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Ma X, Nugraha DK, Hiramatsu Y, Horiguchi Y. RpoN (sigma factor 54) contributes to bacterial fitness during tracheal colonization of Bordetella bronchiseptica. Microbiol Immunol 2024; 68:36-46. [PMID: 38105571 DOI: 10.1111/1348-0421.13109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/02/2023] [Accepted: 12/03/2023] [Indexed: 12/19/2023]
Abstract
The Gram-negative pathogenic bacterium Bordetella bronchiseptica is a respiratory pathogen closely related to Bordetella pertussis, the causative agent of whooping cough. Despite sharing homologous virulence factors, B. bronchiseptica infects a broad range of mammalian hosts, including some experimental animals, whereas B. pertussis is strictly adapted to humans. Therefore, B. bronchiseptica is often used as a representative model to explore the pathogenicity of Bordetella in infection experiments with laboratory animals. Although Bordetella virulence factors, including toxins and adhesins have been studied well, our recent study implied that unknown virulence factors are involved in tracheal colonization and infection. Here, we investigated bacterial genes contributing to tracheal colonization by high-throughput transposon sequencing (Tn-seq). After the screening, we picked up 151 candidate genes of various functions and found that a rpoN-deficient mutant strain was defective in tracheal colonization when co-inoculated with the wild-type strain. rpoN encodes σ54 , a sigma factor that regulates the transcription of various genes, implying its contribution to various bacterial activities. In fact, we found RpoN of B. bronchiseptica is involved in bacterial motility and initial biofilm formation. From these results, we propose that RpoN supports bacterial colonization by regulating various bacteriological functions.
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Affiliation(s)
- Xingyan Ma
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Dendi K Nugraha
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yukihiro Hiramatsu
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yasuhiko Horiguchi
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
- Center for Infectious Disease Education and Research, Osaka University, Osaka, Japan
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2
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Yang HW, Lee JH, Zhao Y. RpoN Regulon in Erwinia amylovora Revealed by Transcriptional Profiling and In Silico Binding Site Analysis. PHYTOPATHOLOGY 2023; 113:183-193. [PMID: 35994732 DOI: 10.1094/phyto-07-22-0255-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Erwinia amylovora causes a devastating fire blight disease in apples and pears. One of the main virulence determinants in E. amylovora is the hypersensitive response (HR) and pathogenicity (hrp)-type III secretion system (T3SS), which is activated by the RpoN-HrpL sigma factor cascade. However, the RpoN regulon in E. amylovora has not been investigated. In this study, we determined the RpoN regulon in E. amylovora by combining RNA-seq transcriptomic analysis with in silico binding site analysis. RNA-seq revealed that 262 genes, approximately 7.5% genes in the genome of E. amylovora, were differentially transcribed in the rpoN mutant as compared with the wild type. Specifically, genes associated with virulence, motility, nitrogen assimilation, the PspF system, stress response, and arginine biosynthesis are positively regulated by RpoN, whereas genes associated with biosynthesis of amino acids and sorbitol transport are negatively regulated by RpoN. In silico binding site analysis identified 46 potential target genes with a putative RpoN binding site, and the upstream sequences of six, three, and three genes also contain putative GlnG, PspF, and YfhA binding sites, respectively. Overall, RpoN directly regulates genes associated with virulence, nitrogen assimilation, the PspF system, motility and the YfhA/YfhK two-component regulatory system.
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Affiliation(s)
- Ho-Wen Yang
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S.A
| | - Jae-Hoon Lee
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S.A
| | - Youfu Zhao
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S.A
- Department of Plant Pathology, WSU-IAREC, Prosser, WA 99350, U.S.A
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Liu Y, Gao J, Wang N, Li X, Fang N, Zhuang X. Diffusible signal factor enhances the saline-alkaline resistance and rhizosphere colonization of Stenotrophomonas rhizophila by coordinating optimal metabolism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 834:155403. [PMID: 35469877 DOI: 10.1016/j.scitotenv.2022.155403] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/15/2022] [Accepted: 04/16/2022] [Indexed: 06/14/2023]
Abstract
Quorum sensing (QS) regulates various physiological processes in a cell density-dependent mode via cell-cell communication. Stenotrophomonas rhizophila DSM14405T having the diffusible signal factor (DSF)-QS system, is a plant growth-promoting rhizobacteria (PGPR) that enables host plants to tolerate saline-alkaline stress. However, the regulatory mechanism of DSF-QS in S. rhizophila is not fully understood. In this study, we used S. rhizophila DSM14405T wild-type (WT) and an incompetent DSF production rpfF-knockout mutant to explore the regulatory role of QS in S. rhizophila growth, stress responses, biofilm formation, and colonization under saline-alkaline stress. We found that a lack of DSF-QS reduces the tolerance of S. rhizosphere ΔrpfF to saline-alkaline stress, with a nearly 25-fold reduction in the ΔrpfF population compared with WT at 24 h under stress. Transcriptome analysis revealed that QS helps S. rhizophila WT respond to saline-alkaline stress by enhancing metabolism associated with the cell wall and membrane, oxidative stress response, cell adhesion, secretion systems, efflux pumps, and TonB systems. These metabolic systems enhance penetration defense, Na+ efflux, iron uptake, and reactive oxygen species scavenging. Additionally, the absence of DSF-QS causes overexpression of biofilm-associated genes under the regulation of sigma 54 and other transcriptional regulators. However, greater biofilm formation capacity confers no advantage on S. rhizosphere ΔrpfF in rhizosphere colonization. Altogether, our results show the importance of QS in PGPR growth and colonization; QS gives PGPR a collective adaptive advantage in harsh natural environments.
