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A Potent Inhibitor of the Cystic Fibrosis Transmembrane Conductance Regulator Blocks Disease and Morbidity Due to Toxigenic Vibrio cholerae. Toxins (Basel) 2022; 14:toxins14030225. [PMID: 35324722 PMCID: PMC8948642 DOI: 10.3390/toxins14030225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 01/24/2023] Open
Abstract
Vibrio cholerae uses cholera toxin (CT) to cause cholera, a severe diarrheal disease in humans that can lead to death within hours of the onset of symptoms. The catalytic activity of CT in target epithelial cells increases cellular levels of 3',5'-cyclic AMP (cAMP), leading to the activation of the cystic fibrosis transmembrane conductance regulator (CFTR), an apical ion channel that transports chloride out of epithelial cells, resulting in an electrolyte imbalance in the intestinal lumen and massive water loss. Here we report that when administered perorally, benzopyrimido-pyrrolo-oxazinedione, (R)-BPO-27), a potent small molecule inhibitor of CFTR, blocked disease symptoms in a mouse model for acute diarrhea caused by toxigenic V. cholerae. We show that both (R)-BPO-27 and its racemic mixture, (R/S)-BPO-27, are able to protect mice from CT-dependent diarrheal disease and death. Furthermore, we show that, consistent with the ability of the compound to block the secretory diarrhea induced by CT, BPO-27 has a measurable effect on suppressing the gut replication and survival of V. cholerae, including a 2010 isolate from Haiti that is representative of the most predominant 'variant strains' that are causing epidemic and pandemic cholera worldwide. Our results suggest that BPO-27 should advance to human Phase I studies that could further address its safety and efficacy as therapeutic or preventative drug intervention for diarrheal syndromes, including cholera, that are mediated by CFTR channel activation.
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52
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Chen J, Byun H, Liu R, Jung IJ, Pu Q, Zhu CY, Tanchoco E, Alavi S, Degnan PH, Ma AT, Roggiani M, Beld J, Goulian M, Hsiao A, Zhu J. A commensal-encoded genotoxin drives restriction of Vibrio cholerae colonization and host gut microbiome remodeling. Proc Natl Acad Sci U S A 2022; 119:e2121180119. [PMID: 35254905 PMCID: PMC8931321 DOI: 10.1073/pnas.2121180119] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 02/01/2022] [Indexed: 02/08/2023] Open
Abstract
SignificanceIn a polymicrobial battlefield where different species compete for nutrients and colonization niches, antimicrobial compounds are the sword and shield of commensal microbes in competition with invading pathogens and each other. The identification of an Escherichia coli-produced genotoxin, colibactin, and its specific targeted killing of enteric pathogens and commensals, including Vibrio cholerae and Bacteroides fragilis, sheds light on our understanding of intermicrobial interactions in the mammalian gut. Our findings elucidate the mechanisms through which genotoxins shape microbial communities and provide a platform for probing the larger role of enteric multibacterial interactions regarding infection and disease outcomes.
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Affiliation(s)
- Jiandong Chen
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Hyuntae Byun
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Rui Liu
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521
| | - I-Ji Jung
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Qinqin Pu
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | | | - Ethan Tanchoco
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521
| | - Salma Alavi
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521
| | - Patrick H. Degnan
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521
| | - Amy T. Ma
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19102
| | - Manuela Roggiani
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Joris Beld
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19102
| | - Mark Goulian
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Ansel Hsiao
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA 92521
| | - Jun Zhu
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
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53
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Olson ZH, Torlone C, Russell CM, Wood CA, Welch JF, Burkholder KM. Foraging risk in scavenging ecology: a study of scavenger behavior and patterns of bacterial growth. Basic Appl Ecol 2022. [DOI: 10.1016/j.baae.2022.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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54
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T6SS secretes an LPS-binding effector to recruit OMVs for exploitative competition and horizontal gene transfer. THE ISME JOURNAL 2022; 16:500-510. [PMID: 34433898 PMCID: PMC8776902 DOI: 10.1038/s41396-021-01093-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 02/07/2023]
Abstract
Outer membrane vesicles (OMVs) can function as nanoscale vectors that mediate bacterial interactions in microbial communities. How bacteria recognize and recruit OMVs inter-specifically remains largely unknown, thus limiting our understanding of the complex physiological and ecological roles of OMVs. Here, we report a ligand-receptor interaction-based OMV recruitment mechanism, consisting of a type VI secretion system (T6SS)-secreted lipopolysaccharide (LPS)-binding effector TeoL and the outer membrane receptors CubA and CstR. We demonstrated that Cupriavidus necator T6SS1 secretes TeoL to preferentially associate with OMVs in the extracellular milieu through interactions with LPS, one of the most abundant components of OMVs. TeoL associated with OMVs can further bind outer membrane receptors CubA and CstR, which tethers OMVs to the recipient cells and allows cargo to be delivered. The LPS-mediated mechanism enables bacterial cells to recruit OMVs derived from different species, and confers advantages to bacterial cells in iron acquisition, interbacterial competition, and horizontal gene transfer (HGT). Moreover, our findings provide multiple new perspectives on T6SS functionality in the context of bacterial competition and HGT, through the recruitment of OMVs.
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55
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Sit B, Fakoya B, Waldor MK. Animal models for dissecting Vibrio cholerae intestinal pathogenesis and immunity. Curr Opin Microbiol 2022; 65:1-7. [PMID: 34695646 PMCID: PMC8792189 DOI: 10.1016/j.mib.2021.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/14/2021] [Accepted: 09/20/2021] [Indexed: 02/03/2023]
Abstract
The human diarrheal disease cholera is caused by the bacterium Vibrio cholerae. Efforts to develop animal models that closely mimic cholera to study the pathogenesis of this disease began >125 years ago. Here, we review currently used non-surgical, oral inoculation-based animal models for investigation of V. cholerae intestinal colonization and disease and highlight recent discoveries that have illuminated mechanisms of cholera pathogenesis and immunity, particularly in the area of how V. cholerae interacts with the gut microbiome to influence infection. The emergence of high-throughput tools for studies of pathogen-host interactions, along with continued advances in host genetic engineering and manipulation in animal models of V. cholerae will deepen understanding of cholera pathogenesis, uncovering knowledge important for control of this globally important bacterial pathogen.
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Affiliation(s)
- Brandon Sit
- Division of Infectious Diseases, Brigham and Women’s Hospital, Boston, Massachusetts, USA,Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Bolutife Fakoya
- Division of Infectious Diseases, Brigham and Women’s Hospital, Boston, Massachusetts, USA,Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew K. Waldor
- Division of Infectious Diseases, Brigham and Women’s Hospital, Boston, Massachusetts, USA,Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA,Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Massachusetts, USA,Howard Hughes Medical Institute, Bethesda, Maryland, USA,corresponding author: , Phone: 6175254646, Address: MCP-759, 181 Longwood Avenue, Boston, Massachusetts, USA 02115
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56
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Gallegos-Monterrosa R, Coulthurst SJ. The ecological impact of a bacterial weapon: microbial interactions and the Type VI secretion system. FEMS Microbiol Rev 2021; 45:fuab033. [PMID: 34156081 PMCID: PMC8632748 DOI: 10.1093/femsre/fuab033] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 06/20/2021] [Indexed: 12/13/2022] Open
Abstract
Bacteria inhabit all known ecological niches and establish interactions with organisms from all kingdoms of life. These interactions are mediated by a wide variety of mechanisms and very often involve the secretion of diverse molecules from the bacterial cells. The Type VI secretion system (T6SS) is a bacterial protein secretion system that uses a bacteriophage-like machinery to secrete a diverse array of effectors, usually translocating them directly into neighbouring cells. These effectors display toxic activity in the recipient cell, making the T6SS an effective weapon during inter-bacterial competition and interactions with eukaryotic cells. Over the last two decades, microbiology research has experienced a shift towards using systems-based approaches to study the interactions between diverse organisms and their communities in an ecological context. Here, we focus on this aspect of the T6SS. We consider how our perspective of the T6SS has developed and examine what is currently known about the impact that bacteria deploying the T6SS can have in diverse environments, including niches associated with plants, insects and mammals. We consider how T6SS-mediated interactions can affect host organisms by shaping their microbiota, as well as the diverse interactions that can be established between different microorganisms through the deployment of this versatile secretion system.
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Affiliation(s)
| | - Sarah J Coulthurst
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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57
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The Emerging Scenario of the Gut-Brain Axis: The Therapeutic Actions of the New Actor Kefir against Neurodegenerative Diseases. Antioxidants (Basel) 2021; 10:antiox10111845. [PMID: 34829716 PMCID: PMC8614795 DOI: 10.3390/antiox10111845] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/14/2021] [Accepted: 11/17/2021] [Indexed: 12/18/2022] Open
Abstract
The fact that millions of people worldwide suffer from Alzheimer’s disease (AD) or Parkinson’s disease (PD), the two most prevalent neurodegenerative diseases (NDs), has been a permanent challenge to science. New tools were developed over the past two decades and were immediately incorporated into routines in many laboratories, but the most valuable scientific contribution was the “waking up” of the gut microbiota. Disturbances in the gut microbiota, such as an imbalance in the beneficial/pathogenic effects and a decrease in diversity, can result in the passage of undesired chemicals and cells to the systemic circulation. Recently, the potential effect of probiotics on restoring/preserving the microbiota was also evaluated regarding important metabolite and vitamin production, pathogen exclusion, immune system maturation, and intestinal mucosal barrier integrity. Therefore, the focus of the present review is to discuss the available data and conclude what has been accomplished over the past two decades. This perspective fosters program development of the next steps that are necessary to obtain confirmation through clinical trials on the magnitude of the effects of kefir in large samples.
