1
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Fraikin N, Couturier A, Lesterlin C. The winding journey of conjugative plasmids toward a novel host cell. Curr Opin Microbiol 2024; 78:102449. [PMID: 38432159 DOI: 10.1016/j.mib.2024.102449] [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: 01/04/2024] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 03/05/2024]
Abstract
Horizontal transfer of plasmids by conjugation is a fundamental mechanism driving the widespread dissemination of drug resistance among bacterial populations. The successful colonization of a new host cell necessitates the plasmid to navigate through a series of sequential steps, each dependent on specific plasmid or host factors. This review explores recent advancements in comprehending the cellular and molecular mechanisms that govern plasmid transmission, establishment, and long-term maintenance. Adopting a plasmid-centric perspective, we describe the critical steps and bottlenecks in the plasmid's journey toward a new host cell, encompassing exploration and contact initiation, invasion, establishment and control, and assimilation.
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Affiliation(s)
- Nathan Fraikin
- Molecular Microbiology and Structural Biochemistry (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, 69007 Lyon, France
| | - Agathe Couturier
- Molecular Microbiology and Structural Biochemistry (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, 69007 Lyon, France
| | - Christian Lesterlin
- Molecular Microbiology and Structural Biochemistry (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, 69007 Lyon, France.
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2
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Mayo-Muñoz D, Pinilla-Redondo R, Camara-Wilpert S, Birkholz N, Fineran PC. Inhibitors of bacterial immune systems: discovery, mechanisms and applications. Nat Rev Genet 2024; 25:237-254. [PMID: 38291236 DOI: 10.1038/s41576-023-00676-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2023] [Indexed: 02/01/2024]
Abstract
To contend with the diversity and ubiquity of bacteriophages and other mobile genetic elements, bacteria have developed an arsenal of immune defence mechanisms. Bacterial defences include CRISPR-Cas, restriction-modification and a growing list of mechanistically diverse systems, which constitute the bacterial 'immune system'. As a response, bacteriophages and mobile genetic elements have evolved direct and indirect mechanisms to circumvent or block bacterial defence pathways and ensure successful infection. Recent advances in methodological and computational approaches, as well as the increasing availability of genome sequences, have boosted the discovery of direct inhibitors of bacterial defence systems. In this Review, we discuss methods for the discovery of direct inhibitors, their diverse mechanisms of action and perspectives on their emerging applications in biotechnology and beyond.
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Affiliation(s)
- David Mayo-Muñoz
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Rafael Pinilla-Redondo
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
- Section of Microbiology, University of Copenhagen, Copenhagen, Denmark.
| | | | - Nils Birkholz
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
- Genetics Otago, University of Otago, Dunedin, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand.
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand.
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3
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Ryan MP, Carraro N, Slattery S, Pembroke JT. Integrative Conjugative Elements (ICEs) of the SXT/R391 family drive adaptation and evolution in γ-Proteobacteria. Crit Rev Microbiol 2024; 50:105-126. [PMID: 36634159 DOI: 10.1080/1040841x.2022.2161870] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 12/19/2022] [Indexed: 01/13/2023]
Abstract
Integrative Conjugative Elements (ICEs) are mosaics containing functional modules allowing maintenance by site-specific integration and excision into and from the host genome and conjugative transfer to a specific host range. Many ICEs encode a range of adaptive functions that aid bacterial survival and evolution in a range of niches. ICEs from the SXT/R391 family are found in γ-Proteobacteria. Over 100 members have undergone epidemiological and molecular characterization allowing insight into their diversity and function. Comparative analysis of SXT/R391 elements from a wide geographic distribution has revealed conservation of key functions, and the accumulation and evolution of adaptive genes. This evolution is associated with gene acquisition in conserved hotspots and variable regions within the SXT/R391 ICEs catalysed via element-encoded recombinases. The elements can carry IS elements and transposons, and a mutagenic DNA polymerase, PolV, which are associated with their evolution. SXT/R391 ICEs isolated from different niches appear to have retained adaptive functions related to that specific niche; phage resistance determinants in ICEs carried by wastewater bacteria, antibiotic resistance determinants in clinical isolates and metal resistance determinants in bacteria recovered from polluted environments/ocean sediments. Many genes found in the element hotspots are undetermined and have few homologs in the nucleotide databases.
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Affiliation(s)
- Michael P Ryan
- Department of Applied Sciences, Technological University of the Shannon, Limerick, Ireland
| | - Nicolas Carraro
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Shannon Slattery
- Department of Chemical Sciences, School of Natural Sciences, University of Limerick, Ireland
| | - J Tony Pembroke
- Department of Chemical Sciences, School of Natural Sciences, University of Limerick, Ireland
- Bernal Institute, University of Limerick, Ireland
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4
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Hamilton T, Joris BR, Shrestha A, Browne TS, Rodrigue S, Karas BJ, Gloor GB, Edgell DR. De Novo Synthesis of a Conjugative System from Human Gut Metagenomic Data for Targeted Delivery of Cas9 Antimicrobials. ACS Synth Biol 2023; 12:3578-3590. [PMID: 38049144 PMCID: PMC10729033 DOI: 10.1021/acssynbio.3c00319] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/03/2023] [Accepted: 11/08/2023] [Indexed: 12/06/2023]
Abstract
Metagenomic sequences represent an untapped source of genetic novelty, particularly for conjugative systems that could be used for plasmid-based delivery of Cas9-derived antimicrobial agents. However, unlocking the functional potential of conjugative systems purely from metagenomic sequences requires the identification of suitable candidate systems as starting scaffolds for de novo DNA synthesis. Here, we developed a bioinformatics approach that searches through the metagenomic "trash bin" for genes associated with conjugative systems present on contigs that are typically excluded from common metagenomic analysis pipelines. Using a human metagenomic gut data set representing 2805 taxonomically distinct units, we identified 1598 contigs containing conjugation genes with a differential distribution in human cohorts. We synthesized de novo an entire Citrobacter spp. conjugative system of 54 kb containing at least 47 genes and assembled it into a plasmid, pCitro. We found that pCitro conjugates from Escherichia coli to Citrobacter rodentium with a 30-fold higher frequency than to E. coli, and is compatible with Citrobacter resident plasmids. Mutations in the traV and traY conjugation components of pCitro inhibited conjugation. We showed that pCitro can be repurposed as an antimicrobial delivery agent by programming it with the TevCas9 nuclease and Citrobacter-specific sgRNAs to kill C. rodentium. Our study reveals a trove of uncharacterized conjugative systems in metagenomic data and describes an experimental framework to animate these large genetic systems as novel target-adapted delivery vectors for Cas9-based editing of bacterial genomes.
