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Pogoreutz C, Ziegler M. Frenemies on the reef? Resolving the coral-Endozoicomonas association. Trends Microbiol 2024; 32:422-434. [PMID: 38216372 DOI: 10.1016/j.tim.2023.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/09/2023] [Accepted: 11/13/2023] [Indexed: 01/14/2024]
Abstract
Stony corals are poster child holobionts due to their intimate association with diverse microorganisms from all domains of life. We are only beginning to understand the diverse functions of most of these microbial associates, including potential main contributors to holobiont health and resilience. Among these, bacteria of the elusive genus Endozoicomonas are widely perceived as beneficial symbionts based on their genomic potential and their high prevalence and ubiquitous presence in coral tissues. Simultaneously, evidence of pathogenic and parasitic Endozoicomonas lineages in other marine animals is emerging. Synthesizing the current knowledge on the association of Endozoicomonas with marine holobionts, we challenge the perception of a purely mutualistic coral-Endozoicomonas relationship and propose directions to elucidate its role along the symbiotic spectrum.
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Affiliation(s)
- Claudia Pogoreutz
- EPHE-UPVD-CNRS, UAR 3278 CRIOBE, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan Cedex, France.
| | - Maren Ziegler
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32 (IFZ), 35392, Giessen, Germany.
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2
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Poojara L, K R, Rawal RM. Computational approaches screening DNA aptamers against conserved outer membrane protein W of Vibrio cholerae O1- an investigation expanding the potential for point-of-care detection with aptasensors. J Biomol Struct Dyn 2023; 41:14438-14449. [PMID: 36812260 DOI: 10.1080/07391102.2023.2181634] [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: 01/05/2023] [Accepted: 02/12/2023] [Indexed: 02/24/2023]
Abstract
Foodborne outbreaks urge public health domain to upgrade diagnosis by means of simpler, quicker, and more affordable pathogen detection methods. A molecular recognition probe against an analyte of interest makes up a biosensor, along with a method for turning the recognition event into a quantifiable signal. Single-stranded DNA or RNA aptamers are promising bio-recognition molecules for a range of targets, including a wide range of non-nucleic acid targets with which they are highly specific and affine. In the proposed study, 40 DNA aptamers were screened and analyzed interactions using in-silico SELEX procedures, which can selectively interact with active sites at the extracellular region of the Outer membrane Protein W (OmpW) of Vibrio Cholerae. Multiple modeling techniques, like protein structural prediction with I-TASSER, aptamer structural modeling using M-fold, RNA composer, protein-DNA docking using HADDOCK, and large-scale (500 ns) molecular dynamics simulations through GROMACS have been employed. Out of 40, six aptamers having lowest free energy were docked against the predicted active site at the extracellular region of OmpW. VBAPT4-OmpW and VBAPT17-OmpW, the two highest-scoring Aptamer-Protein complexes, were chosen for molecular dynamics simulations. VBAPT4-OmpW is quite unable to attain its structural local minima after 500 ns. But VBAPT17-OmpW is showing great stability and is not destructive even after 500 ns. RMSF, DSSP, PCA, and Essential Dynamics all provided additional confirmation. Current findings, combined with the fabrication of biosensor devices, could pave the way for an innovative pathogen detection platform with high sensitivity, along with an effective and low-impact curative strategy for corresponding diseases.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Lipi Poojara
- Department of Biochemistry & Forensic Science, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
| | - Ram K
- Department of Biotechnology, Kumaraguru College of Technology, Coimbatore, Tamil Nadu, India
| | - Rakesh M Rawal
- Department of Biochemistry & Forensic Science, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
- Department of Life Science, School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
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3
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Structure, regulation, and host interaction of outer membrane protein U (OmpU) of Vibrio species. Microb Pathog 2021; 162:105267. [PMID: 34718127 DOI: 10.1016/j.micpath.2021.105267] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/30/2021] [Accepted: 10/20/2021] [Indexed: 01/22/2023]
Abstract
OmpU is a multimeric, cation selective outer membrane protein of Vibrio and related species that non-covalently interact with peptidoglycan layer. Interaction of OmpU with human host cells triggers signaling pathways to promote cytokine secretion, reactive oxygen species production, and caspase independent death in immune and epithelial cells. Non-choleric OmpU imparts resistance to antimicrobial peptides and induces actin cytoskeletal reorganization in the host cells. Further, OmpU isolated from Vibrio species elicits an immune response in several aquaculture hosts. Importantly, in-vivo studies using recombinant OmpU or OmpU derived mimotopes reveal a short-lasting immunity, and protection against Vibrio in the aquaculture sector. In conclusion, OmpU is a key adhesion protein and an important virulence factor for successful colonization of Vibrio species into hosts. This review article provides a broad overview of structural, regulatory, and functional mechanisms of OmpU in normal and disease states.
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Lv T, Dai F, Zhuang Q, Zhao X, Shao Y, Guo M, Lv Z, Li C, Zhang W. Outer membrane protein OmpU is related to iron balance in Vibrio alginolyticus. Microbiol Res 2019; 230:126350. [PMID: 31629270 DOI: 10.1016/j.micres.2019.126350] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/01/2019] [Accepted: 10/06/2019] [Indexed: 12/14/2022]
Abstract
Outer membrane protein U (OmpU) is a major porin from Vibrio alginolyticus and has been considered a vaccine candidate against infection by V. alginolyticus. After pre-incubated with polyclonal antibody against rOmpU, V. alginolyticus showed a 78% decrease in extracellular iron level, suggesting that interruption of OmpU could increase intracellular iron level. The mRNA expression of ompU under iron-limited conditions was determined using real-time reverse transcriptase PCR. The mRNA level of ompU was downregulated to 0.27-, 0.036- and 0.019-fold after the addition of the iron chelator 2,2'-bipyridyl for 10, 30 and 60 min, respectively. In addition, the promoter of ompU contained a ferric uptake regulator (Fur) binding site, which revealed the potential regulation of ompU by Fur and iron. Fur from V. alginolyticus was purified and used for electrophoretic mobility shift assay. The result showed that in the absence of Fe2+, purified recombinant Fur could specifically bind to the promoter DNA of ompU, while in the presence of Fe2+, the binding of Fur and the promoter DNA was suppressed. Our study preliminarily explored the function of OmpU in iron balance in V. alginolyticus, and these findings were helpful in understanding iron metabolism in V. alginolyticus.
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Affiliation(s)
- Tengteng Lv
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Fa Dai
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Qiuting Zhuang
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Xuelin Zhao
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Yina Shao
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Ming Guo
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Zhimeng Lv
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Chenghua Li
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, PR China
| | - Weiwei Zhang
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China.
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Lynch JB, Schwartzman JA, Bennett BD, McAnulty SJ, Knop M, Nyholm SV, Ruby EG. Ambient pH Alters the Protein Content of Outer Membrane Vesicles, Driving Host Development in a Beneficial Symbiosis. J Bacteriol 2019; 201:e00319-19. [PMID: 31331976 PMCID: PMC6755730 DOI: 10.1128/jb.00319-19] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/03/2019] [Indexed: 12/31/2022] Open
Abstract
Outer membrane vesicles (OMVs) are continuously produced by Gram-negative bacteria and are increasingly recognized as ubiquitous mediators of bacterial physiology. In particular, OMVs are powerful effectors in interorganismal interactions, driven largely by their molecular contents. These impacts have been studied extensively in bacterial pathogenesis but have not been well documented within the context of mutualism. Here, we examined the proteomic composition of OMVs from the marine bacterium Vibrio fischeri, which forms a specific mutualism with the Hawaiian bobtail squid, Euprymna scolopes We found that V. fischeri upregulates transcription of its major outer membrane protein, OmpU, during growth at an acidic pH, which V. fischeri experiences when it transitions from its environmental reservoir to host tissues. We used comparative genomics and DNA pulldown analyses to search for regulators of ompU and found that differential expression of ompU is governed by the OmpR, H-NS, and ToxR proteins. This transcriptional control combines with nutritional conditions to govern OmpU levels in OMVs. Under a host-encountered acidic pH, V. fischeri OMVs become more potent stimulators of symbiotic host development in an OmpU-dependent manner. Finally, we found that symbiotic development could be stimulated by OMVs containing a homolog of OmpU from the pathogenic species Vibrio cholerae, connecting the role of a well-described virulence factor with a mutualistic element. This work explores the symbiotic effects of OMV variation, identifies regulatory machinery shared between pathogenic and mutualistic bacteria, and provides evidence of the role that OMVs play in animal-bacterium mutualism.IMPORTANCE Beneficial bacteria communicate with their hosts through a variety of means. These communications are often carried out by a combination of molecules that stimulate responses from the host and are necessary for development of the relationship between these organisms. Naturally produced bacterial outer membrane vesicles (OMVs) contain many of those molecules and can stimulate a wide range of responses from recipient organisms. Here, we describe how a marine bacterium, Vibrio fischeri, changes the makeup of its OMVs under conditions that it experiences as it goes from its free-living lifestyle to associating with its natural host, the Hawaiian bobtail squid. This work improves our understanding of how bacteria change their signaling profile as they begin to associate with their beneficial partner animals.
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Affiliation(s)
- Jonathan B Lynch
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Julia A Schwartzman
- Department of Medical Microbiology & Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Brittany D Bennett
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Sarah J McAnulty
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Mirjam Knop
- Department of Molecular Physiology, Zoology, Kiel University, Kiel, Germany
| | - Spencer V Nyholm
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Edward G Ruby
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, Hawaii, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin, Madison, Wisconsin, USA
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Schwartzman JA, Lynch JB, Ramos SF, Zhou L, Apicella MA, Yew JY, Ruby EG. Acidic pH promotes lipopolysaccharide modification and alters colonization in a bacteria-animal mutualism. Mol Microbiol 2019; 112:1326-1338. [PMID: 31400167 PMCID: PMC6823639 DOI: 10.1111/mmi.14365] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2019] [Indexed: 02/06/2023]
Abstract
Environmental pH can be an important cue for symbiotic bacteria as they colonize their eukaryotic hosts. Using the model mutualism between the marine bacterium Vibrio fischeri and the Hawaiian bobtail squid, we characterized the bacterial transcriptional response to acidic pH experienced during the shift from planktonic to host-associated lifestyles. We found several genes involved in outer membrane structure were differentially expressed based on pH, indicating alterations in membrane physiology as V. fischeri initiates its symbiotic program. Exposure to host-like pH increased the resistance of V. fischeri to the cationic antimicrobial peptide polymixin B, which resembles antibacterial molecules that are produced by the squid to select V. fischeri from the ocean microbiota. Using a forward genetic screen, we identified a homolog of eptA, a predicted phosphoethanolamine transferase, as critical for antimicrobial defense. We used MALDI-MS to verify eptA as an ethanolamine transferase for the lipid-A portion of V. fischeri lipopolysaccharide. We then used a DNA pulldown approach to discover that eptA transcription is activated by the global regulator H-NS. Finally, we revealed that eptA promotes successful squid colonization by V. fischeri, supporting its potential role in initiation of this highly specific symbiosis.
