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Jeong GJ, Khan F, Tabassum N, Kim YM. Cellular and physiological roles of sigma factors in Vibrio spp.: A comprehensive review. Int J Biol Macromol 2024; 254:127833. [PMID: 37918595 DOI: 10.1016/j.ijbiomac.2023.127833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 11/04/2023]
Abstract
Vibrio species are motile gram-negative bacteria commonly found in aquatic environments. Vibrio species include pathogenic as well as non-pathogenic strains. Pathogenic Vibrio species have been reported in invertebrates and humans, whereas non-pathogenic strains are involved in symbiotic relationships with their eukaryotic hosts. These bacteria are also able to adapt to fluctuations in temperature, salinity, and pH, in addition to oxidative stress, and osmotic pressure in aquatic ecosystems. Moreover, they have also developed protective mechanisms against the immune systems of their hosts. Vibrio species accomplish adaptation to changing environments outside or inside the host by altering their gene expression profiles. To this end, several sigma factors specifically regulate gene expression, particularly under stressful environmental conditions. Moreover, other sigma factors are associated with biofilm formation and virulence as well. This review discusses different types of sigma and anti-sigma factors of Vibrio species involved in virulence and regulation of gene expression upon changes in environmental conditions. The evolutionary relationships between sigma factors with various physiological roles in Vibrio species are also discussed extensively.
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Affiliation(s)
- Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Fazlurrahman Khan
- Institute of Fisheries Sciences, Pukyong National University, Busan 48513, Republic of Korea; Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
| | - Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Young-Mog Kim
- Department of Food Science and Technology, Pukyong National University, Busan 48513, Republic of Korea; Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan 48513, Republic of Korea.
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2
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Guckes KR, Yount TA, Steingard CH, Miyashiro TI. Quorum sensing inhibits interference competition among bacterial symbionts within a host. Curr Biol 2023; 33:4244-4251.e4. [PMID: 37689064 PMCID: PMC10592073 DOI: 10.1016/j.cub.2023.08.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/20/2023] [Accepted: 08/16/2023] [Indexed: 09/11/2023]
Abstract
The symbioses that animals form with bacteria play important roles in health and disease, but the molecular details underlying how bacterial symbionts initially assemble within a host remain unclear.1,2,3 The bioluminescent bacterium Vibrio fischeri establishes a light-emitting symbiosis with the Hawaiian bobtail squid Euprymna scolopes by colonizing specific epithelium-lined crypt spaces within a symbiotic organ called the light organ.4 Competition for these colonization sites occurs between different strains of V. fischeri, with the lancet-like type VI secretion system (T6SS) facilitating strong competitive interference that results in strain incompatibility within a crypt space.5,6 Although recent studies have identified regulators of this T6SS, how the T6SS is controlled as symbionts assemble in vivo remains unknown.7,8 Here, we show that T6SS activity is suppressed by N-octanoyl-L-homoserine lactone (C8 HSL), which is a signaling molecule that facilitates quorum sensing in V. fischeri and is important for efficient symbiont assembly.9,10 We find that this signaling depends on the quorum-sensing regulator LitR, which lowers expression of the needle subunit Hcp, a key component of the T6SS, by repressing transcription of the T6SS regulator VasH. We show that LitR-dependent quorum sensing inhibits strain incompatibility within the squid light organ. Collectively, these results provide new insights into the mechanisms by which regulatory networks that promote symbiosis also control competition among symbionts, which in turn may affect the overall symbiont diversity that assembles within a host.
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Affiliation(s)
- Kirsten R Guckes
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Taylor A Yount
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Caroline H Steingard
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Tim I Miyashiro
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA; The One Health Microbiome Center, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
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3
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Yan J, Guo X, Li J, Li Y, Sun H, Li A, Cao B. RpoN is required for the motility and contributes to the killing ability of Plesiomonas shigelloides. BMC Microbiol 2022; 22:299. [PMID: 36510135 PMCID: PMC9743648 DOI: 10.1186/s12866-022-02722-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 11/30/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND RpoN, also known as σ54, first reported in Escherichia coli, is a subunit of RNA polymerase that strictly controls the expression of different genes by identifying specific promoter elements. RpoN has an important regulatory function in carbon and nitrogen metabolism and participates in the regulation of flagellar synthesis, bacterial motility and virulence. However, little is known about the effect of RpoN in Plesiomonas shigelloides. RESULTS To identify pathways controlled by RpoN, RNA sequencing (RNA-Seq) of the WT and the rpoN deletion strain was carried out for comparison. The RNA-seq results showed that RpoN regulates ~ 13.2% of the P. shigelloides transcriptome, involves amino acid transport and metabolism, glycerophospholipid metabolism, pantothenate and CoA biosynthesis, ribosome biosynthesis, flagellar assembly and bacterial secretion system. Furthermore, we verified the results of RNA-seq using quantitative real-time reverse transcription PCR, which indicated that the absence of rpoN caused downregulation of more than half of the polar and lateral flagella genes in P. shigelloides, and the ΔrpoN mutant was also non-motile and lacked flagella. In the present study, the ability of the ΔrpoN mutant to kill E. coli MG1655 was reduced by 54.6% compared with that of the WT, which was consistent with results in RNA-seq, which showed that the type II secretion system (T2SS-2) genes and the type VI secretion system (T6SS) genes were repressed. By contrast, the expression of type III secretion system genes was largely unchanged in the ΔrpoN mutant transcriptome and the ability of the ΔrpoN mutant to infect Caco-2 cells was also not significantly different compared with the WT. CONCLUSIONS We showed that RpoN is required for the motility and contributes to the killing ability of P. shigelloides and positively regulates the T6SS and T2SS-2 genes.
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Affiliation(s)
- Junxiang Yan
- grid.216938.70000 0000 9878 7032TEDA Institute of Biological Sciences and Biotechnology, Nankai University, No. 23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China
| | - Xueqian Guo
- grid.216938.70000 0000 9878 7032TEDA Institute of Biological Sciences and Biotechnology, Nankai University, No. 23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China
| | - Jinghao Li
- grid.216938.70000 0000 9878 7032TEDA Institute of Biological Sciences and Biotechnology, Nankai University, No. 23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China
| | - Yuehua Li
- grid.216938.70000 0000 9878 7032TEDA Institute of Biological Sciences and Biotechnology, Nankai University, No. 23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China
| | - Hongmin Sun
- grid.216938.70000 0000 9878 7032TEDA Institute of Biological Sciences and Biotechnology, Nankai University, No. 23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China
| | - Ang Li
- grid.216938.70000 0000 9878 7032State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin, 300353 China
| | - Boyang Cao
- grid.216938.70000 0000 9878 7032TEDA Institute of Biological Sciences and Biotechnology, Nankai University, No.23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, No. 23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China ,grid.216938.70000 0000 9878 7032Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, No. 23, Hongda StreetTianjin Economic and Technological Development Area, Tianjin, 300457 China
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Dawan J, Ahn J. Bacterial Stress Responses as Potential Targets in Overcoming Antibiotic Resistance. Microorganisms 2022; 10:microorganisms10071385. [PMID: 35889104 PMCID: PMC9322497 DOI: 10.3390/microorganisms10071385] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/03/2022] [Accepted: 07/08/2022] [Indexed: 12/23/2022] Open
Abstract
Bacteria can be adapted to adverse and detrimental conditions that induce general and specific responses to DNA damage as well as acid, heat, cold, starvation, oxidative, envelope, and osmotic stresses. The stress-triggered regulatory systems are involved in bacterial survival processes, such as adaptation, physiological changes, virulence potential, and antibiotic resistance. Antibiotic susceptibility to several antibiotics is reduced due to the activation of stress responses in cellular physiology by the stimulation of resistance mechanisms, the promotion of a resistant lifestyle (biofilm or persistence), and/or the induction of resistance mutations. Hence, the activation of bacterial stress responses poses a serious threat to the efficacy and clinical success of antibiotic therapy. Bacterial stress responses can be potential targets for therapeutic alternatives to antibiotics. An understanding of the regulation of stress response in association with antibiotic resistance provides useful information for the discovery of novel antimicrobial adjuvants and the development of effective therapeutic strategies to control antibiotic resistance in bacteria. Therefore, this review discusses bacterial stress responses linked to antibiotic resistance in Gram-negative bacteria and also provides information on novel therapies targeting bacterial stress responses that have been identified as potential candidates for the effective control of Gram-negative antibiotic-resistant bacteria.
