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Sonani RR, Esteves NC, Scharf BE, Egelman EH. Cryo-EM structure of flagellotropic bacteriophage Chi. Structure 2024; 32:856-865.e3. [PMID: 38614087 PMCID: PMC11246221 DOI: 10.1016/j.str.2024.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 02/08/2024] [Accepted: 03/19/2024] [Indexed: 04/15/2024]
Abstract
The flagellotropic bacteriophage χ (Chi) infects bacteria via the flagellar filament. Despite years of study, its structural architecture remains partly characterized. Through cryo-EM, we unveil χ's nearly complete structure, encompassing capsid, neck, tail, and tail tip. While the capsid and tail resemble phage YSD1, the neck and tail tip reveal new proteins and their arrangement. The neck shows a unique conformation of the tail tube protein, forming a socket-like structure for attachment to the neck. The tail tip comprises four proteins, including distal tail protein (DTP), two baseplate hub proteins (BH1P and BH2P), and tail tip assembly protein (TAP) exhibiting minimal organization compared to other siphophages. Deviating from the consensus in other siphophages, DTP in χ forms a trimeric assembly, reducing tail symmetry from 6-fold to 3-fold at the tip. These findings illuminate the previously unexplored structural organization of χ's neck and tail tip.
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Affiliation(s)
- Ravi R Sonani
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | | | - Birgit E Scharf
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA.
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2
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Nang SC, Lu J, Yu HH, Wickremasinghe H, Azad MAK, Han M, Zhao J, Rao G, Bergen PJ, Velkov T, Sherry N, McCarthy DT, Aslam S, Schooley RT, Howden BP, Barr JJ, Zhu Y, Li J. Phage resistance in Klebsiella pneumoniae and bidirectional effects impacting antibiotic susceptibility. Clin Microbiol Infect 2024; 30:787-794. [PMID: 38522841 DOI: 10.1016/j.cmi.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/11/2024] [Accepted: 03/14/2024] [Indexed: 03/26/2024]
Abstract
OBJECTIVES Bacteriophage (phage) therapy is a promising anti-infective option to combat antimicrobial resistance. However, the clinical utilization of phage therapy has been severely compromised by the potential emergence of phage resistance. Although certain phage resistance mechanisms can restore bacterial susceptibility to certain antibiotics, a lack of knowledge of phage resistance mechanisms hinders optimal use of phages and their combination with antibiotics. METHODS Genome-wide transposon screening was performed with a mutant library of Klebsiella pneumoniae MKP103 to identify phage pKMKP103_1-resistant mutants. Phage-resistant phenotypes were evaluated by time-kill kinetics and efficiency of plating assays. Phage resistance mechanisms were investigated with adsorption, one-step growth, and mutation frequency assays. Antibiotic susceptibility was determined with broth microdilution and population analysis profiles. RESULTS We observed a repertoire of phage resistance mechanisms in K pneumoniae, such as disruption of phage binding (fhuA::Tn and tonB::Tn), extension of the phage latent period (mnmE::Tn and rpoN::Tn), and increased mutation frequency (mutS::Tn and mutL::Tn). Notably, in contrast to the prevailing view that phage resistance re-sensitizes antibiotic-resistant bacteria, we observed a bidirectional steering effect on bacterial antibiotic susceptibility. Specifically, rpoN::Tn increased susceptibility to colistin while mutS::Tn and mutL::Tn increased resistance to rifampicin and colistin. DISCUSSION Our findings demonstrate that K pneumoniae employs multiple strategies to overcome phage infection, which may result in enhanced or reduced antibiotic susceptibility. Mechanism-guided phage steering should be incorporated into phage therapy to better inform clinical decisions on phage-antibiotic combinations.
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Affiliation(s)
- Sue C Nang
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Jing Lu
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Heidi H Yu
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Hasini Wickremasinghe
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Mohammad A K Azad
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Meiling Han
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Jinxin Zhao
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Gauri Rao
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA
| | - Phillip J Bergen
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Tony Velkov
- Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Norelle Sherry
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - David T McCarthy
- Department of Civil Engineering, Monash University, Clayton, Victoria, Australia
| | - Saima Aslam
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Robert T Schooley
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Benjamin P Howden
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Jeremy J Barr
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Yan Zhu
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Jian Li
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
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3
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Eigenfeld M, Lupp KFM, Schwaminger SP. Role of Natural Binding Proteins in Therapy and Diagnostics. Life (Basel) 2024; 14:630. [PMID: 38792650 PMCID: PMC11122601 DOI: 10.3390/life14050630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/02/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
This review systematically investigates the critical role of natural binding proteins (NBPs), encompassing DNA-, RNA-, carbohydrate-, fatty acid-, and chitin-binding proteins, in the realms of oncology and diagnostics. In an era where cancer continues to pose significant challenges to healthcare systems worldwide, the innovative exploration of NBPs offers a promising frontier for advancing both the diagnostic accuracy and therapeutic efficacy of cancer management strategies. This manuscript provides an in-depth examination of the unique mechanisms by which NBPs interact with specific molecular targets, highlighting their potential to revolutionize cancer diagnostics and therapy. Furthermore, it discusses the burgeoning research on aptamers, demonstrating their utility as 'nucleic acid antibodies' for targeted therapy and precision diagnostics. Despite the promising applications of NBPs and aptamers in enhancing early cancer detection and developing personalized treatment protocols, this review identifies a critical knowledge gap: the need for comprehensive studies to understand the diverse functionalities and therapeutic potentials of NBPs across different cancer types and diagnostic scenarios. By bridging this gap, this manuscript underscores the importance of NBPs and aptamers in paving the way for next-generation diagnostics and targeted cancer treatments.
