101
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Coulthurst S. The Type VI secretion system: a versatile bacterial weapon. Microbiology (Reading) 2019; 165:503-515. [DOI: 10.1099/mic.0.000789] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Sarah Coulthurst
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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102
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Abstract
The Type VI secretion system (T6SS) is a protein nanomachine that is widespread in Gram-negative bacteria and is used to translocate effector proteins directly into neighbouring cells. It represents a versatile bacterial weapon that can deliver effectors into distinct classes of target cells, playing key roles in inter-bacterial competition and bacterial interactions with eukaryotic cells. This versatility is underpinned by the ability of the T6SS to deliver a vast array of effector proteins, with many distinct activities and modes of interaction with the secretion machinery. Recent work has highlighted the importance and diversity of interactions mediated by T6SSs within polymicrobial communities, and offers new molecular insights into effector delivery and action in target cells.
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Affiliation(s)
- Sarah Coulthurst
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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103
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Young D, Pedre B, Ezeriņa D, De Smet B, Lewandowska A, Tossounian MA, Bodra N, Huang J, Astolfi Rosado L, Van Breusegem F, Messens J. Protein Promiscuity in H 2O 2 Signaling. Antioxid Redox Signal 2019; 30:1285-1324. [PMID: 29635930 DOI: 10.1089/ars.2017.7013] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
SIGNIFICANCE Decrypting the cellular response to oxidative stress relies on a comprehensive understanding of the redox signaling pathways stimulated under oxidizing conditions. Redox signaling events can be divided into upstream sensing of oxidants, midstream redox signaling of protein function, and downstream transcriptional redox regulation. Recent Advances: A more and more accepted theory of hydrogen peroxide (H2O2) signaling is that of a thiol peroxidase redox relay, whereby protein thiols with low reactivity toward H2O2 are instead oxidized through an oxidative relay with thiol peroxidases. CRITICAL ISSUES These ultrareactive thiol peroxidases are the upstream redox sensors, which form the first cellular port of call for H2O2. Not all redox-regulated interactions between thiol peroxidases and cellular proteins involve a transfer of oxidative equivalents, and the nature of redox signaling is further complicated through promiscuous functions of redox-regulated "moonlighting" proteins, of which the precise cellular role under oxidative stress can frequently be obscured by "polygamous" interactions. An ultimate goal of redox signaling is to initiate a rapid response, and in contrast to prokaryotic oxidant-responsive transcription factors, mammalian systems have developed redox signaling pathways, which intersect both with kinase-dependent activation of transcription factors, as well as direct oxidative regulation of transcription factors through peroxiredoxin (Prx) redox relays. FUTURE DIRECTIONS We highlight that both transcriptional regulation and cell fate can be modulated either through oxidative regulation of kinase pathways, or through distinct redox-dependent associations involving either Prxs or redox-responsive moonlighting proteins with functional promiscuity. These protein associations form systems of crossregulatory networks with multiple nodes of potential oxidative regulation for H2O2-mediated signaling.
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Affiliation(s)
- David Young
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Brandan Pedre
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Daria Ezeriņa
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Barbara De Smet
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Aleksandra Lewandowska
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Maria-Armineh Tossounian
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Nandita Bodra
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Jingjing Huang
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Leonardo Astolfi Rosado
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Frank Van Breusegem
- 2 Brussels Center for Redox Biology, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Joris Messens
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
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104
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The stringent response factor, RelA, positively regulates T6SS4 expression through the RovM/RovA pathway in Yersinia pseudotuberculosis. Microbiol Res 2019; 220:32-41. [DOI: 10.1016/j.micres.2018.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/31/2018] [Accepted: 12/06/2018] [Indexed: 12/13/2022]
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105
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Differential Gene Expression Patterns of Yersinia pestis and Yersinia pseudotuberculosis during Infection and Biofilm Formation in the Flea Digestive Tract. mSystems 2019; 4:mSystems00217-18. [PMID: 30801031 PMCID: PMC6381227 DOI: 10.1128/msystems.00217-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/27/2019] [Indexed: 01/01/2023] Open
Abstract
Yersinia pestis, the etiologic agent of plague, emerged as a fleaborne pathogen only within the last 6,000 years. Just five simple genetic changes in the Yersinia pseudotuberculosis progenitor, which served to eliminate toxicity to fleas and to enhance survival and biofilm formation in the flea digestive tract, were key to the transition to the arthropodborne transmission route. To gain a deeper understanding of the genetic basis for the development of a transmissible biofilm infection in the flea foregut, we evaluated additional gene differences and performed in vivo transcriptional profiling of Y. pestis, a Y. pseudotuberculosis wild-type strain (unable to form biofilm in the flea foregut), and a Y. pseudotuberculosis mutant strain (able to produce foregut-blocking biofilm in fleas) recovered from fleas 1 day and 14 days after an infectious blood meal. Surprisingly, the Y. pseudotuberculosis mutations that increased c-di-GMP levels and enabled biofilm development in the flea did not change the expression levels of the hms genes responsible for the synthesis and export of the extracellular polysaccharide matrix required for mature biofilm formation. The Y. pseudotuberculosis mutant uniquely expressed much higher levels of Yersinia type VI secretion system 4 (T6SS-4) in the flea, and this locus was required for flea blockage by Y. pseudotuberculosis but not for blockage by Y. pestis. Significant differences between the two species in expression of several metabolism genes, the Psa fimbrial genes, quorum sensing-related genes, transcription regulation genes, and stress response genes were evident during flea infection. IMPORTANCE Y. pestis emerged as a highly virulent, arthropod-transmitted pathogen on the basis of relatively few and discrete genetic changes from Y. pseudotuberculosis. Parallel comparisons of the in vitro and in vivo transcriptomes of Y. pestis and two Y. pseudotuberculosis variants that produce a nontransmissible infection and a transmissible infection of the flea vector, respectively, provided insights into how Y. pestis has adapted to life in its flea vector and point to evolutionary changes in the regulation of metabolic and biofilm development pathways in these two closely related species.
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106
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Lonergan ZR, Nairn BL, Wang J, Hsu YP, Hesse LE, Beavers WN, Chazin WJ, Trinidad JC, VanNieuwenhze MS, Giedroc DP, Skaar EP. An Acinetobacter baumannii, Zinc-Regulated Peptidase Maintains Cell Wall Integrity during Immune-Mediated Nutrient Sequestration. Cell Rep 2019; 26:2009-2018.e6. [PMID: 30784584 PMCID: PMC6441547 DOI: 10.1016/j.celrep.2019.01.089] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/21/2018] [Accepted: 01/24/2019] [Indexed: 01/10/2023] Open
Abstract
Acinetobacter baumannii is an important nosocomial pathogen capable of causing wound infections, pneumonia, and bacteremia. During infection, A. baumannii must acquire Zn to survive and colonize the host. Vertebrates have evolved mechanisms to sequester Zn from invading pathogens by a process termed nutritional immunity. One of the most upregulated genes during Zn starvation encodes a putative cell wall-modifying enzyme which we named ZrlA. We found that inactivation of zrlA diminished growth of A. baumannii during Zn starvation. Additionally, this mutant strain displays increased cell envelope permeability, decreased membrane barrier function, and aberrant peptidoglycan muropeptide abundances. This altered envelope increases antibiotic efficacy both in vitro and in an animal model of A. baumannii pneumonia. These results establish ZrlA as a crucial link between nutrient metal uptake and cell envelope homeostasis during A. baumannii pathogenesis, which could be targeted for therapeutic development.