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Affiliation(s)
- Ying Liu
- CAS Key Laboratory of Environment Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Life Sciences, Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Jie Gao
- CAS Key Laboratory of Environment Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Na Wang
- CAS Key Laboratory of Environment Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xianglong Li
- CAS Key Laboratory of Environment Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Na Fang
- CAS Key Laboratory of Environment Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Institute of International Rivers and Eco-security, Yunan University, Kunming 650500, China
| | - Xuliang Zhuang
- CAS Key Laboratory of Environment Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
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4
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Mandal RK, Jiang T, Kwon YM. Genetic Determinants in Salmonella enterica Serotype Typhimurium Required for Overcoming In Vitro Stressors in the Mimicking Host Environment. Microbiol Spectr 2021; 9:e0015521. [PMID: 34878334 PMCID: PMC8653844 DOI: 10.1128/spectrum.00155-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 10/29/2021] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serotype Typhimurium, a nontyphoidal Salmonella (NTS), results in a range of enteric diseases, representing a major disease burden worldwide. There is still a significant portion of Salmonella genes whose mechanistic basis to overcome host innate defense mechanisms largely remains unknown. Here, we have applied transposon insertion sequencing (Tn-seq) method to unveil the genetic factors required for the growth or survival of S. Typhimurium under various host stressors simulated in vitro. A highly saturating Tn5 library of S. Typhimurium 14028s was subjected to selection during growth in the presence of short-chain fatty acid (100 mM propionate), osmotic stress (3% NaCl), or oxidative stress (1 mM H2O2) or survival in extreme acidic pH (30 min in pH 3) or starvation (12 days in 1× phosphate-buffered saline [PBS]). We have identified a total of 339 conditionally essential genes (CEGs) required to overcome at least one of these conditions mimicking host insults. Interestingly, all eight genes encoding FoF1-ATP synthase subunit proteins were required for fitness in all five stresses. Intriguingly, a total of 88 genes in Salmonella pathogenicity islands (SPI), including SPI-1, SPI-2, SPI-3, SPI-5, SPI-6, and SPI-11, are also required for fitness under the in vitro conditions. Additionally, by comparative analysis of the genes identified in this study and the genes previously shown to be required for in vivo fitness, we identified novel genes (marBCT, envF, barA, hscA, rfaQ, rfbI, and the genes encoding putative proteins STM14_1138, STM14_3334, STM14_4825, and STM_5184) that have compelling potential for the development of vaccines and antibacterial drugs to curb Salmonella infection. IMPORTANCE Salmonella enterica serotype Typhimurium is a major human bacterial pathogen that enters the food chain through meat animals asymptomatically carrying this pathogen. Despite the rich genome sequence data, a significant portion of Salmonella genes remain to be characterized for their potential contributions to virulence. In this study, we used transposon insertion sequencing (Tn-seq) to elucidate the genetic factors required for growth or survival under various host stressors, including short-chain fatty acids, osmotic stress, oxidative stress, extreme acid, and starvation. Among the total of 339 conditionally essential genes (CEGs) that are required under at least one of these five stress conditions were 221 previously known virulence genes required for in vivo fitness during infection in at least one of four animal species, including mice, chickens, pigs, and cattle. This comprehensive map of virulence phenotype-genotype in S. Typhimurium provides a roadmap for further interrogation of the biological functions encoded by the genome of this important human pathogen to survive in hostile host environments.
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Affiliation(s)
- Rabindra K. Mandal
- Center of Excellence for Poultry Science, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
| | - Tieshan Jiang
- Center of Excellence for Poultry Science, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
| | - Young Min Kwon
- Center of Excellence for Poultry Science, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, Arkansas, USA
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5
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Liu X, Ye Y, Zhu Y, Wang L, Yuan L, Zhu J, Sun A. Involvement of RpoN in Regulating Motility, Biofilm, Resistance, and Spoilage Potential of Pseudomonas fluorescens. Front Microbiol 2021; 12:641844. [PMID: 34135871 PMCID: PMC8202526 DOI: 10.3389/fmicb.2021.641844] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/30/2021] [Indexed: 11/17/2022] Open
Abstract
Pseudomonas fluorescens is a typical spoiler of proteinaceous foods, and it is characterized by high spoilage activity. The sigma factor RpoN is a well-known regulator controlling nitrogen assimilation and virulence in many pathogens. However, its exact role in regulating the spoilage caused by P. fluorescens is unknown. Here, an in-frame deletion mutation of rpoN was constructed to investigate its global regulatory function through phenotypic and RNA-seq analysis. The results of phenotypic assays showed that the rpoN mutant was deficient in swimming motility, biofilm formation, and resistance to heat and nine antibiotics, while the mutant increased the resistance to H2O2. Moreover, the rpoN mutant markedly reduced extracellular protease and total volatile basic nitrogen (TVB-N) production in sterilized fish juice at 4°C; meanwhile, the juice with the rpoN mutant showed significantly higher sensory scores than that with the wild-type strain. To identify RpoN-controlled genes, RNA-seq-dependent transcriptomics analysis of the wild-type strain and the rpoN mutant was performed. A total of 1224 genes were significantly downregulated, and 474 genes were significantly upregulated by at least two folds at the RNA level in the rpoN mutant compared with the wild-type strain, revealing the involvement of RpoN in several cellular processes, mainly flagellar mobility, adhesion, polysaccharide metabolism, resistance, and amino acid transport and metabolism; this may contribute to the swimming motility, biofilm formation, stress and antibiotic resistance, and spoilage activities of P. fluorescens. Our results provide insights into the regulatory role of RpoN of P. fluorescens in food spoilage, which can be valuable to ensure food quality and safety.
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Affiliation(s)
- Xiaoxiang Liu
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Yifan Ye
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Yin Zhu
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Lifang Wang
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Leyang Yuan
- Zhejiang Museum of Natural History, Hangzhou, China
| | - Junli Zhu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, China
| | - Aihua Sun
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
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6
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Duqué B, Rezé S, Rossero A, Membré JM, Guillou S, Haddad N. Quantification of Campylobacter jejuni gene expression after successive stresses mimicking poultry slaughtering steps. Food Microbiol 2021; 98:103795. [PMID: 33875223 DOI: 10.1016/j.fm.2021.103795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/05/2021] [Accepted: 03/23/2021] [Indexed: 12/31/2022]
Abstract
Broiler meat is considered as the most important source of the foodborne pathogen Campylobacter jejuni. Exposure to stress conditions encountered during the slaughtering process may induce bacterial adaptation mechanisms, and enhance or decrease pathogen resistance to subsequent stress. This adaptation may result from changes in bacterial gene expression. This study aims to accurately quantify the expression of selected C. jejuni genes after stresses inspired from the poultry slaughtering process. RT-qPCR was used to quantify gene expression of 44 genes in three strains after successive heat and cold stresses. Main results indicated that 26 genes out of 44 were differentially expressed following the successive thermal stresses. Three clusters of genes were differentially expressed according to the strain and the stress condition. Up-regulated genes mainly included genes involved in the heat shock response, whereas down-regulated genes belonged to metabolic pathways (such as lipid, amino-acid metabolisms). However, four genes were similarly overexpressed in the three strains; they might represent indicators of the thermal stress response at the species scale. Advances in the molecular understanding of the stress response of pathogenic bacteria, such as Campylobacter, in real-life processing conditions will make it possible to identify technological levers and better mitigate the microbial risk.
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Affiliation(s)
- Benjamin Duqué
- SECALIM, INRAE, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | - Sandrine Rezé
- SECALIM, INRAE, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | - Albert Rossero
- SECALIM, INRAE, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | | | - Sandrine Guillou
- SECALIM, INRAE, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | - Nabila Haddad
- SECALIM, INRAE, Oniris, Université Bretagne Loire, 44307, Nantes, France.
