1
|
Huang Z, Li Y, Yu K, Ma L, Pang B, Qin Q, Li J, Wang D, Gao H, Kan B. Genome-wide expanding of genetic evolution and potential pathogenicity in Vibrio alginolyticus. Emerg Microbes Infect 2024; 13:2350164. [PMID: 38687697 PMCID: PMC11132748 DOI: 10.1080/22221751.2024.2350164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/26/2024] [Indexed: 05/02/2024]
Abstract
Vibrio alginolyticus, an emergent species of Vibrio genus, exists in aquatic and marine environments. It has undergone genetic diversification, but its detailed genomic diversity is still unclear. Here, we performed a multi-dimensional comparative genomic analysis to explore the population phylogeny, virulence-related genes and potential drug resistance genes of 184 V. alginolyticus isolates. Although genetic diversity is complex, we analysed the population structure using three sub-datasets, including the subdivision for three lineages into sublineages and the distribution of strains in the marine ecological niche. Accessory genes, most of which reclassified V. alginolyticus genomes as different but with relatively close affinities, were nonuniformly distributed among these isolates. We demonstrated that the spread of some post-evolutionary isolates (mainly L3 strains isolated from Chinese territorial seas) was likely to be closely related to human activities, whereas other more ancestral strains (strains in the L1 and L2) tended to be locally endemic and formed clonal complex groups. In terms of pathogenicity, the potential virulence factors were mainly associated with toxin, adherence, motility, chemotaxis, and the type III secretion system (T3SS). We also found five types of antibacterial drug resistance genes. The prevalence of β-lactam resistance genes was 100%, which indicated that there may be a potential risk of natural resistance to β-lactam drugs. Our study reveals insights into genomic characteristics, evolution and potential virulence-associated gene profiles of V. alginolyticus.
Collapse
Affiliation(s)
- Zhenzhou Huang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
- Hangzhou Center for Disease Control and Prevention, Zhejiang, People’s Republic of China
| | - Yanjun Li
- The Sixth Medical Center of PLA General Hospital, Beijing, People’s Republic of China
| | - Keyi Yu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Lizhi Ma
- The Third Medical Center, Chinese PLA (People’s Liberation Army) General Hospital, Beijing, People’s Republic of China
| | - Bo Pang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Qin Qin
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Jie Li
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Duochun Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - He Gao
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| | - Biao Kan
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
| |
Collapse
|
2
|
Rangarajan AA, Schroeder JW, Hurto RL, Severin GB, Pell ME, Hsieh ML, Waters CM, Freddolino L. Negative feedback of cyclic di-GMP levels optimizes switching between sessile and motile lifestyles in Vibrio cholerae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.01.610008. [PMID: 39257796 PMCID: PMC11383701 DOI: 10.1101/2024.09.01.610008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
The signaling molecule cyclic di-GMP (cdG) controls the switch between bacterial motility and biofilm production, and fluctuations in cellular levels of cdG have been implicated in Vibrio cholerae pathogenesis. Intracellular concentrations of cdG are controlled by the interplay of diguanylate cyclase (DGC) enzymes, which synthesize cdG to promote biofilms, and phosphodiesterase (PDE) enzymes, which hydrolyse cdG to drive motility. To track the complete regulatory logic of how V. cholerae responds to changing cdG levels, we followed a timecourse of overexpression of either the V. harveyi diguanylate cyclase QrgB or a variant of QrgB lacking catalytic activity (QrgB*). We find that QrgB increases cdG levels relative to QrgB* for 30 minutes after overexpression, but the effect of QrgB on cdG levels plateaus at 30 minutes, indicating tight adaptive control of cdG levels. In contrast, loss of VpsR, a master regulator activating biofilm formation upon binding to cdG, leads to higher baseline levels of cdG and continuously increasing cdG through 60 minutes after QrgB induction, revealing the existence of a negative feedback loop on cdG levels operating through VpsR. Through a combination of RNA polymerase ChIP-seq, RNA-seq, and genetic approaches, we show that transcription of a gene encoding a PDE, cdgC , is activated by VpsR at high cdG concentrations, mediating this negative feedback on cdG levels. We further identify a transcript encoded within, and antisense to, the cdgC open reading frame which we name s RNA n egative r egulator of C dgC (SnrC). RNA polymerase ChIP-seq and RNA-seq demonstrate SnrC to be expressed specifically under conditions of high cdG in the absence of VpsR. Ectopic SnrC expression increases cdG levels in a manner dependent on CdgC, demonstrating that its effect on cdG levels is likely through interference with CdgC production. Further, although cells lacking cdgC exhibit enhanced biofilm formation, these mutants are outcompeted by wild type V. cholerae in colonization assays that reward a combination of attachment, dispersal, and motility behaviors. These results underscore the importance of negative feedback regulation of cdG to maintain appropriate homeostatic levels for efficient transitioning between biofilm formation and motility, both of which are necessary over the course of the V. cholerae infection cycle.
Collapse
|
3
|
Graham LA, Hansen T, Yang Y, Sherik M, Ye Q, Soares BP, Kinrade B, Guo S, Davies PL. Adhesin domains responsible for binding bacteria to surfaces they colonize project outwards from companion split domains. Proteins 2024; 92:933-945. [PMID: 38591850 DOI: 10.1002/prot.26689] [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: 01/09/2024] [Revised: 03/07/2024] [Accepted: 03/26/2024] [Indexed: 04/10/2024]
Abstract
Bacterial adhesins attach their hosts to surfaces that the bacteria will colonize. This surface adhesion occurs through specific ligand-binding domains located towards the distal end of the long adhesin molecules. However, recognizing which of the many adhesin domains are structural and which are ligand binding has been difficult up to now. Here we have used the protein structure modeling program AlphaFold2 to predict structures for these giant 0.2- to 1.5-megadalton proteins. Crystal structures previously solved for several adhesin regions are in good agreement with the models. Whereas most adhesin domains are linked in a linear fashion through their N- and C-terminal ends, ligand-binding domains can be recognized by budding out from a companion core domain so that their ligand-binding sites are projected away from the axis of the adhesin for maximal exposure to their targets. These companion domains are "split" in their continuity by projecting the ligand-binding domain outwards. The "split domains" are mostly β-sandwich extender modules, but other domains like a β-solenoid can serve the same function. Bioinformatic analyses of Gram-negative bacterial sequences revealed wide variety ligand-binding domains are used in their Repeats-in-Toxin adhesins. The ligands for many of these domains have yet to be identified but known ligands include various cell-surface glycans, proteins, and even ice. Recognizing the ligands to which the adhesins bind could lead to ways of blocking colonization by bacterial pathogens. Engineering different ligand-binding domains into an adhesin has the potential to change the surfaces to which bacteria bind.
Collapse
Affiliation(s)
- Laurie A Graham
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Thomas Hansen
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Yanzhi Yang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Mustafa Sherik
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Qilu Ye
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Blake P Soares
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Brett Kinrade
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Shuaiqi Guo
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Peter L Davies
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| |
Collapse
|
4
|
Zhang Q, Alter T, Fleischmann S. Non-O1/Non-O139 Vibrio cholerae-An Underestimated Foodborne Pathogen? An Overview of Its Virulence Genes and Regulatory Systems Involved in Pathogenesis. Microorganisms 2024; 12:818. [PMID: 38674762 PMCID: PMC11052320 DOI: 10.3390/microorganisms12040818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/05/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
In recent years, the number of foodborne infections with non-O1 and non-O139 Vibrio cholerae (NOVC) has increased worldwide. These have ranged from sporadic infection cases to localized outbreaks. The majority of case reports describe self-limiting gastroenteritis. However, severe gastroenteritis and even cholera-like symptoms have also been described. All reported diarrheal cases can be traced back to the consumption of contaminated seafood. As climate change alters the habitats and distribution patterns of aquatic bacteria, there is a possibility that the number of infections and outbreaks caused by Vibrio spp. will further increase, especially in countries where raw or undercooked seafood is consumed or clean drinking water is lacking. Against this background, this review article focuses on a possible infection pathway and how NOVC can survive in the human host after oral ingestion, colonize intestinal epithelial cells, express virulence factors causing diarrhea, and is excreted by the human host to return to the environment.
Collapse
Affiliation(s)
| | | | - Susanne Fleischmann
- Institute of Food Safety and Food Hygiene, School of Veterinary Medicine, Freie Universität Berlin, Königsweg 69, 14163 Berlin, Germany; (Q.Z.); (T.A.)
| |
Collapse
|
5
|
Grant NA, Donkor GY, Sontz JT, Soto W, Waters CM. Deployment of a Vibrio cholerae ordered transposon mutant library in a quorum-competent genetic background. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.31.564941. [PMID: 37961142 PMCID: PMC10634969 DOI: 10.1101/2023.10.31.564941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Vibrio cholerae, the causative agent of cholera, has sparked seven pandemics in recent centuries, with the current one being the most prolonged. V. cholerae's pathogenesis hinges on its ability to switch between low and high cell density gene regulatory states, enabling transmission between host and the environment. Previously, a transposon mutant library for V. cholerae was created to support investigations aimed toward uncovering the genetic determinants of its pathogenesis. However, subsequent sequencing uncovered a mutation in the gene luxO of the parent strain, rendering mutants unable to exhibit high cell density behaviors. In this study, we used chitin-independent natural transformation to move transposon insertions from these low cell density mutants into a wildtype genomic background. Library transfer was aided by a novel gDNA extraction we developed using thymol, which also showed high lysis-specificity for Vibrio. The resulting Grant Library comprises 3,102 unique transposon mutants, covering 79.8% of V. cholerae's open reading frames. Whole genome sequencing of randomly selected mutants demonstrates 100% precision in transposon transfer to cognate genomic positions of the recipient strain. Notably, in no instance did the luxO mutation transfer into the wildtype background. Our research uncovered density-dependent epistasis in growth on inosine, an immunomodulatory metabolite secreted by gut bacteria that is implicated in enhancing gut barrier functions. Additionally, Grant Library mutants retain the plasmid that enables rapid, scarless genomic editing. In summary, the Grant Library reintroduces organismal relevant genetic contexts absent in the low cell density locked library equivalent.
Collapse
Affiliation(s)
- Nkrumah A. Grant
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, IL
- Department of Microbiology, Genetics, and Immunology, Michigan State University, East Lansing MI
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI
| | | | - Jordan T. Sontz
- MSU College of Osteopathic Medicine, Michigan State University, East Lansing, MI
| | - William Soto
- Department of Biology, College of William and Mary, Williamsburg, VA
| | - Christopher M. Waters
- Department of Microbiology, Genetics, and Immunology, Michigan State University, East Lansing MI
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI
- MSU College of Osteopathic Medicine, Michigan State University, East Lansing, MI
| |
Collapse
|
6
|
Sajeevan A, Ramamurthy T, Solomon AP. Vibrio cholerae virulence and its suppression through the quorum-sensing system. Crit Rev Microbiol 2024:1-22. [PMID: 38441045 DOI: 10.1080/1040841x.2024.2320823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 02/10/2024] [Indexed: 03/06/2024]
Abstract
Vibrio cholerae is a cholera-causing pathogen known to instigate severe contagious diarrhea that affects millions globally. Survival of vibrios depend on a combination of multicellular responses and adapt to changes that prevail in the environment. This process is achieved through a strong communication at the cellular level, the process has been recognized as quorum sensing (QS). The severity of infection is highly dependent on the QS of vibrios in the gut milieu. The quorum may exist in a low/high cell density (LCD/HCD) state to exert a positive or negative response to control the regulatory pathogenic networks. The impact of this regulation reflects on the transition of pathogenic V. cholerae from the environment to infect humans and cause outbreaks or epidemics of cholera. In this context, the review portrays various regulatory processes and associated virulent pathways, which maneuver and control LCD and HCD states for their survival in the host. Although several treatment options are existing, promotion of therapeutics by exploiting the virulence network may potentiate ineffective antibiotics to manage cholera. In addition, this approach is also useful in resource-limited settings, where the accessibility to antibiotics or conventional therapeutic options is limited.
Collapse
Affiliation(s)
- Anusree Sajeevan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - Thandavarayan Ramamurthy
- Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Disease, Kolkata, India
| | - Adline Princy Solomon
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| |
Collapse
|
7
|
Sherik M, Eves R, Guo S, Lloyd CJ, Klose KE, Davies PL. Sugar-binding and split domain combinations in repeats-in-toxin adhesins from Vibrio cholerae and Aeromonas veronii mediate cell-surface recognition and hemolytic activities. mBio 2024; 15:e0229123. [PMID: 38171003 PMCID: PMC10865825 DOI: 10.1128/mbio.02291-23] [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: 08/23/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
Abstract
Many pathogenic Gram-negative bacteria use repeats-in-toxin adhesins for colonization and biofilm formation. In the cholera agent Vibrio cholerae, flagellar-regulated hemagglutinin A (FrhA) enables these functions. Using bioinformatic analysis, a sugar-binding domain was identified in FrhA adjacent to a domain of unknown function. AlphaFold2 indicated the boundaries of both domains to be slightly shorter than previously predicted and assisted in the recognition of the unknown domain as a split immunoglobulin-like fold that can assist in projecting the sugar-binding domain toward its target. The AlphaFold2-predicted structure is in excellent agreement with the molecular envelope obtained from small-angle X-ray scattering analysis of a recombinant construct spanning the sugar-binding and unknown domains. This two-domain construct was probed by glycan micro-array screening and showed binding to mammalian fucosylated glycans, some of which are characteristic erythrocyte markers and intestinal cell epitopes. Isothermal titration calorimetry further showed the construct-bound l-fucose with a Kd of 21 µM. Strikingly, this recombinant protein construct bound and lysed erythrocytes in a concentration-dependent manner, and its hemolytic activity was blocked by the addition of l-fucose. A protein ortholog construct from Aeromonas veronii was also produced and showed a similar glycan-binding pattern, binding affinity, erythrocyte-binding, and hemolytic activities. As demonstrated here with Hep-2 cells, fucose-based inhibitors of this sugar-binding domain can potentially be developed to block colonization by V. cholerae and other pathogenic bacteria that share this adhesin domain.IMPORTANCEThe bacterium, Vibrio cholerae, which causes cholera, uses an adhesion protein to stick to human cells and begin the infection process. One part of this adhesin protein binds to a particular sugar, fucose, on the surface of the target cells. This binding can lead to colonization and killing of the cells by the bacteria. Adding l-fucose to the bacteria before they bind to the human cells can prevent attachment and has promise as a preventative drug to protect against cholera.
