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Wang F, Sun H, Kang C, Yan J, Chen J, Feng X, Yang B. Genomic island-encoded regulatory proteins in enterohemorrhagic Escherichia coli O157:H7. Virulence 2024; 15:2313407. [PMID: 38357901 PMCID: PMC10877973 DOI: 10.1080/21505594.2024.2313407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/23/2024] [Indexed: 02/16/2024] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is an important zoonotic pathogen that is a major cause of foodborne diseases in most developed and developing countries and can cause uncomplicated diarrhoea, haemorrhagic colitis, and haemolytic uraemic syndrome. O islands (OIs), which are unique genomic islands in EHEC O157:H7, are composed of 177 isolated genomic features and harbour 26% of the total genes that are absent in the non-pathogenic E. coli K-12 genome. In the last twenty years, many OI-encoded proteins have been characterized, including proteins regulating virulence, motility, and acid resistance. Given the critical role of regulatory proteins in the systematic and hierarchical regulation of bacterial biological processes, this review summarizes the OI-encoded regulatory proteins in EHEC O157:H7 characterized to date, emphasizing OI-encoded regulatory proteins for bacterial virulence, motility, and acid resistance. This summary will be significant for further exploration and understanding of the virulence and pathogenesis of EHEC O157:H7.
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Affiliation(s)
- Fang Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- Intensive Care Unit, Shenzhen Institute of Translational Medicine, Health Science Center, The First Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Hongmin Sun
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
| | - Chenbo Kang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
| | - Jun Yan
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
| | - Jingnan Chen
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
| | - Xuequan Feng
- Tianjin First Central Hospital, Nankai University, Tianjin, China
| | - Bin Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
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2
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Han X, Fu L, Yu J, Li K, Deng Z, Shu R, Wang D, You J, Zeng EY. Effects of erythromycin on biofilm formation and resistance mutation of Escherichia coli on pristine and UV-aged polystyrene microplastics. WATER RESEARCH 2024; 256:121628. [PMID: 38677035 DOI: 10.1016/j.watres.2024.121628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/23/2024] [Accepted: 04/16/2024] [Indexed: 04/29/2024]
Abstract
Microplastics (MPs) and antibiotics co-occur widely in the environment and pose combined risk to microbial communities. The present study investigated the effects of erythromycin on biofilm formation and resistance mutation of a model bacterium, E. coli, on the surface of pristine and UV-aged polystyrene (PS) MPs sized 1-2 mm. The properties of UV-aged PS were significantly altered compared to pristine PS, with notable increases in specific surface area, carbonyl index, hydrophilicity, and hydroxyl radical content. Importantly, the adsorption capacity of UV-aged PS towards erythromycin was approximately 8-fold higher than that of pristine PS. Biofilms colonizing on UV-aged PS had a greater cell count (5.6 × 108 CFU mg-1) and a higher frequency of resistance mutation (1.0 × 10-7) than those on pristine PS (1.4 × 108 CFU mg-1 and 1.4 × 10-8, respectively). Moreover, erythromycin at 0.1 and 1.0 mg L-1 significantly (p < 0.05) promoted the formation and resistance mutation of biofilm on both pristine and UV-aged PS. DNA sequencing results confirmed that the biofilm resistance was attributed to point mutations in rpoB segment of the bacterial genome. qPCR results demonstrated that both UV aging and erythromycin repressed the expression levels of a global regulator rpoS in biofilm bacteria, as well as two DNA mismatch repair genes mutS and uvrD, which was likely to contribute to increased resistance mutation frequency.
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Affiliation(s)
- Xiaofeng Han
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and Center for Environmental Microplastics Studies, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 511443, China
| | - Long Fu
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and Center for Environmental Microplastics Studies, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 511443, China
| | - Jing Yu
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and Center for Environmental Microplastics Studies, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 511443, China
| | - Kunting Li
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and Center for Environmental Microplastics Studies, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 511443, China
| | | | | | - Dali Wang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and Center for Environmental Microplastics Studies, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 511443, China.
| | - Jing You
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and Center for Environmental Microplastics Studies, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 511443, China
| | - Eddy Y Zeng
- Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters (Ministry of Education), School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
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3
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Petrova O, Semenova E, Parfirova O, Tsers I, Gogoleva N, Gogolev Y, Nikolaichik Y, Gorshkov V. RpoS-Regulated Genes and Phenotypes in the Phytopathogenic Bacterium Pectobacterium atrosepticum. Int J Mol Sci 2023; 24:17348. [PMID: 38139177 PMCID: PMC10743746 DOI: 10.3390/ijms242417348] [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: 11/07/2023] [Revised: 12/04/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
The alternative sigma factor RpoS is considered to be one of the major regulators providing stress resistance and cross-protection in bacteria. In phytopathogenic bacteria, the effects of RpoS have not been analyzed with regard to cross-protection, and genes whose expression is directly or indirectly controlled by RpoS have not been determined at the whole-transcriptome level. Our study aimed to determine RpoS-regulated genes and phenotypes in the phytopathogenic bacterium Pectobacterium atrosepticum. Knockout of the rpoS gene in P. atrosepticum affected the long-term starvation response, cross-protection, and virulence toward plants with enhanced immune status. The whole-transcriptome profiles of the wild-type P. atrosepticum strain and its ΔrpoS mutant were compared under different experimental conditions, and functional gene groups whose expression was affected by RpoS were determined. The RpoS promoter motif was inferred within the promoter regions of the genes affected by rpoS deletion, and the P. atrosepticum RpoS regulon was predicted. Based on RpoS-controlled phenotypes, transcriptome profiles, and RpoS regulon composition, the regulatory role of RpoS in P. atrosepticum is discussed.
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Affiliation(s)
- Olga Petrova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Elizaveta Semenova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Olga Parfirova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Ivan Tsers
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Natalia Gogoleva
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
| | - Yuri Gogolev
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia
| | - Yevgeny Nikolaichik
- Department of Molecular Biology, Belarusian State University, 220030 Minsk, Belarus;
| | - Vladimir Gorshkov
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia; (O.P.); (E.S.); (O.P.); (I.T.); (N.G.); (Y.G.)
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia
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Detert K, Währer J, Nieselt K, Schmidt H. Broad time-dependent transcriptional activity of metabolic genes of E. coli O104:H4 strain C227/11Φcu in a soil microenvironment at low temperature. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:582-596. [PMID: 37644642 PMCID: PMC10667640 DOI: 10.1111/1758-2229.13198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023]
Abstract
In the current study, metabolic genes and networks that influence the persistence of pathogenic Escherichia coli O104:H4 strain C227/11Φcu in agricultural soil microenvironments at low temperature were investigated. The strain was incubated in alluvial loam (AL) and total RNA was prepared from samples at time point 0, and after 1 and 4 weeks. Differential transcriptomic analysis was performed by RNA sequencing analysis and values obtained at weeks 1 and 4 were compared to those of time point 0. We found differential expression of more than 1500 genes for either time point comparison. The two lists of differentially expressed genes were then subjected to gene set enrichment of Gene Ontology terms. In total, 17 GO gene sets and 3 Pfam domains were found to be enriched after 1 week. After 4 weeks, 17 GO gene sets and 7 Pfam domains were statistically enriched. Especially stress response genes and genes of the primary metabolism were particularly affected at both time points. Genes and gene sets for uptake of carbohydrates, amino acids were strongly upregulated, indicating adjustment to a low nutrient environment. The results of this transcriptome analysis show that persistence of C227/11Φcu in soils is associated with a complex interplay of metabolic networks.
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Affiliation(s)
- Katharina Detert
- Department of Food Microbiology and Hygiene, Institute of Food Science and BiotechnologyUniversity of HohenheimStuttgartGermany
| | - Jonathan Währer
- Institute for Bioinformatics and Medical InformaticsUniversity of TübingenTübingenGermany
| | - Kay Nieselt
- Institute for Bioinformatics and Medical InformaticsUniversity of TübingenTübingenGermany
| | - Herbert Schmidt
- Department of Food Microbiology and Hygiene, Institute of Food Science and BiotechnologyUniversity of HohenheimStuttgartGermany
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5
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Yang S, Ma L, Xu X, Peng Q, Zhong H, Gong Y, Shi L, He M, Shi B, Qiao Y. Physiological and Transcriptomic Analyses of Escherichia coli Serotype O157:H7 in Response to Rhamnolipid Treatment. Microorganisms 2023; 11:2112. [PMID: 37630672 PMCID: PMC10459150 DOI: 10.3390/microorganisms11082112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/13/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
Rhamnolipid (RL) can inhibit biofilm formation of Escherichia coli O157:H7, but the associated mechanism remains unknown. We here conducted comparative physiological and transcriptomic analyses of cultures treated with RL and untreated cultures to elucidate a potential mechanism by which RL may inhibit biofilm formation in E. coli O157:H7. Anti-biofilm assays showed that over 70% of the E. coli O157:H7 biofilm formation capacity was inhibited by treatment with 0.25-1 mg/mL of RL. Cellular-level physiological analysis revealed that a high concentration of RL significantly reduced outer membrane hydrophobicity. E. coli cell membrane integrity and permeability were also significantly affected by RL due to an increase in the release of lipopolysaccharide (LPS) from the cell membrane. Furthermore, transcriptomic profiling showed 2601 differentially expressed genes (1344 up-regulated and 1257 down-regulated) in cells treated with RL compared to untreated cells. Functional enrichment analysis indicated that RL treatment up-regulated biosynthetic genes responsible for LPS synthesis, outer membrane protein synthesis, and flagellar assembly, and down-regulated genes required for poly-N-acetyl-glucosamine biosynthesis and genes present in the locus of enterocyte effacement pathogenicity island. In summary, RL treatment inhibited E. coli O157:H7 biofilm formation by modifying key outer membrane surface properties and expression levels of adhesion genes.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Bo Shi
- Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (S.Y.); (L.M.); (X.X.); (Q.P.); (H.Z.); (Y.G.); (L.S.); (M.H.)
| | - Yu Qiao
- Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (S.Y.); (L.M.); (X.X.); (Q.P.); (H.Z.); (Y.G.); (L.S.); (M.H.)
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6
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Holden ER, Yasir M, Turner AK, Wain J, Charles IG, Webber MA. Genome-wide analysis of genes involved in efflux function and regulation within Escherichia coli and Salmonella enterica serovar Typhimurium. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36745554 DOI: 10.1099/mic.0.001296] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The incidence of multidrug-resistant bacteria is increasing globally, with efflux pumps being a fundamental platform limiting drug access and synergizing with other mechanisms of resistance. Increased expression of efflux pumps is a key feature of most cells that are resistant to multiple antibiotics. Whilst expression of efflux genes can confer benefits, production of complex efflux systems is energetically costly and the expression of efflux is highly regulated, with cells balancing benefits against costs. This study used TraDIS-Xpress, a genome-wide transposon mutagenesis technology, to identify genes in Escherichia coli and Salmonella Typhimurium involved in drug efflux and its regulation. We exposed mutant libraries to the canonical efflux substrate acriflavine in the presence and absence of the efflux inhibitor phenylalanine-arginine β-naphthylamide. Comparisons between conditions identified efflux-specific and drug-specific responses. Known efflux-associated genes were easily identified, including acrAB, tolC, marRA, ramRA and soxRS, confirming the specificity of the response. Further genes encoding cell envelope maintenance enzymes and products involved with stringent response activation, DNA housekeeping, respiration and glutathione biosynthesis were also identified as affecting efflux activity in both species. This demonstrates the deep relationship between efflux regulation and other cellular regulatory networks. We identified a conserved set of pathways crucial for efflux activity in these experimental conditions, which expands the list of genes known to impact on efflux efficacy. Responses in both species were similar and we propose that these common results represent a core set of genes likely to be relevant to efflux control across the Enterobacteriaceae.
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Affiliation(s)
- Emma R Holden
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK
| | - Muhammad Yasir
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK
| | - A Keith Turner
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK
| | - John Wain
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK.,Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Ian G Charles
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK.,Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Mark A Webber
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk, NR4 7UQ, UK.,Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
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7
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Wang F, Yao T, Yang W, Wu P, Liu Y, Yang B. Protocol to detect nucleotide-protein interaction in vitro using a non-radioactive competitive electrophoretic mobility shift assay. STAR Protoc 2022; 3:101730. [PMID: 36181685 PMCID: PMC9530670 DOI: 10.1016/j.xpro.2022.101730] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/10/2022] [Accepted: 09/02/2022] [Indexed: 01/26/2023] Open
Abstract
Electrophoretic mobility shift assay (EMSA) is a classical and popular approach for DNA/RNA protein-binding affinity detection in vitro. This protocol describes a competitive EMSA assay using digoxigenin (DIG)-labeled probe, which solves the safety issues and limitations attributed to the short lifespan of the 32P-radiolabeled DNA probe. We detail steps for DNA probe preparation, protein-DNA mixture coincubation, EMSA, and competitive EMSA process. We optimize the standard DIG-ddUTP-labeling EMSA protocol to high sensitivity with reproducible results. For complete details on the use and execution of this protocol, please refer to Feng et al. (2022).