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58
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Lin J, Xu L, Yang J, Wang Z, Shen X. Beyond dueling: roles of the type VI secretion system in microbiome modulation, pathogenesis and stress resistance. STRESS BIOLOGY 2021; 1:11. [PMID: 37676535 PMCID: PMC10441901 DOI: 10.1007/s44154-021-00008-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 08/09/2021] [Indexed: 09/08/2023]
Abstract
Bacteria inhabit diverse and dynamic environments, where nutrients may be limited and toxic chemicals can be prevalent. To adapt to these stressful conditions, bacteria have evolved specialized protein secretion systems, such as the type VI secretion system (T6SS) to facilitate their survival. As a molecular syringe, the T6SS expels various effectors into neighboring bacterial cells, eukaryotic cells, or the extracellular environment. These effectors improve the competitive fitness and environmental adaption of bacterial cells. Although primarily recognized as antibacterial weapons, recent studies have demonstrated that T6SSs have functions beyond interspecies competition. Here, we summarize recent research on the role of T6SSs in microbiome modulation, pathogenesis, and stress resistance.
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Affiliation(s)
- Jinshui Lin
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, People's Republic of China
| | - Lei Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Jianshe Yang
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, People's Republic of China
| | - Zhuo Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
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59
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Heilbronner S, Krismer B, Brötz-Oesterhelt H, Peschel A. The microbiome-shaping roles of bacteriocins. Nat Rev Microbiol 2021; 19:726-739. [PMID: 34075213 DOI: 10.1038/s41579-021-00569-w] [Citation(s) in RCA: 147] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2021] [Indexed: 02/05/2023]
Abstract
The microbiomes on human body surfaces affect health in multiple ways. They include not only commensal or mutualistic bacteria but also potentially pathogenic bacteria, which can enter sterile tissues to cause invasive infection. Many commensal bacteria produce small antibacterial molecules termed bacteriocins that have the capacity to eliminate specific colonizing pathogens; as such, bacteriocins have attracted increased attention as potential microbiome-editing tools. Metagenome-based and activity-based screening approaches have strongly expanded our knowledge of the abundance and diversity of bacteriocin biosynthetic gene clusters and the properties of a continuously growing list of bacteriocin classes. The dynamic acquisition, diversification or loss of bacteriocin genes can shape the fitness of a bacterial strain that is in competition with bacteriocin-susceptible bacteria. However, a bacteriocin can only provide a competitive advantage if its fitness benefit exceeds the metabolic cost of production, if it spares crucial mutualistic partner strains and if major competitors cannot develop resistance. In contrast to most currently available antibiotics, many bacteriocins have only narrow activity ranges and could be attractive agents for precision therapy and prevention of infections. A common scientific strategy involving multiple disciplines is needed to uncover the immense potential of microbiome-shaping bacteriocins.
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Affiliation(s)
- Simon Heilbronner
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Infection Biology, University of Tübingen, Tübingen, Germany. .,Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany.
| | - Bernhard Krismer
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Infection Biology, University of Tübingen, Tübingen, Germany.,Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
| | - Heike Brötz-Oesterhelt
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany.,Interfaculty Institute of Microbiology and Infection Medicine, Department of Microbial Bioactive Compounds, University of Tübingen, Tübingen, Germany
| | - Andreas Peschel
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Infection Biology, University of Tübingen, Tübingen, Germany. .,Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany.
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60
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Abstract
The gut microbiota plays a crucial role in susceptibility to enteric pathogens, including Citrobacter rodentium, a model extracellular mouse pathogen that colonizes the colonic mucosa. C. rodentium infection outcomes vary between mouse strains, with C57BL/6 and C3H/HeN mice clearing and succumbing to the infection, respectively. Kanamycin (Kan) treatment at the peak of C57BL/6 mouse infection with Kan-resistant C. rodentium resulted in relocalization of the pathogen from the colonic mucosa and cecum to solely the cecal luminal contents; cessation of the Kan treatment resulted in rapid clearance of the pathogen. We now show that in C3H/HeN mice, following Kan-induced displacement of C. rodentium to the cecum, the pathogen stably colonizes the cecal lumens of 65% of the mice in the absence of continued antibiotic treatment, a phenomenon that we term antibiotic-induced bacterial commensalization (AIBC). AIBC C. rodentium was well tolerated by the host, which showed few signs of inflammation; passaged AIBC C. rodentium robustly infected naive C3H/HeN mice, suggesting that the AIBC state is transient and did not select for genetically avirulent C. rodentium mutants. Following withdrawal of antibiotic treatment, 35% of C3H/HeN mice were able to prevent C. rodentium commensalization in the gut lumen. These mice presented a bloom of a commensal species, Citrobacter amalonaticus, which inhibited the growth of C. rodentiumin vitro in a contact-dependent manner and the luminal growth of AIBC C. rodentiumin vivo. Overall, our data suggest that commensal species can confer colonization resistance to closely related pathogenic species.
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61
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T6SS translocates a micropeptide to suppress STING-mediated innate immunity by sequestering manganese. Proc Natl Acad Sci U S A 2021; 118:2103526118. [PMID: 34625471 DOI: 10.1073/pnas.2103526118] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2021] [Indexed: 12/14/2022] Open
Abstract
Cellular ionic concentrations are a central factor orchestrating host innate immunity, but no pathogenic mechanism that perturbs host innate immunity by directly targeting metal ions has yet been described. Here, we report a unique virulence strategy of Yersinia pseudotuberculosis (Yptb) involving modulation of the availability of Mn2+, an immunostimulatory metal ion in host cells. We showed that the Yptb type VI secretion system (T6SS) delivered a micropeptide, TssS, into host cells to enhance its virulence. The mutant strain lacking TssS (ΔtssS) showed substantially reduced virulence but induced a significantly stronger host innate immune response, indicating an antagonistic role of this effector in host antimicrobial immunity. Subsequent studies revealed that TssS is a Mn2+-chelating protein and that its Mn2+-chelating ability is essential for the disruption of host innate immunity. Moreover, we showed that Mn2+ enhances the host innate immune response to Yptb infection by activating the stimulator of interferon genes (STING)-mediated immune response. Furthermore, we demonstrated that TssS counteracted the cytoplasmic Mn2+ increase to inhibit the STING-mediated innate immune response by sequestering Mn2+ Finally, TssS-mediated STING inhibition sabotaged bacterial clearance in vivo. These results reveal a previously unrecognized bacterial immune evasion strategy involving modulation of the bioavailability of intracellular metal ions and provide a perspective on the role of the T6SS in pathogenesis.
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62
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Human commensal gut Proteobacteria withstand type VI secretion attacks through immunity protein-independent mechanisms. Nat Commun 2021; 12:5751. [PMID: 34599171 PMCID: PMC8486750 DOI: 10.1038/s41467-021-26041-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 09/13/2021] [Indexed: 12/26/2022] Open
Abstract
While the major virulence factors for Vibrio cholerae, the cause of the devastating diarrheal disease cholera, have been extensively studied, the initial intestinal colonization of the bacterium is not well understood because non-human adult animals are refractory to its colonization. Recent studies suggest the involvement of an interbacterial killing device known as the type VI secretion system (T6SS). Here, we tested the T6SS-dependent interaction of V. cholerae with a selection of human gut commensal isolates. We show that the pathogen efficiently depleted representative genera of the Proteobacteria in vitro, while members of the Enterobacter cloacae complex and several Klebsiella species remained unaffected. We demonstrate that this resistance against T6SS assaults was mediated by the production of superior T6SS machinery or a barrier exerted by group I capsules. Collectively, our data provide new insights into immunity protein-independent T6SS resistance employed by the human microbiota and colonization resistance in general.
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63
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Defending against the Type Six Secretion System: beyond Immunity Genes. Cell Rep 2021; 33:108259. [PMID: 33053336 DOI: 10.1016/j.celrep.2020.108259] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/10/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
The bacterial type six secretion system (T6SS) delivers toxic effector proteins into neighboring cells, but bacteria must protect themselves against their own T6SS. Immunity genes are the best-characterized defenses, protecting against specific cognate effectors. However, the prevalence of the T6SS and the coexistence of species with heterologous T6SSs suggest evolutionary pressure selecting for additional defenses against it. Here we review defenses against the T6SS beyond self-associated immunity genes, such as diverse stress responses that can recognize T6SS-inflicted damage and coordinate induction of molecular armor, repair pathways, and overall survival. Some of these stress responses are required for full survival even in the presence of immunity genes. Finally, we propose that immunity gene-independent protection is, mechanistically, bacterial innate immunity and that such defenses and the T6SS have co-evolved and continue to shape one another in polymicrobial communities.
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64
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Mathieu-Denoncourt A, Duperthuy M. Secretome analysis reveals a role of subinhibitory concentrations of polymyxin B in the survival of Vibrio cholerae mediated by the type VI secretion system. Environ Microbiol 2021; 24:1133-1149. [PMID: 34490971 DOI: 10.1111/1462-2920.15762] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 09/04/2021] [Indexed: 11/30/2022]
Abstract
Antimicrobials are commonly used in prevention of infections including in aquaculture, agriculture and medicine. Subinhibitory concentrations of antimicrobial peptides can modulate resistance, virulence and persistence effectors in Gram-negative pathogens. In this study, we investigated the effect of subinhibitory concentrations of polymyxin B (PmB) on the secretome of Vibrio cholerae, a natural inhabitant of aquatic environments and the pathogen responsible for the cholera disease. Our proteomic approach revealed that the abundance of many extracellular proteins is affected by PmB and some of them are detected only either in the presence or in the absence of PmB. The type VI secretion system (T6SS) secreted hemolysin-coregulated protein (Hcp) displayed an increased abundance in the presence of PmB. Hcp is also more abundant in the bacterial cells in the presence of PmB and hcp expression is upregulated upon PmB supplementation. No effect of the T6SS on antimicrobial resistance was observed. Conversely, PmB increases the T6SS-dependent cytotoxicity of V. cholerae towards the amoeba Dictyostelium discoideum and its ability to compete with Escherichia coli.