Collapse
Affiliation(s)
- Mustafa Sherik
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Robert Eves
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Shuaiqi Guo
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Cameron J. Lloyd
- South Texas Center for Emerging Infectious Diseases and Department of Molecular Microbiology and Immunology, University of Texas San Antonio, San Antonio, Texas, USA
| | - Karl E. Klose
- South Texas Center for Emerging Infectious Diseases and Department of Molecular Microbiology and Immunology, University of Texas San Antonio, San Antonio, Texas, USA
| | - Peter L. Davies
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| |
Collapse
|
8
|
Zangara MT, Darwish L, Coombes BK. Characterizing the Pathogenic Potential of Crohn's Disease-Associated Adherent-Invasive Escherichia coli. EcoSal Plus 2023; 11:eesp00182022. [PMID: 37220071 PMCID: PMC10729932 DOI: 10.1128/ecosalplus.esp-0018-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/04/2023] [Indexed: 01/28/2024]
Abstract
The microbiome of Crohn's disease (CD) patients is composed of a microbial community that is considered dysbiotic and proinflammatory in nature. The overrepresentation of Enterobacteriaceae species is a common feature of the CD microbiome, and much attention has been given to understanding the pathogenic role this feature plays in disease activity. Over 2 decades ago, a new Escherichia coli subtype called adherent-invasive E. coli (AIEC) was isolated and linked to ileal Crohn's disease. Since the isolation of the first AIEC strain, additional AIEC strains have been isolated from both inflammatory bowel disease (IBD) patients and non-IBD individuals using the original in vitro phenotypic characterization methods. Identification of a definitive molecular marker of the AIEC pathotype has been elusive; however, significant advancements have been made in understanding the genetic, metabolic, and virulence determinants of AIEC infection biology. Here, we review the current knowledge of AIEC pathogenesis to provide additional, objective measures that could be considered in defining AIEC and their pathogenic potential.
Collapse
Affiliation(s)
- Megan T. Zangara
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Lena Darwish
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Brian K. Coombes
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario, Canada
- Farncombe Family Digestive Health Research Institute, Hamilton, Ontario, Canada
| |
Collapse
|
9
|
Zhang Q, Alter T, Strauch E, Hammerl JA, Schwartz K, Borowiak M, Deneke C, Fleischmann S. Genetic and Phenotypic Virulence Potential of Non-O1/Non-O139 Vibrio cholerae Isolated from German Retail Seafood. Microorganisms 2023; 11:2751. [PMID: 38004762 PMCID: PMC10672755 DOI: 10.3390/microorganisms11112751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 10/28/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Non-O1 and non-O139 Vibrio cholerae (NOVC) can cause gastrointestinal infections in humans. Contaminated food, especially seafood, is an important source of human infections. In this study, the virulence potential of 63 NOVC strains isolated from retail seafood were characterized at the genotypic and phenotypic levels. Although no strain encoded the cholera toxin (CTX) and the toxin-coregulated pilus (TCP), several virulence factors, including the HlyA hemolysin, the cholix toxin ChxA, the heat-stable enterotoxin Stn, and genes coding for the type 3 and type 6 secretion systems, were detected. All strains showed hemolytic activity against human and sheep erythrocytes: 90% (n = 57) formed a strong biofilm, 52% (n = 33) were highly motile at 37 °C, and only 8% (n = 5) and 14% (n = 9) could resist ≥60% and ≥40% human serum, respectively. Biofilm formation and toxin regulation genes were also detected. cgMLST analysis demonstrated that NOVC strains from seafood cluster with clinical NOVC strains. Antimicrobial susceptibility testing (AST) results in the identification of five strains that developed non-wildtype phenotypes (medium and resistant) against the substances of the classes of beta-lactams (including penicillin, carbapenem, and cephalosporin), polymyxins, and sulphonamides. The phenotypic resistance pattern could be partially attributed to the acquired resistance determinants identified via in silico analysis. Our results showed differences in the virulence potential of the analyzed NOVC isolated from retail seafood products, which may be considered for further pathogenicity evaluation and the risk assessment of NOVC isolates in future seafood monitoring.
Collapse
Affiliation(s)
- Quantao Zhang
- Institute of Food Safety and Food Hygiene, School of Veterinary Medicine, Freie Universität Berlin, Königsweg 69, 14163 Berlin, Germany
| | - Thomas Alter
- Institute of Food Safety and Food Hygiene, School of Veterinary Medicine, Freie Universität Berlin, Königsweg 69, 14163 Berlin, Germany
| | - Eckhard Strauch
- Department Biological Safety, German Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany; (E.S.); (J.A.H.)
| | - Jens Andre Hammerl
- Department Biological Safety, German Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany; (E.S.); (J.A.H.)
| | - Keike Schwartz
- Department Biological Safety, German Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany; (E.S.); (J.A.H.)
| | - Maria Borowiak
- Department Biological Safety, German Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany; (E.S.); (J.A.H.)
| | - Carlus Deneke
- Department Biological Safety, German Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany; (E.S.); (J.A.H.)
| | - Susanne Fleischmann
- Institute of Food Safety and Food Hygiene, School of Veterinary Medicine, Freie Universität Berlin, Königsweg 69, 14163 Berlin, Germany
| |
Collapse
|
10
|
Falco A, Villaquirán-Muriel MÁ, Gallo Pérez JD, Mondragón-Quiguanas A, Aranaga C, Correa A. Identification of Vibrio metschnikovii and Vibrio injensis Isolated from Leachate Ponds: Characterization of Their Antibiotic Resistance and Virulence-Associated Genes. Antibiotics (Basel) 2023; 12:1571. [PMID: 37998773 PMCID: PMC10668802 DOI: 10.3390/antibiotics12111571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/22/2023] [Accepted: 10/25/2023] [Indexed: 11/25/2023] Open
Abstract
This study aimed to evaluate the antibiotic resistance of 22 environmental Vibrio metschnikovii isolates and 1 Vibrio injensis isolate from landfill leachates in southwestern Colombia. Isolates were identified by Matrix-Assisted Laser Desorption/Ionization-Time-Of-Flight (MALDI-TOF), and 16S ribosomal RNA gene sequencing. Analysis of the susceptibility to six antibacterial agents by the Kirby-Bauer method showed susceptibility of all the isolates to ciprofloxacin and imipenem. We recorded resistance to beta-lactams and aminoglycosides, but no multidrug resistance was observed. The genome of one of the isolates was sequenced to determine the pathogenic potential of V. injensis. Genes associated with virulence were identified, including for flagellar synthesis, biofilm formation, and hemolysins, among others. These results demonstrate that landfill leachates are potential reservoirs of antibiotic-resistant and pathogenic bacteria and highlight the importance of monitoring Vibrio species in different aquatic environments.
Collapse
Affiliation(s)
- Aura Falco
- Microbiology, Industry and Environment Research Group (GIMIA), Department of Basic Sciences, Santiago de Cali University, Cali 760035, Colombia (A.C.)
| | - Miguel Ángel Villaquirán-Muriel
- Microbiology, Industry and Environment Research Group (GIMIA), Department of Basic Sciences, Santiago de Cali University, Cali 760035, Colombia (A.C.)
| | - José David Gallo Pérez
- Microbiology, Industry and Environment Research Group (GIMIA), Department of Basic Sciences, Santiago de Cali University, Cali 760035, Colombia (A.C.)
| | - Alejandra Mondragón-Quiguanas
- Microbiology, Industry and Environment Research Group (GIMIA), Department of Basic Sciences, Santiago de Cali University, Cali 760035, Colombia (A.C.)
| | - Carlos Aranaga
- Chemistry and Biotechnology Research Group (QUIBIO), Department of Basic Sciences, Santiago de Cali University, Cali 760035, Colombia;
| | - Adriana Correa
- Microbiology, Industry and Environment Research Group (GIMIA), Department of Basic Sciences, Santiago de Cali University, Cali 760035, Colombia (A.C.)
| |
Collapse
|
11
|
Lloyd CJ, Guo S, Kinrade B, Zahiri H, Eves R, Ali SK, Yildiz F, Voets IK, Davies PL, Klose KE. A peptide-binding domain shared with an Antarctic bacterium facilitates Vibrio cholerae human cell binding and intestinal colonization. Proc Natl Acad Sci U S A 2023; 120:e2308238120. [PMID: 37729203 PMCID: PMC10523503 DOI: 10.1073/pnas.2308238120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 07/31/2023] [Indexed: 09/22/2023] Open
Abstract
Vibrio cholerae, the causative agent of the disease cholera, is responsible for multiple pandemics. V. cholerae binds to and colonizes the gastrointestinal tract within the human host, as well as various surfaces in the marine environment (e.g., zooplankton) during interepidemic periods. A large adhesin, the Flagellar Regulated Hemagglutinin A (FrhA), enhances binding to erythrocytes and epithelial cells and enhances intestinal colonization. We identified a peptide-binding domain (PBD) within FrhA that mediates hemagglutination, binding to epithelial cells, intestinal colonization, and facilitates biofilm formation. Intriguingly, this domain is also found in the ice-binding protein of the Antarctic bacterium Marinomonas primoryensis, where it mediates binding to diatoms. Peptide inhibitors of the M. primoryensis PBD inhibit V. cholerae binding to human cells as well as to diatoms and inhibit biofilm formation. Moreover, the M. primoryensis PBD inserted into FrhA allows V. cholerae to bind human cells and colonize the intestine and also enhances biofilm formation, demonstrating the interchangeability of the PBD from these bacteria. Importantly, peptide inhibitors of PBD reduce V. cholerae intestinal colonization in infant mice. These studies demonstrate how V. cholerae uses a PBD shared with a diatom-binding Antarctic bacterium to facilitate intestinal colonization in humans and biofilm formation in the environment.
Collapse
Affiliation(s)
- Cameron J. Lloyd
- South Texas Center for Emerging Infectious Diseases, University of Texas, San Antonio, TX78249
- Department of Molecular Microbiology and Immunology, University of Texas, San Antonio, TX78249
| | - Shuaiqi Guo
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ONK7L 3N6, Canada
| | - Brett Kinrade
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ONK7L 3N6, Canada
| | - Hossein Zahiri
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ONK7L 3N6, Canada
| | - Robert Eves
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ONK7L 3N6, Canada
| | - Syed Khalid Ali
- South Texas Center for Emerging Infectious Diseases, University of Texas, San Antonio, TX78249
- Department of Molecular Microbiology and Immunology, University of Texas, San Antonio, TX78249
| | - Fitnat Yildiz
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA95064
| | - Ilja K. Voets
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, Eindhoven5612, the Netherlands
| | - Peter L. Davies
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ONK7L 3N6, Canada
| | - Karl E. Klose
- South Texas Center for Emerging Infectious Diseases, University of Texas, San Antonio, TX78249
- Department of Molecular Microbiology and Immunology, University of Texas, San Antonio, TX78249
| |
Collapse
|
12
|
Chakraborty S, Agarwal S, Bakshi A, Dey S, Biswas M, Ghosh B, Dasgupta J. The N-terminal FleQ domain of the Vibrio cholerae flagellar master regulator FlrA plays pivotal structural roles in stabilizing its active state. FEBS Lett 2023; 597:2161-2177. [PMID: 37402215 DOI: 10.1002/1873-3468.14693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 07/06/2023]
Abstract
In Vibrio cholerae, the master regulator FlrA controls transcription of downstream flagellar genes in a σ54 -dependent manner. However, the molecular basis of regulation by VcFlrA, which contains a phosphorylation-deficient N-terminal FleQ domain, has remained elusive. Our studies on VcFlrA, four of its constructs, and a mutant showed that the AAA+ domain of VcFlrA, with or without the linker 'L', remains in ATPase-deficient monomeric states. By contrast, the FleQ domain plays a pivotal role in promoting higher-order functional oligomers, providing the required conformation to 'L' for ATP/cyclic di-GMP (c-di-GMP) binding. The crystal structure of VcFlrA-FleQ at 2.0 Å suggests that distinct structural features of VcFlrA-FleQ presumably assist in inter-domain packing. VcFlrA at a high concentration forms ATPase-efficient oligomers when the intracellular c-di-GMP level is low. Conversely, excess c-di-GMP locks VcFlrA in a non-functional lower oligomeric state, causing repression of flagellar biosynthesis.
Collapse
Affiliation(s)
| | | | - Arindam Bakshi
- Department of Biotechnology, St Xavier's College, Kolkata, India
| | - Sanjay Dey
- Department of Biotechnology, St Xavier's College, Kolkata, India
| | - Maitree Biswas
- Department of Biotechnology, St Xavier's College, Kolkata, India
| | - Biplab Ghosh
- Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai, India
| | - Jhimli Dasgupta
- Department of Biotechnology, St Xavier's College, Kolkata, India
| |
Collapse
|
13
|
Smith TJ, Sundarraman D, Melancon E, Desban L, Parthasarathy R, Guillemin K. A mucin-regulated adhesin determines the spatial organization and inflammatory character of a bacterial symbiont in the vertebrate gut. Cell Host Microbe 2023; 31:1371-1385.e6. [PMID: 37516109 PMCID: PMC10492631 DOI: 10.1016/j.chom.2023.07.003] [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: 07/12/2022] [Revised: 05/11/2023] [Accepted: 07/06/2023] [Indexed: 07/31/2023]
Abstract
In a healthy gut, microbes are often aggregated with host mucus, yet the molecular basis for this organization and its impact on intestinal health are unclear. Mucus is a viscous physical barrier separating resident microbes from epithelia, but it also provides glycan cues that regulate microbial behaviors. Here, we describe a mucin-sensing pathway in an Aeromonas symbiont of zebrafish, Aer01. In response to the mucin-associated glycan N-acetylglucosamine, a sensor kinase regulates the expression of an aggregation-promoting adhesin we named MbpA. Upon MbpA disruption, Aer01 colonizes to normal levels but is largely planktonic and more pro-inflammatory. Increasing cell surface MbpA rescues these traits. MbpA-like adhesins are common in human-associated bacteria, and the expression of an Akkermansia muciniphila MbpA-like adhesin in MbpA-deficient Aer01 restores lumenal aggregation and reverses its pro-inflammatory character. Our work demonstrates how resident bacteria use mucin glycans to modulate behaviors congruent with host health.