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Affiliation(s)
- Thomas
A. Hamilton
- Department
of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London N6A 5C1, ON, Canada
| | - Benjamin R. Joris
- Department
of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London N6A 5C1, ON, Canada
| | - Arina Shrestha
- Department
of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London N6A 5C1, ON, Canada
| | - Tyler S. Browne
- Department
of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London N6A 5C1, ON, Canada
| | - Sébastien Rodrigue
- Départment
de Biologie, Université de Sherbrooke, Sherbrooke J1K 2R1, QC, Canada
| | - Bogumil J. Karas
- Department
of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London N6A 5C1, ON, Canada
| | - Gregory B. Gloor
- Department
of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London N6A 5C1, ON, Canada
| | - David R. Edgell
- Department
of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London N6A 5C1, ON, Canada
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5
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Zhu Y, Pang L, Lai S, Xie X, Zhang H, Yu J, Wu J, Qi H, Zhou Q, Feng J, Zhang A. Deciphering risks of resistomes and pathogens in intensive laying hen production chain. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161790. [PMID: 36702267 DOI: 10.1016/j.scitotenv.2023.161790] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/14/2023] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Antimicrobial resistance (AMR) and pathogens derived from food animals and their associated environments have emerged as challenging threats to humans from a health perspective, but our understanding of these risks and their key prevention and control points in the current intensive breeding industry remains poor. By creating an integral composition and risk profile of the resistome and microbiome through metagenomics in feces, flies, dust, sewage, and soil along the four-stage laying hen production chain, we found that the whole production chain is a hotspot for antimicrobial resistance genes (ARGs) with 374 known subtypes and pathogens, including 157 human pathogenic bacteria (HPB). Feces and flies were identified as major risk sources for these contaminations. Also, we confirmed a twin-risk of AMR and pathogenicity prevailing throughout the chain, but with different frequencies in each stage; thus, high-risk ARGs in the young chicken stage and highly prioritized HPB in the chick stage contributed 37.33 % to the total AMR risk and 36.36 % to the pathogenic risks, respectively, thus rendering the two stages to be the key prevention points. Moreover, the prevalence of 112 binned ARG supercarriers (for example, Klebsiella pneumoniae harboring 20 ARGs) was unraveled along the production chain, especially in feces, flies, and dust, and 87 potential hosts exhibited high pathogenic risk, high-risk AMR, or both, with 262 ARGs and 816 virulence factor genes. Overall, this study provides first-hand comprehensive data on high-risk ARGs and their pathogenic hosts in the intensive laying hen production chain, and thus is fundamentally important for developing new measures to help control the global AMR crisis induced through the animal-environment-human pathway.
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Affiliation(s)
- Yixiao Zhu
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Lina Pang
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Shanming Lai
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Xianjun Xie
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Haoyu Zhang
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Jing Yu
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Jie Wu
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Haoxuan Qi
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Quan Zhou
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Jingyi Feng
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Anyun Zhang
- Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China.
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6
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Forsberg KJ. Anti-CRISPR Discovery: Using Magnets to Find Needles in Haystacks. J Mol Biol 2023; 435:167952. [PMID: 36638909 PMCID: PMC10073268 DOI: 10.1016/j.jmb.2023.167952] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023]
Abstract
CRISPR-Cas immune systems in bacteria and archaea protect against viral infection, which has spurred viruses to develop dedicated inhibitors of these systems called anti-CRISPRs (Acrs). Like most host-virus arms races, many diverse examples of these immune and counter-immune proteins are encoded by the genomes of bacteria, archaea, and their viruses. For the case of Acrs, it is almost certain that just a small minority of nature's true diversity has been described. In this review, I discuss the various approaches used to identify these Acrs and speculate on the future for Acr discovery. Because Acrs can determine infection outcomes in nature and regulate CRISPR-Cas activities in applied settings, they have a dual importance to both host-virus conflicts and emerging biotechnologies. Thus, revealing the largely hidden world of Acrs should provide important lessons in microbiology that have the potential to ripple far beyond the field.