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Affiliation(s)
- Marco Eigenfeld
- Otto-Loewi Research Center, Division of Medicinal Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
| | - Kilian F. M. Lupp
- Otto-Loewi Research Center, Division of Medicinal Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
| | - Sebastian P. Schwaminger
- Otto-Loewi Research Center, Division of Medicinal Chemistry, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
- BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
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4
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Dicks LMT, Vermeulen W. Bacteriophage-Host Interactions and the Therapeutic Potential of Bacteriophages. Viruses 2024; 16:478. [PMID: 38543843 PMCID: PMC10975011 DOI: 10.3390/v16030478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 05/23/2024] Open
Abstract
Healthcare faces a major problem with the increased emergence of antimicrobial resistance due to over-prescribing antibiotics. Bacteriophages may provide a solution to the treatment of bacterial infections given their specificity. Enzymes such as endolysins, exolysins, endopeptidases, endosialidases, and depolymerases produced by phages interact with bacterial surfaces, cell wall components, and exopolysaccharides, and may even destroy biofilms. Enzymatic cleavage of the host cell envelope components exposes specific receptors required for phage adhesion. Gram-positive bacteria are susceptible to phage infiltration through their peptidoglycan, cell wall teichoic acid (WTA), lipoteichoic acids (LTAs), and flagella. In Gram-negative bacteria, lipopolysaccharides (LPSs), pili, and capsules serve as targets. Defense mechanisms used by bacteria differ and include physical barriers (e.g., capsules) or endogenous mechanisms such as clustered regularly interspaced palindromic repeat (CRISPR)-associated protein (Cas) systems. Phage proteins stimulate immune responses against specific pathogens and improve antibiotic susceptibility. This review discusses the attachment of phages to bacterial cells, the penetration of bacterial cells, the use of phages in the treatment of bacterial infections, and the limitations of phage therapy. The therapeutic potential of phage-derived proteins and the impact that genomically engineered phages may have in the treatment of infections are summarized.
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Affiliation(s)
- Leon M. T. Dicks
- Department of Microbiology, Stellenbosch University, Stellenbosch 7600, South Africa;
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5
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Ouyang R, Ongenae V, Muok A, Claessen D, Briegel A. Phage fibers and spikes: a nanoscale Swiss army knife for host infection. Curr Opin Microbiol 2024; 77:102429. [PMID: 38277900 DOI: 10.1016/j.mib.2024.102429] [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: 09/06/2023] [Revised: 12/19/2023] [Accepted: 01/08/2024] [Indexed: 01/28/2024]
Abstract
Bacteriophages are being rediscovered as potent agents for medical and industrial applications. However, finding a suitable phage relies on numerous factors, including host specificity, burst size, and infection cycle. The host range of a phage is, besides phage defense systems, initially determined by the recognition and attachment of receptor-binding proteins (RBPs) to the target receptors of susceptible bacteria. RBPs include tail (or occasionally head) fibers and tailspikes. Owing to the potential flexibility and heterogeneity of these structures, they are often overlooked during structural studies. Recent advances in cryo-electron microscopy studies and computational approaches have begun to unravel their structural and fundamental mechanisms during phage infection. In this review, we discuss the current state of research on different phage tail and head fibers, spike models, and molecular mechanisms. These details may facilitate the manipulation of phage-host specificity, which in turn will have important implications for science and society.
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Affiliation(s)
- Ruochen Ouyang
- Department of Microbial Sciences, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xianning West Road 28, Xi'an 710049, China
| | - Véronique Ongenae
- Department of Microbial Sciences, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Alise Muok
- Department of Microbial Sciences, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands
| | - Dennis Claessen
- Department of Microbial Sciences, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Ariane Briegel
- Department of Microbial Sciences, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands.
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6
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Sonani RR, Palmer LK, Esteves NC, Horton AA, Sebastian AL, Kelly RJ, Wang F, Kreutzberger MAB, Russell WK, Leiman PG, Scharf BE, Egelman EH. An extensive disulfide bond network prevents tail contraction in Agrobacterium tumefaciens phage Milano. Nat Commun 2024; 15:756. [PMID: 38272938 PMCID: PMC10811340 DOI: 10.1038/s41467-024-44959-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 01/10/2024] [Indexed: 01/27/2024] Open
Abstract
A contractile sheath and rigid tube assembly is a widespread apparatus used by bacteriophages, tailocins, and the bacterial type VI secretion system to penetrate cell membranes. In this mechanism, contraction of an external sheath powers the motion of an inner tube through the membrane. The structure, energetics, and mechanism of the machinery imply rigidity and straightness. The contractile tail of Agrobacterium tumefaciens bacteriophage Milano is flexible and bent to varying degrees, which sets it apart from other contractile tail-like systems. Here, we report structures of the Milano tail including the sheath-tube complex, baseplate, and putative receptor-binding proteins. The flexible-to-rigid transformation of the Milano tail upon contraction can be explained by unique electrostatic properties of the tail tube and sheath. All components of the Milano tail, including sheath subunits, are crosslinked by disulfides, some of which must be reduced for contraction to occur. The putative receptor-binding complex of Milano contains a tailspike, a tail fiber, and at least two small proteins that form a garland around the distal ends of the tailspikes and tail fibers. Despite being flagellotropic, Milano lacks thread-like tail filaments that can wrap around the flagellum, and is thus likely to employ a different binding mechanism.