Collapse
Affiliation(s)
- T Jarrod Smith
- Institute of Molecular Biology, University of Oregon, Eugene, OR, USA
| | - Deepika Sundarraman
- Department of Physics and Materials Science Institute, University of Oregon, Eugene, OR, USA
| | - Ellie Melancon
- Institute of Neuroscience, University of Oregon, Eugene, OR, USA
| | - Laura Desban
- Institute of Neuroscience, University of Oregon, Eugene, OR, USA
| | - Raghuveer Parthasarathy
- Department of Physics and Materials Science Institute, University of Oregon, Eugene, OR, USA
| | - Karen Guillemin
- Institute of Molecular Biology, University of Oregon, Eugene, OR, USA; Institute of Neuroscience, University of Oregon, Eugene, OR, USA; Humans and the Microbiome Program, Canadian Institute for Advanced Research, Toronto, ON, Canada.
| |
Collapse
|
14
|
Vidakovic L, Mikhaleva S, Jeckel H, Nisnevich V, Strenger K, Neuhaus K, Raveendran K, Ben-Moshe NB, Aznaourova M, Nosho K, Drescher A, Schmeck B, Schulte LN, Persat A, Avraham R, Drescher K. Biofilm formation on human immune cells is a multicellular predation strategy of Vibrio cholerae. Cell 2023; 186:2690-2704.e20. [PMID: 37295405 PMCID: PMC10256282 DOI: 10.1016/j.cell.2023.05.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 01/26/2023] [Accepted: 05/09/2023] [Indexed: 06/12/2023]
Abstract
Biofilm formation is generally recognized as a bacterial defense mechanism against environmental threats, including antibiotics, bacteriophages, and leukocytes of the human immune system. Here, we show that for the human pathogen Vibrio cholerae, biofilm formation is not only a protective trait but also an aggressive trait to collectively predate different immune cells. We find that V. cholerae forms biofilms on the eukaryotic cell surface using an extracellular matrix comprising primarily mannose-sensitive hemagglutinin pili, toxin-coregulated pili, and the secreted colonization factor TcpF, which differs from the matrix composition of biofilms on other surfaces. These biofilms encase immune cells and establish a high local concentration of a secreted hemolysin to kill the immune cells before the biofilms disperse in a c-di-GMP-dependent manner. Together, these results uncover how bacteria employ biofilm formation as a multicellular strategy to invert the typical relationship between human immune cells as the hunters and bacteria as the hunted.
Collapse
Affiliation(s)
| | - Sofya Mikhaleva
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Hannah Jeckel
- Biozentrum, University of Basel, 4056 Basel, Switzerland; Department of Physics, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Valerya Nisnevich
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | | | - Konstantin Neuhaus
- Biozentrum, University of Basel, 4056 Basel, Switzerland; Department of Physics, Philipps-Universität Marburg, 35043 Marburg, Germany
| | | | - Noa Bossel Ben-Moshe
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Marina Aznaourova
- Institute for Lung Research, Center for Synthetic Microbiology (SYNMIKRO), Universities of Giessen and Marburg Lung Center, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Kazuki Nosho
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Antje Drescher
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Bernd Schmeck
- Institute for Lung Research, Center for Synthetic Microbiology (SYNMIKRO), Universities of Giessen and Marburg Lung Center, Philipps-Universität Marburg, 35043 Marburg, Germany; Department of Pulmonary and Critical Care Medicine, University Medical Center Marburg, 35043 Marburg, Germany; German Center for Infection Research (DZIF), 35043 Marburg, Germany; German Center for Lung Research (DZL), 35043 Marburg, Germany; Institute for Lung Health, 35392 Giessen, Germany
| | - Leon N Schulte
- Institute for Lung Research, Center for Synthetic Microbiology (SYNMIKRO), Universities of Giessen and Marburg Lung Center, Philipps-Universität Marburg, 35043 Marburg, Germany; German Center for Lung Research (DZL), 35043 Marburg, Germany
| | - Alexandre Persat
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Roi Avraham
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Knut Drescher
- Biozentrum, University of Basel, 4056 Basel, Switzerland.
| |
Collapse
|
15
|
Montero DA, Vidal RM, Velasco J, George S, Lucero Y, Gómez LA, Carreño LJ, García-Betancourt R, O’Ryan M. Vibrio cholerae, classification, pathogenesis, immune response, and trends in vaccine development. Front Med (Lausanne) 2023; 10:1155751. [PMID: 37215733 PMCID: PMC10196187 DOI: 10.3389/fmed.2023.1155751] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/14/2023] [Indexed: 05/24/2023] Open
Abstract
Vibrio cholerae is the causative agent of cholera, a highly contagious diarrheal disease affecting millions worldwide each year. Cholera is a major public health problem, primarily in countries with poor sanitary conditions and regions affected by natural disasters, where access to safe drinking water is limited. In this narrative review, we aim to summarize the current understanding of the evolution of virulence and pathogenesis of V. cholerae as well as provide an overview of the immune response against this pathogen. We highlight that V. cholerae has a remarkable ability to adapt and evolve, which is a global concern because it increases the risk of cholera outbreaks and the spread of the disease to new regions, making its control even more challenging. Furthermore, we show that this pathogen expresses several virulence factors enabling it to efficiently colonize the human intestine and cause cholera. A cumulative body of work also shows that V. cholerae infection triggers an inflammatory response that influences the development of immune memory against cholera. Lastly, we reviewed the status of licensed cholera vaccines, those undergoing clinical evaluation, and recent progress in developing next-generation vaccines. This review offers a comprehensive view of V. cholerae and identifies knowledge gaps that must be addressed to develop more effective cholera vaccines.
Collapse
Affiliation(s)
- David A. Montero
- Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Roberto M. Vidal
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Instituto Milenio de Inmunología e Inmunoterapia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Juliana Velasco
- Unidad de Paciente Crítico, Clínica Hospital del Profesor, Santiago, Chile
- Programa de Formación de Especialista en Medicina de Urgencia, Universidad Andrés Bello, Santiago, Chile
| | - Sergio George
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Yalda Lucero
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Departamento de Pediatría y Cirugía Infantil, Hospital Dr. Roberto del Rio, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Leonardo A. Gómez
- Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Leandro J. Carreño
- Instituto Milenio de Inmunología e Inmunoterapia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Programa de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Richard García-Betancourt
- Programa de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Miguel O’Ryan
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| |
Collapse
|
16
|
Kitts G, Rogers A, Teschler JK, Park JH, Trebino MA, Chaudry I, Erill I, Yildiz FH. The Rvv two-component regulatory system regulates biofilm formation and colonization in Vibrio cholerae. PLoS Pathog 2023; 19:e1011415. [PMID: 37216386 PMCID: PMC10237652 DOI: 10.1371/journal.ppat.1011415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 06/02/2023] [Accepted: 05/10/2023] [Indexed: 05/24/2023] Open
Abstract
The facultative human pathogen, Vibrio cholerae, employs two-component signal transduction systems (TCS) to sense and respond to environmental signals encountered during its infection cycle. TCSs consist of a sensor histidine kinase (HK) and a response regulator (RR); the V. cholerae genome encodes 43 HKs and 49 RRs, of which 25 are predicted to be cognate pairs. Using deletion mutants of each HK gene, we analyzed the transcription of vpsL, a biofilm gene required for Vibrio polysaccharide and biofilm formation. We found that a V. cholerae TCS that had not been studied before, now termed Rvv, controls biofilm gene transcription. The Rvv TCS is part of a three-gene operon that is present in 30% of Vibrionales species. The rvv operon encodes RvvA, the HK; RvvB, the cognate RR; and RvvC, a protein of unknown function. Deletion of rvvA increased transcription of biofilm genes and altered biofilm formation, while deletion of rvvB or rvvC lead to no changes in biofilm gene transcription. The phenotypes observed in ΔrvvA depend on RvvB. Mutating RvvB to mimic constitutively active and inactive versions of the RR only impacted phenotypes in the ΔrvvA genetic background. Mutating the conserved residue required for kinase activity in RvvA did not affect phenotypes, whereas mutation of the conserved residue required for phosphatase activity mimicked the phenotype of the rvvA mutant. Furthermore, ΔrvvA displayed a significant colonization defect which was dependent on RvvB and RvvB phosphorylation state, but not on VPS production. We found that RvvA's phosphatase activity regulates biofilm gene transcription, biofilm formation, and colonization phenotypes. This is the first systematic analysis of the role of V. cholerae HKs in biofilm gene transcription and resulted in the identification of a new regulator of biofilm formation and virulence, advancing our understanding of the role TCSs play in regulating these critical cellular processes in V. cholerae.
Collapse
Affiliation(s)
- Giordan Kitts
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Andrew Rogers
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Jennifer K. Teschler
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Jin Hwan Park
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Michael A. Trebino
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Issac Chaudry
- Department of Biological Sciences, University of Maryland Baltimore County (UMBC), Baltimore, Maryland, United States of America
| | - Ivan Erill
- Department of Biological Sciences, University of Maryland Baltimore County (UMBC), Baltimore, Maryland, 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
| |
Collapse
|
17
|
Lloyd CJ, Klose KE. The Vibrio Polar Flagellum: Structure and Regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:77-97. [PMID: 36792872 DOI: 10.1007/978-3-031-22997-8_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Here we discuss the structure and regulation of the Vibrio flagellum and its role in the virulence of pathogenic species. We will cover some of the novel insights into the structure of this nanomachine that have recently been enabled by cryoelectron tomography. We will also highlight the recent genetic studies that have increased our understanding in flagellar synthesis specifically at the bacterial cell pole, temporal regulation of flagellar genes, and how the flagellum enables directional motility through Run-Reverse-Flick cycles.
Collapse
Affiliation(s)
- Cameron J Lloyd
- South Texas Center for Emerging Infectious Diseases, University of Texas San Antonio, San Antonio, TX, USA.,Department of Molecular Microbiology and Immunology, University of Texas San Antonio, San Antonio, TX, USA
| | - Karl E Klose
- South Texas Center for Emerging Infectious Diseases, University of Texas San Antonio, San Antonio, TX, USA. .,Department of Molecular Microbiology and Immunology, University of Texas San Antonio, San Antonio, TX, USA.
| |
Collapse
|
18
|
Zou M, Wang K, Zhao J, Lu H, Yang H, Huang M, Wang L, Wang G, Huang J, Min X. DegS protease regulates the motility, chemotaxis, and colonization of Vibrio cholerae. Front Microbiol 2023; 14:1159986. [PMID: 37089576 PMCID: PMC10113495 DOI: 10.3389/fmicb.2023.1159986] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 03/14/2023] [Indexed: 04/25/2023] Open
Abstract
In bacteria, DegS protease functions as an activating factor of the σE envelope stress response system, which ultimately activates the transcription of stress response genes in the cytoplasm. On the basis of high-throughput RNA sequencing, we have previously found that degS knockout inhibits the expression of flagellum synthesis- and chemotaxis-related genes, thereby indicating that DegS may be involved in the regulation of V. cholerae motility. In this study, we examined the relationships between DegS and motility in V. cholerae. Swimming motility and chemotaxis assays revealed that degS or rpoE deletion promotes a substantial reduction in the motility and chemotaxis of V. cholerae, whereas these activities were restored in ΔdegS::degS and ΔdegSΔrseA strains, indicating that DegS is partially dependent on σE to positively regulate V. cholerae activity. Gene-act network analysis revealed that the cAMP-CRP-RpoS signaling pathway, which plays an important role in flagellar synthesis, is significantly inhibited in ΔdegS mutants, whereas in response to the overexpression of cyaA/crp and rpoS in the ΔdegS strain, the motility and chemotaxis of the ΔdegS + cyaA/crp and ΔdegS + rpoS strains were partially restored compared with the ΔdegS strain. We further demonstrated that transcription levels of the flagellar regulatory gene flhF are regulated by DegS via the cAMP-CRP-RpoS signaling pathway. Overexpression of the flhF gene in the ΔdegS strain partially restored motility and chemotaxis. In addition, suckling mouse intestinal colonization experiments indicated that the ΔdegS and ΔrpoE strains were characterized by the poor colonization of mouse intestines, whereas colonization efficacy was restored in the ΔdegSΔrseA, ΔdegS + cyaA/crp, ΔdegS + rpoS, and ΔdegS + flhF strains. Collectively, our findings indicate that DegS regulates the motility and chemotaxis of V. cholerae via the cAMP-CRP-RpoS-FlhF pathway, thereby influencing the colonization of suckling mouse intestines.
Collapse
Affiliation(s)
- Mei Zou
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Kaiying Wang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Jiajun Zhao
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Huifang Lu
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Hui Yang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Meirong Huang
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
- Department of Blood Transfusion, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
| | - Lu Wang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Guangli Wang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Jian Huang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Xun Min
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
- School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| |
Collapse
|
19
|
Banse AV, VanBeuge S, Smith TJ, Logan SL, Guillemin K. Secreted Aeromonas GlcNAc binding protein GbpA stimulates epithelial cell proliferation in the zebrafish intestine. Gut Microbes 2023; 15:2183686. [PMID: 36859771 PMCID: PMC9988336 DOI: 10.1080/19490976.2023.2183686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/19/2022] [Accepted: 02/16/2023] [Indexed: 03/03/2023] Open
Abstract
In response to microbiota colonization, the intestinal epithelia of many animals exhibit increased rates of cell proliferation. We used gnotobiotic larval zebrafish to identify a secreted factor from the mutualist Aeromonas veronii that is sufficient to promote intestinal epithelial cell proliferation. This secreted A. veronii protein is a homologue of the Vibrio cholerae GlcNAc binding protein GbpA, which was identified as a chitin-binding colonization factor in mice. GbpA was subsequently shown to be a lytic polysaccharide monooxygenase (LPMO) that can degrade recalcitrant chitin. Our phenotypic characterization of gbpA deficient A. veronii found no alterations in these cells' biogeography in the zebrafish intestine and only a modest competitive disadvantage in chitin-binding and colonization fitness when competed against the wild-type strain. These results argue against the model of GbpA being a secreted adhesin that binds simultaneously to bacterial cells and GlcNAc, and instead suggests that GbpA is part of a bacterial GlcNAc utilization program. We show that the host proliferative response to GbpA occurs in the absence of bacteria upon exposure of germ-free zebrafish to preparations of native GbpA secreted from either A. veronii or V. cholerae or recombinant A. veronii GbpA. Furthermore, domain 1 of A. veronii GbpA, containing the predicted LPMO activity, is sufficient to stimulate intestinal epithelial proliferation. We propose that intestinal epithelial tissues upregulate their rates of renewal in response to secreted bacterial GbpA proteins as an adaptive strategy for coexisting with bacteria that can degrade glycan constituents of the protective intestinal lining.