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Affiliation(s)
- Fang Wang
- Intensive Care Unit, Shenzhen Institute of Translational Medicine, Health Science Center, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518035, China
| | - Ting Yao
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, China
| | - Wen Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, China
| | - Pan Wu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, China
| | - Yutao Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, China
| | - Bin Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, China.
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Degradation of Exogenous Fatty Acids in Escherichia coli. Biomolecules 2022; 12:biom12081019. [PMID: 35892328 PMCID: PMC9329746 DOI: 10.3390/biom12081019] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/19/2022] [Accepted: 07/19/2022] [Indexed: 12/10/2022] Open
Abstract
Many bacteria possess all the machineries required to grow on fatty acids (FA) as a unique source of carbon and energy. FA degradation proceeds through the β-oxidation cycle that produces acetyl-CoA and reduced NADH and FADH cofactors. In addition to all the enzymes required for β-oxidation, FA degradation also depends on sophisticated systems for its genetic regulation and for FA transport. The fact that these machineries are conserved in bacteria suggests a crucial role in environmental conditions, especially for enterobacteria. Bacteria also possess specific enzymes required for the degradation of FAs from their environment, again showing the importance of this metabolism for bacterial adaptation. In this review, we mainly describe FA degradation in the Escherichia coli model, and along the way, we highlight and discuss important aspects of this metabolism that are still unclear. We do not detail exhaustively the diversity of the machineries found in other bacteria, but we mention them if they bring additional information or enlightenment on specific aspects.
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9
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Dong S, Liu X, Chen T, Zhou X, Li S, Fu S, Gong H. Mutation of rpoS is Beneficial for Suppressing Organic Acid Secretion During 1,3-Propandiol Biosynthesis in Klebsiella pneumoniae. Curr Microbiol 2022; 79:218. [PMID: 35704098 DOI: 10.1007/s00284-022-02901-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 05/09/2022] [Indexed: 11/25/2022]
Abstract
In this study, to reduce the formation of organic acid during 1,3-propanediol biosynthesis in Klebsiella pneumoniae, a method combining UV mutagenesis and high-throughput screening with pH color plates was employed to obtain K. pneumoniae mutants. When compared with the parent strain, the total organic acid formation by the mutant decreased, whereas 1,3-propanediol biosynthesis increased after 24 h anaerobic shake flask culture. Subsequently, genetic changes in the mutant were analyzed by whole-genome sequencing and verified by signal gene deletion. Mutation of the rpoS gene was confirmed to contribute to the regulation of organic acid synthesis in K. pneumoniae. Besides, rpoS deletion eliminated the formation of 2,3-butanediol, the main byproduct produced during 1,3-propanediol fermentation, indicating the role of rpoS in metabolic regulation in K. pneumoniae. Thus, a K. pneumoniae mutant was developed, which could produce lower organic acid during 1,3-propanediol fermentation due to an rpoS mutation in this study.
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Affiliation(s)
- Shufan Dong
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Xuxia Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Tianyu Chen
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Xiaoqin Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Shengming Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Shuilin Fu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Heng Gong
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
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Baptista ISC, Kandavalli V, Chauhan V, Bahrudeen MNM, Almeida BLB, Palma CSD, Dash S, Ribeiro AS. Sequence-dependent model of genes with dual σ factor preference. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194812. [PMID: 35338024 DOI: 10.1016/j.bbagrm.2022.194812] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/08/2022] [Accepted: 03/16/2022] [Indexed: 10/18/2022]
Abstract
Escherichia coli uses σ factors to quickly control large gene cohorts during stress conditions. While most of its genes respond to a single σ factor, approximately 5% of them have dual σ factor preference. The most common are those responsive to both σ70, which controls housekeeping genes, and σ38, which activates genes during stationary growth and stresses. Using RNA-seq and flow-cytometry measurements, we show that 'σ70+38 genes' are nearly as upregulated in stationary growth as 'σ38 genes'. Moreover, we find a clear quantitative relationship between their promoter sequence and their response strength to changes in σ38 levels. We then propose and validate a sequence dependent model of σ70+38 genes, with dual sensitivity to σ38 and σ70, that is applicable in the exponential and stationary growth phases, as well in the transient period in between. We further propose a general model, applicable to other stresses and σ factor combinations. Given this, promoters controlling σ70+38 genes (and variants) could become important building blocks of synthetic circuits with predictable, sequence-dependent sensitivity to transitions between the exponential and stationary growth phases.
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Affiliation(s)
- Ines S C Baptista
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Vinodh Kandavalli
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland; Department of Cell and Molecular Biology, Uppsala University, Uppsala 752 37, Sweden
| | - Vatsala Chauhan
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Mohamed N M Bahrudeen
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Bilena L B Almeida
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Cristina S D Palma
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Suchintak Dash
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Andre S Ribeiro
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland; Center of Technology and Systems (CTS-Uninova), NOVA University of Lisbon, 2829-516 Monte de Caparica, Portugal.
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11
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Sharma VK, Akavaram S, Bayles DO. Genomewide transcriptional response of Escherichia coli O157:H7 to norepinephrine. BMC Genomics 2022; 23:107. [PMID: 35135480 PMCID: PMC8822769 DOI: 10.1186/s12864-021-08167-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/10/2021] [Indexed: 01/18/2023] Open
Abstract
Background Chemical signaling between a mammalian host and intestinal microbes is health and maintenance of ‘healthy’ intestinal microbiota. Escherichia coli O157:H7 can hijack host- and microbiota-produced chemical signals for survival in a harsh and nutritionally competitive gastrointestinal environment and for intestinal colonization. Norepinephrine (NE) produced by sympathetic neurons of the enteric nervous system has been shown in vitro to induce expression of genes controlling E. coli O157:H7 swimming motility, acid resistance, and adherence to epithelial cells. A previous study used a microarray approach to identify differentially expressed genes in E. coli O157:H7 strain EDL933 in response to NE. To elucidate a comprehensive transcriptional response to NE, we performed RNA-Seq on rRNA-depleted RNA of E. coli O157:H7 strain NADC 6564, an isolate of a foodborne E. coli O157:H7 strain 86–24. The reads generated by RNA-Seq were mapped to NADC 6564 genome using HiSat2. The mapped reads were quantified by htseq-count against the genome of strain NADC 6564. The differentially expressed genes were identified by analyzing quantified reads by DESeq2. Results Of the 585 differentially expressed genes (≥ 2.0-fold; p < 0.05), many encoded pathways promoting ability of E. coli O157:H7 strain NADC 6564 to colonize intestines of carrier animals and to produce disease in an incidental human host through increased adherence to epithelial cells and production of Shiga toxins. In addition, NE exposure also induced the expression of genes encoding pathways conferring prolonged survival at extreme acidity, controlling influx/efflux of specific nutrients/metabolites, and modulating tolerance to various stressors. A correlation was also observed between the EvgS/EvgA signal transduction system and the ability of bacterial cells to survive exposure to high acidity for several hours. Many genes involved in nitrogen, sulfur, and amino acid uptake were upregulated while genes linked to iron (Fe3+) acquisition and transport were downregulated. Conclusion The availability of physiological levels of NE in gastrointestinal tract could serve as an important cue for E. coli O157:H7 to engineer its virulence, stress, and metabolic pathways for colonization in reservoir animals, such as cattle, causing illness in humans, and surviving outside of a host. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08167-z.
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Affiliation(s)
- Vijay K Sharma
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, ARS-USDA, Ames, IA, 50010, USA.
| | - Suryatej Akavaram
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, ARS-USDA, Ames, IA, 50010, USA.,Current address: 4302 TX-332, Freeport, TX, 77541, USA
| | - Darrell O Bayles
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, ARS-USDA, Ames, IA, 50010, USA
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12
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Valencia EY, Barros JP, Ferenci T, Spira B. A Broad Continuum of E. coli Traits in Nature Associated with the Trade-off Between Self-preservation and Nutritional Competence. MICROBIAL ECOLOGY 2022; 83:68-82. [PMID: 33846820 DOI: 10.1007/s00248-021-01751-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/05/2021] [Indexed: 06/12/2023]
Abstract
A trade-off between reproduction and survival is a characteristic of many organisms. In bacteria, growth is constrained when cellular resources are channelled towards environmental stress protection. At the core of this trade-off in Escherichia coli is RpoS, a sigma factor that diverts transcriptional resources towards general stress resistance. The constancy of RpoS levels in natural isolates is unknown. A uniform RpoS content in E. coli would impart a narrow range of resistance properties to the species, whereas a diverse set of RpoS levels in nature should result in a diverse range of stress susceptibilities. We explore the diversity of trade-off settings and phenotypes by measuring the level of RpoS protein in strains of E. coli cohabiting in a natural environment. Strains from a stream polluted with domestic waste were investigated in monthly samples. Analyses included E. coli phylogroup classification, RpoS protein level, RpoS-dependent stress phenotypes and the sequencing of rpoS mutations. The most striking finding was the continuum of RpoS levels, with a 100-fold range of RpoS amounts consistently found in individuals in the stream. Approximately 1.8% of the sampled strains carried null or non-synonymous mutations in rpoS. The natural isolates also exhibited a broad (>100-fold) range of stress resistance responses. Our results are consistent with the view that a multiplicity of survival-multiplication trade-off settings is a feature of the species E. coli. The phenotypic diversity resulting from the trade-off permits bet-hedging and the adaptation of E. coli strains to a very broad range of environments.
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Affiliation(s)
- Estela Ynes Valencia
- Departamento de Microbiologia, Instituto de Ciências Biomédicas Universidade de São Paulo, São Paulo, SP, Brazil
| | - Jackeline Pinheiro Barros
- Departamento de Microbiologia, Instituto de Ciências Biomédicas Universidade de São Paulo, São Paulo, SP, Brazil
| | - Thomas Ferenci
- School of Life and Environmental Sciences, University of Sydney, 6/403 Pacific Highway, Sydney, New South Wales, 2070, Australia
| | - Beny Spira
- Departamento de Microbiologia, Instituto de Ciências Biomédicas Universidade de São Paulo, São Paulo, SP, Brazil.
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13
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Du Y, Wang X, Han Z, Hua Y, Yan K, Zhang B, Zhao W, Wan C. Polyphosphate Kinase 1 Is a Pathogenesis Determinant in Enterohemorrhagic Escherichia coli O157:H7. Front Microbiol 2021; 12:762171. [PMID: 34777317 PMCID: PMC8578739 DOI: 10.3389/fmicb.2021.762171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 10/08/2021] [Indexed: 11/16/2022] Open
Abstract
The ppk1 gene encodes polyphosphate kinase (PPK1), which is the major catalytic enzyme that Escherichia coli utilizes to synthesize inorganic polyphosphate (polyP). The aim of this study was to explore the role of PPK1 in the pathogenesis of Enterohemorrhagic E. coli O157:H7 (EHEC O157:H7). An isogenic in-frame ppk1 deletion mutant (Δppk1) and ppk1 complemented mutant (Cppk1) were constructed and characterized in comparison to wild-type (WT) EHEC O157:H7 strain EDL933w by microscope observation and growth curve analysis. Survival rates under heat stress and acid tolerance, both of which the bacteria would face during pathogenesis, were compared among the three strains. LoVo cells and a murine model of intestinal colitis were used as the in vitro and in vivo models, respectively, to evaluate the effect of PPK1 on adhesion and invasion during the process of pathogenesis. Real-time reverse-transcription PCR of regulatory gene rpoS, adhesion gene eae, and toxin genes stx1 and stx2 was carried out to corroborate the results from the in vitro and in vivo models. The ppk1 deletion mutant exhibited disrupted polyP levels, but not morphology and growth characteristics. The survival rate of the Δppk1 strain under stringent environmental conditions was lower as compared with WT and Cppk1. The in vitro assays showed that deletion of the ppk1 gene reduced the adhesion, formation of attaching and effacing (A/E) lesions, and invasive ability of EHEC O157:H7. Moreover, the virulence of the Δppk1 in BALB/c mice was weaker as compared with the other two strains. Additionally, mRNA expression of rpoS, eae, stx1 and stx2 were consistent with the in vitro and in vivo results. In conclusion: EHEC O157:H7 requires PPK1 for both survival under harsh environmental conditions and virulence in vivo.
