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Sun WS, Torrens G, Ter Beek J, Cava F, Berntsson RPA. Breaking barriers: pCF10 type 4 secretion system relies on a self-regulating muramidase to modulate the cell wall. mBio 2024:e0048824. [PMID: 38940556 DOI: 10.1128/mbio.00488-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 05/29/2024] [Indexed: 06/29/2024] Open
Abstract
Conjugative type 4 secretion systems (T4SSs) are the main driver for the spread of antibiotic resistance genes and virulence factors in bacteria. To deliver the DNA substrate to recipient cells, it must cross the cell envelopes of both donor and recipient bacteria. In the T4SS from the enterococcal conjugative plasmid pCF10, PrgK is known to be the active cell wall degrading enzyme. It has three predicted extracellular hydrolase domains: metallo-peptidase (LytM), soluble lytic transglycosylase (SLT), and cysteine, histidine-dependent amidohydrolases/peptidases (CHAP). Here, we report the structure of the LytM domain and show that its active site is degenerate and lacks the active site metal. Furthermore, we show that only the predicted SLT domain is functional in vitro and that it unexpectedly has a muramidase instead of a lytic transglycosylase activity. While we did not observe any peptidoglycan hydrolytic activity for the LytM or CHAP domain, we found that these domains downregulated the SLT muramidase activity. The CHAP domain was also found to be involved in PrgK dimer formation. Furthermore, we show that PrgK interacts with PrgL, which likely targets PrgK to the rest of the T4SS. The presented data provides important information for understanding the function of Gram-positive T4SSs.IMPORTANCEAntibiotic resistance is a large threat to human health and is getting more prevalent. One of the major contributors to the spread of antibiotic resistance among different bacteria is type 4 secretion systems (T4SS). However, mainly T4SSs from Gram-negative bacteria have been studied in detail. T4SSs from Gram-positive bacteria, which stand for more than half of all hospital-acquired infections, are much less understood. The significance of our research is in identifying the function and regulation of a cell wall hydrolase, a key component of the pCF10 T4SS from Enterococcus faecalis. This system is one of the best-studied Gram-positive T4SSs, and this added knowledge aids in our understanding of horizontal gene transfer in E. faecalis as well as other medically relevant Gram-positive bacteria.
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Affiliation(s)
- Wei-Sheng Sun
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine and Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Gabriel Torrens
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
| | - Josy Ter Beek
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine and Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Felipe Cava
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
| | - Ronnie P-A Berntsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine and Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
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2
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Sharma DK, Rajpurohit YS. Multitasking functions of bacterial extracellular DNA in biofilms. J Bacteriol 2024; 206:e0000624. [PMID: 38445859 PMCID: PMC11025335 DOI: 10.1128/jb.00006-24] [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: 03/07/2024] Open
Abstract
Bacterial biofilms are intricate ecosystems of microbial communities that adhere to various surfaces and are enveloped by an extracellular matrix composed of polymeric substances. Within the context of bacterial biofilms, extracellular DNA (eDNA) originates from cell lysis or is actively secreted, where it exerts a significant influence on the formation, stability, and resistance of biofilms to environmental stressors. The exploration of eDNA within bacterial biofilms holds paramount importance in research, with far-reaching implications for both human health and the environment. An enhanced understanding of the functions of eDNA in biofilm formation and antibiotic resistance could inspire the development of strategies to combat biofilm-related infections and improve the management of antibiotic resistance. This comprehensive review encapsulates the latest discoveries concerning eDNA, encompassing its origins, functions within bacterial biofilms, and significance in bacterial pathogenesis.
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Affiliation(s)
- Dhirendra Kumar Sharma
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
- Schools of Life Sciences, Homi Bhabha National Institute (DAE—Deemed University), Mumbai, India
| | - Yogendra Singh Rajpurohit
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
- Schools of Life Sciences, Homi Bhabha National Institute (DAE—Deemed University), Mumbai, India
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3
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Sun WS, Lassinantti L, Järvå M, Schmitt A, ter Beek J, Berntsson RPA. Structural foundation for the role of enterococcal PrgB in conjugation, biofilm formation, and virulence. eLife 2023; 12:RP84427. [PMID: 37860966 PMCID: PMC10588982 DOI: 10.7554/elife.84427] [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: 10/21/2023] Open
Abstract
Type 4 Secretion Systems are a main driver for the spread of antibiotic resistance genes and virulence factors in bacteria. In Gram-positives, these secretion systems often rely on surface adhesins to enhance cellular aggregation and mating-pair formation. One of the best studied adhesins is PrgB from the conjugative plasmid pCF10 of Enterococcus faecalis, which has been shown to play major roles in conjugation, biofilm formation, and importantly also in bacterial virulence. Since prgB orthologs exist on a large number of conjugative plasmids in various different species, this makes PrgB a model protein for this widespread virulence factor. After characterizing the polymer adhesin domain of PrgB previously, we here report the structure for almost the entire remainder of PrgB, which reveals that PrgB contains four immunoglobulin (Ig)-like domains. Based on this new insight, we re-evaluate previously studied variants and present new in vivo data where specific domains or conserved residues have been removed. For the first time, we can show a decoupling of cellular aggregation from biofilm formation and conjugation in prgB mutant phenotypes. Based on the presented data, we propose a new functional model to explain how PrgB mediates its different functions. We hypothesize that the Ig-like domains act as a rigid stalk that presents the polymer adhesin domain at the right distance from the cell wall.