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Affiliation(s)
- Jirapat Dawan
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
| | - Juhee Ahn
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
- Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Gangwon, Korea
- Correspondence: ; Tel.: +82-33-250-6564
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Host-specific signal perception by PsaR2 LuxR solo induces Pseudomonas syringae pv. actinidiae virulence traits. Microbiol Res 2022; 260:127048. [DOI: 10.1016/j.micres.2022.127048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 03/23/2022] [Accepted: 04/19/2022] [Indexed: 11/19/2022]
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Maharajan AD, Hjerde E, Hansen H, Willassen NP. Quorum Sensing Controls the CRISPR and Type VI Secretion Systems in Aliivibrio wodanis 06/09/139. Front Vet Sci 2022; 9:799414. [PMID: 35211539 PMCID: PMC8861277 DOI: 10.3389/fvets.2022.799414] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/12/2022] [Indexed: 12/26/2022] Open
Abstract
For bacteria to thrive in an environment with competitors, phages and environmental cues, they use different strategies, including Type VI Secretion Systems (T6SSs) and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) to compete for space. Bacteria often use quorum sensing (QS), to coordinate their behavior as the cell density increases. Like other aliivibrios, Aliivibrio wodanis 06/09/139 harbors two QS systems, the main LuxS/LuxPQ system and an N-acyl homoserine lactone (AHL)-mediated AinS/AinR system and a master QS regulator, LitR. To explore the QS and survival strategies, we performed genome analysis and gene expression profiling on A. wodanis and two QS mutants (ΔainS and ΔlitR) at two cell densities (OD600 2.0 and 6.0) and temperatures (6 and 12°C). Genome analysis of A. wodanis revealed two CRISPR systems, one without a cas loci (CRISPR system 1) and a type I-F CRISPR system (CRISPR system 2). Our analysis also identified three main T6SS clusters (T6SS1, T6SS2, and T6SS3) and four auxiliary clusters, as well about 80 potential Type VI secretion effectors (T6SEs). When comparing the wildtype transcriptome data at different cell densities and temperatures, 13-18% of the genes were differentially expressed. The CRISPR system 2 was cell density and temperature-independent, whereas the CRISPR system 1 was temperature-dependent and cell density-independent. The primary and auxiliary clusters of T6SSs were both cell density and temperature-dependent. In the ΔlitR and ΔainS mutants, several CRISPR and T6SS related genes were differentially expressed. Deletion of litR resulted in decreased expression of CRISPR system 1 and increased expression of CRISPR system 2. The T6SS1 and T6SS2 gene clusters were less expressed while the T6SS3 cluster was highly expressed in ΔlitR. Moreover, in ΔlitR, the hcp1 gene was strongly activated at 6°C compared to 12°C. AinS positively affected the csy genes in the CRISPR system 2 but did not affect the CRISPR arrays. Although AinS did not significantly affect the expression of T6SSs, the hallmark genes of T6SS (hcp and vgrG) were AinS-dependent. The work demonstrates that T6SSs and CRISPR systems in A. wodanis are QS dependent and may play an essential role in survival in its natural environment.
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Affiliation(s)
- Amudha Deepalakshmi Maharajan
- Norwegian Structural Biology Center and Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Erik Hjerde
- Norwegian Structural Biology Center and Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway
- Centre for Bioinformatics, Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Hilde Hansen
- Norwegian Structural Biology Center and Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Nils Peder Willassen
- Norwegian Structural Biology Center and Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway
- Centre for Bioinformatics, Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, Tromsø, Norway
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7
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Gallegos-Monterrosa R, Coulthurst SJ. The ecological impact of a bacterial weapon: microbial interactions and the Type VI secretion system. FEMS Microbiol Rev 2021; 45:fuab033. [PMID: 34156081 PMCID: PMC8632748 DOI: 10.1093/femsre/fuab033] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 06/20/2021] [Indexed: 12/13/2022] Open
Abstract
Bacteria inhabit all known ecological niches and establish interactions with organisms from all kingdoms of life. These interactions are mediated by a wide variety of mechanisms and very often involve the secretion of diverse molecules from the bacterial cells. The Type VI secretion system (T6SS) is a bacterial protein secretion system that uses a bacteriophage-like machinery to secrete a diverse array of effectors, usually translocating them directly into neighbouring cells. These effectors display toxic activity in the recipient cell, making the T6SS an effective weapon during inter-bacterial competition and interactions with eukaryotic cells. Over the last two decades, microbiology research has experienced a shift towards using systems-based approaches to study the interactions between diverse organisms and their communities in an ecological context. Here, we focus on this aspect of the T6SS. We consider how our perspective of the T6SS has developed and examine what is currently known about the impact that bacteria deploying the T6SS can have in diverse environments, including niches associated with plants, insects and mammals. We consider how T6SS-mediated interactions can affect host organisms by shaping their microbiota, as well as the diverse interactions that can be established between different microorganisms through the deployment of this versatile secretion system.
