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Alav I, Buckner MMC. Non-antibiotic compounds associated with humans and the environment can promote horizontal transfer of antimicrobial resistance genes. Crit Rev Microbiol 2023:1-18. [PMID: 37462915 DOI: 10.1080/1040841x.2023.2233603] [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: 03/08/2023] [Revised: 05/23/2023] [Accepted: 06/30/2023] [Indexed: 02/15/2024]
Abstract
Horizontal gene transfer plays a key role in the global dissemination of antimicrobial resistance (AMR). AMR genes are often carried on self-transmissible plasmids, which are shared amongst bacteria primarily by conjugation. Antibiotic use has been a well-established driver of the emergence and spread of AMR. However, the impact of commonly used non-antibiotic compounds and environmental pollutants on AMR spread has been largely overlooked. Recent studies found common prescription and over-the-counter drugs, artificial sweeteners, food preservatives, and environmental pollutants, can increase the conjugative transfer of AMR plasmids. The potential mechanisms by which these compounds promote plasmid transmission include increased membrane permeability, upregulation of plasmid transfer genes, formation of reactive oxygen species, and SOS response gene induction. Many questions remain around the impact of most non-antibiotic compounds on AMR plasmid conjugation in clinical isolates and the long-term impact on AMR dissemination. By elucidating the role of routinely used pharmaceuticals, food additives, and pollutants in the dissemination of AMR, action can be taken to mitigate their impact by closely monitoring use and disposal. This review will discuss recent progress on understanding the influence of non-antibiotic compounds on plasmid transmission, the mechanisms by which they promote transfer, and the level of risk they pose.
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Affiliation(s)
- Ilyas Alav
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Michelle M C Buckner
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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2
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Fromm K, Boegli A, Ortelli M, Wagner A, Bohn E, Malmsheimer S, Wagner S, Dehio C. Bartonella taylorii: A Model Organism for Studying Bartonella Infection in vitro and in vivo. Front Microbiol 2022; 13:913434. [PMID: 35910598 PMCID: PMC9336547 DOI: 10.3389/fmicb.2022.913434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/05/2022] [Indexed: 11/13/2022] Open
Abstract
Bartonella spp. are Gram-negative facultative intracellular pathogens that infect diverse mammals and cause a long-lasting intra-erythrocytic bacteremia in their natural host. These bacteria translocate Bartonella effector proteins (Beps) into host cells via their VirB/VirD4 type 4 secretion system (T4SS) in order to subvert host cellular functions, thereby leading to the downregulation of innate immune responses. Most studies on the functional analysis of the VirB/VirD4 T4SS and the Beps were performed with the major zoonotic pathogen Bartonella henselae for which efficient in vitro infection protocols have been established. However, its natural host, the cat, is unsuitable as an experimental infection model. In vivo studies were mostly confined to rodent models using rodent-specific Bartonella species, while the in vitro infection protocols devised for B. henselae are not transferable for those pathogens. The disparities of in vitro and in vivo studies in different species have hampered progress in our understanding of Bartonella pathogenesis. Here we describe the murine-specific strain Bartonella taylorii IBS296 as a new model organism facilitating the study of bacterial pathogenesis both in vitro in cell cultures and in vivo in laboratory mice. We implemented the split NanoLuc luciferase-based translocation assay to study BepD translocation through the VirB/VirD4 T4SS. We found increased effector-translocation into host cells if the bacteria were grown on tryptic soy agar (TSA) plates and experienced a temperature shift immediately before infection. The improved infectivity in vitro was correlating to an upregulation of the VirB/VirD4 T4SS. Using our adapted infection protocols, we showed BepD-dependent immunomodulatory phenotypes in vitro. In mice, the implemented growth conditions enabled infection by a massively reduced inoculum without having an impact on the course of the intra-erythrocytic bacteremia. The established model opens new avenues to study the role of the VirB/VirD4 T4SS and the translocated Bep effectors in vitro and in vivo.