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Affiliation(s)
- Yanli Du
- School of Medical Technology and Nursing, Shenzhen Polytechnic, Shenzhen, China
| | - Xiangyu Wang
- Department of Gastroenterology, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, China.,Department of Microbiology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Zongli Han
- Department of Neurosurgery, Peking University Shenzhen Hospital, Shenzhen, China
| | - Ying Hua
- Department of Microbiology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Kaina Yan
- Department of Microbiology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Bao Zhang
- Department of Microbiology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Wei Zhao
- Department of Microbiology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Chengsong Wan
- Department of Microbiology, School of Public Health, Southern Medical University, Guangzhou, China.,Key Laboratory of Tropical Disease Research of Guangdong Province, Guangzhou, China
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14
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Mohiuddin SG, Ghosh S, Ngo HG, Sensenbach S, Karki P, Dewangan NK, Angardi V, Orman MA. Cellular Self-Digestion and Persistence in Bacteria. Microorganisms 2021; 9:2269. [PMID: 34835393 PMCID: PMC8626048 DOI: 10.3390/microorganisms9112269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 11/30/2022] Open
Abstract
Cellular self-digestion is an evolutionarily conserved process occurring in prokaryotic cells that enables survival under stressful conditions by recycling essential energy molecules. Self-digestion, which is triggered by extracellular stress conditions, such as nutrient depletion and overpopulation, induces degradation of intracellular components. This self-inflicted damage renders the bacterium less fit to produce building blocks and resume growth upon exposure to fresh nutrients. However, self-digestion may also provide temporary protection from antibiotics until the self-digestion-mediated damage is repaired. In fact, many persistence mechanisms identified to date may be directly or indirectly related to self-digestion, as these processes are also mediated by many degradative enzymes, including proteases and ribonucleases (RNases). In this review article, we will discuss the potential roles of self-digestion in bacterial persistence.
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Affiliation(s)
| | | | | | | | | | | | | | - Mehmet A. Orman
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77004, USA; (S.G.M.); (S.G.); (H.G.N.); (S.S.); (P.K.); (N.K.D.); (V.A.)
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15
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Nahar S, Jeong HL, Kim Y, Ha AJW, Roy PK, Park SH, Ashrafudoulla M, Mizan MFR, Ha SD. Inhibitory effects of Flavourzyme on biofilm formation, quorum sensing, and virulence genes of foodborne pathogens Salmonella Typhimurium and Escherichia coli. Food Res Int 2021; 147:110461. [PMID: 34399461 DOI: 10.1016/j.foodres.2021.110461] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/23/2021] [Accepted: 05/23/2021] [Indexed: 12/23/2022]
Abstract
Salmonella enterica and Shiga toxin-producing (or verotoxin-producing) Escherichia coli are major foodborne pathogens, posing substantial food safety risks. Due to the negative effects of chemical treatment against foodborne pathogens, the application of enzyme-based techniques is currently receiving great attention. Here, we evaluated the inhibitory properties of Flavourzyme, a commercial peptidase, against these two foodborne pathogens. We noticed 4.0 and 5.5 log inhibition of biofilm formation by S. Typhimurium and E. coli, respectively, while treated with sub-minimum inhibitory concentrations of Flavourzyme for 24 h. For both bacteria, the enzyme exhibited quorum-quenching activity, preventing autoinducer-2 production completely by E. coli. In addition, Flavourzyme significantly suppressed the relative expression levels of biofilm-forming, quorum sensing, and virulence regulatory genes as measured by qRT-PCR. Based on our results, we suggest the use of Flavourzyme as a preventive agent against foodborne pathogens that possibly acts by inhibiting bacterial self-defense mechanisms following disruption of cellular proteins. This finding may shed light on how enzymes can be applied as a novel weapon to control foodborne illnesses to ensure food safety and public health.
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Affiliation(s)
- Shamsun Nahar
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 17546, Republic of Korea
| | - Ha Lim Jeong
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 17546, Republic of Korea
| | - Younsoo Kim
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 17546, Republic of Korea
| | - Angela Jie-Won Ha
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 17546, Republic of Korea
| | - Pantu Kumar Roy
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 17546, Republic of Korea
| | - Si Hong Park
- Department of Food Science & Technology, Oregon State University, Corvallis, OR, USA
| | - Md Ashrafudoulla
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 17546, Republic of Korea
| | - Md Furkanur Rahaman Mizan
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 17546, Republic of Korea
| | - Sang-Do Ha
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 17546, Republic of Korea.
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16
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Byrd BA, Zenick B, Rocha-Granados MC, Englander HE, Hare PJ, LaGree TJ, DeMarco AM, Mok WWK. The AcrAB-TolC Efflux Pump Impacts Persistence and Resistance Development in Stationary-Phase Escherichia coli following Delafloxacin Treatment. Antimicrob Agents Chemother 2021; 65:e0028121. [PMID: 34097492 PMCID: PMC8284433 DOI: 10.1128/aac.00281-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 06/01/2021] [Indexed: 11/20/2022] Open
Abstract
Bacteria have a repertoire of strategies to overcome antibiotics in clinical use, complicating our ability to treat and cure infectious diseases. In addition to evolving resistance, bacteria within genetically clonal cultures can undergo transient phenotypic changes and tolerate high doses of antibiotics. These cells, termed persisters, exhibit heterogeneous phenotypes; the strategies that a bacterial population deploys to overcome one class of antibiotics can be distinct from those needed to survive treatment with drugs with another mode of action. It was previously reported that fluoroquinolones, which target DNA topoisomerases, retain the capacity to kill nongrowing bacteria that tolerate other classes of antibiotics. Here, we show that in Escherichia coli stationary-phase cultures and colony biofilms, persisters that survive treatment with the anionic fluoroquinolone delafloxacin depend on the AcrAB-TolC efflux pump. In contrast, we did not detect this dependence on AcrAB-TolC in E. coli persisters that survive treatment with three other fluoroquinolone compounds. We found that the loss of AcrAB-TolC activity via genetic mutations or chemical inhibition not only reduces delafloxacin persistence in nongrowing E. coli MG1655 or EDL933 (an E. coli O157:H7 strain), but it limits resistance development in progenies derived from delafloxacin persisters that were given the opportunity to recover in nutritive medium following antibiotic treatment. Our findings highlight the heterogeneity in defense mechanisms that persisters use to overcome different compounds within the same class of antibiotics. They further indicate that efflux pump inhibitors can potentiate the activity of delafloxacin against stationary-phase E. coli and block resistance development in delafloxacin persister progenies.
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Affiliation(s)
- Brandon A. Byrd
- Department of Molecular Biology & Biophysics, UCONN Health, Farmington, Connecticut, USA
- School of Medicine, University of Connecticut, Farmington, Connecticut, USA
| | - Blesing Zenick
- Department of Molecular Biology & Biophysics, UCONN Health, Farmington, Connecticut, USA
| | | | - Hanna E. Englander
- Department of Physiology & Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Patricia J. Hare
- Department of Molecular Biology & Biophysics, UCONN Health, Farmington, Connecticut, USA
- School of Dental Medicine, University of Connecticut, Farmington, Connecticut, USA
| | - Travis J. LaGree
- Department of Molecular Biology & Biophysics, UCONN Health, Farmington, Connecticut, USA
| | - Angela M. DeMarco
- Department of Molecular Biology & Biophysics, UCONN Health, Farmington, Connecticut, USA
| | - Wendy W. K. Mok
- Department of Molecular Biology & Biophysics, UCONN Health, Farmington, Connecticut, USA
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17
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Roy PK, Ha AJW, Mizan MFR, Hossain MI, Ashrafudoulla M, Toushik SH, Nahar S, Kim YK, Ha SD. Effects of environmental conditions (temperature, pH, and glucose) on biofilm formation of Salmonella enterica serotype Kentucky and virulence gene expression. Poult Sci 2021; 100:101209. [PMID: 34089933 PMCID: PMC8182266 DOI: 10.1016/j.psj.2021.101209] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/01/2021] [Accepted: 04/11/2021] [Indexed: 12/20/2022] Open
Abstract
Salmonella is a foodborne pathogen and an emerging zoonotic bacterial threat in the food industry. The aim of this study was to evaluate the biofilm formation by a cocktail culture of 3 wild isolates of Salmonella enterica serotype Kentucky on plastic (PLA), silicon rubber (SR), and chicken skin surfaces under various temperatures (4, 10, 25, 37, and 42°C) and pH values (4.0, 5.0, 6.0, 7.0, and 8.0). Then, at the optimum temperature and pH, the effects of supplementation with glucose (0, 0.025, 0.05, and 0.4% w/v) on biofilm formation were assessed on each of the surfaces. The results indicated that higher temperatures (25 to 42°C) and pH values (7.0 and 8.0) led to more robust biofilm formation than lower temperatures (4 and 10°C) and lower pH levels (4.0 to 6.0). Moreover, biofilm formation was induced by 0.025% glucose during incubation at the optimum temperature (37°C) and pH (7.0) but inhibited by 0.4% glucose. Consistent with this finding, virulence related gene (rpoS, rpoH, hilA, and avrA) expression was increased at 0.025% glucose and significantly reduced at 0.4% glucose. This results also confirmed by field emission scanning electron microscope, confocal laser scanning microscopy, and autoinducer-2 determination. This study concluded that optimum environmental conditions (temperature 37°C, pH 7.0, and 0.25% glucose) exhibited strong biofilm formation on food and food contract surfaces as well as increased the virulence gene expression levels, indicating that these environmental conditions might be threating conditions for food safety.
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Affiliation(s)
- Pantu Kumar Roy
- Advanced Food Safety Research Group, Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 456-756, Republic of Korea
| | - Angela Ji-Won Ha
- Advanced Food Safety Research Group, Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 456-756, Republic of Korea
| | - Md Furkanur Rahaman Mizan
- Advanced Food Safety Research Group, Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 456-756, Republic of Korea
| | - Md Iqbal Hossain
- Advanced Food Safety Research Group, Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 456-756, Republic of Korea
| | - Md Ashrafudoulla
- Advanced Food Safety Research Group, Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 456-756, Republic of Korea
| | - Sazzad Hossen Toushik
- Advanced Food Safety Research Group, Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 456-756, Republic of Korea
| | - Shamsun Nahar
- Advanced Food Safety Research Group, Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 456-756, Republic of Korea
| | - Yu Kyung Kim
- Advanced Food Safety Research Group, Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 456-756, Republic of Korea
| | - Sang-Do Ha
- Advanced Food Safety Research Group, Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 456-756, Republic of Korea.
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18
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Sheikh SW, Ali A, Ahsan A, Shakoor S, Shang F, Xue T. Insights into Emergence of Antibiotic Resistance in Acid-Adapted Enterohaemorrhagic Escherichia coli. Antibiotics (Basel) 2021; 10:antibiotics10050522. [PMID: 34063307 PMCID: PMC8147483 DOI: 10.3390/antibiotics10050522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/15/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
The emergence of multidrug-resistant pathogens presents a global challenge for treating and preventing disease spread through zoonotic transmission. The water and foodborne Enterohaemorrhagic Escherichia coli (EHEC) are capable of causing intestinal and systemic diseases. The root cause of the emergence of these strains is their metabolic adaptation to environmental stressors, especially acidic pH. Acid treatment is desired to kill pathogens, but the protective mechanisms employed by EHECs cross-protect against antimicrobial peptides and thus facilitate opportunities for survival and pathogenesis. In this review, we have discussed the correlation between acid tolerance and antibiotic resistance, highlighting the identification of novel targets for potential production of antimicrobial therapeutics. We have also summarized the molecular mechanisms used by acid-adapted EHECs, such as the two-component response systems mediating structural modifications, competitive inhibition, and efflux activation that facilitate cross-protection against antimicrobial compounds. Moving beyond the descriptive studies, this review highlights low pH stress as an emerging player in the development of cross-protection against antimicrobial agents. We have also described potential gene targets for innovative therapeutic approaches to overcome the risk of multidrug-resistant diseases in healthcare and industry.
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Affiliation(s)
- Salma Waheed Sheikh
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
| | - Ahmad Ali
- School of Agronomy, Anhui Agricultural University, Hefei 230036, China;
| | - Asma Ahsan
- Faculty of Life Sciences, University of Central Punjab, Lahore 54000, Punjab, Pakistan;
| | - Sidra Shakoor
- Station de Neucfchateau, CIRAD, 97130 Sainte-Marie, Capesterre Belle Eau, Guadeloupe, France;
| | - Fei Shang
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
- Correspondence: (F.S.); (T.X.); Tel.: +86-551-657-87380 (F.S.); +86-551-657-80690 (T.X.)
| | - Ting Xue
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
- Correspondence: (F.S.); (T.X.); Tel.: +86-551-657-87380 (F.S.); +86-551-657-80690 (T.X.)
