Broad-spectrum tolerance to disinfectant-mediated bacterial killing due to mutation of the PheS aminoacyl tRNA synthetase
Abstract
Disinfectants are essential tools for controlling infectious diseases and maintaining sterile conditions in many medical and food-industry settings. Recent work revealed that a deficiency in the carbohydrate phosphotransferase system (PTS) confers pan-tolerance to killing by diverse disinfectant types through its interaction with the cAMP-CRP regulatory network. The present work characterized a pan-tolerance mutant obtained by enrichment using phenol as a lethal probe and an Escherichia coli PTS null mutant as a parental strain. The resulting super-pan-tolerant mutant, which harbored an F158C substitution in PheS, inhibited bacterial killing by multiple disinfectant classes with surprisingly little effect on antimicrobial lethality. The PheS substitution, which was expected to lower substrate recognition efficiency and result in deacylated tRNA phe occupying the ribosomal A site, activated relA expression and synthesis of ppGpp, even in the absence of disinfectant exposure. ppGpp, along with DksA, increased RpoS function by activating promoters of dsrA and iraP , two genes whose products increase the expression and stability of RpoS. Subsequently, RpoS upregulated the expression of genes encoding a universal stress protein (UspB) and an oxidative stress peroxidase (KatE), which preconditioned bacteria to better survive a variety of disinfectants. Disinfectant-mediated accumulation of reactive oxygen species (ROS) and bacterial killing were abolished/reduced by exogenous dimethyl sulfoxide and by a PheS F158C substitution up-regulating genes encoding ROS-detoxifying enzymes ( katE, sodA, oxyR, ahpC ). These data identify a pheS mutation-triggered, ppGpp-stimulated transcriptional regulatory cascade that negates biocide-mediated lethality, thereby tying the stringent response to protection from ROS-mediated biocide lethality.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (15)
Miaomiao Chen
Runbo Cui
State Key Laboratory of Vaccines for Infectious Diseases, Xiang-An Biomedicine Laboratory, Department of Laboratory Medicine, School of Public Health, Xiamen University
Shouqiang Hong
State Key Laboratory of Vaccines for Infectious Diseases, Xiang-An Biomedicine Laboratory, Department of Laboratory Medicine, School of Public Health, Xiamen University
Weiwei Zhu
Division of Plant Science and Technology, University of Missouri
Qiong Yang
State Key Laboratory of Vaccines for Infectious Diseases, Xiang-An Biomedicine Laboratory, Department of Laboratory Medicine, School of Public Health, Xiamen University
Jiahao Li
Zihan Nie
State Key Laboratory of Vaccines for Infectious Diseases, Xiang-An Biomedicine Laboratory, Department of Laboratory Medicine, School of Public Health, Xiamen University
Xue Zhang
Yanghui Ye
Minister of Education Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, Institute of Molecular Enzymology, School of Biology and Basic Medical Sciences, Soochow University
Yunxin Xue
State Key Laboratory of Vaccines for Infectious Diseases, Xiang-An Biomedicine Laboratory, Department of Laboratory Medicine, School of Public Health, Xiamen University
Dai Wang
State Key Laboratory of Vaccines for Infectious Diseases, Xiang-An Biomedicine Laboratory, Department of Laboratory Medicine, School of Public Health, Xiamen University
Yuzhi Hong
Minister of Education Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, Institute of Molecular Enzymology, School of Biology and Basic Medical Sciences, Soochow University
Karl Drlica
Public Health Research Institute and Department of Microbiology, Biochemistry & Molecular Genetics, New Jersey Medical School, Rutgers University
Jianjun Niu
Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University
Xilin Zhao
State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, Haihe Laboratory of Sustainable Chemical Transformations, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, China