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Affiliation(s)
- Julia A. Schwartzman
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison WI, USA
| | - Jonathan B. Lynch
- Pacific Biosciences Research Center, University of Hawaii-Manoa, Honolulu HI, USA
| | | | - Lawrence Zhou
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison WI, USA
| | - Michael A. Apicella
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City IA, USA
| | - Joanne Y. Yew
- Pacific Biosciences Research Center, University of Hawaii-Manoa, Honolulu HI, USA
| | - Edward G. Ruby
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison WI, USA
- Pacific Biosciences Research Center, University of Hawaii-Manoa, Honolulu HI, USA
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7
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Rashid MI, Rehman S, Ali A, Andleeb S. Fishing for vaccines against Vibrio cholerae using in silico pan-proteomic reverse vaccinology approach. PeerJ 2019; 7:e6223. [PMID: 31249730 PMCID: PMC6589079 DOI: 10.7717/peerj.6223] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 12/05/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Cholera, an acute enteric infection, is a serious health challenge in both the underdeveloped and the developing world. It is caused by Vibrio cholerae after ingestion of fecal contaminated food or water. Cholera outbreaks have recently been observed in regions facing natural calamities (i.e., earthquake in Haiti 2010) or war (i.e., ongoing civil war in Yemen 2016) where healthcare and sanitary setups have been disrupted as a consequence. Whole-cell oral cholera vaccines (OCVs) have been in market but their regimen efficacy has been questioned. A reverse vaccinology (RV) approach has been applied as a successful anti-microbial measure for many infectious diseases. METHODOLOGY With the aim of finding new protective antigens for vaccine development, the V. cholerae O1 (biovar eltr str. N16961) proteome was computationally screened in a sequential prioritization approach that focused on determining the antigenicity of potential vaccine candidates. Essential, accessible, virulent and immunogenic proteins were selected as potential candidates. The predicted epitopes were filtered for effective binding with MHC alleles and epitopes binding with greater MHC alleles were selected. RESULTS In this study, we report lipoprotein NlpD, outer membrane protein OmpU, accessory colonization factor AcfA, Porin, putative and outer membrane protein OmpW as potential candidates qualifying all the set criteria. These predicted epitopes can offer a potential for development of a reliable peptide or subunit vaccine for V. cholerae.
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Affiliation(s)
- Muhammad I. Rashid
- Department of Industrial Biotechnology, Atta ur Rahman School of Applied Biosciences, National University of Science and Technology, Islamabad, Pakistan
| | - Sammia Rehman
- Department of Industrial Biotechnology, Atta ur Rahman School of Applied Biosciences, National University of Science and Technology, Islamabad, Pakistan
| | - Amjad Ali
- Department of Industrial Biotechnology, Atta ur Rahman School of Applied Biosciences, National University of Science and Technology, Islamabad, Pakistan
| | - Saadia Andleeb
- Department of Industrial Biotechnology, Atta ur Rahman School of Applied Biosciences, National University of Science and Technology, Islamabad, Pakistan
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DeAngelis CM, Saul-McBeth J, Matson JS. Vibrio responses to extracytoplasmic stress. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:511-521. [PMID: 30246498 DOI: 10.1111/1758-2229.12693] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/11/2018] [Accepted: 09/12/2018] [Indexed: 06/08/2023]
Abstract
A critical factor for bacterial survival in any environment is the ability to sense and respond appropriately to any stresses encountered. This is especially important for bacteria that inhabit environments that are constantly changing, or for those that inhabit more than one biological niche. Vibrio species are unique in that they are aquatic organisms, and must adapt to ever-changing temperatures, salinity levels and nutrient concentrations. In addition, many species of Vibrio colonize other organisms, and must also deal with components of the host immune response. Vibrio infections of humans and other organisms have become more common in recent years, due to increasing water temperatures in many parts of the world. Therefore, understanding how these ubiquitous marine bacteria adapt to their changing environments is of importance. In this review, we discuss some of the ways that Vibrios sense and respond to the variety of stresses that negatively affect the bacterial cell envelope. Specifically, we will focus on what is currently known about the σE response, the Cpx response and the contributions of OmpU to extracytoplasmic stress relief.
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Affiliation(s)
- Cara M DeAngelis
- Department of Medical Microbiology and Immunology, University of Toledo Medical School, Toledo, OH, USA
| | - Jessica Saul-McBeth
- Department of Medical Microbiology and Immunology, University of Toledo Medical School, Toledo, OH, USA
| | - Jyl S Matson
- Department of Medical Microbiology and Immunology, University of Toledo Medical School, Toledo, OH, USA
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Cyclo-(l-Phe-l-Pro), a Quorum-Sensing Signal of Vibrio vulnificus, Induces Expression of Hydroperoxidase through a ToxR-LeuO-HU-RpoS Signaling Pathway To Confer Resistance against Oxidative Stress. Infect Immun 2018; 86:IAI.00932-17. [PMID: 29914931 PMCID: PMC6105893 DOI: 10.1128/iai.00932-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 06/06/2018] [Indexed: 12/17/2022] Open
Abstract
Vibrio vulnificus, an opportunistic human pathogen, produces cyclo-(l-Phe-l-Pro) (cFP), which serves as a signaling molecule controlling the ToxR-dependent expression of innate bacterial genes, and also as a virulence factor eliciting pathogenic effects on human cells by enhancing intracellular reactive oxygen species levels. We found that cFP facilitated the protection of V. vulnificus against hydrogen peroxide. At a concentration of 1 mM, cFP enhanced the level of the transcriptional regulator RpoS, which in turn induced expression of katG, encoding hydroperoxidase I, an enzyme that detoxifies H2O2 to overcome oxidative stress. We found that cFP upregulated the transcription of the histone-like proteins vHUα and vHUβ through the cFP-dependent regulator LeuO. LeuO binds directly to upstream regions of vhuA and vhuB to enhance transcription. vHUα and vHUβ then enhance the level of RpoS posttranscriptionally by stabilizing the mRNA. This cFP-mediated ToxR-LeuO-vHUαβ-RpoS pathway also upregulates genes known to be members of the RpoS regulon, suggesting that cFP acts as a cue for the signaling pathway responsible for both the RpoS and the LeuO regulons. Taken together, this study shows that cFP plays an important role as a virulence factor, as well as a signal for the protection of the cognate pathogen.
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Thompson LR, Nikolakakis K, Pan S, Reed J, Knight R, Ruby EG. Transcriptional characterization of Vibrio fischeri during colonization of juvenile Euprymna scolopes. Environ Microbiol 2017; 19:1845-1856. [PMID: 28152560 PMCID: PMC5409853 DOI: 10.1111/1462-2920.13684] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/24/2017] [Accepted: 01/29/2017] [Indexed: 11/30/2022]
Abstract
The marine bacterium Vibrio fischeri is the monospecific symbiont of the Hawaiian bobtail squid, Euprymna scolopes, and the establishment of this association involves a number of signaling pathways and transcriptional responses between both partners. We report here the first full RNA-Seq dataset representing host-associated V. fischeri cells from colonized juvenile E. scolopes, as well as comparative transcriptomes under both laboratory and simulated marine planktonic conditions. These data elucidate the broad transcriptional changes that these bacteria undergo during the early stages of symbiotic colonization. We report several previously undescribed and unexpected transcriptional responses within the early stages of this symbiosis, including gene expression patterns consistent with biochemical stresses inside the host, and metabolic patterns distinct from those reported in associations with adult animals. Integration of these transcriptional data with a recently developed metabolic model of V. fischeri provides us with a clearer picture of the metabolic state of symbionts within the juvenile host, including their possible carbon sources. Taken together, these results expand our understanding of the early stages of the squid-vibrio symbiosis, and more generally inform the transcriptional responses underlying the activities of marine microbes during host colonization.
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Affiliation(s)
- Luke R Thompson
- Department of Pediatrics, University of California, San Diego, CA, USA
| | - Kiel Nikolakakis
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, WI, USA
| | - Shu Pan
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, WI, USA
| | - Jennifer Reed
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, WI, USA
| | - Rob Knight
- Department of Pediatrics, University of California, San Diego, CA, USA
| | - Edward G Ruby
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, WI, USA
- Pacific Biosciences Research Center, University of Hawaii, Manoa, HI, USA
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Rotation of Vibrio fischeri Flagella Produces Outer Membrane Vesicles That Induce Host Development. J Bacteriol 2016; 198:2156-65. [PMID: 27246572 DOI: 10.1128/jb.00101-16] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/20/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Using the squid-vibrio association, we aimed to characterize the mechanism through which Vibrio fischeri cells signal morphogenesis of the symbiotic light-emitting organ. The symbiont releases two cell envelope molecules, peptidoglycan (PG) and lipopolysaccharide (LPS) that, within 12 h of light organ colonization, act in synergy to trigger normal tissue development. Recent work has shown that outer membrane vesicles (OMVs) produced by V. fischeri are sufficient to induce PG-dependent morphogenesis; however, the mechanism(s) of OMV release by these bacteria has not been described. Like several genera of both beneficial and pathogenic bacteria, V. fischeri cells elaborate polar flagella that are enclosed by an extension of the outer membrane, whose function remains unclear. Here, we present evidence that along with the well-recognized phenomenon of blebbing from the cell's surface, rotation of this sheathed flagellum also results in the release of OMVs. In addition, we demonstrate that most of the development-inducing LPS is associated with these OMVs and that the presence of the outer membrane protein OmpU but not the LPS O antigen on these OMVs is important in triggering normal host development. These results also present insights into a possible new mechanism of LPS release by pathogens with sheathed flagella. IMPORTANCE Determining the function(s) of sheathed flagella in bacteria has been challenging, because no known mutation results only in the loss of this outer membrane-derived casing. Nevertheless, the presence of a sheathed flagellum in such host-associated genera as Vibrio, Helicobacter, and Brucella has led to several proposed functions, including physical protection of the flagella and masking of their immunogenic flagellins. Using the squid-vibrio light organ symbiosis, we demonstrate another role, that of V. fischeri cells require rotating flagella to induce apoptotic cell death within surface epithelium, which is a normal step in the organ's development. Further, we present evidence that this rotation releases apoptosis-triggering lipopolysaccharide in the form of outer membrane vesicles. Such release may also occur by pathogens but with different outcomes for the host.