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Affiliation(s)
- Zachery R Lonergan
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Microbe-Host Interactions Training Program, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Brittany L Nairn
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jiefei Wang
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - Yen-Pang Hsu
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Laura E Hesse
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Microbe-Host Interactions Training Program, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - William N Beavers
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Walter J Chazin
- Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Chemistry, Vanderbilt University, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jonathan C Trinidad
- Department of Chemistry, Indiana University, Bloomington, IN, USA; Laboratory for Biological Mass Spectrometry, Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - Michael S VanNieuwenhze
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - David P Giedroc
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
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107
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Lennings J, West TE, Schwarz S. The Burkholderia Type VI Secretion System 5: Composition, Regulation and Role in Virulence. Front Microbiol 2019; 9:3339. [PMID: 30687298 PMCID: PMC6335564 DOI: 10.3389/fmicb.2018.03339] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 12/24/2018] [Indexed: 12/19/2022] Open
Abstract
The soil saprophyte and Tier I select agent Burkholderia pseudomallei can cause rapidly fatal infections in humans and animals. The capability of switching to an intracellular life cycle during infection appears to be a decisive trait of B. pseudomallei for causing disease. B. pseudomallei harbors multiple type VI secretion systems (T6SSs) orthologs of which are present in the surrogate organism Burkholderia thailandensis. Upon host cell entry and vacuolar escape into the cytoplasm, B. pseudomallei and B. thailandensis manipulate host cells by utilizing the T6SS-5 (also termed T6SS1) to form multinucleated giant cells for intercellular spread. Disruption of the T6SS-5 in B. thailandensis causes a drastic attenuation of virulence in wildtype but not in mice lacking the central innate immune adapter protein MyD88. This result suggests that the T6SS-5 is deployed by the bacteria to overcome innate immune responses. However, important questions in this field remain unsolved including the mechanism underlying T6SS-5 activity and its physiological role during infection. In this review, we summarize the current knowledge on the components and regulation of the T6SS-5 as well as its role in virulence in mammalian hosts.
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Affiliation(s)
- Jan Lennings
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - T Eoin West
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Washington, Seattle, WA, United States
| | - Sandra Schwarz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
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108
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Vonaesch P, Anderson M, Sansonetti PJ. Pathogens, microbiome and the host: emergence of the ecological Koch's postulates. FEMS Microbiol Rev 2018; 42:273-292. [PMID: 29325027 DOI: 10.1093/femsre/fuy003] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Indexed: 02/07/2023] Open
Abstract
Even though tremendous progress has been made in the last decades to elucidate the mechanisms of intestinal homeostasis, dysbiosis and disease, we are only at the beginning of understanding the complexity of the gut ecosystem and the underlying interaction networks. We are also only starting to unravel the mechanisms that pathogens have evolved to overcome the barriers imposed by the microbiota and host to exploit the system to their own benefit. Recent work in these domains clearly indicates that the 'traditional Koch's postulates', which state that a given pathogen leads to a distinct disease, are not valid for all 'infectious' diseases, but that a more complete and complex interpretation of Koch's postulates is needed in order to understand and explain them. This review summarises the current understanding of what defines a healthy gut ecosystem and highlights recent progress in uncovering the interplay between the host, its microbiota and invading intestinal pathogens. Based on these recent findings, we propose a new interpretation of Koch's postulates that we term 'ecological Koch's postulates'.
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Affiliation(s)
- Pascale Vonaesch
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 28 Rue du Dr. Roux, Paris 75015, France
| | - Mark Anderson
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 28 Rue du Dr. Roux, Paris 75015, France
| | - Philippe J Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 28 Rue du Dr. Roux, Paris 75015, France
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109
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Wang M, Cao H, Wang Q, Xu T, Guo X, Liu B. The Roles of Two Type VI Secretion Systems in Cronobacter sakazakii ATCC 12868. Front Microbiol 2018; 9:2499. [PMID: 30405562 PMCID: PMC6204376 DOI: 10.3389/fmicb.2018.02499] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 10/01/2018] [Indexed: 01/18/2023] Open
Abstract
The type VI secretion system (T6SS), which has been found in 25% of gram-negative bacteria, is a crucial virulence factor in several pathogens. Although T6SS gene loci have been discovered in Cronobacter species, one of the major opportunistic foodborne pathogens, its function has not been elucidated. In this study, the roles of two phylogenetically distinct T6SS gene clusters in Cronobacter sakazakii ATCC12868 were investigated. Analysis of 138 genome sequences of C. sakazakii strains, we found that one T6SS gene cluster (T6SS-1) was ubiquitous in all examined strains, whereas another (T6SS-2) was absent or degenerated in a large proportion of the strains (n = 97). In addition, we confirmed the T6SS-1 antibacterial function through an in-frame deletion in the vasK and hcp genes. Compared with the wild-type strain, the T6SS-2-deficient mutant presented a much stronger colonization of organs when infecting neonatal rats. Thus, we proposed that T6SS-2 plays a role in pathogenic processes. This is the first study to investigate the functions of T6SS in C. sakazakii, and the results will extend our understanding of the pathogenic and phylogenetic characteristics of C. sakazakii.
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Affiliation(s)
- Min Wang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China
| | - Hengchun Cao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China
| | - Qian Wang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China
| | - Tingting Xu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China
| | - Xi Guo
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China
| | - Bin Liu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Tianjin Economic-Technological Development Area, Nankai University, Tianjin, China
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110
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Noreen Z, Jobichen C, Abbasi R, Seetharaman J, Sivaraman J, Bokhari H. Structural basis for the pathogenesis of Campylobacter jejuni Hcp1, a structural and effector protein of the Type VI Secretion System. FEBS J 2018; 285:4060-4070. [PMID: 30194714 DOI: 10.1111/febs.14650] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/17/2018] [Accepted: 09/03/2018] [Indexed: 12/22/2022]
Abstract
The Type VI Secretion System (T6SS) provides enhanced virulence to Campylobacter jejuni and has been associated with a high incidence of bloody diarrhea. The hemolysin-coregulated protein (Hcp)-the hallmark of the T6SS-can act as a structural and effector protein. Unlike other T6SS-harboring bacteria, which possess multiple Hcp proteins each performing different functions, C. jejuni possesses only one Hcp protein, and its structural and functional role has not been elucidated previously. Here, we report the structure and functional studies of Hcp from C. jejuni. We found similarities between the hexameric ring structure of Hcp-Cj and that of Hcp3 from Pseudomonas aeruginosa. Through functional studies, we showed two roles for Hcp-Cj that is, in cytotoxicity toward HepG2 cells and in biofilm formation in C. jejuni. In structure-based mutational analyses, we showed that an Arg-to-Ala mutation at position 30 within the extended loop results in a significant decrease in cytotoxicity, suggesting a role for this loop in binding to the host cell. However, this mutation does not affect its biofilm formation function. Collectively, this study supports the dual role of Hcp-Cj as a structural and effector protein in C. jejuni.
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Affiliation(s)
- Zobia Noreen
- Department of Biosciences, COMSATS University, Islamabad Campus, Islamabad, Pakistan
| | - Chacko Jobichen
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Rashda Abbasi
- Institute of Biomedical and Genetic Engineering (IBGE), Islamabad, Pakistan
| | | | - J Sivaraman
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Habib Bokhari
- Department of Biosciences, COMSATS University, Islamabad Campus, Islamabad, Pakistan
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111
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Becker M, Patz S, Becker Y, Berger B, Drungowski M, Bunk B, Overmann J, Spröer C, Reetz J, Tchuisseu Tchakounte GV, Ruppel S. Comparative Genomics Reveal a Flagellar System, a Type VI Secretion System and Plant Growth-Promoting Gene Clusters Unique to the Endophytic Bacterium Kosakonia radicincitans. Front Microbiol 2018; 9:1997. [PMID: 30214433 PMCID: PMC6125372 DOI: 10.3389/fmicb.2018.01997] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 08/08/2018] [Indexed: 01/04/2023] Open
Abstract
The recent worldwide discovery of plant growth-promoting (PGP) Kosakonia radicincitans in a large variety of crop plants suggests that this species confers significant influence on plants, both in terms of yield increase and product quality improvement. We provide a comparative genome analysis which helps to unravel the genetic basis for K. radicincitans' motility, competitiveness and plant growth-promoting capacities. We discovered that K. radicincitans carries multiple copies of complex gene clusters, among them two flagellar systems and three type VI secretion systems (T6SSs). We speculate that host invasion may be facilitated by different flagella, and bacterial competitor suppression by effector proteins ejected via T6SSs. We found a large plasmid in K. radicincitans DSM 16656T, the species type strain, that confers the potential to exploit plant-derived carbon sources. We propose that multiple copies of complex gene clusters in K. radicincitans are metabolically expensive but provide competitive advantage over other bacterial strains in nutrient-rich environments. The comparison of the DSM 16656T genome to genomes of other genera of enteric plant growth-promoting bacteria (PGPB) exhibits traits unique to DSM 16656T and K. radicincitans, respectively, and traits shared between genera. We used the output of the in silico analysis for predicting the purpose of genomic features unique to K. radicincitans and performed microarray, PhyloChip, and microscopical analyses to gain deeper insight into the interaction of DSM 16656T, plants and associated microbiota. The comparative genome analysis will facilitate the future search for promising candidates of PGPB for sustainable crop production.