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Affiliation(s)
- Ravi R Sonani
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - Lee K Palmer
- Mass Spectrometry Facility, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Nathaniel C Esteves
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Abigail A Horton
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Amanda L Sebastian
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Rebecca J Kelly
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Fengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Mark A B Kreutzberger
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - William K Russell
- Mass Spectrometry Facility, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Petr G Leiman
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
| | - Birgit E Scharf
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA.
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7
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Esteves NC, Bigham DN, Scharf BE. Phages on filaments: A genetic screen elucidates the complex interactions between Salmonella enterica flagellin and bacteriophage Chi. PLoS Pathog 2023; 19:e1011537. [PMID: 37535496 PMCID: PMC10399903 DOI: 10.1371/journal.ppat.1011537] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/04/2023] [Indexed: 08/05/2023] Open
Abstract
The bacterial flagellum is a rotary motor organelle and important virulence factor that propels motile pathogenic bacteria, such as Salmonella enterica, through their surroundings. Bacteriophages, or phages, are viruses that solely infect bacteria. As such, phages have myriad applications in the healthcare field, including phage therapy against antibiotic-resistant bacterial pathogens. Bacteriophage χ (Chi) is a flagellum-dependent (flagellotropic) bacteriophage, which begins its infection cycle by attaching its long tail fiber to the S. enterica flagellar filament as its primary receptor. The interactions between phage and flagellum are poorly understood, as are the reasons that χ only kills certain Salmonella serotypes while others entirely evade phage infection. In this study, we used molecular cloning, targeted mutagenesis, heterologous flagellin expression, and phage-host interaction assays to determine which domains within the flagellar filament protein flagellin mediate this complex interaction. We identified the antigenic N- and C-terminal D2 domains as essential for phage χ binding, with the hypervariable central D3 domain playing a less crucial role. Here, we report that the primary structure of the Salmonella flagellin D2 domains is the major determinant of χ adhesion. The phage susceptibility of a strain is directly tied to these domains. We additionally uncovered important information about flagellar function. The central and most variable domain, D3, is not required for motility in S. Typhimurium 14028s, as it can be deleted or its sequence composition can be significantly altered with minimal impacts on motility. Further knowledge about the complex interactions between flagellotropic phage χ and its primary bacterial receptor may allow genetic engineering of its host range for use as targeted antimicrobial therapy against motile pathogens of the χ-host genera Salmonella, Escherichia, or Serratia.
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Affiliation(s)
- Nathaniel C. Esteves
- Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Danielle N. Bigham
- Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Birgit E. Scharf
- Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
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8
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Dunstan RA, Bamert RS, Tan KS, Imbulgoda U, Barlow CK, Taiaroa G, Pickard DJ, Schittenhelm RB, Dougan G, Short FL, Lithgow T. Epitopes in the capsular polysaccharide and the porin OmpK36 receptors are required for bacteriophage infection of Klebsiella pneumoniae. Cell Rep 2023; 42:112551. [PMID: 37224021 DOI: 10.1016/j.celrep.2023.112551] [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: 08/30/2022] [Revised: 03/09/2023] [Accepted: 05/05/2023] [Indexed: 05/26/2023] Open
Abstract
To kill bacteria, bacteriophages (phages) must first bind to a receptor, triggering the release of the phage DNA into the bacterial cell. Many bacteria secrete polysaccharides that had been thought to shield bacterial cells from phage attack. We use a comprehensive genetic screen to distinguish that the capsule is not a shield but is instead a primary receptor enabling phage predation. Screening of a transposon library to select phage-resistant Klebsiella shows that the first receptor-binding event docks to saccharide epitopes in the capsule. We discover a second step of receptor binding, dictated by specific epitopes in an outer membrane protein. This additional and necessary event precedes phage DNA release to establish a productive infection. That such discrete epitopes dictate two essential binding events for phages has profound implications for understanding the evolution of phage resistance and what dictates host range, two issues critically important to translating knowledge of phage biology into phage therapies.
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Affiliation(s)
- Rhys A Dunstan
- Centre to Impact AMR, Monash University, Clayton, VIC, Australia; Infection Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia.
| | - Rebecca S Bamert
- Centre to Impact AMR, Monash University, Clayton, VIC, Australia; Infection Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Kher Shing Tan
- Centre to Impact AMR, Monash University, Clayton, VIC, Australia; Infection Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Uvini Imbulgoda
- Centre to Impact AMR, Monash University, Clayton, VIC, Australia; Infection Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Christopher K Barlow
- Monash Proteomics & Metabolomics Platform, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - George Taiaroa
- Department of Infectious Diseases, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Clayton, VIC, Australia
| | - Derek J Pickard
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Ralf B Schittenhelm
- Monash Proteomics & Metabolomics Platform, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Francesca L Short
- Centre to Impact AMR, Monash University, Clayton, VIC, Australia; Infection Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia; Department of Medicine, University of Cambridge, Cambridge, UK; Wellcome Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Trevor Lithgow
- Centre to Impact AMR, Monash University, Clayton, VIC, Australia; Infection Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia.