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Kim SH, Chelliah R, Ramakrishnan SR, Perumal AS, Bang WS, Rubab M, Daliri EBM, Barathikannan K, Elahi F, Park E, Jo HY, Hwang SB, Oh DH. Review on Stress Tolerance in Campylobacter jejuni. Front Cell Infect Microbiol 2021; 10:596570. [PMID: 33614524 PMCID: PMC7890702 DOI: 10.3389/fcimb.2020.596570] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 12/03/2020] [Indexed: 01/17/2023] Open
Abstract
Campylobacter spp. are the leading global cause of bacterial colon infections in humans. Enteropathogens are subjected to several stress conditions in the host colon, food complexes, and the environment. Species of the genus Campylobacter, in collective interactions with certain enteropathogens, can manage and survive such stress conditions. The stress-adaptation mechanisms of Campylobacter spp. diverge from other enteropathogenic bacteria, such as Escherichia coli, Salmonella enterica serovar Typhi, S. enterica ser. Paratyphi, S. enterica ser. Typhimurium, and species of the genera Klebsiella and Shigella. This review summarizes the different mechanisms of various stress-adaptive factors on the basis of species diversity in Campylobacter, including their response to various stress conditions that enhance their ability to survive on different types of food and in adverse environmental conditions. Understanding how these stress adaptation mechanisms in Campylobacter, and other enteric bacteria, are used to overcome various challenging environments facilitates the fight against resistance mechanisms in Campylobacter spp., and aids the development of novel therapeutics to control Campylobacter in both veterinary and human populations.
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Affiliation(s)
- Se-Hun Kim
- Food Microbiology Division, Food Safety Evaluation Department, National Institute of Food and Drug Safety Evaluation, Cheongju, South Korea.,College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Ramachandran Chelliah
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Sudha Rani Ramakrishnan
- School of Food Science, Department of Food Science and Biotechnology, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | | | - Woo-Suk Bang
- Department of Food and Nutrition, College of Human Ecology and Kinesiology, Yeungnam University, Gyeongsan, South Korea
| | - Momna Rubab
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Eric Banan-Mwine Daliri
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Kaliyan Barathikannan
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Fazle Elahi
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Eunji Park
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Hyeon Yeong Jo
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Su-Bin Hwang
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Deog Hwan Oh
- College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
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8
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Mouftah SF, Cobo-Díaz JF, Álvarez-Ordóñez A, Mousa A, Calland JK, Pascoe B, Sheppard SK, Elhadidy M. Stress resistance associated with multi-host transmission and enhanced biofilm formation at 42 °C among hyper-aerotolerant generalist Campylobacter jejuni. Food Microbiol 2020; 95:103706. [PMID: 33397624 DOI: 10.1016/j.fm.2020.103706] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 02/08/2023]
Abstract
One of the emerging conundrums of Campylobacter food-borne illness is the bacterial ability to survive stressful environmental conditions. We evaluated the heterogeneity among 90 C. jejuni and 21 C. coli isolates from different sources in Egypt with respect to biofilm formation capabilities (under microaerobic and aerobic atmosphere) and resistance to a range of stressors encountered along the food chain (aerobic stress, refrigeration, freeze-thaw, heat, peracetic acid, and osmotic stress). High prevalence (63%) of hyper-aerotolerant (HAT) isolates was observed, exhibiting also a significantly high tolerance to heat, osmotic stress, refrigeration, and freeze-thaw stress, coupled with high biofilm formation ability which was clearly enhanced under aerobic conditions, suggesting a potential link between stress adaptation and biofilm formation. Most HAT multi-stress resistant and strong biofilm producing C. jejuni isolates belonged to host generalist clonal complexes (ST-21, ST-45, ST-48 and ST-206). These findings highlight the potential role of oxidative stress response systems in providing cross-protection (resistance to other multiple stress conditions) and enhancing biofilm formation in Campylobacter and suggest that selective pressures encountered in hostile environments have shaped the epidemiology of C. jejuni in Egypt by selecting the transmission of highly adapted isolates, thus promoting the colonization of multiple host species by important disease-causing lineages.
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Affiliation(s)
- Shaimaa F Mouftah
- University of Science and Technology, Zewail City of Science and Technology, Giza, Egypt
| | - José F Cobo-Díaz
- Department of Food Hygiene and Technology and Institute of Food Science and Technology, Universidad de León, Spain
| | - Avelino Álvarez-Ordóñez
- Department of Food Hygiene and Technology and Institute of Food Science and Technology, Universidad de León, Spain
| | - Ahmed Mousa
- University of Science and Technology, Zewail City of Science and Technology, Giza, Egypt
| | - Jessica K Calland
- The Milner Centre of Evolution, University of Bath, Claverton Down, Bath, UK
| | - Ben Pascoe
- The Milner Centre of Evolution, University of Bath, Claverton Down, Bath, UK; Chiang Mai University, Chiang Mai, Thailand
| | - Samuel K Sheppard
- The Milner Centre of Evolution, University of Bath, Claverton Down, Bath, UK; Chiang Mai University, Chiang Mai, Thailand; Department of Zoology, University of Oxford, Oxford, UK
| | - Mohamed Elhadidy
- University of Science and Technology, Zewail City of Science and Technology, Giza, Egypt; Department of Bacteriology, Mycology and Immunology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt.
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9
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Sher AA, Jerome JP, Bell JA, Yu J, Kim HY, Barrick JE, Mansfield LS. Experimental Evolution of Campylobacter jejuni Leads to Loss of Motility, rpoN (σ54) Deletion and Genome Reduction. Front Microbiol 2020; 11:579989. [PMID: 33240235 PMCID: PMC7677240 DOI: 10.3389/fmicb.2020.579989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/14/2020] [Indexed: 12/18/2022] Open
Abstract
Evolution experiments in the laboratory have focused heavily on model organisms, often to the exclusion of clinically relevant pathogens. The foodborne bacterial pathogen Campylobacter jejuni belongs to a genus whose genomes are small compared to those of its closest genomic relative, the free-living genus Sulfurospirillum, suggesting genome reduction during the course of evolution to host association. In an in vitro experiment, C. jejuni serially passaged in rich medium in the laboratory exhibited loss of flagellar motility-an essential function for host colonization. At early time points the motility defect was often reversible, but after 35 days of serial culture, motility was irreversibly lost in most cells in 5 independently evolved populations. Population re-sequencing revealed disruptive mutations to genes in the flagellar transcriptional cascade, rpoN (σ54)-therefore disrupting the expression of the genes σ54 regulates-coupled with deletion of rpoN in all evolved lines. Additional mutations were detected in virulence-related loci. In separate in vivo experiments, we demonstrate that a phase variable (reversible) motility mutant carrying an adenine deletion within a homopolymeric tract resulting in truncation of the flagellar biosynthesis gene fliR was deficient for colonization in a C57BL/6 IL-10-/- mouse disease model. Re-insertion of an adenine residue partially restored motility and ability to colonize mice. Thus, a pathogenic C. jejuni strain was rapidly attenuated by experimental laboratory evolution and demonstrated genomic instability during this evolutionary process. The changes observed suggest C. jejuni is able to evolve in a novel environment through genome reduction as well as transition, transversion, and slip-strand mutations.
