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Sherik M, Eves R, Guo S, Lloyd CJ, Klose KE, Davies PL. Sugar-binding and split domain combinations in repeats-in-toxin adhesins from Vibrio cholerae and Aeromonas veronii mediate cell-surface recognition and hemolytic activities. mBio 2024; 15:e0229123. [PMID: 38171003 PMCID: PMC10865825 DOI: 10.1128/mbio.02291-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
Abstract
Many pathogenic Gram-negative bacteria use repeats-in-toxin adhesins for colonization and biofilm formation. In the cholera agent Vibrio cholerae, flagellar-regulated hemagglutinin A (FrhA) enables these functions. Using bioinformatic analysis, a sugar-binding domain was identified in FrhA adjacent to a domain of unknown function. AlphaFold2 indicated the boundaries of both domains to be slightly shorter than previously predicted and assisted in the recognition of the unknown domain as a split immunoglobulin-like fold that can assist in projecting the sugar-binding domain toward its target. The AlphaFold2-predicted structure is in excellent agreement with the molecular envelope obtained from small-angle X-ray scattering analysis of a recombinant construct spanning the sugar-binding and unknown domains. This two-domain construct was probed by glycan micro-array screening and showed binding to mammalian fucosylated glycans, some of which are characteristic erythrocyte markers and intestinal cell epitopes. Isothermal titration calorimetry further showed the construct-bound l-fucose with a Kd of 21 µM. Strikingly, this recombinant protein construct bound and lysed erythrocytes in a concentration-dependent manner, and its hemolytic activity was blocked by the addition of l-fucose. A protein ortholog construct from Aeromonas veronii was also produced and showed a similar glycan-binding pattern, binding affinity, erythrocyte-binding, and hemolytic activities. As demonstrated here with Hep-2 cells, fucose-based inhibitors of this sugar-binding domain can potentially be developed to block colonization by V. cholerae and other pathogenic bacteria that share this adhesin domain.IMPORTANCEThe bacterium, Vibrio cholerae, which causes cholera, uses an adhesion protein to stick to human cells and begin the infection process. One part of this adhesin protein binds to a particular sugar, fucose, on the surface of the target cells. This binding can lead to colonization and killing of the cells by the bacteria. Adding l-fucose to the bacteria before they bind to the human cells can prevent attachment and has promise as a preventative drug to protect against cholera.
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Affiliation(s)
- Mustafa Sherik
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Robert Eves
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Shuaiqi Guo
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Cameron J. Lloyd
- South Texas Center for Emerging Infectious Diseases and Department of Molecular Microbiology and Immunology, University of Texas San Antonio, San Antonio, Texas, USA
| | - Karl E. Klose
- South Texas Center for Emerging Infectious Diseases and Department of Molecular Microbiology and Immunology, University of Texas San Antonio, San Antonio, Texas, USA
| | - Peter L. Davies
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
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Kempnich MW, Sison-Mangus MP. Presence and abundance of bacteria with the Type VI secretion system in a coastal environment and in the global oceans. PLoS One 2020; 15:e0244217. [PMID: 33351849 PMCID: PMC7755280 DOI: 10.1371/journal.pone.0244217] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/04/2020] [Indexed: 01/13/2023] Open
Abstract
Marine bacteria employ various strategies to maintain their competitive advantage over others in a mixed community. The use of Type VI Secretion Systems (T6SS), a protein secretion apparatus used as a molecular weapon for interbacterial competition and eukaryotic interactions, is one of the competitive strategies that is least studied among heterotrophic bacteria living in the water column. To get an insight into the temporal and spatial distribution of bacteria with T6SS in this portion of the marine environment, we examine the presence and abundance of T6SS-bearing bacteria at both local and global scales through the use of metagenome data from water samples obtained from the coast of Monterey Bay and the TARA Oceans project. We also track the abundance of T6SS-harboring bacteria through a two-year time series of weekly water samples in the same coastal site to examine the environmental factors that may drive their presence and abundance. Among the twenty-one T6SS-bearing bacterial genera examined, we found several genera assume a particle-attached lifestyle, with only a few genera having a free-living lifestyle. The abundance of T6SS-harboring bacteria in both niches negatively correlates with the abundance of autotrophs. Globally, we found that T6SS genes are much more abundant in areas with low biological productivity. Our data suggest that T6SS-harboring bacteria tend to be abundant spatially and temporally when organic resources are limited. This ecological study agrees with the patterns observed from several in vitro studies; that T6SS could be an adaptive strategy employed by heterotrophic bacteria to obtain nutrients or reduce competition when resources are in limited quantity.
