1
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Yu X, Yan Y, Zeng J, Liu Y, Sun X, Wang Z, Li L. T6SS nuclease effectors in Pseudomonas syringae act as potent antimicrobials in interbacterial competition. J Bacteriol 2024; 206:e0027323. [PMID: 38717111 DOI: 10.1128/jb.00273-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 04/09/2024] [Indexed: 06/21/2024] Open
Abstract
Type VI secretion system (T6SS) is a potent weapon employed by various Pseudomonas species to compete with neighboring microorganisms for limited nutrients and ecological niches. However, the involvement of T6SS effectors in interbacterial competition within the phytopathogen Pseudomonas syringae remains unknown. In this study, we examined two T6SS clusters in a wild-type P. syringae MB03 and verified the involvement of one cluster, namely, T6SS-1, in interbacterial competition. Additionally, our results showed that two T6SS DNase effectors, specifically Tde1 and Tde4, effectively outcompeted antagonistic bacteria, with Tde4 playing a prominent role. Furthermore, we found several cognate immunity proteins, including Tde1ia, Tde1ib, and Tde4i, which are located in the downstream loci of their corresponding effector protein genes and worked synergistically to protect MB03 cells from self-intoxication. Moreover, expression of either Tde1 or C-terminus of Tde4 in Escherichia coli cells induced DNA degradation and changes in cell morphology. Thus, our results provide new insights into the role of the T6SS effectors of P. syringae in the interbacterial competition in the natural environment. IMPORTANCE The phytopathogen Pseudomonas syringae employs an active type VI secretion system (T6SS) to outcompete other microorganisms in the natural environment, particularly during the epiphytic growth in the phyllosphere. By examining two T6SS clusters in P. syringae MB03, T6SS-1 is found to be effective in killing Escherichia coli cells. We highlight the excellent antibacterial effect of two T6SS DNase effectors, namely, Tde1 and Tde4. Both of them function as nuclease effectors, leading to DNA degradation and cell filamentation in prey cells, ultimately resulting in cell death. Our findings deepen our understanding of the T6SS effector repertoires used in P. syringae and will facilitate the development of effective antibacterial strategies.
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Affiliation(s)
- Xun Yu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education and Hubei Province), Hubei University of Technology, Wuhan, China
| | - Yubo Yan
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Jie Zeng
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Yongxuan Liu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xiaowen Sun
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Zhiyong Wang
- College of Biological and Food Engineering, Hubei Minzu University, Enshi, China
| | - Lin Li
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
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2
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Upton C, Healey J, Rothnie AJ, Goddard AD. Insights into membrane interactions and their therapeutic potential. Arch Biochem Biophys 2024; 755:109939. [PMID: 38387829 DOI: 10.1016/j.abb.2024.109939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/31/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
Recent research into membrane interactions has uncovered a diverse range of therapeutic opportunities through the bioengineering of human and non-human macromolecules. Although the majority of this research is focussed on fundamental developments, emerging studies are showcasing promising new technologies to combat conditions such as cancer, Alzheimer's and inflammatory and immune-based disease, utilising the alteration of bacteriophage, adenovirus, bacterial toxins, type 6 secretion systems, annexins, mitochondrial antiviral signalling proteins and bacterial nano-syringes. To advance the field further, each of these opportunities need to be better understood, and the therapeutic models need to be further optimised. Here, we summarise the knowledge and insights into several membrane interactions and detail their current and potential uses therapeutically.
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Affiliation(s)
- Calum Upton
- School of Biosciences, Health & Life Science, Aston University, Birmingham, B4 7ET, UK
| | - Joseph Healey
- Nanosyrinx, The Venture Centre, University of Warwick Science Park, Coventry, CV4 7EZ, UK
| | - Alice J Rothnie
- School of Biosciences, Health & Life Science, Aston University, Birmingham, B4 7ET, UK
| | - Alan D Goddard
- School of Biosciences, Health & Life Science, Aston University, Birmingham, B4 7ET, UK.
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3
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Dahlquist-Axe G, Standeven FJ, Speller CF, Tedder A, Meehan CJ. Inferring diet, disease and antibiotic resistance from ancient human oral microbiomes. Microb Genom 2024; 10:001251. [PMID: 38739117 PMCID: PMC11165619 DOI: 10.1099/mgen.0.001251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 04/24/2024] [Indexed: 05/14/2024] Open
Abstract
The interaction between a host and its microbiome is an area of intense study. For the human host, it is known that the various body-site-associated microbiomes impact heavily on health and disease states. For instance, the oral microbiome is a source of various pathogens and potential antibiotic resistance gene pools. The effect of historical changes to the human host and environment to the associated microbiome, however, has been less well explored. In this review, we characterize several historical and prehistoric events which are considered to have impacted the oral environment and therefore the bacterial communities residing within it. The link between evolutionary changes to the oral microbiota and the significant societal and behavioural changes occurring during the pre-Neolithic, Agricultural Revolution, Industrial Revolution and Antibiotic Era is outlined. While previous studies suggest the functional profile of these communities may have shifted over the centuries, there is currently a gap in knowledge that needs to be filled. Biomolecular archaeological evidence of innate antimicrobial resistance within the oral microbiome shows an increase in the abundance of antimicrobial resistance genes since the advent and widespread use of antibiotics in the modern era. Nevertheless, a lack of research into the prevalence and evolution of antimicrobial resistance within the oral microbiome throughout history hinders our ability to combat antimicrobial resistance in the modern era.
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Affiliation(s)
- Gwyn Dahlquist-Axe
- School of Chemistry and Biosciences, University of Bradford, Bradford, UK
| | | | - Camilla F. Speller
- Department of Anthropology, University of British Columbia, Vancouver, Canada
| | - Andrew Tedder
- School of Chemistry and Biosciences, University of Bradford, Bradford, UK
| | - Conor J. Meehan
- Department of Biosciences, Nottingham Trent University, Nottingham, UK
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4
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Dessartine MM, Kosta A, Doan T, Cascales É, Côté JP. Type 1 fimbriae-mediated collective protection against type 6 secretion system attacks. mBio 2024; 15:e0255323. [PMID: 38497656 PMCID: PMC11005336 DOI: 10.1128/mbio.02553-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/25/2024] [Indexed: 03/19/2024] Open
Abstract
Bacterial competition may rely on secretion systems such as the type 6 secretion system (T6SS), which punctures and releases toxic molecules into neighboring cells. To subsist, bacterial targets must counteract the threats posed by T6SS-positive competitors. In this study, we used a comprehensive genome-wide high-throughput screening approach to investigate the dynamics of interbacterial competition. Our primary goal was to identify deletion mutants within the well-characterized E. coli K-12 single-gene deletion library, the Keio collection, that demonstrated resistance to T6SS-mediated killing by the enteropathogenic bacterium Cronobacter malonaticus. We identified 49 potential mutants conferring resistance to T6SS and focused our interest on a deletion mutant (∆fimE) exhibiting enhanced expression of type 1 fimbriae. We demonstrated that the presence of type 1 fimbriae leads to the formation of microcolonies and thus protects against T6SS-mediated assaults. Collectively, our study demonstrated that adhesive structures such as type 1 fimbriae confer collective protective behavior against T6SS attacks.IMPORTANCEType 6 secretion systems (T6SS) are molecular weapons employed by gram-negative bacteria to eliminate neighboring microbes. T6SS plays a pivotal role as a virulence factor, enabling pathogenic gram-negative bacteria to compete with the established communities to colonize hosts and induce infections. Gaining a deeper understanding of bacterial interactions will allow the development of strategies to control the action of systems such as the T6SS that can manipulate bacterial communities. In this context, we demonstrate that bacteria targeted by T6SS attacks from the enteric pathogen Cronobacter malonaticus, which poses a significant threat to infants, can develop a collective protective mechanism centered on the production of type I fimbriae. These adhesive structures promote the aggregation of bacterial preys and the formation of microcolonies, which protect the cells from T6SS attacks.
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Affiliation(s)
- Margot Marie Dessartine
- Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Artemis Kosta
- Plateforme de microscopie, Institut de Microbiologie de la Méditerranée (IMM, FR3479), Aix-Marseille Univ, CNRS, Marseille, France
| | - Thierry Doan
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR7255), Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, CNRS, Marseille, France
| | - Éric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR7255), Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, CNRS, Marseille, France
| | - Jean-Philippe Côté
- Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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5
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Zhang C, Datta S, Ratcliff WC, Hammer BK. Constitutive expression of the Type VI Secretion System carries no measurable fitness cost in Vibrio cholerae. Ecol Evol 2024; 14:e11081. [PMID: 38435022 PMCID: PMC10905242 DOI: 10.1002/ece3.11081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 02/03/2024] [Accepted: 02/13/2024] [Indexed: 03/05/2024] Open
Abstract
The Type VI Secretion System (T6SS) is a widespread and highly effective mechanism of microbial warfare; it confers the ability to efficiently kill susceptible cells within close proximity. Due to its large physical size, complexity, and ballistic basis for intoxication, it has widely been assumed to incur significant growth costs in the absence of improved competitive outcomes. In this study, we precisely examine the fitness costs of constitutive T6SS firing in the bacterium Vibrio cholerae. We find that, contrary to expectations, constitutive expression of the T6SS has a negligible impact on growth, reducing growth fitness by 0.025 ± 0.5% (95% CI) relative to a T6SS- control. Mathematical modeling of microbial populations demonstrates that, due to clonal interference, constitutive expression of the T6SS will often be neutral, with little impact on evolutionary outcomes. Our findings underscore the importance of precisely measuring the fitness costs of microbial social behaviors and help explain the prevalence of the T6SS across Gram-negative bacteria.
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Affiliation(s)
- Christopher Zhang
- School of Biological SciencesGeorgia Institute of TechnologyAtlantaGeorgiaUSA
- Interdisciplinary Graduate Program in Quantitative BiosciencesGeorgia Institute of TechnologyAtlantaGeorgiaUSA
| | - Sayantan Datta
- School of Biological SciencesGeorgia Institute of TechnologyAtlantaGeorgiaUSA
- Interdisciplinary Graduate Program in Quantitative BiosciencesGeorgia Institute of TechnologyAtlantaGeorgiaUSA
| | - William C. Ratcliff
- School of Biological SciencesGeorgia Institute of TechnologyAtlantaGeorgiaUSA
| | - Brian K. Hammer
- School of Biological SciencesGeorgia Institute of TechnologyAtlantaGeorgiaUSA
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6
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Jiang X, Li H, Ma J, Li H, Ma X, Tang Y, Li J, Chi X, Deng Y, Zeng S, Liu Z. Role of Type VI secretion system in pathogenic remodeling of host gut microbiota during Aeromonas veronii infection. THE ISME JOURNAL 2024; 18:wrae053. [PMID: 38531781 PMCID: PMC11014884 DOI: 10.1093/ismejo/wrae053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/31/2024] [Accepted: 03/21/2024] [Indexed: 03/28/2024]
Abstract
Intestinal microbial disturbance is a direct cause of host disease. The bacterial Type VI secretion system (T6SS) often plays a crucial role in the fitness of pathogenic bacteria by delivering toxic effectors into target cells. However, its impact on the gut microbiota and host pathogenesis is poorly understood. To address this question, we characterized a new T6SS in the pathogenic Aeromonas veronii C4. First, we validated the secretion function of the core machinery of A. veronii C4 T6SS. Second, we found that the pathogenesis and colonization of A. veronii C4 is largely dependent on its T6SS. The effector secretion activity of A. veronii C4 T6SS not only provides an advantage in competition among bacteria in vitro, but also contributes to occupation of an ecological niche in the nutritionally deficient and anaerobic environment of the host intestine. Metagenomic analysis showed that the T6SS directly inhibits or eliminates symbiotic strains from the intestine, resulting in dysregulated gut microbiome homeostasis. In addition, we identified three unknown effectors, Tse1, Tse2, and Tse3, in the T6SS, which contribute to T6SS-mediated bacterial competition and pathogenesis by impairing targeted cell integrity. Our findings highlight that T6SS can remodel the host gut microbiota by intricate interplay between T6SS-mediated bacterial competition and altered host immune responses, which synergistically promote pathogenesis of A. veronii C4. Therefore, this newly characterized T6SS could represent a general interaction mechanism between the host and pathogen, and may offer a potential therapeutic target for controlling bacterial pathogens.