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Affiliation(s)
- Kevin J Forsberg
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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7
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Cooke MB, Herman C. Conjugation's Toolkit: the Roles of Nonstructural Proteins in Bacterial Sex. J Bacteriol 2023; 205:e0043822. [PMID: 36847532 PMCID: PMC10029717 DOI: 10.1128/jb.00438-22] [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] [Indexed: 03/01/2023] Open
Abstract
Bacterial conjugation, a form of horizontal gene transfer, relies on a type 4 secretion system (T4SS) and a set of nonstructural genes that are closely linked. These nonstructural genes aid in the mobile lifestyle of conjugative elements but are not part of the T4SS apparatus for conjugative transfer, such as the membrane pore and relaxosome, or the plasmid maintenance and replication machineries. While these nonstructural genes are not essential for conjugation, they assist in core conjugative functions and mitigate the cellular burden on the host. This review compiles and categorizes known functions of nonstructural genes by the stage of conjugation they modulate: dormancy, transfer, and new host establishment. Themes include establishing a commensalistic relationship with the host, manipulating the host for efficient T4SS assembly and function and assisting in conjugative evasion of recipient cell immune functions. These genes, taken in a broad ecological context, play important roles in ensuring proper propagation of the conjugation system in a natural environment.
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Affiliation(s)
- Matthew B. Cooke
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
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8
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Caldwell BJ, Norris AS, Karbowski CF, Wiegand AM, Wysocki VH, Bell CE. Structure of a RecT/Redβ family recombinase in complex with a duplex intermediate of DNA annealing. Nat Commun 2022; 13:7855. [PMID: 36543802 PMCID: PMC9772228 DOI: 10.1038/s41467-022-35572-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Some bacteriophage encode a recombinase that catalyzes single-stranded DNA annealing (SSA). These proteins are apparently related to RAD52, the primary human SSA protein. The best studied protein, Redβ from bacteriophage λ, binds weakly to ssDNA, not at all to dsDNA, but tightly to a duplex intermediate of annealing formed when two complementary DNA strands are added to the protein sequentially. We used single particle cryo-electron microscopy (cryo-EM) to determine a 3.4 Å structure of a Redβ homolog from a prophage of Listeria innocua in complex with two complementary 83mer oligonucleotides. The structure reveals a helical protein filament bound to a DNA duplex that is highly extended and unwound. Native mass spectrometry confirms that the complex seen by cryo-EM is the predominant species in solution. The protein shares a common core fold with RAD52 and a similar mode of ssDNA-binding. These data provide insights into the mechanism of protein-catalyzed SSA.
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Affiliation(s)
- Brian J Caldwell
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Andrew S Norris
- Department of Chemistry and Biochemistry and Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Caroline F Karbowski
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Alyssa M Wiegand
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Vicki H Wysocki
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA
- Department of Chemistry and Biochemistry and Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Charles E Bell
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA.
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA.
- Department of Chemistry and Biochemistry and Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH, 43210, USA.
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9
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Dimitriu T. Evolution of horizontal transmission in antimicrobial resistance plasmids. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35849537 DOI: 10.1099/mic.0.001214] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Mobile genetic elements (MGEs) are one of the main vectors for the spread of antimicrobial resistance (AMR) across bacteria, due to their ability to move horizontally between bacterial lineages. Horizontal transmission of AMR can increase AMR prevalence at multiple scales, from increasing the prevalence of infections by resistant bacteria to pathogen epidemics and worldwide spread of AMR across species. Among MGEs, conjugative plasmids are the main contributors to the spread of AMR. This review discusses the selective pressures acting on MGEs and their hosts to promote or limit the horizontal transmission of MGEs, the mechanisms by which transmission rates can evolve, and their implications for limiting the spread of AMR, with a focus on AMR plasmids.
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10
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Jaskólska M, Adams DW, Blokesch M. Two defence systems eliminate plasmids from seventh pandemic Vibrio cholerae. Nature 2022; 604:323-329. [PMID: 35388218 PMCID: PMC7613841 DOI: 10.1038/s41586-022-04546-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/11/2022] [Indexed: 12/16/2022]
Abstract
Horizontal gene transfer can trigger rapid shifts in bacterial evolution. Driven by a variety of mobile genetic elements-in particular bacteriophages and plasmids-the ability to share genes within and across species underpins the exceptional adaptability of bacteria. Nevertheless, invasive mobile genetic elements can also present grave risks to the host; bacteria have therefore evolved a vast array of defences against these elements1. Here we identify two plasmid defence systems conserved in the Vibrio cholerae El Tor strains responsible for the ongoing seventh cholera pandemic2-4. These systems, termed DdmABC and DdmDE, are encoded on two major pathogenicity islands that are a hallmark of current pandemic strains. We show that the modules cooperate to rapidly eliminate small multicopy plasmids by degradation. Moreover, the DdmABC system is widespread and can defend against bacteriophage infection by triggering cell suicide (abortive infection, or Abi). Notably, we go on to show that, through an Abi-like mechanism, DdmABC increases the burden of large low-copy-number conjugative plasmids, including a broad-host IncC multidrug resistance plasmid, which creates a fitness disadvantage that counterselects against plasmid-carrying cells. Our results answer the long-standing question of why plasmids, although abundant in environmental strains, are rare in pandemic strains; have implications for understanding the dissemination of antibiotic resistance plasmids; and provide insights into how the interplay between two defence systems has shaped the evolution of the most successful lineage of pandemic V. cholerae.