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9
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Pourcel C, Ouldali M, Tavares P, Essoh C. The saclayvirus Aci01-1 very long and complex fiber and its receptor at the Acinetobacter baumannii surface. Arch Virol 2023; 168:187. [PMID: 37351676 DOI: 10.1007/s00705-023-05817-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/16/2023] [Indexed: 06/24/2023]
Abstract
The Acinetobacter baumannii bacteriophage Aci01-1, which belongs to the genus Saclayvirus of the order Caudoviricetes, has an icosahedral head and a contractile rigid tail. We report that Aci01-1 has, attached to the tail conical tip, a remarkable 146-nm-long flexible fiber with seven beads and a terminal knot. Its putative gene coding for a 241.36-kDa tail fiber protein is homologous to genes in Aci01-1-related and unrelated phages. Analysis of its 3D structure using AlphaFold provides a structural model for the fiber observed by electron microscopy. We also identified a putative receptor of the phage on the bacterial capsule that is hypothesized to interact with the Aci01-1 long fiber.
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Affiliation(s)
- Christine Pourcel
- CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, 91198, Gif-sur-Yvette, France.
| | - Malika Ouldali
- CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, 91198, Gif-sur-Yvette, France
| | - Paulo Tavares
- CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, 91198, Gif-sur-Yvette, France
| | - Christiane Essoh
- Department of Biochemistry-Genetic, School of Biological Sciences, Université Peleforo Gon Coulibaly, Korhogo, Côte d'Ivoire
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10
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Karabasov SA, Zaitsev MA, Nerukh DA. The nut-and-bolt motion of a bacteriophage sliding along a bacterial flagellum: a complete hydrodynamics model. Sci Rep 2023; 13:9077. [PMID: 37277440 DOI: 10.1038/s41598-023-36186-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/26/2023] [Indexed: 06/07/2023] Open
Abstract
The 'nut-and-bolt' mechanism of a bacteriophage-bacteria flagellum translocation motion is modelled by numerically integrating the 3D Stokes equations using a Finite-Element Method (FEM). Following the works by Katsamba and Lauga (Phys Rev Fluids 4(1): 013101, 2019), two mechanical models of the flagellum-phage complex are considered. In the first model, the phage fiber wraps around the smooth flagellum surface separated by some distance. In the second model, the phage fiber is partly immersed in the flagellum volume via a helical groove imprinted in the flagellum and replicating the fiber shape. In both cases, the results of the Stokes solution for the translocation speed are compared with the Resistive Force Theory (RFT) solutions (obtained in Katsamba and Lauga Phys Rev Fluids 4(1): 013101, 2019) and the asymptotic theory in a limiting case. The previous RFT solutions of the same mechanical models of the flagellum-phage complex showed opposite trends for how the phage translocation speed depends on the phage tail length. The current work uses complete hydrodynamics solutions, which are free from the RFT assumptions to understand the divergence of the two mechanical models of the same biological system. A parametric investigation is performed by changing pertinent geometrical parameters of the flagellum-phage complex and computing the resulting phage translocation speed. The FEM solutions are compared with the RFT results using insights provided from the velocity field visualisation in the fluid domain.
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Affiliation(s)
- Sergey A Karabasov
- School of Engineering and Materials Science, Queen Mary University of London, London, E1 4NS, UK.
| | | | - Dmitry A Nerukh
- Department of Mathematics, Aston University, Birmingham, B4 7ET, UK
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11
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Jiang J, Lan G, Li J, Yu J, Huang H, Sun Y, Xu C, Liu D, Gong Y, Zhao C. Characterization and genomic analysis of JC01, a novel bacteriophage infecting Cronobacter sakazakii. Arch Virol 2023; 168:1. [PMID: 36527491 PMCID: PMC9759504 DOI: 10.1007/s00705-022-05663-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 10/24/2022] [Indexed: 12/23/2022]
Abstract
The lytic bacteriophage JC01 was isolated using a strain of Cronobacter sakazakii previously isolated from powdered infant formula (PIF). The complete genome sequence of phage JC01 was determined. The double-stranded DNA genome of phage JC01 is composed of 61,736 bp with a G + C content of 58.9%, and it contains 76 putative open reading frames (ORFs) without any tRNA genes. The predicted ORFs were classified into functional groups, including DNA manipulation, transcription, phage packaging, phage structure, host lysis, and hypothetical proteins. Based on overall nucleotide sequence comparisons, calculation of phage intergenomic similarities, and phylogenetic analysis, JC01 appears to be a novel bacteriophage infecting C. sakazakii.