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12
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Augimeri RV, Varley AJ, Strap JL. Establishing a Role for Bacterial Cellulose in Environmental Interactions: Lessons Learned from Diverse Biofilm-Producing Proteobacteria. Front Microbiol 2015; 6:1282. [PMID: 26635751 PMCID: PMC4646962 DOI: 10.3389/fmicb.2015.01282] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 10/31/2015] [Indexed: 01/21/2023] Open
Abstract
Bacterial cellulose (BC) serves as a molecular glue to facilitate intra- and inter-domain interactions in nature. Biosynthesis of BC-containing biofilms occurs in a variety of Proteobacteria that inhabit diverse ecological niches. The enzymatic and regulatory systems responsible for the polymerization, exportation, and regulation of BC are equally as diverse. Though the magnitude and environmental consequences of BC production are species-specific, the common role of BC-containing biofilms is to establish close contact with a preferred host to facilitate efficient host-bacteria interactions. Universally, BC aids in attachment, adherence, and subsequent colonization of a substrate. Bi-directional interactions influence host physiology, bacterial physiology, and regulation of BC biosynthesis, primarily through modulation of intracellular bis-(3'→5')-cyclic diguanylate (c-di-GMP) levels. Depending on the circumstance, BC producers exhibit a pathogenic or symbiotic relationship with plant, animal, or fungal hosts. Rhizobiaceae species colonize plant roots, Pseudomonadaceae inhabit the phyllosphere, Acetobacteriaceae associate with sugar-loving insects and inhabit the carposphere, Enterobacteriaceae use fresh produce as vehicles to infect animal hosts, and Vibrionaceae, particularly Aliivibrio fischeri, colonize the light organ of squid. This review will highlight the diversity of the biosynthesis and regulation of BC in nature by discussing various examples of Proteobacteria that use BC-containing biofilms to facilitate host-bacteria interactions. Through discussion of current data we will establish new directions for the elucidation of BC biosynthesis, its regulation and its ecophysiological roles.
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Affiliation(s)
| | | | - Janice L. Strap
- Molecular Microbial Biochemistry Laboratory, Faculty of Science, University of Ontario Institute of TechnologyOshawa, ON, Canada
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13
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Chavez-Dozal A, Gorman C, Nishiguchi MK. Proteomic and metabolomic profiles demonstrate variation among free-living and symbiotic vibrio fischeri biofilms. BMC Microbiol 2015; 15:226. [PMID: 26494154 PMCID: PMC4619220 DOI: 10.1186/s12866-015-0560-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 10/08/2015] [Indexed: 11/11/2022] Open
Abstract
Background A number of bacterial species are capable of growing in various life history modes that enable their survival and persistence in both planktonic free-living stages as well as in biofilm communities. Mechanisms contributing to either planktonic cell or biofilm persistence and survival can be carefully delineated using multiple differential techniques (e.g., genomics and transcriptomics). In this study, we present both proteomic and metabolomic analyses of Vibrio fischeri biofilms, demonstrating the potential for combined differential studies for elucidating life-history switches important for establishing the mutualism through biofilm formation and host colonization. Methods The study used a metabolomics/proteomics or “meta-proteomics” approach, referring to the combined protein and metabolic data analysis that bridges the gap between phenotypic changes (planktonic cell to biofilm formation) with genotypic changes (reflected in protein/metabolic profiles). Our methods used protein shotgun construction, followed by liquid chromatography coupled with mass spectrometry (LC-MS) detection and quantification for both free-living and biofilm forming V. fischeri. Results We present a time-resolved picture of approximately 100 proteins (2D-PAGE and shotgun proteomics) and 200 metabolites that are present during the transition from planktonic growth to community biofilm formation. Proteins involved in stress response, DNA repair damage, and transport appeared to be highly expressed during the biofilm state. In addition, metabolites detected in biofilms correspond to components of the exopolysaccharide (EPS) matrix (sugars and glycerol-derived). Alterations in metabolic enzymes were paralleled by more pronounced changes in concentration of intermediates from the glycolysis pathway as well as several amino acids. Conclusions This combined analysis of both types of information (proteins, metabolites) has provided a more complete picture of the biochemical processes of biofilm formation and what determines the switch between the two life history strategies. The reported findings have broad implications for Vibrio biofilm ecology, and mechanisms for successful survival in the host and environment. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0560-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alba Chavez-Dozal
- Department of Biology, New Mexico State University, Box 30001, MSC 3AF, Las Cruces, NM, 88003-8001, USA.
| | - Clayton Gorman
- Department of Biology, New Mexico State University, Box 30001, MSC 3AF, Las Cruces, NM, 88003-8001, USA.
| | - Michele K Nishiguchi
- Department of Biology, New Mexico State University, Box 30001, MSC 3AF, Las Cruces, NM, 88003-8001, USA.
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Har JY, Helbig T, Lim JH, Fernando SC, Reitzel AM, Penn K, Thompson JR. Microbial diversity and activity in the Nematostella vectensis holobiont: insights from 16S rRNA gene sequencing, isolate genomes, and a pilot-scale survey of gene expression. Front Microbiol 2015; 6:818. [PMID: 26388838 PMCID: PMC4557100 DOI: 10.3389/fmicb.2015.00818] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/27/2015] [Indexed: 01/08/2023] Open
Abstract
We have characterized the molecular and genomic diversity of the microbiota of the starlet sea anemone Nematostella vectensis, a cnidarian model for comparative developmental and functional biology and a year-round inhabitant of temperate salt marshes. Molecular phylogenetic analysis of 16S rRNA gene clone libraries revealed four ribotypes associated with N. vectensis at multiple locations and times. These associates include two novel ribotypes within the ε-Proteobacterial order Campylobacterales and the Spirochetes, respectively, each sharing <85% identity with cultivated strains, and two γ-Proteobacterial ribotypes sharing >99% 16S rRNA identity with Endozoicomonas elysicola and Pseudomonas oleovorans, respectively. Species-specific PCR revealed that these populations persisted in N. vectensis asexually propagated under laboratory conditions. cDNA indicated expression of the Campylobacterales and Endozoicomonas 16S rRNA in anemones from Sippewissett Marsh, MA. A collection of bacteria from laboratory raised N. vectensis was dominated by isolates from P. oleovorans and Rhizobium radiobacter. Isolates from field-collected anemones revealed an association with Limnobacter and Stappia isolates. Genomic DNA sequencing was carried out on 10 cultured bacterial isolates representing field- and laboratory-associates, i.e., Limnobacter spp., Stappia spp., P. oleovorans and R. radiobacter. Genomes contained multiple genes identified as virulence (host-association) factors while S. stellulata and L. thiooxidans genomes revealed pathways for mixotrophic sulfur oxidation. A pilot metatranscriptome of laboratory-raised N. vectensis was compared to the isolate genomes and indicated expression of ORFs from L. thiooxidans with predicted functions of motility, nutrient scavenging (Fe and P), polyhydroxyalkanoate synthesis for carbon storage, and selective permeability (porins). We hypothesize that such activities may mediate acclimation and persistence of bacteria in a N. vectensis holobiont defined by both internal and external gradients of chemicals and nutrients in a dynamic coastal habitat.
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Affiliation(s)
- Jia Y Har
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Tim Helbig
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Ju H Lim
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Samodha C Fernando
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Adam M Reitzel
- Department of Biological Sciences, University of North Carolina at Charlotte Charlotte, NC, USA
| | - Kevin Penn
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Janelle R Thompson
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA
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15
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Vibrio cholerae pathogen from the freshwater-cultured whiteleg shrimp Penaeus vannamei and control with Bdellovibrio bacteriovorus. J Invertebr Pathol 2015; 130:13-20. [DOI: 10.1016/j.jip.2015.06.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 06/16/2015] [Accepted: 06/22/2015] [Indexed: 11/20/2022]
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16
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Abstract
To cause the diarrheal disease cholera, Vibrio cholerae must effectively colonize the small intestine. In order to do so, the bacterium needs to successfully travel through the stomach and withstand the presence of agents such as bile and antimicrobial peptides in the intestinal lumen and mucus. The bacterial cells penetrate the viscous mucus layer covering the epithelium and attach and proliferate on its surface. In this review, we discuss recent developments and known aspects of the early stages of V. cholerae intestinal colonization and highlight areas that remain to be fully understood. We propose mechanisms and postulate a model that covers some of the steps that are required in order for the bacterium to efficiently colonize the human host. A deeper understanding of the colonization dynamics of V. cholerae and other intestinal pathogens will provide us with a variety of novel targets and strategies to avoid the diseases caused by these organisms.