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Affiliation(s)
- Milena Jaskólska
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - David W Adams
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Melanie Blokesch
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Station 19, EPFL-SV-UPBLO, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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11
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Liu S, Lu H, Zhang S, Shi Y, Chen Q. Phages against Pathogenic Bacterial Biofilms and Biofilm-Based Infections: A Review. Pharmaceutics 2022; 14:pharmaceutics14020427. [PMID: 35214158 PMCID: PMC8875263 DOI: 10.3390/pharmaceutics14020427] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 02/01/2023] Open
Abstract
Bacterial biofilms formed by pathogens are known to be hundreds of times more resistant to antimicrobial agents than planktonic cells, making it extremely difficult to cure biofilm-based infections despite the use of antibiotics, which poses a serious threat to human health. Therefore, there is an urgent need to develop promising alternative antimicrobial therapies to reduce the burden of drug-resistant bacterial infections caused by biofilms. As natural enemies of bacteria, bacteriophages (phages) have the advantages of high specificity, safety and non-toxicity, and possess great potential in the defense and removal of pathogenic bacterial biofilms, which are considered to be alternatives to treat bacterial diseases. This work mainly reviews the composition, structure and formation process of bacterial biofilms, briefly discusses the interaction between phages and biofilms, and summarizes several strategies based on phages and their derivatives against biofilms and drug-resistant bacterial infections caused by biofilms, serving the purpose of developing novel, safe and effective treatment methods against biofilm-based infections and promoting the application of phages in maintaining human health.
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Affiliation(s)
| | | | | | - Ying Shi
- Correspondence: (Y.S.); (Q.C.); Tel.: +86-139-6717-1522 (Y.S.)
| | - Qihe Chen
- Correspondence: (Y.S.); (Q.C.); Tel.: +86-139-6717-1522 (Y.S.)
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12
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Sato JL, Fonseca DLDH, Galhardo RS. rumAB genes from SXT/R391 ICEs confer UV-induced mutability to Proteus mirabilis hosts and improve conjugation after UV irradiation. DNA Repair (Amst) 2022; 112:103297. [DOI: 10.1016/j.dnarep.2022.103297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 02/04/2022] [Accepted: 02/07/2022] [Indexed: 01/08/2023]
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13
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Olesen AK, Pinilla-Redondo R, Hansen MF, Russel J, Dechesne A, Smets BF, Madsen JS, Nesme J, Sørensen SJ. IncHI1A plasmids potentially facilitate a horizontal flow of antibiotic resistance genes to pathogens in microbial communities of urban residential sewage. Mol Ecol 2022; 31:1595-1608. [PMID: 35014098 DOI: 10.1111/mec.16346] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/29/2021] [Accepted: 01/06/2022] [Indexed: 11/28/2022]
Abstract
Horizontal gene transfer via plasmids is important for the dissemination of antibiotic resistance genes among medically relevant pathogens. Specifically, the transfer of IncHI1A plasmids is believed to facilitate the spread of antibiotic resistance genes, such as carbapenemases, within the clinically important family Enterobacteriaceae. The microbial community of urban wastewater treatment plants has been shown to be highly permissive towards conjugal transfer of IncP1 plasmids. Here, we tracked the transfer of the P1 plasmid pB10 and the clinically relevant HI1A plasmid R27 in the microbial communities present in urban residential sewage entering full-scale wastewater treatment plants. We found that both plasmids readily transferred to these communities and that strains in the sewage were able to further disseminate them. Furthermore, that R27 has a broad potential host range, but a low host divergence. Interestingly, although the majority of R27 transfer events were to members of Enterobacteriaceae, we found a subset of transfer to other families, even other phyla. Indicating, that HI1A plasmids facilitate horizontal gene transfer both within Enterobacteriaceae, but also across families of especially Gammaproteobacteria, such as Moraxellaceae, Pseudomonadaceae and Shewanellaceae. pB10 displayed a similar potential host range as R27. In contrast to R27, pB10 had a high host divergence. By culture enrichment of the transconjugant communities, we show that sewage strains of Enterobacteriaceae and Aeromonadaceae can stably maintain R27 and pB10, respectively. Our results suggest that dissemination in the urban residual water system of HI1A plasmids may result in an accelerated acquisition of antibiotic resistance genes among pathogens.
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Affiliation(s)
- Asmus K Olesen
- Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | | | - Mads F Hansen
- Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jakob Russel
- Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Arnaud Dechesne
- Department of Environmental Engineering, Technical University of Denmark, 2800, Kgs Lyngby, Denmark
| | - Barth F Smets
- Department of Environmental Engineering, Technical University of Denmark, 2800, Kgs Lyngby, Denmark
| | - Jonas S Madsen
- Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Joseph Nesme
- Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Søren J Sørensen
- Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
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14
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Shen Z, Tang CM, Liu GY. Towards a better understanding of antimicrobial resistance dissemination: what can be learnt from studying model conjugative plasmids? Mil Med Res 2022; 9:3. [PMID: 35012680 PMCID: PMC8744291 DOI: 10.1186/s40779-021-00362-z] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/26/2021] [Indexed: 12/12/2022] Open
Abstract
Bacteria can evolve rapidly by acquiring new traits such as virulence, metabolic properties, and most importantly, antimicrobial resistance, through horizontal gene transfer (HGT). Multidrug resistance in bacteria, especially in Gram-negative organisms, has become a global public health threat often through the spread of mobile genetic elements. Conjugation represents a major form of HGT and involves the transfer of DNA from a donor bacterium to a recipient by direct contact. Conjugative plasmids, a major vehicle for the dissemination of antimicrobial resistance, are selfish elements capable of mediating their own transmission through conjugation. To spread to and survive in a new bacterial host, conjugative plasmids have evolved mechanisms to circumvent both host defense systems and compete with co-resident plasmids. Such mechanisms have mostly been studied in model plasmids such as the F plasmid, rather than in conjugative plasmids that confer antimicrobial resistance (AMR) in important human pathogens. A better understanding of these mechanisms is crucial for predicting the flow of antimicrobial resistance-conferring conjugative plasmids among bacterial populations and guiding the rational design of strategies to halt the spread of antimicrobial resistance. Here, we review mechanisms employed by conjugative plasmids that promote their transmission and establishment in Gram-negative bacteria, by following the life cycle of conjugative plasmids.
