版权所有。
The hok/sok locus is renowned for its plasmid stabilization effect via post-segregational killing of plasmid-free daughter cells. However, the function(s) of the chromosome-encoded loci, which are more abundant in pathogenic strains of a broad range of enteric bacteria, are yet to be understood. Also, the frequent occurrence of this toxin/antitoxin addiction system in multi-drug resistance plasmids suggests additional roles. In this study, the effects of the hok/sok locus on the growth of bacteria in stressful growth-limiting conditions such as high temperature and antibiotic burden were investigated using hok/sok plasmids. The results showed that the hok/sok locus prolonged the lag phase of host cell cultures, thereby enabling the cells to adapt, respond to the stress and eventually thrive in these growth-limiting conditions by increasing the growth rate at exponential phase. The hok/sok locus also enhanced the survival and growth of cells in low cell density cultures irrespective of unfavourable growth conditions, and may complement existing or defective SOS mechanism. In addition to the plasmid stabilization function, these effects would enhance the ability of pathogenic bacteria to establish infections and propagate the antibiotic resistance elements carried on these plasmids, thereby contributing to the virulence of such bacteria. (C) 2015 Elsevier Ltd. All rights reserved.