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Affiliation(s)
- Azam A. Sher
- Comparative Enteric Diseases Laboratory, East Lansing, MI, United States
- Comparative Medicine and Integrative Biology, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, United States
| | - John P. Jerome
- Comparative Enteric Diseases Laboratory, East Lansing, MI, United States
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Julia A. Bell
- Comparative Enteric Diseases Laboratory, East Lansing, MI, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Julian Yu
- Comparative Enteric Diseases Laboratory, East Lansing, MI, United States
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Hahyung Y. Kim
- Comparative Enteric Diseases Laboratory, East Lansing, MI, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Jeffrey E. Barrick
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, United States
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - Linda S. Mansfield
- Comparative Enteric Diseases Laboratory, East Lansing, MI, United States
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
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10
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Riedel C, Förstner KU, Püning C, Alter T, Sharma CM, Gölz G. Differences in the Transcriptomic Response of Campylobacter coli and Campylobacter lari to Heat Stress. Front Microbiol 2020; 11:523. [PMID: 32292399 PMCID: PMC7118207 DOI: 10.3389/fmicb.2020.00523] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 03/10/2020] [Indexed: 12/17/2022] Open
Abstract
Campylobacter spp. are one of the most important food-borne pathogens, which are quite susceptible to environmental or technological stressors compared to other zoonotic bacteria. This might be due to the lack of many stress response mechanisms described in other bacteria. Nevertheless, Campylobacter is able to survive in the environment and food products. Although some aspects of the heat stress response in Campylobacter jejuni are already known, information about the stress response in other Campylobacter species are still scarce. In this study, the stress response of Campylobacter coli and Campylobacter lari to elevated temperatures (46°C) was investigated by survival assays and whole transcriptome analysis. None of the strains survived at 46°C for more than 8 h and approximately 20% of the genes of C. coli RM2228 and C. lari RM2100 were differentially expressed. The transcriptomic profiles showed enhanced gene expression of several chaperones like dnaK, groES, groEL, and clpB in both strains, indicating a general involvement in the heat stress response within the Campylobacter species. However, the pronounced differences in the expression pattern between C. coli and C. lari suggest that stress response mechanisms described for one Campylobacter species might be not necessarily transferable to other Campylobacter species.
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Affiliation(s)
- Carolin Riedel
- Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
| | - Konrad U Förstner
- Chair of Molecular Infection Biology II, Institute of Molecular Infection Biology, Julius Maximilian University of Würzburg, Würzburg, Germany
- ZB MED - Information Centre for Life Sciences, Köln, Germany
- Institute of Information Science, Faculty of Information Science and Communication Studies, TH Köln (University of Applied Sciences), Köln, Germany
| | - Christoph Püning
- Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
| | - Thomas Alter
- Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
| | - Cynthia M Sharma
- Chair of Molecular Infection Biology II, Institute of Molecular Infection Biology, Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Greta Gölz
- Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
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11
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Li X, Ren F, Cai G, Huang P, Chai Q, Gundogdu O, Jiao X, Huang J. Investigating the Role of FlhF Identifies Novel Interactions With Genes Involved in Flagellar Synthesis in Campylobacter jejuni. Front Microbiol 2020; 11:460. [PMID: 32265885 PMCID: PMC7105676 DOI: 10.3389/fmicb.2020.00460] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 03/04/2020] [Indexed: 12/15/2022] Open
Abstract
FlhF is a key protein required for complete flagellar synthesis, and its deletion results in the complete absence of a flagella and thus motility in Campylobacter jejuni. However, the specific mechanism still remains unknown. In this study, RNA-Seq, EMSAs, ChIP-qPCR and β-Galactosidase assays were performed to elucidate the novel interactions between FlhF and genes involved in flagellar synthesis. Results showed that FlhF has an overall influence on the transcription of flagellar genes with an flhF mutant displaying down-regulation of most flagellar related genes. FlhF can directly bind to the flgI promoter to regulate its expression, which has significant expression change in an flhF mutant. The possible binding site of FlhF to the flgI promoter was explored by continuously narrowing the flgI promoter region and performing further point mutations. Meanwhile, FlhF can directly bind to the promoters of rpoD, flgS, and fliA encoding early flagellin regulators, thereby directly or indirectly regulating the synthesis of class I, II, and III flagellar genes, respectively. Collectively, this study demonstrates that FlhF may directly regulate the transcription of flagellar genes by binding to their promoters as a transcriptional regulator, which will be helpful in understanding the mechanism of FlhF in flagellar biosynthetic and bacterial flagellation in general.
