Handley Rebecca A, Mulholland Francis, Reuter Mark, Ramachandran Vinoy K, Musk Heather, Clissold Leah, Le Brun Nick E, van Vliet Arnoud H M
1 Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK 2 Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
1 Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
Microbiology (Reading). 2015 Jul;161(7):1524-36. doi: 10.1099/mic.0.000109. Epub 2015 May 12.
The foodborne bacterial pathogen Campylobacter jejuni is an obligate microaerophile that is exposed to atmospheric oxygen during transmission through the food chain. Survival under aerobic conditions requires the concerted control of oxidative stress systems, which in C. jejuni are intimately connected with iron metabolism via the PerR and Fur regulatory proteins. Here, we have characterized the roles of C. jejuni PerR in oxidative stress and motility phenotypes, and its regulon at the level of transcription, protein expression and promoter interactions. Insertional inactivation of perR in the C. jejuni reference strains NCTC 11168, 81-176 and 81116 did not result in any growth deficiencies, but strongly increased survival in atmospheric oxygen conditions, and allowed growth around filter discs infused with up to 30 % H2O2 (8.8 M). Expression of catalase, alkyl hydroperoxide reductase, thioredoxin reductase and the Rrc desulforubrerythrin was increased in the perR mutant, and this was mediated at the transcriptional level as shown by electrophoretic mobility shift assays of the katA, ahpC and trxB promoters using purified PerR. Differential RNA-sequencing analysis of a fur perR mutant allowed the identification of eight previously unknown transcription start sites of genes controlled by Fur and/or PerR. Finally, inactivation of perR in C. jejuni did not result in reduced motility, and did not reduce killing of Galleria melonella wax moth larvae. In conclusion, PerR plays an important role in controlling oxidative stress resistance and aerobic survival of C. jejuni, but this role does not extend into control of motility and associated phenotypes.
食源性病原体空肠弯曲菌是一种专性微需氧菌，在通过食物链传播过程中会暴露于大气氧中。在有氧条件下存活需要氧化应激系统的协同调控，在空肠弯曲菌中，该系统通过PerR和Fur调控蛋白与铁代谢密切相关。在此，我们表征了空肠弯曲菌PerR在氧化应激和运动表型中的作用，以及其在转录、蛋白质表达和启动子相互作用水平上的调控子。在空肠弯曲菌参考菌株NCTC 11168、81 - 176和81116中对perR进行插入失活，并未导致任何生长缺陷，但显著提高了在大气氧条件下的存活率，并允许在注入高达30% H2O2（8.8 M）的滤纸片周围生长。在perR突变体中，过氧化氢酶、烷基过氧化氢还原酶、硫氧还蛋白还原酶和Rrc去磺基紫红素的表达增加，如使用纯化的PerR对katA、ahpC和trxB启动子进行电泳迁移率变动分析所示，这是在转录水平介导的。对fur perR突变体进行差异RNA测序分析，鉴定出了8个先前未知的受Fur和/或PerR控制的基因转录起始位点。最后，在空肠弯曲菌中perR失活并未导致运动性降低，也未减少对大蜡螟幼虫的杀伤。总之，PerR在控制空肠弯曲菌的氧化应激抗性和有氧存活中起重要作用，但该作用并不扩展到对运动性和相关表型的控制。