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Affiliation(s)
- Xiaoli Jiang
- School of Life and Health Sciences, Hainan University, Haikou 570228, China
| | - Hanzeng Li
- School of Life and Health Sciences, Hainan University, Haikou 570228, China
| | - Jiayue Ma
- School of Life and Health Sciences, Hainan University, Haikou 570228, China
| | - Hong Li
- School of Life and Health Sciences, Hainan University, Haikou 570228, China
| | - Xiang Ma
- School of Life and Health Sciences, Hainan University, Haikou 570228, China
| | - Yanqiong Tang
- School of Life and Health Sciences, Hainan University, Haikou 570228, China
| | - Juanjuan Li
- School of Life and Health Sciences, Hainan University, Haikou 570228, China
| | - Xue Chi
- School of Life and Health Sciences, Hainan University, Haikou 570228, China
| | - Yong Deng
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Sheng Zeng
- Susheng Biotech (Hainan) Co., Ltd, Haikou 570228, China
| | - Zhu Liu
- School of Life and Health Sciences, Hainan University, Haikou 570228, China
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7
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Kalindamar S, Abdelhamed H, Kordon AO, Tekedar HC, Pinchuk L, Karsi A. Characterization of Type VI secretion system in Edwardsiella ictaluri. PLoS One 2023; 18:e0296132. [PMID: 38153949 PMCID: PMC10754466 DOI: 10.1371/journal.pone.0296132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 12/06/2023] [Indexed: 12/30/2023] Open
Abstract
Edwardsiella ictaluri is a Gram-negative facultative intracellular fish pathogen causing enteric septicemia of catfish (ESC). While various secretion systems contribute to E. ictaluri virulence, the Type VI secretion system (T6SS) remains poorly understood. In this study, we constructed 13 E. ictaluri T6SS mutants using splicing by overlap extension PCR and characterized them, assessing their uptake and survival in channel catfish (Ictalurus punctatus) peritoneal macrophages, attachment and invasion in channel catfish ovary (CCO) cells, in vitro stress resistance, and virulence and efficacy in channel catfish. Among the mutants, EiΔevpA, EiΔevpH, EiΔevpM, EiΔevpN, and EiΔevpO exhibited reduced replication inside peritoneal macrophages. EiΔevpM, EiΔevpN, and EiΔevpO showed significantly decreased attachment to CCO cells, while EiΔevpN and EiΔevpO also displayed reduced invasion of CCO cells (p < 0.05). Overall, T6SS mutants demonstrated enhanced resistance to oxidative and nitrosative stress in the nutrient-rich medium compared to the minimal medium. However, EiΔevpA, EiΔevpH, EiΔevpM, EiΔevpN, and EiΔevpO were susceptible to oxidative stress in both nutrient-rich and minimal medium. In fish challenges, EiΔevpD, EiΔevpE, EiΔevpG, EiΔevpJ, and EiΔevpK exhibited attenuation and provided effective protection against E. ictaluri wild-type (EiWT) infection in catfish fingerlings. However, their attenuation and protective efficacy were lower in catfish fry. These findings shed light on the role of the T6SS in E. ictaluri pathogenesis, highlighting its significance in intracellular survival, host cell attachment and invasion, stress resistance, and virulence. The attenuated T6SS mutants hold promise as potential candidates for protective immunization strategies in catfish fingerlings.
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Affiliation(s)
- Safak Kalindamar
- Department of Molecular Biology and Genetics, Faculty of Arts and Sciences, Ordu University, Ordu, Türkiye
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Adef O. Kordon
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Hasan C. Tekedar
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Lesya Pinchuk
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Attila Karsi
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
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8
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Taillefer B, Giraud JF, Cascales E. No fitness cost entailed by type VI secretion system synthesis, assembly, contraction, or disassembly in enteroaggregative Escherichia coli. J Bacteriol 2023; 205:e0035723. [PMID: 37971272 PMCID: PMC10729742 DOI: 10.1128/jb.00357-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/19/2023] Open
Abstract
IMPORTANCE Bacteria use weapons to deliver effectors into target cells. One of these weapons, the type VI secretion system (T6SS), assembles a contractile tail acting as a spring to propel a toxin-loaded needle. Due to its size and mechanism of action, the T6SS was intuitively thought to be energetically costly. Here, using a combination of mutants and growth measurements in liquid medium, on plates, and in competition experiments, we show that the T6SS does not entail a growth cost to enteroaggregative Escherichia coli.
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Affiliation(s)
- Boris Taillefer
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR 7255), Institut de Microbiologie de la Méditerranée (IMM), Aix Marseille Univ, CNRS, Marseille, France
| | - Julien F. Giraud
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR 7255), Institut de Microbiologie de la Méditerranée (IMM), Aix Marseille Univ, CNRS, Marseille, France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR 7255), Institut de Microbiologie de la Méditerranée (IMM), Aix Marseille Univ, CNRS, Marseille, France
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9
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Beauvois SG, Flaugnatti N, Ilbert M, Boyer M, Gavello-Fernandez E, Fronzes R, Jurėnas D, Journet L. The tip protein PAAR is required for the function of the type VI secretion system. Microbiol Spectr 2023; 11:e0147823. [PMID: 37800964 PMCID: PMC10715212 DOI: 10.1128/spectrum.01478-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 08/09/2023] [Indexed: 10/07/2023] Open
Abstract
IMPORTANCE The type VI secretion system (T6SS) is a bacterial contractile injection system involved in bacterial competition by the delivery of antibacterial toxins. The T6SS consists of an envelope-spanning complex that recruits the baseplate, allowing the polymerization of a contractile tail structure. The tail is a tube wrapped by a sheath and topped by the tip of the system, the VgrG spike/PAAR complex. Effectors loaded onto the puncturing tip or into the tube are propelled in the target cells upon sheath contraction. The PAAR protein tips and sharpens the VgrG spike. However, the importance and the function of this protein remain unclear. Here, we provide evidence for association of PAAR at the tip of the VgrG spike. We also found that the PAAR protein is a T6SS critical component required for baseplate and sheath assembly.
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Affiliation(s)
- Solène G. Beauvois
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
| | - Nicolas Flaugnatti
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
| | - Marianne Ilbert
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7281, Marseille, France
| | - Marie Boyer
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
| | - Esther Gavello-Fernandez
- Institut Européen de Chimie et Biologie, University of Bordeaux, Pessac, France
- CNRS UMR 5234 Microbiologie Fondamentale et Pathogénicité, Bordeaux, France
| | - Rémi Fronzes
- Institut Européen de Chimie et Biologie, University of Bordeaux, Pessac, France
- CNRS UMR 5234 Microbiologie Fondamentale et Pathogénicité, Bordeaux, France
| | - Dukas Jurėnas
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
| | - Laure Journet
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
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10
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Anderson AJG, Morrell B, Lopez Campos G, Valvano MA. Distribution and diversity of type VI secretion system clusters in Enterobacter bugandensis and Enterobacter cloacae. Microb Genom 2023; 9:001148. [PMID: 38054968 PMCID: PMC10763514 DOI: 10.1099/mgen.0.001148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/16/2023] [Indexed: 12/07/2023] Open
Abstract
Gram-negative bacteria use type VI secretion systems (T6SSs) to antagonize neighbouring cells. Although primarily involved in bacterial competition, the T6SS is also implicated in pathogenesis, biofilm formation and ion scavenging. Enterobacter species belong to the ESKAPE pathogens, and while their antibiotic resistance has been well studied, less is known about their pathogenesis. Here, we investigated the distribution and diversity of T6SS components in isolates of two clinically relevant Enterobacter species, E. cloacae and E. bugandensis. T6SS clusters are grouped into four types (T6SSi-T6SSiv), of which type i can be further divided into six subtypes (i1, i2, i3, i4a, i4b, i5). Analysis of a curated dataset of 31 strains demonstrated that most of them encode T6SS clusters belonging to the T6SSi type. All T6SS-positive strains possessed a conserved i3 cluster, and many harboured one or two additional i2 clusters. These clusters were less conserved, and some strains displayed evidence of deletion. We focused on a pathogenic E. bugandensis clinical isolate for comprehensive in silico effector prediction, with comparative analyses across the 31 isolates. Several new effector candidates were identified, including an evolved VgrG with a metallopeptidase domain and a Tse6-like protein. Additional effectors included an anti-eukaryotic catalase (KatN), M23 peptidase, PAAR and VgrG proteins. Our findings highlight the diversity of Enterobacter T6SSs and reveal new putative effectors that may be important for the interaction of these species with neighbouring cells and their environment.
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Affiliation(s)
- Amy J. G. Anderson
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, BT9 7BL, UK
| | - Becca Morrell
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, BT9 7BL, UK
| | - Guillermo Lopez Campos
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, BT9 7BL, UK
| | - Miguel A. Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, BT9 7BL, UK
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11
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Zhang N, Ye F, Wang Y, Liu R, Huang Z, Chen C, Liu L, Kang X, Dong S, Rajaofera MJN, Zhu C, Zhang L, Zhou Y, Xiong Y, Xia Q. Role of type VI secretion system protein TssJ-3 in virulence and intracellular survival of Burkholderia pseudomallei. Biochem Biophys Res Commun 2023; 682:397-406. [PMID: 37852065 DOI: 10.1016/j.bbrc.2023.09.091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/26/2023] [Accepted: 09/29/2023] [Indexed: 10/20/2023]
Abstract
TssJ-3 is an outer-membrane lipoprotein and is one of the key components of the type VI secretion system in Burkholderia pseudomallei. TssJ translocates effector proteins to target cells to induce innate immune response in the host. However, the tssJ gene has not been identified in B. pseudomallei and its function in this bacterium has not yet been characterized. tssJ-3 knockout and tssJ-3-complemented B. pseudomallei strains were constructed to determine the effects of tssJ-3 on bacterial growth, biofilm formation, flagellum synthesis, motility, host cell infection, and gene expression in B. pseudomallei. We found that the ΔtssJ-3 mutant strain of B. pseudomallei showed significantly suppressed biofilm formation, flagellum synthesis, bacterial growth, motility, and bacterial invasion into host cells (A549 cells). Furthermore, the ΔtssJ-3 mutation downregulated multiple key genes, including biofilm and flagellum-related genes in B. pseudomallei and induced interleukin-8 gene expression in host cells. These results suggest that tssJ-3, an important gene controlling TssJ-3 protein expression, has regulatory effects on biofilm formation and flagellum synthesis in B. pseudomallei. In addition, B. pseudomallei-derived tssJ-3 contributes to cell infiltration and intracellular replication. This study provides a molecular basis of tssJ-3 for developing therapeutic strategies against B. pseudomallei infections.
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Affiliation(s)
- Nan Zhang
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Fengqin Ye
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Yanshuang Wang
- The Second Affiliated Hospital of Hainan Medical University, China
| | - Rui Liu
- The Second Affiliated Hospital of Hainan Medical University, China
| | - Zhenyan Huang
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Chuizhe Chen
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Lin Liu
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Xun Kang
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Sufang Dong
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Mamy Jayne Nelly Rajaofera
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Chuanlong Zhu
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Liyuan Zhang
- The Second Affiliated Hospital of Hainan Medical University, China
| | - Yanling Zhou
- Department of Pediatrics, The Fourth People's Hospital of Haikou City, China.
| | - Yu Xiong
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China.
| | - Qianfeng Xia
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China.
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12
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De Silva PM, Bennett RJ, Kuhn L, Ngondo P, Debande L, Njamkepo E, Ho B, Weill FX, Marteyn BS, Jenkins C, Baker KS. Escherichia coli killing by epidemiologically successful sublineages of Shigella sonnei is mediated by colicins. EBioMedicine 2023; 97:104822. [PMID: 37806286 PMCID: PMC10579285 DOI: 10.1016/j.ebiom.2023.104822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 10/10/2023] Open
Abstract
BACKGROUND Shigella sp. are enteric pathogens which causes >125 million cases of shigellosis annually. S. sonnei accounts for about a quarter of those cases and is increasingly prevalent in industrialising nations. Being an enteric pathogen, S. sonnei benefits from outcompeting gut commensals such as Escherichia coli to establish itself and cause disease. There are numerous mechanisms that bacterial pathogens use to outcompete its rivals including molecules called colicins. A Type 6 Secretion System (T6SS) was recently described as contributing to E. coli killing in S. sonnei. METHODS We used Bulk Phenotyping of Epidemiological Replicates (BPER) which combined bacterial Genome Wide Association Studies (bGWAS) and high throughput phenotyping on a collection of S. sonnei surveillance isolates to identify the genetic features associated with E. coli killing and explore their relationship with epidemiological behaviour. We further explored the presence of colicins and T6SS components in the isolates using genomics, laboratory experimentation, and proteomics. FINDINGS Our bGWAS analysis returned known and novel colicin and colicin related genes as significantly associated with E. coli killing. In silico analyses identified key colicin clusters responsible for the killing phenotype associated with epidemiologically successful sub-lineages. The killing phenotype was not associated with the presence of a T6SS. Laboratory analyses confirmed the presence of the key colicin clusters and that killing was contact-independent. INTERPRETATION Colicins are responsible for E. coli killing by S. sonnei, not a T6SS. This phenotype contributes to shaping the observed epidemiology of S. sonnei and may contribute to its increasing prevalence globally. BPER is an epidemiologically relevant approach to phenotypic testing that enables the rapid identification of genetic drivers of phenotypic changes, and assessment of their relevance to epidemiology in natural settings. FUNDING Biotechnology and Biological Sciences Research Council, Biotechnology and Biological Sciences Research Council Doctoral Training Partnership studentship, Wellcome Trust, Medical Research Council (UK), French National Research Agency.
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Affiliation(s)
- P Malaka De Silva
- Department of Clinical Infection, Microbiology, and Immunology, Institute for Infection, Veterinary, and Ecological Sciences (IVES), University of Liverpool, Liverpool, United Kingdom
| | - Rebecca J Bennett
- Department of Clinical Infection, Microbiology, and Immunology, Institute for Infection, Veterinary, and Ecological Sciences (IVES), University of Liverpool, Liverpool, United Kingdom
| | - Lauriane Kuhn
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Patryk Ngondo
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000, Strasbourg, France
| | - Lorine Debande
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000, Strasbourg, France
| | - Elisabeth Njamkepo
- Institut Pasteur, Université Paris Cité, Unité des Bactéries pathogènes entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, F-75015, France
| | - Brian Ho
- Institute of Structural and Molecular Biology, University College London and Birkbeck, London, UK
| | - François-Xavier Weill
- Institut Pasteur, Université Paris Cité, Unité des Bactéries pathogènes entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, F-75015, France
| | - Benoît S Marteyn
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000, Strasbourg, France
| | - Claire Jenkins
- Gastro and Food Safety (One Health) Division, UK Health Security Agency, Colindale, London, UK
| | - Kate S Baker
- Department of Clinical Infection, Microbiology, and Immunology, Institute for Infection, Veterinary, and Ecological Sciences (IVES), University of Liverpool, Liverpool, United Kingdom; Department of Genetics, University of Cambridge, Downing Place, Cambridge, UK.