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19
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Yu L, Zhang S, Xu Y, Mi X, Xing T, Li J, Zhang L, Gao F, Jiang Y. Acid resistance of E. coli O157:H7 and O26:H11 exposure to lactic acid revealed by transcriptomic analysis. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2020.110352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Carter MQ, Pham A, Huynh S, Parker CT, Miller A, He X, Hu B, Chain PSG. DNA adenine methylase, not the PstI restriction-modification system, regulates virulence gene expression in Shiga toxin-producing Escherichia coli. Food Microbiol 2020; 96:103722. [PMID: 33494894 DOI: 10.1016/j.fm.2020.103722] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/15/2020] [Accepted: 12/22/2020] [Indexed: 01/20/2023]
Abstract
We previously reported a distinct methylome between the two Shiga toxin-producing Escherichia coli (STEC) O145:H28 strains linked to the 2010 U.S. lettuce-associated outbreak (RM13514) and the 2007 Belgium ice cream-associated outbreak (RM13516), respectively. This difference was thought to be attributed to a prophage encoded type II restriction-modification system (PstI R-M) in RM13514. Here, we characterized this PstI R-M system in comparison to DNA adenine methylase (Dam), a highly conserved enzyme in γ proteobacteria, by functional genomics. Deficiency in Dam led to a differential expression of over 1000 genes in RM13514, whereas deficiency in PstI R-M only impacted a few genes transcriptionally. Dam regulated genes involved in diverse functions, whereas PstI R-M regulated genes mostly encoding transporters and adhesins. Dam regulated a large number of genes located on prophages, pathogenicity islands, and plasmids, including Shiga toxin genes, type III secretion system (TTSS) genes, and enterohemolysin genes. Production of Stx2 in dam mutant was significantly higher than in RM13514, supporting a role of Dam in maintaining lysogeny of Stx2-prophage. However, following mitomycin C treatment, Stx2 in RM13514 was significantly higher than that of dam or PstI R-M deletion mutant, implying that both Dam and PstI R-M contributed to maximum Stx2 production.
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Affiliation(s)
- Michelle Qiu Carter
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Produce Safety and Microbiology Research Unit, Albany, CA, USA.
| | - Antares Pham
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Produce Safety and Microbiology Research Unit, Albany, CA, USA
| | - Steven Huynh
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Produce Safety and Microbiology Research Unit, Albany, CA, USA
| | - Craig T Parker
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Produce Safety and Microbiology Research Unit, Albany, CA, USA
| | - Avalon Miller
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Produce Safety and Microbiology Research Unit, Albany, CA, USA
| | - Xiaohua He
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Foodborne Toxin and Detection Research Unit, Albany, CA, USA
| | - Bin Hu
- Biosecurity and Public Health Group, Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Patrick S G Chain
- Biosecurity and Public Health Group, Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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21
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Barron MR, Cieza RJ, Hill DR, Huang S, Yadagiri VK, Spence JR, Young VB. The Lumen of Human Intestinal Organoids Poses Greater Stress to Bacteria Compared to the Germ-Free Mouse Intestine: Escherichia coli Deficient in RpoS as a Colonization Probe. mSphere 2020; 5:e00777-20. [PMID: 33177212 PMCID: PMC7657587 DOI: 10.1128/msphere.00777-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/23/2020] [Indexed: 02/07/2023] Open
Abstract
Pluripotent stem-cell-derived human intestinal organoids (HIOs) are three-dimensional, multicellular structures that model a naive intestinal epithelium in an in vitro system. Several published reports have investigated the use of HIOs to study host-microbe interactions. We recently demonstrated that microinjection of the nonpathogenic Escherichia coli strain ECOR2 into HIOs induced morphological and functional maturation of the HIO epithelium, including increased secretion of mucins and cationic antimicrobial peptides. In the current work, we use ECOR2 as a biological probe to further characterize the environment present in the HIO lumen. We generated an isogenic mutant in the general stress response sigma factor RpoS and employed this mutant to compare challenges faced by a bacterium during colonization of the HIO lumen relative to the germ-free mouse intestine. We demonstrate that the loss of RpoS significantly decreases the ability of ECOR2 to colonize HIOs, although it does not prevent colonization of germ-free mice. These results indicate that the HIO lumen is a more restrictive environment to E. coli than the germ-free mouse intestine, thus increasing our understanding of the HIO model system as it pertains to studying the establishment of intestinal host-microbe symbioses.IMPORTANCE Technological advancements have driven and will continue to drive the adoption of organotypic systems for investigating host-microbe interactions within the human intestinal ecosystem. Using E. coli deficient in the RpoS-mediated general stress response, we demonstrate that the type or severity of microbial stressors within the HIO lumen is more restrictive than those of the in vivo environment of the germ-free mouse gut. This study provides important insight into the nature of the HIO microenvironment from a microbiological standpoint.
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Affiliation(s)
- Madeline R Barron
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Roberto J Cieza
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - David R Hill
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Sha Huang
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Veda K Yadagiri
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Jason R Spence
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Vincent B Young
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
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22
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Abstract
Enterohemorrhagic E. coli is a significant human pathogen that can cause severe disease due to the release of Shiga toxins. The toxins are encoded within lysogenic bacteriophage and controlled by antitermination of the phage late promoter, PR′. This promoter is always active, but terminated immediately downstream during lysogeny. A byproduct of antitermination regulation is transcription of a short RNA that is thought to be nonfunctional. Here we demonstrate that in Shiga toxin-encoding phages, this short RNA is a Hfq-binding regulatory small RNA. The small RNA represses toxin production threefold under lysogenic conditions and promotes high cell density growth. Lysogenic bacteriophages are highly abundant and our results suggest that antiterminated phage promoters may be a rich source of regulatory RNAs. Enterohemorrhagic Escherichia coli is a significant human pathogen that causes disease ranging from hemorrhagic colitis to hemolytic uremic syndrome. The latter can lead to potentially fatal renal failure and is caused by the release of Shiga toxins that are encoded within lambdoid bacteriophages. The toxins are encoded within the late transcript of the phage and are regulated by antitermination of the PR′ late promoter during lytic induction of the phage. During lysogeny, the late transcript is prematurely terminated at tR′ immediately downstream of PR′, generating a short RNA that is a byproduct of antitermination regulation. We demonstrate that this short transcript binds the small RNA chaperone Hfq, and is processed into a stable 74-nt regulatory small RNA that we have termed StxS. StxS represses expression of Shiga toxin 1 under lysogenic conditions through direct interactions with the stx1AB transcript. StxS acts in trans to activate expression of the general stress response sigma factor, RpoS, through direct interactions with an activating seed sequence within the 5′ UTR. Activation of RpoS promotes high cell density growth under nutrient-limiting conditions. Many phages utilize antitermination to regulate the lytic/lysogenic switch and our results demonstrate that short RNAs generated as a byproduct of this regulation can acquire regulatory small RNA functions that modulate host fitness.
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Schellhorn HE. Function, Evolution, and Composition of the RpoS Regulon in Escherichia coli. Front Microbiol 2020; 11:560099. [PMID: 33042067 PMCID: PMC7527412 DOI: 10.3389/fmicb.2020.560099] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 08/25/2020] [Indexed: 11/13/2022] Open
Abstract
For many bacteria, successful growth and survival depends on efficient adaptation to rapidly changing conditions. In Escherichia coli, the RpoS alternative sigma factor plays a central role in the adaptation to many suboptimal growth conditions by controlling the expression of many genes that protect the cell from stress and help the cell scavenge nutrients. Neither RpoS or the genes it controls are essential for growth and, as a result, the composition of the regulon and the nature of RpoS control in E. coli strains can be variable. RpoS controls many genetic systems, including those affecting pathogenesis, phenotypic traits including metabolic pathways and biofilm formation, and the expression of genes needed to survive nutrient deprivation. In this review, I review the origin of RpoS and assess recent transcriptomic and proteomic studies to identify features of the RpoS regulon in specific clades of E. coli to identify core functions of the regulon and to identify more specialized potential roles for the regulon in E. coli subgroups.
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Dissecting the in vivo dynamics of transcription locking due to positive supercoiling buildup. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194515. [PMID: 32113983 DOI: 10.1016/j.bbagrm.2020.194515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 02/07/2020] [Accepted: 02/20/2020] [Indexed: 01/04/2023]
Abstract
Positive supercoiling buildup (PSB) is a pervasive phenomenon in the transcriptional programs of Escherichia coli. After finding a range of Gyrase concentrations where the inverse of the transcription rate of a chromosome-integrated gene changes linearly with the inverse of Gyrase concentration, we apply a LineWeaver-Burk plot to dissect the expected in vivo transcription rate in absence of PSB. We validate the estimation by time-lapse microscopy of single-RNA production kinetics of the same gene when single-copy plasmid-borne, shown to be impervious to Gyrase inhibition. Next, we estimate the fraction of time in locked states and number of transcription events prior to locking, which we validate by measurements under Gyrase inhibition. Replacing the gene of interest by one with slower transcription rate decreases the fraction of time in locked states due to PSB. Finally, we combine data from both constructs to infer a range of possible transcription initiation locking kinetics in a chromosomal location, obtainable by tuning the transcription rate. We validate with measurements of transcription activity at different induction levels. This strategy for dissecting transcription initiation locking kinetics due to PSB can contribute to resolve the transcriptional programs of E. coli and in the engineering of synthetic genetic circuits.
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Prada-Prada S, Flórez-Castillo J, Farfán-García A, Guzmán F, Hernández-Peñaranda I. Antimicrobial activity of Ib-M peptides against Escherichia coli O157: H7. PLoS One 2020; 15:e0229019. [PMID: 32053687 PMCID: PMC7018034 DOI: 10.1371/journal.pone.0229019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/28/2020] [Indexed: 01/19/2023] Open
Abstract
The development of new antimicrobial peptides has become an attractive alternative to conventional antibiotics due to the increasing rates of microbial drug resistance. Ib-M corresponds to a family of cationic synthetic peptides, 20 amino acids in length, that have shown inhibitory effect against the non-pathogenic strain Escherichia coli K-12. This work evaluated the antimicrobial potential of Ib-M peptides against the pathogenic E. coli O157: H7 using a reference strain and a clinical isolate. The Ib-M peptides showed antibacterial activity against both strains of E. coli O157: H7; the minimum inhibitory concentration of Ib-M peptides ranged from 1.6 to 12.5 μM and the minimum bactericidal concentration ranged from 3.7 to 22.9 μM, being Ib-M1 and Ib-M2 the peptides that presented the highest inhibitory effect. Time-kill kinetics assay showed a reduction of the bacterial population by more than 95% after 4 hours of exposure to 1xMIC of Ib-M1. Low cytotoxicity was observed in VERO cells with 50% cytotoxic concentration in the range from 197.5 to more than 400 μM. All peptides showed a random structure in hydrophilic environments, except Ib-M1, and all of them transitioned to an α-helical structure when the hydrophobicity of the medium was increased. In conclusion, these findings support the in vitro antimicrobial effect of Ib-M peptides against the pathogenic bacteria E. coli O157: H7 and prove to be promising molecules for the development of new therapeutic alternatives.
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Affiliation(s)
- Sergio Prada-Prada
- Maestría en Investigación en Enfermedades Infecciosas, Facultad de Ciencias de la Salud, Grupo de Investigación en Ciencias Básicas y Aplicadas para la sostenibilidad – CIBAS, Universidad de Santander, Bucaramanga, Colombia
| | - Johanna Flórez-Castillo
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Naturales y Agropecuarias, Grupo de Investigación en Ciencias Básicas y Aplicadas para la sostenibilidad – CIBAS, Universidad de Santander, Bucaramanga, Colombia
| | - Ana Farfán-García
- Programa de Bacteriología y Laboratorio Clínico, Facultad de Ciencias de la Salud, Grupo de Investigación en Manejo Clínico – CLINIUDES, Universidad de Santander, Bucaramanga, Colombia
| | - Fanny Guzmán
- Laboratorio de Síntesis de Péptidos, Núcleo de Biotecnología Curauma (NBC), Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Indira Hernández-Peñaranda
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Naturales y Agropecuarias, Grupo de Investigación en Ciencias Básicas y Aplicadas para la sostenibilidad – CIBAS, Universidad de Santander, Bucaramanga, Colombia
- * E-mail:
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Tyagi D, Kraft AL, Levadney Smith S, Roof SE, Sherwood JS, Wiedmann M, Bergholz TM. Pre-Harvest Survival and Post-Harvest Chlorine Tolerance of Enterohemorrhagic Escherichia coli on Lettuce. Toxins (Basel) 2019; 11:E675. [PMID: 31752303 PMCID: PMC6891304 DOI: 10.3390/toxins11110675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/06/2019] [Accepted: 11/13/2019] [Indexed: 11/16/2022] Open
Abstract
In the field, foodborne pathogens such as enterohemorrhagic Escherichia coli (EHEC) are capable of surviving on produce over time, yet little is known about how these pathogens adapt to this environment. To assess the impact of pre-harvest environmental conditions on EHEC survival, we quantified survival on romaine lettuce under two relative humidity (75% and 45%) and seasonal conditions (March and June). Greenhouse-grown lettuce was spray-inoculated with EHEC and placed in a growth chamber, mimicking conditions typical for June and March in Salinas Valley, California. Bacteria were enumerated on days 0, 1, 3, and 5 post-inoculation. Overall, we found that the effect of relative humidity on EHEC survival depended on the seasonal conditions. Under June seasonal conditions, higher relative humidity led to lower survival, and lower relative humidity led to greater survival, five days post-inoculation. Under March seasonal conditions, the impact of relative humidity on EHEC survival was minimal over the five days. The bacteria were also tested for their ability to survive a chlorine decontamination wash. Inoculated lettuce was incubated under the June 75% relative humidity conditions and then washed with a 50 ppm sodium hypochlorite solution (40 ppm free chlorine). When incubated under June seasonal conditions for three to five days, EHEC strains showed increased tolerance to chlorine (adj. p < 0.05) compared to chlorine tolerance upon inoculation onto lettuce. This indicated that longer incubation on lettuce led to greater EHEC survival upon exposure to chlorine. Subsequent transcriptome analysis identified the upregulation of osmotic and oxidative stress response genes by EHEC after three and five days of incubation on pre-harvest lettuce. Assessing the physiological changes in EHEC that occur during association with pre-harvest lettuce is important for understanding how changing tolerance to post-harvest control measures may occur.
