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Potapova A, Garvey W, Dahl P, Guo S, Chang Y, Schwechheimer C, Trebino MA, Floyd KA, Phinney BS, Liu J, Malvankar NS, Yildiz FH. Outer membrane vesicles and the outer membrane protein OmpU govern Vibrio cholerae biofilm matrix assembly. mBio 2024; 15:e0330423. [PMID: 38206049 PMCID: PMC10865864 DOI: 10.1128/mbio.03304-23] [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: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 01/12/2024] Open
Abstract
Biofilms are matrix-encased microbial communities that increase the environmental fitness and infectivity of many human pathogens including Vibrio cholerae. Biofilm matrix assembly is essential for biofilm formation and function. Known components of the V. cholerae biofilm matrix are the polysaccharide Vibrio polysaccharide (VPS), matrix proteins RbmA, RbmC, Bap1, and extracellular DNA, but the majority of the protein composition is uncharacterized. This study comprehensively analyzed the biofilm matrix proteome and revealed the presence of outer membrane proteins (OMPs). Outer membrane vesicles (OMVs) were also present in the V. cholerae biofilm matrix and were associated with OMPs and many biofilm matrix proteins suggesting that they participate in biofilm matrix assembly. Consistent with this, OMVs had the capability to alter biofilm structural properties depending on their composition. OmpU was the most prevalent OMP in the matrix, and its absence altered biofilm architecture by increasing VPS production. Single-cell force spectroscopy revealed that proteins critical for biofilm formation, OmpU, the matrix proteins RbmA, RbmC, Bap1, and VPS contribute to cell-surface adhesion forces at differing efficiency, with VPS showing the highest efficiency whereas Bap1 showing the lowest efficiency. Our findings provide new insights into the molecular mechanisms underlying biofilm matrix assembly in V. cholerae, which may provide new opportunities to develop inhibitors that specifically alter biofilm matrix properties and, thus, affect either the environmental survival or pathogenesis of V. cholerae.IMPORTANCECholera remains a major public health concern. Vibrio cholerae, the causative agent of cholera, forms biofilms, which are critical for its transmission, infectivity, and environmental persistence. While we know that the V. cholerae biofilm matrix contains exopolysaccharide, matrix proteins, and extracellular DNA, we do not have a comprehensive understanding of the majority of biofilm matrix components. Here, we discover outer membrane vesicles (OMVs) within the biofilm matrix of V. cholerae. Proteomic analysis of the matrix and matrix-associated OMVs showed that OMVs carry key matrix proteins and Vibrio polysaccharide (VPS) to help build biofilms. We also characterize the role of the highly abundant outer membrane protein OmpU in biofilm formation and show that it impacts biofilm architecture in a VPS-dependent manner. Understanding V. cholerae biofilm formation is important for developing a better prevention and treatment strategy framework.
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Affiliation(s)
- Anna Potapova
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - William Garvey
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - Peter Dahl
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Shuaiqi Guo
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Yunjie Chang
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Carmen Schwechheimer
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - Michael A. Trebino
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - Kyle A. Floyd
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - Brett S. Phinney
- Proteomics Core Facility, UC Davis Genome Center, University of California-Davis, Davis, California, USA
| | - Jun Liu
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Nikhil S. Malvankar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Fitnat H. Yildiz
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
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Feng Y, Sun JW, Shi WW, Duan JL, Sun XD, Feng LJ, Wang Q, Gan YD, Yuan XZ. Microplastics exhibit accumulation and horizontal transfer of antibiotic resistance genes. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 336:117632. [PMID: 36921474 DOI: 10.1016/j.jenvman.2023.117632] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/02/2023] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
Although the fates of microplastics (0.1-5 mm) in marine environments and freshwater are increasingly studied, little is known about their vector effect in wastewater treatment plants (WWTPs). Previous studies have evaluated the accumulation of antibiotic resistance genes (ARGs) on microplastics, but there is no direct evidence for the selection and horizontal transfer of ARGs on different microplastics in WWTPs. Here, we show biofilm formation as well as bacterial community and ARGs in these biofilms grown on four kinds of microplastics via incubation in the aerobic and anaerobic tanks of a WWTP. Microplastics showed differential capacities for bacteria and ARGs enrichment, differing from those of the culture environment. Furthermore, ARGs in microplastic biofilms were horizontally transferred at frequencies higher than those in water samples in both tanks. Therefore, microplastics in WWTPs can act as substrates for horizontal transfer of ARGs, potentially causing a great harm to the ecological environment and adversely affecting human health.
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Affiliation(s)
- Yue Feng
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, PR China; College of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao, Shandong 266590, PR China
| | - Jia-Wen Sun
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, PR China
| | - Wei-Wei Shi
- Center for Soil Pollution Control of Shandong, Jinan, Shandong 250012, PR China
| | - Jian-Lu Duan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, PR China
| | - Xiao-Dong Sun
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, PR China
| | - Li-Juan Feng
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, PR China
| | - Qian Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, PR China
| | - Yu-Dong Gan
- Department of Orthopedics, Qilu Hospital of Shandong University, Jinan, Shandong 250063, PR China.
| | - Xian-Zheng Yuan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, PR China.
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Globally Vibrio cholera antibiotics resistance to RNA and DNA effective antibiotics: A systematic review and meta-analysis. Microb Pathog 2022; 172:105514. [DOI: 10.1016/j.micpath.2022.105514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 11/19/2022]
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Yuan XH, Li YM, Vaziri AZ, Kaviar VH, Jin Y, Jin Y, Maleki A, Omidi N, Kouhsari E. Global status of antimicrobial resistance among environmental isolates of Vibrio cholerae O1/O139: a systematic review and meta-analysis. Antimicrob Resist Infect Control 2022; 11:62. [PMID: 35468830 PMCID: PMC9036709 DOI: 10.1186/s13756-022-01100-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 04/11/2022] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Vibrio cholerae O1/O139 were the predominant circulating serogroups exhibiting multi-drug resistance (MDR) during the cholera outbreak which led to cholera treatment failures. OBJECTIVE This meta-analysis aimed to evaluate the weighted pooled resistance (WPR) rates in V. cholerae O1/O139 isolates obtained from environmental samples. METHODS We systematically searched the articles in PubMed, Scopus, and Embase (until January 2020). Subgroup analyses were then employed by publication year, geographic areas, and the quality of studies. Statistical analyses were conducted using STATA software (ver. 14.0). RESULTS A total of 20 studies investigating 648 environmental V. cholerae O1/O139 isolates were analysed. The majority of the studies were originated from Asia (n = 9). In addition, a large number of studies (n = 15 i.e. 71.4%) included in the meta-analysis revealed the resistance to cotrimoxazole and ciprofloxacin. The WPR rates were as follows: cotrimoxazole 59%, erythromycin 28%, tetracycline 14%, doxycycline 5%, and ciprofloxacin 0%. There was increased resistance to nalidixic acid, cotrimoxazole, furazolidone, and tetracycline while a decreased resistance to amoxicillin, ciprofloxacin, erythromycin, chloramphenicol, ampicillin, streptomycin, and ceftriaxone was observed during the years 2000-2020. A significant decrease in the doxycycline and ciprofloxacin-resistance rates in V. cholerae O1/O139 isolates was reported over the years 2011-2020 which represents a decrease in 2001-2010 (p < 0.05). CONCLUSIONS Fluoroquinolones, gentamicin, ceftriaxone, doxycycline, kanamycin, and cefotaxime showed the highest effectiveness and the lowest resistance rate. However, the main interest is the rise of antimicrobial resistance in V. cholerae strains especially in low-income countries or endemic areas, and therefore, continuous surveillance, careful appropriate AST, and limitation on improper antibiotic usage are crucial.
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Affiliation(s)
- Xin-Hui Yuan
- The First Hospital of Lanzhou University, Lanzhou, 730000, China
- Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, 210008, China
| | - Yu-Mei Li
- The First Hospital of Lanzhou University, Lanzhou, 730000, China
| | - Ali Zaman Vaziri
- Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Science, Islamic Azad University, Tehran, Iran
| | - Vahab Hassan Kaviar
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Yang Jin
- Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, 210008, China
| | - Yu Jin
- Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, 210008, China.
| | - Abbas Maleki
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Nazanin Omidi
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Ebrahim Kouhsari
- Laboratory Sciences Research Center, Faculty of Paramedical Sciences, Golestan University of Medical Sciences, Gorgan, Iran.
- Department of Laboratory Sciences, Faculty of Paramedicine, Golestan University of Medical Sciences, Gorgan, Iran.
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Metcalf R, Oliver DM, Moresco V, Quilliam RS. Quantifying the importance of plastic pollution for the dissemination of human pathogens: The challenges of choosing an appropriate 'control' material. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 810:152292. [PMID: 34896491 DOI: 10.1016/j.scitotenv.2021.152292] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/26/2021] [Accepted: 12/05/2021] [Indexed: 06/14/2023]
Abstract
Discarded plastic wastes in the environment are serious challenges for sustainable waste management and for the delivery of environmental and public health. Plastics in the environment become rapidly colonised by microbial biofilm, and importantly this so-called 'plastisphere' can also support, or even enrich human pathogens. The plastisphere provides a protective environment and could facilitate the increased survival, transport and dissemination of human pathogens and thus increase the likelihood of pathogens coming into contact with humans, e.g., through direct exposure at beaches or bathing waters. However, much of our understanding about the relative risks associated with human pathogens colonising environmental plastic pollution has been inferred from taxonomic identification of pathogens in the plastisphere, or laboratory experiments on the relative behaviour of plastics colonised by human pathogens. There is, therefore, a pressing need to understand whether plastics play a greater role in promoting the survival and dispersal of human pathogens within the environment compared to other substrates (either natural materials or other pollutants). In this paper, we consider all published studies that have detected human pathogenic bacteria on the surfaces of environmental plastic pollution and critically discuss the challenges of selecting an appropriate control material for plastisphere experiments. Whilst it is clear there is no 'perfect' control material for all plastisphere studies, understanding the context-specific role plastics play compared to other substrates for transferring human pathogens through the environment is important for quantifying the potential risk that colonised plastic pollution may have for environmental and public health.