Collapse
Affiliation(s)
- Allison V. Banse
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Stephanie VanBeuge
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - T. Jarrod Smith
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | | | - Karen Guillemin
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
- Humans and the Microbiome Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| |
Collapse
|
20
|
Gu D, Zhang Y, Wang K, Li M, Jiao X. Characterization of the RpoN regulon reveals the regulation of motility, T6SS2 and metabolism in Vibrio parahaemolyticus. Front Microbiol 2022; 13:1025960. [PMID: 36620062 PMCID: PMC9817140 DOI: 10.3389/fmicb.2022.1025960] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
Vibrio parahaemolyticus is a foodborne pathogen that can colonize the small intestine of the host and cause diarrhea. The alternative sigma factor RpoN plays a vital role in regulating motility, carbon utilization and affects host colonization in V. parahaemolyticus RIMD2210633. In this study, transcriptome and phenotypic analysis further expanded our understanding of the RpoN regulon in V. parahaemolyticus. A deletion mutant of rpoN (ΔrpoN) was subjected to RNA-seq for systemic identification of the RpoN-controlled genes. Compared with the wild-type (WT), 399 genes were differentially expressed in the ΔrpoN strain. Moreover, 264 genes were down-regulated in the ΔrpoN strain, including those associated with nitrogen utilization (VP0118), glutamine synthetase (VP0121), formate dehydrogenase (VP1511 and VP1513-VP1515), quorum sensing (opaR and luxZ), polar flagellar systems, and type VI secretion system 2 (T6SS2). Quantitative real-time reverse transcription PCR (qRT-PCR) and electrophoretic mobility shift assay (EMSA) further confirmed that RpoN could directly bind to the promoters of these genes associated with polar flagellar systems (flgB and fliE), lateral flagellar systems (flgB2 and lafA), T6SS2 (hcp2 and VPA1044) and glutamine synthetase (VP0121), and then positively regulate the expression of these systems. A RpoN-binding motif was identified in V. parahaemolyticus using the MEME suite and verified by the EMSA. Besides, the deletion of rpoN caused a significant decrease in hemolytic activity, adhesion, and cytotoxicity. Our results provide new cues to better understand the regulatory networks of RpoN protein to motility, T6SS2, and metabolism in V. parahaemolyticus.
Collapse
Affiliation(s)
- Dan Gu
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, China,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China
| | - Youkun Zhang
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, China,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China
| | - Kangru Wang
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, China,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China
| | - Mingzhu Li
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, China,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China
| | - Xinan Jiao
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, China,Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China,*Correspondence: Xinan Jiao,
| |
Collapse
|
21
|
Identification and Characterization of the Alternative σ 28 Factor in Treponema denticola. J Bacteriol 2022; 204:e0024822. [PMID: 36043861 PMCID: PMC9487585 DOI: 10.1128/jb.00248-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
FliA (also known as σ28), a member of the bacterial σ70 family of transcription factors, directs RNA polymerase to flagellar late (class 3) promoters and initiates transcription. FliA has been studied in several bacteria, yet its role in spirochetes has not been established. In this report, we identify and functionally characterize a FliA homolog (TDE2683) in the oral spirochete Treponema denticola. Computational, genetic, and biochemical analyses demonstrated that TDE2683 has a structure similar to that of the σ28 of Escherichia coli, binds to σ28-dependent promoters, and can functionally replace the σ28 of E. coli. However, unlike its counterparts from other bacteria, TDE2683 cannot be deleted, suggesting its essential role in the survival of T. denticola. In vitro site-directed mutagenesis revealed that E221 and V231, two conserved residues in the σ4 region of σ28, are indispensable for the binding activity of TDE2683 to the σ28-dependent promoter. We then mutated these two residues in T. denticola and found that the mutations impair the expression of flagellin and chemotaxis genes and bacterial motility as well. Cryo-electron tomography analysis further revealed that the mutations disrupt the flagellar symmetry (i.e., number and placement) of T. denticola. Collectively, these results indicate that TDE2683 is a σ28 transcription factor that regulates the class 3 gene expression and controls the flagellar symmetry of T. denticola. To the best of our knowledge, this is the first report establishing the functionality of FliA in spirochetes. IMPORTANCE Spirochetes are a group of medically important but understudied bacteria. One of the unique aspects of spirochetes is that they have periplasmic flagella (PF, also known as endoflagella) which give rise to their unique spiral shape and distinct swimming behaviors and play a critical role in the pathophysiology of spirochetes. PF are structurally similar to external flagella, but the underpinning mechanism that regulates PF biosynthesis and assembly remains largely unknown. By using the oral spirochete Treponema denticola as a model, this report provides several lines of evidence that FliA, a σ28 transcriptional factor, regulates the late flagellin gene (class 3) expression, PF assembly, and flagellar symmetry as well, which provides insights into flagellar regulation and opens an avenue to investigate the role of σ28 in spirochetes.
Collapse
|
22
|
Sequence Polymorphisms in Vibrio cholerae HapR Affect Biofilm Formation under Aerobic and Anaerobic Conditions. Appl Environ Microbiol 2022; 88:e0104422. [PMID: 35969071 PMCID: PMC9469714 DOI: 10.1128/aem.01044-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We investigated the influence of hapR sequence mutations on the biofilm formation of Vibrio cholerae. In this study, hapR sequences from 85 V. cholerae strains belonging to both pandemic and nonpandemic serogroup were investigated through phylogenetic and sequence analyses. Biofilm formation assays under aerobic and anaerobic conditions were also performed. Sequence variations include single point mutations and insertions/deletions (indels) leading to either truncated or frameshifted HapR. Population structure analysis revealed two major hapR haplogroups, hapR1 and hapR2. Phylogenetic reconstruction displayed a hypothetical ancestral hapR sequence located within the hapR1 haplogroup. Higher numbers of single nucleotide polymorphisms and genetic diversity indices were observed in hapR1, while indels occurred dominantly in hapR2. Aerobic conditions supported more robust biofilms compared to anaerobic conditions. Strains with frameshifted HapR produced the largest amount of biofilm under both oxygen conditions. Quantitative real-time PCR assay confirmed that strains with truncated and frameshifted HapR resulted in a nonfunctional regulator as exhibited by the significantly low hapA gene expression. The present study shows that HapR mutations had a strong influence on biofilm formation and that sequence polymorphisms leading to the disruption of DNA-binding sites or dimerization of the HapR will result in more-robust V. cholerae biofilms. IMPORTANCE Our study revealed an ancestral hapR sequence from a phylogenetic reconstruction that displayed the evolutionary lineage of the nonpandemic to the pandemic strains. Here, we established hapR1 and hapR2 as major hapR haplogroups. The association of the O1 and O139 serogroups with the hapR2 haplogroup demonstrated the distinction of hapR2 in causing cholera infection. Moreover, mutations in this regulator that could lead to the disruption of transcription factor-binding sites or dimerization of the HapR can significantly affect the biofilm formation of V. cholerae. These observations on the relationship of the hapR polymorphism and V. cholerae biofilm formation will provide additional considerations for future biofilm studies and insights into the epidemiology of the pathogen that could ultimately help in the surveillance and mitigation of future cholera disease outbreaks.
Collapse
|
23
|
Qi X, Xu X, Li H, Pan Y, Katharine Kraco E, Zheng J, Lin M, Jiang X. fliA, flrB, and fliR regulate adhesion by controlling the expression of critical virulence genes in Vibrio harveyi. Gene 2022; 839:146726. [PMID: 35835408 DOI: 10.1016/j.gene.2022.146726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 06/07/2022] [Accepted: 07/08/2022] [Indexed: 11/16/2022]
Abstract
Bacteria adhesion to fish mucus is a crucial virulence mechanism. As the initial step of bacterial infection, adhesion is impacted by bacterial motility and environmental conditions. However, its molecular mechanism is yet unclear. In this study, a significant decrease in gene expression of adhesion-deficient Vibrio harveyi was observed when the bacteria were subjected by Cu2+(50 mg/L), Pb2+(100 mg/L), Hg2+(25 mg/L), and Zn2+(50 mg/L). The genes fliA, fliR, and flrB were responsible for flagellation; being crucial for adhesion, these genes were identified and silenced via RNAi. After silencing of these genes by RNAi technology, the ability of adhesion, biofilm formation, motility, and flagella synthesis of V. harveyi were considerably reduced. Compared with the control group, it was observed that the expression levels of fliS, fliD, flgH, and flrC were significant down-regulated in fliR-RNAi, flrB-RNAi, and fliA-RNAi. This data indicates that the expression levels of most virulence genes are affected by fliA, fliR, and flrB. Also, the expression of fliA, fliR, and flrB can be influenced by the salinity, temperature, and pH. The results show that: (1) fliA, fliR, and flrB have important roles in the adhesion of V. harveyi; (2) fliA, fliR, and flrB can regulate bacterial adhesion by affecting its motility, and biofilm formation; (3) fliA, fliR, and flrB can regulate adhesion ability of V. harveyi in different environments.
Collapse
Affiliation(s)
- Xin Qi
- State Key Laboratory of Large Yellow Croaker Breeding, Fujian Fuding Seagull Fishing Food Co. Ltd., Ningde 352103, China; Fisheries College, Jimei University, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen 361021, Fujian, China
| | - Xiaojin Xu
- State Key Laboratory of Large Yellow Croaker Breeding, Fujian Fuding Seagull Fishing Food Co. Ltd., Ningde 352103, China; Fisheries College, Jimei University, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen 361021, Fujian, China; Fujian Province Key Laboratory of Special Aquatic Formula Feed (Fujian Tianma Science and Technology Group Co., Ltd., China; School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 East Greenfield Avenue, Milwaukee, WI 53204, USA.
| | - Huiyao Li
- State Key Laboratory of Large Yellow Croaker Breeding, Fujian Fuding Seagull Fishing Food Co. Ltd., Ningde 352103, China; Fisheries Research Institute of Fujian, Xiamen 361013, China
| | - Ying Pan
- State Key Laboratory of Large Yellow Croaker Breeding, Fujian Fuding Seagull Fishing Food Co. Ltd., Ningde 352103, China
| | | | - Jiang Zheng
- Fisheries College, Jimei University, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen 361021, Fujian, China
| | - Mao Lin
- Fisheries College, Jimei University, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen 361021, Fujian, China
| | - Xinglong Jiang
- State Key Laboratory of Large Yellow Croaker Breeding, Fujian Fuding Seagull Fishing Food Co. Ltd., Ningde 352103, China; Fisheries College, Jimei University, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen 361021, Fujian, China.
| |
Collapse
|
24
|
AroC, a Chorismate Synthase, is Required for the Formation of Edwardsiella tarda biofilms. Microbes Infect 2022; 24:104955. [PMID: 35272020 DOI: 10.1016/j.micinf.2022.104955] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 01/27/2022] [Accepted: 02/23/2022] [Indexed: 11/19/2022]
Abstract
Biofilms contribute to the resistance of Edwardsiella tarda to antibiotics and host immunity. AroC in the shikimate pathway produces chorismate to synthesize crucial intermediates such as indole. In this study, the differences between biofilms produced by aroC mutants (△aroC), wild-type (WT) strains, and △aroC complementary strains (C△aroC) were detected both in vitro with 96-well plates, tubes, or coverslips and in vivo using a mouse model of subcutaneous implants. When examining potential mechanisms, we found that the diameters of the movement rings in soft agar plates and the flagellar sizes and numbers determined by silver staining were all lower for △aroC than for WT and C△aroC. Moreover, qRT-PCR showed that the transcription levels of flagellar synthesis genes, fliA and fliC, were reduced in △aroC. AroC, FliC, or FliA may accompany the motility of △aroC strains. In addition, compared with the WT and C△aroC, the amounts of indole in △aroC were significantly decreased. Notably, the formation of biofilms by these strains could be promoted by exogenous indole. Therefore, the aroC gene could affect the biofilm formation of E. tarda concerning its impact on flagella and indole.
Collapse
|
25
|
Hoque MM, Noorian P, Espinoza-Vergara G, Manuneedhi Cholan P, Kim M, Rahman MH, Labbate M, Rice SA, Pernice M, Oehlers SH, McDougald D. Adaptation to an amoeba host drives selection of virulence-associated traits in Vibrio cholerae. THE ISME JOURNAL 2022; 16:856-867. [PMID: 34654895 PMCID: PMC8857207 DOI: 10.1038/s41396-021-01134-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 09/20/2021] [Accepted: 09/29/2021] [Indexed: 12/02/2022]
Abstract
Predation by heterotrophic protists drives the emergence of adaptive traits in bacteria, and often these traits lead to altered interactions with hosts and persistence in the environment. Here we studied adaptation of the cholera pathogen, Vibrio cholerae during long-term co-incubation with the protist host, Acanthamoeba castellanii. We determined phenotypic and genotypic changes associated with long-term intra-amoebal host adaptation and how this impacts pathogen survival and fitness. We showed that adaptation to the amoeba host leads to temporal changes in multiple phenotypic traits in V. cholerae that facilitate increased survival and competitive fitness in amoeba. Genome sequencing and mutational analysis revealed that these altered lifestyles were linked to non-synonymous mutations in conserved regions of the flagellar transcriptional regulator, flrA. Additionally, the mutations resulted in enhanced colonisation in zebrafish, establishing a link between adaptation of V. cholerae to amoeba predation and enhanced environmental persistence. Our results show that pressure imposed by amoeba on V. cholerae selects for flrA mutations that serves as a key driver for adaptation. Importantly, this study provides evidence that adaptive traits that evolve in pathogens in response to environmental predatory pressure impact the colonisation of eukaryotic organisms by these pathogens.