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Affiliation(s)
- Wei-Sheng Sun
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
- Wallenberg Centre for Molecular Medicine, Umeå UniversityUmeåSweden
| | - Lena Lassinantti
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
| | - Michael Järvå
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
| | - Andreas Schmitt
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
| | - Josy ter Beek
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
- Wallenberg Centre for Molecular Medicine, Umeå UniversityUmeåSweden
| | - Ronnie P-A Berntsson
- Department of Medical Biochemistry and Biophysics, Umeå UniversityUmeåSweden
- Wallenberg Centre for Molecular Medicine, Umeå UniversityUmeåSweden
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Im EJ, Lee HHY, Kim M, Kim MK. Evaluation of Enterococcal Probiotic Usage and Review of Potential Health Benefits, Safety, and Risk of Antibiotic-Resistant Strain Emergence. Antibiotics (Basel) 2023; 12:1327. [PMID: 37627747 PMCID: PMC10451534 DOI: 10.3390/antibiotics12081327] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/11/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Enterococci are often used in probiotics but can also cause nosocomial infections. As such, enterococcal consumption may have beneficial health effects, but a thorough evaluation of virulence absence and risk of antibiotic resistance spread is needed at the strain level. This article reviewed ten online health product shopping websites in the US. On these websites, 23 probiotic products using enterococci were found across 12 companies. In addition, this article reviewed studies that demonstrated the probiotic potential of enterococcal consumption (e.g., gastrointestinal and respiratory disease, hyperlipidemia alleviation, as well as infection prevention). To investigate the safety aspects of enterococci, the present work examined studies evaluating virulence factors and antibiotic resistance. Furthermore, this article assessed research that explored these virulent factors, specifically in probiotics containing enterococci, as well as the potential transfer mechanism of their antibiotic resistance. Based on reviewed data, enterococcal probiotic consumption has been proven beneficial for conditions or symptoms of multiple diseases without any apparent adverse effects. However, due to the plasmid- or transposon-mediated gene transfer ability of enterococci, surveillance monitoring and further studies regarding enterococcal consumption are warranted. Future studies that identify enterococcal strains safe to use in probiotics without virulence factors and antibiotic resistance are imperative for evidence-based decisions by health organizations and government agencies.
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Affiliation(s)
- Eric Jeeho Im
- College of Arts and Sciences, Washington University, St. Louis, MO 63130, USA;
| | - Harry Hyun-Yup Lee
- School of Osteopathic Medicine, Campbell University, Lillington, NC 27546, USA
| | - Minzae Kim
- College of Arts and Sciences, Boston University, Boston, MA 02215, USA
| | - Myo-Kyoung Kim
- Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA 95211, USA
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5
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Barringer R, Parnell AE, Lafita A, Monzon V, Back CR, Madej M, Potempa J, Nobbs AH, Burston SG, Bateman A, Race PR. Domain shuffling of a highly mutable ligand-binding fold drives adhesin generation across the bacterial kingdom. Proteins 2023; 91:1007-1020. [PMID: 36912614 PMCID: PMC10952558 DOI: 10.1002/prot.26487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 03/14/2023]
Abstract
Bacterial fibrillar adhesins are specialized extracellular polypeptides that promote the attachment of bacteria to the surfaces of other cells or materials. Adhesin-mediated interactions are critical for the establishment and persistence of stable bacterial populations within diverse environmental niches and are important determinants of virulence. The fibronectin (Fn)-binding fibrillar adhesin CshA, and its paralogue CshB, play important roles in host colonization by the oral commensal and opportunistic pathogen Streptococcus gordonii. As paralogues are often catalysts for functional diversification, we have probed the early stages of structural and functional divergence in Csh proteins by determining the X-ray crystal structure of the CshB adhesive domain NR2 and characterizing its Fn-binding properties in vitro. Despite sharing a common fold, CshB_NR2 displays an ~1.7-fold reduction in Fn-binding affinity relative to CshA_NR2. This correlates with reduced electrostatic charge in the Fn-binding cleft. Complementary bioinformatic studies reveal that homologues of CshA/B_NR2 domains are widely distributed in both Gram-positive and Gram-negative bacteria, where they are found housed within functionally cryptic multi-domain polypeptides. Our findings are consistent with the classification of Csh adhesins and their relatives as members of the recently defined polymer adhesin domain (PAD) family of bacterial proteins.