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Affiliation(s)
- Matthias Becker
- Leibniz Institute of Vegetable and Ornamental Crops, Grossbeeren, Germany
| | - Sascha Patz
- Leibniz Institute of Vegetable and Ornamental Crops, Grossbeeren, Germany.,Algorithms in Bioinformatics, Center for Bioinformatics, University of Tübingen, Tübingen, Germany
| | - Yvonne Becker
- Leibniz Institute of Vegetable and Ornamental Crops, Grossbeeren, Germany.,Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institute-Federal Research Centre for Cultivated Plants, Braunschweig, Germany
| | - Beatrice Berger
- Leibniz Institute of Vegetable and Ornamental Crops, Grossbeeren, Germany.,Institute for National and International Plant Health, Julius Kühn-Institute-Federal Research Centre for Cultivated Plants, Braunschweig, Germany
| | - Mario Drungowski
- Leibniz Institute of Vegetable and Ornamental Crops, Grossbeeren, Germany
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Jörg Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Cathrin Spröer
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Jochen Reetz
- Federal Institute for Risk Assessment, Berlin, Germany
| | | | - Silke Ruppel
- Leibniz Institute of Vegetable and Ornamental Crops, Grossbeeren, Germany
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112
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Yang X, Pan J, Wang Y, Shen X. Type VI Secretion Systems Present New Insights on Pathogenic Yersinia. Front Cell Infect Microbiol 2018; 8:260. [PMID: 30109217 PMCID: PMC6079546 DOI: 10.3389/fcimb.2018.00260] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/13/2018] [Indexed: 12/22/2022] Open
Abstract
The type VI secretion system (T6SS) is a versatile secretion system widely distributed in Gram-negative bacteria that delivers multiple effector proteins into either prokaryotic or eukaryotic cells, or into the extracellular milieu. T6SS participates in various physiological processes including bacterial competition, host infection, and stress response. Three pathogenic Yersinia species, namely Yersinia pestis, Yersinia pseudotuberculosis, and Yersinia enterocolitica, possess different copies of T6SSs with distinct biological functions. This review summarizes the pathogenic, antibacterial, and stress-resistant roles of T6SS in Yersinia and the ion-transporting ability in Y. pseudotuberculosis. In addition, the T6SS-related effectors and regulators identified in Yersinia are discussed.
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Affiliation(s)
- Xiaobing Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, China.,Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Junfeng Pan
- Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Yao Wang
- Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, China.,Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
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113
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Bobrov AG, Kirillina O, Fosso MY, Fetherston JD, Miller MC, VanCleave TT, Burlison JA, Arnold WK, Lawrenz MB, Garneau-Tsodikova S, Perry RD. Zinc transporters YbtX and ZnuABC are required for the virulence of Yersinia pestis in bubonic and pneumonic plague in mice. Metallomics 2018; 9:757-772. [PMID: 28540946 DOI: 10.1039/c7mt00126f] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A number of bacterial pathogens require the ZnuABC Zinc (Zn2+) transporter and/or a second Zn2+ transport system to overcome Zn2+ sequestration by mammalian hosts. Previously we have shown that in addition to ZnuABC, Yersinia pestis possesses a second Zn2+ transporter that involves components of the yersiniabactin (Ybt), siderophore-dependent iron transport system. Synthesis of the Ybt siderophore and YbtX, a member of the major facilitator superfamily, are both critical components of the second Zn2+ transport system. Here we demonstrate that a ybtX znu double mutant is essentially avirulent in mouse models of bubonic and pneumonic plague while a ybtX mutant retains high virulence in both plague models. While sequestration of host Zn is a key nutritional immunity factor, excess Zn appears to have a significant antimicrobial role in controlling intracellular bacterial survival. Here, we demonstrate that ZntA, a Zn2+ exporter, plays a role in resistance to Zn toxicity in vitro, but that a zntA zur double mutant retains high virulence in both pneumonic and bubonic plague models and survival in macrophages. We also confirm that Ybt does not directly bind Zn2+in vitro under the conditions tested. However, we detect a significant increase in Zn2+-binding ability of filtered supernatants from a Ybt+ strain compared to those from a strain unable to produce the siderophore, supporting our previously published data that Ybt biosynthetic genes are involved in the production of a secreted Zn-binding molecule (zincophore). Our data suggest that Ybt or a modified Ybt participate in or promote Zn-binding activity in culture supernatants and is involved in Zn acquisition in Y. pestis.
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Affiliation(s)
- Alexander G Bobrov
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY, USA.
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114
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Ugarte-Ruiz M, Domínguez L, Corcionivoschi N, Wren BW, Dorrell N, Gundogdu O. Exploring the oxidative, antimicrobial and genomic properties of Campylobacter jejuni strains isolated from poultry. Res Vet Sci 2018; 119:170-175. [PMID: 29957495 DOI: 10.1016/j.rvsc.2018.06.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 04/25/2018] [Accepted: 06/13/2018] [Indexed: 11/19/2022]
Abstract
Campylobacter jejuni is the leading cause of food-borne bacterial enteritis in humans, with contaminated poultry products considered the main source of infection. To survive the food chain, C. jejuni utilizes multiple defense mechanisms that counter oxidative and aerobic stresses. In this study, we phenotypically characterised 63 C. jejuni strains with oxidative stress survival and antimicrobial susceptibility testing to investigate correlations between these two phenotypes against the source of the strains and the presence of the MarR regulators RrpA and RrpB which have a role in regulating the response to oxidative and aerobic stress. C. jejuni strains isolated from meat and neck skin displayed the highest resistance to oxidative stress. In addition, C. jejuni strains that have an rrpA+rrpB- profile exhibit increased resistance to oxidative stress and to antimicrobials. Here we establish a preliminary link between the distribution of RrpA and RrpB and the increased resistance to antimicrobials. This study provides insight into how the genotypic make up of C. jejuni can influence the ability of the bacterium to survive within areas of high oxygen stress, such as the food chain, and subsequently can have a potential negative impact on human health.
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Affiliation(s)
- Maria Ugarte-Ruiz
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain.
| | - Lucas Domínguez
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain; Facultad de Veterinaria, Universidad Complutense Madrid, Madrid, Spain.
| | | | - Brendan W Wren
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
| | - Nick Dorrell
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
| | - Ozan Gundogdu
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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115
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The Type VI Secretion System Engages a Redox-Regulated Dual-Functional Heme Transporter for Zinc Acquisition. Cell Rep 2018; 20:949-959. [PMID: 28746878 DOI: 10.1016/j.celrep.2017.06.081] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/15/2017] [Accepted: 06/27/2017] [Indexed: 12/21/2022] Open
Abstract
The type VI secretion system was recently reported to be involved in zinc acquisition, but the underlying mechanism remains unclear. Here, we report that Burkholderia thailandensis T6SS4 is involved in zinc acquisition via secretion of a zinc-scavenging protein, TseZ, that interacts with the outer membrane heme transporter HmuR. We find that HmuR is a redox-regulated dual-functional transporter that transports heme iron under normal conditions but zinc upon sensing extracellular oxidative stress, triggered by formation of an intramolecular disulfide bond. Acting as the first line of defense against oxidative stress, HmuR not only guarantees an immediate response to the changing environment but also provides a fine-tuned mechanism that allows a gradual response to perceived stress. The T6SS/HmuR-mediated active zinc transport system is also involved in bacterial virulence and contact-independent bacterial competition. We describe a sophisticated bacterial zinc acquisition mechanism affording insights into the role of metal ion transport systems.
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116
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Effector⁻Immunity Pairs Provide the T6SS Nanomachine its Offensive and Defensive Capabilities. Molecules 2018; 23:molecules23051009. [PMID: 29701633 PMCID: PMC6099711 DOI: 10.3390/molecules23051009] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/13/2018] [Accepted: 04/23/2018] [Indexed: 01/23/2023] Open
Abstract
Type VI protein secretion systems (T6SSs) are specialized transport apparatus which can target both eukaryotic and prokaryotic cells and play key roles in host⁻pathogen⁻microbiota interactions. Therefore, T6SSs have attracted much attention as a research topic during the past ten years. In this review, we particularly summarized the T6SS antibacterial function, which involves an interesting offensive and defensive mechanism of the effector⁻immunity (E⁻I) pairs. The three main categories of effectors that target the cell wall, membranes, and nucleic acids during bacterial interaction, along with their corresponding immunity proteins are presented. We also discuss structural analyses of several effectors and E⁻I pairs, which explain the offensive and defensive mechanisms underpinning T6SS function during bacterial competition for niche-space, as well as the bioinformatics, proteomics, and protein⁻protein interaction (PPI) methods used to identify and characterize T6SS mediated E⁻I pairs. Additionally, we described PPI methods for verifying E⁻I pairs.