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Affiliation(s)
- Michael W. Kempnich
- Department of Ocean Sciences and Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Marilou P. Sison-Mangus
- Department of Ocean Sciences and Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, California, United States of America
- * E-mail:
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Kochanowsky RM, Bradshaw C, Forlastro I, Stock SP. Xenorhabdus bovienii strain jolietti uses a type 6 secretion system to kill closely related Xenorhabdus strains. FEMS Microbiol Ecol 2020; 96:fiaa073. [PMID: 32558899 PMCID: PMC7353953 DOI: 10.1093/femsec/fiaa073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 04/21/2020] [Indexed: 01/25/2023] Open
Abstract
Xenorhabdus bovienii strain jolietti (XBJ) is a Gram-negative bacterium that interacts with several organisms as a part of its life cycle. It is a beneficial symbiont of nematodes, a potent pathogen of a wide range of soil-dwelling insects and also has the ability to kill soil- and insect-associated microbes. Entomopathogenic Steinernema nematodes vector XBJ into insects, releasing the bacteria into the insect body cavity. There, XBJ produce a variety of insecticidal toxins and antimicrobials. XBJ's genome also encodes two separate Type Six Secretion Systems (T6SSs), structures that allow bacteria to inject specific proteins directly into other cells, but their roles in the XBJ life cycle are mostly unknown. To probe the function of these T6SSs, we generated mutant strains lacking the key structural protein Hcp from each T6SS and assessed phenotypes related to different parts of XBJ's life cycle. Here we demonstrate that one of the T6SSs is more highly expressed in in vitro growth conditions and has antibacterial activity against other Xenorhabdus strains, and that the two T6SSs have a redundant role in biofilm formation.
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Affiliation(s)
- Rebecca M Kochanowsky
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 1117 E. Lowell St., Tucson, AZ 85721, USA
- Center for Insect Science, University of Arizona, 1007 E. Lowell St., Tucson, AZ 85721, USA
| | - Christine Bradshaw
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 1117 E. Lowell St., Tucson, AZ 85721, USA
| | - Isabel Forlastro
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 1117 E. Lowell St., Tucson, AZ 85721, USA
| | - S Patricia Stock
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 1117 E. Lowell St., Tucson, AZ 85721, USA
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Guillemette R, Ushijima B, Jalan M, Häse CC, Azam F. Insight into the resilience and susceptibility of marine bacteria to T6SS attack by Vibrio cholerae and Vibrio coralliilyticus. PLoS One 2020; 15:e0227864. [PMID: 31990915 PMCID: PMC6986712 DOI: 10.1371/journal.pone.0227864] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 12/31/2019] [Indexed: 11/19/2022] Open
Abstract
The type VI secretion system (T6SS) is a nanomachine capable of killing adjacent microbial cells in a contact-dependent manner. Due to limited studies, relatively little is known about the range of marine bacteria that are susceptible to T6SS attack. Here, 15 diverse marine bacterial isolates from the phyla Bacteroidetes and Ɣ-Proteobacteria were challenged against the marine bacterium and human pathogen, Vibrio cholerae, which has a well described T6SS. V. cholerae killed several of the tested Ɣ-Proteobacteria, including members of the orders Vibrionales, Alteromonadales, Oceanospirillales, and Pseudomonadales. In contrast, V. cholerae co-existed with multiple Bacteroidetes and Ɣ-Proteobacteria isolates, but was killed by Vibrio coralliilyticus. Follow-up experiments revealed that five V. coralliilyticus strains, including known coral and shellfish pathogens survived the T6SS challenge and killed V. cholerae. By using predicted protein comparisons and mutagenesis, we conclude that V. coralliilyticus protected itself in the challenge by using its own T6SS to kill V. cholerae. This study provides valuable insight into the resilience and susceptibility of marine bacteria to the V. cholerae T6SS, and provides the first evidence for a functional T6SS in V. coralliilyticus, both of which have implications for human and ocean health.