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Affiliation(s)
| | - Sarah J Coulthurst
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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8
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Liu X, Pan J, Gao H, Han Y, Zhang A, Huang Y, Liu P, Kan B, Liang W. CqsA/LuxS-HapR Quorum sensing circuit modulates type VI secretion system VflT6SS2 in Vibrio fluvialis. Emerg Microbes Infect 2021; 10:589-601. [PMID: 33689580 PMCID: PMC8018390 DOI: 10.1080/22221751.2021.1902244] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Vibrio fluvialis is an emerging enteric pathogen of increasing public health threat. Two quorum sensing (QS) systems, VfqI-VfqR and CqsA/LuxS-HapR, and two type VI secretion systems (T6SSs), VflT6SS1 and VflT6SS2, have been identified in V. fluvialis. Whether there exists any correlation between the two systems is unclear. In this study, we found that CqsA/LuxS-HapR circuit regulator LuxO represses while HapR activates VflT6SS2. The effect of LuxO is more pronounced at low cell density and is HapR-dependent. Deletion of hapR abolished Hcp expression and alleviated antibacterial virulence. However, these effects were rescued by HapR-expressing plasmid. Reporter fusion analyses showed that HapR is required for the promoter activities of VflT6SS2. Sequence inspection of the major cluster promoter revealed two potential Motif 1 HapR binding sites, and their bindings to HapR were confirmed by both electrophoretic mobility shift assay (EMSA) and DNase I footprinting assay. Meanwhile, two single Motif 2 sites were identified in tssD2_a (hcpA) and tssD2_b (hcpB) promoter regions of the orphan cluster which are less conserved and displayed lower affinities to HapR. Together, our study demonstrated that CqsA/LuxS-HapR QS manipulate VflT6SS2 in V. fluvialis, and this finding will enhance our understanding of possible crosstalk between T6SS and QS in microbes.
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Affiliation(s)
- Xiaoshu Liu
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, People's Republic of China
| | - Jingjing Pan
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, People's Republic of China
| | - He Gao
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, People's Republic of China
| | - Yu Han
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, People's Republic of China
| | - Anran Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, People's Republic of China
| | - Yuanming Huang
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, People's Republic of China
| | - Ping Liu
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, People's Republic of China
| | - Biao Kan
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, People's Republic of China
| | - Weili Liang
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, People's Republic of China
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9
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Zhang N, Zhang S, Ren W, Gong X, Long H, Zhang X, Cai X, Huang A, Xie Z. Roles of rpoN in biofilm formation of Vibrio alginolyticus HN08155 at different cell densities. Microbiol Res 2021; 247:126728. [PMID: 33684638 DOI: 10.1016/j.micres.2021.126728] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 01/14/2021] [Accepted: 02/13/2021] [Indexed: 11/18/2022]
Abstract
RpoN (δ54) as a global regulator controls crucialvirulence-associated phenotype, which can regulate flagellum and exopolysaccharides (EPS) during pathogenic biofilm formation. However, the knowledge of the roles of rpoN in biofilm formation of V. alginolyticus is limited, especially at different cell densities. Herein, deletion mutant strain ΔrpoN, complementary strain ΔrpoN-C and negative control strain ΔrpoN-Z were constructed to investigate the effects of rpoN on biofilm formation of V. alginolyticus HN08155 based on flagellum and EPS at different cell density conditions. The results showed that all of strains can form biofilm, and biofilms of strains with rpoN were formed at low cell density (LCD) and detached at high cell density (HCD), while those of ΔrpoN and ΔrpoN-Z were absent at LCD and accumulated excessively with a spotty pellicle at HCD without detaching. The EPS contents of strains with rpoN was greater than that of ΔrpoN and ΔrpoN-Z at LCD, while the opposite trends were observed at HCD. The expression levels of rpoN were quantified, which were consistent with the trend of biofilm formation. It's worth noting that absence of rpoN resulted in the failure of biofilm detachment, lacking of flagellum and decreasing motility, indicating that rpoN was not necessary for biofilm formation, but it was essential for biofilm detachment.
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Affiliation(s)
- Na Zhang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Shun Zhang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Wei Ren
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Xiaoxiao Gong
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Hao Long
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China
| | - Xiang Zhang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Xiaoni Cai
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Aiyou Huang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Zhenyu Xie
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China.
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10
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Fu S, Ni P, Yang Q, Hu H, Wang Q, Ye S, Liu Y. Delineating the key virulence factors and intraspecies divergence of Vibrio harveyi via whole-genome sequencing. Can J Microbiol 2020; 67:231-248. [PMID: 32941745 DOI: 10.1139/cjm-2020-0079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vibrio harveyi is one of the major pathogens in aquaculture. To identify the key virulence factors affecting pathogenesis of V. harveyi towards fish, we conducted a field investigation for three representative fish farms infected with V. harveyi. Multilocus sequence typing (MLST) and whole-genome sequencing were conducted to delineate the phylogenetic relationship and genetic divergence of V. harveyi. A total of 25 V. harveyi strains were isolated from the diseased fish and groundwater and were subtyped into 12 sequence types by MLST. Five virulence genes, mshB, pilA, hutR, ureB, and ureG, were variably presented in the sequenced strains. The virulence gene profiles strongly correlated with the distinct pathogenicity of V. harveyi strains, with a strain harboring all five genes exhibiting the highest virulence towards fish. Phenotype assay confirmed that reduced virulence correlated with decreased motility and biofilm formation ability. Additionally, three types of type VI secretion system, namely T6SS1, T6SS2, and T6SS3, were identified in V. harveyi strains, which can be classified into six, four, and 12 subtypes, respectively. In conclusion, the results indicated that the virulence level of V. harveyi is mainly determined by the above virulence genes, which may play vital roles in environmental adaptation for V. harveyi.
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Affiliation(s)
- Songzhe Fu
- College of Marine Technology and Environment, Dalian Ocean University, Dalian, P.R. China.,Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian, P.R. China
| | - Ping Ni
- Dalian Key Laboratory of Marine Animal Disease Control and Prevention, Dalian Ocean University, Dalian, P.R. China
| | - Qian Yang
- Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Huizhi Hu
- Hubei Key Laboratory of Regional Development and Environmental Response, School of Resources and Environment, Hubei University, Wuhan, P.R. China
| | - Qingyao Wang
- College of Marine Technology and Environment, Dalian Ocean University, Dalian, P.R. China.,Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian, P.R. China
| | - Shigen Ye
- Dalian Key Laboratory of Marine Animal Disease Control and Prevention, Dalian Ocean University, Dalian, P.R. China
| | - Ying Liu
- College of Marine Technology and Environment, Dalian Ocean University, Dalian, P.R. China.,Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian, P.R. China
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11
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Paraburkholderia phymatum STM815 σ54 Controls Utilization of Dicarboxylates, Motility, and T6SS-b Expression. NITROGEN 2020. [DOI: 10.3390/nitrogen1020008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rhizobia have two major life styles, one as free-living bacteria in the soil, and the other as bacteroids within the root/stem nodules of host legumes where they convert atmospheric nitrogen into ammonia. In the soil, rhizobia have to cope with changing and sometimes stressful environmental conditions, such as nitrogen limitation. In the beta-rhizobial strain Paraburkholderia phymatum STM815, the alternative sigma factor σ54 (or RpoN) has recently been shown to control nitrogenase activity during symbiosis with Phaseolus vulgaris. In this study, we determined P. phymatum’s σ54 regulon under nitrogen-limited free-living conditions. Among the genes significantly downregulated in the absence of σ54, we found a C4-dicarboxylate carrier protein (Bphy_0225), a flagellar biosynthesis cluster (Bphy_2926-64), and one of the two type VI secretion systems (T6SS-b) present in the P. phymatum STM815 genome (Bphy_5978-97). A defined σ54 mutant was unable to grow on C4 dicarboxylates as sole carbon source and was less motile compared to the wild-type strain. Both defects could be complemented by introducing rpoNin trans. Using promoter reporter gene fusions, we also confirmed that the expression of the T6SS-b cluster is regulated by σ54. Accordingly, we show that σ54 affects in vitro competitiveness of P. phymatum STM815 against Paraburkholderia diazotrophica.