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117
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Dai Q, Xu L, Xiao L, Zhu K, Song Y, Li C, Zhu L, Shen X, Wang Y. RovM and CsrA Negatively Regulate Urease Expression in Yersinia pseudotuberculosis. Front Microbiol 2018; 9:348. [PMID: 29535702 PMCID: PMC5835112 DOI: 10.3389/fmicb.2018.00348] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 02/13/2018] [Indexed: 01/07/2023] Open
Abstract
Urease acts as an important acid resistance system and virulence factor that is widespread among microorganisms. RovM is a global regulator that regulates a series of genes and pathways including acid survival systems in the enteric bacterium Yersinia pseudotuberculosis (Yptb). However, whether RovM regulates the urease activity in Yptb was still unknown. In this study, by using qualitative and quantitative urease assays, we show that the urease expression responds to nutrient conditions and the RovM protein represses urease expression by binding to its promoter. A previously reported positive regulator OmpR activates urease activity but RovM plays a dominant role in different nutrient conditions. In addition, carbon storage regulator system A (CsrA), the upstream regulator of RovM, dramatically down-regulates urease activity possibly by its binding to the Shine-Dalgarno (SD) sequence of the mRNA encoding the urease. In conclusion, this study demonstrates that urease activity is strictly controlled by nutrient conditions and is down-regulated by the CsrA-RovM pathway.
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Affiliation(s)
- Qingyun Dai
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China
| | - Lei Xu
- College of Life Sciences, Northwest A&F University, Yangling, China
- Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Lu Xiao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China
| | - Kaixiang Zhu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China
| | - Yunhong Song
- College of Life Sciences, Northwest A&F University, Yangling, China
| | - Changfu Li
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China
| | - Lingfang Zhu
- College of Life Sciences, Northwest A&F University, Yangling, China
| | - Xihui Shen
- College of Life Sciences, Northwest A&F University, Yangling, China
- Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Yao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China
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118
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Su T, Si M, Zhao Y, Liu Y, Yao S, Che C, Chen C. A thioredoxin-dependent peroxiredoxin Q from Corynebacterium glutamicum plays an important role in defense against oxidative stress. PLoS One 2018; 13:e0192674. [PMID: 29438446 PMCID: PMC5811025 DOI: 10.1371/journal.pone.0192674] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/29/2018] [Indexed: 02/07/2023] Open
Abstract
Peroxiredoxin Q (PrxQ) that belonged to the cysteine-based peroxidases has long been identified in numerous bacteria, but the information on the physiological and biochemical functions of PrxQ remain largely lacking in Corynebacterium glutamicum. To better systematically understand PrxQ, we reported that PrxQ from model and important industrial organism C. glutamicum, encoded by the gene ncgl2403 annotated as a putative PrxQ, played important roles in adverse stress resistance. The lack of C. glutamicum prxQ gene resulted in enhanced cell sensitivity, increased ROS accumulation, and elevated protein carbonylation levels under adverse stress conditions. Accordingly, PrxQ-mediated resistance to adverse stresses mainly relied on the degradation of ROS. The physiological roles of PrxQ in resistance to adverse stresses were corroborated by its induced expression under adverse stresses, regulated directly by the stress-responsive ECF-sigma factor SigH. Through catalytical kinetic activity, heterodimer formation, and bacterial two-hybrid analysis, we proved that C. glutamicum PrxQ catalytically eliminated peroxides by exclusively receiving electrons from thioredoxin (Trx)/thioredoxin reductase (TrxR) system and had a broad range of oxidizing substrates, but a better efficiency for peroxynitrite and cumene hydroperoxide (CHP). Site-directed mutagenesis confirmed that the conserved Cys49 and Cys54 are the peroxide oxidation site and the resolving Cys residue, respectively. It was also discovered that C. glutamicum PrxQ mainly existed in monomer whether under its native state or functional state. Based on these results, a catalytic model of PrxQ is being proposed. Moreover, our result that C. glutamicum PrxQ can prevent the damaging effects of adverse stresses by acting as thioredoxin-dependent monomeric peroxidase could be further applied to improve the survival ability and robustness of the important bacterium during fermentation process.
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Affiliation(s)
- Tao Su
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Meiru Si
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Yunfeng Zhao
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Yan Liu
- School of Geography And Tourism, Qufu Normal University, Rizhao, Shandong, China
| | - Shumin Yao
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Chengchuan Che
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, China
| | - Can Chen
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, Henan, China
- * E-mail:
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119
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Yang Z, Zhou X, Ma Y, Zhou M, Waldor MK, Zhang Y, Wang Q. Serine/threonine kinase PpkA coordinates the interplay between T6SS2 activation and quorum sensing in the marine pathogen Vibrio alginolyticus. Environ Microbiol 2018; 20:903-919. [PMID: 29314504 DOI: 10.1111/1462-2920.14039] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/31/2017] [Accepted: 12/31/2017] [Indexed: 11/30/2022]
Abstract
Type VI secretion systems (T6SS) are multiprotein secretion machines that can mediate killing of bacterial cells and thereby modify the composition of bacterial communities. The mechanisms that control the production of and secretion of these killing machines are incompletely understood, although quorum sensing (QS) and the PpkA kinase modulate T6SS activity in some organisms. Here we investigated control the T6S in the marine organism Vibrio alginolyticus EPGS, which encodes two T6SS systems (T6SS1 and T6SS2). We found that the organism principally relies on T6SS2 for interbacterial competition. We further carried out a phosphoproteomic screen to identify substrates of the T6SS2-linked PpkA2 kinase. Substrates of PpkA2 encoded within the T6SS2 cluster as well proteins that are apparently not linked to T6SS-related processes were identified. Similar to other organisms, PpkA2 autophosphorylation was critical for T6SS2 function. Notably, phosphorylation of a polypeptide encoded outside of the T6SS2 cluster, VtsR, was critical for T6SS2 expression and function because it augments the expression of luxR, a key regulator of QS that also promotes T6SS2 gene expression. Thus, PpkA2 controls a phosphorylation cascade that mediates a positive regulatory loop entwining T6SS and QS, thereby coordinating these pathways to enhance the competitive fitness of V. alginolyticus.
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Affiliation(s)
- Zhen Yang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xiaohui Zhou
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT 06269, USA.,Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
| | - Yue Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.,Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| | - Mian Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.,Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| | - Matthew K Waldor
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.,Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, 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, Shanghai, China
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120
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Wu CF, Smith DA, Lai EM, Chang JH. The Agrobacterium Type VI Secretion System: A Contractile Nanomachine for Interbacterial Competition. Curr Top Microbiol Immunol 2018; 418:215-231. [PMID: 29992360 DOI: 10.1007/82_2018_99] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The bacterial type VI secretion system (T6SS) is a contractile nanomachine dedicated to delivering molecules out of bacterial cells. T6SS-encoding loci are in the genome sequences of many Gram-negative bacteria, and T6SS has been implicated in a plethora of roles. In the majority of cases, the T6SSs deliver effector proteins in a contact-dependent manner to antagonize other bacteria. Current models suggest that the effectors are deployed to influence social interactions in microbial communities. In this chapter, we describe the structure, function, and regulation of the T6SS and its effectors. We provide focus on the T6SS of Agrobacterium tumefaciens, the causative agent of crown gall disease, and relate the role of the T6SS to the ecology of A. tumefaciens.
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Affiliation(s)
- Chih-Feng Wu
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - Delaney A Smith
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA.