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13
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Kandolo O, Cherrak Y, Filella-Merce I, Le Guenno H, Kosta A, Espinosa L, Santucci P, Verthuy C, Lebrun R, Nilges M, Pellarin R, Durand E. Acinetobacter type VI secretion system comprises a non-canonical membrane complex. PLoS Pathog 2023; 19:e1011687. [PMID: 37769028 PMCID: PMC10564176 DOI: 10.1371/journal.ppat.1011687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 10/10/2023] [Accepted: 09/14/2023] [Indexed: 09/30/2023] Open
Abstract
A. baumannii can rapidly acquire new resistance mechanisms and persist on abiotic surface, enabling the colonization of asymptomatic human host. In Acinetobacter the type VI secretion system (T6SS) is involved in twitching, surface motility and is used for interbacterial competition allowing the bacteria to uptake DNA. A. baumannii possesses a T6SS that has been well studied for its regulation and specific activity, but little is known concerning its assembly and architecture. The T6SS nanomachine is built from three architectural sub-complexes. Unlike the baseplate (BP) and the tail-tube complex (TTC), which are inherited from bacteriophages, the membrane complex (MC) originates from bacteria. The MC is the most external part of the T6SS and, as such, is subjected to evolution and adaptation. One unanswered question on the MC is how such a gigantesque molecular edifice is inserted and crosses the bacterial cell envelope. The A. baumannii MC lacks an essential component, the TssJ lipoprotein, which anchors the MC to the outer membrane. In this work, we studied how A. baumannii compensates the absence of a TssJ. We have characterized for the first time the A. baumannii's specific T6SS MC, its unique characteristic, its membrane localization, and assembly dynamics. We also defined its composition, demonstrating that its biogenesis employs three Acinetobacter-specific envelope-associated proteins that define an intricate network leading to the assembly of a five-proteins membrane super-complex. Our data suggest that A. baumannii has divided the function of TssJ by (1) co-opting a new protein TsmK that stabilizes the MC and by (2) evolving a new domain in TssM for homo-oligomerization, a prerequisite to build the T6SS channel. We believe that the atypical species-specific features we report in this study will have profound implication in our understanding of the assembly and evolutionary diversity of different T6SSs, that warrants future investigation.
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Affiliation(s)
- Ona Kandolo
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS)-UMR 7255, Marseille, France
| | - Yassine Cherrak
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS)-UMR 7255, Marseille, France
| | - Isaac Filella-Merce
- Institut Pasteur, Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Paris, France
- Sorbonne Université, Collège doctoral, Paris, France
| | - Hugo Le Guenno
- Microscopy Core Facility, Aix Marseille Univ, CNRS, Institut de Microbiologie de la Méditerranée, Marseille Cedex 20, France
| | - Artemis Kosta
- Microscopy Core Facility, Aix Marseille Univ, CNRS, Institut de Microbiologie de la Méditerranée, Marseille Cedex 20, France
| | - Leon Espinosa
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
| | - Pierre Santucci
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS)-UMR 7255, Marseille, France
| | - Christophe Verthuy
- Proteomic Core Facility IMM, Marseille Protéomique (MaP), Aix Marseille Univ, Marseille Cedex 20, France
| | - Régine Lebrun
- Proteomic Core Facility IMM, Marseille Protéomique (MaP), Aix Marseille Univ, Marseille Cedex 20, France
| | - Michael Nilges
- Institut Pasteur, Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Paris, France
| | - Riccardo Pellarin
- Institut Pasteur, Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Paris, France
| | - Eric Durand
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS)-UMR 7255, Marseille, France
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Institut National de la Santé et de la Recherche Médicale (INSERM), Marseille, France
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14
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Hug S, Heiniger B, Bolli K, Paszti S, Eberl L, Ahrens CH, Pessi G. Paraburkholderia sabiae Uses One Type VI Secretion System (T6SS-1) as a Powerful Weapon against Notorious Plant Pathogens. Microbiol Spectr 2023; 11:e0162223. [PMID: 37439699 PMCID: PMC10434147 DOI: 10.1128/spectrum.01622-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/21/2023] [Indexed: 07/14/2023] Open
Abstract
Paraburkholderia sabiae LMG24235 is a nitrogen-fixing betaproteobacterium originally isolated from a root nodule of Mimosa caesalpiniifolia in Brazil. We show here that this strain effectively kills strains from several bacterial families (Burkholderiaceae, Pseudomonadaceae, Enterobacteriaceae) which include important plant pathogens in a contact-dependent manner. De novo assembly of the first complete genome of P. sabiae using long sequencing reads and subsequent annotation revealed two gene clusters predicted to encode type VI secretion systems (T6SS), which we named T6SS-1 and T6SS-3 according to previous classification methods (G. Shalom, J. G. Shaw, and M. S. Thomas, Microbiology, 153:2689-2699, 2007, https://doi.org/10.1099/mic.0.2007/006585-0). We created P. sabiae with mutations in each of the two T6SS gene clusters that abrogated their function, and the T6SS-1 mutant was no longer able to outcompete other strains in a contact-dependent manner. Notably, our analysis revealed that T6SS-1 is essential for competition against several important plant pathogens in vitro, including Burkholderia plantarii, Ralstonia solanacearum, Pseudomonas syringae, and Pectobacterium carotovorum. The 9-log reduction in P. syringae cells in the presence of P. sabiae was particularly remarkable. Importantly, in an in vivo assay, P. sabiae was able to protect potato tubers from bacterial soft rot disease caused by P. carotovorum, and this protection was partly dependent on T6SS-1. IMPORTANCE Rhizobia often display additional beneficial traits such as the production of plant hormones and the acquisition of limited essential nutrients that improve plant growth and enhance plant yields. Here, we show that the rhizobial strain P. sabiae antagonizes important phytopathogens such as P. carotovorum, P. syringae, and R. solanacearum and that this effect is due to contact-dependent killing mediated by one of two T6SS systems identified in the complete, de novo assembled genome sequence of P. sabiae. Importantly, co-inoculation of Solanum tuberosum tubers with P. sabiae also resulted in a drastic reduction of soft rot caused by P. carotovorum in an in vivo model system. This result highlights the protective potential of P. sabiae against important bacterial plant diseases, which makes it a valuable candidate for application as a biocontrol agent. It also emphasizes the particular potential of rhizobial inoculants that combine several beneficial effects such as plant growth promotion and biocontrol for sustainable agriculture.
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Affiliation(s)
- Sebastian Hug
- Department of Plant and Microbial Biology, University of Zürich, Zurich, Switzerland
| | - Benjamin Heiniger
- Agroscope – Molecular Ecology, Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Kim Bolli
- Department of Plant and Microbial Biology, University of Zürich, Zurich, Switzerland
| | - Sarah Paszti
- Department of Plant and Microbial Biology, University of Zürich, Zurich, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zürich, Zurich, Switzerland
| | - Christian H. Ahrens
- Agroscope – Molecular Ecology, Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Gabriella Pessi
- Department of Plant and Microbial Biology, University of Zürich, Zurich, Switzerland
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15
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Katz A, Porte L, Weitzel T, Varela C, Muñoz-Rehbein C, Ugalde JA, Grim C, González-Escalona N, Blondel CJ, Bravo V. Whole-genome sequencing reveals changes in genomic diversity and distinctive repertoires of T3SS and T6SS effector candidates in Chilean clinical Campylobacter strains. Front Cell Infect Microbiol 2023; 13:1208825. [PMID: 37520433 PMCID: PMC10374022 DOI: 10.3389/fcimb.2023.1208825] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 06/16/2023] [Indexed: 08/01/2023] Open
Abstract
Campylobacter is the leading cause of bacterial gastroenteritis worldwide and an emerging and neglected pathogen in South America. This zoonotic pathogen colonizes the gastrointestinal tract of a wide range of mammals and birds, with poultry as the most important reservoir for human infections. Apart from its high morbidity rates, the emergence of resistant strains is of global concern. The aims of this work were to determine genetic diversity, presence of antimicrobial resistance determinants and virulence potential of Campylobacter spp. isolated from patients with acute gastrointestinal disease at 'Clinica Alemana', Santiago de Chile. The study considered the isolation of Campylobacter spp., from stool samples during a 20-month period (January 2020 to September 2021). We sequenced (NextSeq, Illumina) and performed an in-depth analysis of the genome sequences of 88 Campylobacter jejuni and 2 Campylobacter coli strains isolated from clinical samples in Chile. We identified a high genetic diversity among C. jejuni strains and the emergence of prevalent clonal complexes, which were not identified in our previous reports. While ~40% of strains harbored a mutation in the gyrA gene associated with fluoroquinolone resistance, no macrolide-resistance determinants were detected. Interestingly, gene clusters encoding virulence factors such as the T6SS or genes associated with long-term sequelae such as Guillain-Barré syndrome showed lineage-relatedness. In addition, our analysis revealed a high degree of variability regarding the presence of fT3SS and T6SS effector proteins in comparison to type strains 81-176, F38011, and NCTC 11168 and 488. Our study provides important insights into the molecular epidemiology of this emerging foodborne pathogen. In addition, the differences observed regarding the repertoire of fT3SS and T6SS effector proteins could have an impact on the pathogenic potential and transmissibility of these Latin American isolates, posing another challenge in characterizing the infection dynamics of this emergent and neglected bacterial pathogen.
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Affiliation(s)
- Assaf Katz
- Programa de Biología Celular y Molecular, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Lorena Porte
- Laboratorio Clínico, Clínica Alemana de Santiago, Facultad de Medicina, Clínica Alemana, Universidad del Desarrollo, Santiago, Chile
| | - Thomas Weitzel
- Laboratorio Clínico, Clínica Alemana de Santiago, Facultad de Medicina, Clínica Alemana, Universidad del Desarrollo, Santiago, Chile
- Instituto de Ciencias e Innovación en Medicina (ICIM), Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile
| | - Carmen Varela
- Laboratorio Clínico, Clínica Alemana de Santiago, Facultad de Medicina, Clínica Alemana, Universidad del Desarrollo, Santiago, Chile
| | - Cristina Muñoz-Rehbein
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Juan A. Ugalde
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Christopher Grim
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD, United States
| | - Narjol González-Escalona
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD, United States
| | - Carlos J. Blondel
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Verónica Bravo
- Centro de Investigaciones Biomédicas y Aplicadas (CIBAP), Escuela de Medicina, Facultad de Ciencias Médicas, Universidad de Santiago de Chile, Santiago, Chile
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16
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Lin YL, Smith SN, Kanso E, Septer AN, Rycroft CH. A subcellular biochemical model for T6SS dynamics reveals winning competitive strategies. PNAS NEXUS 2023; 2:pgad195. [PMID: 37441614 PMCID: PMC10335733 DOI: 10.1093/pnasnexus/pgad195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 07/15/2023]
Abstract
The type VI secretion system (T6SS) is a broadly distributed interbacterial weapon that can be used to eliminate competing bacterial populations. Although unarmed target populations are typically used to study T6SS function in vitro, bacteria most likely encounter other T6SS-armed competitors in nature. However, the connection between subcellular details of the T6SS and the outcomes of such mutually lethal battles is not well understood. Here, we incorporate biological data derived from natural competitors of Vibrio fischeri light organ symbionts to build a biochemical model for T6SS at the single-cell level, which we then integrate into an agent-based model (ABM). Using the ABM, we isolate and experiment with strain-specific physiological differences between competitors in ways not possible with biological samples to identify winning strategies for T6SS-armed populations. Through in vitro experiments, we discover that strain-specific differences exist in T6SS activation speed. ABM simulations corroborate that faster activation is dominant in determining survival during competition. Once competitors are fully activated, the energy required for T6SS creates a tipping point where increased weapon building and firing becomes too costly to be advantageous. Through ABM simulations, we identify the threshold where this transition occurs in the T6SS parameter space. We also find that competitive outcomes depend on the geometry of the battlefield: unarmed target cells survive at the edges of a range expansion where unlimited territory can be claimed. Alternatively, competitions within a confined space, much like the light organ crypts where natural V. fischeri compete, result in the rapid elimination of the unarmed population.
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Affiliation(s)
| | | | - Eva Kanso
- Department of Aerospace and Mechanical Engineering, University of Southern California, 3650 McClintock Ave, Los Angeles, CA 90089, USA
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17
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Prince A, Wong Fok Lung T. Immunometabolic control by Klebsiella pneumoniae. IMMUNOMETABOLISM (COBHAM, SURREY) 2023; 5:e00028. [PMID: 37492184 PMCID: PMC10364963 DOI: 10.1097/in9.0000000000000028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 06/27/2023] [Indexed: 07/27/2023]
Abstract
Klebsiella pneumoniae is a common Gram-negative pathogen associated with community-acquired and healthcare-associated infections. Its ability to acquire genetic elements resulted in its rapid development of resistance to virtually all antimicrobial agents. Once infection is established, K. pneumoniae is able to evade the host immune response and perhaps more importantly, undergo metabolic rewiring to optimize its ability to maintain infection. K. pneumoniae lipopolysaccharide and capsular polysaccharide are central factors in the induction and evasion of immune clearance. Less well understood is the importance of immunometabolism, the intersection between cellular metabolism and immune function, in the host response to K. pneumoniae infection. Bacterial metabolism itself is perceived as a metabolic stress to the host, altering the microenvironment at the site of infection. In this review, we will discuss the metabolic responses induced by K. pneumoniae, particularly in response to stimulation with the metabolically active bacteria versus pathogen-associated molecular patterns alone, and their implications in shaping the nature of the immune response and the infection outcome. A better understanding of the immunometabolic response to K. pneumoniae may help identify new targets for therapeutic intervention in the treatment of multidrug-resistant bacterial infections.