Collapse
Affiliation(s)
- M. Mozammel Hoque
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia
| | - Parisa Noorian
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia
| | - Gustavo Espinoza-Vergara
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia
| | - Pradeep Manuneedhi Cholan
- grid.1013.30000 0004 1936 834XTuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW Australia ,grid.1013.30000 0004 1936 834XFaculty of Medicine and Health & Marie Bashir Institute, The University of Sydney, Camperdown, NSW Australia
| | - Mikael Kim
- grid.117476.20000 0004 1936 7611Climate Change Cluster, University of Technology Sydney, Sydney, NSW Australia
| | - Md Hafizur Rahman
- grid.117476.20000 0004 1936 7611School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW Australia
| | - Maurizio Labbate
- grid.117476.20000 0004 1936 7611School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW Australia
| | - Scott A. Rice
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia ,grid.59025.3b0000 0001 2224 0361Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Mathieu Pernice
- grid.117476.20000 0004 1936 7611Climate Change Cluster, University of Technology Sydney, Sydney, NSW Australia
| | - Stefan H. Oehlers
- grid.1013.30000 0004 1936 834XTuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW Australia ,grid.1013.30000 0004 1936 834XFaculty of Medicine and Health & Marie Bashir Institute, The University of Sydney, Camperdown, NSW Australia
| | - Diane McDougald
- grid.117476.20000 0004 1936 7611The iThree Institute, University of Technology Sydney, Sydney, NSW Australia ,grid.59025.3b0000 0001 2224 0361Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| |
Collapse
|
26
|
Zheng H, Huang Y, Liu P, Yan L, Zhou Y, Yang C, Wu Y, Qin J, Guo Y, Pei X, Guo Y, Cui Y, Liang W. Population genomics of the food-borne pathogen Vibrio fluvialis reveals lineage associated pathogenicity-related genetic elements. Microb Genom 2022; 8. [PMID: 35212619 PMCID: PMC8942032 DOI: 10.1099/mgen.0.000769] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vibrio fluvialis is a food-borne pathogen with epidemic potential that causes cholera-like acute gastroenteritis and sometimes extraintestinal infections in humans. However, research on its genetic diversity and pathogenicity-related genetic elements based on whole genome sequences is lacking. In this study, we collected and sequenced 130 strains of V. fluvialis from 14 provinces of China, and also determined the susceptibility of 35 of the strains to 30 different antibiotics. Combined with 52 publicly available V. fluvialis genomes, we inferred the population structure and investigated the characteristics of pathogenicity-related factors. The V. fluvialis strains exhibited high levels of homologous recombination and were assigned to two major populations, VflPop1 and VflPop2, according to the different compositions of their gene pools. VflPop2 was subdivided into groups 2.1 and 2.2. Except for VflPop2.2, which consisted only of Asian strains, the strains in VflPop1 and VflPop2.1 were distributed in the Americas, Asia and Europe. Analysis of the pathogenicity potential of V. fluvialis showed that most of the identified virulence-related genes or gene clusters showed high prevalence in V. fluvialis, except for three mobile genetic elements: pBD146, ICEVflInd1 and MGIVflInd1, which were scattered in only a few strains. A total of 21 antimicrobial resistance genes were identified in the genomes of the 182 strains analysed in this study, and 19 (90%) of them were exclusively present in VflPop2. Notably, the tetracycline resistance-related gene tet(35) was present in 150 (95%) of the strains in VflPop2, and in only one (4%) strain in VflPop1, indicating it was population-specific. In total, 91% of the 35 selected strains showed resistance to cefazolin, indicating V. fluvialis has a high resistance rate to cefazolin. Among the 15 genomes that carried the previously reported drug resistance-related plasmid pBD146, 11 (73%) showed resistance to trimethoprim-sulfamethoxazole, which we inferred was related to the presence of the dfr6 gene in the plasmid. On the basis of the population genomics analysis, the genetic diversity, population structure and distribution of pathogenicity-related factors of V. fluvialis were delineated in this study. The results will provide further clues regarding the evolution and pathogenic mechanisms of V. fluvialis, and improve our knowledge for the prevention and control of this pathogen.
Collapse
Affiliation(s)
- Hongyuan Zheng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Yuanming Huang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China
| | - Ping Liu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China
| | - Lin Yan
- National Center for Food Safety Risk Assessment, Beijing 100022, PR China
| | - Yanyan Zhou
- Center of Clinical Laboratory, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, PR China
| | - Chao Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Yarong Wu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Jingliang Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Yan Guo
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Xiaoyan Pei
- National Center for Food Safety Risk Assessment, Beijing 100022, PR China
| | - Yunchang Guo
- National Center for Food Safety Risk Assessment, Beijing 100022, PR China
| | - Yujun Cui
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Weili Liang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China
| |
Collapse
|
27
|
Homma M, Kojima S. Roles of the second messenger c‐di‐GMP in bacteria: Focusing on the topics of flagellar regulation and
Vibrio
spp. Genes Cells 2022; 27:157-172. [PMID: 35073606 PMCID: PMC9303241 DOI: 10.1111/gtc.12921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/28/2021] [Accepted: 01/10/2022] [Indexed: 11/30/2022]
Abstract
Typical second messengers include cyclic AMP (cAMP), cyclic GMP (cGMP), and inositol phosphate. In bacteria, cyclic diguanylate (c‐di‐GMP), which is not used in animals, is widely used as a second messenger for environmental responses. Initially found as a regulator of cellulose synthesis, this small molecule is known to be widely present in bacteria. A wide variety of synthesis and degradation enzymes for c‐di‐GMP exist, and the activities of effector proteins are regulated by changing the cellular c‐di‐GMP concentration in response to the environment. It has been shown well that c‐di‐GMP plays an essential role in pathogenic cycle and is involved in flagellar motility in Vibrio cholerae. In this review, we aim to explain the direct or indirect regulatory mechanisms of c‐di‐GMP in bacteria, focusing on the study of c‐di‐GMP in Vibrio spp. and in flagella, which are our research subjects.
Collapse
Affiliation(s)
- Michio Homma
- Division of Biological Science Graduate School of Science Nagoya University Nagoya Japan
| | - Seiji Kojima
- Division of Biological Science Graduate School of Science Nagoya University Nagoya Japan
| |
Collapse
|
28
|
Li Y, Yan J, Guo X, Wang X, Liu F, Cao B. The global regulators ArcA and CytR collaboratively modulate Vibrio cholerae motility. BMC Microbiol 2022; 22:22. [PMID: 35021992 PMCID: PMC8753867 DOI: 10.1186/s12866-022-02435-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 01/05/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Vibrio cholerae, a Gram-negative bacterium, is highly motile owing to the presence of a single polar flagellum. The global anaerobiosis response regulator, ArcA regulates the expression of virulence factors and enhance biofilm formation in V. cholerae. However, the function of ArcA for the motility of V. cholerae is yet to be elucidated. CytR, which represses nucleoside uptake and catabolism, is known to play a chief role in V. cholerae pathogenesis and flagellar synthesis but the mechanism that CytR influences motility is unclear.
Results
In this study, we found that the ΔarcA mutant strain exhibited higher motility than the WT strain due to ArcA directly repressed flrA expression. We further discovered that CytR directly enhanced fliK expression, which explained why the ΔcytR mutant strain was retarded in motility. On the other hand, cytR was a direct ArcA target and cytR expression was directly repressed by ArcA. As expected, cytR expression was down-regulated.
Conclusions
Overall, ArcA plays a critical role in V. cholerae motility by regulating flrA expression directly and fliK indirectly in the manner of cytR.
Collapse
|
29
|
Ataeian M, Vadlamani A, Haines M, Mosier D, Dong X, Kleiner M, Strous M, Hawley AK. Proteome and strain analysis of cyanobacterium Candidatus "Phormidium alkaliphilum" reveals traits for success in biotechnology. iScience 2021; 24:103405. [PMID: 34877483 PMCID: PMC8633866 DOI: 10.1016/j.isci.2021.103405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/27/2021] [Accepted: 11/03/2021] [Indexed: 11/18/2022] Open
Abstract
Cyanobacteria encompass a diverse group of photoautotrophic bacteria with important roles in nature and biotechnology. Here we characterized Candidatus “Phormidium alkaliphilum,” an abundant member in alkaline soda lake microbial communities globally. The complete, circular whole-genome sequence of Ca. “P. alkaliphilum” was obtained using combined Nanopore and Illumina sequencing of a Ca. “P. alkaliphilum” consortium. Strain-level diversity of Ca. “P. alkaliphilum” was shown to contribute to photobioreactor robustness under different operational conditions. Comparative genomics of closely related species showed that adaptation to high pH was not attributed to specific genes. Proteomics at high and low pH showed only minimal changes in gene expression, but higher productivity in high pH. Diverse photosystem antennae proteins, and high-affinity terminal oxidase, compared with other soda lake cyanobacteria, appear to contribute to the success of Ca. “P. alkaliphilum” in photobioreactors and biotechnology applications. Closed genome of the cyanobacteria Ca. P. alkaliphilum from high-pH photobioreactor Genetic factors lead this Phormidium to outcompete other cyanobacteria in photobioreactor Adaptation to high pH and alkalinity is not linked to specific genes Strain-level diversity contributes Ca. P. alkaliphilum success in changing conditions
Collapse
Affiliation(s)
- Maryam Ataeian
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | | | - Marianne Haines
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Damon Mosier
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Xiaoli Dong
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Marc Strous
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Alyse K. Hawley
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
- School of Engineering, University of British Columbia Okanagan, Kelowna, BC, Canada
- Corresponding author
| |
Collapse
|
30
|
Homma M, Nishikino T, Kojima S. Achievements in bacterial flagellar research with focus on Vibrio species. Microbiol Immunol 2021; 66:75-95. [PMID: 34842307 DOI: 10.1111/1348-0421.12954] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 12/01/2022]
Abstract
In 1980's, the most genes involved in the bacterial flagellar function and formation had been isolated though many of their functions or roles were not clarified. Bacterial flagella are the primary locomotive organ and are not necessary for growing in vitro but are probably essential for living in natural condition and are involved in the pathogenicity. In vitro, the flagella-deficient strains can grow at rates similar to wild-type strains. More than 50 genes are responsible for flagellar function, and the flagellum is constructed by more than 20 structural proteins. The maintenance cost of flagellum is high as several genes are required for its development. The fact that it evolved as a motor organ even with such the high cost shows that the motility is indispensable to survive under the harsh environment of Earth. In this review, we focus on flagella-related research conducted by the authors for about 40 years and flagellar research focused on Vibrio spp. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University
| | | | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University
| |
Collapse
|
31
|
Guo S, Zahiri H, Stevens C, Spaanderman DC, Milroy LG, Ottmann C, Brunsveld L, Voets IK, Davies PL. Molecular basis for inhibition of adhesin-mediated bacterial-host interactions through a peptide-binding domain. Cell Rep 2021; 37:110002. [PMID: 34788627 DOI: 10.1016/j.celrep.2021.110002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 08/26/2021] [Accepted: 10/25/2021] [Indexed: 12/17/2022] Open
Abstract
Infections typically begin with pathogens adhering to host cells. For bacteria, this adhesion can occur through specific ligand-binding domains. We identify a 20-kDa peptide-binding domain (PBD) in a 1.5-MDa RTX adhesin of a Gram-negative marine bacterium that colonizes diatoms. The crystal structure of this Ca2+-dependent PBD suggests that it may bind the C termini of host cell-surface proteins. A systematic peptide library analysis reveals an optimal tripeptide sequence with 30-nM affinity for the PBD, and X-ray crystallography details its peptide-protein interactions. Binding of the PBD to the diatom partner of the bacteria can be inhibited or competed away by the peptide, providing a molecular basis for inhibiting bacterium-host interactions. We further show that this PBD is found in other bacteria, including human pathogens such as Vibrio cholerae and Aeromonas veronii. Here, we produce the PBD ortholog from A. veronii and demonstrate, using the same peptide inhibitor, how pathogens may be prevented from adhering to their hosts.
Collapse
Affiliation(s)
- Shuaiqi Guo
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada; Laboratory of Self-Organizing Soft Matter, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands; Laboratory of Chemical Biology, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands
| | - Hossein Zahiri
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Corey Stevens
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Daniel C Spaanderman
- Laboratory of Chemical Biology, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands; Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands
| | - Lech-Gustav Milroy
- Laboratory of Chemical Biology, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands
| | - Christian Ottmann
- Laboratory of Chemical Biology, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands
| | - Luc Brunsveld
- Laboratory of Chemical Biology, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands
| | - Ilja K Voets
- Laboratory of Self-Organizing Soft Matter, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands; Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology PO Box 513, 5600 MB Eindhoven, the Netherlands
| | - Peter L Davies
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada.
| |
Collapse
|
32
|
Gut Microbiota and Development of Vibrio cholerae-Specific Long-Term Memory B Cells in Adults after Whole-Cell Killed Oral Cholera Vaccine. Infect Immun 2021; 89:e0021721. [PMID: 34228490 PMCID: PMC8370679 DOI: 10.1128/iai.00217-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cholera is a diarrheal disease caused by Vibrio cholerae that continues to be a major public health concern in populations without access to safe water. IgG- and IgA-secreting memory B cells (MBC) targeting the V. cholerae O-specific polysaccharide (OSP) correlate with protection from infection in persons exposed to V. cholerae and may be a major determinant of long-term protection against cholera. Shanchol, a widely used oral cholera vaccine (OCV), stimulates OSP MBC responses in only some people after vaccination, and the gut microbiota is a possible determinant of variable immune responses observed after OCV. Using 16S rRNA sequencing of feces from the time of vaccination, we compared the gut microbiota among adults with and without MBC responses to OCV. Gut microbial diversity measures were not associated with MBC isotype or OSP-specific responses, but individuals with a higher abundance of Clostridiales and lower abundance of Enterobacterales were more likely to develop an MBC response. We applied protein-normalized fecal supernatants of high and low MBC responders to THP-1-derived human macrophages to investigate the effect of microbial factors at the time of vaccination. Feces from individuals with higher MBC responses induced significantly different IL-1β and IL-6 levels than individuals with lower responses, indicating that the gut microbiota at the time of vaccination may "prime" the mucosal immune response to vaccine antigens. Our results suggest the gut microbiota could impact immune responses to OCVs, and further study of microbial metabolites as potential vaccine adjuvants is warranted.
Collapse
|
33
|
Das S, Chourashi R, Mukherjee P, Gope A, Koley H, Dutta M, Mukhopadhyay AK, Okamoto K, Chatterjee NS. Multifunctional transcription factor CytR of Vibrio cholerae is important for pathogenesis. MICROBIOLOGY-SGM 2021; 166:1136-1148. [PMID: 33150864 DOI: 10.1099/mic.0.000949] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Vibrio cholerae, the Gram-negative facultative pathogen, resides in the aquatic environment and infects humans and causes diarrhoeagenic cholera. Although the environment differs drastically, V. cholerae thrives in both of these conditions aptly and chitinases play a vital role in their persistence and nutrient acquisition. Chitinases also play a role in V. cholerae pathogenesis. Chitinases and its downstream chitin utilization genes are regulated by sensor histidine kinase ChiS, which also plays a significant role in pathogenesis. Recent exploration suggests that CytR, a transcription factor of the LacI family in V. cholerae, also regulates chitinase secretion in environmental conditions. Since chitinases and chitinase regulator ChiS is involved in pathogenesis, CytR might also play a significant role in pathogenicity. However, the role of CytR in pathogenesis is yet to be known. This study explores the regulation of CytR on the activation of ChiS in the presence of mucin and its role in pathogenesis. Therefore, we created a CytR isogenic mutant strain of V. cholerae (CytR¯) and found considerably less β-hexosaminidase enzyme production, which is an indicator of ChiS activity. The CytR¯ strain greatly reduced the expression of chitinases chiA1 and chiA2 in mucin-supplemented media. Electron microscopy showed that the CytR¯ strain was aflagellate. The expression of flagellar-synthesis regulatory genes flrB, flrC and class III flagellar-synthesis genes were reduced in the CytR¯ strain. The isogenic CytR mutant showed less growth compared to the wild-type in mucin-supplemented media as well as demonstrated highly retarded motility and reduced mucin-layer penetration. The CytR mutant revealed decreased adherence to the HT-29 cell line. In animal models, reduced fluid accumulation and colonization were observed during infection with the CytR¯ strain due to reduced expression of ctxB, toxT and tcpA. Collectively these data suggest that CytR plays an important role in V. cholerae pathogenesis.