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Affiliation(s)
- Deepti Tyagi
- Department of Microbiological Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Autumn L Kraft
- Department of Microbiological Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Sara Levadney Smith
- Department of Microbiological Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Sherry E Roof
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Julie S Sherwood
- Department of Microbiological Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Teresa M Bergholz
- Department of Microbiological Sciences, North Dakota State University, Fargo, ND 58102, USA
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Bezanson G, Mader D, Fillmore S, Bach S, Delaquis P. Reaction of Surrogate Escherichia coli Serotype O157:H7 and Non-O157 Strains to Nutrient Starvation: Variation in Phenotype and Transcription of Stress Response Genes and Behavior on Lettuce Plants in the Field. J Food Prot 2019; 82:1988-2000. [PMID: 31644333 DOI: 10.4315/0362-028x.jfp-19-072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Preharvest contamination with bacteria borne by irrigation water may result in leafy vegetables serving as vehicles for transmission of Shiga toxin-producing Escherichia coli (STEC) to humans. The influence of starvation-associated stress on the behavior of non-toxin-producing strains of E. coli serotype O157:H7 and serotypes O26, O103, O111, and O145 was examined subsequent to their introduction to the phyllosphere of field-grown romaine lettuce as inocula simulating starved (96 h in sterile deionized water) and nutrient-depleted (24 h broth culture) cells. As with E. coli O157:H7, leaf populations of the non-O157 strains declined rapidly during the first 72 h postinoculation, displaying the biphasic decay curve typical of serotype O157:H7 isolates. Preinoculation treatment appeared not to influence decay rates greatly (P > 0.5), but strain-specific differences (persistence period and attachment proficiency) indicated that serotype O103:H2 strain PARC445 was a better survivor. Also assessed was the impact of preinoculation treatment on phenotypes key to leaf colonization and survival and the expression of starvation stress-associated genes. The 96-h starvation period enhanced biofilm formation in one strain but reduced motility and autoinducer 2 formation in all five study strains relative to those characteristics in stationary-phase cells. Transcription of rpoS, dps, uspA, and gapA was reduced significantly (P < 0.05) in starvation-stressed cells relative to that for exponential- and stationary-phase cultures. Strain-specific differences were observed; serotype O103:H2 PARC445 had greater downturns than did serotype O157:H7 and other non-O157 strains. Within this particular cohort, the behavior of the representative serotype O157:H7 strain, PARC443 (ATCC 700728), was not predictive of behavior of non-O157 members of this STEC group.
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Affiliation(s)
- Greg Bezanson
- Agriculture and Agri-Food Canada, Kentville Research and Development Centre, 32 Main Street, Kentville, Nova Scotia, Canada B4N 1J
| | - David Mader
- Agriculture and Agri-Food Canada, Kentville Research and Development Centre, 32 Main Street, Kentville, Nova Scotia, Canada B4N 1J
| | - Sherry Fillmore
- Agriculture and Agri-Food Canada, Kentville Research and Development Centre, 32 Main Street, Kentville, Nova Scotia, Canada B4N 1J
| | - Susan Bach
- Agriculture and Agri-Food Canada, Brandon Research and Development Centre, 2701 Grand Valley Road, Brandon, Manitoba, Canada R7A 5Y3
| | - Pascal Delaquis
- Agriculture and Agri-Food Canada, Summerland Research and Development Centre, 4200 Highway 97, Summerland, British Columbia, Canada V0H 1Z0
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Yan Z, Hussain S, Wang X, Bernstein HD, Bardwell JCA. Chaperone OsmY facilitates the biogenesis of a major family of autotransporters. Mol Microbiol 2019; 112:1373-1387. [PMID: 31369167 DOI: 10.1111/mmi.14358] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2019] [Indexed: 12/26/2022]
Abstract
OsmY is a widely conserved but poorly understood 20 kDa periplasmic protein. Using a folding biosensor, we previously obtained evidence that OsmY has molecular chaperone activity. To discover natural OsmY substrates, we screened for proteins that are destabilized and thus present at lower steady-state levels in an osmY-null strain. The abundance of an outer membrane protein called antigen 43 was substantially decreased and its β-barrel domain was undetectable in the outer membrane of an osmY-null strain. Antigen 43 is a member of the diffuse adherence family of autotransporters. Like strains that are defective in antigen 43 production, osmY-null mutants failed to undergo cellular autoaggregation. In vitro, OsmY assisted in the refolding of the antigen 43 β-barrel domain and protected it from added protease. Finally, an osmY-null strain that expressed two members of the diffuse adherence family of autotransporters that are distantly related to antigen 43, EhaA and TibA, contained reduced levels of the proteins and failed to undergo cellular autoaggregation. Taken together, our results indicate that OsmY is involved in the biogenesis of a major subset of autotransporters, a group of proteins that play key roles in bacterial pathogenesis.
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Affiliation(s)
- Zhen Yan
- Howard Hughes Medical Institute and Department of Molecular, Cellular & Development Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Sunyia Hussain
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Xu Wang
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Harris D Bernstein
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - James C A Bardwell
- Howard Hughes Medical Institute and Department of Molecular, Cellular & Development Biology, University of Michigan, Ann Arbor, MI, 48109, USA
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Antenucci F, Magnowska Z, Nimtz M, Roesch C, Jänsch L, Bojesen AM. Immunoproteomic characterization of outer membrane vesicles from hyper-vesiculating Actinobacillus pleuropneumoniae. Vet Microbiol 2019; 235:188-194. [PMID: 31383301 DOI: 10.1016/j.vetmic.2019.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/02/2019] [Accepted: 07/02/2019] [Indexed: 11/16/2022]
Abstract
Outer membrane vesicles (OMVs) are produced and secreted virtually by every known Gram-negative bacterium. Despite their non-live nature, they share antigenic characteristics with the bacteria they originate from. This, together with their relative ease of purification, casts the OMVs as a very promising and flexible tool in both human and veterinary vaccinology. The aim of the current work was to get an insight into the antigenic pattern of OMVs from the pig pathogen Actinobacillus pleuropneumoniae in the context of vaccine development. Accordingly, we designed a protocol combining 2D Western Blotting and mass spectrometric identification to robustly characterize the antigenic protein pattern of the vesicles. Our analysis revealed that A. pleuropneumoniae OMVs carry several immunoreactive virulence factors. Some of these proteins, LpoA, OsmY and MIDG2331_02184, have never previously been documented as antigenic in A. pleuropneumoniae or other pathogenic bacteria. Additionally, we showed that despite their relative abundance, proteins such as FrpB and DegQ do not contribute to the antigenic profile of A. pleuropneumoniae OMVs.
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Affiliation(s)
- Fabio Antenucci
- Department of Veterinary and Animal Sciences, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, University of Copenhagen, Copenhagen, Denmark.
| | - Zofia Magnowska
- Department of Veterinary and Animal Sciences, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, University of Copenhagen, Copenhagen, Denmark.
| | - Manfred Nimtz
- Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124, Braunschweig, Germany.
| | - Camille Roesch
- Izon Science Ltd, Batiment Laennec, 60 Avenue Rockefeller, 69008, Lyon, France.
| | - Lothar Jänsch
- Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124, Braunschweig, Germany.
| | - Anders Miki Bojesen
- Department of Veterinary and Animal Sciences, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, University of Copenhagen, Copenhagen, Denmark.
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Metabolomics-Driven Exploration of the Chemical Drug Space to Predict Combination Antimicrobial Therapies. Mol Cell 2019; 74:1291-1303.e6. [PMID: 31047795 PMCID: PMC6591011 DOI: 10.1016/j.molcel.2019.04.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 12/27/2018] [Accepted: 03/28/2019] [Indexed: 01/12/2023]
Abstract
Alternative to the conventional search for single-target, single-compound treatments, combination therapies can open entirely new opportunities to fight antibiotic resistance. However, combinatorial complexity prohibits experimental testing of drug combinations on a large scale, and methods to rationally design combination therapies are lagging behind. Here, we developed a combined experimental-computational approach to predict drug-drug interactions using high-throughput metabolomics. The approach was tested on 1,279 pharmacologically diverse drugs applied to the gram-negative bacterium Escherichia coli. Combining our metabolic profiling of drug response with previously generated metabolic and chemogenomic profiles of 3,807 single-gene deletion strains revealed an unexpectedly large space of inhibited gene functions and enabled rational design of drug combinations. This approach is applicable to other therapeutic areas and can unveil unprecedented insights into drug tolerance, side effects, and repurposing. The compendium of drug-associated metabolome profiles is available at https://zampierigroup.shinyapps.io/EcoPrestMet, providing a valuable resource for the microbiological and pharmacological communities. Metabolic profiling of E. coli response to 1,279 chemically diverse drugs Large space of nonessential gene functions affected by human-targeted drugs Genome-scale inference of drug targets and indirect mediators of drug response Metabolome and chemogenomic profiling predict epistatic interactions between drugs
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31
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Hussein SH, Samir R, Aziz RK, Toama MA. Two putative MmpL homologs contribute to antimicrobial resistance and nephropathy of enterohemorrhagic E. coli O157:H7. Gut Pathog 2019; 11:15. [PMID: 31019555 PMCID: PMC6471949 DOI: 10.1186/s13099-019-0296-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/27/2019] [Indexed: 11/11/2022] Open
Abstract
Background The serious human pathogen, E. coli serotype O157:H7, continues to gain antibiotic resistance, posing a public health threat. While this serotype’s genome has been sequenced, the role of 25% of its genes remains unknown, including genes conferring additional resistance. A prominent bacterial resistance mechanism is acquiring genes encoding efflux pumps, among which are the mycobacterial membrane proteins (Mmp), which contribute to virulence and membrane transport in mycobacteria. Here, we identified two potential mmp homologs (z4861 and yegN) in E. coli O157:H7, and we aimed to investigate their distribution among E. coli strains and their potential functions. Methods and results By screening different E. coli strains in vitro and in silico, we observed that yegN is more conserved than z4861. Using knockout mutants lacking either or both genes, we found that the mutants were more susceptible to fluoroquinolones than the parent strain and their secretomes included fewer virulence-related proteins. Moreover, histopathological examination of the kidneys of CD-1 mice infected by the wild-type or knockout strains indicated a greater impact of z4861 on pathogenesis and kidney damage than yegN, since both mutants lacking z4861 caused less severe kidney damage. The growth pattern of the wild-type was similar to that of mutant strains under aerobic and anaerobic conditions; yet, the mutant strains grew less when treated with subinhibitory dose of ciprofloxacin. Conclusion The previously unannotated gene product, Z4861, and its more conserved homolog, YegN, contribute to the kidney damage and resistance of E. coli O157:H7. Electronic supplementary material The online version of this article (10.1186/s13099-019-0296-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Salma H Hussein
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562 Egypt
| | - Reham Samir
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562 Egypt
| | - Ramy K Aziz
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562 Egypt
| | - Mohamed A Toama
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562 Egypt
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Dorich V, Brugger C, Tripathi A, Hoskins JR, Tong S, Suhanovsky MM, Sastry A, Wickner S, Gottesman S, Deaconescu AM. Structural basis for inhibition of a response regulator of σ S stability by a ClpXP antiadaptor. Genes Dev 2019; 33:718-732. [PMID: 30975721 PMCID: PMC6546054 DOI: 10.1101/gad.320168.118] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 03/19/2019] [Indexed: 11/25/2022]
Abstract
Dorich et al. present the first crystal structure of RssB bound to an antiadaptor, the DNA damage-inducible IraD. The structural data, together with mechanistic studies, suggest that RssB plasticity is critical for regulation of σS degradation. The stationary phase promoter specificity subunit σS (RpoS) is delivered to the ClpXP machinery for degradation dependent on the adaptor RssB. This adaptor-specific degradation of σS provides a major point for regulation and transcriptional reprogramming during the general stress response. RssB is an atypical response regulator and the only known ClpXP adaptor that is inhibited by multiple but dissimilar antiadaptors (IraD, IraP, and IraM). These are induced by distinct stress signals and bind to RssB in poorly understood manners to achieve stress-specific inhibition of σS turnover. Here we present the first crystal structure of RssB bound to an antiadaptor, the DNA damage-inducible IraD. The structure reveals that RssB adopts a compact closed architecture with extensive interactions between its N-terminal and C-terminal domains. The structural data, together with mechanistic studies, suggest that RssB plasticity, conferred by an interdomain glutamate-rich flexible linker, is critical for regulation of σS degradation. Structural modulation of interdomain linkers may thus constitute a general strategy for tuning response regulators.