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Affiliation(s)
- Ryan Guillemette
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, San Diego, CA, United States of America
| | - Blake Ushijima
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States of America
| | - Mihika Jalan
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, San Diego, CA, United States of America
| | - Claudia C. Häse
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States of America
| | - Farooq Azam
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, San Diego, CA, United States of America
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Wang R, Seyedsayamdost MR. Opinion: Hijacking exogenous signals to generate new secondary metabolites during symbiotic interactions. Nat Rev Chem 2017. [DOI: 10.1038/s41570-017-0021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Leisner JJ, Jørgensen NOG, Middelboe M. Predation and selection for antibiotic resistance in natural environments. Evol Appl 2016; 9:427-34. [PMID: 26989434 PMCID: PMC4778110 DOI: 10.1111/eva.12353] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 12/21/2015] [Indexed: 12/01/2022] Open
Abstract
Genes encoding resistance to antibiotics appear, like the antibiotics themselves, to be ancient, originating long before the rise of the era of anthropogenic antibiotics. However, detailed understanding of the specific biological advantages of antibiotic resistance in natural environments is still lacking, thus limiting our efforts to prevent environmental influx of resistance genes. Here, we propose that antibiotic-resistant cells not only evade predation from antibiotic producers but also take advantage of nutrients released from cells that are killed by the antibiotic-producing bacteria. Thus, predation is potentially an important mechanism for driving antibiotic resistance during slow or stationary phase of growth when nutrients are deprived. This adds to explain the ancient nature and widespread occurrence of antibiotic resistance in natural environments unaffected by anthropogenic antibiotics. In particular, we suggest that nutrient-poor environments including indoor environments, for example, clean rooms and intensive care units may serve as a reservoir and source for antibiotic-producing as well as antibiotic-resistant bacteria.
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Affiliation(s)
- Jørgen J. Leisner
- Department of Veterinary Disease BiologyFaculty of Health and Medical SciencesUniversity of CopenhagenFrederiksbergDenmark
| | - Niels O. G. Jørgensen
- Department of Plant and Environmental SciencesFaculty of ScienceUniversity of CopenhagenFrederiksbergDenmark
| | - Mathias Middelboe
- Department of BiologyMarine Biological SectionFaculty of ScienceUniversity of CopenhagenHelsingørDenmark
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Keane R, Berleman J. The predatory life cycle of Myxococcus xanthus. Microbiology (Reading) 2016; 162:1-11. [DOI: 10.1099/mic.0.000208] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Ryan Keane
- Department of Biology, Saint Mary's College, Moraga, CA 94556, USA
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - James Berleman
- Department of Biology, Saint Mary's College, Moraga, CA 94556, USA
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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Mallon CA, Elsas JDV, Salles JF. Microbial Invasions: The Process, Patterns, and Mechanisms. Trends Microbiol 2015; 23:719-729. [DOI: 10.1016/j.tim.2015.07.013] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Revised: 07/20/2015] [Accepted: 07/31/2015] [Indexed: 01/20/2023]
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Boucher Y, Orata FD, Alam M. The out-of-the-delta hypothesis: dense human populations in low-lying river deltas served as agents for the evolution of a deadly pathogen. Front Microbiol 2015; 6:1120. [PMID: 26539168 PMCID: PMC4609888 DOI: 10.3389/fmicb.2015.01120] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/28/2015] [Indexed: 12/03/2022] Open
Abstract
Cholera is a diarrheal disease that has changed the history of mankind, devastating the world with seven pandemics from 1817 to the present day. Although there is little doubt in the causative agent of these pandemics being Vibrio cholerae of the O1 serogroup, where, when, and how this pathogen emerged is not well understood. V. cholerae is a ubiquitous coastal species that likely existed for tens of thousands of years. However, the evolution of a strain capable of causing a large-scale epidemic is likely more recent historically. Here, we propose that the unique human and physical geography of low-lying river deltas made it possible for an environmental bacterium to evolve into a deadly human pathogen. Such areas are often densely populated and salt intrusion in drinking water frequent. As V. cholerae is most abundant in brackish water, its favored environment, it is likely that coastal inhabitants would regularly ingest the bacterium and release it back in the environment. This creates a continuous selection pressure for V. cholerae to adapt to life in the human gut.