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Affiliation(s)
- Rebecca Metcalf
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK.
| | - David M Oliver
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Vanessa Moresco
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Richard S Quilliam
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
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6
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Chakrabortty T, Roy Chowdhury S, Ghosh B, Sen U. Crystal Structure of VpsR Revealed Novel Dimeric Architecture and c-di-GMP Binding Site: Mechanistic Implications in Oligomerization, ATPase Activity and DNA Binding. J Mol Biol 2021; 434:167354. [PMID: 34774564 DOI: 10.1016/j.jmb.2021.167354] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/04/2021] [Accepted: 11/04/2021] [Indexed: 01/09/2023]
Abstract
VpsR, the master regulator of biofilm formation in Vibrio cholerae, is an atypical NtrC1 type bEBP lacking residues essential for σ54-RNAP binding and REC domain phosphorylation. Moreover, transcription from PvpsL, a promoter of biofilm biosynthesis, has been documented in presence of σ70-RNAP/VpsR/c-di-GMP complex. It was proposed that c-di-GMP and VpsR together form an active transcription complex with σ70-RNAP. However, the impact of c-di-GMP imparted on VpsR that leads to transcription activation with σ70-RNAP remained elusive, largely due to the lack of the structure of VpsR and knowledge about c-di-GMP:VpsR interactions. In this direction we have solved the crystal structure of VpsRRA, containing REC and AAA+ domains, in apo, AMPPNP/GMPPNP and c-di-GMP bound states. Structures of VpsRRA unveiled distinctive REC domain orientation that leads to a novel dimeric association and noncanonical ATP/GTP binding. Moreover, we have demonstrated that at physiological pH VpsR remains as monomer having no ATPase activity but c-di-GMP imparted cooperativity to convert it to dimer with potent activity. Crystal structure of c-di-GMP:VpsRRA complex reveals that c-di-GMP binds near the C-terminal end of AAA+ domain. Trp quenching studies on VpsRR, VpsRA, VpsRRA, VpsRAD with c-di-GMP additionally demonstrated that c-di-GMP could potentially bind VpsRD. We propose that c-di-GMP mediated tethering of VpsRD with VpsRA could likely favor generating the specific protein-DNA architecture for transcription activation.
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Affiliation(s)
- Tulika Chakrabortty
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhan Nagar, Kolkata 700064, India. https://twitter.com/@TulikaC02382598
| | - Sanghati Roy Chowdhury
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhan Nagar, Kolkata 700064, India
| | - Biplab Ghosh
- High Pressure & Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Udayaditya Sen
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhan Nagar, Kolkata 700064, India.
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7
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Contributions of Escherichia coli and Its Motility to the Formation of Dual-Species Biofilms with Vibrio cholerae. Appl Environ Microbiol 2021; 87:e0093821. [PMID: 34260307 DOI: 10.1128/aem.00938-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biofilm formation is important in both the environmental and intestinal phases of the Vibrio cholerae life cycle. Nevertheless, most studies of V. cholerae biofilm formation focus on monospecies cultures, whereas nearly all biofilm communities found in nature consist of a variety of microorganisms. Multispecies biofilms formed between V. cholerae and other bacteria in the environment and the interactions that exist between these species are still poorly understood. In this study, the influence of Escherichia coli on the biofilm formation of V. cholerae was studied in the context of both in vitro coculture and in vivo coinfection. To understand the underlying synergistic mechanisms between these two species and to investigate the role of E. coli in V. cholerae biofilm formation, different pathotypes of E. coli and corresponding deletion mutants lacking genes that influence flagellar motility, curli fibers, or type I pili were cocultured with V. cholerae. Our findings demonstrate that the presence of commensal E. coli increases biofilm formation at the air-liquid interface in vitro and the generation of biofilm-like multicellular clumps in mouse feces. Examination of laboratory E. coli flagellar-motility ΔfliC and ΔmotA mutants in dual-species biofilm formation suggests that flagellar motility plays an important role in the synergistic interaction and coaggregation formation between V. cholerae and E. coli. This study facilitates a better understanding of how V. cholerae resides in harsh environments and colonizes the intestine. IMPORTANCE Biofilms play an important role in the V. cholerae life cycle. Until now, only monospecies biofilm formation of V. cholerae has been well studied. However, in nature, bacteria live in complex microbial communities, where biofilm is mostly composed of multiple microbial species that interact to cooperate with or compete against each other. Uncovering how V. cholerae forms multispecies biofilms is critical for furthering our understanding of how V. cholerae survives in the environment and transitions to infecting the human host. In this work, the dual-species biofilm containing V. cholerae and Escherichia coli was investigated. We demonstrate that the presence of commensal E. coli increased overall biofilm formation. Furthermore, we demonstrate that the motility of E. coli flagella is important for V. cholerae and E. coli to form coaggregation clumps in a dual-species biofilm. These results shed light on a new mechanism for understanding the survival and pathogenesis of V. cholerae.
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Aavani F, Biazar E, Heshmatipour Z, Arabameri N, Kamalvand M, Nazbar A. Applications of bacteria and their derived biomaterials for repair and tissue regeneration. Regen Med 2021; 16:581-605. [PMID: 34030458 DOI: 10.2217/rme-2020-0116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Microorganisms such as bacteria and their derived biopolymers can be used in biomaterials and tissue regeneration. Various methods have been applied to regenerate damaged tissues, but using probiotics and biomaterials derived from bacteria with improved economic-production efficiency and highly applicable properties can be a new solution in tissue regeneration. Bacteria can synthesize numerous types of biopolymers. These biopolymers possess many desirable properties such as biocompatibility and biodegradability, making them good candidates for tissue regeneration. Here, we reviewed different types of bacterial-derived biopolymers and highlight their applications for tissue regeneration.
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Affiliation(s)
- Farzaneh Aavani
- Biomedical Engineering Faculty, Amirkabir University of Technology (Tehran Polytechnic), 15916-34311 Tehran, Iran
| | - Esmaeil Biazar
- Department of Biomedical Engineering, Tissue Engineering Group, Tonekabon Branch, Islamic Azad University, 46841-61167 Tonekabon, Iran
| | - Zoheir Heshmatipour
- Department of Microbiology, Tonekabon Branch, Islamic Azad University, 46841-61167 Tonekabon, Iran
| | - Nasibeh Arabameri
- Department of Microbiology, Tonekabon Branch, Islamic Azad University, 46841-61167 Tonekabon, Iran
| | - Mahshad Kamalvand
- Department of Biomedical Engineering, Tissue Engineering Group, Tonekabon Branch, Islamic Azad University, 46841-61167 Tonekabon, Iran
| | - Abolfazl Nazbar
- National Cell Bank, Pasteur Institute of Iran, 13169-43551 Tehran, Iran
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9
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del Peso Santos T, Alvarez L, Sit B, Irazoki O, Blake J, Warner BR, Warr AR, Bala A, Benes V, Waldor MK, Fredrick K, Cava F. BipA exerts temperature-dependent translational control of biofilm-associated colony morphology in Vibrio cholerae. eLife 2021; 10:e60607. [PMID: 33588990 PMCID: PMC7886329 DOI: 10.7554/elife.60607] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 02/03/2021] [Indexed: 12/18/2022] Open
Abstract
Adaptation to shifting temperatures is crucial for the survival of the bacterial pathogen Vibrio cholerae. Here, we show that colony rugosity, a biofilm-associated phenotype, is regulated by temperature in V. cholerae strains that naturally lack the master biofilm transcriptional regulator HapR. Using transposon-insertion mutagenesis, we found the V. cholerae ortholog of BipA, a conserved ribosome-associated GTPase, is critical for this temperature-dependent phenomenon. Proteomic analyses revealed that loss of BipA alters the synthesis of >300 proteins in V. cholerae at 22°C, increasing the production of biofilm-related proteins including the key transcriptional activators VpsR and VpsT, as well as proteins important for diverse cellular processes. At low temperatures, BipA protein levels increase and are required for optimal ribosome assembly in V. cholerae, suggesting that control of BipA abundance is a mechanism by which bacteria can remodel their proteomes. Our study reveals a remarkable new facet of V. cholerae's complex biofilm regulatory network.
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Affiliation(s)
- Teresa del Peso Santos
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Laura Alvarez
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Brandon Sit
- Howard Hughes Medical Institute, Brigham and Women's Hospital Division of Infectious Diseases and Harvard Medical School Department of Microbiology and ImmunobiologyBoston, MAUnited States
| | - Oihane Irazoki
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Jonathon Blake
- Genomics Core Facility, European Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Benjamin R Warner
- Department of Microbiology, The Ohio State UniversityColumbus, OHUnited States
- Center for RNA Biology, The Ohio State UniversityColumbus, OHUnited States
| | - Alyson R Warr
- Howard Hughes Medical Institute, Brigham and Women's Hospital Division of Infectious Diseases and Harvard Medical School Department of Microbiology and ImmunobiologyBoston, MAUnited States
| | - Anju Bala
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Vladimir Benes
- Genomics Core Facility, European Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Matthew K Waldor
- Howard Hughes Medical Institute, Brigham and Women's Hospital Division of Infectious Diseases and Harvard Medical School Department of Microbiology and ImmunobiologyBoston, MAUnited States
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State UniversityColumbus, OHUnited States
- Center for RNA Biology, The Ohio State UniversityColumbus, OHUnited States
| | - Felipe Cava
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
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10
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Hsieh ML, Waters CM, Hinton DM. VpsR Directly Activates Transcription of Multiple Biofilm Genes in Vibrio cholerae. J Bacteriol 2020; 202:e00234-20. [PMID: 32661076 PMCID: PMC7925080 DOI: 10.1128/jb.00234-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 06/25/2020] [Indexed: 01/05/2023] Open
Abstract
Vibrio cholerae biofilm biogenesis, which is important for survival, dissemination, and persistence, requires multiple genes in the Vibrio polysaccharides (vps) operons I and II as well as the cluster of ribomatrix (rbm) genes. Transcriptional control of these genes is a complex process that requires several activators/repressors and the ubiquitous signaling molecule, cyclic di-GMP (c-di-GMP). Previously, we demonstrated that VpsR directly activates RNA polymerase containing σ70 (σ70-RNAP) at the vpsL promoter (P vpsL ), which precedes the vps-II operon, in a c-di-GMP-dependent manner by stimulating formation of the transcriptionally active, open complex. Using in vitro transcription, electrophoretic mobility shift assays, and DNase I footprinting, we show here that VpsR also directly activates σ70-RNAP transcription from other promoters within the biofilm formation cluster, including P vpsU , at the beginning of the vps-I operon, P rbmA , at the start of the rbm cluster, and P rbmF , which lies upstream of the divergent rbmF and rbmE genes. In this capacity, we find that VpsR is able to behave both as a class II activator, which functions immediately adjacent/overlapping the core promoter sequence (P vpsL and P vpsU ), and as a class I activator, which functions farther upstream (P rbmA and P rbmF ). Because these promoters vary in VpsR-DNA binding affinity in the absence and presence of c-di-GMP, we speculate that VpsR's mechanism of activation is dependent on both the concentration of VpsR and the level of c-di-GMP to increase transcription, resulting in finely tuned regulation.IMPORTANCEVibrio cholerae, the bacterial pathogen that is responsible for the disease cholera, uses biofilms to aid in survival, dissemination, and persistence. VpsR, which directly senses the second messenger c-di-GMP, is a major regulator of this process. Together with c-di-GMP, VpsR directly activates transcription by RNA polymerase containing σ70 from the vpsL biofilm biogenesis promoter. Using biochemical methods, we demonstrate for the first time that VpsR/c-di-GMP directly activates σ70-RNA polymerase at the first genes of the vps and ribomatrix operons. In this regard, it functions as either a class I or class II activator. Our results broaden the mechanism of c-di-GMP-dependent transcription activation and the specific role of VpsR in biofilm formation.