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Affiliation(s)
- Victoria Dorich
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, USA
| | - Christiane Brugger
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, USA
| | - Arti Tripathi
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Joel R Hoskins
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Song Tong
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Margaret M Suhanovsky
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, USA
| | - Amita Sastry
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, USA
| | - Sue Wickner
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Susan Gottesman
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Alexandra M Deaconescu
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, USA
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Oliveira SMD, Goncalves NSM, Kandavalli VK, Martins L, Neeli-Venkata R, Reyelt J, Fonseca JM, Lloyd-Price J, Kranz H, Ribeiro AS. Chromosome and plasmid-borne P LacO3O1 promoters differ in sensitivity to critically low temperatures. Sci Rep 2019; 9:4486. [PMID: 30872616 PMCID: PMC6418193 DOI: 10.1038/s41598-019-39618-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 01/28/2019] [Indexed: 12/31/2022] Open
Abstract
Temperature shifts trigger genome-wide changes in Escherichia coli's gene expression. We studied if chromosome integration impacts on a gene's sensitivity to these shifts, by comparing the single-RNA production kinetics of a PLacO3O1 promoter, when chromosomally-integrated and when single-copy plasmid-borne. At suboptimal temperatures their induction range, fold change, and response to decreasing temperatures are similar. At critically low temperatures, the chromosome-integrated promoter becomes weaker and noisier. Dissection of its initiation kinetics reveals longer lasting states preceding open complex formation, suggesting enhanced supercoiling buildup. Measurements with Gyrase and Topoisomerase I inhibitors suggest hindrance to escape supercoiling buildup at low temperatures. Consistently, similar phenomena occur in energy-depleted cells by DNP at 30 °C. Transient, critically-low temperatures have no long-term consequences, as raising temperature quickly restores transcription rates. We conclude that the chromosomally-integrated PLacO3O1 has higher sensitivity to low temperatures, due to longer-lasting super-coiled states. A lesser active, chromosome-integrated native lac is shown to be insensitive to Gyrase overexpression, even at critically low temperatures, indicating that the rate of escaping positive supercoiling buildup is temperature and transcription rate dependent. A genome-wide analysis supports this, since cold-shock genes exhibit atypical supercoiling-sensitivities. This phenomenon might partially explain the temperature-sensitivity of some transcriptional programs of E. coli.
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Affiliation(s)
- Samuel M D Oliveira
- Laboratory of Biosystem Dynamics and Multi-Scaled Biodata Analysis and Modelling Research Community, Faculty of Medicine and Health Technology, Tampere University, Korkeakoulunkatu 7, 33720, Tampere, Finland
| | - Nadia S M Goncalves
- Laboratory of Biosystem Dynamics and Multi-Scaled Biodata Analysis and Modelling Research Community, Faculty of Medicine and Health Technology, Tampere University, Korkeakoulunkatu 7, 33720, Tampere, Finland
| | - Vinodh K Kandavalli
- Laboratory of Biosystem Dynamics and Multi-Scaled Biodata Analysis and Modelling Research Community, Faculty of Medicine and Health Technology, Tampere University, Korkeakoulunkatu 7, 33720, Tampere, Finland
| | - Leonardo Martins
- Laboratory of Biosystem Dynamics and Multi-Scaled Biodata Analysis and Modelling Research Community, Faculty of Medicine and Health Technology, Tampere University, Korkeakoulunkatu 7, 33720, Tampere, Finland
- CA3 CTS/UNINOVA. Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516, Caparica, Portugal
| | - Ramakanth Neeli-Venkata
- Laboratory of Biosystem Dynamics and Multi-Scaled Biodata Analysis and Modelling Research Community, Faculty of Medicine and Health Technology, Tampere University, Korkeakoulunkatu 7, 33720, Tampere, Finland
| | - Jan Reyelt
- Gene Bridges, Im Neuenheimer Feld 584, 69120, Heidelberg, Germany
| | - Jose M Fonseca
- CA3 CTS/UNINOVA. Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516, Caparica, Portugal
| | - Jason Lloyd-Price
- Biostatistics Department, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA, 02142, USA
| | - Harald Kranz
- Gene Bridges, Im Neuenheimer Feld 584, 69120, Heidelberg, Germany
| | - Andre S Ribeiro
- Laboratory of Biosystem Dynamics and Multi-Scaled Biodata Analysis and Modelling Research Community, Faculty of Medicine and Health Technology, Tampere University, Korkeakoulunkatu 7, 33720, Tampere, Finland.
- CA3 CTS/UNINOVA. Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516, Caparica, Portugal.
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Liu X, Xu J, Zhu J, Du P, Sun A. Combined Transcriptome and Proteome Analysis of RpoS Regulon Reveals Its Role in Spoilage Potential of Pseudomonas fluorescens. Front Microbiol 2019; 10:94. [PMID: 30787912 PMCID: PMC6372562 DOI: 10.3389/fmicb.2019.00094] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 01/16/2019] [Indexed: 12/23/2022] Open
Abstract
Microbial contamination is considered the main cause of food spoilage. Pseudomonas fluorescens is a typical spoilage bacterium contributing to a large extent to the spoilage process of proteinaceous foods. RpoS is known as an alternative sigma factor controlling stress resistance and virulence in many pathogens. Our previous work revealed that RpoS contributes to the spoilage activities of P. fluorescens by regulating resistance to different stress conditions, extracellular acylated homoserine lactone (AHL) levels, extracellular protease and total volatile basic nitrogen (TVB-N) production. However, RpoS-dependent genes in P. fluorescens remained undefined. RNA-seq transcriptomics analysis combined with quantitative proteomics analysis based on multiplexed isobaric tandem mass tag (TMT) labeling was performed in the P. fluorescens wild-type strain UK4 and its derivative carrying an rpoS mutation. A total of 375 differentially expressed coding sequences (DECs) and 212 differentially expressed proteins (DEPs) were identified. The DECs were further verified by qRT-PCR. The combined transcriptome and proteome analyses revealed the involvement of this regulator in several cellular processes, mainly including polysaccharide metabolism, intracellular secretion, extracellular structures, cell wall biogenesis, stress responses, and amino acid and biogenic amine metabolism, which may contribute to the biofilm formation, stress resistance, and spoilage activities of P. fluorescens. Moreover, we indeed observed that RpoS contributed to the production of the macrocolony biofilm's matrix. Our results provide insights into the regulatory network of RpoS and expand the knowledge about the role of RpoS in the functioning of P. fluorescens in food spoilage.
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Affiliation(s)
- Xiaoxiang Liu
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Jun Xu
- Hangzhou Lin'an District People's Hospital, Hangzhou, China
| | - Junli Zhu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, China
| | - Peng Du
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
| | - Aihua Sun
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
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Giannakopoulou N, Mendis N, Zhu L, Gruenheid S, Faucher SP, Le Moual H. The Virulence Effect of CpxRA in Citrobacter rodentium Is Independent of the Auxiliary Proteins NlpE and CpxP. Front Cell Infect Microbiol 2018; 8:320. [PMID: 30280092 PMCID: PMC6153362 DOI: 10.3389/fcimb.2018.00320] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/22/2018] [Indexed: 02/06/2023] Open
Abstract
Citrobacter rodentium is a murine pathogen used to model the intestinal infection caused by Enteropathogenic and Enterohemorrhagic Escherichia coli (EPEC and EHEC), two diarrheal pathogens responsible for morbidity and mortality in developing and developed countries, respectively. During infection, these bacteria must sense and adapt to the gut environment of the host. In order to adapt to changing environmental cues and modulate expression of specific genes, bacteria can use two-component signal transduction systems (TCS). We have shown that the deletion of the Cpx TCS in C. rodentium leads to a marked attenuation in virulence in C3H/HeJ mice. In E. coli, the Cpx TCS is reportedly activated in response to signals from the outer-membrane lipoprotein NlpE. We therefore investigated the role of NlpE in C. rodentium virulence. We also assessed the role of the reported negative regulator of CpxRA, CpxP. We found that as opposed to the ΔcpxRA strain, neither the ΔnlpE, ΔcpxP nor the ΔnlpEΔcpxP strains were significantly attenuated, and had similar in vivo localization to wild-type C. rodentium. The in vitro adherence of the Cpx auxiliary protein mutants, ΔnlpE, ΔcpxP, ΔnlpEΔcpxP, was comparable to wild-type C. rodentium, whereas the ΔcpxRA strain showed significantly decreased adherence. To further elucidate the mechanisms behind the contrasting virulence phenotypes, we performed microarrays in order to define the regulon of the Cpx TCS. We detected 393 genes differentially regulated in the ΔcpxRA strain. The gene expression profile of the ΔnlpE strain is strikingly different than the profile of ΔcpxRA with regards to the genes activated by CpxRA. Further, there is no clear inverse correlation in the expression pattern of the ΔcpxP strain in comparison to ΔcpxRA. Taken together, these data suggest that in these conditions, CpxRA activates gene expression in a largely NlpE- and CpxP-independent manner. Compared to wildtype, 161 genes were downregulated in the ΔcpxRA strain, while being upregulated or unchanged in the Cpx auxiliary protein deletion strains. This group of genes, which we hypothesize may contribute to the loss of virulence of ΔcpxRA, includes T6SS components, ompF, the regulator for colanic acid synthesis, and several genes involved in maltose metabolism.
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Affiliation(s)
| | - Nilmini Mendis
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Lei Zhu
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Samantha Gruenheid
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Sebastien P Faucher
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Hervé Le Moual
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
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Yin K, Guan Y, Ma R, Wei L, Liu B, Liu X, Zhou X, Ma Y, Zhang Y, Waldor MK, Wang Q. Critical role for a promoter discriminator in RpoS control of virulence in Edwardsiella piscicida. PLoS Pathog 2018; 14:e1007272. [PMID: 30169545 PMCID: PMC6136808 DOI: 10.1371/journal.ppat.1007272] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/13/2018] [Accepted: 08/09/2018] [Indexed: 12/11/2022] Open
Abstract
Edwardsiella piscicida is a leading fish pathogen that causes significant economic loses in the aquaculture industry. The pathogen depends on type III and type VI secretion systems (T3/T6SS) for growth and virulence in fish and the expression of both systems is controlled by the EsrB transcription activator. Here, we performed a Tn-seq-based screen to uncover factors that govern esrB expression. Unexpectedly, we discovered that RpoS antagonizes esrB expression and thereby inhibits production of E. piscicida’s T3/T6SS. Using in vitro transcription assays, we showed that RpoS can block RpoD-mediated transcription of esrB. ChIP-seq- and RNA-seq-based profiling, as well as mutational and biochemical analyses revealed that RpoS-repressed promoters contain a -6G in their respective discriminator sequences; moreover, this -6G proved critical for RpoS to inhibit esrB expression. Mutation of the RpoS R99 residue, an amino acid that molecular modeling predicts interacts with -6G in the esrB discriminator, abolished RpoS’ capacity for repression. In a turbot model, an rpoS deletion mutant was attenuated early but not late in infection, whereas a mutant expressing RpoSR99A exhibited elevated fitness throughout the infection period. Collectively, these findings deepen our understanding of how RpoS can inhibit gene expression and demonstrate the temporal variation in the requirement for this sigma factor during infection. Edwardsiella piscicida, a major fish pathogen, relies on T3/T6SSs for virulence and the EsrB transcription activator promotes the expression of these secretion systems and many other genes that enable growth in fish. Here, we found that the alternative sigma factor RpoS inhibits expression of esrB thereby diminishing expression of virulence-associated genes. Transcriptome profiling revealed that, as in many other organisms, RpoS enables expression of hundreds of genes, many of which are linked to stress responses, suggesting that RpoS may mediate a trade-off between stress adaptation and virulence. Consistent with this idea, we found that an rpoS mutant was attenuated early, but not late in infection of turbot, whereas an esrB mutant was attenuated late and not early in infection. Molecular analyses demonstrated that RpoS inhibition of esrB expression involves a direct interaction between RpoS and the esrB promoter; in particular, interactions between RpoS residue R99 and the -6G nucleotide in the esrB promoter discriminator appear to be critical for repression of esrB expression. These findings provide new insight into how a sigma factor can impede transcription and demonstrate the temporal dynamics of the requirement for a sigma factor during the course of infection.