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12
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Cellini A, Donati I, Fiorentini L, Vandelle E, Polverari A, Venturi V, Buriani G, Vanneste JL, Spinelli F. N-Acyl Homoserine Lactones and Lux Solos Regulate Social Behaviour and Virulence of Pseudomonas syringae pv. actinidiae. MICROBIAL ECOLOGY 2020; 79:383-396. [PMID: 31359073 DOI: 10.1007/s00248-019-01416-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 07/16/2019] [Indexed: 06/10/2023]
Abstract
The phyllosphere is a complex environment where microbes communicate through signalling molecules in a system, generally known as quorum sensing (QS). One of the most common QS systems in Gram-negative proteobacteria is based on the production of N-acyl homoserine lactones (AHLs) by a LuxI synthase and their perception by a LuxR sensor. Pseudomonas syringae pv. actinidiae (Psa), the aetiological agent of the bacterial canker of kiwifruit, colonises plant phyllosphere before penetrating via wounds and natural openings. Since Psa genome encodes three LuxR solos without a cognate LuxI, this bacterium may perceive diffusible signals, but it cannot produce AHLs, displaying a non-canonical QS system. The elucidation of the mechanisms underlying the perception of environmental cues in the phyllosphere by this pathogen and their influence on the onset of pathogenesis are of crucial importance for a long-lasting and sustainable management of the bacterial canker of kiwifruit. Here, we report the ability of Psa to sense its own population density and the presence of surrounding bacteria. Moreover, we show that Psa can perceive AHLs, indicating that AHL-producing neighbouring bacteria may regulate Psa virulence in the host. Our results suggest that the ecological environment is important in determining Psa fitness and pathogenic potential. This opens new perspectives in the use of more advanced biochemical and microbiological tools for the control of bacterial canker of kiwifruit.
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Affiliation(s)
- Antonio Cellini
- Department of Agricultural and Food Science, Alma Mater Studiorum - Università di Bologna, Viale Fanin 44, 40127, Bologna, Italy
| | - Irene Donati
- Department of Agricultural and Food Science, Alma Mater Studiorum - Università di Bologna, Viale Fanin 44, 40127, Bologna, Italy
| | - Luca Fiorentini
- Department of Agricultural and Food Science, Alma Mater Studiorum - Università di Bologna, Viale Fanin 44, 40127, Bologna, Italy
| | - Elodie Vandelle
- Department of Biotechnology, Università degli Studi di Verona, Verona, Italy
| | - Annalisa Polverari
- Department of Biotechnology, Università degli Studi di Verona, Verona, Italy
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Giampaolo Buriani
- Department of Agricultural and Food Science, Alma Mater Studiorum - Università di Bologna, Viale Fanin 44, 40127, Bologna, Italy
| | - Joel L Vanneste
- The New Zealand Institute for Plant & Food Research, Hamilton, New Zealand
| | - Francesco Spinelli
- Department of Agricultural and Food Science, Alma Mater Studiorum - Università di Bologna, Viale Fanin 44, 40127, Bologna, Italy.
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13
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The Ferric Uptake Regulator Represses Type VI Secretion System Function by Binding Directly to the clpV Promoter in Salmonella enterica Serovar Typhimurium. Infect Immun 2019; 87:IAI.00562-19. [PMID: 31383745 DOI: 10.1128/iai.00562-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 07/25/2019] [Indexed: 12/16/2022] Open
Abstract
Type VI secretion systems (T6SSs) are highly conserved and complex protein secretion systems that deliver effector proteins into eukaryotic hosts or other bacteria. T6SSs are regulated precisely by a variety of regulatory systems, which enables bacteria to adapt to varied environments. A T6SS within Salmonella pathogenicity island 6 (SPI-6) is activated during infection, and it contributes to the pathogenesis, as well as interbacterial competition, of Salmonella enterica serovar Typhimurium (S. Typhimurium). However, the regulation of the SPI-6 T6SS in S. Typhimurium is not well understood. In this study, we found that the SPI-6 T6SS core gene clpV was significantly upregulated in response to the iron-depleted condition and during infection. The global ferric uptake regulator (Fur) was shown to repress the clpV expression in the iron-replete medium. Moreover, electrophoretic mobility shift and DNase I footprinting assays revealed that Fur binds directly to the clpV promoter region at multiple sites spanning the transcriptional start site. We also observed that the relieving of Fur-mediated repression on clpV contributed to the interbacterial competition activity and pathogenicity of S. Typhimurium. These findings provide insights into the direct regulation of Fur in the expression and functional activity of SPI-6 T6SS in S. Typhimurium and thus help to elucidate the mechanisms of bacterial adaptability and virulence.
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14
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Chen C, Yang X, Shen X. Confirmed and Potential Roles of Bacterial T6SSs in the Intestinal Ecosystem. Front Microbiol 2019; 10:1484. [PMID: 31316495 PMCID: PMC6611333 DOI: 10.3389/fmicb.2019.01484] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 06/14/2019] [Indexed: 12/25/2022] Open
Abstract
The contact-dependent type VI secretion system (T6SS) in diverse microbes plays crucial roles in both inter-bacterial and bacteria-host interactions. As numerous microorganisms inhabit the intestinal ecosystem at a high density, it is necessary to consider the functions of T6SS in intestinal bacteria. In this mini-review, we discuss T6SS-dependent functions in intestinal microbes, including commensal microbes and enteric pathogens, and list experimentally verified species of intestinal bacteria containing T6SS clusters. Several seminal studies have shown that T6SS plays crucial antibacterial roles in colonization resistance, niche occupancy, activation of host innate immune responses, and modulation of host intestinal mechanics. Some potential roles of T6SS in the intestinal ecosystem, such as targeting of single cell eukaryotic competitors, competition for micronutrients, and stress resistance are also discussed. Considering the distinct activities of T6SS in diverse bacteria residing in the intestine, we suggest that T6SS research in intestinal microbes may be beneficial for the future development of new medicines and clinical treatments.
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Affiliation(s)
- Can Chen
- Institute of Food and Drug Inspection, College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, China
| | - Xiaobing Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, 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, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
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15
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Pena RT, Blasco L, Ambroa A, González-Pedrajo B, Fernández-García L, López M, Bleriot I, Bou G, García-Contreras R, Wood TK, Tomás M. Relationship Between Quorum Sensing and Secretion Systems. Front Microbiol 2019; 10:1100. [PMID: 31231316 PMCID: PMC6567927 DOI: 10.3389/fmicb.2019.01100] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/30/2019] [Indexed: 01/15/2023] Open
Abstract
Quorum sensing (QS) is a communication mechanism between bacteria that allows specific processes to be controlled, such as biofilm formation, virulence factor expression, production of secondary metabolites and stress adaptation mechanisms such as bacterial competition systems including secretion systems (SS). These SS have an important role in bacterial communication. SS are ubiquitous; they are present in both Gram-negative and Gram-positive bacteria and in Mycobacterium sp. To date, 8 types of SS have been described (T1SS, T2SS, T3SS, T4SS, T5SS, T6SS, T7SS, and T9SS). They have global functions such as the transport of proteases, lipases, adhesins, heme-binding proteins, and amidases, and specific functions such as the synthesis of proteins in host cells, adaptation to the environment, the secretion of effectors to establish an infectious niche, transfer, absorption and release of DNA, translocation of effector proteins or DNA and autotransporter secretion. All of these functions can contribute to virulence and pathogenesis. In this review, we describe the known types of SS and discuss the ones that have been shown to be regulated by QS. Due to the large amount of information about this topic in some pathogens, we focus mainly on Pseudomonas aeruginosa and Vibrio spp.