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Affiliation(s)
- Meng-Lun Hsieh
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
- Gene Expression and Regulation Section, Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Christopher M Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Deborah M Hinton
- Gene Expression and Regulation Section, Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
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11
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Bueno E, Pinedo V, Cava F. Adaptation of Vibrio cholerae to Hypoxic Environments. Front Microbiol 2020; 11:739. [PMID: 32425907 PMCID: PMC7212424 DOI: 10.3389/fmicb.2020.00739] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/30/2020] [Indexed: 01/02/2023] Open
Abstract
Bacteria can colonize virtually any environment on Earth due to their remarkable capacity to detect and respond quickly and adequately to environmental stressors. Vibrio cholerae is a cosmopolitan bacterium that inhabits a vast range of environments. The V. cholerae life cycle comprises diverse environmental and infective stages. The bacterium is found in aquatic ecosystems both under free-living conditions or associated with a wide range of aquatic organisms, and some strains are also capable of causing epidemics in humans. In order to adapt between environments, V. cholerae possesses a versatile metabolism characterized by the rapid cross-regulation of energy-producing pathways. Low oxygen concentration is a key environmental factor that governs V. cholerae physiology. This article reviews the metabolic plasticity that enables V. cholerae to thrive on low oxygen concentrations and its role in environmental and host adaptation.
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Affiliation(s)
- Emilio Bueno
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | | | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
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12
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Kaus K, Biester A, Chupp E, Lu J, Visudharomn C, Olson R. The 1.9 Å crystal structure of the extracellular matrix protein Bap1 from Vibrio cholerae provides insights into bacterial biofilm adhesion. J Biol Chem 2019; 294:14499-14511. [PMID: 31439670 DOI: 10.1074/jbc.ra119.008335] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/16/2019] [Indexed: 01/09/2023] Open
Abstract
Growth of the cholera bacterium Vibrio cholerae in a biofilm community contributes to both its pathogenicity and survival in aquatic environmental niches. The major components of V. cholerae biofilms include Vibrio polysaccharide (VPS) and the extracellular matrix proteins RbmA, RbmC, and Bap1. To further elucidate the previously observed overlapping roles of Bap1 and RbmC in biofilm architecture and surface attachment, here we investigated the structural and functional properties of Bap1. Soluble expression of Bap1 was possible only after the removal of an internal 57-amino-acid-long hydrophobic insertion sequence. The crystal structure of Bap1 at 1.9 Å resolution revealed a two-domain assembly made up of an eight-bladed β-propeller interrupted by a β-prism domain. The structure also revealed metal-binding sites within canonical calcium blade motifs, which appear to have structural rather than functional roles. Contrary to results previously observed with RbmC, the Bap1 β-prism domain did not exhibit affinity for complex N-glycans, suggesting an altered role of this domain in biofilm-surface adhesion. Native polyacrylamide gel shift analysis did suggest that Bap1 exhibits lectin activity with a preference for anionic or linear polysaccharides. Our results suggest a model for V. cholerae biofilms in which Bap1 and RbmC play dominant but differing adhesive roles in biofilms, allowing bacterial attachment to diverse environmental or host surfaces.
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Affiliation(s)
- Katherine Kaus
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut 06459
| | - Alison Biester
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut 06459
| | - Ethan Chupp
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut 06459
| | - Jianyi Lu
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut 06459
| | - Charlie Visudharomn
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut 06459
| | - Rich Olson
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut 06459
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Kesy K, Oberbeckmann S, Kreikemeyer B, Labrenz M. Spatial Environmental Heterogeneity Determines Young Biofilm Assemblages on Microplastics in Baltic Sea Mesocosms. Front Microbiol 2019; 10:1665. [PMID: 31447791 PMCID: PMC6696623 DOI: 10.3389/fmicb.2019.01665] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 07/04/2019] [Indexed: 11/13/2022] Open
Abstract
Microplastics in aquatic environments provide novel habitats for surface-colonizing microorganisms. Given the continuing debate on whether substrate-specific properties or environmental factors prevail in shaping biofilm assemblages on microplastics, we examined the influence of substrate vs. spatial factors in the development of bacterial assemblages on polyethylene (PE), polystyrene (PS), wood, and seston and in the free-living fraction. Further, the selective colonization of microplastics by potential pathogens was investigated because among the bacterial species found in microplastic-associated biofilms are potentially pathogenic Vibrio spp. Due to their persistence and great dispersal potential, microplastics could act as vectors for these potential pathogens and for biofilm assemblages in general. Incubation experiments with these substrates were conducted for 7 days during a summer cruise along the eastern Baltic Sea coastline in waters covering a salinity gradient of 4.5-9 PSU. Bacterial assemblages were analyzed using 16S rRNA-gene amplicon sequencing, distance-based redundancy analyses, and the linear discriminant analysis effect size method to identify taxa that were significantly more abundant on the plastics. The results showed that the sample type was the most important factor structuring bacterial assemblages overall. Surface properties were less significant in differentiating attached biofilms on PE, PS, and wood; instead, environmental factors, mainly salinity, prevailed. A potential role for inorganic-nutrient limitations in surface-specific attachment was identified as well. Alphaproteobacteria (Sphingomonadaceae, Devosiaceae, and Rhodobacteraceae) and Gammaproteobacteria (Alteromonadaceae and Pseudomonas) were distinctive for the PE- and PS-associated biofilms. Vibrio was more abundant on the PE and PS biofilms than on seston, but its abundances were highest on wood and positively correlated with salinity. These results corroborate earlier findings that microplastics constitute a habitat for biofilm-forming microorganisms distinct from seston, but less from wood. In contrast to earlier reports of low Vibrio numbers on microplastics, these results also suggest that vibrios are early colonizers of surfaces in general. Spatial as well as temporal dynamics should therefore be considered when assessing the potential of microplastics to serve as vectors for bacterial assemblages and putative pathogens, as these parameters are major drivers of biofilm diversity.
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Affiliation(s)
- Katharina Kesy
- Biological Oceanography, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany
| | - Sonja Oberbeckmann
- Biological Oceanography, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany
| | - Bernd Kreikemeyer
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Rostock, Rostock, Germany
| | - Matthias Labrenz
- Biological Oceanography, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany
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14
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Alolga RN, Chávez León MASC, Osei-Adjei G, Onoja V. GC-MS-based metabolomics, antibacterial and anti-inflammatory investigations to characterize the quality of essential oil obtained from dried Xylopia aethiopica fruits from Ghana and Nigeria. J Pharm Pharmacol 2019; 71:1544-1552. [DOI: 10.1111/jphp.13150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 07/06/2019] [Indexed: 01/08/2023]
Abstract
Abstract
Objectives
This study sought to determine the quality of essential oil from Xylopia aethiopica fruits of different geographical origins using GC-MS-based metabolomics, bacterial quorum sensing and anti-inflammation assessment.
Methods
Essential oil was obtained from eight batches of X. aethiopica fruits from Ghana and Nigeria by hydrodistillation, characterized using gas chromatography–mass spectrometry and differences therein found using metabolomics. The respective antibacterial activity of the oils was tested against four bacterial strains: two Gram-positive strains, Staphylococcus aureus (ATCC 25923) and Bacillus licheniformis (ATCC12759), and two Gram-negative strains, Escherichia coli (ATCC25922) and Klebsiella pneumoniae (ATCC 13883). Anti-inflammation was tested using RAW 264.7 macrophage cells.
Key findings
The outcome of the study revealed that the oil of the Ghana-sourced samples exhibited superior antibacterial, cytotoxic and anti-inflammatory effects than those from Nigeria. This could be attributed to the higher levels of the bioactive compounds present in those samples. This distinction between the samples from the two countries was clearly established using the metabolomics approach, and 14 differential metabolites were found to be potential chemical markers.
Conclusions
The study lends credence to the traditional uses of the essential oil of X. aethiopica as an antimicrobial and anti-inflammatory agent.
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Affiliation(s)
- Raphael N Alolga
- State Key Laboratory of Natural Medicines, Department of Pharmacognosy, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - María A S C Chávez León
- State Key Laboratory of Natural Medicines, Department of Pharmacognosy, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | | | - Vitus Onoja
- Department of Pharmaceutics and Pharmaceutical Technology, University of Jos, Jos, Nigeria
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15
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Hsieh ML, Hinton DM, Waters CM. VpsR and cyclic di-GMP together drive transcription initiation to activate biofilm formation in Vibrio cholerae. Nucleic Acids Res 2019; 46:8876-8887. [PMID: 30007313 PMCID: PMC6158489 DOI: 10.1093/nar/gky606] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/09/2018] [Indexed: 11/14/2022] Open
Abstract
The small molecule cyclic di-GMP (c-di-GMP) is known to affect bacterial gene expression in myriad ways. In Vibrio cholerae in vivo, the presence of c-di-GMP together with the response regulator VpsR results in transcription from PvpsL, a promoter of biofilm biosynthesis genes. VpsR shares homology with enhancer binding proteins that activate σ54-RNA polymerase (RNAP), but it lacks conserved residues needed to bind to σ54-RNAP and to hydrolyze adenosine triphosphate, and PvpsL transcription does not require σ54 in vivo. Consequently, the mechanism of this activation has not been clear. Using an in vitro transcription system, we demonstrate activation of PvspL in the presence of VpsR, c-di-GMP and σ70-RNAP. c-di-GMP does not significantly change the affinity of VpsR for PvpsL DNA or the DNase I footprint of VpsR on the DNA, and it is not required for VpsR to dimerize. However, DNase I and KMnO4 footprints reveal that the σ70-RNAP/VpsR/c-di-GMP complex on PvpsL adopts a different conformation from that formed by σ70-RNAP alone, with c-di-GMP or with VpsR. Our results suggest that c-di-GMP is required for VpsR to generate the specific protein–DNA architecture needed for activated transcription, a previously unrecognized role for c-di-GMP in gene expression.