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Affiliation(s)
- Salvador Almagro-Moreno
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- * E-mail:
| | - Kali Pruss
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Ronald K. Taylor
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
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17
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Ondrey JM, Visick KL. Engineering Vibrio fischeri for Inducible Gene Expression. Open Microbiol J 2014; 8:122-9. [PMID: 25408777 PMCID: PMC4235076 DOI: 10.2174/1874285801408010122] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 09/19/2014] [Accepted: 09/29/2014] [Indexed: 11/30/2022] Open
Abstract
The marine bacterium Vibrio fischeri serves as a model organism for a variety of natural phenomena, including symbiotic host colonization. The ease with which the V. fischeri genome can be manipulated contributes greatly to our ability to identify the factors involved in these phenomena. Here, we have adapted genetic tools for use in V. fischeri to promote our ability to conditionally control the expression of genes of interest. Specifically, we modified the commonly used mini-Tn5 transposon to contain an outward-facing, LacI-repressible/IPTG-inducible promoter, and inserted the lacI gene into the V. fischeri chromosome. Used together, these tools permit the identification and induction of genes that control specific phenotypes. To validate this approach, we identified IPTG-controllable motility mutants. We anticipate that the ability to randomly insert an inducible promoter into the genome of V. fischeri will advance our understanding of various aspects of the physiology of this microbe.
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Affiliation(s)
- Jakob M Ondrey
- Department of Microbiology and Immunology, Health Sciences Division, Loyola University Chicago, 2160 S. First Avenue Building 105 Room 3936, Maywood, IL 60153, USA
| | - Karen L Visick
- Department of Microbiology and Immunology, Health Sciences Division, Loyola University Chicago, 2160 S. First Avenue Building 105 Room 3936, Maywood, IL 60153, USA
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18
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Schleicher TR, VerBerkmoes NC, Shah M, Nyholm SV. Colonization state influences the hemocyte proteome in a beneficial squid-Vibrio symbiosis. Mol Cell Proteomics 2014; 13:2673-86. [PMID: 25038065 DOI: 10.1074/mcp.m113.037259] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The squid Euprymna scolopes and the luminescent bacterium Vibrio fischeri form a highly specific beneficial light organ symbiosis. Not only does the host have to select V. fischeri from the environment, but it must also prevent subsequent colonization by non-symbiotic microorganisms. Host macrophage-like hemocytes are believed to play a role in mediating the symbiosis with V. fischeri. Previous studies have shown that the colonization state of the light organ influences the host's hemocyte response to the symbiont. To further understand the molecular mechanisms behind this process, we used two quantitative mass-spectrometry-based proteomic techniques, isobaric tags for relative and absolute quantification (iTRAQ) and label-free spectral counting, to compare and quantify the adult hemocyte proteomes from colonized (sym) and uncolonized (antibiotic-treated/cured) squid. Overall, iTRAQ allowed for the quantification of 1,024 proteins with two or more peptides. Thirty-seven unique proteins were determined to be significantly different between sym and cured hemocytes (p value < 0.05), with 20 more abundant proteins and 17 less abundant in sym hemocytes. The label-free approach resulted in 1,241 proteins that were identified in all replicates. Of 185 unique proteins present at significantly different amounts in sym hemocytes (as determined by spectral counting), 92 were more abundant and 93 were less abundant. Comparisons between iTRAQ and spectral counting revealed that 30 of the 37 proteins quantified via iTRAQ exhibited trends similar to those identified by the label-free method. Both proteomic techniques mutually identified 16 proteins that were significantly different between the two groups of hemocytes (p value < 0.05). The presence of V. fischeri in the host light organ influenced the abundance of proteins associated with the cytoskeleton, adhesion, lysosomes, proteolysis, and the innate immune response. These data provide evidence that colonization by V. fischeri alters the hemocyte proteome and reveals proteins that may be important for maintaining host-symbiont specificity.
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Affiliation(s)
- Tyler R Schleicher
- From the ‡Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, 06269
| | - Nathan C VerBerkmoes
- §Chemical Biology Division, New England Biolabs Inc., Ipswich, Massachusetts, 01938
| | - Manesh Shah
- ‖Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee, 37996
| | - Spencer V Nyholm
- From the ‡Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, 06269;
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19
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Heath-Heckman EAC, Gillette AA, Augustin R, Gillette MX, Goldman WE, McFall-Ngai MJ. Shaping the microenvironment: evidence for the influence of a host galaxin on symbiont acquisition and maintenance in the squid-Vibrio symbiosis. Environ Microbiol 2014; 16:3669-82. [PMID: 24802887 DOI: 10.1111/1462-2920.12496] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 02/13/2014] [Accepted: 02/24/2014] [Indexed: 12/15/2022]
Abstract
Most bacterial species make transitions between habitats, such as switching from free living to symbiotic niches. We provide evidence that a galaxin protein, EsGal1, of the squid Euprymna scolopes participates in both: (i) selection of the specific partner Vibrio fischeri from the bacterioplankton during symbiosis onset and, (ii) modulation of V. fischeri growth in symbiotic maintenance. We identified two galaxins in transcriptomic databases and showed by quantitative reverse-transcriptase polymerase chain reaction that one (esgal1) was dominant in the light organ. Further, esgal1 expression was upregulated by symbiosis, a response that was partially achieved with exposure to symbiont cell-envelope molecules. Confocal immunocytochemistry of juvenile animals localized EsGal1 to the apical surfaces of light-organ epithelia and surrounding mucus, the environment in which V. fischeri cells aggregate before migration into the organ. Growth assays revealed that one repeat of EsGal1 arrested growth of Gram-positive bacterial cells, which represent the cell type first 'winnowed' during initial selection of the symbiont. The EsGal1-derived peptide also significantly decreased the growth rate of V. fischeri in culture. Further, when animals were exposed to an anti-EsGal1 antibody, symbiont population growth was significantly increased. These data provide a window into how hosts select symbionts from a rich environment and govern their growth in symbiosis.
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20
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Altura MA, Heath-Heckman EAC, Gillette A, Kremer N, Krachler AM, Brennan C, Ruby EG, Orth K, McFall-Ngai MJ. The first engagement of partners in the Euprymna scolopes-Vibrio fischeri symbiosis is a two-step process initiated by a few environmental symbiont cells. Environ Microbiol 2013; 15:2937-50. [PMID: 23819708 DOI: 10.1111/1462-2920.12179] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 05/06/2013] [Accepted: 06/02/2013] [Indexed: 11/26/2022]
Abstract
We studied the Euprymna scolopes-Vibrio fischeri symbiosis to characterize, in vivo and in real time, the transition between the bacterial partner's free-living and symbiotic life styles. Previous studies using high inocula demonstrated that environmental V. fischeri cells aggregate during a 3 h period in host-shed mucus along the light organ's superficial ciliated epithelia. Under lower inoculum conditions, similar to the levels of symbiont cells in the environment, this interaction induces haemocyte trafficking into these tissues. Here, in experiments simulating natural conditions, microscopy revealed that at 3 h following first exposure, only ∼ 5 V. fischeri cells aggregated on the organ surface. These cells associated with host cilia and induced haemocyte trafficking. Symbiont viability was essential and mutants defective in symbiosis initiation and/or production of certain surface features, including the Mam7 protein, which is implicated in host cell attachment of V. cholerae, associated normally with host cilia. Studies with exopolysaccharide mutants, which are defective in aggregation, suggest a two-step process of V. fischeri cell engagement: association with host cilia followed by aggregation, i.e. host cell-symbiont interaction with subsequent symbiont-symbiont cell interaction. Taken together, these data provide a new model of early partner engagement, a complex model of host-symbiont interaction with exquisite sensitivity.
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Affiliation(s)
- Melissa A Altura
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Amani Gillette
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Natacha Kremer
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Anne-Marie Krachler
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Caitlin Brennan
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Edward G Ruby
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Margaret J McFall-Ngai
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, USA
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21
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Johnson CN. Fitness factors in vibrios: a mini-review. MICROBIAL ECOLOGY 2013; 65:826-851. [PMID: 23306394 DOI: 10.1007/s00248-012-0168-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/13/2012] [Indexed: 06/01/2023]
Abstract
Vibrios are Gram-negative curved bacilli that occur naturally in marine, estuarine, and freshwater systems. Some species include human and animal pathogens, and some vibrios are necessary for natural systems, including the carbon cycle and osmoregulation. Countless in vivo and in vitro studies have examined the interactions between vibrios and their environment, including molecules, cells, whole animals, and abiotic substrates. Many studies have characterized virulence factors, attachment factors, regulatory factors, and antimicrobial resistance factors, and most of these factors impact the organism's fitness regardless of its external environment. This review aims to identify common attributes among factors that increase fitness in various environments, regardless of whether the environment is an oyster, a rabbit, a flask of immortalized mammalian cells, or a planktonic chitin particle. This review aims to summarize findings published thus far to encapsulate some of the basic similarities among the many vibrio fitness factors and how they frame our understanding of vibrio ecology. Factors representing these similarities include hemolysins, capsular polysaccharides, flagella, proteases, attachment factors, type III secretion systems, chitin binding proteins, iron acquisition systems, and colonization factors.
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Affiliation(s)
- Crystal N Johnson
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA, USA.
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22
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Abstract
Biofilms are multicellular communities of bacteria attached to a surface and embedded in a protective matrix. In many cases, the signals that induce biofilm formation are unknown. Here, we report that biofilm formation by the marine bacterium Vibrio fischeri can be induced by the addition of arabinose to LBS (Luria-Bertani-salt), a tryptone-based medium. Growth of cells in the presence of 0.2% arabinose, but not other sugars, induced the production of a pellicle at the air/liquid interfaces of static cultures. V. fischeri failed to grow on arabinose as the sole carbon source, suggesting that pellicle production did not occur as a result of increased growth, but experiments using the acid/base indicator phenol red suggested that V. fischeri may partially metabolize arabinose. Pellicle production was independent of the syp polysaccharide locus but was altered upon disruption of the bcs cellulose locus. Through a screen for mutants defective for pellicle production, we found that loss of motility disrupted the formation of the arabinose-induced pellicle. Among the ∼20 mutants that retained motility were strains with insertions in a putative msh pilus locus and a strain with a defect in yidK, which is involved in galactose catabolism. Mutants with the msh gene disrupted grew poorly in the presence of arabinose, while the yidK mutant appeared to be "blind" to the presence of arabinose. Finally, arabinose impaired symbiotic colonization by V. fischeri. This work thus identifies a novel signal and new pathways involved in control of biofilm formation by V. fischeri.