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Affiliation(s)
- Rocio Trastoy Pena
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Lucia Blasco
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Antón Ambroa
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Laura Fernández-García
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Maria López
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Ines Bleriot
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - German Bou
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
| | - Rodolfo García-Contreras
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Thomas Keith Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Maria Tomás
- Deapartamento de Microbiología y Parasitología, Complejo Hospitalario Universitario A Coruña (CHUAC), Instituto de Investigación Biomédica (INIBIC), Universidad de A Coruña (UDC), A Coruña, Spain
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16
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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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17
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Zhang Y, Gao H, Osei-Adjei G, Zhang Y, Yang W, Yang H, Yin Z, Huang X, Zhou D. Transcriptional Regulation of the Type VI Secretion System 1 Genes by Quorum Sensing and ToxR in Vibrio parahaemolyticus. Front Microbiol 2017; 8:2005. [PMID: 29085350 PMCID: PMC5650642 DOI: 10.3389/fmicb.2017.02005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/29/2017] [Indexed: 12/26/2022] Open
Abstract
Vibrio parahaemolyticus, the leading cause of seafood-associated gastroenteritis, harbors two separate T6SSs on chromosomes 1 and 2, i.e., T6SS1 (VP1386-1420) and T6SS2 (VPA1025-1046). T6SS1 contains at least 7 putative operons: VP1386-1387, VP1388-1390, VP1392-1391, VP1393-1406, VP1400-1406, VP1409-1407, and VP1410-1420. V. parahaemolyticus AphA and OpaR are the two master regulators of quorum sensing (QS) system that are highly expressed at low cell density and high cell density, respectively. ToxR is a membrane-bound virulence regulatory protein conserved across the Vibrio family. In the present work, we show that ToxR coordinates with AphA and OpaR to repress T6SS1 expression in V. parahaemolyticus. OpaR binds to the promoters of VP1388-1390, VP1400-1406, and VP1409-1407 to repress their transcription, but it appears to negatively regulate VP1393-1406 transcription in an indirect manner. By contrast, AphA negatively regulated the above four T6SS1 operons in an indirect manner. In addition, ToxR binds to the promoters of VP1400-1406 and VP1409-1407 to inhibit their transcription, but it presents an indirect interaction with VP1388-1390 and VP1393-1406 promoters. Notably, the expression of ToxR also manifested in a QS-dependent manner and the highest expression occurred at LCD. Meanwhile, the highest expression of T6SS1 occurred at an OD600 value of 0.6 to 0.8 due to the tight regulation of ToxR and QS, suggesting T6SS1 functions only during the mid-logarithmic growth phase. These observations provide significant insight into the molecular mechanism of T6SS1 gene regulation by QS and ToxR in V. parahaemolyticus.
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Affiliation(s)
- Yiquan Zhang
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - He Gao
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Centre for Disease Control and Prevention, Beijing, China
| | | | - Ying Zhang
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Wenhui Yang
- Department of Biosafety, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Huiying Yang
- Department of Biosafety, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhe Yin
- Department of Biosafety, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Xinxiang Huang
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Dongsheng Zhou
- Department of Biosafety, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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18
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Huang Y, Du P, Zhao M, Liu W, Du Y, Diao B, Li J, Kan B, Liang W. Functional Characterization and Conditional Regulation of the Type VI Secretion System in Vibrio fluvialis. Front Microbiol 2017; 8:528. [PMID: 28424671 PMCID: PMC5371669 DOI: 10.3389/fmicb.2017.00528] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 03/14/2017] [Indexed: 01/22/2023] Open
Abstract
Vibrio fluvialis is an emerging foodborne pathogen of increasing public health concern. The mechanism(s) that contribute to the bacterial survival and disease are still poorly understood. In other bacterial species, type VI secretion systems (T6SSs) are known to contribute to bacterial pathogenicity by exerting toxic effects on host cells or competing bacterial species. In this study, we characterized the genetic organization and prevalence of two T6SS gene clusters (VflT6SS1 and VflT6SS2) in V. fluvialis. VflT6SS2 harbors three “orphan” hcp-vgrG modules and was more prevalent than VflT6SS1 in our isolates. We showed that VflT6SS2 is functionally active under low (25°C) and warm (30°C) temperatures by detecting the secretion of a T6SS substrate, Hcp. This finding suggests that VflT6SS2 may play an important role in the survival of the bacterium in the aquatic environment. The secretion of Hcp is growth phase-dependent and occurs in a narrow range of the growth phase (OD600 from 1.0 to 2.0). Osmolarity also regulates the function of VflT6SS2, as evidenced by our finding that increasing salinity (from 170 to 855 mM of NaCl) and exposure to high osmolarity KCl, sucrose, trehalose, or mannitol (equivalent to 340 mM of NaCl) induced significant secretion of Hcp under growth at 30°C. Furthermore, we found that although VflT6SS2 was inactive at a higher temperature (37°C), it became activated at this temperature if higher salinity conditions were present (from 513 to 855 mM of NaCl), indicating that it may be able to function under certain conditions in the infected host. Finally, we showed that the functional expression of VflT6SS2 is associated with anti-bacterial activity. This activity is Hcp-dependent and requires vasH, a transcriptional regulator of T6SS. In sum, our study demonstrates that VflT6SS2 provides V. fluvialis with an enhanced competitive fitness in the marine environment, and its activity is regulated by environmental signals, such as temperature and osmolarity.
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Affiliation(s)
- Yuanming Huang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China.,Collaborative Innovation Centre for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
| | - Pengcheng Du
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical UniversityBeijing, China
| | - Meng Zhao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Wei Liu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Yu Du
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Baowei Diao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Jie Li
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Biao Kan
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China.,Collaborative Innovation Centre for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
| | - Weili Liang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China.,Collaborative Innovation Centre for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
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19
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Sasikala D, Jeyakanthan J, Srinivasan P. Structure-based virtual screening and biological evaluation of LuxT inhibitors for targeting quorum sensing through an in vitro biofilm formation. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.07.118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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20
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Sasikala D, Srinivasan P. Characterization of potential lytic bacteriophage against Vibrio alginolyticus and its therapeutic implications on biofilm dispersal. Microb Pathog 2016; 101:24-35. [PMID: 27793690 DOI: 10.1016/j.micpath.2016.10.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 10/18/2016] [Accepted: 10/25/2016] [Indexed: 11/25/2022]
Abstract
Vibrio alginolyticus is a leading cause of vibriosis, presenting opportunistic infections to humans associated with raw seafood contamination. At present, phage therapy that acts as an alternative sanitizing agent is explored for targeting V. alginolyticus. The study outcome revealed that the phage VP01 with its extreme lytic effect showed a high potential impact on the growth of V. alginolyticus as well as biofilm formation. Electron microscopy revealed the phage resemblance to Myoviridae, based on its morphology. Further study clarified that the phage VP01 possesses a broad host spectrum and amazing phage sensitivity at different pH, high thermal stability, and high burst size of 415 PFU/cell. In addition, the investigation of phage co-culturing against this pathogen resulted in a significant growth reduction even at less MOIs 0.1 and 1. These results suggest that the phage could be a promising candidate for the control of V. alginolyticus infections.