Collapse
Affiliation(s)
- Suman Das
- Division of Biochemistry, ICMR - National Institute of Cholera and Enteric Diseases, Kolkata-700010, India
| | - Rhishita Chourashi
- Division of Biochemistry, ICMR - National Institute of Cholera and Enteric Diseases, Kolkata-700010, India
| | - Priyadarshini Mukherjee
- Division of Bacteriology, ICMR - National Institute of Cholera and Enteric Diseases, Kolkata-700010, India
| | - Animesh Gope
- Division of Clinical Medicine, ICMR - National Institute of Cholera and Enteric Diseases, Kolkata-700010, India
| | - Hemanta Koley
- Division of Bacteriology, ICMR - National Institute of Cholera and Enteric Diseases, Kolkata-700010, India
| | - Moumita Dutta
- Division of Electron Microscopy, ICMR - National Institute of Cholera and Enteric Diseases, Kolkata-700010, India
| | - Asish K Mukhopadhyay
- Division of Bacteriology, ICMR - National Institute of Cholera and Enteric Diseases, Kolkata-700010, India
| | - Keinosuke Okamoto
- Collaborative Research Center of Okayama University for Infectious Diseases at NICED, Kolkata, India
| | - Nabendu Sekhar Chatterjee
- Division of Biochemistry, ICMR - National Institute of Cholera and Enteric Diseases, Kolkata-700010, India
| |
Collapse
|
34
|
The polar flagellar transcriptional regulatory network in Vibrio campbellii deviates from canonical Vibrio species. J Bacteriol 2021; 203:e0027621. [PMID: 34339299 DOI: 10.1128/jb.00276-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Swimming motility is a critical virulence factor in pathogenesis for numerous Vibrio species. Vibrio campbellii DS40M4 is a wild isolate that has been recently established as a highly tractable model strain for bacterial genetics studies. We sought to exploit the tractability and relevance of this strain for characterization of flagellar gene regulation in V. campbellii. Using comparative genomics, we identified homologs of V. campbellii flagellar and chemotaxis genes conserved in other members of the Vibrionaceae and determined the transcriptional profile of these loci using differential RNA-seq. We systematically deleted all 63 predicted flagellar and chemotaxis genes in V. campbellii and examined their effects on motility and flagellum production. We specifically focused on the core regulators of the flagellar hierarchy established in other vibrios: RpoN (σ54), FlrA, FlrC, and FliA. Our results show that V. campbellii transcription of flagellar and chemotaxis genes is governed by a multi-tiered regulatory hierarchy similar to other motile Vibrio species. However, there are several critical differences in V. campbellii: (i) the σ54-dependent regulator FlrA is dispensable for motility, (ii) the flgA, fliEFGHIJ, flrA, and flrBC operons do not require σ54 for expression, and (iii) FlrA and FlrC co-regulate class II genes. Our model proposes that the V. campbellii flagellar transcriptional hierarchy has three classes of genes, in contrast to the four-class hierarchy in Vibrio cholerae. Our genetic and phenotypic dissection of the V. campbellii flagellar regulatory network highlights the differences that have evolved in flagellar regulation across the Vibrionaceae. Importance Vibrio campbellii is a Gram-negative bacterium that is free-living and ubiquitous in marine environments and is an important global pathogen of fish and shellfish. Disruption of the flagellar motor significantly decreases host mortality of V. campbellii, suggesting that motility is a key factor in pathogenesis. Using this model organism, we identified >60 genes that encode proteins with predicted structural, mechanical, or regulatory roles in function of the single polar flagellum in V. campbellii. We systematically tested strains containing single deletions of each gene to determine the impact on motility and flagellum production. Our studies have uncovered differences in the regulatory network and function of several genes in V. campbellii as compared to established systems in Vibrio cholerae and Vibrio parahaemolyticus.
Collapse
|
35
|
Zhang N, Zhang S, Ren W, Gong X, Long H, Zhang X, Cai X, Huang A, Xie Z. Roles of rpoN in biofilm formation of Vibrio alginolyticus HN08155 at different cell densities. Microbiol Res 2021; 247:126728. [PMID: 33684638 DOI: 10.1016/j.micres.2021.126728] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 01/14/2021] [Accepted: 02/13/2021] [Indexed: 11/18/2022]
Abstract
RpoN (δ54) as a global regulator controls crucialvirulence-associated phenotype, which can regulate flagellum and exopolysaccharides (EPS) during pathogenic biofilm formation. However, the knowledge of the roles of rpoN in biofilm formation of V. alginolyticus is limited, especially at different cell densities. Herein, deletion mutant strain ΔrpoN, complementary strain ΔrpoN-C and negative control strain ΔrpoN-Z were constructed to investigate the effects of rpoN on biofilm formation of V. alginolyticus HN08155 based on flagellum and EPS at different cell density conditions. The results showed that all of strains can form biofilm, and biofilms of strains with rpoN were formed at low cell density (LCD) and detached at high cell density (HCD), while those of ΔrpoN and ΔrpoN-Z were absent at LCD and accumulated excessively with a spotty pellicle at HCD without detaching. The EPS contents of strains with rpoN was greater than that of ΔrpoN and ΔrpoN-Z at LCD, while the opposite trends were observed at HCD. The expression levels of rpoN were quantified, which were consistent with the trend of biofilm formation. It's worth noting that absence of rpoN resulted in the failure of biofilm detachment, lacking of flagellum and decreasing motility, indicating that rpoN was not necessary for biofilm formation, but it was essential for biofilm detachment.
Collapse
Affiliation(s)
- Na Zhang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Shun Zhang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Wei Ren
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Xiaoxiao Gong
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Hao Long
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China
| | - Xiang Zhang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Xiaoni Cai
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Aiyou Huang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China
| | - Zhenyu Xie
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, 570228, Hainan Province, China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Hainan University, Haikou, 570228, Hainan Province, China; College of Marine Sciences, Hainan University, Haikou, 570228, Hainan Province, China.
| |
Collapse
|
36
|
Abstract
Vibrio cholerae, a Gram-negative bacterium, is a natural inhabitant of the aqueous environment. However, once ingested, this bacterium can colonize the human host and cause the disease cholera. CsrA is a posttranscriptional global regulator in Vibrio cholerae. Although CsrA is critical for V. cholerae survival within the mammalian host, the regulatory targets of CsrA remain mostly unknown. To identify pathways controlled by CsrA, RNA-seq transcriptome analysis was carried out by comparing the wild type and the csrA mutant grown to early exponential, mid-exponential, and stationary phases of growth. This enabled us to identify the global effects of CsrA-mediated regulation throughout the V. cholerae growth cycle. We found that CsrA regulates 22% of the V. cholerae transcriptome, with significant regulation within the gene ontology (GO) processes that involve amino acid transport and metabolism, central carbon metabolism, lipid metabolism, iron uptake, and flagellum-dependent motility. Through CsrA-RNA coimmunoprecipitation experiments, we found that CsrA binds to multiple mRNAs that encode regulatory proteins. These include transcripts encoding the major sigma factors RpoS and RpoE, which may explain how CsrA regulation affects such a large proportion of the V. cholerae transcriptome. Other direct targets include flrC, encoding a central regulator in flagellar gene expression, and aphA, encoding the virulence gene transcription factor AphA. We found that CsrA binds to the aphA mRNA both in vivo and in vitro, and CsrA significantly increases AphA protein synthesis. The increase in AphA was due to increased translation, not transcription, in the presence of CsrA, consistent with CsrA binding to the aphA transcript and enhancing its translation. CsrA is required for the virulence of V. cholerae and this study illustrates the central role of CsrA in virulence gene regulation.
Collapse
|
37
|
Nishikino T, Kojima S, Homma M. [Flagellar related genes and functions in Vibrio]. Nihon Saikingaku Zasshi 2021; 75:195-214. [PMID: 33390367 DOI: 10.3412/jsb.75.195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Bacteria can move or swim by flagella. On the other hand, the motile ability is not necessary to live at all. In laboratory, the flagella-deficient strains can grow just like the wild-type strains. The flagellum is assembled from more than 20 structural proteins and there are more than 50 genes including the structural genes to regulate or support the flagellar formation. The cost to construct the flagellum is so expensive. The fact that it evolved as a motor organ means even at such the large cost shows that the flagellum is essential for survival in natural condition. In this review, we would like to focus on the flagella-related researches conducted by the authors and the flagellar research on Vibrio spp.
Collapse
Affiliation(s)
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University
| |
Collapse
|
38
|
Sofia MK, Dziejman M. DksA coordinates bile-mediated regulation of virulence-associated phenotypes in type three secretion system-positive Vibrio cholerae. MICROBIOLOGY-SGM 2020; 167. [PMID: 33332258 DOI: 10.1099/mic.0.001006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In order to cause disease, pathogenic strains of Vibrio cholerae rely on intricate regulatory networks to orchestrate the transition between their native aquatic environment and the human host. For example, bacteria in a nutrient-starved environment undergo a metabolic shift called the stringent response, which is mediated by the alarmone ppGpp and an RNA-polymerase binding transcriptional factor, DksA. In O1 serogroup strains of V. cholerae, which use the toxin co-regulated pilus (TCP) and cholera toxin (CT) as primary virulence factors, DksA was reported to have additional functions as a mediator of virulence gene expression. However, little is known about the regulatory networks coordinating virulence phenotypes in pathogenic strains that use TCP/CT-independent virulence mechanisms. We therefore investigated whether functions of DksA outside of the stringent response are conserved in type three secretion system (T3SS)-positive V. cholerae. In using the T3SS-positive clinically isolated O39 serogroup strain AM-19226, we observed an increase in dksA expression in the presence of bile at 37 °C. However, DksA was not required for wild-type levels of T3SS structural gene expression, or for colonization in vivo. Rather, data indicate that DksA positively regulates the expression of master regulators in the motility hierarchy. Interestingly, the ΔdksA strain forms a less robust biofilm than the WT parent strain at both 30 and 37 °C. We also found that DksA regulates the expression of hapR, encoding a major regulator of biofilm formation and protease expression. Athough DksA does not appear to modulate T3SS virulence factor expression, its activity is integrated into existing regulatory networks governing virulence-related phenotypes. Strain variations therefore may take advantage of conserved ancestral proteins to expand regulons responding to in vivo signals and thus coordinate multiple phenotypes important for infection.
Collapse
Affiliation(s)
- Madeline K Sofia
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave., Rochester, NY 14642, USA
| | - Michelle Dziejman
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave., Rochester, NY 14642, USA
| |
Collapse
|
39
|
Chakraborty S, Biswas M, Dey S, Agarwal S, Chakrabortty T, Ghosh B, Dasgupta J. The heptameric structure of the flagellar regulatory protein FlrC is indispensable for ATPase activity and disassembled by cyclic-di-GMP. J Biol Chem 2020; 295:16960-16974. [PMID: 32998953 PMCID: PMC7863884 DOI: 10.1074/jbc.ra120.014083] [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: 05/29/2020] [Revised: 09/26/2020] [Indexed: 11/06/2022] Open
Abstract
The bacterial enhancer-binding protein (bEBP) FlrC, controls motility and colonization of Vibrio cholerae by regulating the transcription of class-III flagellar genes in σ54-dependent manner. However, the mechanism by which FlrC regulates transcription is not fully elucidated. Although, most bEBPs require nucleotides to stimulate the oligomerization necessary for function, our previous study showed that the central domain of FlrC (FlrCC) forms heptamer in a nucleotide-independent manner. Furthermore, heptameric FlrCC binds ATP in "cis-mediated" style without any contribution from sensor I motif 285REDXXYR291 of the trans protomer. This atypical ATP binding raises the question of whether heptamerization of FlrC is solely required for transcription regulation, or if it is also critical for ATPase activity. ATPase assays and size exclusion chromatography of the trans-variants FlrCC-Y290A and FlrCC-R291A showed destabilization of heptameric assembly with concomitant abrogation of ATPase activity. Crystal structures showed that in the cis-variant FlrCC-R349A drastic shift of Walker A encroached ATP-binding site, whereas the site remained occupied by ADP in FlrCC-Y290A. We postulated that FlrCC heptamerizes through concentration-dependent cooperativity for maximal ATPase activity and upon heptamerization, packing of trans-acting Tyr290 against cis-acting Arg349 compels Arg349 to maintain proper conformation of Walker A. Finally, a Trp quenching study revealed binding of cyclic-di-GMP with FlrCC Excess cyclic-di-GMP repressed ATPase activity of FlrCC through destabilization of heptameric assembly, especially at low concentration of protein. Systematic phylogenetic analysis allowed us to propose similar regulatory mechanisms for FlrCs of several Vibrio species and a set of monotrichous Gram-negative bacteria.