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Zhao P, Huang J, Wang XH. Comparative Proteomics of two Vibrio anguillarum Serotype O1 Strains with Different Virulence Phenotypes. Curr Microbiol 2012; 65:262-71. [DOI: 10.1007/s00284-012-0156-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Accepted: 05/20/2012] [Indexed: 11/29/2022]
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Schleicher TR, Nyholm SV. Characterizing the host and symbiont proteomes in the association between the Bobtail squid, Euprymna scolopes, and the bacterium, Vibrio fischeri. PLoS One 2011; 6:e25649. [PMID: 21998678 PMCID: PMC3187790 DOI: 10.1371/journal.pone.0025649] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 09/07/2011] [Indexed: 11/26/2022] Open
Abstract
The beneficial symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium, Vibrio fischeri, provides a unique opportunity to study host/microbe interactions within a natural microenvironment. Colonization of the squid light organ by V. fischeri begins a lifelong association with a regulated daily rhythm. Each morning the host expels an exudate from the light organ consisting of 95% of the symbiont population in addition to host hemocytes and shed epithelial cells. We analyzed the host and symbiont proteomes of adult squid exudate and surrounding light organ epithelial tissue using 1D- and 2D-polyacrylamide gel electrophoresis and multidimensional protein identification technology (MudPIT) in an effort to understand the contribution of both partners to the maintenance of this association. These proteomic analyses putatively identified 1581 unique proteins, 870 proteins originating from the symbiont and 711 from the host. Identified host proteins indicate a role of the innate immune system and reactive oxygen species (ROS) in regulating the symbiosis. Symbiont proteins detected enhance our understanding of the role of quorum sensing, two-component signaling, motility, and detoxification of ROS and reactive nitrogen species (RNS) inside the light organ. This study offers the first proteomic analysis of the symbiotic microenvironment of the adult light organ and provides the identification of proteins important to the regulation of this beneficial association.
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Affiliation(s)
- Tyler R. Schleicher
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Spencer V. Nyholm
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, United States of America
- * E-mail:
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Guerrero-Ferreira RC, Nishiguchi MK. Differential gene expression in bacterial symbionts from loliginid squids demonstrates variation between mutualistic and environmental niches. ENVIRONMENTAL MICROBIOLOGY REPORTS 2010; 2:514-523. [PMID: 20680094 PMCID: PMC2911791 DOI: 10.1111/j.1758-2229.2009.00077.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Luminescent bacteria (gamma-Proteobacteria: Vibrionaceae) are found in complex bilobed light organs of both sepiolid and loliginid squids (Mollusca: Cephalopoda). Despite the existence of multiple strain colonization between Vibrio bacteria and loliginid squids, specificity at the genus level still exists and may influence interactions between symbiotic and free-living stages of the symbiont. The environmentally transmitted behaviour of Vibrio symbionts bestows a certain degree of recognition that exists prior and subsequent to the colonization process. Therefore, we identified bacterial genes required for successful colonization of loliginid light organs by examining transcripts solely expressed in either the light organ or free-living stages. Selective capture of transcribed sequences (SCOTS) was used to differentiate genes expressed by the same bacterium when thriving in two different environments (i.e. loliginid light organs and seawater). Genes specific for squid light organs included vulnibactin synthetase, outer membrane protein W and dihydroxy dehydratase, which have been associated with the maintenance of bacterial host associations in other systems. In contrast, genes that were solely expressed in the free-living condition consisted of transcripts recognized as important factors for bacterial survival in the environment. These transcripts included genes for methyl accepting chemotaxis proteins, arginine decarboxylase and chitinase. These results provide valuable information regarding mechanisms determining specificity, establishment, and maintenance of bacteria-squid associations.
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Abstract
The perpetuation of symbioses through host generations relies on symbiont transmission. Horizontally transmitted symbionts are taken up from the environment anew by each host generation, and vertically transmitted symbionts are most often transferred through the female germ line. Mixed modes also exist. In this Review we describe the journey of symbionts from the initial contact to their final residence. We provide an overview of the molecular mechanisms that mediate symbiont attraction and accumulation, interpartner recognition and selection, as well as symbiont confrontation with the host immune system. We also discuss how the two main transmission modes shape the evolution of the symbiotic partners.
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Affiliation(s)
- Monika Bright
- University of Vienna, Department of Marine Biology, Althanstrasse 14, A-1090 Vienna, Austria.
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Chaston J, Goodrich-Blair H. Common trends in mutualism revealed by model associations between invertebrates and bacteria. FEMS Microbiol Rev 2010; 34:41-58. [PMID: 19909347 PMCID: PMC2794943 DOI: 10.1111/j.1574-6976.2009.00193.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mutually beneficial interactions between microorganisms and animals are a conserved and ubiquitous feature of biotic systems. In many instances animals, including humans, are dependent on their microbial associates for nutrition, defense, or development. To maintain these vital relationships, animals have evolved processes that ensure faithful transmission of specific microbial symbionts between generations. Elucidating mechanisms of transmission and symbiont specificity has been aided by the study of experimentally tractable invertebrate animals with diverse and highly evolved associations with microorganisms. Here, we review several invertebrate model systems that contribute to our current understanding of symbiont transmission, recognition, and specificity. Although the details of transmission and symbiont selection vary among associations, comparisons of diverse mutualistic associations are revealing a number of common themes, including restriction of symbiont diversity during transmission and glycan-lectin interactions during partner selection and recruitment.
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Affiliation(s)
- John Chaston
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
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Campbell J, Lin Q, Geske GD, Blackwell HE. New and unexpected insights into the modulation of LuxR-type quorum sensing by cyclic dipeptides. ACS Chem Biol 2009; 4:1051-9. [PMID: 19928886 DOI: 10.1021/cb900165y] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Quorum sensing (QS) is under the control of N-acylated l-homoserine lactones (AHLs) and their cognate receptors (LuxR-type proteins) in Gram-negative bacteria and plays a major role in mediating host-bacteria interactions by these species. Certain cyclic dipeptides (2,5-diketopiperazines, DKPs) have been isolated from bacteria and reported to activate or inhibit LuxR-type proteins in AHL biosensor strains, albeit at significantly higher concentrations than native lactones. These reports have prompted the proposal that DKPs represent a new class of QS signals and potentially even interspecies or interkingdom signals; their mechanisms of action and physiological relevance, however, remain unknown. Here, we describe a library of synthetic DKPs that was designed to (1) determine the structural features necessary for LuxR-type protein activation and inhibition and (2) probe their mechanisms of action. These DKPs, along with several previously reported natural DKPs, were screened in bacterial reporter gene assays. In contrast to previous reports, the native DKPs failed to exhibit either antagonistic or agonistic activities in these assays. However, non-natural halogenated cyclo(l-Pro-l-Phe) derivatives were capable of inhibiting luminescence in Vibrio fischeri. Interestingly, additional experiments revealed that these DKPs do not compete with the natural lactone signal, OHHL, to inhibit luminescence. Together, these data suggest that DKPs are not QS signals in the bacteria examined in this study. Although these compounds can influence QS-regulated outcomes, we contend that they do not do so through direct interaction with LuxR-type proteins. This work serves to refine the lexicon of naturally occurring QS signals used by Gram-negative bacteria.
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Affiliation(s)
- Jennifer Campbell
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322
| | - Qi Lin
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322
| | - Grant D. Geske
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322
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Pilonieta MC, Erickson KD, Ernst RK, Detweiler CS. A protein important for antimicrobial peptide resistance, YdeI/OmdA, is in the periplasm and interacts with OmpD/NmpC. J Bacteriol 2009; 191:7243-52. [PMID: 19767429 PMCID: PMC2786563 DOI: 10.1128/jb.00688-09] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 09/10/2009] [Indexed: 01/02/2023] Open
Abstract
Antimicrobial peptides (AMPs) kill or prevent the growth of microbes. AMPs are made by virtually all single and multicellular organisms and are encountered by bacteria in diverse environments, including within a host. Bacteria use sensor-kinase systems to respond to AMPs or damage caused by AMPs. Salmonella enterica deploys at least three different sensor-kinase systems to modify gene expression in the presence of AMPs: PhoP-PhoQ, PmrA-PmrB, and RcsB-RcsC-RcsD. The ydeI gene is regulated by the RcsB-RcsC-RcsD pathway and encodes a 14-kDa predicted oligosaccharide/oligonucleotide binding-fold (OB-fold) protein important for polymyxin B resistance in broth and also for virulence in mice. We report here that ydeI is additionally regulated by the PhoP-PhoQ and PmrA-PmrB sensor-kinase systems, which confer resistance to cationic AMPs by modifying lipopolysaccharide (LPS). ydeI, however, is not important for known LPS modifications. Two independent biochemical methods found that YdeI copurifies with OmpD/NmpC, a member of the trimeric beta-barrel outer membrane general porin family. Genetic analysis indicates that ompD contributes to polymyxin B resistance, and both ydeI and ompD are important for resistance to cathelicidin antimicrobial peptide, a mouse AMP produced by multiple cell types and expressed in the gut. YdeI localizes to the periplasm, where it could interact with OmpD. A second predicted periplasmic OB-fold protein, YgiW, and OmpF, another general porin, also contribute to polymyxin B resistance. Collectively, the data suggest that periplasmic OB-fold proteins can interact with porins to increase bacterial resistance to AMPs.