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Affiliation(s)
- Alice Prince
- Department of Pediatrics, Columbia University, New York, NY, USA
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18
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Calder A, Snyder LAS. Diversity of the type VI secretion systems in the Neisseria spp. Microb Genom 2023; 9. [PMID: 37052605 DOI: 10.1099/mgen.0.000986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023] Open
Abstract
Complete Type VI Secretion Systems were identified in the genome sequence data of Neisseria subflava isolates sourced from throat swabs of human volunteers. The previous report was the first to describe two complete Type VI Secretion Systems in these isolates, both of which were distinct in terms of their gene organization and sequence homology. Since publication of the first report, Type VI Secretion System subtypes have been identified in Neisseria spp. The characteristics of each type in N. subflava are further investigated here and in the context of the other Neisseria spp., including identification of the lineages containing the different types and subtypes. Type VI Secretion Systems use VgrG for delivery of toxin effector proteins; several copies of vgrG and associated effector / immunity pairs are present in Neisseria spp. Based on sequence similarity between strains and species, these core Type VI Secretion System genes, vgrG, and effector / immunity genes may diversify via horizontal gene transfer, an instrument for gene acquisition and repair in Neisseria spp.
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Affiliation(s)
- Alan Calder
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Penrhyn Road, Kingston upon Thames, KT1 2EE, UK
| | - Lori A S Snyder
- School of Life Sciences, Pharmacy, and Chemistry, Kingston University, Penrhyn Road, Kingston upon Thames, KT1 2EE, UK
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Abstract
Many Gram-negative bacteria deploy a type VI secretion system (T6SS) to inject toxins into target cells to promote their survival and replication in complex environments. Here, we report that Acinetobacter baumannii uses its T6SS to kill fungi and that the effector TafE (ACX60_15365) is responsible for such killing. Although ectopically expressed TafE is toxic to both Escherichia coli and Saccharomyces cerevisiae, deletion of tafE only affects the antifungal activity of A. baumannii. We demonstrate that TafE is a DNase capable of targeting the nuclei of yeast cells and that an Ntox15 domain is essential for its ability to degrade DNA. Furthermore, our findings show that A. baumannii is protected from the toxicity of TafE by elaborating the immunity protein TaeI (ACX60_15360), which antagonizes the activity of the effector by direct binding. The discovery of A. baumannii T6SS effectors capable of killing multiple taxonomically distinct microbes has shed light on a mechanism of the high-level fitness of this pathogen in environments characterized by scarce nutrients and the potential presence of diverse microorganisms. IMPORTANCE Acinetobacter baumannii is an increasing important nosocomial pathogen that is difficult to combat due to its ability to survive in harsh environments and the emergence of isolates that are resistant to multiple antibiotics. A better understanding of the mechanism underlying the toughness of A. baumannii may identify its Achilles' heel, which will facilitate the development of novel preventive and treatment measures. In this study, our findings show that A. baumannii kills fungi with the DNase effector TafE injected into competitor cells by its type VI secretion system. A. baumannii is protected from the activity of TafE by the immunity protein TaeI, which inactivates the effector by direct binding. Our results suggest that inactivation of its T6SS or effectors may reduce the fitness of A. baumannii and increase the effectiveness of treatment by means such as antibiotics. Furthermore, our finding suggests that targeted degradation of TaeI may be an effective strategy to kill A. baumannii.
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20
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Type VI Secretion Systems: Environmental and Intra-host Competition of Vibrio cholerae. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:41-63. [PMID: 36792870 DOI: 10.1007/978-3-031-22997-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The Vibrio Type VI Secretion System (T6SS) is a harpoon-like nanomachine that serves as a defense system and is encoded by approximately 25% of all gram-negative bacteria. In this chapter, we describe the structure of the T6SS in different Vibrio species and outline how the use of different T6SS effector and immunity proteins control kin selection. We summarize the genetic loci that encode the structural elements that make up the Vibrio T6SSs and how these gene clusters are regulated. Finally, we provide insights into T6SS-based competitive dynamics, the role of T6SS genetic exchange in those competitive dynamics, and roles for the Vibrio T6SS in virulence.
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Santoriello FJ, Kirchberger PC, Boucher Y, Pukatzki S. Pandemic Vibrio cholerae acquired competitive traits from an environmental Vibrio species. Life Sci Alliance 2023; 6:6/2/e202201437. [PMID: 36446527 PMCID: PMC9711863 DOI: 10.26508/lsa.202201437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 11/05/2022] [Accepted: 11/07/2022] [Indexed: 11/30/2022] Open
Abstract
Vibrio cholerae is a human pathogen that thrives in estuarine environments. Within the environment and human host, V. cholerae uses the type VI secretion system (T6SS) to inject toxic effectors into neighboring microbes and to establish its replicative niche. V. cholerae strains encode a wide variety of horizontally shared effectors, but pandemic isolates encode an identical set of distinct effectors. Effector set retention in pandemic strains despite mobility between disparate strains suggests that horizontal acquisition of these effectors was crucial for evolving pandemic V. cholerae We attempted to locate the donor of the pandemic effectors to V. cholerae To this end, we identified potential gene transfer events of the pandemic-associated T6SS clusters between a fish pathogen, Vibrio anguillarum, and V. cholerae We supported the likelihood of interaction between these species by demonstrating that homologous effector-immunity pairs from V. cholerae and V. anguillarum can cross-neutralize one another. Thus, V. anguillarum constitutes an environmental reservoir of pandemic-associated V. cholerae T6SS effectors that may have initially facilitated competition between pre-pandemic V. cholerae and V. anguillarum for an environmental niche.
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Affiliation(s)
- Francis J Santoriello
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Department of Biology, The City College of New York, New York, NY, USA
| | - Paul C Kirchberger
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Yann Boucher
- Saw Swee Hock School of Public Health and National University Hospital System, National University of Singapore, Singapore, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, National University of Singapore, Singapore, Singapore.,Infectious Diseases Translational Research Program, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore and National University Hospital System, Singapore, Singapore
| | - Stefan Pukatzki
- Department of Biology, The City College of New York, New York, NY, USA
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22
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Kumari K, Sharma PK, Singh RP. Unraveling the Virulence Factors and Secreted Proteins of an Environmental Isolate Enterobacter sp. S-16. Curr Microbiol 2023; 80:88. [PMID: 36719538 DOI: 10.1007/s00284-023-03197-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 01/19/2023] [Indexed: 02/01/2023]
Abstract
Members of the Enterobacter genus include many pathogenic microbes of humans and plants, secrete proteins that contribute to the interactions of bacteria and their environment. Therefore, understanding of secreted proteins is vital to understand bacterial physiology and behavior. Here, we explored the secretome of an environmental isolate Enterobacter sp. S-16 by nanoLC-MS/MS and identified 572 proteins in the culture supernatant. Gene ontology (GO) analysis indicated that proteins were related to biological processes, molecular as well as cellular functions. The majority of the identified proteins are involved in microbial metabolism, chemotaxis & motility, flagellar hook-associated proteins, biosynthesis of antibiotics, and molecular chaperones to assist the protein folding. Bioinformatics analysis of the secretome revealed the presence of type I and type VI secretion system proteins. Presence of these diverse secretion system proteins in Enterobacter sp. S-16 are likely to be involved in the transport of various proteins including nutrient acquisition, adhesion, colonization, and homeostasis maintenance. Among the secreted bacterial proteins with industrial importance, lignocellulolytic enzymes play a major role, therefore, we analyzed our secretome results for any presence of glycoside hydrolases (GHs) and other hydrolytic enzymes (CAZymes). Overall, the secreted proteins may be considered an attractive reservoir of potential antigens for drug development, diagnostic markers, and other biomedical applications.
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Affiliation(s)
- Kiran Kumari
- Department of Bioengineering and Biotechnology, BIT Mesra, Ranchi, Jharkhand, 835215, India
| | - Parva Kumar Sharma
- Department of Plant Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742, USA
| | - Rajnish Prakash Singh
- Department of Bioengineering and Biotechnology, BIT Mesra, Ranchi, Jharkhand, 835215, India.
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23
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Vanlioğlu E, Santin YG, Filella-Merce I, Pellarin R, Cascales E. Coevolution-Guided Mapping of the Type VI Secretion Membrane Complex-Baseplate Interface. J Mol Biol 2023; 435:167918. [PMID: 36509161 DOI: 10.1016/j.jmb.2022.167918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
The type VI secretion system (T6SS) is a multiprotein weapon evolved by Gram-negative bacteria to deliver effectors into eukaryotic cells or bacterial rivals. The T6SS uses a contractile mechanism to propel an effector-loaded needle into its target. The contractile tail is built on an assembly platform, the baseplate, which is anchored to a membrane complex. Baseplate-membrane complex interactions are mainly mediated by contacts between the C-terminal domain of the TssK baseplate component and the cytoplasmic domain of the TssL inner membrane protein. Currently, the structural details of this interaction are unknown due to the marginal stability of the TssK-TssL complex. Here we conducted a mutagenesis study based on putative TssK-TssL contact pairs identified by co-evolution analyses. We then evaluated the impact of these mutations on T6SS activity, TssK-TssL interaction and sheath assembly and dynamics in enteroaggregative Escherichia coli. Finally, we probed the TssK-TssL interface by disulfide cross-linking, allowing to propose a model for the baseplate-membrane complex interface.
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Affiliation(s)
- Etienne Vanlioğlu
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), CNRS - Aix-Marseille Université UMR7255, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Yoann G Santin
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), CNRS - Aix-Marseille Université UMR7255, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Isaac Filella-Merce
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR 3528, 28 rue du Docteur Roux, 75015 Paris, France
| | - Riccardo Pellarin
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR 3528, 28 rue du Docteur Roux, 75015 Paris, France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), CNRS - Aix-Marseille Université UMR7255, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France.
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24
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Sun Z, Heacock-Kang Y, McMillan IA, Cabanas D, Zarzycki-Siek J, Hoang TT. A virulence activator of a surface attachment protein in Burkholderia pseudomallei acts as a global regulator of other membrane-associated virulence factors. Front Microbiol 2023; 13:1063287. [PMID: 36726566 PMCID: PMC9884982 DOI: 10.3389/fmicb.2022.1063287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/30/2022] [Indexed: 01/19/2023] Open
Abstract
Burkholderia pseudomallei (Bp), causing a highly fatal disease called melioidosis, is a facultative intracellular pathogen that attaches and invades a variety of cell types. We previously identified BP1026B_I0091 as a surface attachment protein (Sap1) and an essential virulence factor, contributing to Bp pathogenesis in vitro and in vivo. The expression of sap1 is regulated at different stages of Bp intracellular lifecycle by unidentified regulator(s). Here, we identified SapR (BP1026B_II1046) as a transcriptional regulator that activates sap1, using a high-throughput transposon mutagenesis screen in combination with Tn-Seq. Consistent with phenotypes of the Δsap1 mutant, the ΔsapR activator mutant exhibited a significant reduction in Bp attachment to the host cell, leading to subsequent decreased intracellular replication. RNA-Seq analysis further revealed that SapR regulates sap1. The regulation of sap1 by SapR was confirmed quantitatively by qRT-PCR, which also validated the RNA-Seq data. SapR globally regulates genes associated with the bacterial membrane in response to diverse environments, and some of the genes regulated by SapR are virulence factors that are required for Bp intracellular infection (e.g., type III and type VI secretion systems). This study has identified the complex SapR regulatory network and its importance as an activator of an essential Sap1 attachment factor.
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Affiliation(s)
- Zhenxin Sun
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Yun Heacock-Kang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Ian A McMillan
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Darlene Cabanas
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Jan Zarzycki-Siek
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Tung T Hoang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, United States
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25
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Gabbert AD, Mydosh JL, Talukdar PK, Gloss LM, McDermott JE, Cooper KK, Clair GC, Konkel ME. The Missing Pieces: The Role of Secretion Systems in Campylobacter jejuni Virulence. Biomolecules 2023; 13:135. [PMID: 36671522 PMCID: PMC9856085 DOI: 10.3390/biom13010135] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 12/29/2022] [Accepted: 01/05/2023] [Indexed: 01/10/2023] Open
Abstract
Campylobacter jejuni is likely the most common bacterial cause of gastroenteritis worldwide, responsible for millions of cases of inflammatory diarrhea characterized by severe abdominal cramps and blood in the stool. Further, C. jejuni infections are associated with post-infection sequelae in developed countries and malnutrition and growth-stunting in low- and middle-income countries. Despite the increasing prevalence of the disease, campylobacteriosis, and the recognition that this pathogen is a serious health threat, our understanding of C. jejuni pathogenesis remains incomplete. In this review, we focus on the Campylobacter secretion systems proposed to contribute to host-cell interactions and survival in the host. Moreover, we have applied a genomics approach to defining the structural and mechanistic features of C. jejuni type III, IV, and VI secretion systems. Special attention is focused on the flagellar type III secretion system and the prediction of putative effectors, given that the proteins exported via this system are essential for host cell invasion and the inflammatory response. We conclude that C. jejuni does not possess a type IV secretion system and relies on the type III and type VI secretion systems to establish a niche and potentiate disease.