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Affiliation(s)
- Katja Fromm
- Biozentrum, University of Basel, Basel, Switzerland
| | - Alexandra Boegli
- Department of Biochemistry, Faculty of Biology and Medicine, Université de Lausanne, Epalinges, Switzerland
| | | | | | - Erwin Bohn
- Institute of Medical Microbiology and Hygiene, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Silke Malmsheimer
- Section of Cellular and Molecular Microbiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Samuel Wagner
- Section of Cellular and Molecular Microbiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
- Excellence Cluster “Controlling Microbes to Fight Infections” (CMFI), Tübingen, Germany
- Partner-site Tübingen, German Center for Infection Research (DZIF), Tübingen, Germany
| | - Christoph Dehio
- Biozentrum, University of Basel, Basel, Switzerland
- *Correspondence: Christoph Dehio,
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Xiong X, Li B, Zhou Z, Gu G, Li M, Liu J, Jiao H. The VirB System Plays a Crucial Role in Brucella Intracellular Infection. Int J Mol Sci 2021; 22:ijms222413637. [PMID: 34948430 PMCID: PMC8707931 DOI: 10.3390/ijms222413637] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/09/2021] [Accepted: 12/15/2021] [Indexed: 01/18/2023] Open
Abstract
Brucellosis is a highly prevalent zoonotic disease caused by Brucella. Brucella spp. are gram-negative facultative intracellular parasitic bacteria. Its intracellular survival and replication depend on a functional virB system, an operon encoded by VirB1–VirB12. Type IV secretion system (T4SS) encoded by the virB operon is an important virulence factor of Brucella. It can subvert cellular pathway and induce host immune response by secreting effectors, which promotes Brucella replication in host cells and induce persistent infection. Therefore, this paper summarizes the function and significance of the VirB system, focusing on the structure of the VirB system where VirB T4SS mediates biogenesis of the endoplasmic reticulum (ER)-derived replicative Brucella-containing vacuole (rBCV), the effectors of T4SS and the cellular pathways it subverts, which will help better understand the pathogenic mechanism of Brucella and provide new ideas for clinical vaccine research and development.
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Affiliation(s)
- Xue Xiong
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Bowen Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Zhixiong Zhou
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Guojing Gu
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Mengjuan Li
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
| | - Jun Liu
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Yujinxiang Street 573, Changchun 130122, China
- Correspondence: (J.L.); (H.J.)
| | - Hanwei Jiao
- College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (X.X.); (B.L.); (Z.Z.); (G.G.); (M.L.)
- National Center of Technology Innovation for Pigs, Chongqing 402460, China
- Veterinary Scientific Engineering Research Center, Chongqing 402460, China
- Immunology Research Center, Medical Research Institute, Southwest University, Chongqing 402460, China
- Correspondence: (J.L.); (H.J.)
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Patterson LL, Byerly CD, McBride JW. Anaplasmataceae: Dichotomous Autophagic Interplay for Infection. Front Immunol 2021; 12:642771. [PMID: 33912170 PMCID: PMC8075259 DOI: 10.3389/fimmu.2021.642771] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/15/2021] [Indexed: 12/19/2022] Open
Abstract
Autophagy is a vital conserved degradative process that maintains cellular homeostasis by recycling or eliminating dysfunctional cellular organelles and proteins. More recently, autophagy has become a well-recognized host defense mechanism against intracellular pathogens through a process known as xenophagy. On the host-microbe battlefield many intracellular bacterial pathogens have developed the ability to subvert xenophagy to establish infection. Obligately intracellular bacterial pathogens of the Anaplasmataceae family, including Ehrlichia chaffeensis, Anaplasma phaogocytophilium and Orientia tsutsugamushi have developed a dichotomous strategy to exploit the host autophagic pathway to obtain nutrients while escaping lysosomal destruction for intracellular survival within the host cell. In this review, the recent findings regarding how these master manipulators engage and inhibit autophagy for infection are explored. Future investigation to understand mechanisms used by Anaplasmataceae to exploit autophagy may advance novel antimicrobial therapies and provide new insights into how intracellular microbes exploit autophagy to survive.
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Affiliation(s)
- LaNisha L Patterson
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Caitlan D Byerly
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Jere W McBride
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States.,Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, United States.,Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, United States.,Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
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5
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Possible drugs for the treatment of bacterial infections in the future: anti-virulence drugs. J Antibiot (Tokyo) 2020; 74:24-41. [PMID: 32647212 DOI: 10.1038/s41429-020-0344-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/26/2020] [Accepted: 05/29/2020] [Indexed: 12/19/2022]
Abstract
Antibiotic resistance is a global threat that should be urgently resolved. Finding a new antibiotic is one way, whereas the repression of the dissemination of virulent pathogenic bacteria is another. From this point of view, this paper summarizes first the mechanisms of conjugation and transformation, two important processes of horizontal gene transfer, and then discusses the approaches for disarming virulent pathogenic bacteria, that is, virulence factor inhibitors. In contrast to antibiotics, anti-virulence drugs do not impose a high selective pressure on a bacterial population, and repress the dissemination of antibiotic resistance and virulence genes. Disarmed virulence factors make virulent pathogens avirulent bacteria or pathobionts, so that we human will be able to coexist with these disarmed bacteria peacefully.