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Affiliation(s)
- Zhen Shen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK.,Department of Laboratory Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Guang-Yu Liu
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK.
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15
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Establishment Genes Present on pLS20 Family of Conjugative Plasmids Are Regulated in Two Different Ways. Microorganisms 2021; 9:microorganisms9122465. [PMID: 34946067 PMCID: PMC8708921 DOI: 10.3390/microorganisms9122465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 11/16/2022] Open
Abstract
During conjugation, a conjugative DNA element is transferred from a donor to a recipient cell via a connecting channel. Conjugation has clinical relevance because it is the major route for spreading antibiotic resistance and virulence genes. The conjugation process can be divided into different steps. The initial steps carried out in the donor cell culminate in the transfer of a single DNA strand (ssDNA) of the conjugative element into the recipient cell. However, stable settlement of the conjugative element in the new host requires at least two additional events: conversion of the transferred ssDNA into double-stranded DNA and inhibition of the hosts' defence mechanisms to prevent degradation of the transferred DNA. The genes involved in this late step are historically referred to as establishment genes. The defence mechanisms of the host must be inactivated rapidly and-importantly-transiently, because prolonged inactivation would make the cell vulnerable to the attack of other foreign DNA, such as those of phages. Therefore, expression of the establishment genes in the recipient cell has to be rapid but transient. Here, we studied regulation of the establishment genes present on the four clades of the pLS20 family of conjugative plasmids harboured by different Bacillus species. Evidence is presented that two fundamentally different mechanisms regulate the establishment genes present on these plasmids. Identification of the regulatory sequences were critical in revealing the establishment regulons. Remarkably, whereas the conjugation genes involved in the early steps of the conjugation process are conserved and are located in a single large operon, the establishment genes are highly variable and organised in multiple operons. We propose that the mosaical distribution of establishment genes in multiple operons is directly related to the variability of defence genes encoded by the host bacterial chromosomes.
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16
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Forsberg KJ, Schmidtke DT, Werther R, Uribe RV, Hausman D, Sommer MOA, Stoddard BL, Kaiser BK, Malik HS. The novel anti-CRISPR AcrIIA22 relieves DNA torsion in target plasmids and impairs SpyCas9 activity. PLoS Biol 2021; 19:e3001428. [PMID: 34644300 PMCID: PMC8545432 DOI: 10.1371/journal.pbio.3001428] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 10/25/2021] [Accepted: 09/28/2021] [Indexed: 11/18/2022] Open
Abstract
To overcome CRISPR-Cas defense systems, many phages and mobile genetic elements (MGEs) encode CRISPR-Cas inhibitors called anti-CRISPRs (Acrs). Nearly all characterized Acrs directly bind Cas proteins to inactivate CRISPR immunity. Here, using functional metagenomic selection, we describe AcrIIA22, an unconventional Acr found in hypervariable genomic regions of clostridial bacteria and their prophages from human gut microbiomes. AcrIIA22 does not bind strongly to SpyCas9 but nonetheless potently inhibits its activity against plasmids. To gain insight into its mechanism, we obtained an X-ray crystal structure of AcrIIA22, which revealed homology to PC4-like nucleic acid-binding proteins. Based on mutational analyses and functional assays, we deduced that acrIIA22 encodes a DNA nickase that relieves torsional stress in supercoiled plasmids. This may render them less susceptible to SpyCas9, which uses free energy from negative supercoils to form stable R-loops. Modifying DNA topology may provide an additional route to CRISPR-Cas resistance in phages and MGEs.
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Affiliation(s)
- Kevin J. Forsberg
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
| | - Danica T. Schmidtke
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Rachel Werther
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Ruben V. Uribe
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Deanna Hausman
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Morten O. A. Sommer
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Barry L. Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Brett K. Kaiser
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Biology, Seattle University, Seattle, Washington, United States of America
| | - Harmit S. Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
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17
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Viral recombination systems limit CRISPR-Cas targeting through the generation of escape mutations. Cell Host Microbe 2021; 29:1482-1495.e12. [PMID: 34582782 DOI: 10.1016/j.chom.2021.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 06/24/2021] [Accepted: 09/02/2021] [Indexed: 12/26/2022]
Abstract
CRISPR-Cas systems provide immunity to bacteria by programing Cas nucleases with RNA guides that recognize and cleave infecting viral genomes. Bacteria and their viruses each encode recombination systems that could repair the cleaved viral DNA. However, it is unknown whether and how these systems can affect CRISPR immunity. Bacteriophage λ uses the Red system (gam-exo-bet) to promote recombination between related phages. Here, we show that λ Red also mediates evasion of CRISPR-Cas targeting. Gam inhibits the host E. coli RecBCD recombination system, allowing recombination and repair of the cleaved DNA by phage Exo-Beta, which promotes the generation of mutations within the CRISPR target sequence. Red recombination is strikingly more efficient than the host's RecBCD-RecA in the production of large numbers of phages that escape CRISPR targeting. These results reveal a role for Red-like systems in the protection of bacteriophages against sequence-specific nucleases, which may facilitate their spread across viral genomes.