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Affiliation(s)
- Amber D. Gabbert
- School of Molecular Biosciences, College of Veterinary Sciences, Washington State University, Pullman, WA 99164, USA
| | - Jennifer L. Mydosh
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ 85721, USA
| | - Prabhat K. Talukdar
- School of Molecular Biosciences, College of Veterinary Sciences, Washington State University, Pullman, WA 99164, USA
| | - Lisa M. Gloss
- School of Molecular Biosciences, College of Veterinary Sciences, Washington State University, Pullman, WA 99164, USA
| | - Jason E. McDermott
- Integrative Omics, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Kerry K. Cooper
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ 85721, USA
| | - Geremy C. Clair
- Integrative Omics, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Michael E. Konkel
- School of Molecular Biosciences, College of Veterinary Sciences, Washington State University, Pullman, WA 99164, USA
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26
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Robinson LA, Collins ACZ, Murphy RA, Davies JC, Allsopp LP. Diversity and prevalence of type VI secretion system effectors in clinical Pseudomonas aeruginosa isolates. Front Microbiol 2023; 13:1042505. [PMID: 36687572 PMCID: PMC9846239 DOI: 10.3389/fmicb.2022.1042505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 11/23/2022] [Indexed: 01/06/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen and a major driver of morbidity and mortality in people with Cystic Fibrosis (CF). The Type VI secretion system (T6SS) is a molecular nanomachine that translocates effectors across the bacterial membrane into target cells or the extracellular environment enabling intermicrobial interaction. P. aeruginosa encodes three T6SS clusters, the H1-, H2- and H3-T6SS, and numerous orphan islands. Genetic diversity of T6SS-associated effectors in P. aeruginosa has been noted in reference strains but has yet to be explored in clinical isolates. Here, we perform a comprehensive bioinformatic analysis of the pangenome and T6SS effector genes in 52 high-quality clinical P. aeruginosa genomes isolated from CF patients and housed in the Personalised Approach to P. aeruginosa strain repository. We confirm that the clinical CF isolate pangenome is open and principally made up of accessory and unique genes that may provide strain-specific advantages. We observed genetic variability in some effector/immunity encoding genes and show that several well-characterised vgrG and PAAR islands are absent from numerous isolates. Our analysis shows clear evidence of disruption to T6SS genomic loci through transposon, prophage, and mobile genetic element insertions. We identified an orphan vgrG island in P. aeruginosa strain PAK and five clinical isolates using in silico analysis which we denote vgrG7, predicting a gene within this cluster to encode a Tle2 lipase family effector. Close comparison of T6SS loci in clinical isolates compared to reference P. aeruginosa strain PAO1 revealed the presence of genes encoding eight new T6SS effectors with the following putative functions: cytidine deaminase, lipase, metallopeptidase, NADase, and pyocin. Finally, the prevalence of characterised and putative T6SS effectors were assessed in 532 publicly available P. aeruginosa genomes, which suggests the existence of accessory effectors. Our in silico study of the P. aeruginosa T6SS exposes a level of genetic diversity at T6SS genomic loci not seen to date within P. aeruginosa, particularly in CF isolates. As understanding the effector repertoire is key to identifying the targets of T6SSs and its efficacy, this comprehensive analysis provides a path for future experimental characterisation of these mediators of intermicrobial competition and host manipulation.
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Affiliation(s)
- Luca A. Robinson
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Alice C. Z. Collins
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Ronan A. Murphy
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Jane C. Davies
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Department of Paediatric Respiratory Medicine, Royal Brompton Hospital, London, United Kingdom
| | - Luke P. Allsopp
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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27
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Yang Y, Pan D, Tang Y, Li J, Zhu K, Yu Z, Zhu L, Wang Y, Chen P, Li C. H3-T6SS of Pseudomonas aeruginosa PA14 contributes to environmental adaptation via secretion of a biofilm-promoting effector. STRESS BIOLOGY 2022; 2:55. [PMID: 37676573 PMCID: PMC10442045 DOI: 10.1007/s44154-022-00078-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 12/11/2022] [Indexed: 09/08/2023]
Abstract
Microbial species often occur in complex communities and exhibit intricate synergistic and antagonistic interactions. To avoid predation and compete for favorable niches, bacteria have evolved specialized protein secretion systems. The type VI secretion system (T6SS) is a versatile secretion system widely distributed among Gram-negative bacteria that translocates effectors into target cells or the extracellular milieu via various physiological processes. Pseudomonas aeruginosa is an opportunistic pathogen responsible for many diseases, and it has three independent T6SSs (H1-, H2-, and H3-T6SS). In this study, we found that the H3-T6SS of highly virulent P. aeruginosa PA14 is negatively regulated by OxyR and OmpR, which are global regulatory proteins of bacterial oxidative and acid stress. In addition, we identified a H3-T6SS effector PA14_33970, which is located upstream of VgrG3. PA14_33970 interacted directly with VgrG3 and translocated into host cells. Moreover, we found that H3-T6SS and PA14_33970 play crucial roles in oxidative, acid, and osmotic stress resistance, as well as in motility and biofilm formation. PA14_33970 was identified as a new T6SS effector promoting biofilm formation and thus named TepB. Furthermore, we found that TepB contributes to the virulence of P. aeruginosa PA14 toward Caenorhabditis elegans. Overall, our study indicates that H3-T6SS and its biofilm-promoting effector TepB are regulated by OxyR and OmpR, both of which are important for adaptation of P. aeruginosa PA14 to multiple stressors, providing insights into the regulatory mechanisms and roles of T6SSs in P. aeruginosa.
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Affiliation(s)
- 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, Yangling, 712100, Shaanxi, China
| | - Damin 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, Yangling, 712100, Shaanxi, China
| | - Yanan Tang
- 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, 712100, Shaanxi, China
| | - Jiali Li
- 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, 712100, Shaanxi, China
| | - Kaixiang Zhu
- 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, 712100, Shaanxi, China
| | - Zonglan Yu
- 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, 712100, Shaanxi, China
| | - Lingfang Zhu
- 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, 712100, Shaanxi, China
| | - 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, Yangling, 712100, Shaanxi, China
| | - Peng Chen
- 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, 712100, Shaanxi, China.
| | - Changfu Li
- 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, 712100, Shaanxi, China.
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28
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Robinson L, Liaw J, Omole Z, Corcionivoschi N, Hachani A, Gundogdu O. In silico investigation of the genus Campylobacter type VI secretion system reveals genetic diversity in organization and putative effectors. Microb Genom 2022; 8:mgen000898. [PMID: 36314601 PMCID: PMC9676060 DOI: 10.1099/mgen.0.000898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 09/11/2022] [Indexed: 01/25/2023] Open
Abstract
Bacterial type VI secretion systems (T6SSs) are contractile nanomachines that deliver proteinic substrates into target prokaryotic or eukaryotic cells and the surrounding milieu. The genus Campylobacter encompasses 39 recognized species and 13 subspecies, with many belonging to a group known as ‘emerging Campylobacter pathogens’. Within Campylobacter , seven species have been identified to harbour a complete T6SS cluster but have yet to be comparatively assessed. In this study, using systematic bioinformatics approaches and the T6SS-positive Campylobacter jejuni 488 strain as a reference, we explored the genus-wide prevalence, similarity and make-up of the T6SS amongst 372 publicly available ‘complete’ Campylobacter genomes. Our analyses predict that approximately one-third of Campylobacter species possess a T6SS. We also putatively report the first identification of a T6SS in four species: Campylobacter cuniculorum, Campylobacter helveticus, Campylobacter armoricus and Campylobacter ornithocola . The Campylobacter T6SSs cluster into three distinct organizations (I–III), of which two break down into further variants. Thirty T6SS-containing genomes were found to harbour more than one vgrG gene, with Campylobacter lari strain NCTC 11845 possessing five. Analysis of the C. jejuni Pathogenicity Island-1 confirmed its conservation amongst T6SS-positive C. jejuni strains, as well as highlighting its diverse genetic composition, including additional putative effector–immunity pairs (e.g. PoNe and DUF1911 domains). Effector–immunity pairs were also observed neighbouring vgrG s in several other Campylobacter species, in addition to putative genes encoding nucleases, lysozymes, ATPases and a ferric ATP-binding cassette uptake system. These observations highlight the diverse genetic make-up of the T6SS within Campylobacter and provide further evidence of its role in pathogenesis.
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Affiliation(s)
- Luca Robinson
- National Heart and Lung Institute, Imperial College London, London, UK
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Janie Liaw
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Zahra Omole
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Nicolae Corcionivoschi
- Bacteriology Branch, Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, UK
- Bioengineering of Animal Resources, University of Life Sciences – King Mihai I of Romania from Timisoara, Timisoara, Romania
| | - Abderrahman Hachani
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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29
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The Antivirulence Activity of Umbelliferone and Its Protective Effect against A. hydrophila-Infected Grass Carp. Int J Mol Sci 2022; 23:ijms231911119. [PMID: 36232424 PMCID: PMC9569924 DOI: 10.3390/ijms231911119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 11/17/2022] Open
Abstract
A. hydrophila is an important pathogen that mainly harms aquatic animals and has exhibited resistance to a variety of antibiotics. Here, to seek an effective alternative for antibiotics, the effects of umbelliferone (UM) at sub-MICs on A. hydrophila virulence factors and the quorum-sensing system were studied. Subsequently, RNA sequencing was employed to explore the potential mechanisms for the antivirulence activity of umbelliferone. Meanwhile, the protective effect of umbelliferone on grass carp infected with A. hydrophila was studied in vivo. Our results indicated that umbelliferone could significantly inhibit A. hydrophila virulence such as hemolysis, biofilm formation, swimming and swarming motility, and their quorum-sensing signals AHL and AI-2. Transcriptomic analysis showed that umbelliferone downregulated expression levels of genes related to exotoxin, the secretory system (T2SS and T6SS), iron uptake, etc. Animal studies demonstrated that umbelliferone could significantly improve the survival of grass carps infected with A. hydrophila, reduce the bacterial load in the various tissues, and ameliorate cardiac, splenic, and hepatopancreas injury. Collectively, umbelliferone can reduce the pathogenicity of A. hydrophila and is a potential drug for treating A. hydrophila infection.
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30
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Nennig M, Clément A, Longueval E, Bernardi T, Ragimbeau C, Tresse O. Metaphenotypes associated with recurrent genomic lineages of Campylobacter jejuni responsible for human infections in Luxembourg. Front Microbiol 2022; 13:901192. [PMID: 36160185 PMCID: PMC9490421 DOI: 10.3389/fmicb.2022.901192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Campylobacter jejuni is a leading cause of foodborne illnesses worldwide. Although considered fragile, this microaerophilic bacterium is able to survive in various challenging environments, which subsequently constitutes multiple sources of transmission for human infection. To test the assumption of acquiring specific features for adaptation and survival, we established a workflow of phenotypic tests related to the survival and the persistence of recurrent and sporadic strains. A representative collection of 83 strains isolated over 13 years from human, mammal, poultry, and environmental sources in Luxembourg, representing different spreading patterns (endemic, epidemic, and sporadic), was screened for survival to oxidative stresses, for acclimating to aerobic conditions (AC), and for persistence on abiotic surfaces. Using the cgMLST Oxford typing scheme for WGS data, the collection was classified into genomic lineages corresponding to host-generalist strains (lineages A and D, CC ST-21), host-specific strains (lineage B, CC ST-257 and lineage C, CC ST-464) and sporadic strains. We established that when a strain survives concentrations beyond 0.25 mM superoxide stress, it is six times more likely to survive hyperoxide stress and that a highly adherent strain is 14 times more likely to develop a biofilm. Surprisingly, more than half of the strains could acclimate to AC but this capacity does not explain the difference between recurrent genomic lineages and sporadic strains and the survival to oxidative stresses, while recurrent strains have a significantly higher adhesion/biofilm formation capacity than sporadic ones. From this work, the genomic lineages with more stable genomes could be characterized by a specific combination of phenotypes, called metaphenotypes. From the functional genomic analyses, the presence of a potentially functional T6SS in the strains of lineage D might explain the propensity of these strains to be strong biofilm producers. Our findings support the hypothesis that phenotypical abilities contribute to the spatio-temporal adaptation and survival of stable genomic lineages. It suggests a selection of better-adapted and persistent strains in challenging stress environments, which could explain the prevalence of these lineages in human infections.
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Affiliation(s)
- Morgane Nennig
- Epidemiology and Microbial Genomics, Laboratoire National de Santé, Dudelange, Luxembourg
- UMR-1280 PhAN, INRAE, Nantes, France
| | - Arnaud Clément
- BioFilm Control, Biopôle Clermont-Limagne, Saint-Beauzire, France
| | - Emmanuelle Longueval
- Epidemiology and Microbial Genomics, Laboratoire National de Santé, Dudelange, Luxembourg
| | - Thierry Bernardi
- BioFilm Control, Biopôle Clermont-Limagne, Saint-Beauzire, France
| | - Catherine Ragimbeau
- Epidemiology and Microbial Genomics, Laboratoire National de Santé, Dudelange, Luxembourg
- *Correspondence: Catherine Ragimbeau,
| | - Odile Tresse
- UMR-1280 PhAN, INRAE, Nantes, France
- Odile Tresse,
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31
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Pseudomonas aeruginosa: pathogenesis, virulence factors, antibiotic resistance, interaction with host, technology advances and emerging therapeutics. Signal Transduct Target Ther 2022; 7:199. [PMID: 35752612 PMCID: PMC9233671 DOI: 10.1038/s41392-022-01056-1] [Citation(s) in RCA: 226] [Impact Index Per Article: 113.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 06/04/2022] [Accepted: 06/08/2022] [Indexed: 02/05/2023] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) is a Gram-negative opportunistic pathogen that infects patients with cystic fibrosis, burn wounds, immunodeficiency, chronic obstructive pulmonary disorder (COPD), cancer, and severe infection requiring ventilation, such as COVID-19. P. aeruginosa is also a widely-used model bacterium for all biological areas. In addition to continued, intense efforts in understanding bacterial pathogenesis of P. aeruginosa including virulence factors (LPS, quorum sensing, two-component systems, 6 type secretion systems, outer membrane vesicles (OMVs), CRISPR-Cas and their regulation), rapid progress has been made in further studying host-pathogen interaction, particularly host immune networks involving autophagy, inflammasome, non-coding RNAs, cGAS, etc. Furthermore, numerous technologic advances, such as bioinformatics, metabolomics, scRNA-seq, nanoparticles, drug screening, and phage therapy, have been used to improve our understanding of P. aeruginosa pathogenesis and host defense. Nevertheless, much remains to be uncovered about interactions between P. aeruginosa and host immune responses, including mechanisms of drug resistance by known or unannotated bacterial virulence factors as well as mammalian cell signaling pathways. The widespread use of antibiotics and the slow development of effective antimicrobials present daunting challenges and necessitate new theoretical and practical platforms to screen and develop mechanism-tested novel drugs to treat intractable infections, especially those caused by multi-drug resistance strains. Benefited from has advancing in research tools and technology, dissecting this pathogen's feature has entered into molecular and mechanistic details as well as dynamic and holistic views. Herein, we comprehensively review the progress and discuss the current status of P. aeruginosa biophysical traits, behaviors, virulence factors, invasive regulators, and host defense patterns against its infection, which point out new directions for future investigation and add to the design of novel and/or alternative therapeutics to combat this clinically significant pathogen.