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Affiliation(s)
- Annabelle Mathieu-Denoncourt
- Department de Microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montreal, Montreal, Quebec, H3T 1J4, Canada
| | - Marylise Duperthuy
- Department de Microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montreal, Montreal, Quebec, H3T 1J4, Canada
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65
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Reed CJ, Hutinet G, de Crécy-Lagard V. Comparative Genomic Analysis of the DUF34 Protein Family Suggests Role as a Metal Ion Chaperone or Insertase. Biomolecules 2021; 11:1282. [PMID: 34572495 PMCID: PMC8469502 DOI: 10.3390/biom11091282] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022] Open
Abstract
Members of the DUF34 (domain of unknown function 34) family, also known as the NIF3 protein superfamily, are ubiquitous across superkingdoms. Proteins of this family have been widely annotated as "GTP cyclohydrolase I type 2" through electronic propagation based on one study. Here, the annotation status of this protein family was examined through a comprehensive literature review and integrative bioinformatic analyses that revealed varied pleiotropic associations and phenotypes. This analysis combined with functional complementation studies strongly challenges the current annotation and suggests that DUF34 family members may serve as metal ion insertases, chaperones, or metallocofactor maturases. This general molecular function could explain how DUF34 subgroups participate in highly diversified pathways such as cell differentiation, metal ion homeostasis, pathogen virulence, redox, and universal stress responses.
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Affiliation(s)
- Colbie J. Reed
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA; (C.J.R.); (G.H.)
| | - Geoffrey Hutinet
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA; (C.J.R.); (G.H.)
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA; (C.J.R.); (G.H.)
- Genetics Institute, University of Florida, Gainesville, FL 32611, USA
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66
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Crisan CV, Chandrashekar H, Everly C, Steinbach G, Hill SE, Yunker PJ, Lieberman RR, Hammer BK. A New Contact Killing Toxin Permeabilizes Cells and Belongs to a Broadly Distributed Protein Family. mSphere 2021; 6:e0031821. [PMID: 34287011 PMCID: PMC8386463 DOI: 10.1128/msphere.00318-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/21/2021] [Indexed: 01/12/2023] Open
Abstract
Vibrio cholerae is an aquatic Gram-negative bacterium that causes severe diarrheal cholera disease when ingested by humans. To eliminate competitor cells in both the external environment and inside hosts, V. cholerae uses the type VI secretion system (T6SS). The T6SS is a macromolecular contact-dependent weapon employed by many Gram-negative bacteria to deliver cytotoxic proteins into adjacent cells. In addition to canonical T6SS gene clusters encoded by all sequenced V. cholerae isolates, strain BGT49 encodes another locus, which we named auxiliary (Aux) cluster 4. The Aux 4 cluster is located on a mobile genetic element and can be used by killer cells to eliminate both V. cholerae and Escherichia coli cells in a T6SS-dependent manner. A putative toxin encoded in the cluster, which we name TpeV (type VI permeabilizing effector Vibrio), shares no homology to known proteins and does not contain motifs or domains indicative of function. Ectopic expression of TpeV in the periplasm of E. coli permeabilizes cells and disrupts the membrane potential. Using confocal microscopy, we confirm that susceptible target cells become permeabilized when competed with killer cells harboring the Aux 4 cluster. We also determine that tpiV, the gene located immediately downstream of tpeV, encodes an immunity protein that neutralizes the toxicity of TpeV. Finally, we show that TpeV homologs are broadly distributed across important human, animal, and plant pathogens and are localized in proximity to other T6SS genes. Our results suggest that TpeV is a toxin that belongs to a large family of T6SS proteins. IMPORTANCE Bacteria live in polymicrobial communities where competition for resources and space is essential for survival. Proteobacteria use the T6SS to eliminate neighboring cells and cause disease. However, the mechanisms by which many T6SS toxins kill or inhibit susceptible target cells are poorly understood. The sequence of the TpeV toxin that we describe here is unlike any previously described protein. We demonstrate that it has antimicrobial activity by permeabilizing cells, eliminating membrane potentials, and causing severe cytotoxicity. TpeV homologs are found near known T6SS genes in human, animal, and plant bacterial pathogens, indicating that the toxin is a representative member of a broadly distributed protein family. We propose that TpeV-like toxins contribute to the fitness of many bacteria. Finally, since antibiotic resistance is a critical global health threat, the discovery of new antimicrobial mechanisms could lead to the development of new treatments against resistant strains.
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Affiliation(s)
- Cristian V. Crisan
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Harshini Chandrashekar
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Catherine Everly
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Gabi Steinbach
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Shannon E. Hill
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Peter J. Yunker
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Raquel R. Lieberman
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Brian K. Hammer
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
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67
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The Vibrio cholerae Type Six Secretion System Is Dispensable for Colonization but Affects Pathogenesis and the Structure of Zebrafish Intestinal Microbiome. Infect Immun 2021; 89:e0015121. [PMID: 34097462 DOI: 10.1128/iai.00151-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Zebrafish (Danio rerio) are an attractive model organism for a variety of scientific studies, including host-microbe interactions. The organism is particularly useful for the study of aquatic microbes that can colonize vertebrate hosts, including Vibrio cholerae, an intestinal pathogen. V. cholerae must colonize the intestine of an exposed host for pathogenicity to occur. While numerous studies have explored various aspects of the pathogenic effects of V. cholerae on zebrafish and other model organisms, few, if any, have examined how a V. cholerae infection alters the resident intestinal microbiome and the role of the type six secretion system (T6SS) in that process. In this study, 16S rRNA gene sequencing was utilized to investigate how strains of V. cholerae both with and without the T6SS alter the aforementioned microbial profiles following an infection. V. cholerae infection induced significant changes in the zebrafish intestinal microbiome, and while not necessary for colonization, the T6SS was important for inducing mucin secretion, a marker for diarrhea. Additional salient differences to the microbiome were observed based on the presence or absence of the T6SS in the V. cholerae utilized for challenging the zebrafish hosts. We conclude that V. cholerae significantly modulates the zebrafish intestinal microbiome to enable colonization and that the T6SS is important for pathogenesis induced by the examined V. cholerae strains. Furthermore, the presence or absence of T6SS differentially and significantly affected the composition and structure of the intestinal microbiome, with an increased abundance of other Vibrio bacteria observed in the absence of V. cholerae T6SS.
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68
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Inhibiting Type VI Secretion System Activity with a Biomimetic Peptide Designed To Target the Baseplate Wedge Complex. mBio 2021; 12:e0134821. [PMID: 34372705 PMCID: PMC8406304 DOI: 10.1128/mbio.01348-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Human health is threatened by bacterial infections that are increasingly resistant to multiple drugs. A recently emerged strategy consists of disarming pathogenic bacteria by targeting and blocking their virulence factors. The type VI secretion system (T6SS) is a widespread secretion nanomachine encoded and employed by pathogenic strains to establish their virulence process during host invasion. Given the conservation of T6SS in several human bacterial pathogens, the discovery of an effective broad-spectrum T6SS virulence blocker represents an attractive target for development of antivirulence therapies. Here, we identified and validated a protein-protein interaction interface, TssK-TssG, as a key factor in the assembly of the T6SS baseplate (BP) complex in the pathogen enteroaggregative Escherichia coli (EAEC). In silico and biochemical studies revealed that the determinants of the interface are broadly conserved among pathogenic species, suggesting a role for this interface as a target for T6SS inhibition. Based on the high-resolution structure of the TssKFGE wedge complex, we rationally designed a biomimetic cyclic peptide (BCP) that blocks the assembly of the EAEC BP complex and inhibits the function of T6SS in bacterial cultures. Our BCP is the first compound completely designed from prior structural knowledge with anti-T6SS activity that can be used as a model to target human pathogens.
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69
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Dissecting serotype-specific contributions to live oral cholera vaccine efficacy. Proc Natl Acad Sci U S A 2021; 118:2018032118. [PMID: 33558237 DOI: 10.1073/pnas.2018032118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The O1 serogroup of Vibrio cholerae causes pandemic cholera and is divided into the Ogawa and Inaba serotypes. The O-antigen is V. cholerae's immunodominant antigen, and the two serotypes, which differ by the presence or absence of a terminally methylated O-antigen, likely influence development of immunity to cholera and oral cholera vaccines (OCVs). However, there is no consensus regarding the relative immunological potency of each serotype, in part because previous studies relied on genetically heterogeneous strains. Here, we engineered matched serotype variants of a live OCV candidate, HaitiV, and used a germfree mouse model to evaluate the immunogenicity and protective efficacy of each vaccine serotype. By combining vibriocidal antibody quantification with single- and mixed-strain infection assays, we found that all three HaitiV variants-InabaV, OgawaV, and HikoV (bivalent Inaba/Ogawa)-were immunogenic and protective. None of the vaccine serotypes were superior across both of these vaccine metrics, suggesting that the impact of O1-serotype variation in OCV design, although detectable, is subtle. However, all three live vaccines significantly outperformed formalin-killed HikoV, supporting the idea that live OCV usage will bolster current cholera control practices. The potency of OCVs was found to be challenge strain-dependent, emphasizing the importance of appropriate strain selection for cholera challenge studies. Our findings and experimental approaches will be valuable for guiding the development of live OCVs and oral vaccines for additional pathogens.