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18
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Durand R, Deschênes F, Burrus V. Genomic islands targeting dusA in Vibrio species are distantly related to Salmonella Genomic Island 1 and mobilizable by IncC conjugative plasmids. PLoS Genet 2021; 17:e1009669. [PMID: 34415925 PMCID: PMC8409611 DOI: 10.1371/journal.pgen.1009669] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/01/2021] [Accepted: 08/09/2021] [Indexed: 11/18/2022] Open
Abstract
Salmonella Genomic Island 1 (SGI1) and its variants are significant contributors to the spread of antibiotic resistance among Gammaproteobacteria. All known SGI1 variants integrate at the 3’ end of trmE, a gene coding for a tRNA modification enzyme. SGI1 variants are mobilized specifically by conjugative plasmids of the incompatibility groups A and C (IncA and IncC). Using a comparative genomics approach based on genes conserved among members of the SGI1 group, we identified diverse integrative elements distantly related to SGI1 in several species of Vibrio, Aeromonas, Salmonella, Pokkaliibacter, and Escherichia. Unlike SGI1, these elements target two alternative chromosomal loci, the 5’ end of dusA and the 3’ end of yicC. Although they share many features with SGI1, they lack antibiotic resistance genes and carry alternative integration/excision modules. Functional characterization of IMEVchUSA3, a dusA-specific integrative element, revealed promoters that respond to AcaCD, the master activator of IncC plasmid transfer genes. Quantitative PCR and mating assays confirmed that IMEVchUSA3 excises from the chromosome and is mobilized by an IncC helper plasmid from Vibrio cholerae to Escherichia coli. IMEVchUSA3 encodes the AcaC homolog SgaC that associates with AcaD to form a hybrid activator complex AcaD/SgaC essential for its excision and mobilization. We identified the dusA-specific recombination directionality factor RdfN required for the integrase-mediated excision of dusA-specific elements from the chromosome. Like xis in SGI1, rdfN is under the control of an AcaCD-responsive promoter. Although the integration of IMEVchUSA3 disrupts dusA, it provides a new promoter sequence and restores the reading frame of dusA for proper expression of the tRNA-dihydrouridine synthase A. Phylogenetic analysis of the conserved proteins encoded by SGI1-like elements targeting dusA, yicC, and trmE gives a fresh perspective on the possible origin of SGI1 and its variants. We identified integrative elements distantly related to Salmonella Genomic Island 1 (SGI1), a key vector of antibiotic resistance genes in Gammaproteobacteria. SGI1 and its variants reside at the 3’ end of trmE, share a large, highly conserved core of genes, and carry a complex integron that confers multidrug resistance phenotypes to their hosts. Unlike members of the SGI1 group, these novel genomic islands target the 5’ end dusA or the 3’ end of yicC, lack multidrug resistance genes, and seem much more diverse. We showed here that, like SGI1, these elements are mobilized by conjugative plasmids of the IncC group. Based on comparative genomics and functional analyses, we propose a hypothetical model of the evolution of SGI1 and its siblings from the progenitor of IncA and IncC conjugative plasmids via an intermediate dusA-specific integrative element through gene losses and gain of alternative integration/excision modules.
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Affiliation(s)
- Romain Durand
- Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Florence Deschênes
- Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Vincent Burrus
- Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
- * E-mail:
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19
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Zakharova K, Caldwell BJ, Ta S, Wheat CT, Bell CE. Mutational Analysis of Redβ Single Strand Annealing Protein: Roles of the 14 Lysine Residues in DNA Binding and Recombination In Vivo. Int J Mol Sci 2021; 22:ijms22147758. [PMID: 34299376 PMCID: PMC8303780 DOI: 10.3390/ijms22147758] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 01/05/2023] Open
Abstract
Redβ is a 261 amino acid protein from bacteriophage λ that promotes a single-strand annealing (SSA) reaction for repair of double-stranded DNA (dsDNA) breaks. While there is currently no high-resolution structure available for Redβ, models of its DNA binding domain (residues 1-188) have been proposed based on homology with human Rad52, and a crystal structure of its C-terminal domain (CTD, residues 193-261), which binds to λ exonuclease and E. coli single-stranded DNA binding protein (SSB), has been determined. To evaluate these models, the 14 lysine residues of Redβ were mutated to alanine, and the variants tested for recombination in vivo and DNA binding and annealing in vitro. Most of the lysines within the DNA binding domain, including K36, K61, K111, K132, K148, K154, and K172, were found to be critical for DNA binding in vitro and recombination in vivo. By contrast, none of the lysines within the CTD, including K214, K245, K251, K253, and K258 were required for DNA binding in vitro, but two, K214 and K253, were critical for recombination in vivo, likely due to their involvement in binding to SSB. K61 was identified as a residue that is critical for DNA annealing, but not for initial ssDNA binding, suggesting a role in binding to the second strand of DNA incorporated into the complex. The K148A variant, which has previously been shown to be defective in oligomer formation, had the lowest affinity for ssDNA, and was the only variant that was completely non-cooperative, suggesting that ssDNA binding is coupled to oligomerization.
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Affiliation(s)
- Katerina Zakharova
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA; (K.Z.); (B.J.C.); (S.T.); (C.T.W.)
| | - Brian J. Caldwell
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA; (K.Z.); (B.J.C.); (S.T.); (C.T.W.)
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Shalya Ta
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA; (K.Z.); (B.J.C.); (S.T.); (C.T.W.)
| | - Carter T. Wheat
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA; (K.Z.); (B.J.C.); (S.T.); (C.T.W.)
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Charles E. Bell
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA; (K.Z.); (B.J.C.); (S.T.); (C.T.W.)