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Le Goff M, Vastel M, Lebrun R, Mansuelle P, Diarra A, Grandjean T, Triponney P, Imbert G, Gosset P, Dessein R, Garnier F, Durand E. Characterization of the Achromobacter xylosoxidans Type VI Secretion System and Its Implication in Cystic Fibrosis. Front Cell Infect Microbiol 2022; 12:859181. [PMID: 35782124 PMCID: PMC9245596 DOI: 10.3389/fcimb.2022.859181] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
Bacteria of the genus Achromobacter are environmental germs, with an unknown reservoir. It can become opportunistic pathogens in immunocompromised patients, causing bacteremia, meningitis, pneumonia, or peritonitis. In recent years, Achromobacter xylosoxidans has emerged with increasing incidence in patients with cystic fibrosis (CF). Recent studies showed that A. xylosoxidans is involved in the degradation of the respiratory function of patients with CF. The respiratory ecosystem of patients with CF is colonized by bacterial species that constantly fight for space and access to nutrients. The type VI secretion system (T6SS) empowers this constant bacterial antagonism, and it is used as a virulence factor in several pathogenic bacteria. This study aimed to investigate the prevalence of the T6SS genes in A. xylosoxidans isolated in patients with CF. We also evaluated clinical and molecular characteristics of T6SS-positive A. xylosoxidans strains. We showed that A. xylosoxidans possesses a T6SS gene cluster and that some environmental and clinical isolates assemble a functional T6SS nanomachine. A. xylosoxidans T6SS is used to target competing bacteria, including other CF-specific pathogens. Finally, we demonstrated the importance of the T6SS in the internalization of A. xylosoxidans in lung epithelial cells and that the T6SS protein Hcp is detected in the sputum of patients with CF. Altogether, these results suggest for the first time a role of T6SS in CF-lung colonization by A. xylosoxidans and opens promising perspective to target this virulence determinant as innovative theranostic options for CF management.
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Affiliation(s)
- Mélanie Le Goff
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), Aix-Marseille Université - Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 7255, Marseille, France
| | - Manon Vastel
- Université de Limoges, INSERM, Centre Hospitalier Universitaire (CHU) Limoges, Unité Mixte de Recherche (UMR) 1092, Limoges, France
| | - Régine Lebrun
- Plateforme Protéomique de l’Institut de Microbiologie de la Méditerranée, Marseille Protéomique, Aix Marseille Université, Centre National de la Recherche Scientifique (CNRS) FR 3479, Marseille, France
| | - Pascal Mansuelle
- Plateforme Protéomique de l’Institut de Microbiologie de la Méditerranée, Marseille Protéomique, Aix Marseille Université, Centre National de la Recherche Scientifique (CNRS) FR 3479, Marseille, France
| | - Ava Diarra
- Université de Lille, Centre National de la Recherche Scientifique (CNRS), INSERM, Centre Hospitalier Universitaire (CHU) Lille, Institut Pasteur de Lille, U1019-Unité Mixte de Recherche (UMR) 9017-CIIL-Centre d’Infection et d’Immunité de Lille, University of Lille, Lille, France
| | - Teddy Grandjean
- Université de Lille, Centre National de la Recherche Scientifique (CNRS), INSERM, Centre Hospitalier Universitaire (CHU) Lille, Institut Pasteur de Lille, U1019-Unité Mixte de Recherche (UMR) 9017-CIIL-Centre d’Infection et d’Immunité de Lille, University of Lille, Lille, France
| | - Pauline Triponney
- Centre National de Référence de la Résistance aux Antibiotiques , Centre Hospitalier Universitaire de Besançon, Besançon, France
| | | | - Philippe Gosset
- Université de Lille, Centre National de la Recherche Scientifique (CNRS), INSERM, Centre Hospitalier Universitaire (CHU) Lille, Institut Pasteur de Lille, U1019-Unité Mixte de Recherche (UMR) 9017-CIIL-Centre d’Infection et d’Immunité de Lille, University of Lille, Lille, France
| | - Rodrigue Dessein
- Université de Lille, Centre National de la Recherche Scientifique (CNRS), INSERM, Centre Hospitalier Universitaire (CHU) Lille, Institut Pasteur de Lille, U1019-Unité Mixte de Recherche (UMR) 9017-CIIL-Centre d’Infection et d’Immunité de Lille, University of Lille, Lille, France
| | - Fabien Garnier
- Université de Limoges, INSERM, Centre Hospitalier Universitaire (CHU) Limoges, Unité Mixte de Recherche (UMR) 1092, Limoges, France
- *Correspondence: Eric Durand, ; ; Fabien Garnier,
| | - Eric Durand
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), Aix-Marseille Université - Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 7255, Marseille, France
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), Aix-Marseille Université - Unité Mixte de Recherche (UMR) 7255, INSERM, Marseille, France
- *Correspondence: Eric Durand, ; ; Fabien Garnier,
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Identification of Antigenic Properties of Acinetobacter baumannii Proteins as Novel Putative Vaccine Candidates Using Reverse Vaccinology Approach. Appl Biochem Biotechnol 2022; 194:4892-4914. [PMID: 35670904 DOI: 10.1007/s12010-022-03995-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2022] [Indexed: 02/06/2023]
Abstract
Multidrug-resistant Acinetobacter baumannii (A. baumannii) infections are becoming more prevalent all over the world. As a cost-effective and preventative method, vaccination seems to be required against this bacterium. In the present study, subtractive proteomics along with reverse vaccinology approaches was used to predict suitable therapeutics against A. baumannii. Using the Vaxign online tool, we studied over 35 genomes of A. baumannii strains and chose outer membrane and secreted proteins of A. baumannii 1656-2 as possible vaccine candidates. Then, investigations were performed on the immunogenicity, antigenic characteristics, physicochemical properties, B-cell and MHC class I, and MHC class II molecules epitope densities of proteins. After optimizing the codon of the proteins, the pcDNA3.1( +) expression construct was designed and the immunogenicity, allergenicity, and physicochemical properties of the vaccine construct were predicted. Hcp and OmpC proteins were predicted as extracellular and outer membrane proteins, respectively. These proteins interact with 10 other proteins to form a network of protein interactions with virulence properties. Immunoassays of Hcp and OmpC proteins showed antigenicity of 0.88 and 0.79, respectively. These proteins have 5 structural cell epitope points and 5 linear B epitope points. They are also able to bind to different HLA alleles of MCH class I/class II as selected immunogenic proteins and designed non-allergenic structures with solubility of 0.650 and immunogenicity score of 0.91. The results of this "in silico" study indicate high specificity and the development of a significant humoral and cellular immune response. It can be concluded that the Hcp and OmpC dual vaccine construct is one of the promising candidates against A. baumannii. The findings of this "in silico" study show excellent specificity and the emergence of a substantial humoral and cellular immune response. This is a computer-based study that needs to be tested in vitro and in vivo to corroborate the conclusions of the vaccine design procedures.
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Boak EN, Kirolos S, Pan H, Pierson LS, Pierson EA. The Type VI Secretion Systems in Plant-Beneficial Bacteria Modulate Prokaryotic and Eukaryotic Interactions in the Rhizosphere. Front Microbiol 2022; 13:843092. [PMID: 35464916 PMCID: PMC9022076 DOI: 10.3389/fmicb.2022.843092] [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: 12/24/2021] [Accepted: 03/04/2022] [Indexed: 01/15/2023] Open
Abstract
Rhizosphere colonizing plant growth promoting bacteria (PGPB) increase their competitiveness by producing diffusible toxic secondary metabolites, which inhibit competitors and deter predators. Many PGPB also have one or more Type VI Secretion System (T6SS), for the delivery of weapons directly into prokaryotic and eukaryotic cells. Studied predominantly in human and plant pathogens as a virulence mechanism for the delivery of effector proteins, the function of T6SS for PGPB in the rhizosphere niche is poorly understood. We utilized a collection of Pseudomonas chlororaphis 30-84 mutants deficient in one or both of its two T6SS and/or secondary metabolite production to examine the relative importance of each T6SS in rhizosphere competence, bacterial competition, and protection from bacterivores. A mutant deficient in both T6SS was less persistent than wild type in the rhizosphere. Both T6SS contributed to competitiveness against other PGPB or plant pathogenic strains not affected by secondary metabolite production, but only T6SS-2 was effective against strains lacking their own T6SS. Having at least one T6SS was also essential for protection from predation by several eukaryotic bacterivores. In contrast to diffusible weapons that may not be produced at low cell density, T6SS afford rhizobacteria an additional, more immediate line of defense against competitors and predators.
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Affiliation(s)
- Emily N Boak
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
| | - Sara Kirolos
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Huiqiao Pan
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States.,Department of Embryology, Carnegie Institution for Science, Baltimore, MD, United States
| | - Leland S Pierson
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
| | - Elizabeth A Pierson
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States.,Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
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Liyanapathiranage P, Wagner N, Avram O, Pupko T, Potnis N. Phylogenetic Distribution and Evolution of Type VI Secretion System in the Genus Xanthomonas. Front Microbiol 2022; 13:840308. [PMID: 35495725 PMCID: PMC9048695 DOI: 10.3389/fmicb.2022.840308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/10/2022] [Indexed: 11/13/2022] Open
Abstract
The type VI secretion system (T6SS) present in many Gram-negative bacteria is a contact-dependent apparatus that can directly deliver secreted effectors or toxins into diverse neighboring cellular targets including both prokaryotic and eukaryotic organisms. Recent reverse genetics studies with T6 core gene loci have indicated the importance of functional T6SS toward overall competitive fitness in various pathogenic Xanthomonas spp. To understand the contribution of T6SS toward ecology and evolution of Xanthomonas spp., we explored the distribution of the three distinguishable T6SS clusters, i3*, i3***, and i4, in approximately 1,740 Xanthomonas genomes, along with their conservation, genetic organization, and their evolutionary patterns in this genus. Screening genomes for core genes of each T6 cluster indicated that 40% of the sequenced strains possess two T6 clusters, with combinations of i3*** and i3* or i3*** and i4. A few strains of Xanthomonas citri, Xanthomonas phaseoli, and Xanthomonas cissicola were the exception, possessing a unique combination of i3* and i4. The findings also indicated clade-specific distribution of T6SS clusters. Phylogenetic analysis demonstrated that T6SS clusters i3* and i3*** were probably acquired by the ancestor of the genus Xanthomonas, followed by gain or loss of individual clusters upon diversification into subsequent clades. T6 i4 cluster has been acquired in recent independent events by group 2 xanthomonads followed by its spread via horizontal dissemination across distinct clades across groups 1 and 2 xanthomonads. We also noted reshuffling of the entire core T6 loci, as well as T6SS spike complex components, hcp and vgrG, among different species. Our findings indicate that gain or loss events of specific T6SS clusters across Xanthomonas phylogeny have not been random.
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Affiliation(s)
| | - Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Oren Avram
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
- *Correspondence: Neha Potnis,
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Liyanapathiranage P, Jones JB, Potnis N. Mutation of a Single Core Gene, tssM, of Type VI Secretion System of Xanthomonas perforans Influences Virulence, Epiphytic Survival, and Transmission During Pathogenesis on Tomato. PHYTOPATHOLOGY 2022; 112:752-764. [PMID: 34543058 DOI: 10.1094/phyto-02-21-0069-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Xanthomonas perforans is a seedborne hemibiotrophic pathogen that successfully establishes infection in the phyllosphere of tomato. While most studies investigating mechanistic basis of pathogenesis have focused on successful apoplastic growth, factors important during asymptomatic colonization in the early stages of disease development are not well understood. In this study, we show that tssM gene of the type VI secretion system cluster i3* (T6SS-i3*) plays a significant role during initial asymptomatic epiphytic colonization at different stages during the life cycle of the pathogen. Mutation in a core gene, tssM of T6SS-i3*, imparted higher aggressiveness to the pathogen, as indicated by higher overall disease severity, higher in planta growth, and shorter latent infection period compared with the wild-type upon dip inoculation of 4- to 5-week-old tomato plants. Contribution of tssM toward aggressiveness was evident during vertical transmission from seed to seedling, with wild-type showing reduced disease severity as well as lower in planta populations on seedlings compared with the mutant. Presence of functional TssM offered higher epiphytic fitness as well as higher dissemination potential to the pathogen when tested in an experimental setup mimicking transplant house high-humidity conditions. We showed higher osmotolerance being one mechanism by which TssM offers higher epiphytic fitness. Taken together, these data reveal that functional TssM plays a larger role in offering ecological advantage to the pathogen. TssM prolongs the association of hemibiotrophic pathogen with the host, minimizing overall disease severity yet facilitating successful dissemination.