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Affiliation(s)
- Meng-Lun Hsieh
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.,Gene Expression and Regulation Section, Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Deborah M Hinton
- Gene Expression and Regulation Section, Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christopher M Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
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16
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Cai S, Cheng H, Pang H, Lu Y, Jian J. Role of the toxR Gene from Fish Pathogen Vibiro alginolyticus in the Physiology and Virulence. Indian J Microbiol 2017; 57:477-484. [PMID: 29151649 DOI: 10.1007/s12088-017-0685-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 10/21/2017] [Indexed: 12/19/2022] Open
Abstract
A mutant strain of Vibiro alginolyticus with an in-frame deletion of the toxR gene was constructed to reveal the role of ToxR in the physiology and virulence of V. alginolyticus. The statistical analysis showed no significant difference in the growth ability, swarming motility, activity of extracellular protease and the virulence by injection (the value of LD50) between the wild-type and the toxR mutant. However, the deletion of toxR could decrease the level of biofilm formation. The comparative proteomic analysis demonstrated the deletion mutation of toxR could up-regulate the expression of glutamine synthetase and levansucrase, and down-regulate the expression of 10 proteins such as OmpU, DnaK, etc. These results suggest that ToxR may be involved in the early stages of infection by influencing colonization of the bacteria on the surface of the intestine through enhancing the biofilm information of V. alginolyticus via modulating the expression of glutamine synthetize, levansucrase and OmpU.
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Affiliation(s)
- Shuanghu Cai
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals and Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Haiyan Cheng
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals and Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Huanying Pang
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals and Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Yishan Lu
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals and Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Jichan Jian
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals and Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China
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17
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The Two-Component Signal Transduction System VxrAB Positively Regulates Vibrio cholerae Biofilm Formation. J Bacteriol 2017; 199:JB.00139-17. [PMID: 28607158 DOI: 10.1128/jb.00139-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/05/2017] [Indexed: 11/20/2022] Open
Abstract
Two-component signal transduction systems (TCSs), typically composed of a sensor histidine kinase (HK) and a response regulator (RR), are the primary mechanism by which pathogenic bacteria sense and respond to extracellular signals. The pathogenic bacterium Vibrio cholerae is no exception and harbors 52 RR genes. Using in-frame deletion mutants of each RR gene, we performed a systematic analysis of their role in V. cholerae biofilm formation. We determined that 7 RRs impacted the expression of an essential biofilm gene and found that the recently characterized RR, VxrB, regulates the expression of key structural and regulatory biofilm genes in V. choleraevxrB is part of a 5-gene operon, which contains the cognate HK vxrA and three genes of unknown function. Strains carrying ΔvxrA and ΔvxrB mutations are deficient in biofilm formation, while the ΔvxrC mutation enhances biofilm formation. The overexpression of VxrB led to a decrease in motility. We also observed a small but reproducible effect of the absence of VxrB on the levels of cyclic di-GMP (c-di-GMP). Our work reveals a new function for the Vxr TCS as a regulator of biofilm formation and suggests that this regulation may act through key biofilm regulators and the modulation of cellular c-di-GMP levels.IMPORTANCE Biofilms play an important role in the Vibrio cholerae life cycle, providing protection from environmental stresses and contributing to the transmission of V. cholerae to the human host. V. cholerae can utilize two-component systems (TCS), composed of a histidine kinase (HK) and a response regulator (RR), to regulate biofilm formation in response to external cues. We performed a systematic analysis of V. cholerae RRs and identified a new regulator of biofilm formation, VxrB. We demonstrated that the VxrAB TCS is essential for robust biofilm formation and that this system may regulate biofilm formation via its regulation of key biofilm regulators and cyclic di-GMP levels. This research furthers our understanding of the role that TCSs play in the regulation of V. cholerae biofilm formation.
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Abstract
Infectious diseases kill nearly 9 million people annually. Bacterial pathogens are responsible for a large proportion of these diseases, and the bacterial agents of pneumonia, diarrhea, and tuberculosis are leading causes of death and disability worldwide. Increasingly, the crucial role of nonhost environments in the life cycle of bacterial pathogens is being recognized. Heightened scrutiny has been given to the biological processes impacting pathogen dissemination and survival in the natural environment, because these processes are essential for the transmission of pathogenic bacteria to new hosts. This chapter focuses on the model environmental pathogen Vibrio cholerae to describe recent advances in our understanding of how pathogens survive between hosts and to highlight the processes necessary to support the cycle of environmental survival, transmission, and dissemination. We describe the physiological and molecular responses of V. cholerae to changing environmental conditions, focusing on its survival in aquatic reservoirs between hosts and its entry into and exit from human hosts.
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19
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Xu M, Wang YZ, Yang XA, Jiang T, Xie W. Structural studies of the periplasmic portion of the diguanylate cyclase CdgH from Vibrio cholerae. Sci Rep 2017; 7:1861. [PMID: 28500346 PMCID: PMC5431781 DOI: 10.1038/s41598-017-01989-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 04/06/2017] [Indexed: 01/07/2023] Open
Abstract
Cyclic diguanylate monophosphate (c-di-GMP) is a second messenger involved in bacterial signal transduction and produced by diguanylate cyclases (DGCs) generally containing highly variable periplasmic signal-recognition domains. CdgH is a DGC enzyme that regulates rugosity associated phenotypes in Vibrio cholerae. CdgH has two N-terminal tandem periplasmic substrate-binding (PBPb) domains for its signal recognition; however, the role of the tandem PBPb domains remains unclear. Here, we reported the crystal structure of the periplasmic portion of CdgH, which indicated that both tandem PBPb domains consist of typical interlobe ligand-binding architecture. Unexpectedly, the PBPb-I domain binds an L-arginine which apparently has been co-purified from the E. coli expression system, whereas the PBPb-II domain is in an unliganded open state. Structural comparison with other amino acid-binding proteins indicated that despite similar ligand-binding pockets, the PBPb-I domain possesses two ligand-binding residues (E122 and Y148) not conserved in homologs and involved in hydrophilic and hydrophobic interactions with L-arginine. Isothermal titration calorimetry indicated that the PBPb-I is primarily an L-arginine/L-lysine/L-ornithine-binding domain, whereas the PBPb-II domain exhibits a preference for L-glutamine and L-histidine. Remarkably, we found that the periplasmic portion of CdgH forms a stable dimer in solution and L-arginine binding would cause conformational changes of the dimer.
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Affiliation(s)
- Min Xu
- 0000 0004 1792 5640grid.418856.6National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yi-Zhi Wang
- 0000 0004 1792 5640grid.418856.6National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,0000 0004 1797 8419grid.410726.6University of Chinese Academy of Sciences, Beijing, China
| | - Xiu-An Yang
- 0000 0004 1792 5640grid.418856.6National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Tao Jiang
- 0000 0004 1792 5640grid.418856.6National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,0000 0004 1797 8419grid.410726.6University of Chinese Academy of Sciences, Beijing, China
| | - Wei Xie
- 0000 0004 1761 2484grid.33763.32School of Life Sciences, Tianjin University, Tianjin, China
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20
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Khandeparker L, Eswaran R, Gardade L, Kuchi N, Mapari K, Naik SD, Anil AC. Elucidation of the tidal influence on bacterial populations in a monsoon influenced estuary through simultaneous observations. ENVIRONMENTAL MONITORING AND ASSESSMENT 2017; 189:41. [PMID: 28035613 DOI: 10.1007/s10661-016-5687-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Abstract
The influence of tides on bacterial populations in a monsoon influenced tropical estuary was assessed through fine resolution sampling (1 to 3 h) during spring and neap tides from mouth to the freshwater end at four stations during pre-monsoon, monsoon and post-monsoon seasons. Higher abundance of total bacterial count (TBC) in surface water near the river mouth, compared to the upstream, during pre-monsoon was followed by an opposite scenario during the monsoon When seasonally compared, it was during the post-monsoon season when TBC in surface water was highest, with simultaneous decrease in their count in the river sediment. The total viable bacterial count (TVC) was influenced by the depth-wise stratification of salinity, which varied with tidal fluctuation, usually high and low during the neap and spring tides respectively. The abundance of both the autochthonous Vibrio spp. and allochthonous coliform bacteria was influenced by the concentrations of dissolved nutrients and suspended particulate matter (SPM). It is concluded that depending on the interplay of riverine discharge and tidal amplitude, sediment re-suspension mediated increase in SPM significantly regulates bacteria populations in the estuarine water, urging the need of systematic regular monitoring for better prediction of related hazards, including those associated with the rise in pathogenic Vibrio spp. in the changing climatic scenarios.