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Affiliation(s)
- Jie Jiang
- grid.64924.3d0000 0004 1760 5735Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 130021 Changchun, Jilin People’s Republic of China
| | - Guanda Lan
- grid.64924.3d0000 0004 1760 5735Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 130021 Changchun, Jilin People’s Republic of China
| | - Jinghua Li
- grid.64924.3d0000 0004 1760 5735Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 130021 Changchun, Jilin People’s Republic of China
| | - Jun Yu
- grid.64924.3d0000 0004 1760 5735Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 130021 Changchun, Jilin People’s Republic of China
| | - Honglan Huang
- grid.64924.3d0000 0004 1760 5735Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 130021 Changchun, Jilin People’s Republic of China
| | - Yanbo Sun
- grid.64924.3d0000 0004 1760 5735Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 130021 Changchun, Jilin People’s Republic of China
| | - Cuiting Xu
- grid.64924.3d0000 0004 1760 5735Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 130021 Changchun, Jilin People’s Republic of China
| | - Dandan Liu
- grid.64924.3d0000 0004 1760 5735Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 130021 Changchun, Jilin People’s Republic of China
| | - Yunwei Gong
- Changchun Center for Diseases Control and Prevention, Changchun, People’s Republic of China
| | - Chunyan Zhao
- grid.64924.3d0000 0004 1760 5735Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 130021 Changchun, Jilin People’s Republic of China
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12
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Casjens SR, Davidson AR, Grose JH. The small genome, virulent, non-contractile tailed bacteriophages that infect Enterobacteriales hosts. Virology 2022; 573:151-166. [DOI: 10.1016/j.virol.2022.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 05/07/2022] [Accepted: 06/01/2022] [Indexed: 11/25/2022]
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13
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Flagellotropic Bacteriophages: Opportunities and Challenges for Antimicrobial Applications. Int J Mol Sci 2022; 23:ijms23137084. [PMID: 35806089 PMCID: PMC9266447 DOI: 10.3390/ijms23137084] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/18/2022] [Accepted: 06/21/2022] [Indexed: 12/22/2022] Open
Abstract
Bacteriophages (phages) are the most abundant biological entities in the biosphere. As viruses that solely infect bacteria, phages have myriad healthcare and agricultural applications including phage therapy and antibacterial treatments in the foodservice industry. Phage therapy has been explored since the turn of the twentieth century but was no longer prioritized following the invention of antibiotics. As we approach a post-antibiotic society, phage therapy research has experienced a significant resurgence for the use of phages against antibiotic-resistant bacteria, a growing concern in modern medicine. Phages are extraordinarily diverse, as are their host receptor targets. Flagellotropic (flagellum-dependent) phages begin their infection cycle by attaching to the flagellum of their motile host, although the later stages of the infection process of most of these phages remain elusive. Flagella are helical appendages required for swimming and swarming motility and are also of great importance for virulence in many pathogenic bacteria of clinical relevance. Not only is bacterial motility itself frequently important for virulence, as it allows pathogenic bacteria to move toward their host and find nutrients more effectively, but flagella can also serve additional functions including mediating bacterial adhesion to surfaces. Flagella are also a potent antigen recognized by the human immune system. Phages utilizing the flagellum for infections are of particular interest due to the unique evolutionary tradeoff they force upon their hosts: by downregulating or abolishing motility to escape infection by a flagellotropic phage, a pathogenic bacterium would also likely attenuate its virulence. This factor may lead to flagellotropic phages becoming especially potent antibacterial agents. This review outlines past, present, and future research of flagellotropic phages, including their molecular mechanisms of infection and potential future applications.
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14
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Cobbley HK, Evans SI, Brown HMF, Eberhard B, Eberhard N, Kim M, Moe HM, Schaeffer D, Sharma R, Thompson DW, Casjens SR, Grose JH. Complete Genome Sequences of Six Chi-Like Bacteriophages That Infect Proteus and Klebsiella. Microbiol Resour Announc 2022; 11:e0121521. [PMID: 35297681 PMCID: PMC9022528 DOI: 10.1128/mra.01215-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/01/2022] [Indexed: 11/20/2022] Open
Abstract
Proteus mirabilis and Klebsiella aerogenes are Gram-negative opportunistic pathogens that are responsible for nosocomial and health care-associated infections, including urinary tract infections. Here, the full genome sequences of six Chi-like Proteus (DanisaurMW, DoubleBarrel, Inception, Jing313, and NotEvenPhaged) or Klebsiella (Phraden) bacteriophages are announced, contributing to the understanding of Chi-like phages.
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Affiliation(s)
- Hunter K Cobbley
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Seth I Evans
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Hannah M F Brown
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Braden Eberhard
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Nathaniel Eberhard
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Minji Kim
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Haley Mickelsen Moe
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Daniel Schaeffer
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Ruchira Sharma
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Daniel W Thompson
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Sherwood R Casjens
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Julianne H Grose
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
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15
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Characterization of Blf4, an Archaeal Lytic Virus Targeting a Member of the Methanomicrobiales. Viruses 2021; 13:v13101934. [PMID: 34696364 PMCID: PMC8540584 DOI: 10.3390/v13101934] [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: 07/12/2021] [Revised: 09/14/2021] [Accepted: 09/20/2021] [Indexed: 01/05/2023] Open
Abstract
Today, the number of known viruses infecting methanogenic archaea is limited. Here, we report on a novel lytic virus, designated Blf4, and its host strain Methanoculleus bourgensis E02.3, a methanogenic archaeon belonging to the Methanomicrobiales, both isolated from a commercial biogas plant in Germany. The virus consists of an icosahedral head 60 nm in diameter and a long non-contractile tail of 125 nm in length, which is consistent with the new isolate belonging to the Siphoviridae family. Electron microscopy revealed that Blf4 attaches to the vegetative cells of M. bourgensis E02.3 as well as to cellular appendages. Apart from M. bourgensis E02.3, none of the tested Methanoculleus strains were lysed by Blf4, indicating a narrow host range. The complete 37 kb dsDNA genome of Blf4 contains 63 open reading frames (ORFs), all organized in the same transcriptional direction. For most of the ORFs, potential functions were predicted. In addition, the genome of the host M. bourgensis E02.3 was sequenced and assembled, resulting in a 2.6 Mbp draft genome consisting of nine contigs. All genes required for a hydrogenotrophic lifestyle were predicted. A CRISPR/Cas system (type I-U) was identified with six spacers directed against Blf4, indicating that this defense system might not be very efficient in fending off invading Blf4 virus.