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Affiliation(s)
- Dakshinamurthy Sasikala
- Department of Bioinformatics, Science Campus, Alagappa University, Karaikudi, Tamil Nadu, India
| | - Pappu Srinivasan
- Department of Animal Health and Management, Science Campus, Alagappa University, Karaikudi, Tamil Nadu, India.
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Wang P, Wen Z, Li B, Zeng Z, Wang X. Complete genome sequence of Vibrio alginolyticus ATCC 33787(T) isolated from seawater with three native megaplasmids. Mar Genomics 2016; 28:45-47. [PMID: 27211073 DOI: 10.1016/j.margen.2016.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 10/21/2022]
Abstract
Vibrio alginolyticus, an opportunistic pathogen, is commonly associated with vibriosis in fish and shellfish and can also cause superficial and ear infections in humans. V. alginolyticus ATCC 33787(T) was originally isolated from seawater and has been used as one of the type strains for exploring the virulence factors of marine bacteria and for developing vaccine against vibriosis. Here we sequenced and assembled the whole genome of this strain, and identified three megaplasmids and three Type VI secretion systems, thus providing useful information for the study of virulence factors and for the development of vaccine for Vibrio.
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Affiliation(s)
- Pengxia Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, the South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Zhongling Wen
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, the South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baiyuan Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, the South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhenshun Zeng
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, the South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, the South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
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Majerczyk C, Schneider E, Greenberg EP. Quorum sensing control of Type VI secretion factors restricts the proliferation of quorum-sensing mutants. eLife 2016; 5. [PMID: 27183270 PMCID: PMC4868534 DOI: 10.7554/elife.14712] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/08/2016] [Indexed: 12/12/2022] Open
Abstract
Burkholderia thailandensis uses acyl-homoserine lactone-mediated quorum sensing systems to regulate hundreds of genes. Here we show that cell-cell contact-dependent type VI secretion (T6S) toxin-immunity systems are among those activated by quorum sensing in B. thailandensis. We also demonstrate that T6S is required to constrain proliferation of quorum sensing mutants in colony cocultures of a BtaR1 quorum-sensing signal receptor mutant and its parent. However, the BtaR1 mutant is not constrained by and outcompetes its parent in broth coculture, presumably because no cell contact occurs and there is a metabolic cost associated with quorum sensing gene activation. The increased fitness of the wild type over the BtaR1 mutant during agar surface growth is dependent on an intact T6SS-1 apparatus. Thus, quorum sensing activates B. thailandensis T6SS-1 growth inhibition and this control serves to police and constrain quorum-sensing mutants. This work defines a novel role for T6SSs in intraspecies mutant control. DOI:http://dx.doi.org/10.7554/eLife.14712.001 Bacterial cells communicate with each other by using chemical signals. The signals allow cells living in a group to coordinate their behaviors. This cooperation can help all the cells in the group, yet scientists are puzzled about how it could evolve and persist in a population. This is because individual bacteria that essentially cheat and benefit from the cooperation of the rest of the group without contributing their fair share would have a fitness advantage. Now, Majerczyk et al. show that a bacterium called Burkholderia thailandensis, which is commonly found in soil, poisons neighboring freeloaders to prevent such cheating. In the experiments, bacteria with mutations that allow them to ignore the chemical signals that trigger cooperation have an advantage over cooperative bacteria when the two types of bacteria are grown together in a liquid. However, the uncooperative mutants lose their advantage when they are grown on a surface where the cooperative bacteria touch them. To understand why, Majerczyk et al. examined which genes were active in both types of cells in these situations. These experiments showed that chemical signals released by the cooperative bacteria cause them to produce both toxins and proteins that protect against these toxins. This allows the cooperative cells to poison cheaters that they come in contact with, while suffering no ill effects themselves. This allows the cooperative bacteria, via the signaling chemicals, to police cheats and reward only other cooperative bacteria. The next step will be to determine if other types of bacteria also use this policing strategy and to identify more pairs of genes that contribute to protecting the benefits of cooperation. DOI:http://dx.doi.org/10.7554/eLife.14712.002
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Affiliation(s)
- Charlotte Majerczyk
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Emily Schneider
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - E Peter Greenberg
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States.,Guangdong Innovative and Entrepreneurial Research Team of Sociomicrobiology Basic Science and Frontier Technology, South China Agricultural University, Guangzhou, China
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Expression, secretion and bactericidal activity of type VI secretion system in Vibrio anguillarum. Arch Microbiol 2016; 198:751-60. [DOI: 10.1007/s00203-016-1236-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/21/2016] [Accepted: 05/05/2016] [Indexed: 10/21/2022]
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Zhao J, Chen M, Quan CS, Fan SD. Mechanisms of quorum sensing and strategies for quorum sensing disruption in aquaculture pathogens. JOURNAL OF FISH DISEASES 2015; 38:771-786. [PMID: 25219871 DOI: 10.1111/jfd.12299] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 07/02/2014] [Accepted: 07/07/2014] [Indexed: 06/03/2023]
Abstract
In many countries, infectious diseases are a considerable threat to aquaculture. The pathogenicity of micro-organisms that infect aquaculture systems is closely related to the release of virulence factors and the formation of biofilms, both of which are regulated by quorum sensing (QS). Thus, QS disruption is a potential strategy for preventing disease in aquaculture systems. QS inhibitors (QSIs) not only inhibit the expression of virulence-associated genes but also attenuate the virulence of aquaculture pathogens. In this review, we discuss QS systems in important aquaculture pathogens and focus on the relationship between QS mechanisms and bacterial virulence in aquaculture. We further elucidate QS disruption strategies for targeting aquaculture pathogens. Four main types of QSIs that target aquaculture pathogens are discussed based on their mechanisms of action.