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Affiliation(s)
- Xiaofei Li
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Fangzhe Ren
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Guoqiang Cai
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou, China
| | - Pingyu Huang
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou, China
| | - Qinwen Chai
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou, China
| | - Ozan Gundogdu
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Xinan Jiao
- Joint International Research Laboratory of Agriculture and Agri-product Safety, Ministry of Education of China, Yangzhou, China
| | - Jinlin Huang
- Joint International Research Laboratory of Agriculture and Agri-product Safety, Ministry of Education of China, Yangzhou, China
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12
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Evaluation of commercial antimicrobials against stress-adapted Campylobacter jejuni on broiler wings by using immersion and electrostatic spray and an economic feasibility analysis. Food Control 2019. [DOI: 10.1016/j.foodcont.2019.04.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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Pleiotropic Effects of c-di-GMP Content in Pseudomonas syringae. Appl Environ Microbiol 2019; 85:AEM.00152-19. [PMID: 30850427 PMCID: PMC6498148 DOI: 10.1128/aem.00152-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 02/27/2019] [Indexed: 12/27/2022] Open
Abstract
The present work comprehensively analyzed the transcriptome and phenotypes that were regulated by c-di-GMP in P. syringae. Given that the majority of diguanylate cyclases and phosphodiesterases have not been characterized in P. syringae, this work provided a very useful database for the future study on regulatory mechanism (especially its relationship with T3SS) of c-di-GMP in P. syringae. In particular, we identified three promoters that were sensitive to elevated c-di-GMP levels and inserted them into luciferase-based reporters that effectively respond to intracellular levels of c-di-GMP in P. syringae, which could be used as an economic and efficient way to measure relative c-di-GMP levels in vivo in the future. Although the ubiquitous bacterial secondary messenger cyclic diguanylate (c-di-GMP) has important cellular functions in a wide range of bacteria, its function in the model plant pathogen Pseudomonas syringae remains largely elusive. To this end, we overexpressed Escherichia coli diguanylate cyclase (YedQ) and phosphodiesterase (YhjH) in P. syringae, resulting in high and low in vivo levels of c-di-GMP, respectively. Via genome-wide RNA sequencing of these two strains, we found that c-di-GMP regulates (i) fliN, fliE, and flhA, which are associated with flagellar assembly; (ii) alg8 and alg44, which are related to the exopolysaccharide biosynthesis pathway; (iii) pvdE, pvdP, and pvsA, which are associated with the siderophore biosynthesis pathway; and (iv) sodA, which encodes a superoxide dismutase. In particular, we identified three promoters that are sensitive to elevated levels of c-di-GMP and inserted them into luciferase-based reporters that respond effectively to the c-di-GMP levels in P. syringae; these promoters could be useful in the measurement of in vivo levels of c-di-GMP in real time. Further phenotypic assays validated the RNA sequencing (RNA-seq) results and confirmed the effect on c-di-GMP-associated pathways, such as repressing the type III secretion system (T3SS) and motility while inducing biofilm production, siderophore production, and oxidative stress resistance. Taken together, these results demonstrate that c-di-GMP regulates the virulence and stress response in P. syringae, which suggests that tuning its level could be a new strategy to protect plants from attacks by this pathogen. IMPORTANCE The present work comprehensively analyzed the transcriptome and phenotypes that were regulated by c-di-GMP in P. syringae. Given that the majority of diguanylate cyclases and phosphodiesterases have not been characterized in P. syringae, this work provided a very useful database for the future study on regulatory mechanism (especially its relationship with T3SS) of c-di-GMP in P. syringae. In particular, we identified three promoters that were sensitive to elevated c-di-GMP levels and inserted them into luciferase-based reporters that effectively respond to intracellular levels of c-di-GMP in P. syringae, which could be used as an economic and efficient way to measure relative c-di-GMP levels in vivo in the future.
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14
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Kovács JK, Felső P, Horváth G, Schmidt J, Dorn Á, Ábrahám H, Cox A, Márk L, Emődy L, Kovács T, Schneider G. Stress Response and Virulence Potential Modulating Effect of Peppermint Essential Oil in Campylobacter jejuni. BIOMED RESEARCH INTERNATIONAL 2019; 2019:2971741. [PMID: 30719441 PMCID: PMC6335803 DOI: 10.1155/2019/2971741] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/14/2018] [Indexed: 12/12/2022]
Abstract
Campylobacter jejuni is one of the most common food-borne bacteria that causes gastrointestinal symptoms. In the present study we have investigated the molecular basis of the anti-Campylobacter effect of peppermint essential oil (PEO), one of the oldest EO used to treat gastrointestinal diseases. Transcriptomic, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and proteomic, two-dimensional polyacryl amid gel electrophoresis (2D-PAGE) methods have revealed that, in the presence of a sublethal concentration of PEO, the expression of several virulence-associated genes was decreased (cheY 0.84x; flhB 0.79x; flgE 0.205x; cadF 0.08x; wlaB 0.89x; porA 0.25x; cbf2 4.3x) while impaired motility was revealed with a functional analysis. Scanning electron micrographs of the exposed cells showed that, unlike in the presence of other stresses, the originally curved C. jejuni cells straightened upon PEO exposure. Gaining insight into the molecular background of this stress response, we have revealed that in the presence of PEO C. jejuni dominantly exerts a general stress response that elevates the expression of general stress genes like dnaK, groEL, groES (10.41x, 3.63x, and 4.77x). The most important genes dps, sodB, and katA involved in oxidative stress responses showed however moderate transcriptional elevations (1,58x, 1,55x, and 1,85x).
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Affiliation(s)
- J. K. Kovács
- Department of Medical Microbiology and Immunology, University of Pécs Medical School, Hungary
| | - P. Felső
- Department of Medical Microbiology and Immunology, University of Pécs Medical School, Hungary
| | - Gy. Horváth
- Department of Pharmacognosy, University of Pécs Medical School, Hungary
| | - J. Schmidt
- Department of Biochemistry and Medical Chemistry, University of Pécs Medical School, Hungary
| | - Á. Dorn
- Department of Medical Microbiology and Immunology, University of Pécs Medical School, Hungary
| | - H. Ábrahám
- Department of Medical Biology and Central Electron Microscope Laboratory, University of Pécs Medical School, Hungary
| | - A. Cox
- Department of Biotechnology, Nanophagetherapy Center, Enviroinvest Corporation, Pécs, Hungary
| | - L. Márk
- Department of Biochemistry and Medical Chemistry, University of Pécs Medical School, Hungary
| | - L. Emődy
- Department of Medical Microbiology and Immunology, University of Pécs Medical School, Hungary
- Veterinary Medical Research Institute, Hungarian Academy of Sciences, Budapest, Hungary
| | - T. Kovács
- Department of Biotechnology, Nanophagetherapy Center, Enviroinvest Corporation, Pécs, Hungary
| | - Gy. Schneider
- Department of Medical Microbiology and Immunology, University of Pécs Medical School, Hungary
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15
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Kim S, Jeong J, Lee H, Lee J, Lee S, Ha J, Choi Y, Yoon Y, Choi KH. Kinetic Behavior of Campylobacter jejuni in Beef Tartare at Cold Temperatures and Transcriptomes Related to Its Survival. J Food Prot 2017; 80:2127-2131. [PMID: 29166177 DOI: 10.4315/0362-028x.jfp-17-236] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study was conducted to examine the kinetic behavior of Campylobacter jejuni in raw beef tartare by using mathematical models and to identify genes related to C. jejuni survival at cold temperatures. C. jejuni was inoculated onto beef tartare samples, stored at 4, 10, 15, 25, and 30°C, plated on modified charcoal-cefoperazone-deoxycholate agar, and enumerated. The survival data was fitted to the Weibull model to calculate delta (δ), which is the time required for the first 1-log reduction of the cells. The Davey model was then fitted to the δ to evaluate the effect of temperature. To evaluate the performance of the developed model, the root mean square error (RMSE) was calculated by comparing the observed data with the predicted data. The mRNA was extracted from samples stored at 4 and 30°C under aerobic and anaerobic conditions, and the expression of oxidative stress response and stress response genes was evaluated. C. jejuni survived in beef tartare longer at 4°C (δ = 657.1 ± 79.6 min) than at other temperatures (9.7 ± 11.2 to 465.7 ± 139.3°C) even under aerobic conditions. The RMSE (0.475) suggested that the developed model was appropriate to describe the kinetic behavior of C. jejuni. Quantitative real-time PCR results revealed that oxidative stress and stress response genes were related to C. jejuni survival at cold temperatures, even under aerobic conditions. These results indicate that the model will be useful for describing the kinetic behavior of C. jejuni in beef tartare and that this pathogen can survive at cold temperatures because of the expression of the sodB, katA, and clpP genes.