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Affiliation(s)
| | - Ranjith Eswaran
- CSIR-National Institute of Oceanography, Dona Paula, Goa, India
| | - Laxman Gardade
- CSIR-National Institute of Oceanography, Dona Paula, Goa, India
| | - Nishanth Kuchi
- CSIR-National Institute of Oceanography, Dona Paula, Goa, India
| | - Kaushal Mapari
- CSIR-National Institute of Oceanography, Dona Paula, Goa, India
| | - Sneha D Naik
- CSIR-National Institute of Oceanography, Dona Paula, Goa, India
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21
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Sengupta C, Mukherjee O, Chowdhury R. Adherence to Intestinal Cells Promotes Biofilm Formation in Vibrio cholerae. J Infect Dis 2016; 214:1571-1578. [PMID: 27638940 DOI: 10.1093/infdis/jiw435] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 09/08/2016] [Indexed: 02/04/2023] Open
Abstract
Vibrio cholerae, the etiological agent of cholera, is known to form biofilms to persist in the environment. It is demonstrated here that even during infection, biofilm genes are upregulated, and microscopic observation indicated that biofilm formation is initiated almost immediately after adherence of V. cholerae to intestinal cells. About 7-fold upregulation of the biofilm regulatory gene vpsT was observed within 30 minutes of adherence of V. cholerae to the intestinal cell line INT 407, and a massive induction of about 700-fold was observed in rabbit ileal loops. The upregulation was observed in the classical and El Tor biotype strains of serogroup O1 that is most frequently associated with epidemic cholera. vpsT upregulation was primarily dependent on the virulence master regulator AphA. Of possible clinical relevance was the observation that V. cholerae in the INT 407-associated biofilms was significantly more resistant to antibiotics than unadhered planktonic cells.
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Affiliation(s)
- Chirantana Sengupta
- Infectious Diseases and Immunology Division, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India
| | - Oindrilla Mukherjee
- Infectious Diseases and Immunology Division, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India
| | - Rukhsana Chowdhury
- Infectious Diseases and Immunology Division, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India
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22
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Chowdhury G, Bhadra RK, Bag S, Pazhani GP, Das B, Basu P, Nagamani K, Nandy RK, Mukhopadhyay AK, Ramamurthy T. Rugose atypical Vibrio cholerae O1 El Tor responsible for 2009 cholera outbreak in India. J Med Microbiol 2016; 65:1130-1136. [PMID: 27561681 DOI: 10.1099/jmm.0.000344] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vibrio cholerae causes cholera outbreaks in endemic regions where the water quality and sanitation facilities remain poor. Apart from biotype and serotype changes, V. cholerae undergoes phase variation, which results in the generation of two morphologically different variants termed smooth and rugose. In this study, 12 rugose (R-VC) and 6 smooth (S-VC) V. cholerae O1 Ogawa isolates were identified in a cholera outbreak that occurred in Hyderabad, India. Antimicrobial susceptibility results showed that all the isolates were resistant to ampicillin, furazolidone and nalidixic acid. In addition, R-VC isolates were resistant to ciprofloxacin (92 %), streptomycin (92 %), erythromycin (83 %), trimethoprim-sulfamethoxazole (75 %) and tetracycline (75 %). Based on the ctxB gene analysis, all the isolates were identified as El Tor variant with mutation in two positions of ctxB, similar to the classical biotype. The R-VC isolates specifically showed excessive biofilm formation and were comparatively less motile. In addition, the majority of these isolates (~83 %) displayed random mutations in the hapR gene, which encodes haemagglutinin protease regulatory protein. In the PFGE analysis, R-VC and S-VC were placed in distinct clusters but remained clonally related. In the ribotyping analysis, all the R-VC isolates exhibited R-III pattern, which is a prevailing type among the current El Tor isolates. A hapR deletion mutant generated using an S-VC isolate expressed rugose phenotype. To our knowledge, this is the first report on the association of rugose V. cholerae O1 in a large cholera outbreak with extended antimicrobial resistance and random mutations in the haemagglutinin protease regulatory protein encoding gene (hapR).
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Affiliation(s)
- Goutam Chowdhury
- Department of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Rupak K Bhadra
- Infectious Diseases and Immunology Division, CSIR - Indian Institute of Chemical Biology, Kolkata, India
| | - Satyabrata Bag
- Infectious Diseases and Immunology Division, CSIR - Indian Institute of Chemical Biology, Kolkata, India.,Center for Human Microbial Ecology, Translational Health Science and Technology Institute, Faridabad, India
| | - Gururaja P Pazhani
- National Institute of Pharmaceutical Education and Research, Kolkata, India
| | - Bhabatosh Das
- Center for Human Microbial Ecology, Translational Health Science and Technology Institute, Faridabad, India
| | - Pallabi Basu
- Infectious Diseases and Immunology Division, CSIR - Indian Institute of Chemical Biology, Kolkata, India
| | - K Nagamani
- Division of Microbiology, Gandhi Medical College, Secunderabad, India
| | - Ranjan K Nandy
- Department of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Asish K Mukhopadhyay
- Department of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Thandavarayan Ramamurthy
- Center for Human Microbial Ecology, Translational Health Science and Technology Institute, Faridabad, India.,Department of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
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23
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Affiliation(s)
- Gerard C L Wong
- Department of Bioengineering, Department of Chemistry and Biochemistry, California Nano Systems Institute, University of California, Los Angeles, CA 90095-1600
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24
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Onischenko GG, Popova AY, Kutyrev VV, Smirnova NI, Scherbakova SA, Moskvitina EA, Titova SV. ACTUAL PROBLEMS OF EPIDEMIOLOGIC CONTROL, LABORATORY DIAGNOSTICS AND PROPHYLAXIS OF CHOLERA IN RUSSIAN FEDERATION. ACTA ACUST UNITED AC 2016. [DOI: 10.36233/0372-9311-2016-1-89-101] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | - A. Yu. Popova
- Federal Service for Surveillance on Consumer Rights’ Protection and Human Wellbeing
| | - V. V. Kutyrev
- Russian Research Institute for Plague Control «Microbe»
| | | | | | | | - S. V. Titova
- Rostov-on-Don Research Institute for Plague Control
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Paranjpye RN, Nilsson WB, Liermann M, Hilborn ED, George BJ, Li Q, Bill BD, Trainer VL, Strom MS, Sandifer PA. Environmental influences on the seasonal distribution of Vibrio parahaemolyticus in the Pacific Northwest of the USA. FEMS Microbiol Ecol 2015; 91:fiv121. [PMID: 26454066 DOI: 10.1093/femsec/fiv121] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2015] [Indexed: 11/13/2022] Open
Abstract
Populations of Vibrio parahaemolyticus in the environment can be influenced by numerous factors. We assessed the correlation of total (tl+) and potentially virulent (tdh+) V. parahaemolyticus in water with three harmful algal bloom (HAB) genera (Pseudo-nitzschia, Alexandrium and Dinophysis), the abundance of diatoms and dinoflagellates, chlorophyll-a and temperature, salinity and macronutrients at five sites in Washington State from 2008-2009. The variability in V. parahaemolyticus density was explained predominantly by strong seasonal trends where maximum densities occurred in June, 2 months prior to the highest seasonal water temperature. In spite of large geographic differences in temperature, salinity and nutrients, there was little evidence of corresponding differences in V. parahaemolyticus density. In addition, there was no evident relationship between V. parahaemolyticus and indices of HAB genera, perhaps due to a lack of significant HAB events during the sampling period. The only nutrient significantly associated with V. parahaemolyticus density after accounting for the seasonal trend was silicate. This negative relationship may be caused by a shift in cell wall structure for some diatom species to a chitinous substrate preferred by V. parahaemolyticus. Results from our study differ from those in other regions corroborating previous findings that environmental factors that trigger vibrio and HAB events may differ depending on geographic locations. Therefore caution should be used when applying results from one region to another.
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Affiliation(s)
- Rohinee N Paranjpye
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard E, Seattle, WA 98112, USA
| | - William B Nilsson
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard E, Seattle, WA 98112, USA
| | - Martin Liermann
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard E, Seattle, WA 98112, USA
| | - Elizabeth D Hilborn
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Laboratory, Research Triangle Park, NC 27709, USA
| | - Barbara J George
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Laboratory, Research Triangle Park, NC 27709, USA
| | - Quanlin Li
- Biostatistics and Bioinformatics Research Center, Samuel Oschin Comprehensive Cancer Institute, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Brian D Bill
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard E, Seattle, WA 98112, USA
| | - Vera L Trainer
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard E, Seattle, WA 98112, USA
| | - Mark S Strom
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard E, Seattle, WA 98112, USA
| | - Paul A Sandifer
- Hollings Marine Laboratory, National Ocean Service, National Oceanic and Atmospheric Administration, 331 Fort Johnson Road, Charleston, SC 29412, USA
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Jones CJ, Utada A, Davis KR, Thongsomboon W, Zamorano Sanchez D, Banakar V, Cegelski L, Wong GCL, Yildiz FH. C-di-GMP Regulates Motile to Sessile Transition by Modulating MshA Pili Biogenesis and Near-Surface Motility Behavior in Vibrio cholerae. PLoS Pathog 2015; 11:e1005068. [PMID: 26505896 PMCID: PMC4624765 DOI: 10.1371/journal.ppat.1005068] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 07/06/2015] [Indexed: 01/11/2023] Open
Abstract
In many bacteria, including Vibrio cholerae, cyclic dimeric guanosine monophosphate (c-di-GMP) controls the motile to biofilm life style switch. Yet, little is known about how this occurs. In this study, we report that changes in c-di-GMP concentration impact the biosynthesis of the MshA pili, resulting in altered motility and biofilm phenotypes in V. cholerae. Previously, we reported that cdgJ encodes a c-di-GMP phosphodiesterase and a ΔcdgJ mutant has reduced motility and enhanced biofilm formation. Here we show that loss of the genes required for the mannose-sensitive hemagglutinin (MshA) pilus biogenesis restores motility in the ΔcdgJ mutant. Mutations of the predicted ATPase proteins mshE or pilT, responsible for polymerizing and depolymerizing MshA pili, impair near surface motility behavior and initial surface attachment dynamics. A ΔcdgJ mutant has enhanced surface attachment, while the ΔcdgJmshA mutant phenocopies the high motility and low attachment phenotypes observed in a ΔmshA strain. Elevated concentrations of c-di-GMP enhance surface MshA pilus production. MshE, but not PilT binds c-di-GMP directly, establishing a mechanism for c-di-GMP signaling input in MshA pilus production. Collectively, our results suggest that the dynamic nature of the MshA pilus established by the assembly and disassembly of pilin subunits is essential for transition from the motile to sessile lifestyle and that c-di-GMP affects MshA pilus assembly and function through direct interactions with the MshE ATPase.