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Affiliation(s)
- J Zhao
- Key Laboratory of Biochemical Engineering State Ethnic Affairs Commission-Ministry of Education, Dalian Nationalities University, Dalian, China
- College of Life Science, Dalian Nationalities University, Dalian, China
| | - M Chen
- College of Bioengineering, Dalian Polytechnic University, Dalian, China
| | - C S Quan
- Key Laboratory of Biochemical Engineering State Ethnic Affairs Commission-Ministry of Education, Dalian Nationalities University, Dalian, China
- College of Life Science, Dalian Nationalities University, Dalian, China
| | - S D Fan
- Key Laboratory of Biochemical Engineering State Ethnic Affairs Commission-Ministry of Education, Dalian Nationalities University, Dalian, China
- College of Life Science, Dalian Nationalities University, Dalian, China
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Salomon D, Klimko JA, Trudgian DC, Kinch LN, Grishin NV, Mirzaei H, Orth K. Type VI Secretion System Toxins Horizontally Shared between Marine Bacteria. PLoS Pathog 2015; 11:e1005128. [PMID: 26305100 PMCID: PMC4549250 DOI: 10.1371/journal.ppat.1005128] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 08/04/2015] [Indexed: 11/19/2022] Open
Abstract
The type VI secretion system (T6SS) is a widespread protein secretion apparatus used by Gram-negative bacteria to deliver toxic effector proteins into adjacent bacterial or host cells. Here, we uncovered a role in interbacterial competition for the two T6SSs encoded by the marine pathogen Vibrio alginolyticus. Using comparative proteomics and genetics, we identified their effector repertoires. In addition to the previously described effector V12G01_02265, we identified three new effectors secreted by T6SS1, indicating that the T6SS1 secretes at least four antibacterial effectors, of which three are members of the MIX-effector class. We also showed that the T6SS2 secretes at least three antibacterial effectors. Our findings revealed that many MIX-effectors belonging to clan V are “orphan” effectors that neighbor mobile elements and are shared between marine bacteria via horizontal gene transfer. We demonstrated that a MIX V-effector from V. alginolyticus is a functional T6SS effector when ectopically expressed in another Vibrio species. We propose that mobile MIX V-effectors serve as an environmental reservoir of T6SS effectors that are shared and used to diversify antibacterial toxin repertoires in marine bacteria, resulting in enhanced competitive fitness. The bacterial type VI secretion system (T6SS) is a contact-dependent protein secretion apparatus that is emerging as a major component of interbacterial competition in the environment. The bacterium Vibrio alginolyticus is a pathogen of marine animals and a causal agent of wound infections, otitis, and gastroenteritis in humans. In this study, we provide a comprehensive characterization of the environmental regulation, antibacterial activities, and secreted effector repertoires of the two T6SSs found in this pathogen. We also identify a subset of T6SS effectors that appear to be mobile and shared between marine bacteria that can interact with each other in aquatic environments. Our findings suggest that bacteria can incorporate T6SS effectors from competitors in the environment. These newly acquired toxins may be used to expand and diversify T6SS effector repertoires and enhance bacterial fitness.
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Affiliation(s)
- Dor Salomon
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail: (DS); (KO)
| | - John A. Klimko
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - David C. Trudgian
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Lisa N. Kinch
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Nick V. Grishin
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Hamid Mirzaei
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail: (DS); (KO)
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26
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Mitra A, Fay PA, Vendura KW, Alla Z, Carroll RK, Shaw LN, Riordan JT. σ(N) -dependent control of acid resistance and the locus of enterocyte effacement in enterohemorrhagic Escherichia coli is activated by acetyl phosphate in a manner requiring flagellar regulator FlhDC and the σ(S) antagonist FliZ. Microbiologyopen 2014; 3:497-512. [PMID: 24931910 PMCID: PMC4287178 DOI: 10.1002/mbo3.183] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 04/30/2014] [Accepted: 05/15/2014] [Indexed: 12/02/2022] Open
Abstract
In enterohemorrhagic Escherichia coli (EHEC), sigma factor N (σN) regulates glutamate-dependent acid resistance (GDAR) and the locus of enterocyte effacement (LEE); discrete genetic systems that are required for transmission and virulence of this intestinal pathogen. Regulation of these systems requires nitrogen regulatory protein C, NtrC, and is a consequence of NtrC-σN-dependent reduction in the activity of sigma factor S (σS). This study elucidates pathway components and stimuli for σN-directed regulation of GDAR and the LEE in EHEC. Deletion of fliZ, the product of which reduces σS activity, phenocopied rpoN (σN) and ntrC null strains for GDAR and LEE control, acid resistance, and adherence. Upregulation of fliZ by NtrC-σN was shown to be indirect and required an intact flagellar regulator flhDC. Activation of flhDC by NtrC-σN and FlhDC-dependent regulation of GDAR and the LEE was dependent on σN-promoter flhDP2, and a newly described NtrC upstream activator sequence. Addition of ammonium chloride significantly altered expression of GDAR and LEE, acid resistance, and adherence, independently of rpoN, ntrC, and the NtrC sensor kinase, ntrB. Altering the availability of NtrC phosphodonor acetyl phosphate by growth without glucose, with acetate addition, or by deletion of acetate kinase ackA, abrogated NtrC-σN-dependent control of flhDC, fliZ, GDAR, and the LEE.
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Affiliation(s)
- Avishek Mitra
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida, 33620
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27
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Abstract
Bacteria use diverse mechanisms to kill, manipulate, and compete with other cells. The recently discovered type VI secretion system (T6SS) is widespread in bacterial pathogens and used to deliver virulence effector proteins into target cells. Using comparative proteomics, we identified two previously unidentified T6SS effectors that contained a conserved motif. Bioinformatic analyses revealed that this N-terminal motif, named MIX (marker for type six effectors), is found in numerous polymorphic bacterial proteins that are primarily located in the T6SS genome neighborhood. We demonstrate that several MIX-containing proteins are T6SS effectors and that they are not required for T6SS activity. Thus, we propose that MIX-containing proteins are T6SS effectors. Our findings allow for the identification of numerous uncharacterized T6SS effectors that will undoubtedly lead to the discovery of new biological mechanisms.
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Wang L, Zhou D, Mao P, Zhang Y, Hou J, Hu Y, Li J, Hou S, Yang R, Wang R, Qiu J. Cell density- and quorum sensing-dependent expression of type VI secretion system 2 in Vibrio parahaemolyticus. PLoS One 2013; 8:e73363. [PMID: 23977385 PMCID: PMC3744643 DOI: 10.1371/journal.pone.0073363] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 07/18/2013] [Indexed: 12/19/2022] Open
Abstract
Background Vibrio parahaemolyticus AphA and OpaR are the two master quorum sensing (QS) regulators that are abundantly expressed at low cell density (LCD) and high cell density (HCD), respectively, with a feature of reciprocally gradient production of them with transition between LCD and HCD. The type VI secretion system 2 (T6SS2) gene cluster can be assigned into three putative operons, namely VPA1027-1024, VPA1043-1028, and VPA1044-1046. T6SS2 contributes to adhesion of V. parahaemolyticus to host cells. Methodology/Principal Findings OpaR box-like sequences were found within the upstream promoter regions of all the above three operons, while none of AphA box-like elements could be identified for them. The subsequent primer extension, LacZ fusion, electrophoretic mobility shift, and DNase I footprinting assays disclosed that OpaR bound to the promoter regions of these three operons to stimulate their transcription, while AphA negatively regulated their transcription most likely through acting on OpaR. This regulation led to a gradient increase of T6SS2 transcription with transition from LCD to HCD. Conclusions/Significance V. parahaemolyticus OpaR and AphA positively and negatively regulate T6SS2 expression, respectively, leading to a gradient elevation of T6SS2 expression with transition from LCD to HCD. T6SS2 genes are thus assigned as the QS regulon members in V. parahaemolyticus.