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Affiliation(s)
- Kaiyu Yin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, East China University of Science and Technology, Shanghai, China
| | - Yunpeng Guan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Ruiqing Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Lifan Wei
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Bing Liu
- Institut de Biotecnologia i Biomedicina, Dept. de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Xiaohong Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Xiangshan Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yue Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, East China University of Science and Technology, Shanghai, China
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, East China University of Science and Technology, Shanghai, China
| | - Matthew K. Waldor
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Division of Infectious Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, East China University of Science and Technology, Shanghai, China
- * E-mail:
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Abstract
σN (also σ54) is an alternative sigma factor subunit of the RNA polymerase complex that regulates the expression of genes from many different ontological groups. It is broadly conserved in the Eubacteria with major roles in nitrogen metabolism, membrane biogenesis, and motility. σN is encoded as the first gene of a five-gene operon including rpoN (σN), ptsN, hpf, rapZ, and npr that has been genetically retained among species of Escherichia, Shigella, and Salmonella. In an increasing number of bacteria, σN has been implicated in the control of genes essential to pathogenic behavior, including those involved in adherence, secretion, immune subversion, biofilm formation, toxin production, and resistance to both antimicrobials and biological stressors. For most pathogens how this is achieved is unknown. In enterohemorrhagic Escherichia coli (EHEC) O157, Salmonella enterica, and Borrelia burgdorferi, regulation of virulence by σN requires another alternative sigma factor, σS, yet the model by which σN-σS virulence regulation is predicted to occur is varied in each of these pathogens. In this review, the importance of σN to bacterial pathogenesis is introduced, and common features of σN-dependent virulence regulation discussed. Emphasis is placed on the molecular mechanisms underlying σN virulence regulation in E. coli O157. This includes a review of the structure and function of regulatory pathways connecting σN to virulence expression, predicted input signals for pathway stimulation, and the role for cognate σN activators in initiation of gene systems determining pathogenic behavior.
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Krause M, Barth H, Schmidt H. Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli. Toxins (Basel) 2018; 10:toxins10060241. [PMID: 29903982 PMCID: PMC6024878 DOI: 10.3390/toxins10060241] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/07/2018] [Accepted: 06/12/2018] [Indexed: 12/16/2022] Open
Abstract
Studies on Shiga toxin-producing Escherichia coli (STEC) typically examine and classify the virulence gene profiles based on genomic analyses. Among the screened strains, a subgroup of STEC which lacks the locus of enterocyte effacement (LEE) has frequently been identified. This raises the question about the level of pathogenicity of such strains. This review focuses on the advantages and disadvantages of the standard screening procedures in virulence profiling and summarizes the current knowledge concerning the function and regulation of toxins encoded by LEE-negative STEC. Although LEE-negative STEC usually come across as food isolates, which rarely cause infections in humans, some serotypes have been implicated in human diseases. In particular, the LEE-negative E. coli O104:H7 German outbreak strain from 2011 and the Australian O113:H21 strain isolated from a HUS patient attracted attention. Moreover, the LEE-negative STEC O113:H21 strain TS18/08 that was isolated from minced meat is remarkable in that it not only encodes multiple toxins, but in fact expresses three different toxins simultaneously. Their characterization contributes to understanding the virulence of the LEE-negative STEC.
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Affiliation(s)
- Maike Krause
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany.
| | - Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Herbert Schmidt
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany.
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Shaw JA, Henard CA, Liu L, Dieckman LM, Vázquez-Torres A, Bourret TJ. Salmonella enterica serovar Typhimurium has three transketolase enzymes contributing to the pentose phosphate pathway. J Biol Chem 2018; 293:11271-11282. [PMID: 29848552 DOI: 10.1074/jbc.ra118.003661] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/23/2018] [Indexed: 11/06/2022] Open
Abstract
The genus Salmonella is responsible for many illnesses in humans and other vertebrate animals. We report here that Salmonella enterica serovar Typhimurium harbors three transketolases that support the non-oxidative branch of the pentose phosphate pathway. BLAST analysis identified two genes, STM14_2885 and STM14_2886, that together encode a putative transketolase (TktC) with 46-47% similarity to the known TktA and TktB isoforms. Assessing the mRNA and protein expression for each of the three transketolases, we determined that all are expressed in WT cells and regulated to varying extents by the alternative sigma factor RpoS. Enzyme assays with lysates from WT and transketolase-knockout strains established that TktA is responsible for >88% of the transketolase activity in WT cells. We purified recombinant forms of each isoenzyme to assess the kinetics for canonical transketolase reactions. TktA and TktB had comparable values for Vmax (539-1362 μm NADH consumed/s), Km (80-739 μm), and catalytic efficiency (1.02 × 108-1.06 × 109 m-1/s) for each substrate tested. The recombinant form of TktC had lower Km values (23-120 μm), whereas the Vmax (7.8-16 μm NADH consumed/s) and catalytic efficiency (5.58 × 106 to 6.07 × 108 m-1/s) were 10-100-fold lower. Using a murine model of Salmonella infection, we showed that a strain lacking all three transketolases is avirulent in C57BL/6 mice. These data provide evidence that S Typhimurium possesses three transketolases that contribute to pathogenesis.
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Affiliation(s)
- Jeff A Shaw
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska 68178
| | - Calvin A Henard
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80011
| | - Lin Liu
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80011
| | - Lynne M Dieckman
- Department of Chemistry, Creighton University, Omaha, Nebraska 68178
| | - Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80011; Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80220
| | - Travis J Bourret
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska 68178.
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Mendez J, Cascales D, Garcia-Torrico AI, Guijarro JA. Temperature-Dependent Gene Expression in Yersinia ruckeri: Tracking Specific Genes by Bioluminescence During in Vivo Colonization. Front Microbiol 2018; 9:1098. [PMID: 29887855 PMCID: PMC5981175 DOI: 10.3389/fmicb.2018.01098] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 05/08/2018] [Indexed: 11/26/2022] Open
Abstract
Yersinia ruckeri is a bacterium causing fish infection processes at temperatures below the optimum for growth. A derivative Tn5 transposon was used to construct a library of Y. ruckeri mutants with transcriptional fusions between the interrupted genes and the promoterless luxCDABE and lacZY operons. In vitro analysis of β-galactosidase activity allowed the identification of 168 clones having higher expression at 18°C than at 28°C. Among the interrupted genes a SAM-dependent methyltransferase, a diguanylated cyclase, three genes involved in legionaminic acid synthesis and three transcriptional regulators were defined. In order to determine, via bioluminescence emission, the in vivo expression of some of these genes, two of the selected mutants were studied. In one of them, the acrR gene coding a repressor involved in regulation of the AcrAB-TolC expulsion pump was interrupted. This mutant was found to be highly resistant to compounds such as chloramphenicol, tetracycline, and ciprofloxacin. Although acrR mutation was not related to virulence in Y. ruckeri, this mutant was useful to analyze acrR expression in fish tissues in vivo. The other gene studied was osmY which is activated under osmotic stress and is involved in virulence. In this case, complemented mutant was used for experiments with fish. In vivo analysis of bioluminescence emission by these two strains showed higher values for acrR in gut, liver and adipose tissue, whereas osmY showed higher luminescence in gut and, at the end of the infection process, in muscle tissue. Similar results were obtained in ex vivo assays using rainbow trout tissues. The results indicated that this kind of approach was useful for the identification of genes related to virulence in Y. ruckeri and also for the in vivo and in vitro studies of each of the selected genes.
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Affiliation(s)
- Jessica Mendez
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - Desirée Cascales
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - Ana I Garcia-Torrico
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, Oviedo, Spain
| | - Jose A Guijarro
- Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, Oviedo, Spain
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Role of RpoS in stress resistance, quorum sensing and spoilage potential of Pseudomonas fluorescens. Int J Food Microbiol 2018; 270:31-38. [DOI: 10.1016/j.ijfoodmicro.2018.02.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/04/2018] [Accepted: 02/11/2018] [Indexed: 01/02/2023]
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Nazir F, Ibrahim M, Zaman G, Hussain A, Yar AM, Bo Z. Genetic Diversity and Functional Analysis of Sigma Factors in Enterobacter cloacae Complex Resourced From Various Niche. Evol Bioinform Online 2018; 14:1176934318754878. [PMID: 29472760 PMCID: PMC5808824 DOI: 10.1177/1176934318754878] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/02/2018] [Indexed: 11/16/2022] Open
Abstract
Sigma factors are bacterial transcription factors that bind the core RNA polymerase and direct transcription initiation at a specific promoter site. These specialized sigma factors bind the promoters of genes appropriate to the environmental conditions and selectively increase the transcription of those genes. Here, we attempt to identify sigma factors in 5 genomes belonging to the Enterobacter cloacae complex (Ecc), a group of gram-negative bacteria that are important nosocomial pathogens. This process includes the identification of orthologous sequences, conserved motifs, domains, families, phylogenetic profiles, and protein-protein associations of these components. Based on the reference genome, genome-wide comparison revealed that the genomes of Enterobacter asburiae JCM6051, Enterobacter nimipressuralis CIP 104980, Enterobacter hormaechei ATCC49162, Enterobacter kobei JCM 8580, and Enterobacter ludwigii EN-119 encode 10 sigma factors that exist in the reference strain Enterobacter cloacae subsp cloacae ATCC13047. Moreover, the sequence similarity, protein domains and families of the sigma factors, protein-protein association, and phylogenetic profile indicate that the sigma factor proteins of these 5 strains may have evolutionary relatedness and functional characteristics important to their various environmental niches. Interestingly, the absence of RpoS in E kobei, which contributes to bacterial survival under environmental stress conditions, indicates that RpoS might have been independently acquired and may play different roles relating to pathogenicity, host range determination, and/or niche adaptation. Future work such as RNA sequencing will be directed towards investigating the roles that these sigma factors play in the biology of the Ecc.
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Affiliation(s)
- Farah Nazir
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Genomics and Computational Biology Laboratory, Department of Biosciences, COMSATS Institute of Information Technology, Sahiwal, Pakistan
| | - Muhammad Ibrahim
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Genomics and Computational Biology Laboratory, Department of Biosciences, COMSATS Institute of Information Technology, Sahiwal, Pakistan
| | - Ghunva Zaman
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Annam Hussain
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Asma Muhammad Yar
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhu Bo
- Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, China
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Investigation of host-pathogen interaction between Burkholderia pseudomallei and autophagy-related protein LC3 using hydrophobic chromatography-based technique. Cell Biosci 2017; 7:45. [PMID: 28852470 PMCID: PMC5567900 DOI: 10.1186/s13578-017-0172-4] [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: 06/16/2017] [Accepted: 08/17/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Burkholderia pseudomallei is an intracellular bacteria causing Melioidosis, the disease widely disseminates in Southeast Asia and Northern Australia. B. pseudomallei has ability to invade various types of host cell and to interfere with host defense mechanisms, such as nitric oxide (NO). Due to the cross-talk among alternative killing mechanisms in host immune response against invading microbes, autophagy is the molecular mechanism belonging to intracellular elimination of eukaryotic cells that has been widely discussed. However, bacterial evasion strategy of B. pseudomallei and host-bacterial protein-protein interaction within autophagic machinery remain unknown. METHODS Here, we demonstrated the protein-protein interaction study between different strains of B. pseudomallei, including wild type PP844 and rpoS mutant, with autophagy-related protein LC3 that has been constructed, using the modified immunoaffinity hydrophobic chromatography based-technique. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis was utilized for identifying the eluted proteins obtained from the established column. In addition, the expression level of gene encoding candidate protein was predicted prior to verification using real-time quantitative reverse transcription PCR assay (RT-qPCR). RESULTS LC3 recombinant proteins could be entrapped inside the column before encountering their bacterial interacting partners. Based on affinity interaction, the binding capacity of LC3 with antibody displayed over 50% readily for hydrophobically binding with bacterial proteins. Following protein identification, bacterial ATP-binding cassette (ABC) transporter periplasmic substrate-binding protein (BPSL2203) was identified as a candidate LC3-interacting protein, which was found only in B. pseudomallei wild type. Gene expression analysis and bioinformatics of BPSL2203 were validated the proteomic result which are suggesting the role of RpoS-dependent gene regulation. CONCLUSIONS Remarkably, utilization of the modified immunoaffinity hydrophobic chromatography with LC-MS/MS is a convenient and reliable approach to a study in B. pseudomallei-LC3 protein-protein interaction.
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Type VI secretion system contributes to Enterohemorrhagic Escherichia coli virulence by secreting catalase against host reactive oxygen species (ROS). PLoS Pathog 2017; 13:e1006246. [PMID: 28288207 PMCID: PMC5363993 DOI: 10.1371/journal.ppat.1006246] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 03/23/2017] [Accepted: 02/16/2017] [Indexed: 01/19/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is one major type of contagious and foodborne pathogens. The type VI secretion system (T6SS) has been shown to be involved in the bacterial pathogenicity and bacteria-bacteria competition. Here, we show that EHEC could secrete a novel effector KatN, a Mn-containing catalase, in a T6SS-dependent manner. Expression of katN is promoted by RpoS and OxyR and repressed by H-NS, and katN contributes to bacterial growth under oxidative stress in vitro. KatN could be secreted into host cell cytosol after EHEC is phagocytized by macrophage, which leads to decreased level of intracellular reactive oxygen species (ROS) and facilitates the intramacrophage survival of EHEC. Finally, animal model results show that the deletion mutant of T6SS was attenuated in virulence compared with the wild type strain, while the deletion mutant of katN had comparable virulence to the wild type strain. Taken together, our findings suggest that EHEC could sense oxidative stress in phagosome and decrease the host cell ROS by secreting catalase KatN to facilitate its survival in the host cells.