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Affiliation(s)
- Sejeong Kim
- 1 Department of Food and Nutrition, Sookmyung Women's University, and Risk Analysis Research Center, Seoul 04310, Korea; and
| | - Jiyeon Jeong
- 1 Department of Food and Nutrition, Sookmyung Women's University, and Risk Analysis Research Center, Seoul 04310, Korea; and
| | - Heeyoung Lee
- 1 Department of Food and Nutrition, Sookmyung Women's University, and Risk Analysis Research Center, Seoul 04310, Korea; and
| | - Jeeyeon Lee
- 1 Department of Food and Nutrition, Sookmyung Women's University, and Risk Analysis Research Center, Seoul 04310, Korea; and
| | - Soomin Lee
- 1 Department of Food and Nutrition, Sookmyung Women's University, and Risk Analysis Research Center, Seoul 04310, Korea; and
| | - Jimyeong Ha
- 1 Department of Food and Nutrition, Sookmyung Women's University, and Risk Analysis Research Center, Seoul 04310, Korea; and
| | - Yukyoung Choi
- 1 Department of Food and Nutrition, Sookmyung Women's University, and Risk Analysis Research Center, Seoul 04310, Korea; and
| | - Yohan Yoon
- 1 Department of Food and Nutrition, Sookmyung Women's University, and Risk Analysis Research Center, Seoul 04310, Korea; and
| | - Kyoung-Hee Choi
- 2 Department of Oral Microbiology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538, Korea
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16
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Trigui H, Lee K, Thibodeau A, Lévesque S, Mendis N, Fravalo P, Letellier A, Faucher SP. Phenotypic and Transcriptomic Responses of Campylobacter jejuni Suspended in an Artificial Freshwater Medium. Front Microbiol 2017; 8:1781. [PMID: 28979243 PMCID: PMC5611540 DOI: 10.3389/fmicb.2017.01781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/01/2017] [Indexed: 12/24/2022] Open
Abstract
Campylobacter jejuni is the leading cause of campylobacteriosis in the developed world. Although most cases are caused by consumption of contaminated meat, a significant proportion is linked to ingestion of contaminated water. The differences between C. jejuni strains originating from food products and those isolated from water are poorly understood. Working under the hypothesis that water-borne C. jejuni strains are better equipped at surviving the nutrient-poor aquatic environment than food-borne strains, the present study aims to characterize these differences using outbreak strains 81116 and 81-176. Strain 81116 caused a campylobacteriosis outbreak linked to consumption of water, while strain 81-176 was linked to consumption of raw milk. CFU counts and viability assays showed that 81116 survives better than 81-176 at 4°C in a defined freshwater medium (Fraquil). Moreover, 81116 was significantly more resistant to oxidative stress and bile salt than strain 81-176 in Fraquil. To better understand the genetic response of 81116 to water, a transcriptomic profiling study was undertaken using microarrays. Compared to rich broth, strain 81116 represses genes involved in amino acid uptake and metabolism, as well as genes involved in costly biosynthetic processes such as replication, translation, flagellum synthesis and virulence in response to Fraquil. In accordance with the observed increase in stress resistance in Fraquil, 81116 induces genes involved in resistance to oxidative stress and bile salt. Interestingly, genes responsible for cell wall synthesis were also induced upon Fraquil exposure. Finally, twelve unique genes were expressed in Fraquil; however, analysis of their distribution in animal and water isolates showed that they are not uniquely and ubiquitously present in water isolates, and thus, unlikely to play a major role in adaptation to water. Our results show that some C. jejuni strains are more resilient than others, thereby challenging current water management practices. The response of 81116 to Fraquil serves as a starting point to understand the adaptation of C. jejuni to water and its subsequent transmission.
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Affiliation(s)
- Hana Trigui
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-BellevueQC, Canada
| | - Kristen Lee
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-BellevueQC, Canada
| | - Alexandre Thibodeau
- Research Chair in Meat Safety, Department of Pathology and Microbiology, University of Montreal, Saint-HyacintheQC, Canada
| | - Simon Lévesque
- Laboratoire de Santé Publique du Québec (LSPQ)/Institut National de Santé Publique du Québec, Sainte-Anne-de-BellevueQC, Canada
| | - Nilmini Mendis
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-BellevueQC, Canada
| | - Philippe Fravalo
- Research Chair in Meat Safety, Department of Pathology and Microbiology, University of Montreal, Saint-HyacintheQC, Canada
| | - Ann Letellier
- Research Chair in Meat Safety, Department of Pathology and Microbiology, University of Montreal, Saint-HyacintheQC, Canada
| | - Sébastien P. Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-BellevueQC, Canada
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17
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Xiao M, Zhu X, Xu H, Tang J, Liu R, Bi C, Fan F, Zhang X. A novel point mutation in RpoB improves osmotolerance and succinic acid production in Escherichia coli. BMC Biotechnol 2017; 17:10. [PMID: 28193207 PMCID: PMC5307762 DOI: 10.1186/s12896-017-0337-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 02/10/2017] [Indexed: 11/29/2022] Open
Abstract
Background Escherichia coli suffer from osmotic stress during succinic acid (SA) production, which reduces the performance of this microbial factory. Results Here, we report that a point mutation leading to a single amino acid change (D654Y) within the β-subunit of DNA-dependent RNA polymerase (RpoB) significantly improved the osmotolerance of E. coli. Importation of the D654Y mutation of RpoB into the parental strain, Suc-T110, increased cell growth and SA production by more than 40% compared to that of the control under high glucose osmolality. The transcriptome profile, determined by RNA-sequencing, showed two distinct stress responses elicited by the mutated RpoB that counterbalanced the osmotic stress. Under non-stressed conditions, genes involved in the synthesis and transport of compatible solutes such as glycine-betaine, glutamate or proline were upregulated even without osmotic stimulation, suggesting a “pre-defense” mechanism maybe formed in the rpoB mutant. Under osmotic stressed conditions, genes encoding diverse sugar transporters, which should be down-regulated in the presence of high osmotic pressure, were derepressed in the rpoB mutant. Additional genetic experiments showed that enhancing the expression of the mal regulon, especially for genes that encode the glycoporin LamB and maltose transporter, contributed to the osmotolerance phenotype. Conclusions The D654Y single amino acid substitution in RpoB rendered E. coli cells resistant to osmotic stress, probably due to improved cell growth and viability via enhanced sugar uptake under stressed conditions, and activated a potential “pre-defense” mechanism under non-stressed conditions. The findings of this work will be useful for bacterial host improvement to enhance its resistance to osmotic stress and facilitate bio-based organic acids production. Electronic supplementary material The online version of this article (doi:10.1186/s12896-017-0337-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mengyong Xiao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xinna Zhu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Hongtao Xu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Jinlei Tang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Ru Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Changhao Bi
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China
| | - Feiyu Fan
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China. .,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China.
| | - Xueli Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China. .,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, 32 West 7th Ave, Tianjin Airport Economic Park, Tianjin, 300308, China.