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121
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Bernal P, Llamas MA, Filloux A. Type VI secretion systems in plant-associated bacteria. Environ Microbiol 2017; 20:1-15. [PMID: 29027348 PMCID: PMC5813230 DOI: 10.1111/1462-2920.13956] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 10/02/2017] [Accepted: 10/05/2017] [Indexed: 11/28/2022]
Abstract
The type VI secretion system (T6SS) is a bacterial nanomachine used to inject effectors into prokaryotic or eukaryotic cells and is thus involved in both host manipulation and interbacterial competition. The T6SS is widespread among Gram‐negative bacteria, mostly within the Proteobacterium Phylum. This secretion system is commonly found in commensal and pathogenic plant‐associated bacteria. Phylogenetic analysis of phytobacterial T6SS clusters shows that they are distributed in the five main clades previously described (group 1–5). The even distribution of the system among commensal and pathogenic phytobacteria suggests that the T6SS provides fitness and colonization advantages in planta and that the role of the T6SS is not restricted to virulence. This manuscript reviews the phylogeny and biological roles of the T6SS in plant‐associated bacteria, highlighting a remarkable diversity both in terms of mechanism and function.
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Affiliation(s)
- Patricia Bernal
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Flowers Building, 1st floor South Kensington Campus, Imperial College London, London SW7 2AZ, UK
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - Alain Filloux
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Flowers Building, 1st floor South Kensington Campus, Imperial College London, London SW7 2AZ, UK
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122
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Li J, Qian S, Xiong L, Zhu C, Shu M, Wang J, Jiao Y, He H, Zhang F, Linhardt RJ, Zhong W. Comparative Genomics Reveals Specific Genetic Architectures in Nicotine Metabolism of Pseudomonas sp. JY-Q. Front Microbiol 2017; 8:2085. [PMID: 29163390 PMCID: PMC5674928 DOI: 10.3389/fmicb.2017.02085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/11/2017] [Indexed: 12/21/2022] Open
Abstract
Microbial degradation of nicotine is an important process to control nicotine residues in the aqueous environment. In this study, a high active nicotine degradation strain named Pseudomonas sp. JY-Q was isolated from tobacco waste extract (TWE). This strain could completely degrade 5.0 g l−1 nicotine in 24 h under optimal culture conditions, and it showed some tolerance even at higher concentrations (10.0 g l−1) of nicotine. The complete genome of JY-Q was sequenced to understand the mechanism by which JY-Q could degrade nicotine and tolerate such high nicotine concentrations. Comparative genomic analysis indicated that JY-Q degrades nicotine through putative novel mechanisms. Two candidate gene cluster duplications located separately at distant loci were predicted to be responsible for nicotine degradation. These two nicotine (Nic) degradation-related loci (AA098_21325—AA098_21340, AA098_03885—AA098_03900) exhibit nearly completely consistent gene organization and component synteny. The nicotinic acid (NA) degradation gene cluster (AA098_17770–AA098_17790) and Nic-like clusters were both predicted to be flanked by mobile genetic elements (MGE). Furthermore, we analyzed the regions of genomic plasticity (RGP) in the JY-Q strain and found a dynamic genome carrying a type VI secretion system (T6SS) that promotes nicotine metabolism and tolerance based on transcriptomics and used in silico methods to identify the T6SS effector protein. Thus, a novel nicotine degradation mechanism was elucidated for Pseudomonas sp. JY-Q, suggesting its potential application in the bioremediation of nicotine-contaminated environments, such as TWEs.
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Affiliation(s)
- Jun Li
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Shulan Qian
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Lie Xiong
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Chengyun Zhu
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Ming Shu
- Technology Center, China Tobacco Zhejiang Industrial Co., Ltd., Hangzhou, China
| | - Jie Wang
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Yang Jiao
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Houlong He
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Fuming Zhang
- Departments of Chemical and Biological Engineering, Biological Science, Chemistry and Chemical Biology and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Robert J Linhardt
- Departments of Chemical and Biological Engineering, Biological Science, Chemistry and Chemical Biology and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Weihong Zhong
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
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123
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Saak CC, Zepeda-Rivera MA, Gibbs KA. A single point mutation in a TssB/VipA homolog disrupts sheath formation in the type VI secretion system of Proteus mirabilis. PLoS One 2017; 12:e0184797. [PMID: 28949977 PMCID: PMC5614524 DOI: 10.1371/journal.pone.0184797] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 08/31/2017] [Indexed: 01/21/2023] Open
Abstract
The type VI secretion (T6S) system is a molecular device for the delivery of proteins from one cell into another. T6S function depends on the contractile sheath comprised of TssB/VipA and TssC/VipB proteins. We previously reported on a mutant variant of TssB that disrupts T6S-dependent export of the self-identity protein, IdsD, in the bacterium Proteus mirabilis. Here we determined the mechanism underlying that initial observation. We show that T6S-dependent export of multiple self-recognition proteins is abrogated in this mutant strain. We have mapped the mutation, which is a single amino acid change, to a region predicted to be involved in the formation of the TssB-TssC sheath. We have demonstrated that this mutation does indeed inhibit sheath formation, thereby explaining the global disruption of T6S activity. We propose that this mutation could be utilized as an important tool for studying functions and behaviors associated with T6S systems.
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Affiliation(s)
- Christina C. Saak
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Martha A. Zepeda-Rivera
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Karine A. Gibbs
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail:
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124
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Gallique M, Bouteiller M, Merieau A. The Type VI Secretion System: A Dynamic System for Bacterial Communication? Front Microbiol 2017; 8:1454. [PMID: 28804481 PMCID: PMC5532429 DOI: 10.3389/fmicb.2017.01454] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/18/2017] [Indexed: 11/13/2022] Open
Abstract
Numerous studies in Gram-negative bacteria have focused on the Type VISecretion Systems (T6SSs), Quorum Sensing (QS), and social behavior, such as in biofilms. These interconnected mechanisms are important for bacterial survival; T6SSs allow bacteria to battle other cells, QS is devoted to the perception of bacterial cell density, and biofilm formation is essentially controlled by QS. Here, we review data concerning T6SS dynamics and T6SS–QS cross-talk that suggest the existence of inter-bacterial communication via T6SSs.
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Affiliation(s)
- Mathias Gallique
- Laboratoire de Microbiologie Signaux et Microenvironnement EA 4312, l'Institut Universitaire de Technologie d'Evreux (IUT), Université de Rouen, Normandy UniversityEvreux, France
| | - Mathilde Bouteiller
- Laboratoire de Microbiologie Signaux et Microenvironnement EA 4312, l'Institut Universitaire de Technologie d'Evreux (IUT), Université de Rouen, Normandy UniversityEvreux, France
| | - Annabelle Merieau
- Laboratoire de Microbiologie Signaux et Microenvironnement EA 4312, l'Institut Universitaire de Technologie d'Evreux (IUT), Université de Rouen, Normandy UniversityEvreux, France
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125
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Lien YW, Lai EM. Type VI Secretion Effectors: Methodologies and Biology. Front Cell Infect Microbiol 2017; 7:254. [PMID: 28664151 PMCID: PMC5471719 DOI: 10.3389/fcimb.2017.00254] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/31/2017] [Indexed: 12/26/2022] Open
Abstract
The type VI secretion system (T6SS) is a nanomachine deployed by many Gram-negative bacteria as a weapon against eukaryotic hosts or prokaryotic competitors. It assembles into a bacteriophage tail-like structure that can transport effector proteins into the environment or target cells for competitive survival or pathogenesis. T6SS effectors have been identified by a variety of approaches, including knowledge/hypothesis-dependent and discovery-driven approaches. Here, we review and discuss the methods that have been used to identify T6SS effectors and the biological and biochemical functions of known effectors. On the basis of the nature and transport mechanisms of T6SS effectors, we further propose potential strategies that may be applicable to identify new T6SS effectors.