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- Correspondence:
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20
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De R. Mobile Genetic Elements of Vibrio cholerae and the Evolution of Its Antimicrobial Resistance. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.691604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Vibrio cholerae (VC) is the causative agent of the severe dehydrating diarrheal disease cholera. The primary treatment for cholera is oral rehydration therapy (ORT). However, in case of moderate to severe dehydration, antibiotics are administered to reduce morbidity. Due to the emergence of multidrug resistant (MDR) strains of VC routinely used antibiotics fail to be effective in cholera patients. Antimicrobial resistance (AMR) is encoded in the genome of bacteria and is usually acquired from other organisms cohabiting in the environment or in the gut with which it interacts in the gut or environmental niche. The antimicrobial resistance genes (ARGs) are usually borne on mobile genetic elements (MGEs) like plasmids, transposons, integrons and SXT constin. Horizontal gene transfer (HGT) helps in the exchange of ARGs among bacteria leading to dissemination of AMR. In VC the acquisition and loss of AMR to many antibiotics have been found to be a dynamic process. This review describes the different AMR determinants and mechanisms of resistance that have been discovered in VC. These ARGs borne usually on MGEs have been recovered from isolates associated with past and present epidemics worldwide. These are responsible for resistance of VC to common antibiotics and are periodically lost and gained contributing to its genetic evolution. These resistance markers can be routinely used for AMR surveillance in VC. The review also presents a precise perspective on the importance of the gut microbiome in the emergence of MDR VC and concludes that the gut microbiome is a potential source of molecular markers and networks which can be manipulated for the interception of AMR in the future.
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21
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Neil K, Allard N, Rodrigue S. Molecular Mechanisms Influencing Bacterial Conjugation in the Intestinal Microbiota. Front Microbiol 2021; 12:673260. [PMID: 34149661 PMCID: PMC8213034 DOI: 10.3389/fmicb.2021.673260] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/10/2021] [Indexed: 12/26/2022] Open
Abstract
Bacterial conjugation is a widespread and particularly efficient strategy to horizontally disseminate genes in microbial populations. With a rich and dense population of microorganisms, the intestinal microbiota is often considered a fertile environment for conjugative transfer and a major reservoir of antibiotic resistance genes. In this mini-review, we summarize recent findings suggesting that few conjugative plasmid families present in Enterobacteriaceae transfer at high rates in the gut microbiota. We discuss the importance of mating pair stabilization as well as additional factors influencing DNA transfer efficiency and conjugative host range in this environment. Finally, we examine the potential repurposing of bacterial conjugation for microbiome editing.
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Affiliation(s)
- Kevin Neil
- Départment de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Nancy Allard
- Départment de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Sébastien Rodrigue
- Départment de Biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
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22
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Caldwell BJ, Norris A, Zakharova E, Smith CE, Wheat CT, Choudhary D, Sotomayor M, Wysocki VH, Bell CE. Oligomeric complexes formed by Redβ single strand annealing protein in its different DNA bound states. Nucleic Acids Res 2021; 49:3441-3460. [PMID: 33693865 PMCID: PMC8034648 DOI: 10.1093/nar/gkab125] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 02/09/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023] Open
Abstract
Redβ is a single strand annealing protein from bacteriophage λ that binds loosely to ssDNA, not at all to pre-formed dsDNA, but tightly to a duplex intermediate of annealing. As viewed by electron microscopy, Redβ forms oligomeric rings on ssDNA substrate, and helical filaments on the annealed duplex intermediate. However, it is not clear if these are the functional forms of the protein in vivo. We have used size-exclusion chromatography coupled with multi-angle light scattering, analytical ultracentrifugation and native mass spectrometry (nMS) to characterize the size of the oligomers formed by Redβ in its different DNA-bound states. The nMS data, which resolve species with the highest resolution, reveal that Redβ forms an oligomer of 12 subunits in the absence of DNA, complexes ranging from 4 to 14 subunits on 38-mer ssDNA, and a much more distinct and stable complex of 11 subunits on 38-mer annealed duplex. We also measure the concentration of Redβ in cells active for recombination and find it to range from 7 to 27 μM. Collectively, these data provide new insights into the dynamic nature of the complex on ssDNA, and the more stable and defined complex on annealed duplex.
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Affiliation(s)
- Brian J Caldwell
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Andrew Norris
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Ekaterina Zakharova
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Christopher E Smith
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Carter T Wheat
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Deepanshu Choudhary
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Marcos Sotomayor
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Vicki H Wysocki
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Charles E Bell
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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23
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Hancock SJ, Phan MD, Roberts LW, Vu TNM, Harris PNA, Beatson SA, Schembri MA. Characterization of DtrJ as an IncC plasmid conjugative DNA transfer component. Mol Microbiol 2021; 116:154-167. [PMID: 33567150 DOI: 10.1111/mmi.14697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 02/08/2021] [Indexed: 11/30/2022]
Abstract
Incompatibility group C (IncC) plasmids are large (50-400 kb), broad host range plasmids that drive the spread of genes conferring resistance to all classes of antibiotics, most notably the blaNDM gene that confers resistance to last-line carbapenems and the mcr-3 gene that confers resistance to colistin. Several recent studies have improved our understanding of the basic biological mechanisms driving the success of IncC, in particular the identification of multiple novel IncC conjugation genes by transposon directed insertion-site sequencing. Here, one of these genes, dtrJ, was examined in further detail. The dtrJ gene is located in the DNA transfer locus on the IncC backbone, and quantitative reverse-transcriptase PCR analysis revealed it is transcribed in the same operon as the DNA transfer genes traI and traD (encoding the relaxase and coupling protein, respectively) and activated by the AcaDC regulatory complex. We confirmed that DtrJ is not required for pilus biogenesis or mate pair formation. Instead, DtrJ localizes to the membrane, where it interacts with the coupling protein TraD and functions as an IncC DNA transfer protein. Overall, this work has defined the role of DtrJ in DNA transfer of IncC plasmids during conjugation.