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18
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The EbpA-RpoN Regulatory Pathway of the Pathogen Leptospira interrogans Is Essential for Survival in the Environment. Appl Environ Microbiol 2017; 83:AEM.02377-16. [PMID: 27864172 DOI: 10.1128/aem.02377-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/14/2016] [Indexed: 01/01/2023] Open
Abstract
Leptospira interrogans is the agent of leptospirosis, a reemerging zoonotic disease. It is transmitted to humans through environmental surface waters contaminated by the urine of mammals chronically infected by pathogenic strains able to survive in water for long periods. Little is known about the regulatory pathways underlying environmental sensing and host adaptation of L. interrogans during its enzootic cycle. This study identifies the EbpA-RpoN regulatory pathway in L. interrogans In this pathway, EbpA, a σ54 activator and putative prokaryotic enhancer-binding protein (EBP), and the alternative sigma factor RpoN (σ54) control expression of at least three genes, encoding AmtB (an ammonium transport protein) and two proteins of unknown function. Electrophoresis mobility shift assay demonstrated that recombinant RpoN and EbpA bind to the promoter region and upstream of these three identified genes, respectively. Genetic disruption of ebpA in L. interrogans serovar Manilae virtually abolished expression of the three genes, including amtB in two independent ebpA mutants. Complementation of the ebpA mutant restored expression of these genes. Intraperitoneal inoculation of gerbils with the ebpA mutant did not affect mortality. However, the ebpA mutant had decreased cell length in vitro and had a significantly lowered cell density at stationary phase when grown with l-alanine as the sole nitrogen source. Furthermore, the ebpA mutant has dramatically reduced long-term survival ability in water. Together, these studies identify a regulatory pathway, the EbpA-RpoN pathway, that plays an important role in the zoonotic cycle of L. interrogans IMPORTANCE: Leptospirosis is a reemerging disease with global importance. However, our understanding of gene regulation of the spirochetal pathogen Leptospira interrogans is still in its infancy, largely due to the lack of robust tools for genetic manipulation of this spirochete. Little is known about how the pathogen achieves its long-term survival in the aquatic environment. By utilizing bioinformatic, genetic, and biochemical methods, we discovered a regulatory pathway in L. interrogans, the EbpA-RpoN pathway, and demonstrated that this pathway plays an important role in environmental survival of this pathogen.
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19
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The response of foodborne pathogens to osmotic and desiccation stresses in the food chain. Int J Food Microbiol 2016; 221:37-53. [PMID: 26803272 DOI: 10.1016/j.ijfoodmicro.2015.12.014] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 12/22/2015] [Accepted: 12/30/2015] [Indexed: 12/24/2022]
Abstract
In combination with other strategies, hyperosmolarity and desiccation are frequently used by the food processing industry as a means to prevent bacterial proliferation, and particularly that of foodborne pathogens, in food products. However, it is increasingly observed that bacteria, including human pathogens, encode mechanisms to survive and withstand these stresses. This review provides an overview of the mechanisms employed by Salmonella spp., Shiga toxin producing E. coli, Cronobacter spp., Listeria monocytogenes and Campylobacter spp. to tolerate osmotic and desiccation stresses and identifies gaps in knowledge which need to be addressed to ensure the safety of low water activity and desiccated food products.
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20
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Zeng X, Chen XS, Gao Y, Ren XD, Wang L, Mao ZG. Continuously high reactive oxygen species generation decreased the specific ϵ-poly- l -lysine formation rate in fed-batch fermentation using glucose and glycerol as a mixed carbon source. Process Biochem 2015. [DOI: 10.1016/j.procbio.2015.09.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Hayrapetyan H, Tempelaars M, Nierop Groot M, Abee T. Bacillus cereus ATCC 14579 RpoN (Sigma 54) Is a Pleiotropic Regulator of Growth, Carbohydrate Metabolism, Motility, Biofilm Formation and Toxin Production. PLoS One 2015; 10:e0134872. [PMID: 26241851 PMCID: PMC4524646 DOI: 10.1371/journal.pone.0134872] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 07/14/2015] [Indexed: 12/16/2022] Open
Abstract
Sigma 54 is a transcriptional regulator predicted to play a role in physical interaction of bacteria with their environment, including virulence and biofilm formation. In order to study the role of Sigma 54 in Bacillus cereus, a comparative transcriptome and phenotypic study was performed using B. cereus ATCC 14579 WT, a markerless rpoN deletion mutant, and its complemented strain. The mutant was impaired in many different cellular functions including low temperature and anaerobic growth, carbohydrate metabolism, sporulation and toxin production. Additionally, the mutant showed lack of motility and biofilm formation at air-liquid interphase, and this correlated with absence of flagella, as flagella staining showed only WT and complemented strain to be highly flagellated. Comparative transcriptome analysis of cells harvested at selected time points during growth in aerated and static conditions in BHI revealed large differences in gene expression associated with loss of phenotypes, including significant down regulation of genes in the mutant encoding enzymes involved in degradation of branched chain amino acids, carbohydrate transport and metabolism, flagella synthesis and virulence factors. Our study provides evidence for a pleiotropic role of Sigma 54 in B. cereus supporting its adaptive response and survival in a range of conditions and environments.