Collapse
Affiliation(s)
| | - Maitree Biswas
- Department of Biotechnology, St. Xavier's College, Kolkata, India
| | - Sanjay Dey
- Department of Biotechnology, St. Xavier's College, Kolkata, India
| | | | | | - Biplab Ghosh
- High Pressure & Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India
| | - Jhimli Dasgupta
- Department of Biotechnology, St. Xavier's College, Kolkata, India.
| |
Collapse
|
40
|
Orellana CA, Zaragoza NE, Licona-Cassani C, Palfreyman RW, Cowie N, Moonen G, Moutafis G, Power J, Nielsen LK, Marcellin E. Time-course transcriptomics reveals that amino acids catabolism plays a key role in toxinogenesis and morphology in Clostridium tetani. ACTA ACUST UNITED AC 2020; 47:1059-1073. [DOI: 10.1007/s10295-020-02330-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 11/02/2020] [Indexed: 10/23/2022]
Abstract
Abstract
Tetanus is a fatal disease caused by Clostridium tetani infections. To prevent infections, a toxoid vaccine, developed almost a century ago, is routinely used in humans and animals. The vaccine is listed in the World Health Organisation list of Essential Medicines and can be produced and administered very cheaply in the developing world for less than one US Dollar per dose. Recent developments in both analytical tools and frameworks for systems biology provide industry with an opportunity to gain a deeper understanding of the parameters that determine C. tetani virulence and physiological behaviour in bioreactors. Here, we compared a traditional fermentation process with a fermentation medium supplemented with five heavily consumed amino acids. The experiment demonstrated that amino acid catabolism plays a key role in the virulence of C. tetani. The addition of the five amino acids favoured growth, decreased toxin production and changed C. tetani morphology. Using time-course transcriptomics, we created a “fermentation map”, which shows that the tetanus toxin transcriptional regulator BotR, P21 and the tetanus toxin gene was downregulated. Moreover, this in-depth analysis revealed potential genes that might be involved in C. tetani virulence regulation. We observed differential expression of genes related to cell separation, surface/cell adhesion, pyrimidine biosynthesis and salvage, flagellar motility, and prophage genes. Overall, the fermentation map shows that, mediated by free amino acid concentrations, virulence in C. tetani is regulated at the transcriptional level and affects a plethora of metabolic functions.
Collapse
Affiliation(s)
- Camila A Orellana
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.7870.8 0000 0001 2157 0406 Department of Chemical and Bioprocess Engineering, School of Engineering Pontificia Universidad Católica de Chile Santiago Chile
| | - Nicolas E Zaragoza
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
| | - Cuauhtemoc Licona-Cassani
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.419886.a 0000 0001 2203 4701 Centro de Biotecnología FEMSA Tecnológico de Monterrey Nuevo León Mexico
| | - Robin W Palfreyman
- grid.1003.2 0000 0000 9320 7537 Metabolomics Australia The University of Queensland 4072 Brisbane QLD Australia
| | - Nicholas Cowie
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
| | - Glenn Moonen
- Zoetis. 45 Poplar Road 3052 Parkville VIC Australia
| | | | - John Power
- Zoetis. 45 Poplar Road 3052 Parkville VIC Australia
| | - Lars K Nielsen
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.1003.2 0000 0000 9320 7537 Metabolomics Australia The University of Queensland 4072 Brisbane QLD Australia
- grid.5170.3 0000 0001 2181 8870 The Novo Nordisk Foundation Centre for Biosustainability Technical University of Denmark Kgs. Lyngby Denmark
| | - Esteban Marcellin
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.1003.2 0000 0000 9320 7537 Metabolomics Australia The University of Queensland 4072 Brisbane QLD Australia
| |
Collapse
|
41
|
Humans Surviving Cholera Develop Antibodies against Vibrio cholerae O-Specific Polysaccharide That Inhibit Pathogen Motility. mBio 2020; 11:mBio.02847-20. [PMID: 33203761 PMCID: PMC7683404 DOI: 10.1128/mbio.02847-20] [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] [Indexed: 12/26/2022] Open
Abstract
Cholera is a severe dehydrating illness of humans caused by Vibrio cholerae. V. cholerae is a highly motile bacterium that has a single flagellum covered in lipopolysaccharide (LPS) displaying O-specific polysaccharide (OSP), and V. cholerae motility correlates with its ability to cause disease. The mechanisms of protection against cholera are not well understood; however, since V. cholerae is a noninvasive intestinal pathogen, it is likely that antibodies that bind the pathogen or its products in the intestinal lumen contribute to protection from infection. Here, we demonstrate that OSP-specific antibodies isolated from humans surviving cholera in Bangladesh inhibit V. cholerae motility and are associated with protection against challenge in a motility-dependent manner. The mechanism of protection against cholera afforded by previous illness or vaccination is currently unknown. We have recently shown that antibodies targeting O-specific polysaccharide (OSP) of Vibrio cholerae correlate highly with protection against cholera. V. cholerae is highly motile and possesses a flagellum sheathed in OSP, and motility of V. cholerae correlates with virulence. Using high-speed video microscopy and building upon previous animal-related work, we demonstrate that sera, polyclonal antibody fractions, and OSP-specific monoclonal antibodies recovered from humans surviving cholera block V. cholerae motility at both subagglutinating and agglutinating concentrations. This antimotility effect is reversed by preadsorbing sera and polyclonal antibody fractions with purified OSP and is associated with OSP-specific but not flagellin-specific monoclonal antibodies. Fab fragments of OSP-specific polyclonal antibodies do not inhibit motility, suggesting a requirement for antibody-mediated cross-linking in motility inhibition. We show that OSP-specific antibodies do not directly affect V. cholerae viability, but that OSP-specific monoclonal antibody highly protects against death in the murine cholera model. We used in vivo competitive index studies to demonstrate that OSP-specific antibodies impede colonization and survival of V. cholerae in intestinal tissues and that this impact is motility dependent. Our findings suggest that the impedance of motility by antibodies targeting V. cholerae OSP contributes to protection against cholera.
Collapse
|
42
|
Fu H, Yu P, Liang W, Kan B, Peng X, Chen L. Virulence, Resistance, and Genomic Fingerprint Traits of Vibrio cholerae Isolated from 12 Species of Aquatic Products in Shanghai, China. Microb Drug Resist 2020; 26:1526-1539. [PMID: 33156741 PMCID: PMC7757592 DOI: 10.1089/mdr.2020.0269] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Vibrio cholerae is a waterborne bacterium and can cause epidemic cholera disease worldwide. Continuous monitoring of V. cholerae contamination in aquatic products is imperative for assuring food safety. In this study, we determined virulence, antimicrobial susceptibility, heavy metal tolerance, and genomic fingerprints of 370 V. cholerae isolates recovered from 12 species of commonly consumed aquatic products collected from July to September of 2018 in Shanghai, China. Among the species, Leiocassis longirostris, Ictalurus punetaus, Ophiocephalus argus Cantor, and Pelteobagrus fulvidraco were for the first time detected for V. cholerae. Toxin genes ctxAB, tcpA, ace, and zot were absent from all the V. cholerae isolates. However, high occurrence of virulence-associated genes was detected, such as hapA (82.7%), hlyA (81.4%), rtxCABD (81.4%, 24.3%, 80.3%, and 80.8%, respectively), and tlh (80.5%). Approximately 62.2% of the 370 V. cholerae isolates exhibited resistance to streptomycin, followed by ampicillin (60.3%), rifampicin (53.8%), trimethoprim (38.4%), and sulfamethoxazole-trimethoprim (37.0%). Moreover, ∼57.6% of the isolates showed multidrug resistant phenotypes with 57 resistance profiles, which was significantly different among the 12 species (multiple antimicrobial resistance index, p < 0.001). Meanwhile, high incidence of tolerance to heavy metals Hg2+ (69.5%), Ni2+ (32.4%), and Cd2+ (30.8%) was observed among the isolates. The enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR)-based fingerprinting profiles classified the 370 V. cholerae isolates into 239 different ERIC-genotypes, which demonstrated diverse genomic variation among the isolates. Overall, the results in this study meet the increasing need of food safety risk assessment of aquatic products.
Collapse
Affiliation(s)
- Huiyu Fu
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), China Ministry of Agriculture, College of Food Science and Technology, Shanghai Ocean University, Shanghai, People's Republic of China
| | - Pan Yu
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), China Ministry of Agriculture, College of Food Science and Technology, Shanghai Ocean University, Shanghai, People's Republic of China
| | - Weili Liang
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Biao Kan
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Xu Peng
- Archaea Centre, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lanming Chen
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), China Ministry of Agriculture, College of Food Science and Technology, Shanghai Ocean University, Shanghai, People's Republic of China
| |
Collapse
|
43
|
Gao H, Ma L, Qin Q, Qiu Y, Zhang J, Li J, Lou J, Diao B, Zhao H, Shi Q, Zhang Y, Kan B. Fur Represses Vibrio cholerae Biofilm Formation via Direct Regulation of vieSAB, cdgD, vpsU, and vpsA-K Transcription. Front Microbiol 2020; 11:587159. [PMID: 33193241 PMCID: PMC7641913 DOI: 10.3389/fmicb.2020.587159] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 09/25/2020] [Indexed: 12/21/2022] Open
Abstract
Attached Vibrio cholerae biofilms are essential for environmental persistence and infectivity. The vps loci (vpsU, vpsA-K, and vpsL-Q) are required for mature biofilm formation and are responsible for the synthesis of exopolysaccharide. Transcription of vps genes is activated by the signaling molecule bis-(3'-5')-cyclic di-GMP (c-di-GMP), whose metabolism is controlled by the proteins containing the GGDEF and/or EAL domains. The ferric uptake regulator (Fur) plays key roles in the transcription of many genes involved in iron metabolism and non-iron functions. However, roles for Fur in Vibrio biofilm production have not been documented. In this study, phenotypic assays demonstrated that Fur, independent of iron, decreases in vivo c-di-GMP levels and inhibits in vitro biofilm formation by Vibrio cholerae. The Fur box-like sequences were detected within the promoter-proximal DNA regions of vpsU, vpsA-K, vieSAB, and cdgD, suggesting that transcription of these genes may be under the direct control of Fur. Indeed, the results of luminescence, quantitative PCR (qPCR), electrophoretic mobility shift assay (EMSA), and DNase I footprinting assays demonstrated Fur to bind to the promoter-proximal DNA regions of vpsU, vpsA-K, and cdgD to repress their transcription. In contrast, Fur activates the transcription of vieSAB in a direct manner. The cdgD and vieSAB encode proteins with GGDEF and EAL domains, respectively. Thus, data presented here highlight a new physiological role for Fur wherein it acts as a repressor of V. cholerae biofilm formation mediated by decreasing the production of exopolysaccharide and the intracellular levels of c-di-GMP.
Collapse
Affiliation(s)
- He Gao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Lizhi Ma
- Third Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Qin Qin
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yue Qiu
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Jingyun Zhang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jie Li
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jing Lou
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Baowei Diao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Hongqun Zhao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Qiannan Shi
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yiquan Zhang
- School of Medicine, Jiangsu University, Zhenjiang, China.,Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Biao Kan
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| |
Collapse
|
44
|
Ramamurthy T, Nandy RK, Mukhopadhyay AK, Dutta S, Mutreja A, Okamoto K, Miyoshi SI, Nair GB, Ghosh A. Virulence Regulation and Innate Host Response in the Pathogenicity of Vibrio cholerae. Front Cell Infect Microbiol 2020; 10:572096. [PMID: 33102256 PMCID: PMC7554612 DOI: 10.3389/fcimb.2020.572096] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023] Open
Abstract
The human pathogen Vibrio cholerae is the causative agent of severe diarrheal disease known as cholera. Of the more than 200 "O" serogroups of this pathogen, O1 and O139 cause cholera outbreaks and epidemics. The rest of the serogroups, collectively known as non-O1/non-O139 cause sporadic moderate or mild diarrhea and also systemic infections. Pathogenic V. cholerae circulates between nutrient-rich human gut and nutrient-deprived aquatic environment. As an autochthonous bacterium in the environment and as a human pathogen, V. cholerae maintains its survival and proliferation in these two niches. Growth in the gastrointestinal tract involves expression of several genes that provide bacterial resistance against host factors. An intricate regulatory program involving extracellular signaling inputs is also controlling this function. On the other hand, the ability to store carbon as glycogen facilitates bacterial fitness in the aquatic environment. To initiate the infection, V. cholerae must colonize the small intestine after successfully passing through the acid barrier in the stomach and survive in the presence of bile and antimicrobial peptides in the intestinal lumen and mucus, respectively. In V. cholerae, virulence is a multilocus phenomenon with a large functionally associated network. More than 200 proteins have been identified that are functionally linked to the virulence-associated genes of the pathogen. Several of these genes have a role to play in virulence and/or in functions that have importance in the human host or the environment. A total of 524 genes are differentially expressed in classical and El Tor strains, the two biotypes of V. cholerae serogroup O1. Within the host, many immune and biological factors are able to induce genes that are responsible for survival, colonization, and virulence. The innate host immune response to V. cholerae infection includes activation of several immune protein complexes, receptor-mediated signaling pathways, and other bactericidal proteins. This article presents an overview of regulation of important virulence factors in V. cholerae and host response in the context of pathogenesis.
Collapse
Affiliation(s)
| | - Ranjan K Nandy
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Asish K Mukhopadhyay
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Shanta Dutta
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Ankur Mutreja
- Global Health-Infectious Diseases, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Keinosuke Okamoto
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.,Collaborative Research Center of Okayama University for Infectious Diseases in India, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Shin-Ichi Miyoshi
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - G Balakrish Nair
- Microbiome Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
| | - Amit Ghosh
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| |
Collapse
|
45
|
Vance TDR, Ye Q, Conroy B, Davies PL. Essential role of calcium in extending RTX adhesins to their target. JOURNAL OF STRUCTURAL BIOLOGY-X 2020; 4:100036. [PMID: 32984811 PMCID: PMC7493085 DOI: 10.1016/j.yjsbx.2020.100036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/12/2020] [Accepted: 09/02/2020] [Indexed: 11/25/2022]
Abstract
Elongated beta-sandwich repeats are a major part of bacterial RTX adhesins. The repeats are arranged in tandem to extend away from the bacterial surface. Calcium ions are coordinated in the linkers between repeats to stiffen the protein. Rigidification of the tandem repeats further helps extension of the adhesin. The repeats differ greatly between species, but all have Ca2+ in their linkers.
RTX adhesins are long, multi-domain proteins present on the outer membrane of many Gram-negative bacteria. From this vantage point, adhesins use their distal ligand-binding domains for surface attachment leading to biofilm formation. To expand the reach of the ligand-binding domains, RTX adhesins maintain a central extender region of multiple tandem repeats, which makes up most of the proteins’ large molecular weight. Alignments of the 10-15-kDa extender domains show low sequence identity between adhesins. Here we have produced and structurally characterized protein constructs of four tandem repeats (tetra-tandemers) from two different RTX adhesins. In comparing the tetra-tandemers to each other and already solved structures from Marinomonas primoryensis and Salmonella enterica, the extender domains fold as diverse beta-sandwich structures with widely differing calcium contents. However, all the tetra-tandemers have at least one calcium ion coordinated in the linker region between beta-sandwich domains whose role appears to be the rigidification of the extender region to help the adhesin extend its reach.