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Affiliation(s)
- Yun-Wei Lien
- Institute of Plant and Microbial Biology, Academia SinicaTaipei, Taiwan.,Department of Plant Pathology and Microbiology, National Taiwan UniversityTaipei, Taiwan
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia SinicaTaipei, Taiwan.,Department of Plant Pathology and Microbiology, National Taiwan UniversityTaipei, Taiwan
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126
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A starvation-induced regulator, RovM, acts as a switch for planktonic/biofilm state transition in Yersinia pseudotuberculosis. Sci Rep 2017; 7:639. [PMID: 28377623 PMCID: PMC5428675 DOI: 10.1038/s41598-017-00534-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/28/2017] [Indexed: 01/31/2023] Open
Abstract
The transition between the planktonic state and the biofilm-associated state is a key developmental decision for pathogenic bacteria. Biofilm formation by Yersinia pestis is regulated by hmsHFRS genes (β-1, 6-N-acetyl-D-glucosamine synthesis operon) in its flea vector and in vitro. However, the mechanism of biofilm formation in Yersinia pseudotuberculosis remains elusive. In this study, we demonstrate that the LysR-type regulator RovM inversely regulates biofilm formation and motility in Y. pseudotuberculosis by acting as a transcriptional regulator of these two functions. RovM is strongly induced during growth in minimal media but strongly repressed in complex media. On one hand, RovM enhances bacterial motility by activating the expression of FlhDC, the master regulator of flagellar genes, via the recognition of an operator upstream of the flhDC promoter. On the other hand, RovM represses β-GlcNAc production under nutrition-limited conditions, negatively regulating hmsHFRS expression by directly binding to the -35 element of its promoter. Compared to wild-type bacteria, the rovM mutant established denser biofilms and caused more extensive mortality in mice and silkworm larvae. These results indicate that RovM acts as a molecular switch to coordinate the expression of genes involved in biofilm formation and motility in response to the availability of nutrients.
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127
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A Pseudomonas T6SS effector recruits PQS-containing outer membrane vesicles for iron acquisition. Nat Commun 2017; 8:14888. [PMID: 28348410 PMCID: PMC5379069 DOI: 10.1038/ncomms14888] [Citation(s) in RCA: 202] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 02/09/2017] [Indexed: 01/20/2023] Open
Abstract
Iron sequestration by host proteins contributes to the defence against bacterial pathogens, which need iron for their metabolism and virulence. A Pseudomonas aeruginosa mutant lacking all three known iron acquisition systems retains the ability to grow in media containing iron chelators, suggesting the presence of additional pathways involved in iron uptake. Here we screen P. aeruginosa mutants defective in growth in iron-depleted media and find that gene PA2374, proximal to the type VI secretion system H3 (H3-T6SS), functions synergistically with known iron acquisition systems. PA2374 (which we have renamed TseF) appears to be secreted by H3-T6SS and is incorporated into outer membrane vesicles (OMVs) by directly interacting with the iron-binding Pseudomonas quinolone signal (PQS), a cell–cell signalling compound. TseF facilitates the delivery of OMV-associated iron to bacterial cells by engaging the Fe(III)-pyochelin receptor FptA and the porin OprF. Our results reveal links between type VI secretion, cell–cell signalling and classic siderophore receptors for iron acquisition in P. aeruginosa. Pathogens require iron for their metabolism and virulence. Here the authors identify an iron acquisition system in Pseudomonas aeruginosa involving a protein secreted by a type VI secretion system, the PQS signalling compound and siderophore receptors.
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128
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Wang T, Chen K, Gao F, Kang Y, Chaudhry MT, Wang Z, Wang Y, Shen X. ZntR positively regulates T6SS4 expression in Yersinia pseudotuberculosis. J Microbiol 2017; 55:448-456. [PMID: 28281200 DOI: 10.1007/s12275-017-6540-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/26/2017] [Accepted: 02/03/2017] [Indexed: 12/21/2022]
Abstract
The type VI secretion system (T6SS) is a widespread and versatile protein secretion system found in most Gram-negative bacteria. Studies of T6SS have mainly focused on its role in virulence toward host cells and inter-bacterial interactions, but studies have also shown that T6SS4 in Yersinia pseudotuberculosis participates in the acquisition of zinc ions to alleviate the accumulation of hydroxyl radicals induced by multiple stressors. Here, by comparing the gene expression patterns of wild-type and zntR mutant Y. pseudotuberculosis cells using RNA-seq analysis, T6SS4 and 17 other biological processes were found to be regulated by ZntR. T6SS4 was positively regulated by ZntR in Y. pseudotuberculosis, and further investigation demonstrated that ZntR regulates T6SS4 by directly binding to its promoter region. T6SS4 expression is regulated by zinc via ZntR, which maintains intracellular zinc homeostasis and controls the concentration of reactive oxygen species to prevent bacterial death under oxidative stress. This study provides new insights into the regulation of T6SS4 by a zinc-dependent transcriptional regulator, and it provides a foundation for further investigation of the mechanism of zinc transport by T6SS.
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Affiliation(s)
- Tietao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Keqi Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Fen Gao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Yiwen Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Muhammad Tausif Chaudhry
- Environmental Analytical Laboratory, National Physical and Standards Laboratory, PCSIR, Islamabad, Pakistan
| | - Zhuo Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Yao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, P. R. China.
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, P. R. China.
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129
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Manganese scavenging and oxidative stress response mediated by type VI secretion system in Burkholderia thailandensis. Proc Natl Acad Sci U S A 2017; 114:E2233-E2242. [PMID: 28242693 DOI: 10.1073/pnas.1614902114] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Type VI secretion system (T6SS) is a versatile protein export machinery widely distributed in Gram-negative bacteria. Known to translocate protein substrates to eukaryotic and prokaryotic target cells to cause cellular damage, the T6SS has been primarily recognized as a contact-dependent bacterial weapon for microbe-host and microbial interspecies competition. Here we report contact-independent functions of the T6SS for metal acquisition, bacteria competition, and resistance to oxidative stress. We demonstrate that the T6SS-4 in Burkholderia thailandensis is critical for survival under oxidative stress and is regulated by OxyR, a conserved oxidative stress regulator. The T6SS-4 is important for intracellular accumulation of manganese (Mn2+) under oxidative stress. Next, we identified a T6SS-4-dependent Mn2+-binding effector TseM, and its interacting partner MnoT, a Mn2+-specific TonB-dependent outer membrane transporter. Similar to the T6SS-4 genes, expression of mnoT is regulated by OxyR and is induced under oxidative stress and low Mn2+ conditions. Both TseM and MnoT are required for efficient uptake of Mn2+ across the outer membrane under Mn2+-limited and -oxidative stress conditions. The TseM-MnoT-mediated active Mn2+ transport system is also involved in contact-independent bacteria-bacteria competition and bacterial virulence. This finding provides a perspective for understanding the mechanisms of metal ion uptake and the roles of T6SS in bacteria-bacteria competition.
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130
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Si M, Wang T, Pan J, Lin J, Chen C, Wei Y, Lu Z, Wei G, Shen X. Graded Response of the Multifunctional 2-Cysteine Peroxiredoxin, CgPrx, to Increasing Levels of Hydrogen Peroxide in Corynebacterium glutamicum. Antioxid Redox Signal 2017; 26:1-14. [PMID: 27324811 DOI: 10.1089/ars.2016.6650] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS Eukaryotic typical 2-cysteine (Cys) peroxiredoxins (Prxs) are multifunctional proteins subjected to complex regulation and play important roles in oxidative stress resistance, hydrogen peroxide (H2O2) signaling modulation, aging, and cancer, but the information on the biochemical functions and regulation mechanisms of prokaryotic atypical 2-Cys Prxs is largely lacking. RESULTS In this study, we show that at low peroxide concentrations, the atypical 2-Cys Prx in Corynebacterium glutamicum (CgPrx) mainly exists as monomers and displays thioredoxin (Trx)-dependent peroxidase activity. Moderate oxidative stress causes reversible S-mycothiolation of the H2O2-sensing Cys63 residue, which keeps CgPrx exclusively in dimer form with neither peroxidase nor chaperone activity. Then, the increased levels of H2O2 could act as a messenger to oxidize the redox-sensitive regulator hydrogen peroxide-inducible gene activator, leading to activation of expression of the more efficient mycothiol peroxidase and catalase to eliminate excessive peroxide. If oxidative stress is too severe, the H2O2-sensing Cys63 becomes hyperoxidized to sulfonic acid, which irreversibly inactivates the peroxidase activity, and most of CgPrx will be converted to multimeric chaperones for salvage of damaged proteins. INNOVATION We demonstrate for the first time that atypical 2-Cys CgPrx acts as both a Trx-dependent peroxidase and a molecular chaperone and plays a regulatory role in modulating the peroxide-mediated signaling cascades. CONCLUSION These results reveal that CgPrx functions as a multifunctional protein crucial for adapting appropriate responses to different levels of oxidative challenge in C. glutamicum. Antioxid. Redox Signal. 26, 1-14.