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70
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Arab S, Nalbone L, Giarratana F, Berbar A. Vibrio spp. in Wild and Farmed Mytilus galloprovincialis along the Algerian Mediterranean Coast: Evidence of V. cholerae 01 Serotype Ogawa. JOURNAL OF AQUATIC FOOD PRODUCT TECHNOLOGY 2021. [DOI: 10.1080/10498850.2021.1936326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Sonia Arab
- Institut des Sciences Vétérinaires, Laboratoire de Recherche de Biotechnologies Liées À la Reproduction Animale, University of Saad Dahlab - Blida, Blida, Algeria
| | - Luca Nalbone
- Department of Veterinary Sciences, University of Messina, Polo Universitario dell’Annunziata, Messina, Italy
| | - Filippo Giarratana
- Department of Veterinary Sciences, University of Messina, Polo Universitario dell’Annunziata, Messina, Italy
| | - Ali Berbar
- Institut des Sciences Vétérinaires, Laboratoire de Recherche de Biotechnologies Liées À la Reproduction Animale, University of Saad Dahlab - Blida, Blida, Algeria
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71
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Sensing of intracellular Hcp levels controls T6SS expression in Vibrio cholerae. Proc Natl Acad Sci U S A 2021; 118:2104813118. [PMID: 34161288 DOI: 10.1073/pnas.2104813118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The type 6 secretion system (T6SS) is a bacterial weapon broadly distributed in gram-negative bacteria and used to kill competitors and predators. Featuring a long and double-tubular structure, this molecular machine is energetically costly to produce and thus is likely subject to diverse regulation strategies that are largely ill defined. In this study, we report a quantity-sensing control of the T6SS that down-regulates the expression of secreted components when they accumulate in the cytosol due to T6SS inactivation. Using Vibrio cholerae strains that constitutively express an active T6SS, we demonstrate that mRNA levels of secreted components, including the inner-tube protein component Hcp, were down-regulated in T6SS structural gene mutants while expression of the main structural genes remained unchanged. Deletion of both hcp gene copies restored expression from their promoters, while Hcp overexpression negatively impacted expression. We show that Hcp directly interacts with the RpoN-dependent T6SS regulator VasH, and deleting the N-terminal regulator domain of VasH abolishes this interaction as well as the expression difference of hcp operons between T6SS-active and inactive strains. We find that negative regulation of hcp also occurs in other V. cholerae strains and the pathogens Aeromonas dhakensis and Pseudomonas aeruginosa This Hcp-dependent sensing control is likely an important energy-conserving mechanism that enables T6SS-encoding organisms to quickly adjust T6SS expression and prevent wasteful build-up of its major secreted components in the absence of their efficient export out of the bacterial cell.
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72
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Differential Cellular Response to Translocated Toxic Effectors and Physical Penetration by the Type VI Secretion System. Cell Rep 2021; 31:107766. [PMID: 32553162 DOI: 10.1016/j.celrep.2020.107766] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 04/28/2020] [Accepted: 05/21/2020] [Indexed: 01/06/2023] Open
Abstract
The type VI secretion system (T6SS) is a lethal microbial weapon that injects a large needle-like structure carrying toxic effectors into recipient cells through physical penetration. How recipients respond to physical force and effectors remains elusive. Here, we use a series of effector mutants of Vibrio cholerae to determine how T6SS elicits response in Pseudomonas aeruginosa and Escherichia coli. We show that TseL, but no other effectors or physical puncture, triggers the tit-for-tat response of P. aeruginosa H1-T6SS. Although E. coli is sensitive to all periplasmically expressed effectors, P. aeruginosa is most sensitive to TseL alone. We identify a number of stress response pathways that confer protection against TseL. Physical puncture of T6SS has a moderate inhibitory effect only on envelope-impaired tolB and rseA mutants. Our data reveal that recipient cells primarily respond to effector toxicity but not to physical contact, and they rely on the stress response for immunity-independent protection.
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73
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Hussain NAS, Kirchberger PC, Case RJ, Boucher YF. Modular Molecular Weaponry Plays a Key Role in Competition Within an Environmental Vibrio cholerae Population. Front Microbiol 2021; 12:671092. [PMID: 34122386 PMCID: PMC8189183 DOI: 10.3389/fmicb.2021.671092] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
The type VI secretion system (T6SS) operons of Vibrio cholerae contain extraordinarily diverse arrays of toxic effector and cognate immunity genes, which are thought to play an important role in the environmental lifestyle and adaptation of this human pathogen. Through the T6SS, proteinaceous "spears" tipped with antibacterial effectors are injected into adjacent cells, killing those not possessing immunity proteins to these effectors. Here, we investigate the T6SS-mediated dynamics of bacterial competition within a single environmental population of V. cholerae. We show that numerous members of a North American V. cholerae population possess strain-specific repertoires of cytotoxic T6SS effector and immunity genes. Using pairwise competition assays, we demonstrate that the vast majority of T6SS-mediated duels end in stalemates between strains with different T6SS repertoires. However, horizontally acquired effector and immunity genes can significantly alter the outcome of these competitions. Frequently observed horizontal gene transfer events can both increase or reduce competition between distantly related strains by homogenizing or diversifying the T6SS repertoire. Our results also suggest temperature-dependent outcomes in T6SS competition, with environmental isolates faring better against a pathogenic strain under native conditions than under those resembling a host-associated environment. Taken altogether, these interactions produce density-dependent fitness effects and a constant T6SS-mediated arms race in individual V. cholerae populations, which could ultimately preserve intraspecies diversity. Since T6SSs are widespread, we expect within-population diversity in T6SS repertoires and the resulting competitive dynamics to be a common theme in bacterial species harboring this machinery.
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Affiliation(s)
- Nora A. S. Hussain
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Paul C. Kirchberger
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States
| | - Rebecca J. Case
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yann F. Boucher
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
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74
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Goodrich-Blair H. Interactions of host-associated multispecies bacterial communities. Periodontol 2000 2021; 86:14-31. [PMID: 33690897 DOI: 10.1111/prd.12360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The oral microbiome comprises microbial communities colonizing biotic (epithelia, mucosa) and abiotic (enamel) surfaces. Different communities are associated with health (eg, immune development, pathogen resistance) and disease (eg, tooth loss and periodontal disease). Like any other host-associated microbiome, colonization and persistence of both beneficial and dysbiotic oral microbiomes are dictated by successful utilization of available nutrients and defense against host and competitor assaults. This chapter will explore these general features of microbe-host interactions through the lens of symbiotic (mutualistic and antagonistic/pathogenic) associations with nonmammalian animals. Investigations in such systems across a broad taxonomic range have revealed conserved mechanisms and processes that underlie the complex associations among microbes and between microbes and hosts.
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Affiliation(s)
- Heidi Goodrich-Blair
- Department of Microbiology, University of Tennessee-Knoxville, Knoxville, Tennessee, USA
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75
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Crisan CV, Nichols HL, Wiesenfeld S, Steinbach G, Yunker PJ, Hammer BK. Glucose confers protection to Escherichia coli against contact killing by Vibrio cholerae. Sci Rep 2021; 11:2935. [PMID: 33536444 PMCID: PMC7858629 DOI: 10.1038/s41598-021-81813-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/18/2020] [Indexed: 01/30/2023] Open
Abstract
Evolutionary arms races are broadly prevalent among organisms including bacteria, which have evolved defensive strategies against various attackers. A common microbial aggression mechanism is the type VI secretion system (T6SS), a contact-dependent bacterial weapon used to deliver toxic effector proteins into adjacent target cells. Sibling cells constitutively express immunity proteins that neutralize effectors. However, less is known about factors that protect non-sibling bacteria from T6SS attacks independently of cognate immunity proteins. In this study, we observe that human Escherichia coli commensal strains sensitive to T6SS attacks from Vibrio cholerae are protected when co-cultured with glucose. We confirm that glucose does not impair V. cholerae T6SS activity. Instead, we find that cells lacking the cAMP receptor protein (CRP), which regulates expression of hundreds of genes in response to glucose, survive significantly better against V. cholerae T6SS attacks even in the absence of glucose. Finally, we show that the glucose-mediated T6SS protection varies with different targets and killers. Our findings highlight the first example of an extracellular small molecule modulating a genetically controlled response for protection against T6SS attacks. This discovery may have major implications for microbial interactions during pathogen-host colonization and survival of bacteria in environmental communities.
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Affiliation(s)
- Cristian V Crisan
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Holly L Nichols
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Sophia Wiesenfeld
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Gabi Steinbach
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
| | - Peter J Yunker
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
| | - Brian K Hammer
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA.
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA.