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Affiliation(s)
- Hasmik Hayrapetyan
- Laboratory of Food Microbiology, Bornse Weilanden 9, 6708 WG Wageningen University, Wageningen, The Netherlands
- Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA, Wageningen, The Netherlands
| | - Marcel Tempelaars
- Laboratory of Food Microbiology, Bornse Weilanden 9, 6708 WG Wageningen University, Wageningen, The Netherlands
- Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA, Wageningen, The Netherlands
| | - Masja Nierop Groot
- Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA, Wageningen, The Netherlands
- Food and Biobased research, Wageningen UR, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Tjakko Abee
- Laboratory of Food Microbiology, Bornse Weilanden 9, 6708 WG Wageningen University, Wageningen, The Netherlands
- Top Institute of Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA, Wageningen, The Netherlands
- * E-mail:
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22
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Kim JC, Oh E, Kim J, Jeon B. Regulation of oxidative stress resistance in Campylobacter jejuni, a microaerophilic foodborne pathogen. Front Microbiol 2015; 6:751. [PMID: 26284041 PMCID: PMC4518328 DOI: 10.3389/fmicb.2015.00751] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/08/2015] [Indexed: 12/31/2022] Open
Abstract
Campylobacter jejuni is one of the leading bacterial causes of human gastroenteritis. Due to the increasing rates of human campylobacteriosis, C. jejuni is considered as a serious public health concern worldwide. C. jejuni is a microaerophilic, fastidious bacterium. C. jejuni must overcome a wide range of stress conditions during foodborne transmission to humans, such as food preservation and processing conditions, and even in infection of the gastrointestinal tracts of humans. Particularly, this microaerophilic foodborne pathogen must survive in the atmospheric conditions prior to the initiation of infection. C. jejuni possesses unique regulatory mechanisms for oxidative stress resistance. Lacking OxyR and SoxRS that are highly conserved in other Gram-negative foodborne pathogens, C. jejuni modulates the expression of genes involved in oxidative stress resistance mainly via the peroxide resistance regulator and Campylobacter oxidative stress regulator. Based on recent findings of ours and others, in this review, we described how C. jejuni regulates the expression of oxidative stress defense.
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Affiliation(s)
| | | | | | - Byeonghwa Jeon
- School of Public Health, University of Alberta, EdmontonAB, Canada
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Handley RA, Mulholland F, Reuter M, Ramachandran VK, Musk H, Clissold L, Le Brun NE, van Vliet AHM. PerR controls oxidative stress defence and aerotolerance but not motility-associated phenotypes of Campylobacter jejuni. MICROBIOLOGY-SGM 2015; 161:1524-36. [PMID: 25968890 DOI: 10.1099/mic.0.000109] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
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.
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Affiliation(s)
- Rebecca A Handley
- 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
| | - Francis Mulholland
- 1 Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK
| | - Mark Reuter
- 1 Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK
| | | | - Heather Musk
- 4 The Genome Analysis Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Leah Clissold
- 4 The Genome Analysis Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Nick E Le Brun
- 2 Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Arnoud H M van Vliet
- 1 Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK
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Flagella-mediated adhesion and extracellular DNA release contribute to biofilm formation and stress tolerance of Campylobacter jejuni. PLoS One 2014; 9:e106063. [PMID: 25166748 PMCID: PMC4148357 DOI: 10.1371/journal.pone.0106063] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 07/31/2014] [Indexed: 11/19/2022] Open
Abstract
Campylobacter jejuni is a leading cause of foodbourne gastroenteritis, despite fragile behaviour under standard laboratory conditions. In the environment, C. jejuni may survive within biofilms, which can impart resident bacteria with enhanced stress tolerance compared to their planktonic counterparts. While C. jejuni forms biofilms in vitro and in the wild, it had not been confirmed that this lifestyle confers stress tolerance. Moreover, little is understood about molecular mechanisms of biofilm formation in this pathogen. We previously found that a ΔcprS mutant, which carries a deletion in the sensor kinase of the CprRS two-component system, forms enhanced biofilms. Biofilms were also enhanced by the bile salt deoxycholate and contained extracellular DNA. Through more in-depth analysis of ΔcprS and WT under conditions that promote or inhibit biofilms, we sought to further define this lifestyle for C. jejuni. Epistasis experiments with ΔcprS and flagellar mutations (ΔflhA, ΔpflA) suggested that initiation is mediated by flagellum-mediated adherence, a process which was kinetically enhanced by motility. Lysis was also observed, especially under biofilm-enhancing conditions. Microscopy suggested adherence was followed by release of eDNA, which was required for biofilm maturation. Importantly, inhibiting biofilm formation by removal of eDNA with DNase decreased stress tolerance. This work suggests the biofilm lifestyle provides C. jejuni with resilience that has not been apparent from observation of planktonic bacteria during routine laboratory culture, and provides a framework for subsequent molecular studies of C. jejuni biofilms.
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Le MT, Porcelli I, Weight CM, Gaskin DJH, Carding SR, van Vliet AHM. Acid-shock of Campylobacter jejuni induces flagellar gene expression and host cell invasion. Eur J Microbiol Immunol (Bp) 2012; 2:12-9. [PMID: 24611116 DOI: 10.1556/eujmi.2.2012.1.3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 01/14/2012] [Indexed: 11/19/2022] Open
Abstract
The bacterial pathogen Campylobacter jejuni is the leading cause of foodborne gastroenteritis in the developed world, with the organism being transmitted by ingestion of contaminated and undercooked poultry. Exposure to acid is an inevitable stressor for C. jejuni during gastric passage, yet the effect of low pH on C. jejuni virulence is still poorly understood. Here, we investigate the effect of acid-shock on C. jejuni viability, gene expression and host-cell invasion. C. jejuni strain NCTC 11168 survived acid exposure at pH 3.5 and above for up to 30 min without a drop in viability, and this exposure induced the expression of flagellar genes transcribed from σ(54)-dependent promoters. Furthermore, acid-shock resulted in increased C. jejuni invasion of m-ICcl2 mouse small intestine crypt cells grown on transwells, but not when the cells were grown on flat-bottomed wells. This suggests that C. jejuni might be invading intestinal epithelial cells at the basolateral side, possibly after paracellular passage. We hypothesize that acid-shock prior to intestinal entry may serve as a signal that primes C. jejuni to express its virulence gene repertoire including flagellar motility genes, but this requires further study in the context of an appropriate colonization or disease model.
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Szymanski CM, Gaynor E. How a sugary bug gets through the day: recent developments in understanding fundamental processes impacting Campylobacter jejuni pathogenesis. Gut Microbes 2012; 3:135-44. [PMID: 22555465 PMCID: PMC3370946 DOI: 10.4161/gmic.19488] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Campylobacter jejuni is a highly prevalent yet fastidious bacterial pathogen that poses a significant health burden worldwide. Lacking many hallmark virulence factors, it is becoming increasingly clear that C. jejuni pathogenesis involves different strategies compared with other well-characterized enteric organisms. This includes the involvement of basic biological processes and cell envelope glycans in a number of aspects related to pathogenesis. The past few years have seen significant progress in the understanding of these pathways and how they relate to C. jejuni fundamental biology, stress survival, colonization, and virulence attributes. This review focuses on recent studies in three general areas where "pathogenesis" and "basic biology" overlap: physiology, stress responses and glycobiology.
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Affiliation(s)
- Christine M. Szymanski
- Alberta Glycomics Centre and Department of Biological Sciences; University of Alberta; Edmonton, Canada,Correspondence to: Christine M. Szymanski, or Erin Gaynor,
| | - Erin Gaynor
- Department of Microbiology and Immunology; University of British Columbia; Vancouver, Canada,Correspondence to: Christine M. Szymanski, or Erin Gaynor,
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