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Affiliation(s)
- M. Carolina Pilonieta
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, Colorado 80309, University of Maryland-Baltimore, Department of Microbial Pathogenesis, School of Dentistry, Baltimore, Maryland 21201
| | - Kimberly D. Erickson
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, Colorado 80309, University of Maryland-Baltimore, Department of Microbial Pathogenesis, School of Dentistry, Baltimore, Maryland 21201
| | - Robert K. Ernst
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, Colorado 80309, University of Maryland-Baltimore, Department of Microbial Pathogenesis, School of Dentistry, Baltimore, Maryland 21201
| | - Corrella S. Detweiler
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, Colorado 80309, University of Maryland-Baltimore, Department of Microbial Pathogenesis, School of Dentistry, Baltimore, Maryland 21201
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OpnS, an outer membrane porin of Xenorhabdus nematophila, confers a competitive advantage for growth in the insect host. J Bacteriol 2009; 191:5471-9. [PMID: 19465651 DOI: 10.1128/jb.00148-09] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The gammaproteobacterium Xenorhabdus nematophila engages in a mutualistic association with an entomopathogenic nematode and also functions as a pathogen toward different insect hosts. We studied the role of the growth-phase-regulated outer membrane protein OpnS in host interactions. OpnS was shown to be a 16-stranded beta-barrel porin. opnS was expressed during growth in insect hemolymph and expression was elevated as the cell density increased. When wild-type and opnS deletion strains were coinjected into insects, the wild-type strain was predominantly recovered from the insect cadaver. Similarly, an opnS-complemented strain outcompeted the DeltaopnS strain. Coinjection of the wild-type and DeltaopnS strains together with uncolonized nematodes into insects resulted in nematode progeny that were almost exclusively colonized with the wild-type strain. Likewise, nematode progeny recovered after coinjection of a mixture of nematodes carrying either the wild-type or DeltaopnS strain were colonized by the wild-type strain. In addition, the DeltaopnS strain displayed a competitive growth defect when grown together with the wild-type strain in insect hemolymph but not in defined culture medium. The DeltaopnS strain displayed increased sensitivity to antimicrobial compounds, suggesting that deletion of OpnS affected the integrity of the outer membrane. These findings show that the OpnS porin confers a competitive advantage for the growth and/or the survival of X. nematophila in the insect host and provides a new model for studying the biological relevance of differential regulation of porins in a natural host environment.
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Nyholm SV, Stewart JJ, Ruby EG, McFall-Ngai MJ. Recognition between symbiotic Vibrio fischeri and the haemocytes of Euprymna scolopes. Environ Microbiol 2009; 11:483-93. [PMID: 19196278 PMCID: PMC2652691 DOI: 10.1111/j.1462-2920.2008.01788.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The light organ crypts of the squid Euprymna scolopes permit colonization exclusively by the luminous bacterium Vibrio fischeri. Because the crypt interior remains in contact with seawater, the squid must not only foster the specific symbiosis, but also continue to exclude other bacteria. Investigation of the role of the innate immune system in these processes revealed that macrophage-like haemocytes isolated from E. scolopes recognized and phagocytosed V. fischeri less than other closely related bacterial species common to the host's environment. Interestingly, phagocytes isolated from hosts that had been cured of their symbionts bound five times more V. fischeri cells than those from uncured hosts. No such change in the ability to bind other species of bacteria was observed, suggesting that the host adapts specifically to V. fischeri. Deletion of the gene encoding OmpU, the major outer membrane protein of V. fischeri, increased binding by haemocytes from uncured animals to the level observed for haemocytes from cured animals. Co-incubation with wild-type V. fischeri reduced this binding, suggesting that they produce a factor that complements the mutant's defect. Analyses of the phagocytosis of bound cells by fluorescence-activated cell sorting indicated that once binding to haemocytes had occurred, V. fischeri cells are phagocytosed as effectively as other bacteria. Thus, discrimination by this component of the squid immune system occurs at the level of haemocyte binding, and this response: (i) is modified by previous exposure to the symbiont and (ii) relies on outer membrane and/or secreted components of the symbionts. These data suggest that regulation of host haemocyte binding by the symbiont may be one of many factors that contribute to specificity in this association.
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Affiliation(s)
- Spencer V. Nyholm
- Kewalo Marine Laboratory, 41 Ahui St., University of Hawaii, Honolulu, HI 96813, USA
| | - Jennifer J. Stewart
- Kewalo Marine Laboratory, 41 Ahui St., University of Hawaii, Honolulu, HI 96813, USA
| | - Edward G. Ruby
- Kewalo Marine Laboratory, 41 Ahui St., University of Hawaii, Honolulu, HI 96813, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA
| | - Margaret J. McFall-Ngai
- Kewalo Marine Laboratory, 41 Ahui St., University of Hawaii, Honolulu, HI 96813, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA
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Abstract
The recent development and application of molecular genetics to the symbionts of invertebrate animal species have advanced our knowledge of the biochemical communication that occurs between the host and its bacterial symbionts. In particular, the ability to manipulate these associations experimentally by introducing genetic variants of the symbionts into naive hosts has allowed the discovery of novel colonization mechanisms and factors. In addition, the role of the symbionts in inducing normal host development has been revealed, and its molecular basis described. In this Review, I discuss many of these developments, focusing on what has been discovered in five well-understood model systems.
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Affiliation(s)
- Edward G Ruby
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Room 5203 Microbial Sciences Building, 1550 Linden Drive, Madison, Wisconsin 53706-1521, USA.
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Vydryakova GA, Bondar' VS. Location of lectin exhibiting specificity for N-acetyl-D-galactosamine in cells of the symbiotic marine bacteria Photobacterium phosphoreum. DOKL BIOCHEM BIOPHYS 2008; 420:155-7. [PMID: 18680915 DOI: 10.1134/s1607672908030150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- G A Vydryakova
- Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036 Russia
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Adin DM, Visick KL, Stabb EV. Identification of a cellobiose utilization gene cluster with cryptic beta-galactosidase activity in Vibrio fischeri. Appl Environ Microbiol 2008; 74:4059-69. [PMID: 18487409 PMCID: PMC2446528 DOI: 10.1128/aem.00190-08] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Accepted: 05/07/2008] [Indexed: 11/20/2022] Open
Abstract
Cellobiose utilization is a variable trait that is often used to differentiate members of the family Vibrionaceae. We investigated how Vibrio fischeri ES114 utilizes cellobiose and found a cluster of genes required for growth on this beta-1,4-linked glucose disaccharide. This cluster includes genes annotated as a phosphotransferase system II (celA, celB, and celC), a glucokinase (celK), and a glucosidase (celG). Directly downstream of celCBGKA is celI, which encodes a LacI family regulator that represses cel transcription in the absence of cellobiose. When the celCBGKAI gene cluster was transferred to cellobiose-negative strains of Vibrio and Photobacterium, the cluster conferred the ability to utilize cellobiose. Genomic analyses of naturally cellobiose-positive Vibrio species revealed that V. salmonicida has a homolog of the celCBGKAI cluster, but V. vulnificus does not. Moreover, bioinformatic analyses revealed that CelG and CelK share the greatest homology with glucosidases and glucokinases in the phylum Firmicutes. These observations suggest that distinct genes for cellobiose utilization have been acquired by different lineages within the family Vibrionaceae. In addition, the loss of the celI regulator, but not the structural genes, attenuated the ability of V. fischeri to compete for colonization of its natural host, Euprymna scolopes, suggesting that repression of the cel gene cluster is important in this symbiosis. Finally, we show that the V. fischeri cellobioase (CelG) preferentially cleaves beta-d-glucose linkages but also cleaves beta-d-galactose-linked substrates such as 5-bromo-4-chloro-3-indolyl-beta-d-galactoside (X-gal), a finding that has important implications for the use of lacZ as a marker or reporter gene in V. fischeri.
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Affiliation(s)
- Dawn M Adin
- Department of Microbiology, University of Georgia, 1000 Cedar Street, Athens, GA 30602, USA
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Mao Z, Yu L, You Z, Wei Y, Liu Y. Cloning, expression and immunogenicty analysis of five outer membrane proteins of Vibrio parahaemolyticus zj2003. FISH & SHELLFISH IMMUNOLOGY 2007; 23:567-75. [PMID: 17451968 DOI: 10.1016/j.fsi.2007.01.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 01/10/2007] [Accepted: 01/10/2007] [Indexed: 05/15/2023]
Abstract
Genes of five outer membrane proteins of Vibrio parahaemolyticus zj2003, including OmpW, OmpV, OmpK, OmpU and TolC, were cloned and expressed as N-terminal His(6)-tagged proteins in Escherichia coli. The recombinant fusion proteins were purified with nickel chelate affinity chromatography. To analyze the immunogenicity of these proteins, large yellow croaker (Pseudosciaena crocea) were immunized by intraperitoneal injection. Antibody response was assessed by method of enzyme-linked immunosorbent assay. Titres to all five recombinant proteins increased during 4 to 8 weeks post immunization, within the range of log 2 values of 5.75 to 10.8. Recorded relative survival percent (RPS) of the vaccinated groups varied from 80% to 90%, while 10 fish in control group all died. Western blot tests were undertaken with the serum of survival fish after experimental infection. Except for recombinant TolC, the other four recombinant proteins were recognized by the serum. It is indicated that four outer membrane proteins of V. parahaemolyticus zj2003, including OmpW, OmpV, OmpU and OmpK, are immunogenic during in vivo infection, which would be of some significance in developing efficient vaccine in aquaculture. This is the first report of successful vaccination against V. parahaemolyticus with purified recombinant outer membrane proteins.
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Affiliation(s)
- Zhijuan Mao
- College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang Province 310027, China
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36
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Expression and purification of two major outer membrane proteins from Vibrio alginolyticus. World J Microbiol Biotechnol 2007. [DOI: 10.1007/s11274-007-9463-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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37
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Lo RYC, Sorensen LS. The outer membrane protein OmpA of Mannheimia haemolytica A1 is involved in the binding of fibronectin. FEMS Microbiol Lett 2007; 274:226-31. [PMID: 17608694 DOI: 10.1111/j.1574-6968.2007.00830.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
An enzyme-linked immunosorbent assay using bovine fibronectin as the substrate was used to demonstrate that Mannheimia haemolytica A1 binds to fibronectin. This binding to fibronectin was specific as no binding was observed with bovine fibrinogen. The binding to fibronectin was not observed if the M. haemolytica A1 cells were pretreated with trypsin or proteinase K, suggesting that it involved a protein molecule on the cell surface. Interestingly, the fibronectin-binding activity was found to be higher in an acapsular mutant compared with its parent strain. The fibronectin-binding protein was shown to be present in the outer membrane fraction of M. haemolytica A1. A 45 kDa outer membrane protein that binds to fibronectin was identified by Far-Western immunoblot analysis. This protein was purified and subjected to MS matrix-assisted laser desorption ionization time-of-flight analysis. The results identified it to be outer membrane OmpA based on comparison with the M. haemolytica A1 genomic sequence.