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Affiliation(s)
- Christopher J. Jones
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Andrew Utada
- Department of Bioengineering, Department of Chemistry and Biochemistry, California Nano Systems Institute, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Kimberly R. Davis
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Wiriya Thongsomboon
- Department of Chemistry, Stanford University, Stanford, California, United States of America
| | - David Zamorano Sanchez
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Vinita Banakar
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, Stanford, California, United States of America
| | - Gerard C. L. Wong
- Department of Bioengineering, Department of Chemistry and Biochemistry, California Nano Systems Institute, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Fitnat H. Yildiz
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
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Teschler JK, Zamorano-Sánchez D, Utada AS, Warner CJA, Wong GCL, Linington RG, Yildiz FH. Living in the matrix: assembly and control of Vibrio cholerae biofilms. Nat Rev Microbiol 2015; 13:255-68. [PMID: 25895940 PMCID: PMC4437738 DOI: 10.1038/nrmicro3433] [Citation(s) in RCA: 260] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nearly all bacteria form biofilms as a strategy for survival and persistence. Biofilms are associated with biotic and abiotic surfaces and are composed of aggregates of cells that are encased by a self-produced or acquired extracellular matrix. Vibrio cholerae has been studied as a model organism for understanding biofilm formation in environmental pathogens, as it spends much of its life cycle outside of the human host in the aquatic environment. Given the important role of biofilm formation in the V. cholerae life cycle, the molecular mechanisms underlying this process and the signals that trigger biofilm assembly or dispersal have been areas of intense investigation over the past 20 years. In this Review, we discuss V. cholerae surface attachment, various matrix components and the regulatory networks controlling biofilm formation.
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Affiliation(s)
- Jennifer K. Teschler
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - David Zamorano-Sánchez
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Andrew S. Utada
- Bioengineering Department, Chemistry and Biochemistry Department, and NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Christopher J. A. Warner
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Gerard C. L. Wong
- Bioengineering Department, Chemistry and Biochemistry Department, and NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Roger G. Linington
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Fitnat H. Yildiz
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
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Identification and characterization of VpsR and VpsT binding sites in Vibrio cholerae. J Bacteriol 2015; 197:1221-35. [PMID: 25622616 DOI: 10.1128/jb.02439-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The ability to form biofilms is critical for environmental survival and transmission of Vibrio cholerae, a facultative human pathogen responsible for the disease cholera. Biofilm formation is controlled by several transcriptional regulators and alternative sigma factors. In this study, we report that the two main positive regulators of biofilm formation, VpsR and VpsT, bind to nonoverlapping target sequences in the regulatory region of vpsL in vitro. VpsR binds to a proximal site (the R1 box) as well as a distal site (the R2 box) with respect to the transcriptional start site identified upstream of vpsL. The VpsT binding site (the T box) is located between the R1 and R2 boxes. While mutations in the T and R boxes resulted in a decrease in vpsL expression, deletion of the T and R2 boxes resulted in an increase in vpsL expression. Analysis of the role of H-NS in vpsL expression revealed that deletion of hns resulted in enhanced vpsL expression. The level of vpsL expression was higher in an hns vpsT double mutant than in the parental strain but lower than that in an hns mutant. In silico analysis of the regulatory regions of the VpsR and VpsT targets resulted in the identification of conserved recognition motifs for VpsR and VpsT and revealed that operons involved in biofilm formation and vpsT are coregulated by VpsR and VpsT. Furthermore, a comparative genomics analysis revealed substantial variability in the promoter region of the vpsT and vpsL genes among extant V. cholerae isolates, suggesting that regulation of biofilm formation is under active selection. IMPORTANCE Vibrio cholerae causes cholera and is a natural inhabitant of aquatic environments. One critical factor that is important for environmental survival and transmission of V. cholerae is the microbe's ability to form biofilms, which are surface-associated communities encased in a matrix composed of the exopolysaccharide VPS (Vibrio polysaccharide), proteins, and nucleic acids. Two proteins, VpsR and VpsT, positively regulate VPS production and biofilm formation. We characterized the structural features of the promoter of the vpsL gene, determined the target sequences recognized by VpsT and VpsR, and analyzed their distribution and conservation patterns in multiple V. cholerae isolates. This work fills a fundamental gap in our understanding of the regulatory mechanisms employed by the master regulators VpsR and VpsT in controlling biofilm matrix production.
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Song T, Sabharwal D, Gurung JM, Cheng AT, Sjöström AE, Yildiz FH, Uhlin BE, Wai SN. Vibrio cholerae utilizes direct sRNA regulation in expression of a biofilm matrix protein. PLoS One 2014; 9:e101280. [PMID: 25054332 PMCID: PMC4108314 DOI: 10.1371/journal.pone.0101280] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 06/05/2014] [Indexed: 11/18/2022] Open
Abstract
Vibrio cholerae biofilms contain exopolysaccharide and three matrix proteins RbmA, RbmC and Bap1. While much is known about exopolysaccharide regulation, little is known about the mechanisms by which the matrix protein components of biofilms are regulated. VrrA is a conserved, 140-nt sRNA of V. cholerae, whose expression is controlled by sigma factor σE. In this study, we demonstrate that VrrA negatively regulates rbmC translation by pairing to the 5′ untranslated region of the rbmC transcript and that this regulation is not stringently dependent on the RNA chaperone protein Hfq. These results point to VrrA as a molecular link between the σE-regulon and biofilm formation in V. cholerae. In addition, VrrA represents the first example of direct regulation of sRNA on biofilm matrix component, by-passing global master regulators.
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Affiliation(s)
- Tianyan Song
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Dharmesh Sabharwal
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Jyoti Mohan Gurung
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Andrew T. Cheng
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Annika E. Sjöström
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Fitnat H. Yildiz
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Bernt Eric Uhlin
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Sun Nyunt Wai
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
- * E-mail:
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Akoachere JFTK, Masalla TN, Njom HA. Multi-drug resistant toxigenic Vibrio cholerae O1 is persistent in water sources in New Bell-Douala, Cameroon. BMC Infect Dis 2013; 13:366. [PMID: 23919373 PMCID: PMC3750389 DOI: 10.1186/1471-2334-13-366] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 07/31/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cholera has been endemic in Douala, since 1971 when it was first recorded in Cameroon. Outbreaks have often started in slum areas of the city including New Bell. Despite the devastating nature of outbreaks, always resulting in high mortality and morbidity, a paucity of information exists on the reservoirs of the causative agent, V. cholerae, and factors maintaining its persistence. This has complicated disease prevention, resulting in frequent outbreaks of cholera. We investigated water sources in New Bell for contamination with V. cholerae O1 with pathogenic potential, to highlight their role in disease transmission. Antibiotic susceptibility pattern of isolates and the environmental factors maintaining its persistence were investigated. METHOD Water samples from various sources (taps, dug wells, streams) were analyzed for contamination with V. cholerae O1 using standard methods. Antibiotic susceptibility was determined by disc diffusion method. Pathogenic potential of isolates was determined by analyzing for genes for cholera toxin (ctx), toxin co-regulated pilus (tcpA), and zonula occludens toxin (zot) by PCR. Physico-chemical characteristics of water (pH, temperature and salinity) were investigated using standard methods. The Spearman's Rank correlation was used to analyze the relationship between physico-chemical factors and the occurrence of V. cholerae O1. Differences were considered significant at P≤0.05. RESULTS Twenty-five V. cholerae O1 strains were isolated from stream and well samples in both dry and rainy seasons. Twenty-three (92%) isolates were multidrug resistant. All isolates had genes for at least one virulence factor. Cholera toxin gene was detected in 7 isolates. Of the 15 isolates positive for tcpA gene, two had Classical type tcpA while 13 had tcpA El Tor. All tcpA Classical positive isolates were positive for ctx gene. Isolates were grouped into nine genotypes based on the genes analyzed. pH and salinity significantly correlated with isolation of V. cholerae O1. CONCLUSION Multidrug resistant Vibrio cholerae O1 with pathogenic potential is present in some wells and streams in study area. pH and salinity are among the factors maintaining the persistence of the organism. Findings indicate an urgent need for potable water supply in study area and in addition, regular disinfection of water from contaminated sources to prevent outbreak of cholera.
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Affiliation(s)
- Jane-Francis Tatah Kihla Akoachere
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Laboratory for Emerging Infectious Diseases, Faculty of Science, University of Buea, Buea, Cameroon
| | - Thomas Njinuwoh Masalla
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
- Laboratory for Emerging Infectious Diseases, Faculty of Science, University of Buea, Buea, Cameroon
| | - Henry Akum Njom
- Laboratory for Emerging Infectious Diseases, Faculty of Science, University of Buea, Buea, Cameroon
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Serological cross-reaction between O-antigens of Shigella dysenteriae type 4 and an environmental Escherichia albertii isolate. Curr Microbiol 2013; 67:590-5. [PMID: 23748967 DOI: 10.1007/s00284-013-0405-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 05/27/2013] [Indexed: 10/26/2022]
Abstract
An environmental freshwater bacterial isolate, DM104, appearing as Shigella-like colonies on selective agar plates was found to show strong and specific serological cross-reactivity with Shigella dysenteriae type 4. Biochemical identification according to the analytical profile index, molecular serotyping by restriction of the amplified O-antigen gene cluster (rfb-RFLP), together with phylogenetic analysis of the 16S rRNA gene and multi-locus sequence analysis, identified the isolate as Escherichia albertii. rfb-RFLP of DM104, revealed a profile different from that of S. dysenteriae type 4. However, western blot analysis of extracted lipopolysaccharides demonstrated strong cross-reactivity with S. dysenteriae type 4 using specific monovalent antisera and a lipopolysaccharide gel banding profile similar to that of S. dysenteriae type 4. The observed O-antigen cross-reaction between an E. albertii isolate and S. dysenteriae extends our knowledge of the extent of O-antigen cross-reaction within the Escherichia/Shigella group of organisms, and offers the possibility of using DM104 and similar cross-reacting strains as shigellosis vaccine candidates.