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Affiliation(s)
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849
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Development of Multiplex PCR Assay for Screening of T6SS-5 Gene Cluster: The Burkholderia pseudomallei Virulence Factor. Diagnostics (Basel) 2022; 12:diagnostics12030562. [PMID: 35328115 PMCID: PMC8947302 DOI: 10.3390/diagnostics12030562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/14/2022] [Accepted: 02/21/2022] [Indexed: 11/17/2022] Open
Abstract
Despite the advanced understanding of the disease, melioidosis, an infection caused by Burkholderia pseudomallei, continues to be of global interest. The bacterial virulence factor, type six secretion system-5 (T6SS-5), in particular, is an essential factor for B. pseudomallei that is associated with internalization and intracellular survival of the pathogen. To detect the virulence gene cluster, this study has successfully developed a novel seven-gene (tssC-5, tagD-5, tssA-5, hcp-5, tssB-5, tssF-5, and vgrG-5) multiplex PCR assay. The optimum annealing temperature for this assay ranged between 59 and 62 °C. The limit of detection for this assay was 103 CFU/mL for all genes, excluding tssF-5, which was found at 105 CFU/mL of the bacterial concentration. In sensitivity and specificity tests, this multiplex assay was able to amplify all of the seven target genes from 93.8% (n = 33/35) clinical and 100% (n = 2/2) environmental isolates of B. pseudomallei. Whereas only four genes (tssC-5, tagD-5, tssF-5, and vgrG-5) were amplified from Bukholderia thailandesis, two genes (tagD-5 and tssB-5) were amplified from Bukholderia stagnalis, and zero target genes were amplified from Bukholderia ubonensis. No amplification of any genes was obtained when tested against isolated DNA from non-Bukholderia species (n = 20), which include Staphylococcus aureus, Klebsiella pneumoniae, Enterococcus faecalis, and others. In conclusion, this multiplex PCR assay is sensitive, species-specific, rapid, and reliable to detect the virulent gene cluster T6SS-5 of B. pseudomallei.
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Amaya FA, Blondel CJ, Barros-Infante MF, Rivera D, Moreno-Switt AI, Santiviago CA, Pezoa D. Identification of Type VI Secretion Systems Effector Proteins That Contribute to Interbacterial Competition in Salmonella Dublin. Front Microbiol 2022; 13:811932. [PMID: 35222335 PMCID: PMC8867033 DOI: 10.3389/fmicb.2022.811932] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/04/2022] [Indexed: 12/12/2022] Open
Abstract
The Type VI Secretion System (T6SS) is a multiprotein device that has emerged as an important fitness and virulence factor for many Gram-negative bacteria through the injection of effector proteins into prokaryotic or eukaryotic cells via a contractile mechanism. While some effector proteins specifically target bacterial or eukaryotic cells, others can target both types of cells (trans-kingdom effectors). In Salmonella, five T6SS gene clusters have been identified within pathogenicity islands SPI-6, SPI-19, SPI-20, SPI-21, and SPI-22, which are differentially distributed among serotypes. Salmonella enterica serotype Dublin (S. Dublin) is a cattle-adapted pathogen that harbors both T6SSSPI-6 and T6SSSPI-19. Interestingly, while both systems have been linked to virulence and host colonization in S. Dublin, an antibacterial activity has not been detected for T6SSSPI-6 in this serotype. In addition, there is limited information regarding the repertoire of effector proteins encoded within T6SSSPI-6 and T6SSSPI-19 gene clusters in S. Dublin. In the present study, we demonstrate that T6SSSPI-6 and T6SSSPI-19 of S. Dublin CT_02021853 contribute to interbacterial competition. Bioinformatic and comparative genomic analyses allowed us to identify genes encoding three candidate antibacterial effectors located within SPI-6 and two candidate effectors located within SPI-19. Each antibacterial effector gene is located upstream of a gene encoding a hypothetic immunity protein, thus conforming an effector/immunity (E/I) module. Of note, the genes encoding these effectors and immunity proteins are widely distributed in Salmonella genomes, suggesting a relevant role in interbacterial competition and virulence. Finally, we demonstrate that E/I modules SED_RS01930/SED_RS01935 (encoded in SPI-6), SED_RS06235/SED_RS06230, and SED_RS06335/SED_RS06340 (both encoded in SPI-19) contribute to interbacterial competition in S. Dublin CT_02021853.
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Affiliation(s)
- Fernando A. Amaya
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Carlos J. Blondel
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | | | - Dácil Rivera
- Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Andrea I. Moreno-Switt
- Escuela de Medicina Veterinaria, Facultad de Agronomía e Ingeniería Forestal, Facultad de Ciencias Biológicas y Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millennium Initiative on Collaborative Research on Bacterial Resistance (MICROB-R), Santiago, Chile
| | - Carlos A. Santiviago
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
- *Correspondence: Carlos A. Santiviago, David Pezoa,
| | - David Pezoa
- Escuela de Medicina Veterinaria, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- *Correspondence: Carlos A. Santiviago, David Pezoa,
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Allen ME, Albon J, Elani Y. Layer-by-layer assembly of multi-layered droplet interface bilayers (multi-DIBs). Chem Commun (Camb) 2021; 58:60-63. [PMID: 34877578 DOI: 10.1039/d1cc05155e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Droplet interface bilayers (DIBs) have tremendous promise as platforms for fundamental biomembrane studies and in biotechnology. Being composed of a single bilayer however limits their biomimetic potential, as many cell membrane motifs are composed of multiple aligned bilayers. We describe a technology to manufacture cell-sized multi-layered DIBs (multi-DIBs) by coating giant unilamellar vesicles with a further monolayer, and allowing such structures to make contact with themselves or a monolayer coated droplet. This easily customisable strategy will pave the way for an expanded repertoire of DIB functionality, for example by facilitating the incorporation of multiple-bilayer spanning protein complexes.
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Affiliation(s)
- Matthew E Allen
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub White City, London, W12 0BZ, UK.,Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London, W12 0BZ, UK. .,Department of Chemical Engineering, Imperial College London South Kensington, London, SW7 2AZ, UK
| | - James Albon
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub White City, London, W12 0BZ, UK
| | - Yuval Elani
- Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London, W12 0BZ, UK. .,Department of Chemical Engineering, Imperial College London South Kensington, London, SW7 2AZ, UK
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Mounting, structure and autocleavage of a type VI secretion-associated Rhs polymorphic toxin. Nat Commun 2021; 12:6998. [PMID: 34853317 PMCID: PMC8636562 DOI: 10.1038/s41467-021-27388-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/15/2021] [Indexed: 12/30/2022] Open
Abstract
Bacteria have evolved toxins to outcompete other bacteria or to hijack host cell pathways. One broad family of bacterial polymorphic toxins gathers multidomain proteins with a modular organization, comprising a C-terminal toxin domain fused to a N-terminal domain that adapts to the delivery apparatus. Polymorphic toxins include bacteriocins, contact-dependent growth inhibition systems, and specialized Hcp, VgrG, PAAR or Rhs Type VI secretion (T6SS) components. We recently described and characterized Tre23, a toxin domain fused to a T6SS-associated Rhs protein in Photorhabdus laumondii, Rhs1. Here, we show that Rhs1 forms a complex with the T6SS spike protein VgrG and the EagR chaperone. Using truncation derivatives and cross-linking mass spectrometry, we demonstrate that VgrG-EagR-Rhs1 complex formation requires the VgrG C-terminal β-helix and the Rhs1 N-terminal region. We then report the cryo-electron-microscopy structure of the Rhs1-EagR complex, demonstrating that the Rhs1 central region forms a β-barrel cage-like structure that encapsulates the C-terminal toxin domain, and provide evidence for processing of the Rhs1 protein through aspartyl autoproteolysis. We propose a model for Rhs1 loading on the T6SS, transport and delivery into the target cell.
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Quantification and surface localization of the hemolysin A type 1 secretion system at the endogenous level and under conditions of overexpression. Appl Environ Microbiol 2021; 88:e0189621. [PMID: 34851699 DOI: 10.1128/aem.01896-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Secretion systems are essential for Gram-negative bacteria as these nanomachineries allow a communication with the outside world by exporting proteins into the extracellular space or directly into the cytosol of a host cell. For example, type one secretion systems (T1SS) secrete a broad range of substrates across both membranes into the extracellular space. One well-known example is the hemolysin A (HlyA) T1SS from Escherichia coli (E. coli), which consists of an ABC transporter (HlyB), a membrane fusion protein (HlyD), the outer membrane protein TolC and the substrate HlyA, a member of the family of RTX (repeats in toxins) toxins. Here, we determined the amount of TolC at the endogenous level (parental strain, UTI89) and under conditions of overexpression (T7 expression system, BL21(DE3)-BD). The overall amount of TolC was not influenced by the overexpression of the HlyBD complex. Moving one step further, we determined the localization of the HlyA T1SS by super-resolution microscopy. In contrast to other bacterial secretion systems, no polarization was observed with respect to endogenous or overexpression levels. Additionally, the cell growth and division cycle did not influence the polarization. Most importantly, the size of the observed T1SS clusters did not correlate with the recently proposed outer membrane islands. These data indicate that T1SS cluster at the outer membrane generating domains of so far not described identity. Importance Uropathogenic Escherichia coli (UPEC) strains cause about 110 million urinary tract infections each year worldwide representing a global burden to the healthcare system. UPEC secrete many virulence factors among these the TX toxin hemolysin A via a cognate T1SS into the extracellular space. In this study, we determined the endogenous copy number of the HlyA T1SS in UTI89 and analyzed the surface localization in BL21(DE3)-BD and UTI89, respectively. With approximately 800 copies of the T1SS in UTI89, this is one of the highest expressed bacterial secretion systems. Furthermore and in clear contrast to other secretion systems, no polarized surface localization was detected. Finally, quantitative analysis of the super-resolution data revealed that clusters of the HlyA T1SS are not related to the recently identified outer membrane protein islands. These data provide insights into the quantitative molecular architecture of the HlyA T1SS.
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ClpV1 in avian pathogenic Escherichia coli is a crucial virulence factor contributing to meningitis in a mouse model in vivo. Vet Microbiol 2021; 263:109273. [PMID: 34763144 DOI: 10.1016/j.vetmic.2021.109273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 10/29/2021] [Indexed: 11/22/2022]
Abstract
Meningitis associated with avian pathogenic Escherichia coli (APEC) is an infectious disease of poultry that has gained significant attention because of its potential to infect humans. APEC can utilize two type Ⅵ secretion systems (T6SSs) to efficiently transport toxin effectors into hosts. ClpV1 is one of the core components of the T6SS1. To our knowledge, it has not been clarified how the clpV1 gene contributes to the pathogenicity of meningitis-associated APEC. To investigate the function of the clpV1 gene in the process of Escherichia coli meningitis, a mutant TW-XMΔclpV1 strain was constructed and characterized. In this study, the clpV1 deleted strain displayed a significant decrease in both motility and biofilm formation as well as a reduction in the expression of virulence genes fliC, luxS and ibeA. In vivo studies using mouse and duck models found that the clpV1 deleted groups showed decreased proliferation, fewer lesions and lower expression of inflammatory cytokines in the brain suggesting that clpV1 is involved in the pathogenicity of TWXM. Besides, the decreased quantity of Evans Blue (EB) and the down-regulation of tight junctions (TJs) proteins in the mouse clpV1 deleted group demonstrating a more intact blood-brain barrier (BBB). In conclusion, these results suggest that the clpV1 gene is associated with motility and biofilm formation of TWXM strain and contributes to meningitis by damaging the BBB and brain tissues.
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Cassan FD, Coniglio A, Amavizca E, Maroniche G, Cascales E, Bashan Y, de-Bashan LE. The Azospirillum brasilense type VI secretion system promotes cell aggregation, biocontrol protection against phytopathogens and attachment to the microalgae Chlorella sorokiniana. Environ Microbiol 2021; 23:6257-6274. [PMID: 34472164 DOI: 10.1111/1462-2920.15749] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/25/2021] [Accepted: 08/28/2021] [Indexed: 01/26/2023]
Abstract
The plant-growth-promoting bacterium Azospirillum brasilense is able to associate with the microalgae Chlorella sorokiniana. Attachment of A. brasilense increases the metabolic performances of the microalgae. Recent genome analyses have revealed that the A. brasilense Az39 genome contains two complete sets of genes encoding type VI secretion systems (T6SS), including the T6SS1 that is induced by the indole-3-acetic acid (IAA) phytohormone. The T6SS is a multiprotein machine, widespread in Gram-negative bacteria, that delivers protein effectors in both prokaryotic and eukaryotic cells. Here we show that the A. brasilense T6SS is required for Chlorella-Azospirillum synthetic mutualism. Our data demonstrate that the T6SS is an important determinant to promote production of lipids, carbohydrates and photosynthetic pigments by the microalgae. We further show that this is likely due to the role of the T6SS during the attachment stage and for the production of IAA phytohormones. Finally, we demonstrate that the A. brasilense T6SS provides antagonistic activities against a number of plant pathogens such as Agrobacterium, Pectobacterium, Dickeya and Ralstonia species in vitro, suggesting that, in addition to promoting growth, A. brasilense might confer T6SS-dependent bio-control protection to microalgae and plants against bacterial pathogens.