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Affiliation(s)
- Li Wang
- School of Public Health, Chongqing Medical University, Chongqing, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- Beijing 302 Hospital, Beijing, China
| | | | - Yiquan Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Jun Hou
- Beijing 302 Hospital, Beijing, China
| | - Yan Hu
- Beijing 302 Hospital, Beijing, China
| | - Jin Li
- Beijing 302 Hospital, Beijing, China
| | | | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Runhua Wang
- School of Public Health, Chongqing Medical University, Chongqing, China
| | - Jingfu Qiu
- School of Public Health, Chongqing Medical University, Chongqing, China
- * E-mail:
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29
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Sheng L, Lv Y, Liu Q, Wang Q, Zhang Y. Connecting type VI secretion, quorum sensing, and c-di-GMP production in fish pathogen Vibrio alginolyticus through phosphatase PppA. Vet Microbiol 2013; 162:652-662. [PMID: 23021863 DOI: 10.1016/j.vetmic.2012.09.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 09/03/2012] [Accepted: 09/04/2012] [Indexed: 11/29/2022]
Abstract
Vibrio alginolyticus, a Gram-negative marine bacterium, has brought about severe economic damage to the mariculture industry by causing vibriosis in various fish species. We are intrigued in the regulation of the pathogenesis in this bacterium. Here, we reported a complex regulatory connection among the newly defined type VI secretion system (T6SS), quorum sensing (QS), and 3',5'-cyclic diguanylic acid (c-di-GMP) signal through the phosphatase PppA encoded in the T6SS gene cluster of V. alginolyticus. Whole-genome transcriptome analysis revealed various regulatory targets of PppA including the T6SS substrate hemolysin coregulated protein (Hcp), quorum sensing regulator LuxR, exotoxin alkaline serine protease (Asp), flagellar proteins, as well as proteins involved in polysaccharide biosynthesis and transport. Western blot analysis showed PppA served as a negative regulator of the expression and secretion of Hcp1. Mutation of pppA resulted in an increased level of the intracellular second messenger c-di-GMP and a decreased expression of the QS regulator LuxR as well as exotoxin Asp. Complementation of intact pppA gene in ΔpppA mutant restored the production of c-di-GMP, LuxR, and Asp to the wild-type level. Phenotypic studies suggested that PppA takes part in the modulation of biofilm formation, motility, and cell aggregation. These results demonstrated new roles of PppA in controlling virulence factors and pleiotropic phenotypes and contributed to our understanding of the regulation of pathogenesis in V. alginolyticus.
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Affiliation(s)
- Lili Sheng
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Yuanzhi Lv
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Qin Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
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Miyata ST, Bachmann V, Pukatzki S. Type VI secretion system regulation as a consequence of evolutionary pressure. J Med Microbiol 2013; 62:663-676. [PMID: 23429693 DOI: 10.1099/jmm.0.053983-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The type VI secretion system (T6SS) is a mechanism evolved by Gram-negative bacteria to negotiate interactions with eukaryotic and prokaryotic competitors. T6SSs are encoded by a diverse array of bacteria and include plant, animal, human and fish pathogens, as well as environmental isolates. As such, the regulatory mechanisms governing T6SS gene expression vary widely from species to species, and even from strain to strain within a given species. This review concentrates on the four bacterial genera that the majority of recent T6SS regulatory studies have been focused on: Vibrio, Pseudomonas, Burkholderia and Edwardsiella.
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Affiliation(s)
- Sarah T Miyata
- Department of Medical Microbiology and Immunology, 6-22 Heritage Medical Research Centre, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Verena Bachmann
- Department of Medical Microbiology and Immunology, 6-22 Heritage Medical Research Centre, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Stefan Pukatzki
- Department of Medical Microbiology and Immunology, 6-22 Heritage Medical Research Centre, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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Ma L, Zhang Y, Yan X, Guo L, Wang L, Qiu J, Yang R, Zhou D. Expression of the type VI secretion system 1 component Hcp1 is indirectly repressed by OpaR in Vibrio parahaemolyticus. ScientificWorldJournal 2012; 2012:982140. [PMID: 22924031 PMCID: PMC3417189 DOI: 10.1100/2012/982140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 05/07/2012] [Indexed: 01/09/2023] Open
Abstract
The type VI secretion system (T6SS) is bacterial protein injection machinery with roles in virulence, symbiosis, interbacterial interaction, antipathogenesis, and environmental stress responses. There are two T6SS loci, T6SS1 and T6SS2, in the two chromosomes of Vibrio parahaemolyticus, respectively. This work disclosed that the master quorum sensing (QS) regulator OpaR repressed the transcription of hcp1 encoding the structural component Hcp1 of T6SS1 in V. parahaemolyticus, indicating that QS had a negative regulatory action on T6SS1. A single σ54-dependent promoter was transcribed for hcp1 in V. parahaemolyticus, and its activity was repressed by the OpaR regulator. Since the OpaR protein could not bind to the upstream region of hcp1, OpaR would repress the transcription of hcp1 in an indirect manner.
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Affiliation(s)
- Lizhi Ma
- Department of Emergency Medicine, General Hospital of Chinese People's Armed Police Forces, Beijing 100039, China
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32
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Liu H, Gu D, Sheng L, Wang Q, Zhang Y. Investigation of the roles of T6SS genes in motility, biofilm formation, and extracellular protease Asp production in Vibrio alginolyticus with modified Gateway-compatible plasmids. Lett Appl Microbiol 2012; 55:73-81. [PMID: 22563695 DOI: 10.1111/j.1472-765x.2012.03263.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
AIMS The aims of this study were to create and evaluate the Gateway-compatible plasmids for investigating the function of genes in Vibrio alginolyticus and other Gram-negative bacteria. METHODS AND RESULTS In this study, Gateway-compatible plasmids were successfully constructed for rapid and comprehensive function analysis of genes. Taking advantage of these plasmids, the in-frame deletion mutant strains and their complemented strains of five T6SS genes, including dotU1, VEPGS_0008, VEPGS_0011, hcp2 and ppkA2, were obtained. The results illustrated that all the mutant strains showed no significant effects on extracellular protease production, expression of Hcp1, and biofilm formation when compared to the wild-type strain, but in-frame deletion of VEPGS_0008 resulted in obvious biofilm reduction and the complemented strain restored to the level of the wild-type strain. Besides, in-frame deletion of dotU1, VEPGS_0008 and ppkA2 abolished the swarming ability. CONCLUSIONS A set of Gateway-compatible vectors for internal insertion, in-frame deletion and complementation of the target genes is constructed to facilitate the general and rapid function analysis of genes involved in T6SS in Vibrio alginolyticus. SIGNIFICANCE AND IMPACT OF THE STUDY The modified Gateway-compatible plasmids greatly facilitate the high-throughput and convenient function analysis of the unidentified genes.
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Affiliation(s)
- H Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
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