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Structural basis for biofilm formation via the Vibrio cholerae matrix protein RbmA. J Bacteriol 2013; 195:3277-86. [PMID: 23687270 DOI: 10.1128/jb.00374-13] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
During the transition from a free-swimming, single-cell lifestyle to a sessile, multicellular state called a biofilm, bacteria produce and secrete an extracellular matrix comprised of nucleic acids, exopolysaccharides, and adhesion proteins. The Vibrio cholerae biofilm matrix contains three major protein components, RbmA, Bap1, and RbmC, which are unique to Vibrio cholerae and appear to support biofilm formation at particular steps in the process. Here, we focus on RbmA, a structural protein with an unknown fold. RbmA participates in the early cell-cell adhesion events and is found throughout the biofilm where it localizes to cell-cell contact sites. We determined crystal structures of RbmA and revealed that the protein folds into tandem fibronectin type III (FnIII) folds. The protein is dimeric in solution and in crystals, with the dimer interface displaying a surface groove that is lined with several positively charged residues. Structure-guided mutagenesis studies establish a crucial role for this surface patch for RbmA function. On the basis of the structure, we hypothesize that RbmA serves as a tether by maintaining flexible linkages between cells and the extracellular matrix.
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Azmuda N, Rahman MZ, Sultana M, Jenssen EL, Khan SI, Birkeland NK. Evidence of interspecies O antigen gene cluster transfer between Shigella boydii 15 and Escherichia fergusonii. APMIS 2012; 120:959-66. [PMID: 23030400 DOI: 10.1111/j.1600-0463.2012.02926.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 05/01/2012] [Indexed: 01/24/2023]
Abstract
An environmental bacterial isolate, Iso10, previously found to show serological cross-reactivity with type-specific Shigella boydii 15 antisera was subjected to further molecular and serological analyses that revealed interspecies transfer of the O antigen gene cluster. Western blot analysis of Iso10 cell surface extracts and purified lipopolysaccharides demonstrated strong cross-reactivity with S. boydii 15-specific monovalent antisera and a lipopolysaccharide gel banding profile similar to that of S. boydii 15. Biochemical and phylogenetic analyses identified the Iso10 isolate as Escherichia fergusonii. O antigen gene cluster analyses of Iso10, carried out by restriction fragment length analysis of the amplified ~10-kb O antigen-encoding gene cluster, revealed a profile highly similar to that of S. boydii 15, confirming the presence of the S. boydii 15 somatic antigen in Iso10. To the best of our knowledge, this is the first report of interspecies transfer of O antigen-encoding genes between S. boydii and E. fergusonii, and it has implications for our understanding of the role of lateral gene transfer in the emergence of novel Shigella serotypes.
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Affiliation(s)
- Nafisa Azmuda
- Department of Microbiology, University of Dhaka, Dhaka, Bangladesh
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Impact of summer cattle grazing on the Sierra Nevada watershed: aquatic algae and bacteria. JOURNAL OF ENVIRONMENTAL AND PUBLIC HEALTH 2012; 2012:760108. [PMID: 22505950 PMCID: PMC3312331 DOI: 10.1155/2012/760108] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Accepted: 11/07/2011] [Indexed: 11/29/2022]
Abstract
Introduction. We evaluated periphytic algal and microbial communities to assess the influence of human and cattle impact on Sierra water quality. Methods. 64 sites (lakes and streams from Lake Tahoe to Sequoia National Park, California) were sampled for suspended indicator bacteria and algae following standardized procedures. The potential for nonpoint pollution was divided into three categories: cattle-grazing areas (C), recreation use areas (R), or remote wildlife areas (W). Results. Periphyton was found at 100% of C sites, 89% of R sites, but only 25% of W sites. Eleven species of periphytic algae were identified, including Zygnema, Ulothrix, Chlorella, Spirogyra, mixed Diatoms, and Cladophoria. Mean benthic algae coverage was 66% at C sites compared to 2% at W sites (P < 0.05). The prevalence of E. coli associated with periphyton was 100% at C sites, 25% of R sites, and 0% of W sites. Mean E. coli CFU/gm of algae detected was: C = 173,000, R = 700, W = 0. (P < 0.05). Analysis of neighboring water for E. coli bacteria >100 CFU/100 mL: C = 91%, R = 8%, W = 0 (P < 0.05). Conclusion. Higher periphytic algal biomass and uniform presence of periphyton-attached E. coli corresponded to watersheds exposed to summer cattle grazing. These differences suggest cattle grazing compromises water quality.
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Valeru SP, Wai SN, Saeed A, Sandström G, Abd H. ToxR of Vibrio cholerae affects biofilm, rugosity and survival with Acanthamoeba castellanii. BMC Res Notes 2012; 5:33. [PMID: 22248371 PMCID: PMC3292481 DOI: 10.1186/1756-0500-5-33] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 01/16/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Vibrio cholerae causes the diarrheal disease cholera and utilizes different survival strategies in aquatic environments. V. cholerae can survive as free-living or in association with zooplankton and can build biofilm and rugose colonies. The bacterium expresses cholera toxin (CT) and toxin-coregulated pilus (TCP) as the main virulence factors. These factors are co-regulated by a transcriptional regulator ToxR, which modulates expression of outer membrane proteins (OmpU) and (OmpT). The aims of this study were to disclose the role of ToxR in expression of OmpU and OmpT, biofilm and rugose colony formation as well as in association with the free-living amoeba Acanthamoeba castellanii at different temperatures. RESULTS The toxR mutant V. cholerae produced OmpT, significant biofilm and rugose colonies compared to the wild type that produced OmpU, decreased biofilm and did not form rugoes colonies at 30°C. Interestingly, neither the wild type nor toxR mutant strain could form rugose colonies in association with the amoebae. However, during the association with the amoebae it was observed that A. castellanii enhanced survival of V. cholerae wild type compared to toxR mutant strain at 37°C. CONCLUSIONS ToxR does seem to play some regulatory role in the OmpT/OmpU expression shift, the changes in biofilm, rugosity and survival with A. castellanii, suggesting a new role for this regulatory protein in the environments.
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Affiliation(s)
- Soni P Valeru
- Karolinska Institute, Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska University Hospital, Huddinge, SE-141 86, Stockholm, Sweden.
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Rahman MZ, Azmuda N, Hossain MJ, Sultana M, Khan SI, Birkeland NK. Recovery and Characterization of Environmental Variants of Shigella flexneri from Surface Water in Bangladesh. Curr Microbiol 2011; 63:372-6. [DOI: 10.1007/s00284-011-9992-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 07/28/2011] [Indexed: 10/17/2022]
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Holmner A, Mackenzie A, Krengel U. Molecular basis of cholera blood-group dependence and implications for a world characterized by climate change. FEBS Lett 2010; 584:2548-55. [PMID: 20417206 DOI: 10.1016/j.febslet.2010.03.050] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 03/04/2010] [Indexed: 11/17/2022]
Abstract
Climate change has the potential to increase the threat of water-borne diseases, through rises in temperature and sea-level, and precipitation variability. Cholera poses a particular threat, and the need to develop better intervention tools is imminent. Cholera infections are particularly severe for blood group O individuals, who are less protected by the current vaccines. Here we derive a hypothesis as to the molecular origins of blood-group dependence of this disease, based on relevant epidemiological, clinical and molecular data, and give suggestions on how to plan prevention strategies, and develop novel and improved pharmaceuticals.
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Affiliation(s)
- Asa Holmner
- Department of Biomedical Engineering and Informatics, Västerbotten County Council, Umeå, Sweden
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Shikuma NJ, Hadfield MG. Marine biofilms on submerged surfaces are a reservoir for Escherichia coli and Vibrio cholerae. BIOFOULING 2010; 26:39-46. [PMID: 20390555 DOI: 10.1080/08927010903282814] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The enteric bacterium and potential human pathogen, Escherichia coli, is known to persist in tropical soils and coastal waters. Vibrio cholerae causes the disease cholera and inhabits marine environments including microbial films on submerged surfaces. The abundances of E. coli and V. cholerae were quantified in biofilm and water-column samples from three harbors in Honolulu, Hawai'i, which differ in their local and international ship traffic. E. coli and, in some cases V. cholerae, occurred in relatively high abundances in marine biofilms formed on abiotic surfaces, including the exterior hulls of ships. The community fingerprints of the biofilms and the water harboring these pathogens were further analyzed. The community compositions of biofilms from different locations were more similar to each other than to water-column communities from the same locations. These results suggest that biofilms are an overlooked reservoir and a source of dissemination for E. coli and V. cholerae.
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Affiliation(s)
- Nicholas J Shikuma
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064, USA.
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Nelson EJ, Harris JB, Morris JG, Calderwood SB, Camilli A. Cholera transmission: the host, pathogen and bacteriophage dynamic. Nat Rev Microbiol 2009; 7:693-702. [PMID: 19756008 PMCID: PMC3842031 DOI: 10.1038/nrmicro2204] [Citation(s) in RCA: 343] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Zimbabwe offers the most recent example of the tragedy that befalls a country and its people when cholera strikes. The 2008-2009 outbreak rapidly spread across every province and brought rates of mortality similar to those witnessed as a consequence of cholera infections a hundred years ago. In this Review we highlight the advances that will help to unravel how interactions between the host, the bacterial pathogen and the lytic bacteriophage might propel and quench cholera outbreaks in endemic settings and in emergent epidemic regions such as Zimbabwe.
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Affiliation(s)
- Eric J Nelson
- Howard Hughes Medical Institute, Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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Islam MS, Sharker MAY, Rheman S, Hossain S, Mahmud ZH, Islam MS, Uddin AMK, Yunus M, Osman MS, Ernst R, Rector I, Larson CP, Luby SP, Endtz HP, Cravioto A. Effects of local climate variability on transmission dynamics of cholera in Matlab, Bangladesh. Trans R Soc Trop Med Hyg 2009; 103:1165-70. [PMID: 19477477 DOI: 10.1016/j.trstmh.2009.04.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 04/23/2009] [Accepted: 04/23/2009] [Indexed: 11/29/2022] Open
Abstract
Cholera is considered as a model for climate-related infectious diseases. In Bangladesh, cholera epidemics occur during summer and winter seasons, but it is not known how climate variability influences the seasonality of cholera. Therefore, the variability pattern of cholera events was studied in relation to the variation in local climate variables in Matlab, Bangladesh. Classification and regression tree (CART) and principal component analysis (PCA) were used to study the dependency and variability pattern of monthly total cholera cases. An average temperature <23.25 degrees C corresponded to the lowest average cholera occurrence (23 cases/month). At a temperature of >or=23.25 degrees C and sunshine <4.13h/day, the cholera occurrence was 39 cases/month. With increased sunshine (>or=4.13h/day) and temperature (23.25-28.66 degrees C), the second highest cholera occurrence (44 cases/month) was observed. When the sunshine was >or=4.13h/day and the temperature was >28.66 degrees C, the highest cholera occurrence (54 cases/month) was observed. These results demonstrate that in summer and winter seasons in Bangladesh, temperature and sunshine hours compensate each other for higher cholera incidence. The synergistic effect of temperature and sunshine hours provided the highest number of cholera cases.