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Affiliation(s)
- Reggie Y C Lo
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
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38
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Goo SY, Lee HJ, Kim WH, Han KL, Park DK, Lee HJ, Kim SM, Kim KS, Lee KH, Park SJ. Identification of OmpU of Vibrio vulnificus as a fibronectin-binding protein and its role in bacterial pathogenesis. Infect Immun 2006; 74:5586-94. [PMID: 16988233 PMCID: PMC1594942 DOI: 10.1128/iai.00171-06] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus is a pathogenic bacterium that causes gastroenteritis and primary septicemia. To identify factors involved in microbial adherence to the host cells, we investigated bacterial proteins capable of binding to fibronectin, one of the main components comprised of the extracellular matrix of mammalian cells. A protein of approximately 35 kDa was purified from the extracts of V. vulnificus by its property to bind to immobilized fibronectin. This protein was identified as OmpU, one of the major outer membrane proteins of V. vulnificus. In binding assays using immobilized fibronectin, the number of ompU mutant cells bound to fibronectin was only 4% of that of wild-type cells bound to fibronectin. In addition, the exogenous addition of antibodies against OmpU resulted in a decreased ability of wild-type V. vulnificus to adhere to fibronectin. The ompU mutant was also defective in its adherence to RGD tripeptide (5% of the adherence of the wild type to RGD), cytoadherence to HEp-2 cells (7% of the adherence of the wild type to HEp-2), cytotoxicity to cell cultures (39% of the cytotoxicity of the wild type), and mortality in mice (10-fold increase in the 50% lethal dose). The ompU mutant complemented with the intact ompU gene restored its abilities for adherence to fibronectin, RGD tripeptide, and HEp-2 cells; cytotoxicity to HEp-2 cells; and mouse lethality. This study indicates that OmpU is an important virulence factor involved in the adherence of V. vulnificus to the host cells.
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Affiliation(s)
- Sung Young Goo
- Department of Parasitology, Yonsei University School of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752, Korea
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39
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40
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Geszvain K, Visick KL. Roles of bacterial regulators in the symbiosis between Vibrio fischeri and Euprymna scolopes. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2006; 41:277-90. [PMID: 16623398 DOI: 10.1007/3-540-28221-1_13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Affiliation(s)
- Kati Geszvain
- Dept. Microbiology and Immunology, Loyola University Chicago, 2160 S. First Ave. Bldg. 105, Maywood, IL 60153, USA
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41
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Park DK, Lee KE, Baek CH, Kim IH, Kwon JH, Lee WK, Lee KH, Kim BS, Choi SH, Kim KS. Cyclo(Phe-Pro) modulates the expression of ompU in Vibrio spp. J Bacteriol 2006; 188:2214-21. [PMID: 16513751 PMCID: PMC1428137 DOI: 10.1128/jb.188.6.2214-2221.2006] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2005] [Accepted: 11/07/2005] [Indexed: 12/13/2022] Open
Abstract
Vibrio vulnificus was found to produce a chemical that induced the expression of Vibrio fischeri lux genes. Electron spray ionization-mass spectrometry and 1H nuclear magnetic resonance analyses indicated that the compound was cyclo(L-Phe-L-Pro) (cFP). The compound was produced at a maximal level when cell cultures reached the onset of stationary phase. Sodium dodecyl sulfate-polyacrylamide gel analysis of the total proteins of V. vulnificus indicated that expression of OmpU was enhanced by exogenously added synthetic or purified cFP. A toxR-null mutant failed to express ompU despite the addition of cFP. The related Vibrio spp. V. cholerae, V. parahaemolyticus, and V. harveyi also produced cFP, which induced the expression of their own ompU genes. cFP also enhanced the expression in V. cholerae of the ctx genes, which are known to be regulated by ToxR. Our results suggest that cFP is a signal molecule controlling the expression of genes important for the pathogenicity of Vibrio spp.
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Affiliation(s)
- Dae-Kyun Park
- Department of Life Science, Sogang University, Sinsoo-Dong 1, Mapo-Gu, Seoul 121-742, South Korea
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Dunn AK, Millikan DS, Adin DM, Bose JL, Stabb EV. New rfp- and pES213-derived tools for analyzing symbiotic Vibrio fischeri reveal patterns of infection and lux expression in situ. Appl Environ Microbiol 2006; 72:802-10. [PMID: 16391121 PMCID: PMC1352280 DOI: 10.1128/aem.72.1.802-810.2006] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Accepted: 10/11/2005] [Indexed: 11/20/2022] Open
Abstract
Genetically altered or tagged Vibrio fischeri strains can be observed in association with their mutualistic host Euprymna scolopes, providing powerful experimental approaches for studying this symbiosis. Two limitations to such in situ analyses are the lack of suitably stable plasmids and the need for a fluorescent tag that can be used in tandem with green fluorescent protein (GFP). Vectors previously used in V. fischeri contain the p15A replication origin; however, we found that this replicon is not stable during growth in the host and is retained by fewer than 20% of symbionts within a day after infection. In contrast, derivatives of V. fischeri plasmid pES213 were retained by approximately 99% of symbionts even 3 days after infection. We therefore constructed pES213-derived shuttle vectors with a variety of selectable and visual markers. To include a visual tag that can be used in conjunction with GFP, we compared seven variants of the DsRed2 red fluorescent protein (RFP): mRFP1, tdimer2(12), DsRed.T3, DsRed.T4, DsRed.M1, DsRed.T3_S4T, and DsRed.T3(DNT). The last variant was brightest, displaying >20-fold more fluorescence than DsRed2 in V. fischeri. RFP expression did not detectably affect the fitness of V. fischeri, and cells were readily visualized in combination with GFP-expressing cells in mixed infections. Interestingly, even when inocula were dense enough that most E. scolopes hatchlings were infected by two strains, there was little mixing of the strains in the light organ crypts. We also used constitutive RFP in combination with the luxICDABEG promoter driving expression of GFP to visualize the spatial and temporal induction of this bioluminescence operon during symbiotic infection. Our results demonstrate the utility of pES213-based vectors and RFP for in situ experimental approaches in studies of the V. fischeri-E. scolopes symbiosis.
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Affiliation(s)
- Anne K Dunn
- University of Georgia, Department of Microbiology, 828 Biological Sciences, Athens, GA 30602, USA
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Yip ES, Grublesky BT, Hussa EA, Visick KL. A novel, conserved cluster of genes promotes symbiotic colonization and sigma-dependent biofilm formation by Vibrio fischeri. Mol Microbiol 2005; 57:1485-98. [PMID: 16102015 DOI: 10.1111/j.1365-2958.2005.04784.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Vibrio fischeri is the exclusive symbiont residing in the light organ of the squid Euprymna scolopes. To understand the genetic requirements for this association, we searched a library of V. fischeri transposon insertion mutants for those that failed to colonize E. scolopes. We identified four mutants that exhibited severe defects in initiating colonization. Sequence analysis revealed that the strains contained insertions in four different members of a cluster of 21 genes oriented in the same direction. The predicted gene products are similar to proteins involved in capsule, exopolysaccharide or lipopolysaccharide biosynthesis, including six putative glycosyltransferases. We constructed mutations in five additional genes and found that they also were required for symbiosis. Therefore, we have termed this region syp, for symbiosis polysaccharide. Homologous clusters also exist in Vibrio parahaemolyticus and Vibrio vulnificus, and thus these genes may represent a common mechanism for promoting bacteria-host interactions. Using lacZ reporter fusions, we observed that transcription of the syp genes did not occur under standard laboratory conditions, but could be induced by multicopy expression of sypG, which encodes a response regulator with a predicted sigma54 interaction domain. This induction depended on sigma54, as a mutation in rpoN abolished syp transcription. Primer extension analysis supported the use of putative sigma54 binding sites upstream of sypA, sypI and sypM as promoters. Finally, we found that multicopy expression of sypG resulted in robust biofilm formation. This work thus reveals a novel group of genes that V. fischeri controls through a sigma54-dependent response regulator and uses to promote symbiotic colonization.
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Affiliation(s)
- Emily S Yip
- Department of Microbiology and Immunology, Loyola University Chicago, 2160 S. First Ave. Bldg. 105, Maywood, IL 60153, USA
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Dunn AK, Martin MO, Stabb EV. Characterization of pES213, a small mobilizable plasmid from Vibrio fischeri. Plasmid 2005; 54:114-34. [PMID: 16122560 DOI: 10.1016/j.plasmid.2005.01.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Revised: 01/17/2005] [Accepted: 01/24/2005] [Indexed: 10/25/2022]
Abstract
Most Vibrio fischeri strains isolated from the Euprymna scolopes light organ carry plasmids, often including both a large (>40kb) plasmid, and one or more small (<12kb) plasmids. The large plasmids share homology with pES100, which is the lone plasmid in V. fischeri type strain ES114. pES100 appears to encode a conjugative system similar to that on plasmid R721. The small plasmids lack extensive similarity to pES100, but they almost always occur in cells that also harbor a large plasmid resembling pES100. We found that many or all of these small plasmids share homology with pES213, a plasmid in strain ES213. We determined the 5501-bp pES213 sequence and generated selectable antibiotic resistance encoding pES213 derivatives, which enabled us to examine replication, retention, and transfer in V. fischeri. An 863-bp fragment of pES213 with features characteristic of theta-type replicons conferred replication without requiring any pES213 open reading frame (ORF). We estimated that pES213 derivatives were maintained at 9.4 copies per genome, which corresponds well with a model of random plasmid segregation to daughter cells and the approximately 10(-4) per generation frequency of plasmid loss. pES213 derivatives mobilized between V. fischeri strains at frequencies up to approximately 10(-4) in culture and in the host, apparently by employing the pES100 conjugative apparatus. pES213 carries two homologs of the putative pES100 origin of transfer (oriT), and V. fischeri strains lacking the pES100 conjugative relaxase, including a relaxase mutant, failed to serve as donors for transmission of pES213 derivatives. In other systems, genes directing conjugative transfer can function in trans to oriT, so it was noteworthy that ORFs adjacent to oriT, VFB51 in pES100 and traYZ in pES213, enhanced transfer 100- to 1000-fold when provided in cis. We also identified and disrupted the V. fischeri recA gene. RecA was not required for stable pES213 replication but surprisingly was required in donors for efficient transfer of pES213 derivatives. These studies provide an explanation for the prevalence and co-occurrence of pES100- and pES213-type plasmids, illuminate novel elements of pES213 mobilization, and provide the foundation for new genetic tools in V. fischeri.