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Affiliation(s)
- Fabricio D Cassan
- Laboratorio de Fisiología Vegetal y de la interacción Planta-Microorganismo, Instituto de Investigaciones Agrobiotecnológicas (INIAB), Universidad Nacional de Río Cuarto, Córdoba, Argentina
| | - Anahí Coniglio
- Laboratorio de Fisiología Vegetal y de la interacción Planta-Microorganismo, Instituto de Investigaciones Agrobiotecnológicas (INIAB), Universidad Nacional de Río Cuarto, Córdoba, Argentina
| | - Edgar Amavizca
- Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), La Paz, Mexico
| | - Guillermo Maroniche
- Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata, Buenos Aires, Argentina
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université - CNRS UMR7255, Marseille, France
| | - Yoav Bashan
- Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), La Paz, Mexico.,The Bashan Institute of Science, Auburn, AL, USA
| | - Luz E de-Bashan
- Environmental Microbiology Group, Northwestern Center for Biological Research (CIBNOR), La Paz, Mexico.,The Bashan Institute of Science, Auburn, AL, USA.,Department of Entomology and Plant Pathology, 301 Funchess Hall, Auburn University, Auburn, AL, USA
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44
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Cameranesi MM, Kurth D, Repizo GD. Acinetobacter defence mechanisms against biological aggressors and their use as alternative therapeutic applications. Crit Rev Microbiol 2021; 48:21-41. [PMID: 34289313 DOI: 10.1080/1040841x.2021.1939266] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Several Acinetobacter strains are important nosocomial pathogens, with Acinetobacter baumannii being the species of greatest worldwide concern due to its multi-drug resistance and the recent appearance of hyper-virulent strains in the clinical setting. Colonisation of this environment is associated with a multitude of bacterial factors, and the molecular features that promote environmental persistence in abiotic surfaces, including intrinsic desiccation resistance, biofilm formation and motility, have been previously addressed. On the contrary, mechanisms enabling Acinetobacter spp. survival when faced against other biological competitors are starting to be characterised. Among them, secretion systems (SS) of different types, such as the T5bSS (Contact-dependent inhibition systems) and the T6SS, confer adaptive advantages against bacterial aggressors. Regarding mechanisms of defence against bacteriophages, such as toxin-antitoxin, restriction-modification, Crispr-Cas and CBASS, among others, have been identified but remain poorly characterised. In view of this, we aimed to summarise the present knowledge on defence mechanisms that enable niche establishment in members of the Acinetobacter genus. Different proposals are also described for the use of some components of these systems as molecular tools to treat Acinetobacter infections.
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Affiliation(s)
- María Marcela Cameranesi
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Daniel Kurth
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI, CONICET), San Miguel de Tucumán, Argentina
| | - Guillermo Daniel Repizo
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
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45
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Jurėnas D, Payelleville A, Roghanian M, Turnbull KJ, Givaudan A, Brillard J, Hauryliuk V, Cascales E. Photorhabdus antibacterial Rhs polymorphic toxin inhibits translation through ADP-ribosylation of 23S ribosomal RNA. Nucleic Acids Res 2021; 49:8384-8395. [PMID: 34255843 PMCID: PMC8661411 DOI: 10.1093/nar/gkab608] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/10/2021] [Accepted: 07/01/2021] [Indexed: 11/18/2022] Open
Abstract
Bacteria have evolved sophisticated mechanisms to deliver potent toxins into bacterial competitors or into eukaryotic cells in order to destroy rivals and gain access to a specific niche or to hijack essential metabolic or signaling pathways in the host. Delivered effectors carry various activities such as nucleases, phospholipases, peptidoglycan hydrolases, enzymes that deplete the pools of NADH or ATP, compromise the cell division machinery, or the host cell cytoskeleton. Effectors categorized in the family of polymorphic toxins have a modular structure, in which the toxin domain is fused to additional elements acting as cargo to adapt the effector to a specific secretion machinery. Here we show that Photorhabdus laumondii, an entomopathogen species, delivers a polymorphic antibacterial toxin via a type VI secretion system. This toxin inhibits protein synthesis in a NAD+-dependent manner. Using a biotinylated derivative of NAD, we demonstrate that translation is inhibited through ADP-ribosylation of the ribosomal 23S RNA. Mapping of the modification further showed that the adduct locates on helix 44 of the thiostrepton loop located in the GTPase-associated center and decreases the GTPase activity of the EF-G elongation factor.
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Affiliation(s)
- Dukas Jurėnas
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), Aix-Marseille Université - CNRS, UMR 7255, Marseille, France
| | - Amaury Payelleville
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), Aix-Marseille Université - CNRS, UMR 7255, Marseille, France.,DGIMI, Univ Montpellier, INRAE, Montpellier, France
| | - Mohammad Roghanian
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden, Umeå University, 901 87 Umeå, Sweden
| | | | | | | | - Vasili Hauryliuk
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden, Umeå University, 901 87 Umeå, Sweden.,Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden.,University of Tartu, Institute of Technology, 50411 Tartu, Estonia
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), Aix-Marseille Université - CNRS, UMR 7255, Marseille, France
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46
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Nguyen VS, Spinelli S, Cascales É, Roussel A, Cambillau C, Leone P. Anchoring the T6SS to the cell wall: Crystal structure of the peptidoglycan binding domain of the TagL accessory protein. PLoS One 2021; 16:e0254232. [PMID: 34214145 PMCID: PMC8253398 DOI: 10.1371/journal.pone.0254232] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/22/2021] [Indexed: 11/22/2022] Open
Abstract
The type VI secretion system (T6SS) is a widespread mechanism of protein delivery into target cells, present in more than a quarter of all sequenced Gram-negative bacteria. The T6SS constitutes an important virulence factor, as it is responsible for targeting effectors in both prokaryotic and eukaryotic cells. The T6SS comprises a tail structure tethered to the cell envelope via a trans-envelope complex. In most T6SS, the membrane complex is anchored to the cell wall by the TagL accessory protein. In this study, we report the first crystal structure of a peptidoglycan-binding domain of TagL. The fold is conserved with members of the OmpA/Pal/MotB family, and more importantly, the peptidoglycan binding site is conserved. This structure further exemplifies how proteins involved in anchoring to the cell wall for different cellular functions rely on an interaction network with peptidoglycan strictly conserved.
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Affiliation(s)
- Van Son Nguyen
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Marseille, France
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique (UMR7257), Marseille, France
| | - Silvia Spinelli
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Marseille, France
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique (UMR7257), Marseille, France
| | - Éric Cascales
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, Centre National de la Recherche Scientifique (UMR7255), Aix-Marseille Université, Marseille, France
| | - Alain Roussel
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Marseille, France
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique (UMR7257), Marseille, France
| | - Christian Cambillau
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Marseille, France
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique (UMR7257), Marseille, France
| | - Philippe Leone
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Marseille, France
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique (UMR7257), Marseille, France
- * E-mail:
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47
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Robinson L, Liaw J, Omole Z, Xia D, van Vliet AHM, Corcionivoschi N, Hachani A, Gundogdu O. Bioinformatic Analysis of the Campylobacter jejuni Type VI Secretion System and Effector Prediction. Front Microbiol 2021; 12:694824. [PMID: 34276628 PMCID: PMC8285248 DOI: 10.3389/fmicb.2021.694824] [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: 04/13/2021] [Accepted: 06/07/2021] [Indexed: 12/30/2022] Open
Abstract
The Type VI Secretion System (T6SS) has important roles relating to bacterial antagonism, subversion of host cells, and niche colonisation. Campylobacter jejuni is one of the leading bacterial causes of human gastroenteritis worldwide and is a commensal coloniser of birds. Although recently discovered, the T6SS biological functions and identities of its effectors are still poorly defined in C. jejuni. Here, we perform a comprehensive bioinformatic analysis of the C. jejuni T6SS by investigating the prevalence and genetic architecture of the T6SS in 513 publicly available genomes using C. jejuni 488 strain as reference. A unique and conserved T6SS cluster associated with the Campylobacter jejuni Integrated Element 3 (CJIE3) was identified in the genomes of 117 strains. Analyses of the T6SS-positive 488 strain against the T6SS-negative C. jejuni RM1221 strain and the T6SS-positive plasmid pCJDM202 carried by C. jejuni WP2-202 strain defined the “T6SS-containing CJIE3” as a pathogenicity island, thus renamed as Campylobacter jejuni Pathogenicity Island-1 (CJPI-1). Analysis of CJPI-1 revealed two canonical VgrG homologues, CJ488_0978 and CJ488_0998, harbouring distinct C-termini in a genetically variable region downstream of the T6SS operon. CJPI-1 was also found to carry a putative DinJ-YafQ Type II toxin-antitoxin (TA) module, conserved across pCJDM202 and the genomic island CJIE3, as well as several open reading frames functionally predicted to encode for nucleases, lipases, and peptidoglycan hydrolases. This comprehensive in silico study provides a framework for experimental characterisation of T6SS-related effectors and TA modules in C. jejuni.
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Affiliation(s)
- Luca Robinson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Janie Liaw
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Zahra Omole
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Dong Xia
- Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Arnoud H M van Vliet
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Nicolae Corcionivoschi
- Bacteriology Branch, Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, United Kingdom.,Bioengineering of Animal Science Resources, Banat University of Agricultural Sciences and Veterinary Medicine - King Michael the I of Romania, Timisoara, Romania
| | - Abderrahman Hachani
- The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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48
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Rosenzweig JA, Hendrix EK, Chopra AK. Plague vaccines: new developments in an ongoing search. Appl Microbiol Biotechnol 2021; 105:4931-4941. [PMID: 34142207 PMCID: PMC8211537 DOI: 10.1007/s00253-021-11389-6] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/25/2021] [Accepted: 06/02/2021] [Indexed: 11/17/2022]
Abstract
As the reality of pandemic threats challenges humanity, exemplified during the ongoing SARS-CoV-2 infections, the development of vaccines targeting these etiological agents of disease has become increasingly critical. Of paramount concern are novel and reemerging pathogens that could trigger such events, including the plague bacterium Yersinia pestis. Y. pestis is responsible for more human deaths than any other known pathogen and exists globally in endemic regions of the world, including the four corners region and Northern California in the USA. Recent cases have been scattered throughout the world, including China and the USA, with serious outbreaks in Madagascar during 2008, 2013-2014, and, most recently, 2017-2018. This review will focus on recent advances in plague vaccine development, a seemingly necessary endeavor, as there is no Food and Drug Administration-licensed vaccine available for human distribution in western nations, and that antibiotic-resistant strains are recovered clinically or intentionally developed. Progress and recent development involving subunit, live-attenuated, and nucleic acid-based plague vaccine candidates will be discussed in this review. KEY POINTS: • Plague vaccine development remains elusive yet critical. • DNA, animal, and live-attenuated vaccine candidates gain traction.
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Affiliation(s)
- Jason A Rosenzweig
- Department of Biology, Texas Southern University, Houston, TX, 77004, USA.
| | - Emily K Hendrix
- Departmnet of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Ashok K Chopra
- Departmnet of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
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49
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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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50
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Evolution of Interbacterial Antagonism in Bee Gut Microbiota Reflects Host and Symbiont Diversification. mSystems 2021; 6:6/3/e00063-21. [PMID: 33975963 PMCID: PMC8125069 DOI: 10.1128/msystems.00063-21] [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] [Indexed: 11/20/2022] Open
Abstract
Antagonistic interactions between bacteria affect diversity and dynamics of host-associated communities, including gut communities that are linked to host health. In many bacterial communities, including human and honey bee gut microbiotas, antagonism is mediated by type VI secretion systems (T6SSs) that deliver lethal toxins to competing strains. Gram-negative bacteria frequently possess type VI secretion systems (T6SSs), protein complexes that are able to inject toxic proteins into nearby cells. Many aspects of T6SS structure and function have been characterized for model species, but less is known about the evolutionary processes that shape T6SS and effector (toxin) diversity in host-associated microbial communities. The bee gut microbiota is a simple community that has codiversified with bees for >80 million years. This study investigated how complements of T6SSs and effectors within the bee microbiota changed as bacteria and their hosts diversified into isolated species. We used protein homology to survey 198 isolate genomes of 9 Gram-negative species for genes encoding T6SS structural components; Rhs toxins, which are common T6SS effectors; and VgrG proteins, which are structural components associated with specific toxins. T6SS loci were present in 5 species clusters found only in bees, namely Apibacter spp., Gilliamella spp., Frischella perrara, “Candidatus Schmidhempelia bombi,” and Snodgrassella alvi. The distribution of T6SS loci suggests that at least 3 were present in the microbiota of the common ancestor of social bees and that loss of these genes in some bacterial lineages was linked to both host and bacterial speciation. Isolates differed enormously in repertoires of Rhs and VgrG proteins. We found that bacterial species employ different mechanisms for toxin acquisition and diversification and that species and strains sometimes lose the T6SS entirely, likely causing shifts in competitive dynamics within these communities. IMPORTANCE Antagonistic interactions between bacteria affect diversity and dynamics of host-associated communities, including gut communities that are linked to host health. In many bacterial communities, including human and honey bee gut microbiotas, antagonism is mediated by type VI secretion systems (T6SSs) that deliver lethal toxins to competing strains. In this study, we explored how T6SSs and associated toxins have evolved in the simple, host-specific gut microbiota of honey bees and bumble bees. Using comparative genomics, we explored the conservation, recombination, horizontal transfer, and loss of T6SSs and effectors during 80 million years of evolution of this bee-associated community. We find that that patterns of T6SS loss and retention are linked to differences in biology across host species, while trends in effector diversification are mostly specific to bacterial lineages.
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