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76
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Song L, Pan J, Yang Y, Zhang Z, Cui R, Jia S, Wang Z, Yang C, Xu L, Dong TG, Wang Y, Shen X. Contact-independent killing mediated by a T6SS effector with intrinsic cell-entry properties. Nat Commun 2021; 12:423. [PMID: 33462232 PMCID: PMC7813860 DOI: 10.1038/s41467-020-20726-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/10/2020] [Indexed: 02/08/2023] Open
Abstract
Bacterial type VI secretion systems (T6SSs) inject toxic effectors into adjacent eukaryotic and prokaryotic cells. It is generally thought that this process requires physical contact between the two cells. Here, we provide evidence of contact-independent killing by a T6SS-secreted effector. We show that the pathogen Yersinia pseudotuberculosis uses a T6SS (T6SS-3) to secrete a nuclease effector that kills other bacteria in vitro and facilitates gut colonization in mice. The effector (Tce1) is a small protein that acts as a Ca2+- and Mg2+-dependent DNase, and its toxicity is inhibited by a cognate immunity protein, Tci1. As expected, T6SS-3 mediates canonical, contact-dependent killing by directly injecting Tce1 into adjacent cells. In addition, T6SS-3 also mediates killing of neighboring cells in the absence of cell-to-cell contact, by secreting Tce1 into the extracellular milieu. Efficient contact-independent entry of Tce1 into target cells requires proteins OmpF and BtuB in the outer membrane of target cells. The discovery of a contact-independent, long-range T6SS toxin delivery provides a new perspective for understanding the physiological roles of T6SS in competition. However, the mechanisms mediating contact-independent uptake of Tce1 by target cells remain unclear. Bacteria can use type VI secretion systems (T6SSs) to inject toxic effector proteins into adjacent cells, in a contact-dependent manner. Here, the authors provide evidence of contact-independent killing by a T6SS effector that is secreted into the extracellular milieu and then taken up by other bacterial cells.
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Affiliation(s)
- Li Song
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
| | - Junfeng Pan
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
| | - Yantao Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
| | - Zhenxing Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
| | - Rui Cui
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
| | - Shuangkai Jia
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
| | - Zhuo Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
| | - Changxing Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
| | - Lei Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
| | - Tao G Dong
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240, Shanghai, China.,Department of Ecosystem and Public Health, University of Calgary, Calgary, AB, T2N 4Z6, Canada
| | - Yao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China.
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China.
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77
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Cho JY, Liu R, Macbeth JC, Hsiao A. The Interface of Vibrio cholerae and the Gut Microbiome. Gut Microbes 2021; 13:1937015. [PMID: 34180341 PMCID: PMC8244777 DOI: 10.1080/19490976.2021.1937015] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/18/2021] [Accepted: 05/24/2021] [Indexed: 02/04/2023] Open
Abstract
The bacterium Vibrio cholerae is the etiologic agent of the severe human diarrheal disease cholera. The gut microbiome, or the native community of microorganisms found in the human gastrointestinal tract, is increasingly being recognized as a factor in driving susceptibility to infection, in vivo fitness, and host interactions of this pathogen. Here, we review a subset of the emerging studies in how gut microbiome structure and microbial function are able to drive V. cholerae virulence gene regulation, metabolism, and modulate host immune responses to cholera infection and vaccination. Improved mechanistic understanding of commensal-pathogen interactions offers new perspectives in the design of prophylactic and therapeutic approaches for cholera control.
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Affiliation(s)
- Jennifer Y. Cho
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
- Department of Biochemistry, University of California, Riverside, California, USA
| | - Rui Liu
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
- Graduate Program in Genetics, Genomics, and Bioinformatics, University of California, Riverside, California, USA
| | - John C. Macbeth
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California, USA
| | - Ansel Hsiao
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
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78
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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: 12] [Impact Index Per Article: 3.0] [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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79
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Hsiao A, Zhu J. Pathogenicity and virulence regulation of Vibrio cholerae at the interface of host-gut microbiome interactions. Virulence 2020; 11:1582-1599. [PMID: 33172314 PMCID: PMC7671094 DOI: 10.1080/21505594.2020.1845039] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022] Open
Abstract
The Gram-negative bacterium Vibrio cholerae is responsible for the severe diarrheal pandemic disease cholera, representing a major global public health concern. This pathogen transitions from aquatic reservoirs into epidemics in human populations, and has evolved numerous mechanisms to sense this transition in order to appropriately regulate its gene expression for infection. At the intersection of pathogen and host in the gastrointestinal tract lies the community of native gut microbes, the gut microbiome. It is increasingly clear that the diversity of species and biochemical activities within the gut microbiome represents a driver of infection outcome, through their ability to manipulate the signals used by V. cholerae to regulate virulence and fitness in vivo. A better mechanistic understanding of how commensal microbial action interacts with V. cholerae pathogenesis may lead to novel prophylactic and therapeutic interventions for cholera. Here, we review a subset of this burgeoning field of research.
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Affiliation(s)
- Ansel Hsiao
- Department of Microbiology & Plant Pathology, University of California Riverside, Riverside, CA, USA
| | - Jun Zhu
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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80
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Abstract
Pathogenic Vibrio cholerae strains express multiple virulence factors that are encoded by bacteriophage and chromosomal islands. These include cholera toxin and the intestinal colonization pilus called the toxin-coregulated pilus, which are essential for causing severe disease in humans. However, it is presently unclear how the expression of these horizontally acquired accessory virulence genes can be efficiently integrated with preexisting transcriptional programs that are presumably fine-tuned for optimal expression in V. cholerae before its conversion to a human pathogen. Here, we report the role of a transcriptional regulator (TsrA) in silencing horizontally acquired genes encoding important virulence factors. We propose that this factor could be critical to the efficient acquisition of accessory virulence genes by silencing their expression until other signals trigger their transcriptional activation within the host. Vibrio cholerae is a globally important pathogen responsible for the severe epidemic diarrheal disease called cholera. The current and ongoing seventh pandemic of cholera is caused by El Tor strains, which have completely replaced the sixth-pandemic classical strains of V. cholerae. To successfully establish infection and disseminate to new victims, V. cholerae relies on key virulence factors encoded on horizontally acquired genetic elements. The expression of these factors relies on the regulatory architecture that coordinates the timely expression of virulence determinants during host infection. Here, we apply transcriptomics and structural modeling to understand how type VI secretion system regulator A (TsrA) affects gene expression in both the classical and El Tor biotypes of V. cholerae. We find that TsrA acts as a negative regulator of V. cholerae virulence genes encoded on horizontally acquired genetic elements. The TsrA regulon comprises genes encoding cholera toxin (CT), the toxin-coregulated pilus (TCP), and the type VI secretion system (T6SS), as well as genes involved in biofilm formation. The majority of the TsrA regulon is carried on horizontally acquired AT-rich genetic islands whose loss or acquisition could be directly ascribed to the differences between the classical and El Tor strains studied. Our modeling predicts that the TsrA protein is a structural homolog of the histone-like nucleoid structuring protein (H-NS) oligomerization domain and is likely capable of forming higher-order superhelical structures, potentially with DNA. These findings describe how TsrA can integrate into the intricate V. cholerae virulence gene expression program, controlling gene expression through transcriptional silencing.
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81
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Snelders NC, Rovenich H, Petti GC, Rocafort M, van den Berg GCM, Vorholt JA, Mesters JR, Seidl MF, Nijland R, Thomma BPHJ. Microbiome manipulation by a soil-borne fungal plant pathogen using effector proteins. NATURE PLANTS 2020; 6:1365-1374. [PMID: 33139860 DOI: 10.1038/s41477-020-00799-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 09/29/2020] [Indexed: 05/23/2023]
Abstract
During colonization of their hosts, pathogens secrete effector proteins to promote disease development through various mechanisms. Increasing evidence shows that the host microbiome plays a crucial role in health, and that hosts actively shape their microbiomes to suppress disease. We proposed that pathogens evolved to manipulate host microbiomes to their advantage in turn. Here, we show that the previously identified virulence effector VdAve1, secreted by the fungal plant pathogen Verticillium dahliae, displays antimicrobial activity and facilitates colonization of tomato and cotton through the manipulation of their microbiomes by suppressing antagonistic bacteria. Moreover, we show that VdAve1, and also the newly identified antimicrobial effector VdAMP2, are exploited for microbiome manipulation in the soil environment, where the fungus resides in absence of a host. In conclusion, we demonstrate that a fungal plant pathogen uses effector proteins to modulate microbiome compositions inside and outside the host, and propose that pathogen effector catalogues represent an untapped resource for new antibiotics.
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Affiliation(s)
- Nick C Snelders
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | - Hanna Rovenich
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | - Gabriella C Petti
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Mercedes Rocafort
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Grardy C M van den Berg
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | | | - Jeroen R Mesters
- Institute of Biochemistry, University of Lübeck, Center for Structural and Cell Biology in Medicine, Lübeck, Germany
| | - Michael F Seidl
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, Utrecht, the Netherlands
| | - Reindert Nijland
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- Marine Animal Ecology Group, Wageningen University and Research, Wageningen, the Netherlands
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands.
- Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Botanical Institute, Cologne, Germany.
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82
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Smith WPJ, Brodmann M, Unterweger D, Davit Y, Comstock LE, Basler M, Foster KR. The evolution of tit-for-tat in bacteria via the type VI secretion system. Nat Commun 2020; 11:5395. [PMID: 33106492 PMCID: PMC7589516 DOI: 10.1038/s41467-020-19017-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 09/22/2020] [Indexed: 02/06/2023] Open
Abstract
Tit-for-tat is a familiar principle from animal behavior: individuals respond in kind to being helped or harmed by others. Remarkably some bacteria appear to display tit-for-tat behavior, but how this evolved is not understood. Here we combine evolutionary game theory with agent-based modelling of bacterial tit-for-tat, whereby cells stab rivals with poisoned needles (the type VI secretion system) after being stabbed themselves. Our modelling shows tit-for-tat retaliation is a surprisingly poor evolutionary strategy, because tit-for-tat cells lack the first-strike advantage of preemptive attackers. However, if cells retaliate strongly and fire back multiple times, we find that reciprocation is highly effective. We test our predictions by competing Pseudomonas aeruginosa (a tit-for-tat species) with Vibrio cholerae (random-firing), revealing that P. aeruginosa does indeed fire multiple times per incoming attack. Our work suggests bacterial competition has led to a particular form of reciprocation, where the principle is that of strong retaliation, or 'tits-for-tat'.