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Affiliation(s)
- Meiru Si
- 1 State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University , Yangling, China .,2 College of Plant Protection, Northwest A&F University , Yangling, China
| | - Tietao Wang
- 1 State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University , Yangling, China
| | - Junfeng Pan
- 1 State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University , Yangling, China
| | - Jinshui Lin
- 1 State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University , Yangling, China
| | - Can Chen
- 1 State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University , Yangling, China
| | - Yahong Wei
- 1 State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University , Yangling, China
| | - Zhiqiang Lu
- 2 College of Plant Protection, Northwest A&F University , Yangling, China
| | - Gehong Wei
- 1 State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University , Yangling, China
| | - Xihui Shen
- 1 State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University , Yangling, China
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Abstract
Transition metals are required trace elements for all forms of life. Due to their unique inorganic and redox properties, transition metals serve as cofactors for enzymes and other proteins. In bacterial pathogenesis, the vertebrate host represents a rich source of nutrient metals, and bacteria have evolved diverse metal acquisition strategies. Host metal homeostasis changes dramatically in response to bacterial infections, including production of metal sequestering proteins and the bombardment of bacteria with toxic levels of metals. In response, bacteria have evolved systems to subvert metal sequestration and toxicity. The coevolution of hosts and their bacterial pathogens in the battle for metals has uncovered emerging paradigms in social microbiology, rapid evolution, host specificity, and metal homeostasis across domains. This review focuses on recent advances and open questions in our understanding of the complex role of transition metals at the host-pathogen interface.
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Affiliation(s)
- Lauren D Palmer
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37212;
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37212;
- Tennessee Valley Healthcare System, US Department of Veterans Affairs, Nashville, Tennessee 37212
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132
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Chen C, Pan J, Yang X, Xiao H, Zhang Y, Si M, Shen X, Wang Y. Global transcriptomic analysis of the response of Corynebacterium glutamicum to ferulic acid. Arch Microbiol 2016; 199:325-334. [DOI: 10.1007/s00203-016-1306-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 08/24/2016] [Accepted: 10/08/2016] [Indexed: 10/20/2022]
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133
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Global Transcriptomic Analysis of the Response of Corynebacterium glutamicum to Vanillin. PLoS One 2016; 11:e0164955. [PMID: 27760214 PMCID: PMC5070772 DOI: 10.1371/journal.pone.0164955] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 10/04/2016] [Indexed: 12/01/2022] Open
Abstract
Lignocellulosic biomass is an abundant and renewable resource for biofuels and bio-based chemicals. Vanillin is one of the major phenolic inhibitors in biomass production using lignocellulose. To assess the response of Corynebacterium glutamicum to vanillin stress, we performed a global transcriptional response analysis. The transcriptional data showed that the vanillin stress not only affected the genes involved in degradation of vanillin, but also differentially regulated several genes related to the stress response, ribosome/translation, protein secretion, and the cell envelope. Moreover, deletion of the sigH or msrA gene in C. glutamicum resulted in a decrease in cell viability under vanillin stress. These insights will promote further engineering of model industrial strains, with enhanced tolerance or degradation ability to vanillin to enable suitable production of biofuels and bio-based chemicals from lignocellulosic biomass.
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134
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Vicente CSL, Nascimento FX, Barbosa P, Ke HM, Tsai IJ, Hirao T, Cock PJA, Kikuchi T, Hasegawa K, Mota M. Evidence for an Opportunistic and Endophytic Lifestyle of the Bursaphelenchus xylophilus-Associated Bacteria Serratia marcescens PWN146 Isolated from Wilting Pinus pinaster. MICROBIAL ECOLOGY 2016; 72:669-681. [PMID: 27461253 DOI: 10.1007/s00248-016-0820-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 07/08/2016] [Indexed: 06/06/2023]
Abstract
Pine wilt disease (PWD) results from the interaction of three elements: the pathogenic nematode, Bursaphelenchus xylophilus; the insect-vector, Monochamus sp.; and the host tree, mostly Pinus species. Bacteria isolated from B. xylophilus may be a fourth element in this complex disease. However, the precise role of bacteria in this interaction is unclear as both plant-beneficial and as plant-pathogenic bacteria may be associated with PWD. Using whole genome sequencing and phenotypic characterization, we were able to investigate in more detail the genetic repertoire of Serratia marcescens PWN146, a bacterium associated with B. xylophilus. We show clear evidence that S. marcescens PWN146 is able to withstand and colonize the plant environment, without having any deleterious effects towards a susceptible host (Pinus thunbergii), B. xylophilus nor to the nematode model C. elegans. This bacterium is able to tolerate growth in presence of xenobiotic/organic compounds, and use phenylacetic acid as carbon source. Furthermore, we present a detailed list of S. marcescens PWN146 potentials to interfere with plant metabolism via hormonal pathways and/or nutritional acquisition, and to be competitive against other bacteria and/or fungi in terms of resource acquisition or production of antimicrobial compounds. Further investigation is required to understand the role of bacteria in PWD. We have now reinforced the theory that B. xylophilus-associated bacteria may have a plant origin.
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Affiliation(s)
- Cláudia S L Vicente
- NemaLab/ICAAM-Institute of Mediterranean Agricultural and Environmental Sciences, Biology Department, University of Évora, Évora, Portugal.
- Department of Environmental Biology, Chubu University, Kasugai, Japan.
| | - Francisco X Nascimento
- NemaLab/ICAAM-Institute of Mediterranean Agricultural and Environmental Sciences, Biology Department, University of Évora, Évora, Portugal
- Departamento de Microbiologia, Laboratório de Microbiologia do Solo, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Pedro Barbosa
- NemaLab/ICAAM-Institute of Mediterranean Agricultural and Environmental Sciences, Biology Department, University of Évora, Évora, Portugal
| | - Huei-Mien Ke
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung, Taiwan
| | - Isheng J Tsai
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Tomonori Hirao
- Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Ibaraki, Japan
| | - Peter J A Cock
- Information and Computer Sciences group, The James Hutton Institute, Invergowrie, DD2 5DA, Dundee, UK
| | - Taisei Kikuchi
- Division of Parasitology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Koichi Hasegawa
- Department of Environmental Biology, Chubu University, Kasugai, Japan
| | - Manuel Mota
- NemaLab/ICAAM-Institute of Mediterranean Agricultural and Environmental Sciences, Biology Department, University of Évora, Évora, Portugal
- Departamento de Ciências da Vida, Universidade Lusófona de Humanidades e Tecnologias, Lisbon, Portugal
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135
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Overexpression of Mycothiol Disulfide Reductase Enhances Corynebacterium glutamicum Robustness by Modulating Cellular Redox Homeostasis and Antioxidant Proteins under Oxidative Stress. Sci Rep 2016; 6:29491. [PMID: 27383057 PMCID: PMC4935862 DOI: 10.1038/srep29491] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 06/17/2016] [Indexed: 01/30/2023] Open
Abstract
Mycothiol (MSH) is the dominant low-molecular-weight thiol (LMWT) unique to high-(G+C)-content Gram-positive Actinobacteria, such as Corynebacterium glutamicum, and is oxidised into its disulfide form mycothiol disulfide (MSSM) under oxidative conditions. Mycothiol disulfide reductase (Mtr), an NADPH-dependent enzyme, reduces MSSM to MSH, thus maintaining intracellular redox homeostasis. In this study, a recombinant plasmid was constructed to overexpress Mtr in C. glutamicum using the expression vector pXMJ19-His6. Mtr-overexpressing C. glutamicum cells showed increased tolerance to ROS induced by oxidants, bactericidal antibiotics, alkylating agents, and heavy metals. The physiological roles of Mtr in resistance to oxidative stresses were corroborated by decreased ROS levels, reduced carbonylation damage, decreased loss of reduced protein thiols, and a massive increase in the levels of reversible protein thiols in Mtr-overexpressing cells exposed to stressful conditions. Moreover, overexpression of Mtr caused a marked increase in the ratio of reduced to oxidised mycothiol (MSH:MSSM), and significantly enhanced the activities of a variety of antioxidant enzymes, including mycothiol peroxidase (MPx), mycoredoxin 1 (Mrx1), thioredoxin 1 (Trx1), and methionine sulfoxide reductase A (MsrA). Taken together, these results indicate that the Mtr protein functions in C. glutamicum by protecting cells against oxidative stress.