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45
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Guilhen C, Charbonnel N, Parisot N, Gueguen N, Iltis A, Forestier C, Balestrino D. Transcriptional profiling of Klebsiella pneumoniae defines signatures for planktonic, sessile and biofilm-dispersed cells. BMC Genomics 2016; 17:237. [PMID: 26979871 PMCID: PMC4791964 DOI: 10.1186/s12864-016-2557-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 02/29/2016] [Indexed: 12/22/2022] Open
Abstract
Background Surface-associated communities of bacteria, known as biofilms, play a critical role in the persistence and dissemination of bacteria in various environments. Biofilm development is a sequential dynamic process from an initial bacterial adhesion to a three-dimensional structure formation, and a subsequent bacterial dispersion. Transitions between these different modes of growth are governed by complex and partially known molecular pathways. Results Using RNA-seq technology, our work provided an exhaustive overview of the transcriptomic behavior of the opportunistic pathogen Klebsiella pneumoniae derived from free-living, biofilm and biofilm-dispersed states. For each of these conditions, the combined use of Z-scores and principal component analysis provided a clear illustration of distinct expression profiles. In particular, biofilm-dispersed cells appeared as a unique stage in the bacteria lifecycle, different from both planktonic and sessile states. The K-means cluster analysis showed clusters of Coding DNA Sequences (CDS) and non-coding RNA (ncRNA) genes differentially transcribed between conditions. Most of them included dominant functional classes, emphasizing the transcriptional changes occurring in the course of K. pneumoniae lifestyle transitions. Furthermore, analysis of the whole transcriptome allowed the selection of an overall of 40 transcriptional signature genes for the five bacterial physiological states. Conclusions This transcriptional study provides additional clues to understand the key molecular mechanisms involved in the transition between biofilm and the free-living lifestyles, which represents an important challenge to control both beneficial and harmful biofilm. Moreover, this exhaustive study identified physiological state specific transcriptomic reference dataset useful for the research community. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2557-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Cyril Guilhen
- Laboratoire Microorganismes: Génome Environnement, UMR CNRS 6023, Université d'Auvergne, Clermont Ferrand, F-63001, France
| | - Nicolas Charbonnel
- Laboratoire Microorganismes: Génome Environnement, UMR CNRS 6023, Université d'Auvergne, Clermont Ferrand, F-63001, France
| | - Nicolas Parisot
- UMR 203 BF2I, Biologie Fonctionnelle Insectes et Interactions, INRA, INSA de Lyon, Université de Lyon, F-69621, Villeurbanne, France
| | - Nathalie Gueguen
- Laboratoire Microorganismes: Génome Environnement, UMR CNRS 6023, Université d'Auvergne, Clermont Ferrand, F-63001, France
| | - Agnès Iltis
- Genostar, Montbonnot Saint Martin, F-38330, France
| | - Christiane Forestier
- Laboratoire Microorganismes: Génome Environnement, UMR CNRS 6023, Université d'Auvergne, Clermont Ferrand, F-63001, France
| | - Damien Balestrino
- Laboratoire Microorganismes: Génome Environnement, UMR CNRS 6023, Université d'Auvergne, Clermont Ferrand, F-63001, France.
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Wasfi R, Elkhatib WF, Khairalla AS. Effects of Selected Egyptian Honeys on the Cellular Ultrastructure and the Gene Expression Profile of Escherichia coli. PLoS One 2016; 11:e0150984. [PMID: 26954570 PMCID: PMC4783026 DOI: 10.1371/journal.pone.0150984] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 02/21/2016] [Indexed: 01/22/2023] Open
Abstract
The purpose of this study was to: (i) evaluate the antibacterial activities of three Egyptian honeys collected from different floral sources (namely, citrus, clover, and marjoram) against Escherichia coli; (ii) investigate the effects of these honeys on bacterial ultrastructure; and (iii) assess the anti-virulence potential of these honeys, by examining their impacts on the expression of eight selected genes (involved in biofilm formation, quorum sensing, and stress survival) in the test organism. The minimum inhibitory concentration (MIC) of the honey samples against E. coli ATCC 8739 were assessed by the broth microdilution assay in the presence and absence of catalase enzyme. Impacts of the honeys on the cellular ultrastructure and the expression profiles of the selected genes of E. coli were examined using transmission electron microscopy (TEM) and quantitative real-time polymerase chain reaction (qPCR) analysis, respectively. The susceptibility tests showed promising antibacterial activities of all the tested honeys against E. coli. This was supported by the TEM observations, which revealed “ghost” cells lacking DNA, in addition to cells with increased vacuoles, and/or with irregular shrunken cytoplasm. Among the tested honeys, marjoram exhibited the highest total antibacterial activity and the highest levels of peroxide-dependent activity. The qPCR analysis showed that all honey-treated cells share a similar overall pattern of gene expression, with a trend toward reduced expression of the virulence genes of interest. Our results indicate that some varieties of the Egyptian honey have the potential to be effective inhibitor and virulence modulator of E. coli via multiple molecular targets.
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Affiliation(s)
- Reham Wasfi
- Department of Microbiology & Immunology, Faculty of Pharmacy, October University for Modern Sciences and Arts (MSA), Giza, Egypt
| | - Walid F. Elkhatib
- Department of Microbiology & Immunology, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Ahmed S. Khairalla
- Department of Microbiology & Immunology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, Egypt
- * E-mail:
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Ryan D, Pati NB, Ojha UK, Padhi C, Ray S, Jaiswal S, Singh GP, Mannala GK, Schultze T, Chakraborty T, Suar M. Global transcriptome and mutagenic analyses of the acid tolerance response of Salmonella enterica serovar Typhimurium. Appl Environ Microbiol 2015; 81:8054-65. [PMID: 26386064 PMCID: PMC4651094 DOI: 10.1128/aem.02172-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 09/01/2015] [Indexed: 01/18/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causative agents of food-borne bacterial gastroenteritis. Swift invasion through the intestinal tract and successful establishment in systemic organs are associated with the adaptability of S. Typhimurium to different stress environments. Low-pH stress serves as one of the first lines of defense in mammalian hosts, which S. Typhimurium must efficiently overcome to establish an infection. Therefore, a better understanding of the molecular mechanisms underlying the adaptability of S. Typhimurium to acid stress is highly relevant. In this study, we have performed a transcriptome analysis of S. Typhimurium under the acid tolerance response (ATR) and found a large number of genes (∼47%) to be differentially expressed (more than 1.5-fold or less than -1.5-fold; P < 0.01). Functional annotation revealed differentially expressed genes to be associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Additionally, our knockout analysis of a subset of differentially regulated genes facilitated the identification of proteins that contribute to S. Typhimurium ATR and virulence. Mutants lacking genes encoding the K(+) binding and transport protein KdpA, hypothetical protein YciG, the flagellar hook cap protein FlgD, and the nitrate reductase subunit NarZ were significantly deficient in their ATRs and displayed varied in vitro virulence characteristics. This study offers greater insight into the transcriptome changes of S. Typhimurium under the ATR and provides a framework for further research on the subject.
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Affiliation(s)
- Daniel Ryan
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | - Niladri Bhusan Pati
- Institute of Medical Microbiology, German Centre of Infection Research, Site Giessen-Marburg-Langen, Justus-Liebig-University Giessen, Giessen, Germany
| | - Urmesh K Ojha
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | | | - Shilpa Ray
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | - Sangeeta Jaiswal
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | - Gajinder P Singh
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
| | - Gopala K Mannala
- Institute of Medical Microbiology, German Centre of Infection Research, Site Giessen-Marburg-Langen, Justus-Liebig-University Giessen, Giessen, Germany
| | - Tilman Schultze
- Institute of Medical Microbiology, German Centre of Infection Research, Site Giessen-Marburg-Langen, Justus-Liebig-University Giessen, Giessen, Germany
| | - Trinad Chakraborty
- Institute of Medical Microbiology, German Centre of Infection Research, Site Giessen-Marburg-Langen, Justus-Liebig-University Giessen, Giessen, Germany
| | - Mrutyunjay Suar
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India
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Ye Y, Gao J, Jiao R, Li H, Wu Q, Zhang J, Zhong X. The Membrane Proteins Involved in Virulence of Cronobacter sakazakii Virulent G362 and Attenuated L3101 Isolates. Front Microbiol 2015; 6:1238. [PMID: 26617581 PMCID: PMC4637405 DOI: 10.3389/fmicb.2015.01238] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 10/26/2015] [Indexed: 11/13/2022] Open
Abstract
Cronobacter sakazakii is an opportunistic foodborne pathogen and the virulence differences were previously documented. However, information about membranous proteins involved in virulence differences was not available. In this study, virulent characterization such as biofilm formation and flagella motility between virulent C. sakazakii isolate G362 and attenuated L3101 were determined. Then, two-dimensional gel electrophoresis (2-DE) technology was used to preliminarily reveal differential expression of membranous proteins between G362 and L3101. On the mass spectrometry (MS) analysis and MASCOT research results, fourteen proteins with differential expression were successfully identified. At the threshold of twofold changes, five out of eight membranous proteins were up-regulated in G362. Using RT-PCR, the expression abundance of the protein (enzV, ompX, lptE, pstB, and OsmY) genes at mRNA levels was consistent with the results by 2-DE method. The findings presented here provided novel information and valuable knowledge for revealing pathogenic mechanism of C. sakazakii.
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Affiliation(s)
- YingWang Ye
- School of Biotechnology and Food Engineering, Hefei University of Technology Hefei, China ; State Key Laboratory of Applied Microbiology Southern China Guangzhou, China ; Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application Guangzhou, China ; Guangdong Institute of Microbiology Guangzhou, China
| | - Jina Gao
- School of Biotechnology and Food Engineering, Hefei University of Technology Hefei, China
| | - Rui Jiao
- School of Biotechnology and Food Engineering, Hefei University of Technology Hefei, China
| | - Hui Li
- School of Biotechnology and Food Engineering, Hefei University of Technology Hefei, China ; State Key Laboratory of Applied Microbiology Southern China Guangzhou, China ; Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application Guangzhou, China ; Guangdong Institute of Microbiology Guangzhou, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology Southern China Guangzhou, China ; Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application Guangzhou, China ; Guangdong Institute of Microbiology Guangzhou, China
| | - Jumei Zhang
- State Key Laboratory of Applied Microbiology Southern China Guangzhou, China ; Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application Guangzhou, China ; Guangdong Institute of Microbiology Guangzhou, China
| | - Xian Zhong
- State Key Laboratory of Applied Microbiology Southern China Guangzhou, China ; Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application Guangzhou, China ; Guangdong Institute of Microbiology Guangzhou, China
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Fuentes DN, Calderón PF, Acuña LG, Rodas PI, Paredes-Sabja D, Fuentes JA, Gil F, Calderón IL. Motility modulation by the small non-coding RNA SroC inSalmonellaTyphimurium. FEMS Microbiol Lett 2015; 362:fnv135. [DOI: 10.1093/femsle/fnv135] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2015] [Indexed: 12/14/2022] Open
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50
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Connolly JPR, Finlay BB, Roe AJ. From ingestion to colonization: the influence of the host environment on regulation of the LEE encoded type III secretion system in enterohaemorrhagic Escherichia coli. Front Microbiol 2015; 6:568. [PMID: 26097473 PMCID: PMC4456613 DOI: 10.3389/fmicb.2015.00568] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/24/2015] [Indexed: 12/21/2022] Open
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) binds to host tissue and intimately attaches to intestinal cells using a dedicated type III secretion system (T3SS). This complex multi-protein organelle is encoded within a large pathogenicity island called the locus of enterocyte effacement (LEE), which is subject to extensive regulatory control. Over the past 15 years we have gained a wealth of knowledge concerning how the LEE is regulated transcriptionally by specific, global and phage encoded regulators. More recently, significant advances have been made in our understanding of how specific signals, including host or microbiota derived metabolic products and various nutrient sources, can affect how the LEE-encoded T3SS is regulated. In this review we discuss regulation of the LEE, focusing on how these physiologically relevant signals are sensed and how they affect the expression of this major virulence factor. The implications for understanding the disease process by specific regulatory mechanisms are also discussed.
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Affiliation(s)
- James P R Connolly
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow , Glasgow, UK
| | - B Brett Finlay
- Michael Smith Laboratories, University of British Columbia , Vancouver, BC, Canada
| | - Andrew J Roe
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow , Glasgow, UK
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