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Affiliation(s)
- William P J Smith
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, UK.
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
| | - Maj Brodmann
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056, Basel, Switzerland
| | - Daniel Unterweger
- Institute for Experimental Medicine, Kiel University, 24105, Kiel, Germany
- Max-Planck Institute for Evolutionary Biology, 24306, Plön, Germany
| | - Yohan Davit
- Institut de Mécanique des Fluides de Toulouse, CNRS and Université de Toulouse, 31400, Toulouse, France
| | - Laurie E Comstock
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - Marek Basler
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056, Basel, Switzerland
| | - Kevin R Foster
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, UK.
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
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83
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Qin Z, Yang X, Chen G, Park C, Liu Z. Crosstalks Between Gut Microbiota and Vibrio Cholerae. Front Cell Infect Microbiol 2020; 10:582554. [PMID: 33194819 PMCID: PMC7644805 DOI: 10.3389/fcimb.2020.582554] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 09/17/2020] [Indexed: 12/11/2022] Open
Abstract
Vibrio cholerae, the causative agent of cholera, could proliferate in aquatic environment and infect humans through contaminated food and water. Enormous microorganisms residing in human gastrointestinal tract establish a special microecological system, which immediately responds to the invasion of V. cholerae, through “colonization resistance” mechanisms, such as antimicrobial peptide production, nutrients competition, and intestinal barrier maintenances. Meanwhile, V. cholerae could quickly sense those signals and modulate the expression of relevant genes to circumvent those stresses during infection, leading to successful colonization on the surface of small intestinal epithelial cells. In this review, we summarized the crosstalks profiles between gut microbiota and V. cholerae in the terms of Type VI Secretion System (T6SS), Quorum Sensing (QS), Reactive Oxygen Species (ROS)/pH stress, and Bioactive metabolites. These mechanisms can also be applied to molecular bacterial pathogenesis of other pathogens in host.
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Affiliation(s)
- Zixin Qin
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoman Yang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Guozhong Chen
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Chaiwoo Park
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Zhi Liu
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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84
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Hopper CP, De La Cruz LK, Lyles KV, Wareham LK, Gilbert JA, Eichenbaum Z, Magierowski M, Poole RK, Wollborn J, Wang B. Role of Carbon Monoxide in Host-Gut Microbiome Communication. Chem Rev 2020; 120:13273-13311. [PMID: 33089988 DOI: 10.1021/acs.chemrev.0c00586] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Nature is full of examples of symbiotic relationships. The critical symbiotic relation between host and mutualistic bacteria is attracting increasing attention to the degree that the gut microbiome is proposed by some as a new organ system. The microbiome exerts its systemic effect through a diverse range of metabolites, which include gaseous molecules such as H2, CO2, NH3, CH4, NO, H2S, and CO. In turn, the human host can influence the microbiome through these gaseous molecules as well in a reciprocal manner. Among these gaseous molecules, NO, H2S, and CO occupy a special place because of their widely known physiological functions in the host and their overlap and similarity in both targets and functions. The roles that NO and H2S play have been extensively examined by others. Herein, the roles of CO in host-gut microbiome communication are examined through a discussion of (1) host production and function of CO, (2) available CO donors as research tools, (3) CO production from diet and bacterial sources, (4) effect of CO on bacteria including CO sensing, and (5) gut microbiome production of CO. There is a large amount of literature suggesting the "messenger" role of CO in host-gut microbiome communication. However, much more work is needed to begin achieving a systematic understanding of this issue.
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Affiliation(s)
- Christopher P Hopper
- Institute for Experimental Biomedicine, University Hospital Wuerzburg, Wuerzburg, Bavaria DE 97080, Germany.,Department of Medicinal Chemistry, College of Pharmacy, The University of Florida, Gainesville, Florida 32611, United States
| | - Ladie Kimberly De La Cruz
- Department of Chemistry & Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303, United States
| | - Kristin V Lyles
- Department of Biology, Georgia State University, Atlanta, Georgia 30303, United States
| | - Lauren K Wareham
- The Vanderbilt Eye Institute and Department of Ophthalmology & Visual Sciences, The Vanderbilt University Medical Center and School of Medicine, Nashville, Tennessee 37232, United States
| | - Jack A Gilbert
- Department of Pediatrics, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States
| | - Zehava Eichenbaum
- Department of Biology, Georgia State University, Atlanta, Georgia 30303, United States
| | - Marcin Magierowski
- Cellular Engineering and Isotope Diagnostics Laboratory, Department of Physiology, Jagiellonian University Medical College, Cracow PL 31-531, Poland
| | - Robert K Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Sheffield S10 2TN, U.K
| | - Jakob Wollborn
- Department of Anesthesiology and Critical Care, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg DE 79085, Germany.,Department of Anesthesiology, Perioperative and Pain Management, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Binghe Wang
- Department of Chemistry & Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303, United States
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85
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Byun H, Jung IJ, Chen J, Larios Valencia J, Zhu J. Siderophore piracy enhances Vibrio cholerae environmental survival and pathogenesis. MICROBIOLOGY-SGM 2020; 166:1038-1046. [PMID: 33074088 DOI: 10.1099/mic.0.000975] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Vibrio cholerae, the aetiological agent of cholera, possesses multiple iron acquisition systems, including those for the transport of siderophores. How these systems benefit V. cholerae in low-iron, polymicrobial communities in environmental settings or during infection remains poorly understood. Here, we demonstrate that in iron-limiting conditions, co-culture of V. cholerae with a number of individual siderophore-producing microbes significantly promoted V. cholerae growth in vitro. We further show that in the host environment with low iron, V. cholerae colonizes better in adult mice in the presence of the siderophore-producing commensal Escherichia coli. Taken together, our results suggest that in aquatic reservoirs or during infection, V. cholerae may overcome environmental and host iron restriction by hijacking siderophores from other microbes.
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Affiliation(s)
- Hyuntae Byun
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - I-Ji Jung
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jiandong Chen
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jessie Larios Valencia
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jay Zhu
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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86
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Vibrio cholerae-Symbiont Interactions Inhibit Intestinal Repair in Drosophila. Cell Rep 2020; 30:1088-1100.e5. [PMID: 31995751 DOI: 10.1016/j.celrep.2019.12.094] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/28/2019] [Accepted: 12/27/2019] [Indexed: 11/20/2022] Open
Abstract
Pathogen-mediated damage to the intestinal epithelium activates compensatory growth and differentiation repair programs in progenitor cells. Accelerated progenitor growth replenishes damaged tissue and maintains barrier integrity. Despite the importance of epithelial renewal to intestinal homeostasis, we know little about the effects of pathogen-commensal interactions on progenitor growth. We find that the enteric pathogen Vibrio cholerae blocks critical growth and differentiation pathways in Drosophila progenitors, despite extensive damage to epithelial tissue. We show that the inhibition of epithelial repair requires interactions between the Vibrio cholerae type six secretion system and a community of common symbiotic bacteria, as elimination of the gut microbiome is sufficient to restore homeostatic growth in infected intestines. This work highlights the importance of pathogen-symbiont interactions for intestinal immune responses and outlines the impact of the type six secretion system on pathogenesis.
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87
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Wood TE, Aksoy E, Hachani A. From Welfare to Warfare: The Arbitration of Host-Microbiota Interplay by the Type VI Secretion System. Front Cell Infect Microbiol 2020; 10:587948. [PMID: 33194832 PMCID: PMC7604300 DOI: 10.3389/fcimb.2020.587948] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/22/2020] [Indexed: 12/17/2022] Open
Abstract
The health of mammals depends on a complex interplay with their microbial ecosystems. Compartments exposed to external environments such as the mucosal surfaces of the gastrointestinal tract accommodate the gut microbiota, composed by a wide range of bacteria. The gut microbiome confers benefits to the host, including expansion of metabolic potential and the development of an immune system that can robustly protect from external and internal insults. The cooperation between gut microbiome and host is enabled in part by the formation of partitioned niches that harbor diverse bacterial phyla. Bacterial secretion systems are commonly employed to manipulate the composition of these local environments. Here, we explore the roles of the bacterial type VI secretion system (T6SS), present in ~25% of gram-negative bacteria, including many symbionts, in the establishment and perturbation of bacterial commensalism, and symbiosis in host mucosal sites. This versatile apparatus drives bacterial competition, although in some cases can also interfere directly with host cells and facilitate nutrient acquisition. In addition, some bacterial pathogens cause disease when their T6SS leads to dysbiosis and subverts host immune responses in defined animal models. This review explores our knowledge of the T6SS in the context of the “host-microbiota-pathogen” triumvirate and examines contexts in which the importance of this secretion system may be underappreciated.