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136
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Basler M. Type VI secretion system: secretion by a contractile nanomachine. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2015.0021. [PMID: 26370934 PMCID: PMC4632598 DOI: 10.1098/rstb.2015.0021] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The type VI secretion systems (T6SS) are present in about a quarter of all Gram-negative bacteria. Several key components of T6SS are evolutionarily related to components of contractile nanomachines such as phages and R-type pyocins. The T6SS assembly is initiated by formation of a membrane complex that binds a phage-like baseplate with a sharp spike, and this is followed by polymerization of a long rigid inner tube and an outer contractile sheath. Effectors are preloaded onto the spike or into the tube during the assembly by various mechanisms. Contraction of the sheath releases an unprecedented amount of energy, which is used to thrust the spike and tube with the associated effectors out of the effector cell and across membranes of both bacterial and eukaryotic target cells. Subunits of the contracted sheath are recycled by T6SS-specific unfoldase to allow for a new round of assembly. Live-cell imaging has shown that the assembly is highly dynamic and its subcellular localization is in certain bacteria regulated with a remarkable precision. Through the action of effectors, T6SS has mainly been shown to contribute to pathogenicity and competition between bacteria. This review summarizes the knowledge that has contributed to our current understanding of T6SS mode of action.
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Affiliation(s)
- Marek Basler
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
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137
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Mycothiol peroxidase MPx protects Corynebacterium glutamicum against acid stress by scavenging ROS. Biotechnol Lett 2016; 38:1221-8. [DOI: 10.1007/s10529-016-2099-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/31/2016] [Indexed: 10/22/2022]
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138
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Chen S, Thompson KM, Francis MS. Environmental Regulation of Yersinia Pathophysiology. Front Cell Infect Microbiol 2016; 6:25. [PMID: 26973818 PMCID: PMC4773443 DOI: 10.3389/fcimb.2016.00025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/15/2016] [Indexed: 12/26/2022] Open
Abstract
Hallmarks of Yersinia pathogenesis include the ability to form biofilms on surfaces, the ability to establish close contact with eukaryotic target cells and the ability to hijack eukaryotic cell signaling and take over control of strategic cellular processes. Many of these virulence traits are already well-described. However, of equal importance is knowledge of both confined and global regulatory networks that collaborate together to dictate spatial and temporal control of virulence gene expression. This review has the purpose to incorporate historical observations with new discoveries to provide molecular insight into how some of these regulatory mechanisms respond rapidly to environmental flux to govern tight control of virulence gene expression by pathogenic Yersinia.
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Affiliation(s)
- Shiyun Chen
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences Wuhan, China
| | - Karl M Thompson
- Department of Microbiology, College of Medicine, Howard University Washington, DC, USA
| | - Matthew S Francis
- Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden; Department of Molecular Biology, Umeå UniversityUmeå, Sweden
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139
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Zinc acquisition via ZnuABC in Yersinia pseudotuberculosis facilitates resistance to oxidative stress. ANN MICROBIOL 2016. [DOI: 10.1007/s13213-016-1205-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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140
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Liu Y, Yang X, Yin Y, Lin J, Chen C, Pan J, Si M, Shen X. Mycothiol protects Corynebacterium glutamicum against acid stress via maintaining intracellular pH homeostasis, scavenging ROS, and S-mycothiolating MetE. J GEN APPL MICROBIOL 2016; 62:144-53. [DOI: 10.2323/jgam.2016.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Yingbao Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
- College of Life Science, Yangtze University
| | - Xiaobing Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
| | - Yajie Yin
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences
| | - Jinshui Lin
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
| | - Can Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
| | - Junfeng Pan
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
| | - Meiru Si
- College of Life Sciences, Qufu Normal University
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
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141
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Hachani A, Wood TE, Filloux A. Type VI secretion and anti-host effectors. Curr Opin Microbiol 2015; 29:81-93. [PMID: 26722980 DOI: 10.1016/j.mib.2015.11.006] [Citation(s) in RCA: 189] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/25/2015] [Accepted: 11/26/2015] [Indexed: 11/30/2022]
Abstract
Secretion systems play a central role in infectious diseases by enabling pathogenic bacteria to deliver virulence factors into target cells. The type VI secretion system (T6SS) mediates bacterial antagonism in various environments including eukaryotic niches, such as the gut. This molecular machine injects lethal toxins directly in target bacterial cells. It provides an advantage to pathogens encountering the commensal flora of the host and indirectly contributes to colonization and persistence. Yet, the T6SS is not employed for the sole purpose of bacterial killing and several T6SS effectors are dedicated to the subversion of eukaryotic cells. As described for type III and type IV secretion systems, these effectors impede host cell functions and promote immune evasion, thereby enabling successful infection.
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Affiliation(s)
- Abderrahman Hachani
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, SW72AZ London, United Kingdom; Department of Pathogen Molecular Biology, Faculty of Infection and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom; Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Victoria 3000, Australia
| | - Thomas E Wood
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, SW72AZ London, United Kingdom
| | - Alain Filloux
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, SW72AZ London, United Kingdom.
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142
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Tang L, Liang X, Moore R, Dong TG. Commentary: The icmF3 Locus is Involved in Multiple Adaptation- and Virulence-related Characteristics in Pseudomonas aeruginosa PAO1. Front Cell Infect Microbiol 2015; 5:83. [PMID: 26636045 PMCID: PMC4649053 DOI: 10.3389/fcimb.2015.00083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 11/03/2015] [Indexed: 11/25/2022] Open
Affiliation(s)
- Le Tang
- Ecosystem and Public Health, University of Calgary Calgary, AB, Canada
| | - Xiaoye Liang
- Ecosystem and Public Health, University of Calgary Calgary, AB, Canada
| | - Richard Moore
- Ecosystem and Public Health, University of Calgary Calgary, AB, Canada
| | - Tao G Dong
- Ecosystem and Public Health, University of Calgary Calgary, AB, Canada
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143
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Lin J, Cheng J, Chen K, Guo C, Zhang W, Yang X, Ding W, Ma L, Wang Y, Shen X. The icmF3 locus is involved in multiple adaptation- and virulence-related characteristics in Pseudomonas aeruginosa PAO1. Front Cell Infect Microbiol 2015; 5:70. [PMID: 26484316 PMCID: PMC4589678 DOI: 10.3389/fcimb.2015.00070] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 09/18/2015] [Indexed: 11/24/2022] Open
Abstract
The type VI secretion system (T6SS) is widely distributed in Gram-negative bacteria. Three separate T6SSs called H1-, H2-, and H3-T6SS have been discovered in Pseudomonas aeruginosa PAO1. Recent studies suggest that, in contrast to the H1-T6SS that targets prokaryotic cells, H2- and H3-T6SS are involved in interactions with both prokaryotic and eukaryotic cells. However, the detailed functions of T6SS components are still uncharacterized. The intracellular multiplication factor (IcmF) protein is conserved in type VI secretion systems (T6SS) of all different bacterial pathogens. Bioinformatic analysis revealed that IcmF3 in P. aeruginosa PAO1 is different from other IcmF homologs and may represent a new branch of these proteins with distinct functions. Herein, we have investigated the function of IcmF3 in this strain. We have shown that deletion of the icmF3 gene in P. aeruginosa PAO1 is associated with pleiotropic phenotypes. The icmF3 mutant has variant colony morphology and an hypergrowth phenotype in iron-limiting medium. Surprisingly, this mutant is also defective for the production of pyoverdine, as well as defects in swimming motility and virulence in a C. elegans worm model. The icmF3 mutant exhibits higher conjugation frequency than the wild type and increased biofilm formation on abiotic surfaces. Additionally, expression of two phenazine biosynthetic loci is increased in the icmF3 mutant, leading to the overproduction of pyocyanin. Finally, the mutant exhibits decreased susceptibility to aminoglycosides such as tobramycin and gentamicin. And the detected phenotypes can be restored completely or partially by trans complementation of wild type icmF3 gene. The pleiotropic effects observed upon icmF3 deletion demonstrate that icmF3 plays critical roles in both pathogenesis and environmental adaptation in P. aeruginosa PAO1.
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Affiliation(s)
- Jinshui Lin
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China
| | - Juanli Cheng
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China ; Life Sciences Department, Yuncheng University Yuncheng, China
| | - Keqi Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China
| | - Chenghao Guo
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China
| | - Weipeng Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China
| | - Xu Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China
| | - Wei Ding
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China
| | - Li Ma
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China
| | - Yao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University Yangling, China
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