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6
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Heilers JH, Reiners J, Heller EM, Golzer A, Smits SHJ, van der Does C. DNA processing by the MOBH family relaxase TraI encoded within the gonococcal genetic island. Nucleic Acids Res 2019; 47:8136-8153. [PMID: 31276596 PMCID: PMC6736028 DOI: 10.1093/nar/gkz577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 06/18/2019] [Accepted: 06/26/2019] [Indexed: 11/26/2022] Open
Abstract
Relaxases of the MOBH family are often found on large plasmids, genetic islands and integrative conjugative elements. Many members of this family contain an N-terminal relaxase domain (TraI_2) followed by a disordered middle part and a C-terminal domain of unknown function (TraI_2_C). The TraI_2 domain contains two putative metal-binding motifs, an HD domain motif and an alternative 3H motif. TraI, encoded within the gonococcal genetic island of Neisseria gonorrhoeae, is the prototype of the MOBH family. SAXS experiments showed that TraI_2 and TraI_2_C form globular structures separated by an extended middle domain. The TraI_2 domain cleaves oriT-ssDNA in a site-specific Mn2+ or Co2+ dependent manner. The minimal oriT encompasses 50 nucleotides, requires an inverted repeat 3′ of the nic-site and several nucleotides around nic for efficient cleavage. Surprisingly, no stable covalent relaxase-DNA intermediate was observed. Mutagenesis of conserved tyrosines showed that cleavage was abolished in the Y212A mutant, whereas the Y212F and Y212H mutants retained residual activity. The HD and the alternative 3H motifs were essential for cleavage and the HD domain residues D162 and D267 for metal ion binding. We propose that the active site binds two metal ions, one in a high-affinity and one in a low-affinity site.
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Affiliation(s)
- Jan-Hendrik Heilers
- Institute for Biology II, Microbiology, Albert Ludwig University Freiburg, 79104 Freiburg, Germany
| | - Jens Reiners
- Biochemie I, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany.,Center for Structural Studies, Heinrich Heine University, 40225 Düsseldorf, Germany
| | | | - Annika Golzer
- Institute for Biology II, Microbiology, Albert Ludwig University Freiburg, 79104 Freiburg, Germany
| | - Sander H J Smits
- Biochemie I, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany.,Center for Structural Studies, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Chris van der Does
- Institute for Biology II, Microbiology, Albert Ludwig University Freiburg, 79104 Freiburg, Germany
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7
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Peñil-Celis A, Garcillán-Barcia MP. Crosstalk Between Type VI Secretion System and Mobile Genetic Elements. Front Mol Biosci 2019; 6:126. [PMID: 31799257 PMCID: PMC6863884 DOI: 10.3389/fmolb.2019.00126] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022] Open
Abstract
Many bacterial processes require cell-cell contacts. Such are the cases of bacterial conjugation, one of the main horizontal gene transfer mechanisms that physically spreads DNA, and the type VI secretion systems (T6SSs), which deploy antibacterial activity. Bacteria depend on conjugation to adapt to changing environments, while T6SS killing activity could pose a threat to mating partners. Here we review the experimental evidences of overlapping and interaction between the T6SSs, bacterial conjugation, and conjugative genetic elements.