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Affiliation(s)
- Steven J Hancock
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Minh-Duy Phan
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Leah W Roberts
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Thu Ngoc Minh Vu
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia.,College of Agriculture, Can Tho University, Can Tho City, Vietnam
| | - Patrick N A Harris
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia.,The University of Queensland Centre for Clinical Research, Brisbane, QLD, Australia
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
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24
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Beyond horizontal gene transfer: the role of plasmids in bacterial evolution. Nat Rev Microbiol 2021; 19:347-359. [PMID: 33469168 DOI: 10.1038/s41579-020-00497-1] [Citation(s) in RCA: 151] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2020] [Indexed: 12/27/2022]
Abstract
Plasmids have a key role in bacterial ecology and evolution because they mobilize accessory genes by horizontal gene transfer. However, recent studies have revealed that the evolutionary impact of plasmids goes above and beyond their being mere gene delivery platforms. Plasmids are usually kept at multiple copies per cell, producing islands of polyploidy in the bacterial genome. As a consequence, the evolution of plasmid-encoded genes is governed by a set of rules different from those affecting chromosomal genes, and these rules are shaped by unusual concepts in bacterial genetics, such as genetic dominance, heteroplasmy or segregational drift. In this Review, we discuss recent advances that underscore the importance of plasmids in bacterial ecology and evolution beyond horizontal gene transfer. We focus on new evidence that suggests that plasmids might accelerate bacterial evolution, mainly by promoting the evolution of plasmid-encoded genes, but also by enhancing the adaptation of their host chromosome. Finally, we integrate the most relevant theoretical and empirical studies providing a global understanding of the forces that govern plasmid-mediated evolution in bacteria.
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25
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Pinilla-Redondo R, Shehreen S, Marino ND, Fagerlund RD, Brown CM, Sørensen SJ, Fineran PC, Bondy-Denomy J. Discovery of multiple anti-CRISPRs highlights anti-defense gene clustering in mobile genetic elements. Nat Commun 2020; 11:5652. [PMID: 33159058 PMCID: PMC7648647 DOI: 10.1038/s41467-020-19415-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 10/06/2020] [Indexed: 12/14/2022] Open
Abstract
Many prokaryotes employ CRISPR-Cas systems to combat invading mobile genetic elements (MGEs). In response, some MGEs have developed strategies to bypass immunity, including anti-CRISPR (Acr) proteins; yet the diversity, distribution and spectrum of activity of this immune evasion strategy remain largely unknown. Here, we report the discovery of new Acrs by assaying candidate genes adjacent to a conserved Acr-associated (Aca) gene, aca5, against a panel of six type I systems: I-F (Pseudomonas, Pectobacterium, and Serratia), I-E (Pseudomonas and Serratia), and I-C (Pseudomonas). We uncover 11 type I-F and/or I-E anti-CRISPR genes encoded on chromosomal and extrachromosomal MGEs within Enterobacteriaceae and Pseudomonas, and an additional Aca (aca9). The acr genes not only associate with other acr genes, but also with genes encoding inhibitors of distinct bacterial defense systems. Thus, our findings highlight the potential exploitation of acr loci neighborhoods for the identification of previously undescribed anti-defense systems.
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Affiliation(s)
- Rafael Pinilla-Redondo
- Section of Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
- University College Copenhagen, Copenhagen, Denmark
| | - Saadlee Shehreen
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Nicole D Marino
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - Robert D Fagerlund
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
| | - Chris M Brown
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
| | - Søren J Sørensen
- Section of Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
- Genetics Otago, University of Otago, Dunedin, New Zealand.
- Bio-protection Research Centre, University of Otago, Dunedin, New Zealand.
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA.
- Quantitative Biosciences Institute, UCSF, San Francisco, CA, USA.
- Innovative Genomics Institute, Berkeley, CA, USA.
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Virolle C, Goldlust K, Djermoun S, Bigot S, Lesterlin C. Plasmid Transfer by Conjugation in Gram-Negative Bacteria: From the Cellular to the Community Level. Genes (Basel) 2020; 11:genes11111239. [PMID: 33105635 PMCID: PMC7690428 DOI: 10.3390/genes11111239] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/15/2020] [Accepted: 10/20/2020] [Indexed: 02/06/2023] Open
Abstract
Bacterial conjugation, also referred to as bacterial sex, is a major horizontal gene transfer mechanism through which DNA is transferred from a donor to a recipient bacterium by direct contact. Conjugation is universally conserved among bacteria and occurs in a wide range of environments (soil, plant surfaces, water, sewage, biofilms, and host-associated bacterial communities). Within these habitats, conjugation drives the rapid evolution and adaptation of bacterial strains by mediating the propagation of various metabolic properties, including symbiotic lifestyle, virulence, biofilm formation, resistance to heavy metals, and, most importantly, resistance to antibiotics. These properties make conjugation a fundamentally important process, and it is thus the focus of extensive study. Here, we review the key steps of plasmid transfer by conjugation in Gram-negative bacteria, by following the life cycle of the F factor during its transfer from the donor to the recipient cell. We also discuss our current knowledge of the extent and impact of conjugation within an environmentally and clinically relevant bacterial habitat, bacterial biofilms.
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