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16
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Dunstan RA, Bamert RS, Belousoff MJ, Short FL, Barlow CK, Pickard DJ, Wilksch JJ, Schittenhelm RB, Strugnell RA, Dougan G, Lithgow T. Mechanistic Insights into the Capsule-Targeting Depolymerase from a Klebsiella pneumoniae Bacteriophage. Microbiol Spectr 2021; 9:e0102321. [PMID: 34431721 PMCID: PMC8552709 DOI: 10.1128/spectrum.01023-21] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 08/02/2021] [Indexed: 02/07/2023] Open
Abstract
The production of capsular polysaccharides by Klebsiella pneumoniae protects the bacterial cell from harmful environmental factors such as antimicrobial compounds and infection by bacteriophages (phages). To bypass this protective barrier, some phages encode polysaccharide-degrading enzymes referred to as depolymerases to provide access to cell surface receptors. Here, we characterized the phage RAD2, which infects K. pneumoniae strains that produce the widespread, hypervirulence-associated K2-type capsular polysaccharide. Using transposon-directed insertion sequencing, we have shown that the production of capsule is an absolute requirement for efficient RAD2 infection by serving as a first-stage receptor. We have identified the depolymerase responsible for recognition and degradation of the capsule, determined that the depolymerase forms globular appendages on the phage virion tail tip, and present the cryo-electron microscopy structure of the RAD2 capsule depolymerase at 2.7-Å resolution. A putative active site for the enzyme was identified, comprising clustered negatively charged residues that could facilitate the hydrolysis of target polysaccharides. Enzymatic assays coupled with mass spectrometric analyses of digested oligosaccharide products provided further mechanistic insight into the hydrolase activity of the enzyme, which, when incubated with K. pneumoniae, removes the capsule and sensitizes the cells to serum-induced killing. Overall, these findings expand our understanding of how phages target the Klebsiella capsule for infection, providing a framework for the use of depolymerases as antivirulence agents against this medically important pathogen. IMPORTANCE Klebsiella pneumoniae is a medically important pathogen that produces a thick protective capsule that is essential for pathogenicity. Phages are natural predators of bacteria, and many encode diverse "capsule depolymerases" which specifically degrade the capsule of their hosts, an exploitable trait for potential therapies. We have determined the first structure of a depolymerase that targets the clinically relevant K2 capsule and have identified its putative active site, providing hints to its mechanism of action. We also show that Klebsiella cells treated with a recombinant form of the depolymerase are stripped of capsule, inhibiting their ability to grow in the presence of serum, demonstrating the anti-infective potential of these robust and readily producible enzymes against encapsulated bacterial pathogens such as K. pneumoniae.
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Affiliation(s)
- Rhys A. Dunstan
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Rebecca S. Bamert
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Matthew J. Belousoff
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Francesca L. Short
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
- Wellcome Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Christopher K. Barlow
- Monash Proteomics & Metabolomics Facility, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Derek J. Pickard
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Jonathan J. Wilksch
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Ralf B. Schittenhelm
- Monash Proteomics & Metabolomics Facility, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Richard A. Strugnell
- Department of Microbiology and Immunology, The Peter Doherty Institute, The University of Melbourne, Parkville, Australia
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
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17
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Xie Y, Thompson T, O'Leary C, Crosby S, Nguyen QX, Liu M, Gill JJ. Differential Bacteriophage Efficacy in Controlling Salmonella in Cattle Hide and Soil Models. Front Microbiol 2021; 12:657524. [PMID: 34262535 PMCID: PMC8273493 DOI: 10.3389/fmicb.2021.657524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 06/04/2021] [Indexed: 01/18/2023] Open
Abstract
Asymptomatic Salmonella carriage in beef cattle is a food safety concern and the beef feedlot environment and cattle hides are reservoirs of this pathogen. Bacteriophages present an attractive non-antibiotic strategy for control of Salmonella in beef. In this study, four diverse and genetically unrelated Salmonella phages, Sergei, Season12, Sw2, and Munch, were characterized and tested alone and in combination for their ability to control Salmonella in cattle hide and soil systems, which are relevant models for Salmonella control in beef production. Phage Sergei is a member of the genus Sashavirus, phage Season12 was identified as a member of the Chivirus genus, Sw2 was identified as a member of the T5-like Epseptimavirus genus, and Munch was found to be a novel “jumbo” myovirus. Observed pathogen reductions in the model systems ranged from 0.50 to 1.75 log10 CFU/cm2 in hides and from 0.53 to 1.38 log10 CFU/g in soil, with phages Sergei and Sw2 producing greater reductions (∼1 log10 CFU/cm2 or CFU/g) than Season12 and Munch. These findings are in accordance with previous observations of phage virulence, suggesting the simple ability of a phage to form plaques on a bacterial strain is not a strong indicator of antimicrobial activity, but performance in liquid culture assays provides a better predictor. The antimicrobial efficacies of phage treatments were found to be phage-specific across model systems, implying that a phage capable of achieving bacterial reduction in one model is more likely to perform well in another. Phage combinations did not produce significantly greater efficacy than single phages even after 24 h in the soil model, and phage-insensitive colonies were not isolated from treated samples, suggesting that the emergence of phage resistance was not a major factor limiting efficacy in this system.