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Affiliation(s)
- M S Islam
- International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), GPO Box 128, Dhaka 1000, Bangladesh.
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Bilecen K, Yildiz FH. Identification of a calcium-controlled negative regulatory system affecting Vibrio cholerae biofilm formation. Environ Microbiol 2009; 11:2015-29. [PMID: 19397680 DOI: 10.1111/j.1462-2920.2009.01923.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vibrio cholerae's capacity to cause outbreaks of cholera is linked to its survival and adaptability to changes in aquatic environments. One of the environmental conditions that can vary in V. cholerae's natural aquatic habitats is calcium (Ca(+2)). In this study, we investigated the response of V. cholerae to changes in extracellular Ca(2+) levels. Whole-genome expression profiling revealed that Ca(2+) decreased the expression of genes required for biofilm matrix production. Luria-Bertani (LB) medium supplemented with Ca(2+) (LBCa(2+)) caused V. cholerae to form biofilms with decreased thickness and increased roughness, as compared with biofilms formed in LB. Furthermore, addition of Ca(2+) led to dissolution in biofilms. Transcription of two genes encoding a two-component regulatory system pair, now termed calcium-regulated sensor (carS) and regulator (carR), was decreased in cells grown in LBCa(2+). Analysis of null and overexpression alleles of carS and carR revealed that expression of vps (Vibriopolysaccharide) genes and biofilm formation are negatively regulated by the CarRS two-component regulatory system. Through epistasis analysis we determined that CarR acts in parallel with HapR, the negative regulator of vps gene expression.
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Affiliation(s)
- Kivanc Bilecen
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064, USA
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Nelson EJ, Chowdhury A, Flynn J, Schild S, Bourassa L, Shao Y, LaRocque RC, Calderwood SB, Qadri F, Camilli A. Transmission of Vibrio cholerae is antagonized by lytic phage and entry into the aquatic environment. PLoS Pathog 2008; 4:e1000187. [PMID: 18949027 PMCID: PMC2563029 DOI: 10.1371/journal.ppat.1000187] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Accepted: 09/24/2008] [Indexed: 11/21/2022] Open
Abstract
Cholera outbreaks are proposed to propagate in explosive cycles powered by hyperinfectious Vibrio cholerae and quenched by lytic vibriophage. However, studies to elucidate how these factors affect transmission are lacking because the field experiments are almost intractable. One reason for this is that V. cholerae loses the ability to culture upon transfer to pond water. This phenotype is called the active but non-culturable state (ABNC; an alternative term is viable but non-culturable) because these cells maintain the capacity for metabolic activity. ABNC bacteria may serve as the environmental reservoir for outbreaks but rigorous animal studies to test this hypothesis have not been conducted. In this project, we wanted to determine the relevance of ABNC cells to transmission as well as the impact lytic phage have on V. cholerae as the bacteria enter the ABNC state. Rice-water stool that naturally harbored lytic phage or in vitro derived V. cholerae were incubated in a pond microcosm, and the culturability, infectious dose, and transcriptome were assayed over 24 h. The data show that the major contributors to infection are culturable V. cholerae and not ABNC cells. Phage did not affect colonization immediately after shedding from the patients because the phage titer was too low. However, V. cholerae failed to colonize the small intestine after 24 h of incubation in pond water—the point when the phage and ABNC cell titers were highest. The transcriptional analysis traced the transformation into the non-infectious ABNC state and supports models for the adaptation to nutrient poor aquatic environments. Phage had an undetectable impact on this adaptation. Taken together, the rise of ABNC cells and lytic phage blocked transmission. Thus, there is a fitness advantage if V. cholerae can make a rapid transfer to the next host before these negative selective pressures compound in the aquatic environment. The biological factors that control the transmission of water-borne pathogens like Vibrio cholerae during outbreaks are ill defined. In this study, a molecular analysis of the active but non-culturable (ABNC) state of V. cholerae provides insights into the physiology of environmental adaptation. The ABNC state, lytic phage, and hyperinfectivity were concurrently followed as V. cholerae passaged from cholera patients to an aquatic reservoir. The relevance to transmission of each factor was weighed against the others. As the bacteria transitioned from the patient to pond water, there was a rapid decay into the ABNC state and a rise of lytic phage that compounded to block transmission in a mouse model. These two factors give reason for V. cholerae to make a quick transit through the environment and onto the next human host. Thus, in over-crowded locations with failed water infrastructure, the opportunity for fast transmission coupled with the increased infectivity and culturability of recently shed V. cholerae creates a charged setting for explosive cholera outbreaks.
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Affiliation(s)
- Eric J. Nelson
- Howard Hughes Medical Institute and the Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | | | - James Flynn
- Tufts Expression Array Core (TEAC) Facility, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Stefan Schild
- Institut fuer Molekulare Biowissenschaften, Karl-Franzens-Universitaet Graz, Graz, Austria
| | - Lori Bourassa
- Howard Hughes Medical Institute and the Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Yue Shao
- Tufts Expression Array Core (TEAC) Facility, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Regina C. LaRocque
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America, and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Stephen B. Calderwood
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America, and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Andrew Camilli
- Howard Hughes Medical Institute and the Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Identification and characterization of cyclic diguanylate signaling systems controlling rugosity in Vibrio cholerae. J Bacteriol 2008; 190:7392-405. [PMID: 18790873 DOI: 10.1128/jb.00564-08] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Vibrio cholerae, the causative agent of the disease cholera, can generate rugose variants that have an increased capacity to form biofilms. Rugosity and biofilm formation are critical for the environmental survival and transmission of the pathogen, and these processes are controlled by cyclic diguanylate (c-di-GMP) signaling systems. c-di-GMP is produced by diguanylate cyclases (DGCs) and degraded by phosphodiesterases (PDEs). Proteins that contain GGDEF domains act as DGCs, whereas proteins that contain EAL or HD-GYP domains act as PDEs. In the V. cholerae genome there are 62 genes that are predicted to encode proteins capable of modulating the cellular c-di-GMP concentration. We previously identified two DGCs, VpvC and CdgA, that can control the switch between smooth and rugose. To identify other c-di-GMP signaling proteins involved in rugosity, we generated in-frame deletion mutants of all genes predicted to encode proteins with GGDEF and EAL domains and then searched for mutants with altered rugosity. In this study, we identified two new genes, cdgG and cdgH, involved in rugosity control. We determined that CdgH acts as a DGC and positively regulates rugosity, whereas CdgG does not have DGC activity and negatively regulates rugosity. In addition, epistasis analysis with CdgG, CdgH, and other DGCs and PDEs controlling rugosity revealed that CdgG and CdgH act in parallel with previously identified c-di-GMP signaling proteins to control rugosity in V. cholerae. We also determined that PilZ domain-containing c-di-GMP binding proteins contribute minimally to rugosity, indicating that there are additional c-di-GMP binding proteins controlling rugosity in V. cholerae.
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Huq A, Whitehouse CA, Grim CJ, Alam M, Colwell RR. Biofilms in water, its role and impact in human disease transmission. Curr Opin Biotechnol 2008; 19:244-7. [PMID: 18524568 DOI: 10.1016/j.copbio.2008.04.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 04/07/2008] [Accepted: 04/21/2008] [Indexed: 11/28/2022]
Abstract
Understanding the mechanism of biofilm formation is the first step in determining its function and, thereby, its impact and role in the environment. Extensive studies accomplished during the past few years have elucidated the genetics and biochemistry of biofilm formation. Cell-to-cell communication, that is, quorum sensing, is a key factor in the initiation of biofilm. Occurrence of viable but nonculturable bacteria, including Vibrio cholerae in biofilms has been reported and most likely such cells were overlooked previously because appropriate methods of detection were not employed. For this reason discovery and investigation of this important bacterial ecological niche in the environment were impeded.
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Affiliation(s)
- Anwar Huq
- University of Maryland, Maryland Pathogen Research Institute, 3132 Bioscience Research, Building #413, College Park, MD 20742, United States.
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VanFossen AL, Lewis DL, Nichols JD, Kelly RM. Polysaccharide Degradation and Synthesis by Extremely Thermophilic Anaerobes. Ann N Y Acad Sci 2008; 1125:322-37. [DOI: 10.1196/annals.1419.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Leal NC, de Araújo Figueiroa ACT, Cavalcanti VO, da Silva SC, Leal-Balbino TC, de Almeida AMP, Hofer E. Characterization of Vibrio cholerae isolated from the aquatic basins of the State of Pernambuco, Brazil. Trans R Soc Trop Med Hyg 2008; 102:272-6. [PMID: 18258274 DOI: 10.1016/j.trstmh.2007.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 12/10/2007] [Accepted: 12/10/2007] [Indexed: 10/22/2022] Open
Abstract
Through a continuous bacteriological monitoring programme carried out by the Health Secretariat of the State of Pernambuco, Brazil, two isolates of Vibrio cholerae O1 El Tor Ogawa were discovered in an endemic area in 2001, during a cholera inactive period, along with six V. cholerae non-O1/non-O139 strains and two Aeromonas veronii biovar sobria strains showing an unusual characteristic of agglutination with O1 antiserum. Between that time and 2005, eight other O1 isolates were found. The virulence genes present in the V. cholerae differed among strains, with only three O1 strains harboring the ctxA gene. The O1 and some non-O1/non-O139 strains displayed identical patterns of amplification of the 16S-23S intergenic spacer region. RAPD of the 10 V. cholerae O1 strains, with the two primers used, revealed heterogeneity. The presence of V. cholerae carrying virulence genes in the aquatic basins examined confirms that they constitute a vibrio reservoir during a cholera inactive period, thus strengthening the argument for a continuous monitoring programme and preventative measures for cholera, mainly in the areas where the supply of drinking water is deficient.
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Affiliation(s)
- Nilma Cintra Leal
- Centro de Pesquisas Aggeu Magalhães/fiocruz, Av. Moraes Rego s/n, Campus da UFPE, Cidade Universitária, 50670-420, Recife, PE, Brazil.
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