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Affiliation(s)
- Anne K Dunn
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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45
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Affiliation(s)
- Spencer V Nyholm
- Department of Pathology, Stanford University, School of Medicine, Palo Alto, California 94305, USA
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46
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Mathur J, Waldor MK. The Vibrio cholerae ToxR-regulated porin OmpU confers resistance to antimicrobial peptides. Infect Immun 2004; 72:3577-83. [PMID: 15155667 PMCID: PMC415678 DOI: 10.1128/iai.72.6.3577-3583.2004] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BPI (bactericidal/permeability-increasing) is a potent antimicrobial protein that was recently reported to be expressed as a surface protein on human gastrointestinal tract epithelial cells. In this study, we investigated the resistance of Vibrio cholerae, a small-bowel pathogen that causes cholera, to a BPI-derived peptide, P2. Unlike in Escherichia coli and Salmonella enterica serovar Typhimurium, resistance to P2 in V. cholerae was not dependent on the BipA GTPase. Instead, we found that ToxR, the master regulator of V. cholerae pathogenicity, controlled resistance to P2 by regulating the production of the outer membrane protein OmpU. Both toxR and ompU mutants were at least 100-fold more sensitive to P2 than were wild-type cells. OmpU also conferred resistance to polymyxin B sulfate, suggesting that this porin may impart resistance to cationic antibacterial proteins via a common mechanism. Studies of stationary-phase cells revealed that the ToxR-repressed porin OmpT may also contribute to P2 resistance. Finally, although the mechanism of porin-mediated resistance to antimicrobial peptides remains elusive, our data suggest that the BPI peptide sensitivity of OmpU-deficient V. cholerae is not attributable to a generally defective outer membrane.
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Affiliation(s)
- Jyoti Mathur
- Department of Immunology, Sackler School of Biomedical Sciences, Tufts University School of Medicine, and Howard Hughes Medical Institute, Boston, Massachusetts 02111, USA
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McCann J, Stabb EV, Millikan DS, Ruby EG. Population dynamics of Vibrio fischeri during infection of Euprymna scolopes. Appl Environ Microbiol 2004; 69:5928-34. [PMID: 14532046 PMCID: PMC201191 DOI: 10.1128/aem.69.10.5928-5934.2003] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The luminous bacterium Vibrio fischeri colonizes a specialized light-emitting organ within its squid host, Euprymna scolopes. Newly hatched juvenile squid must acquire their symbiont from ambient seawater, where the bacteria are present at low concentrations. To understand the population dynamics of V. fischeri during colonization more fully, we used mini-Tn7 transposons to mark bacteria with antibiotic resistance so that the growth of their progeny could be monitored. When grown in culture, there was no detectable metabolic burden on V. fischeri cells carrying the transposon, which inserts in single copy in a specific intergenic region of the V. fischeri genome. Strains marked with mini-Tn7 also appeared to be equivalent to the wild type in their ability to infect and multiply within the host during coinoculation experiments. Studies of the early stages of colonization suggested that only a few bacteria became associated with symbiotic tissue when animals were exposed for a discrete period (3 h) to an inoculum of V. fischeri cells equivalent to natural population levels; nevertheless, all these hosts became infected. When three differentially marked strains of V. fischeri were coincubated with juvenile squid, the number of strains recovered from an individual symbiotic organ was directly dependent on the size of the inoculum. Further, these results indicated that, when exposed to low numbers of V. fischeri, the host may become colonized by only one or a few bacterial cells, suggesting that symbiotic infection is highly efficient.
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Affiliation(s)
- Jessica McCann
- Pacific Biomedical Research Center, University of Hawaii, Honolulu, Hawaii 96813, USA
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Millikan DS, Ruby EG. FlrA, a sigma54-dependent transcriptional activator in Vibrio fischeri, is required for motility and symbiotic light-organ colonization. J Bacteriol 2003; 185:3547-57. [PMID: 12775692 PMCID: PMC156232 DOI: 10.1128/jb.185.12.3547-3557.2003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Flagellum-mediated motility of Vibrio fischeri is an essential factor in the bacterium's ability to colonize its host, the Hawaiian squid Euprymna scolopes. To begin characterizing the nature of the flagellar regulon, we have cloned a gene, designated flrA, from V. fischeri that encodes a putative sigma(54)-dependent transcriptional activator. Genetic arrangement of the flrA locus in V. fischeri is similar to motility master-regulator operons of Vibrio cholerae and Vibrio parahaemolyticus. In addition, examination of regulatory regions of a number of flagellar operons in V. fischeri revealed apparent sigma(54) recognition motifs, suggesting that the flagellar regulatory hierarchy is controlled by a similar mechanism to that described in V. cholerae. However, in contrast to its closest known relatives, flrA mutant strains of V. fischeri ES114 were completely abolished in swimming capability. Although flrA provided in trans restored motility to the flrA mutant, the complemented strain was unable to reach wild-type levels of symbiotic colonization in juvenile squid, suggesting a possible role for the proper expression of FlrA in regulating symbiotic colonization factors in addition to those required for motility. Comparative RNA arbitrarily primed PCR analysis of the flrA mutant and its wild-type parent revealed several differentially expressed transcripts. These results define a regulon that includes both flagellar structural genes and other genes apparently not involved in flagellum elaboration or function. Thus, the transcriptional activator FlrA plays an essential role in regulating motility, and apparently in modulating other symbiotic functions, in V. fischeri.
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Affiliation(s)
- Deborah S Millikan
- Pacific Biomedical Research Center, University of Hawaii, Honolulu, Hawaii 96813, USA
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Wang SY, Lauritz J, Jass J, Milton DL. Role for the major outer-membrane protein from Vibrio anguillarum in bile resistance and biofilm formation. MICROBIOLOGY (READING, ENGLAND) 2003; 149:1061-1071. [PMID: 12686648 DOI: 10.1099/mic.0.26032-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Vibrio anguillarum, a fish pathogen, produces a 38 kDa major outer-membrane porin, which may be involved in environmental adaptation. The gene encoding the 38 kDa porin was cloned and deleted. The deduced protein sequence was 75 % identical to that of the major outer-membrane protein (OMP), OmpU, from Vibrio cholerae. LacZ expression from an ompU : : lacZ transcriptional gene fusion was increased 1.5-fold in the presence of bile salts and was decreased 50- to 100-fold in a toxR mutant compared to that in the wild-type, showing that ompU expression is positively regulated by ToxR and induced by bile salts. Similar to a toxR mutant, an ompU mutant showed a slight decrease in motility, an increased sensitivity to bile salts and a thicker biofilm with better surface area coverage compared to that of the wild-type. When ompU was expressed under a ToxR-independent promoter in the toxR mutant, the phenotypes for bile resistance and biofilm formation, but not motility were complemented to that of the wild-type. In rainbow trout, the ompU mutant showed wild-type virulence via immersion into infected seawater and intraperitoneal injection. The ompU mutant produced two colony morphologies: opaque, which did not grow at 0.2 % bile, and translucent, which grew at 2 % bile. The translucent ompU mutant strain produced a second major OMP that was induced by bile. All ompU mutants showed variations in the amount and length of smooth LPS. In V. anguillarum, OmpU is not required for virulence, possibly due to a second OMP also critical for resistance to bile; however, outside of the fish host, OmpU limits the progression of biofilm formation.
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Affiliation(s)
- Su-Yan Wang
- Department of Molecular Biology, Umeå University, S-901 87 Umeå, Sweden
| | - Johan Lauritz
- Department of Molecular Biology, Umeå University, S-901 87 Umeå, Sweden
| | - Jana Jass
- Department of Molecular Biology, Umeå University, S-901 87 Umeå, Sweden
| | - Debra L Milton
- Department of Molecular Biology, Umeå University, S-901 87 Umeå, Sweden
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Lupp C, Hancock REW, Ruby EG. The Vibrio fischeri sapABCDF locus is required for normal growth, both in culture and in symbiosis. Arch Microbiol 2002; 179:57-65. [PMID: 12471505 DOI: 10.1007/s00203-002-0502-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2002] [Revised: 10/02/2002] [Accepted: 10/14/2002] [Indexed: 11/24/2022]
Abstract
Inactivation of the sapABCDF genes results in a loss of virulence in several bacterial pathogens of animals and plants. The role of this locus in the growth physiology of Vibrio fischeri, and in the symbiotic colonization of the squid Euprymna scolopes was investigated. In rich medium, a V. fischeri sapA insertion mutant grew at only 85% the rate of its wild-type parent. While a similar effect has been attributed to a potassium-transport defect in sap mutants of enteric bacteria, the V. fischeri mutant grew more slowly regardless of the potassium concentration of the medium. Similarly, the growth-rate defect was independent of the source of either carbon, nitrogen, or phosphorous, indicating that the V. fischeri sap genes do not encode functions required for the transport of a specific form of any of these nutrients. Finally, while a delay in colonizing the nascent light organ of the squid could be accounted for by the lower growth rate of the mutant, a small but statistically significant reduction in its final population size in the host, but not in medium, suggests that the sap genes play another role in the symbiosis. All of these phenotypic defects could be genetically complemented in trans by the sapABCDF genes, but not by the sapA gene alone, indicating that the insertion in sapA is polar to the four downstream genes in the locus. Thus, while the sap locus is important to the normal growth of V. fischeri, it plays different physiological roles in growth and tissue colonization than it does in enteric pathogens.
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Affiliation(s)
- Claudia Lupp
- University of Hawaii, Kewalo Marine Laboratory, 41 Ahui Street, Honolulu, HI 96813, USA
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