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Affiliation(s)
- Yicheng Xie
- Department of Animal Science, Texas A&M University, College Station, TX, United States.,Center for Phage Technology, Texas A&M University, College Station, TX, United States
| | - Tyler Thompson
- Department of Animal Science, Texas A&M University, College Station, TX, United States
| | - Chandler O'Leary
- Center for Phage Technology, Texas A&M University, College Station, TX, United States.,Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
| | - Stephen Crosby
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
| | - Quang X Nguyen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
| | - Mei Liu
- Center for Phage Technology, Texas A&M University, College Station, TX, United States
| | - Jason J Gill
- Department of Animal Science, Texas A&M University, College Station, TX, United States.,Center for Phage Technology, Texas A&M University, College Station, TX, United States
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18
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Component Parts of Bacteriophage Virions Accurately Defined by a Machine-Learning Approach Built on Evolutionary Features. mSystems 2021; 6:e0024221. [PMID: 34042467 PMCID: PMC8269216 DOI: 10.1128/msystems.00242-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial resistance (AMR) continues to evolve as a major threat to human health, and new strategies are required for the treatment of AMR infections. Bacteriophages (phages) that kill bacterial pathogens are being identified for use in phage therapies, with the intention to apply these bactericidal viruses directly into the infection sites in bespoke phage cocktails. Despite the great unsampled phage diversity for this purpose, an issue hampering the roll out of phage therapy is the poor quality annotation of many of the phage genomes, particularly for those from infrequently sampled environmental sources. We developed a computational tool called STEP3 to use the “evolutionary features” that can be recognized in genome sequences of diverse phages. These features, when integrated into an ensemble framework, achieved a stable and robust prediction performance when benchmarked against other prediction tools using phages from diverse sources. Validation of the prediction accuracy of STEP3 was conducted with high-resolution mass spectrometry analysis of two novel phages, isolated from a watercourse in the Southern Hemisphere. STEP3 provides a robust computational approach to distinguish specific and universal features in phages to improve the quality of phage cocktails and is available for use at http://step3.erc.monash.edu/. IMPORTANCE In response to the global problem of antimicrobial resistance, there are moves to use bacteriophages (phages) as therapeutic agents. Selecting which phages will be effective therapeutics relies on interpreting features contributing to shelf-life and applicability to diagnosed infections. However, the protein components of the phage virions that dictate these properties vary so much in sequence that best estimates suggest failure to recognize up to 90% of them. We have utilized this diversity in evolutionary features as an advantage, to apply machine learning for prediction accuracy for diverse components in phage virions. We benchmark this new tool showing the accurate recognition and evaluation of phage component parts using genome sequence data of phages from undersampled environments, where the richest diversity of phage still lies.
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19
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Yu Z, Schwarz C, Zhu L, Chen L, Shen Y, Yu P. Hitchhiking Behavior in Bacteriophages Facilitates Phage Infection and Enhances Carrier Bacteria Colonization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:2462-2472. [PMID: 33381966 DOI: 10.1021/acs.est.0c06969] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Interactions between bacteriophages (phages) and biofilms remain poorly understood despite the broad implications for microbial ecology, water quality, and microbiome engineering. Here, we demonstrate that lytic coliphage PHH01 can hitchhike on carrier bacteria Bacillus cereus to facilitate its infection of host bacteria, Escherichia coli, in biofilms. Specifically, PHH01 could adsorb onto the flagella of B. cereus, and thus phage motility was increased, resulting in 4.36-fold more effective infection of E. coli in biofilm relative to free PHH01 alone. Moreover, phage infection mitigated interspecies competition and enhanced B. cereus colonization; the fraction of B. cereus in the final biofilm increased from 9% without phages to 43% with phages. The mutualistic relationship between the coliphage and carrier bacteria was substantiated by migration tests on an E. coli lawn: the conjugation of PHH01 and B. cereus enhanced B. cereus colonization by 6.54-fold compared to B. cereus alone (6.15 vs 0.94 cm2 in 24 h) and PHH01 migration by 5.15-fold compared to PHH01 alone (10.3 vs 2.0 mm in 24 h). Metagenomic and electron microscopic analysis revealed that the phages of diverse taxonomies and different morphologies could be adsorbed by the flagella of B. cereus, suggesting hitchhiking on flagellated bacteria might be a widespread strategy in aquatic phage populations. Overall, our study highlights that hitchhiking behavior in phages can facilitate phage infection of biofilm bacteria, promote carrier bacteria colonization, and thus significantly influence biofilm composition, which holds promise for mediating biofilm functions and moderating associated risks.