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Affiliation(s)
- Arancha Peñil-Celis
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, Santander, Spain
| | - M Pilar Garcillán-Barcia
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, Santander, Spain
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8
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Buß M, Tegtmeyer N, Schnieder J, Dong X, Li J, Springer TA, Backert S, Niemann HH. Specific high affinity interaction of Helicobacter pylori CagL with integrin α V β 6 promotes type IV secretion of CagA into human cells. FEBS J 2019; 286:3980-3997. [PMID: 31197920 DOI: 10.1111/febs.14962] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 04/12/2019] [Accepted: 06/10/2019] [Indexed: 12/21/2022]
Abstract
CagL is an essential pilus surface component of the virulence-associated type IV secretion system (T4SS) employed by Helicobacter pylori to translocate the oncogenic effector protein CagA into human gastric epithelial cells. CagL contains an RGD motif and integrin α5 β1 is widely accepted as its host cell receptor. Here, we show that CagL binds integrin αV β6 with substantially higher affinity and that this interaction is functionally important. Cell surface expression of αV β6 on various cell lines correlated perfectly with cell adhesion to immobilized CagL and with binding of soluble CagL to cells. We found no such correlation for α5 β1 . The purified αV β6 ectodomain bound CagL with high affinity. This interaction was highly specific, as the affinity of CagL for other RGD-binding integrins was two to three orders of magnitude weaker. Mutation of either conserved leucine in the CagL RGDLXXL motif, a motif that generally confers specificity for integrin αV β6 and αV β8 , lowered the affinity of CagL for αV β6 . Stable expression of αV β6 in αV β6 -negative but α5 β1 -expressing human cells promoted two hallmarks of the functional H. pylori T4SS, namely translocation of CagA into host cells and induction of interleukin-8 secretion by host cells. These findings suggest that integrin αV β6 , although not essential for T4SS function, represents an important host cell receptor for CagL.
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Affiliation(s)
- Maren Buß
- Structural Biochemistry, Department of Chemistry, Bielefeld University, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
| | - Jennifer Schnieder
- Structural Biochemistry, Department of Chemistry, Bielefeld University, Germany
| | - Xianchi Dong
- Children's Hospital Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Jing Li
- Children's Hospital Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Timothy A Springer
- Children's Hospital Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
| | - Hartmut H Niemann
- Structural Biochemistry, Department of Chemistry, Bielefeld University, Germany
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9
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Wagner A, Tittes C, Dehio C. Versatility of the BID Domain: Conserved Function as Type-IV-Secretion-Signal and Secondarily Evolved Effector Functions Within Bartonella-Infected Host Cells. Front Microbiol 2019; 10:921. [PMID: 31130928 PMCID: PMC6509941 DOI: 10.3389/fmicb.2019.00921] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/11/2019] [Indexed: 11/13/2022] Open
Abstract
Bartonella spp. are facultative intracellular pathogens that infect a wide range of mammalian hosts including humans. In order to subvert cellular functions and the innate immune response of their hosts, these pathogens utilize a VirB/VirD4 type-IV-secretion (T4S) system to translocate Bartonella effector proteins (Beps) into host cells. Crucial for this process is the Bep intracellular delivery (BID) domain that together with a C-terminal stretch of positively charged residues constitutes a bipartite T4S signal. This function in T4S is evolutionarily conserved with BID domains present in bacterial toxins and relaxases. Strikingly, some BID domains of Beps have evolved secondary functions to modulate host cell and innate immune pathways in favor of Bartonella infection. For instance, BID domains mediate F-actin-dependent bacterial internalization, inhibition of apoptosis, or modulate cell migration. Recently, crystal structures of three BID domains from different Beps have been solved, revealing a conserved fold formed by a four-helix bundle topped with a hook. While the conserved BID domain fold might preserve its genuine role in T4S, the highly variable surfaces characteristic for BID domains may facilitate secondary functions. In this review, we summarize our current knowledge on evolutionary and structural traits as well as functional aspects of the BID domain with regard to T4S and pathogenesis.
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Affiliation(s)
| | - Colin Tittes
- Biozentrum, University of Basel, Basel, Switzerland
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Waksman G. From conjugation to T4S systems in Gram-negative bacteria: a mechanistic biology perspective. EMBO Rep 2019; 20:embr.201847012. [PMID: 30602585 PMCID: PMC6362355 DOI: 10.15252/embr.201847012] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/31/2018] [Accepted: 11/27/2018] [Indexed: 12/19/2022] Open
Abstract
Conjugation is the process by which bacteria exchange genetic materials in a unidirectional manner from a donor cell to a recipient cell. The discovery of conjugation signalled the dawn of genetics and molecular biology. In Gram-negative bacteria, the process of conjugation is mediated by a large membrane-embedded machinery termed "conjugative type IV secretion (T4S) system", a large injection nanomachine, which together with a DNA-processing machinery termed "the relaxosome" and a large extracellular tube termed "pilus" orchestrates directional DNA transfer. Here, the focus is on past and latest research in the field of conjugation and T4S systems in Gram-negative bacteria, with an emphasis on the various questions and debates that permeate the field from a mechanistic perspective.
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Affiliation(s)
- Gabriel Waksman
- Institute of Structural and Molecular Biology, UCL and Birkbeck, London, UK
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