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Affiliation(s)
- Thomas E Wood
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, United States.,Department of Microbiology, Harvard Medical School, Boston, MA, United States
| | - Ezra Aksoy
- Centre for Biochemical Pharmacology, William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Abderrahman Hachani
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
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88
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Perault AI, Chandler CE, Rasko DA, Ernst RK, Wolfgang MC, Cotter PA. Host Adaptation Predisposes Pseudomonas aeruginosa to Type VI Secretion System-Mediated Predation by the Burkholderia cepacia Complex. Cell Host Microbe 2020; 28:534-547.e3. [PMID: 32755549 PMCID: PMC7554260 DOI: 10.1016/j.chom.2020.06.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/05/2020] [Accepted: 06/24/2020] [Indexed: 12/14/2022]
Abstract
Pseudomonas aeruginosa and Burkholderia cepacia complex (Bcc) species are opportunistic lung pathogens of cystic fibrosis (CF) patients. While P. aeruginosa can initiate long-term infections in younger CF patients, Bcc infections only arise in teenagers and adults. Both P. aeruginosa and Bcc use type VI secretion systems (T6SSs) to mediate interbacterial competition. Here, we show P. aeruginosa isolates from teenage and adult CF patients, but not those from young CF patients, are outcompeted by the epidemic Bcc isolate Burkholderia cenocepacia strain AU1054 in a T6SS-dependent manner. The genomes of susceptible P. aeruginosa isolates harbor T6SS-abrogating mutations, the repair of which, in some cases, rendered the isolates resistant. Moreover, seven of eight Bcc strains outcompeted P. aeruginosa strains isolated from the same patients. Our findings suggest certain mutations that arise as P. aeruginosa adapts to the CF lung abrogate T6SS activity, making P. aeruginosa and its human host susceptible to potentially fatal Bcc superinfection.
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Affiliation(s)
- Andrew I Perault
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Courtney E Chandler
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD 21201, USA
| | - David A Rasko
- Institute for Genome Sciences, University of Maryland, Baltimore, Baltimore, MD 21201, USA; Department of Microbiology and Immunology, University of Maryland, Baltimore, Baltimore, MD 21201, USA
| | - Robert K Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD 21201, USA
| | - Matthew C Wolfgang
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Marsio Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Peggy A Cotter
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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89
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Lv X, Li S, Yu Y, Xiang J, Li F. The immune function of a novel crustin with an atypical WAP domain in regulating intestinal microbiota homeostasis in Litopenaeus vannamei. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 111:103756. [PMID: 32485179 DOI: 10.1016/j.dci.2020.103756] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
Crustins are a family of antimicrobial peptides (AMP) with multiple functions, including antimicrobial activity, capability of protease inhibition, phagocytosis promotion, and wound healing in crustaceans. Till present, several members of crustins have been identified and their activities were studied. However, there are still less investigations on how they play functions in vivo. Here, we identified a novel crustin with an atypical WAP domain, LvCrustin Ⅰ-1, which is mainly distributed in tissues, including intestine, gill, epidermis and stomach of the shrimp Litopenaeus vannamei. The expression level of LvCrustin Ⅰ-1 was significantly up-regulated at 3 h, 6 h, 12 h, and 24 h after Vibrio parahaemolyticus infection. Knockdown of LvCrustin Ⅰ-1 with dsRNA resulted in a significant increase of the bacteria number in hepatopancreas of shrimp upon V. parahaemolyticus infection, showing that LvCrustin Ⅰ-1 participated in pathogen infection process. Recombinant LvCrustin Ⅰ-1 protein showed microorganism-binding activity rather than antibacterial activity against tested bacteria. Furthermore, significant difference existed between the intestinal microbiota in shrimp before and after LvCrustin Ⅰ-1 knockdown based on the result of alpha and NMDS analyses. Knockdown of LvCrustin Ⅰ-1 increased the proportion of Demequina, Nautella, Propionibacterium, Anaerospora and decreased the proportion of Bacteroidia and Vibrio. These data suggest that LvCrustin Ⅰ-1 might perform its immunological function through modulation of the intestinal microbiota homeostasis rather than direct inhibition of bacterial growth in shrimp.
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Affiliation(s)
- Xinjia Lv
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Shihao Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China.
| | - Yang Yu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Jianhai Xiang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Fuhua Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; The Innovation of Seed Design, Chinese Academy of Sciences, Wuhan, China.
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90
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Eng T, Herbert RA, Martinez U, Wang B, Chen JC, Brown JB, Deutschbauer AM, Bissell MJ, Mortimer JC, Mukhopadhyay A. Iron Supplementation Eliminates Antagonistic Interactions Between Root-Associated Bacteria. Front Microbiol 2020; 11:1742. [PMID: 32793173 PMCID: PMC7387576 DOI: 10.3389/fmicb.2020.01742] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 07/03/2020] [Indexed: 01/12/2023] Open
Abstract
The rhizosphere microbiome (rhizobiome) plays a critical role in plant health and development. However, the processes by which the constituent microbes interact to form and maintain a community are not well understood. To investigate these molecular processes, we examined pairwise interactions between 11 different microbial isolates under select nutrient-rich and nutrient-limited conditions. We observed that when grown with media supplemented with 56 mM glucose, two microbial isolates were able to inhibit the growth of six other microbes. The interaction between microbes persisted even after the antagonistic microbe was removed, upon exposure to spent media. To probe the genetic basis for these antagonistic interactions, we used a barcoded transposon library in a proxy bacterium, Pseudomonas putida, to identify genes which showed enhanced sensitivity to the antagonistic factor(s) secreted by Acinetobacter sp. 02. Iron metabolism-related gene clusters in P. putida were implicated by this systems-level analysis. The supplementation of iron prevented the antagonistic interaction in the original microbial pair, supporting the hypothesis that iron limitation drives antagonistic microbial interactions between rhizobionts. We conclude that rhizobiome community composition is influenced by competition for limiting nutrients, with implications for growth and development of the plant.
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Affiliation(s)
- Thomas Eng
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Robin A. Herbert
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Uriel Martinez
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- College of Science and Engineering, San Francisco State University, San Francisco, CA, United States
| | - Brenda Wang
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Joseph C. Chen
- College of Science and Engineering, San Francisco State University, San Francisco, CA, United States
| | - James B. Brown
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Computational Biosciences Group, Computational Research Division, Computing Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Statistics, University of California, Berkeley, Berkeley, CA, United States
- Machine Learning and AI Group, Arva Intelligence Inc., Park City, UT, United States
| | - Adam M. Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Mina J. Bissell
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Jenny C. Mortimer
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Aindrila Mukhopadhyay
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
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91
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Alavi S, Mitchell JD, Cho JY, Liu R, Macbeth JC, Hsiao A. Interpersonal Gut Microbiome Variation Drives Susceptibility and Resistance to Cholera Infection. Cell 2020; 181:1533-1546.e13. [PMID: 32631492 PMCID: PMC7394201 DOI: 10.1016/j.cell.2020.05.036] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/16/2020] [Accepted: 05/18/2020] [Indexed: 12/17/2022]
Abstract
The gut microbiome is the resident microbial community of the gastrointestinal tract. This community is highly diverse, but how microbial diversity confers resistance or susceptibility to intestinal pathogens is poorly understood. Using transplantation of human microbiomes into several animal models of infection, we show that key microbiome species shape the chemical environment of the gut through the activity of the enzyme bile salt hydrolase. The activity of this enzyme reduced colonization by the major human diarrheal pathogen Vibrio cholerae by degrading the bile salt taurocholate that activates the expression of virulence genes. The absence of these functions and species permits increased infection loads on a personal microbiome-specific basis. These findings suggest new targets for individualized preventative strategies of V. cholerae infection through modulating the structure and function of the gut microbiome.
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Affiliation(s)
- Salma Alavi
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA
| | - Jonathan D Mitchell
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA
| | - Jennifer Y Cho
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA; Department of Biochemistry, University of California, Riverside, Riverside, CA, USA
| | - Rui Liu
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA; Graduate Program in Genetics, Genomics, and Bioinformatics, University of California, Riverside, Riverside, CA, USA
| | - John C Macbeth
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA; Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, USA
| | - Ansel Hsiao
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA.
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92
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Abstract
Bacteria have evolved a wide range of mechanisms to harm and kill their competitors, including chemical, mechanical and biological weapons. Here we review the incredible diversity of bacterial weapon systems, which comprise antibiotics, toxic proteins, mechanical weapons that stab and pierce, viruses, and more. The evolution of bacterial weapons is shaped by many factors, including cell density and nutrient abundance, and how strains are arranged in space. Bacteria also employ a diverse range of combat behaviours, including pre-emptive attacks, suicidal attacks, and reciprocation (tit-for-tat). However, why bacteria carry so many weapons, and why they are so often used, remains poorly understood. By comparison with animals, we argue that the way that bacteria live - often in dense and genetically diverse communities - is likely to be key to their aggression as it encourages them to dig in and fight alongside their clonemates. The intensity of bacterial aggression is such that it can strongly affect communities, via complex coevolutionary and eco-evolutionary dynamics, which influence species over space and time. Bacterial warfare is a fascinating topic for ecology and evolution, as well as one of increasing relevance. Understanding how bacteria win wars is important for the goal of manipulating the human microbiome and other important microbial systems.