Collapse
Affiliation(s)
- Tyler D R Vance
- Department of Biomedical and Molecular Science, Queen's University Kingston ON, Canada
| | - Qilu Ye
- Department of Biomedical and Molecular Science, Queen's University Kingston ON, Canada
| | - Brigid Conroy
- Department of Biomedical and Molecular Science, Queen's University Kingston ON, Canada
| | - Peter L Davies
- Department of Biomedical and Molecular Science, Queen's University Kingston ON, Canada
| |
Collapse
|
46
|
Khan F, Tabassum N, Anand R, Kim YM. Motility of Vibrio spp.: regulation and controlling strategies. Appl Microbiol Biotechnol 2020; 104:8187-8208. [PMID: 32816086 DOI: 10.1007/s00253-020-10794-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 07/15/2020] [Accepted: 07/19/2020] [Indexed: 12/12/2022]
Abstract
Flagellar motility in bacteria is a highly regulated and complex cellular process that requires high energy investment for movement and host colonization. Motility plays an important role in the lifestyle of Vibrio spp. in the aquatic environment and during host colonization. Flagellar motility in vibrios is associated with several cellular processes, such as movement, colonization, adhesion, biofilm formation, and virulence. The transcription of all flagella-related genes occurs hierarchically and is regulated positively or negatively by several transcription factors and regulatory proteins. The flagellar regulatory hierarchy is well studied in Vibrio cholerae and Vibrio parahaemolyticus. Here, we compared the regulatory cascade and molecules involved in the flagellar motility of V. cholerae and V. parahaemolyticus in detail. The evolutionary relatedness of the master regulator of the polar and lateral flagella in different Vibrio species is also discussed. Although they can form symbiotic associations of some Vibrio species with humans and aquatic organisms can be harmed by several species of Vibrio as a result of surface contact, characterized by flagellar movement. Thus, targeting flagellar motility in pathogenic Vibrio species is considered a promising approach to control Vibrio infections. This approach, along with the strategies for controlling flagellar motility in different species of Vibrio using naturally derived and chemically synthesized compounds, is discussed in this review. KEY POINTS: • Vibrio species are ubiquitous and distributed across the aquatic environments. • The flagellar motility is responsible for the chemotactic movement and initial colonization to the host. • The transition from the motile into the biofilm stage is one of the crucial events in the infection. • Several signaling pathways are involved in the motility and formation of biofilm. • Attenuation of motility by naturally derived or chemically synthesized compounds could be a potential treatment for preventing Vibrio biofilm-associated infections.
Collapse
Affiliation(s)
- Fazlurrahman Khan
- Institute of Food Science, Pukyong National University, Busan, 48513, South Korea.
| | - Nazia Tabassum
- Industrial Convergence Bionix Engineering, Pukyong National University, Busan, 48513, Republic of Korea
| | - Raksha Anand
- Department of Life Science, School of Basic Science and Research, Sharda University, 201306, Greater Noida, U.P., India
| | - Young-Mog Kim
- Institute of Food Science, Pukyong National University, Busan, 48513, South Korea. .,Department of Food Science and Technology, Pukyong National University, Busan, 48513, South Korea.
| |
Collapse
|
47
|
Hirsch N, Kappe E, Gangl A, Schwartz K, Mayer-Scholl A, Hammerl JA, Strauch E. Phenotypic and Genotypic Properties of Vibrio cholerae non-O1, non-O139 Isolates Recovered from Domestic Ducks in Germany. Microorganisms 2020; 8:microorganisms8081104. [PMID: 32717968 PMCID: PMC7463538 DOI: 10.3390/microorganisms8081104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/17/2020] [Accepted: 07/21/2020] [Indexed: 01/08/2023] Open
Abstract
Vibrio cholerae non-O1, non-O139 bacteria are natural inhabitants of aquatic ecosystems and have been sporadically associated with human infections. They mostly lack the two major virulence factors of toxigenic V. cholerae serogroups O1 and O139 strains, which are the causative agent of cholera. Non-O1, non-O139 strains are found in water bodies, sediments, and in association with other aquatic organisms. Occurrence of these bacteria in fecal specimens of waterfowl were reported, and migratory birds likely contribute to the long-distance transfer of strains. We investigated four V. cholerae non-O1, non-O139 isolates for phenotypic traits and by whole genome sequencing (WGS). The isolates were recovered from organs of domestic ducks with serious disease symptoms. WGS data revealed only a distant genetic relationship between all isolates. The isolates harbored a number of virulence factors found in most V. cholerae strains. Specific virulence factors of non-O1, non-O139 strains, such as the type III secretion system (TTSS) or cholix toxin, were observed. An interesting observation is that all isolates possess multifunctional autoprocessing repeats-in-toxin toxins (MARTX) closely related to the MARTX of toxigenic El Tor O1 strains. Different primary sequences of the abundant OmpU proteins could indicate a significant role of this virulence factor. Phenotypic characteristics such as hemolysis and antimicrobial resistance (AMR) were studied. Three isolates showed susceptibility to a number of tested antimicrobials, and one strain possessed AMR genes located in an integron. Knowledge of the environmental occurrence of V. cholerae non-O1, non-O139 in Germany is limited. The source of the infection of the ducks is currently unknown. In the context of the ‘One Health’ concept, it is desirable to study the ecology of V. cholerae non-O1, non-O139, as it cannot be excluded that the isolates possess zoonotic potential and could cause infections in humans.
Collapse
Affiliation(s)
- Nicola Hirsch
- Tiergesundheitsdienst Bayern, Bavarian Animal Health Service, 85586 Poing, Germany; (N.H.); (E.K.); (A.G.)
| | - Eva Kappe
- Tiergesundheitsdienst Bayern, Bavarian Animal Health Service, 85586 Poing, Germany; (N.H.); (E.K.); (A.G.)
| | - Armin Gangl
- Tiergesundheitsdienst Bayern, Bavarian Animal Health Service, 85586 Poing, Germany; (N.H.); (E.K.); (A.G.)
| | - Keike Schwartz
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D-10589 Berlin, Germany; (K.S.); (A.M.-S.); (J.A.H.)
| | - Anne Mayer-Scholl
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D-10589 Berlin, Germany; (K.S.); (A.M.-S.); (J.A.H.)
| | - Jens Andre Hammerl
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D-10589 Berlin, Germany; (K.S.); (A.M.-S.); (J.A.H.)
| | - Eckhard Strauch
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D-10589 Berlin, Germany; (K.S.); (A.M.-S.); (J.A.H.)
- Correspondence:
| |
Collapse
|
48
|
Jäckel C, Hammerl JA, Arslan HHT, Göllner C, vom Ort N, Taureck K, Strauch E. Phenotypic and Genotypic Characterization of Veterinary Vibrio cincinnatiensis Isolates. Microorganisms 2020; 8:E739. [PMID: 32429107 PMCID: PMC7285037 DOI: 10.3390/microorganisms8050739] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/07/2020] [Accepted: 05/13/2020] [Indexed: 11/16/2022] Open
Abstract
Vibrio cincinnatiensis is a halophilic species which has been found in marine and estuarine environments worldwide. The species is considered a rare pathogen for which the significance for humans is unclear. In this study, nine veterinary isolates were investigated that were obtained from domestic animals in Germany. The isolates were mostly recovered from abortion material of pigs, cattle, and horse (amnion or fetuses). One isolate was from a goose. A human clinical strain from a case of enteritis in Germany described in the literature was also included in the study. Whole-genome sequencing (WGS) of all isolates and MALDI-TOF MS (matrix-assisted-laser-desorption/ionization time-of-flight mass spectrometry) were performed to verify the species assignment. All strains were investigated for phenotypic traits including antimicrobial resistance (AMR), biochemical properties, and two virulence-associated phenotypes (hemolytic activity and resistance to human serum). WGS data and MS spectra confirmed that all veterinary isolates are closely related to the type strain V. cincinnatiensis NCTC12012. An exception was the human isolate from Germany which is related to the other isolates but could belong to another species. The isolates were similar in most biochemical phenotypes. Only one strain showed a very weak hemolytic activity against sheep erythrocytes, and serum resistance was intermediate in two strains. AMR phenotypes were more variable between the isolates. Resistances were observed against ß-lactams ampicillin and cefoxitin and against tetracycline and the sulfonamide antibiotics trimethoprim and sulfamethoxazole. Some acquired AMR genes were identified by bioinformatics analyses. WGS and MALDI-TOF MS data reveal a close relationship of the veterinary isolates and the type strain V. cincinnatiensis NCTC12012, which is a clinical human isolate. As the veterinary isolates of this study were mostly recovered from abortion material (amnions and fetuses), a zoonotic potential of the veterinary isolates seems possible.
Collapse
Affiliation(s)
- Claudia Jäckel
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D–10589 Berlin, Germany; (C.J.); (J.A.H.); (H.-H.-T.A.); (C.G.); (N.v.O.)
| | - Jens Andre Hammerl
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D–10589 Berlin, Germany; (C.J.); (J.A.H.); (H.-H.-T.A.); (C.G.); (N.v.O.)
| | - Huynh-Huong-Thao Arslan
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D–10589 Berlin, Germany; (C.J.); (J.A.H.); (H.-H.-T.A.); (C.G.); (N.v.O.)
| | - Cornelia Göllner
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D–10589 Berlin, Germany; (C.J.); (J.A.H.); (H.-H.-T.A.); (C.G.); (N.v.O.)
| | - Nicole vom Ort
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D–10589 Berlin, Germany; (C.J.); (J.A.H.); (H.-H.-T.A.); (C.G.); (N.v.O.)
| | - Karin Taureck
- Landesuntersuchungsanstalt für das Gesundheits- und Veterinärwesen Sachsen, 01099 Standort Dresden, Germany;
| | - Eckhard Strauch
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D–10589 Berlin, Germany; (C.J.); (J.A.H.); (H.-H.-T.A.); (C.G.); (N.v.O.)
| |
Collapse
|
49
|
Reciprocal c-di-GMP signaling: Incomplete flagellum biogenesis triggers c-di-GMP signaling pathways that promote biofilm formation. PLoS Genet 2020; 16:e1008703. [PMID: 32176702 PMCID: PMC7098655 DOI: 10.1371/journal.pgen.1008703] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 03/26/2020] [Accepted: 03/01/2020] [Indexed: 11/25/2022] Open
Abstract
The assembly status of the V. cholerae flagellum regulates biofilm formation, suggesting that the bacterium senses a lack of movement to commit to a sessile lifestyle. Motility and biofilm formation are inversely regulated by the second messenger molecule cyclic dimeric guanosine monophosphate (c-di-GMP). Therefore, we sought to define the flagellum-associated c-di-GMP-mediated signaling pathways that regulate the transition from a motile to a sessile state. Here we report that elimination of the flagellum, via loss of the FlaA flagellin, results in a flagellum-dependent biofilm regulatory (FDBR) response, which elevates cellular c-di-GMP levels, increases biofilm gene expression, and enhances biofilm formation. The strength of the FDBR response is linked with status of the flagellar stator: it can be reversed by deletion of the T ring component MotX, and reduced by mutations altering either the Na+ binding ability of the stator or the Na+ motive force. Absence of the stator also results in reduction of mannose-sensitive hemagglutinin (MSHA) pilus levels on the cell surface, suggesting interconnectivity of signal transduction pathways involved in biofilm formation. Strains lacking flagellar rotor components similarly launched an FDBR response, however this was independent of the status of assembly of the flagellar stator. We found that the FDBR response requires at least three specific diguanylate cyclases that contribute to increased c-di-GMP levels, and propose that activation of biofilm formation during this response relies on c-di-GMP-dependent activation of positive regulators of biofilm production. Together our results dissect how flagellum assembly activates c-di-GMP signaling circuits, and how V. cholerae utilizes these signals to transition from a motile to a sessile state. A key regulator of Vibrio cholerae physiology is the nucleotide-based, second messenger cyclic dimeric guanosine monophosphate (c-di-GMP). We found that the status of flagellar biosynthesis at different stages of flagellar assembly modulates c-di-GMP signaling in V. cholerae and identified diguanylate cyclases involved in this regulatory process. The effect of motility status on the cellular c-di-GMP level is partly dependent on the flagellar stator and Na+ flux through the flagellum. Finally, we showed that c-di-GMP-dependent positive regulators of biofilm formation are critical for the signaling cascade that connects motility status to biofilm formation. Our results show that in addition to c-di-GMP promoting motile to biofilm lifestyle switch, “motility status” of V. cholerae modulates c-di-GMP signaling and biofilm formation.
Collapse
|
50
|
The Bacterial Enhancer Binding Protein VasH Promotes Expression of a Type VI Secretion System in Vibrio fischeri during Symbiosis. J Bacteriol 2020; 202:JB.00777-19. [PMID: 31964698 DOI: 10.1128/jb.00777-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 01/13/2020] [Indexed: 11/20/2022] Open
Abstract
Vibrio fischeri is a bacterial symbiont that colonizes the light organ of the Hawaiian bobtail squid, Euprymna scolopes Certain strains of V. fischeri express a type VI secretion system (T6SS), which delivers effectors into neighboring cells that result in their death. Strains that are susceptible to the T6SS fail to establish symbiosis with a T6SS-positive strain within the same location of the squid light organ, which is a phenomenon termed strain incompatibility. This study investigates the regulation of the T6SS in V. fischeri strain FQ-A001. Here, we report that the expression of Hcp, a necessary structural component of the T6SS, depends on the alternative sigma factor σ54 and the bacterial enhancer binding protein VasH. VasH is necessary for FQ-A001 to kill other strains, suggesting that VasH-dependent regulation is essential for the T6SS of V. fischeri to affect intercellular interactions. In addition, this study demonstrates VasH-dependent transcription of hcp within host-associated populations of FQ-A001, suggesting that the T6SS is expressed within the host environment. Together, these findings establish a model for transcriptional control of hcp in V. fischeri within the squid light organ, thereby increasing understanding of how the T6SS is regulated during symbiosis.IMPORTANCE Animals harbor bacterial symbionts with specific traits that promote host fitness. Mechanisms that facilitate intercellular interactions among bacterial symbionts impact which bacterial lineages ultimately establish symbiosis with the host. How these mechanisms are regulated is poorly characterized in nonhuman bacterial symbionts. This study establishes a model for the transcriptional regulation of a contact-dependent killing machine, thereby increasing understanding of mechanisms by which different strains compete while establishing symbiosis.
Collapse
|