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Affiliation(s)
- Zhuodong Yu
- School of Environment and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Cory Schwarz
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Liang Zhu
- School of Environment and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Linlin Chen
- School of Environment and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yun Shen
- Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, United States
| | - Pingfeng Yu
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
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20
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Flagellar Structures from the Bacterium Caulobacter crescentus and Implications for Phage ϕ CbK Predation of Multiflagellin Bacteria. J Bacteriol 2021; 203:JB.00399-20. [PMID: 33288623 DOI: 10.1128/jb.00399-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 12/02/2020] [Indexed: 02/06/2023] Open
Abstract
Caulobacter crescentus is a Gram-negative alphaproteobacterium that commonly lives in oligotrophic fresh- and saltwater environments. C. crescentus is a host to many bacteriophages, including ϕCbK and ϕCbK-like bacteriophages, which require interaction with the bacterial flagellum and pilus complexes during adsorption. It is commonly thought that the six paralogs of the flagellin gene present in C. crescentus are important for bacteriophage evasion. Here, we show that deletion of specific flagellins in C. crescentus can indeed attenuate ϕCbK adsorption efficiency, although no single deletion completely ablates ϕCbK adsorption. Thus, the bacteriophage ϕCbK likely recognizes a common motif among the six known flagellins in C. crescentus with various degrees of efficiency. Interestingly, we observe that most deletion strains still generate flagellar filaments, with the exception of a strain that contains only the most divergent flagellin, FljJ, or a strain that contains only FljN and FljO. To visualize the surface residues that are likely recognized by ϕCbK, we determined two high-resolution structures of the FljK filament, with and without an amino acid substitution that induces straightening of the filament. We observe posttranslational modifications on conserved surface threonine residues of FljK that are likely O-linked glycans. The possibility of interplay between these modifications and ϕCbK adsorption is discussed. We also determined the structure of a filament composed of a heterogeneous mixture of FljK and FljL, the final resolution of which was limited to approximately 4.6 Å. Altogether, this work builds a platform for future investigations of how phage ϕCbK infects C. crescentus at the molecular level.IMPORTANCE Bacterial flagellar filaments serve as an initial attachment point for many bacteriophages to bacteria. Some bacteria harbor numerous flagellin genes and are therefore able to generate flagellar filaments with complex compositions, which is thought to be important for evasion from bacteriophages. This study characterizes the importance of the six flagellin genes in C. crescentus for infection by bacteriophage ϕCbK. We find that filaments containing the FljK flagellin are the preferred substrate for bacteriophage ϕCbK. We also present a high-resolution structure of a flagellar filament containing only the FljK flagellin, which provides a platform for future studies on determining how bacteriophage ϕCbK attaches to flagellar filaments at the molecular level.
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21
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Hardy JM, Dunstan RA, Grinter R, Belousoff MJ, Wang J, Pickard D, Venugopal H, Dougan G, Lithgow T, Coulibaly F. The architecture and stabilisation of flagellotropic tailed bacteriophages. Nat Commun 2020; 11:3748. [PMID: 32719311 PMCID: PMC7385642 DOI: 10.1038/s41467-020-17505-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 07/01/2020] [Indexed: 12/31/2022] Open
Abstract
Flagellotropic bacteriophages engage flagella to reach the bacterial surface as an effective means to increase the capture radius for predation. Structural details of these viruses are of great interest given the substantial drag forces and torques they face when moving down the spinning flagellum. We show that the main capsid and auxiliary proteins form two nested chainmails that ensure the integrity of the bacteriophage head. Core stabilising structures are conserved in herpesviruses suggesting their ancestral origin. The structure of the tail also reveals a robust yet pliable assembly. Hexameric rings of the tail-tube protein are braced by the N-terminus and a β-hairpin loop, and interconnected along the tail by the splayed β-hairpins. By contrast, we show that the β-hairpin has an inhibitory role in the tail-tube precursor, preventing uncontrolled self-assembly. Dyads of acidic residues inside the tail-tube present regularly-spaced motifs well suited to DNA translocation into bacteria through the tail.
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Affiliation(s)
- Joshua M Hardy
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Rhys A Dunstan
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Rhys Grinter
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Matthew J Belousoff
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Jiawei Wang
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Derek Pickard
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Hariprasad Venugopal
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, VIC, Australia
| | - Gordon Dougan
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Trevor Lithgow
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia.
| | - Fasséli Coulibaly
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia.
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22
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Mangalea MR, Duerkop BA. Fitness Trade-Offs Resulting from Bacteriophage Resistance Potentiate Synergistic Antibacterial Strategies. Infect Immun 2020; 88:e00926-19. [PMID: 32094257 PMCID: PMC7309606 DOI: 10.1128/iai.00926-19] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Bacteria that cause life-threatening infections in humans are becoming increasingly difficult to treat. In some instances, this is due to intrinsic and acquired antibiotic resistance, indicating that new therapeutic approaches are needed to combat bacterial pathogens. There is renewed interest in utilizing viruses of bacteria known as bacteriophages (phages) as potential antibacterial therapeutics. However, critics suggest that similar to antibiotics, the development of phage-resistant bacteria will halt clinical phage therapy. Although the emergence of phage-resistant bacteria is likely inevitable, there is a growing body of literature showing that phage selective pressure promotes mutations in bacteria that allow them to subvert phage infection, but with a cost to their fitness. Such fitness trade-offs include reduced virulence, resensitization to antibiotics, and colonization defects. Resistance to phage nucleic acid entry, primarily via cell surface modifications, compromises bacterial fitness during antibiotic and host immune system pressure. In this minireview, we explore the mechanisms behind phage resistance in bacterial pathogens and the physiological consequences of acquiring phage resistance phenotypes. With this knowledge, it may be possible to use phages to alter bacterial populations, making them more tractable to current therapeutic strategies.
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Affiliation(s)
- Mihnea R Mangalea
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Breck A Duerkop
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
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