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93
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Immune-Microbiota Interplay and Colonization Resistance in Infection. Mol Cell 2020; 78:597-613. [DOI: 10.1016/j.molcel.2020.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/12/2020] [Accepted: 03/02/2020] [Indexed: 02/07/2023]
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94
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Clinical, ultrasonographic, bacteriological, cytological and histological findings during uterine involution in ewes with pregnancy toxaemia and subsequent reproductive efficiency. Anim Reprod Sci 2020; 218:106460. [PMID: 32507269 DOI: 10.1016/j.anireprosci.2020.106460] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 11/22/2022]
Abstract
Objectives were to evaluate characteristics of uterine involution in ewes with pregnancy toxaemia during gestation and to study effects on subsequent reproductive performance. Pregnancy toxaemia was induced in ewes (A) by feeding an energy-deficient diet as confirmed by detecting β-hydroxybutyrate concentrations in blood indicative of this disorder. There was also a control group (C). Animals were evaluated until the 60th day post-partum using clinical and ultrasonographic examinations. Vaginal swab samples and uterine biopsy tissue samples were collected for bacteriological and cytological examination; biopsy samples were prepared for histological examination. Ewes were subsequently placed with rams and reproductive performance was ascertained. Post-partum, during the ultrasonographic examination of the uterus, ewes of Group A had caruncle and uterine lumen diameters, as well as a uterine thickness greater than ewes of Group C. Post-partum uterine blood flow volume was greater in ewes of the A than C group. Neutrophils predominated in vaginal samples, with the neutrophil proportion being less in ewes of Group A than C. There were no differences in the uterine involution process between groups. During the subsequent reproductive season, all the ewes of Group A lambed normally and produced viable lambs. It is concluded that there were no adverse effects on subsequent reproductive performance of ewes previously affected with pregnancy toxaemia, when appropriate health management was performed.
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95
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Crisan CV, Hammer BK. The
Vibrio cholerae
type VI secretion system: toxins, regulators and consequences. Environ Microbiol 2020; 22:4112-4122. [DOI: 10.1111/1462-2920.14976] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/01/2020] [Accepted: 03/02/2020] [Indexed: 12/13/2022]
Affiliation(s)
- Cristian V. Crisan
- Center for Microbial Dynamics and Infection Georgia Institute of Technology Atlanta GA USA
- Institute for Bioengineering and Biosciences, Georgia Institute of Technology Atlanta GA USA
- School of Biological Sciences, Georgia Institute of Technology Atlanta GA USA
| | - Brian K. Hammer
- Center for Microbial Dynamics and Infection Georgia Institute of Technology Atlanta GA USA
- Institute for Bioengineering and Biosciences, Georgia Institute of Technology Atlanta GA USA
- School of Biological Sciences, Georgia Institute of Technology Atlanta GA USA
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96
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Abstract
Symbiotic bacteria use diverse strategies to compete for host colonization sites. However, little is known about the environmental cues that modulate interbacterial competition as they transition between free-living and host-associated lifestyles. We used the mutualistic relationship between Eupyrmna scolopes squid and Vibrio fischeri bacteria to investigate how intraspecific competition is regulated as symbionts move from the seawater to a host-like environment. We recently reported that V. fischeri uses a type VI secretion system (T6SS) for intraspecific competition during host colonization. Here, we investigated how environmental viscosity impacts T6SS-mediated competition by using a liquid hydrogel medium that mimics the viscous host environment. Our data demonstrate that although the T6SS is functionally inactive when cells are grown under low-viscosity liquid conditions similar to those found in seawater, exposure to a host-like high-viscosity hydrogel enhances T6SS expression and sheath formation, activates T6SS-mediated killing in as little as 30 min, and promotes the coaggregation of competing genotypes. Finally, the use of mass spectrometry-based proteomics revealed insights into how cells may prepare for T6SS competition during this habitat transition. These findings, which establish the use of a new hydrogel culture condition for studying T6SS interactions, indicate that V. fischeri rapidly responds to the physical environment to activate the competitive mechanisms used during host colonization.IMPORTANCE Bacteria often engage in interference competition to gain access to an ecological niche, such as a host. However, little is known about how the physical environment experienced by free-living or host-associated bacteria influences such competition. We used the bioluminescent squid symbiont Vibrio fischeri to study how environmental viscosity impacts bacterial competition. Our results suggest that upon transition from a planktonic environment to a host-like environment, V. fischeri cells activate their type VI secretion system, a contact-dependent interbacterial nanoweapon, to eliminate natural competitors. This work shows that competitor cells form aggregates under host-like conditions, thereby facilitating the contact required for killing, and reveals how V. fischeri regulates a key competitive mechanism in response to the physical environment.
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97
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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: 22] [Impact Index Per Article: 5.5] [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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98
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Davoodi S, Foley E. Host-Microbe-Pathogen Interactions: A Review of Vibrio cholerae Pathogenesis in Drosophila. Front Immunol 2020; 10:3128. [PMID: 32038640 PMCID: PMC6993214 DOI: 10.3389/fimmu.2019.03128] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 12/23/2019] [Indexed: 12/14/2022] Open
Abstract
Most animals maintain mutually beneficial symbiotic relationships with their intestinal microbiota. Resident microbes in the gastrointestinal tract breakdown indigestible food, provide essential nutrients, and, act as a barrier against invading microbes, such as the enteric pathogen Vibrio cholerae. Over the last decades, our knowledge of V. cholerae pathogenesis, colonization, and transmission has increased tremendously. A number of animal models have been used to study how V. cholerae interacts with host-derived resources to support gastrointestinal colonization. Here, we review studies on host-microbe interactions and how infection with V. cholerae disrupts these interactions, with a focus on contributions from the Drosophila melanogaster model. We will discuss studies that highlight the connections between symbiont, host, and V. cholerae metabolism; crosstalk between V. cholerae and host microbes; and the impact of the host immune system on the lethality of V. cholerae infection. These studies suggest that V. cholerae modulates host immune-metabolic responses in the fly and improves Vibrio fitness through competition with intestinal microbes.
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Affiliation(s)
| | - Edan Foley
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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99
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Kuehl CJ, D'Gama JD, Warr AR, Waldor MK. An Oral Inoculation Infant Rabbit Model for Shigella Infection. mBio 2020; 11:e03105-19. [PMID: 31964739 PMCID: PMC6974573 DOI: 10.1128/mbio.03105-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 12/03/2019] [Indexed: 02/07/2023] Open
Abstract
Shigella species cause diarrheal disease globally. Shigellosis is typically characterized by bloody stools and colitis with mucosal damage and is the leading bacterial cause of diarrheal death worldwide. After the pathogen is orally ingested, it invades and replicates within the colonic epithelium through mechanisms that rely on its type III secretion system (T3SS). Currently, oral infection-based small animal models to study the pathogenesis of shigellosis are lacking. Here, we found that orogastric inoculation of infant rabbits with Shigella flexneri resulted in diarrhea and colonic pathology resembling that found in human shigellosis. Fasting animals prior to S. flexneri inoculation increased the frequency of disease. The pathogen colonized the colon, where both luminal and intraepithelial foci were observed. The intraepithelial foci likely arise through S. flexneri spreading from cell to cell. Robust S. flexneri intestinal colonization, invasion of the colonic epithelium, and epithelial sloughing all required the T3SS as well as IcsA, a factor required for bacterial spreading and adhesion in vitro Expression of the proinflammatory chemokine interleukin 8 (IL-8), detected with in situ mRNA labeling, was higher in animals infected with wild-type S. flexneri versus mutant strains deficient in icsA or T3SS, suggesting that epithelial invasion promotes expression of this chemokine. Collectively, our findings suggest that oral infection of infant rabbits offers a useful experimental model for studies of the pathogenesis of shigellosis and for testing of new therapeutics.IMPORTANCEShigella species are the leading bacterial cause of diarrheal death globally. The pathogen causes bacillary dysentery, a bloody diarrheal disease characterized by damage to the colonic mucosa and is usually spread through the fecal-oral route. Small animal models of shigellosis that rely on the oral route of infection are lacking. Here, we found that orogastric inoculation of infant rabbits with S. flexneri led to a diarrheal disease and colonic pathology reminiscent of human shigellosis. Diarrhea, intestinal colonization, and pathology in this model were dependent on the S. flexneri type III secretion system and IcsA, canonical Shigella virulence factors. Thus, oral infection of infant rabbits offers a feasible model to study the pathogenesis of shigellosis and to develop and test new therapeutics.
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Affiliation(s)
- Carole J Kuehl
- Division of Infectious Diseases, Brigham & Women's Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Jonathan D D'Gama
- Division of Infectious Diseases, Brigham & Women's Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Alyson R Warr
- Division of Infectious Diseases, Brigham & Women's Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew K Waldor
- Division of Infectious Diseases, Brigham & Women's Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
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100
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Allsopp LP, Bernal P, Nolan LM, Filloux A. Causalities of war: The connection between type VI secretion system and microbiota. Cell Microbiol 2020; 22:e13153. [PMID: 31872954 PMCID: PMC7540082 DOI: 10.1111/cmi.13153] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/23/2019] [Accepted: 12/19/2019] [Indexed: 12/14/2022]
Abstract
Microbiota niches have space and/or nutrient restrictions, which has led to the coevolution of cooperation, specialisation, and competition within the population. Different animal and environmental niches contain defined resident microbiota that tend to be stable over time and offer protection against undesired intruders. Yet fluxes can occur, which alter the composition of a bacterial population. In humans, the microbiota are now considered a key contributor to maintenance of health and homeostasis, and its alteration leads to dysbiosis. The bacterial type VI secretion system (T6SS) transports proteins into the environment, directly into host cells or can function as an antibacterial weapon by killing surrounding competitors. Upon contact with neighbouring cells, the T6SS fires, delivering a payload of effector proteins. In the absence of an immunity protein, this results in growth inhibition or death of prey leading to a competitive advantage for the attacker. It is becoming apparent that the T6SS has a role in modulating and shaping the microbiota at multiple levels, which is the focus of this review. Discussed here is the T6SS, its role in competition, key examples of its effect upon the microbiota, and future avenues of research.
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Affiliation(s)
- Luke P Allsopp
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Patricia Bernal
- Department of Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura M Nolan
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Alain Filloux
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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