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Affiliation(s)
- Yan Boucher
- Department of Biological Sciences, University of Alberta , Edmonton, AB, Canada
| | - Fabini D Orata
- Department of Biological Sciences, University of Alberta , Edmonton, AB, Canada
| | - Munirul Alam
- Centre for Communicable Diseases, International Centre for Diarrhoeal Disease Research , Bangladesh (ICDDR,B), Dhaka, Bangladesh
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Destoumieux-Garzón D, Duperthuy M, Vanhove AS, Schmitt P, Wai SN. Resistance to Antimicrobial Peptides in Vibrios. Antibiotics (Basel) 2014; 3:540-63. [PMID: 27025756 PMCID: PMC4790380 DOI: 10.3390/antibiotics3040540] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 09/25/2014] [Accepted: 10/08/2014] [Indexed: 12/19/2022] Open
Abstract
Vibrios are associated with a broad diversity of hosts that produce antimicrobial peptides (AMPs) as part of their defense against microbial infections. In particular, vibrios colonize epithelia, which function as protective barriers and express AMPs as a first line of chemical defense against pathogens. Recent studies have shown they can also colonize phagocytes, key components of the animal immune system. Phagocytes infiltrate infected tissues and use AMPs to kill the phagocytosed microorganisms intracellularly, or deliver their antimicrobial content extracellularly to circumvent tissue infection. We review here the mechanisms by which vibrios have evolved the capacity to evade or resist the potent antimicrobial defenses of the immune cells or tissues they colonize. Among their strategies to resist killing by AMPs, primarily vibrios use membrane remodeling mechanisms. In particular, some highly resistant strains substitute hexaacylated Lipid A with a diglycine residue to reduce their negative surface charge, thereby lowering their electrostatic interactions with cationic AMPs. As a response to envelope stress, which can be induced by membrane-active agents including AMPs, vibrios also release outer membrane vesicles to create a protective membranous shield that traps extracellular AMPs and prevents interaction of the peptides with their own membranes. Finally, once AMPs have breached the bacterial membrane barriers, vibrios use RND efflux pumps, similar to those of other species, to transport AMPs out of their cytoplasmic space.
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Affiliation(s)
- Delphine Destoumieux-Garzón
- Ecology of Coastal Marine Systems, CNRS, Ifremer, University of Montpellier, IRD, Place Eugène Bataillon, CC80, 34095 Montpellier, France.
| | - Marylise Duperthuy
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 901 87 Umeå, Sweden.
| | - Audrey Sophie Vanhove
- Ecology of Coastal Marine Systems, CNRS, Ifremer, University of Montpellier, IRD, Place Eugène Bataillon, CC80, 34095 Montpellier, France.
| | - Paulina Schmitt
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, 2373223 Valparaíso, Chile.
| | - Sun Nyunt Wai
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 901 87 Umeå, Sweden.
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Ceccarelli D, Colwell RR. Vibrio ecology, pathogenesis, and evolution. Front Microbiol 2014; 5:256. [PMID: 24904566 PMCID: PMC4035559 DOI: 10.3389/fmicb.2014.00256] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 05/10/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Daniela Ceccarelli
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, University of Maryland College Park, MD, USA
| | - Rita R Colwell
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, University of Maryland College Park, MD, USA ; Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University Baltimore, MD, USA
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