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Affiliation(s)
- Rob Barringer
- School of BiochemistryUniversity of Bristol, University WalkBristolBS8 1TDUK
| | - Alice E. Parnell
- School of BiochemistryUniversity of Bristol, University WalkBristolBS8 1TDUK
- BrisSynBio Synthetic Biology Research CentreUniversity of Bristol, Life Sciences BuildingTyndall AvenueBristolBS8 1TQUK
| | - Aleix Lafita
- European Molecular Biology LaboratoryEuropean Bioinformatics Institute (EMBL‐EBI)Wellcome Genome CampusHinxtonCB10 1SDUK
| | - Vivian Monzon
- European Molecular Biology LaboratoryEuropean Bioinformatics Institute (EMBL‐EBI)Wellcome Genome CampusHinxtonCB10 1SDUK
| | - Catherine R. Back
- School of BiochemistryUniversity of Bristol, University WalkBristolBS8 1TDUK
- BrisSynBio Synthetic Biology Research CentreUniversity of Bristol, Life Sciences BuildingTyndall AvenueBristolBS8 1TQUK
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics, and BiotechnologyJagiellonian UniversityKrakowPoland
| | - Jan Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics, and BiotechnologyJagiellonian UniversityKrakowPoland
- Department of Oral Immunology and Infectious DiseasesUniversity of Louisville School of DentistryLouisvilleKentuckyUSA
| | - Angela H. Nobbs
- Bristol Dental School, University of BristolLower Maudlin StreetBristolBS1 2LYUK
| | - Steven G. Burston
- School of BiochemistryUniversity of Bristol, University WalkBristolBS8 1TDUK
| | - Alex Bateman
- European Molecular Biology LaboratoryEuropean Bioinformatics Institute (EMBL‐EBI)Wellcome Genome CampusHinxtonCB10 1SDUK
| | - Paul R. Race
- School of BiochemistryUniversity of Bristol, University WalkBristolBS8 1TDUK
- BrisSynBio Synthetic Biology Research CentreUniversity of Bristol, Life Sciences BuildingTyndall AvenueBristolBS8 1TQUK
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Han X, Wang J, Zhang J, Han B, Mei N, Fan R, Zhao J, Yao H, Yu X, Cai W. Digested extracellular DNA shortens the anodic startup of microbial electrolysis cell. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 875:162642. [PMID: 36894072 DOI: 10.1016/j.scitotenv.2023.162642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 02/21/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
While the multiple functions of extracellular DNA (exDNA) in biofilm formation and electron transfer have been extensively studied in pure culture, its role in mixed anodic biofilm was still unknown. In this study, we employed DNase I enzyme to digest exDNA, thereby investigating its role in anodic biofilm formation based on the performance of four microbial electrolysis cells (MECs) groups with different DNase I enzyme concentration (0, 0.05, 0.1, 0.5 mg/mL). The responding time to reach 60 % maximum current of treatment group with DNase I enzyme has been significantly reduced to 83 %-86 % of the blank group (t-test, p < 0.01), indicating the exDNA digestion could promote the biofilm formation at the early stage. The anodic coulombic efficiency was enhanced by 10.74- 54.42 % in treatment group (t-test, p < 0.05), which could be ascribed to the higher absolute abundance of exoelectrogens. The lower relative abundance of exoelectrogens indicated the DNase I enzyme addition was beneficial for the enrichment of extensive species rather than exoelectrogens. As the DNase I enzyme augments the fluorescence signal of exDNA distribution in the small molecular weight region, implying the short chain exDNA could contribute to the biomass enhancement via boosting the most species enrichment. Furthermore, the exDNA alteration improved the complexity of microbial network. Our findings provide a new insight into the role of exDNA in the extracellular matrix of anodic biofilms.
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Affiliation(s)
- Xiangyu Han
- School of Environment, Beijing Jiaotong University, Beijing 100044, China; Intelligent Environment Research Center, Beijing Jiaotong University, No. 1 Guanzhuang, Chaoyang District, Beijing 100080, China
| | - Jiaman Wang
- School of Engineering, Brown University, Providence, Rohde Island 02912, United States of America
| | - Jingjing Zhang
- School of Environment, Beijing Jiaotong University, Beijing 100044, China; Intelligent Environment Research Center, Beijing Jiaotong University, No. 1 Guanzhuang, Chaoyang District, Beijing 100080, China
| | - Baohong Han
- School of Environment, Beijing Jiaotong University, Beijing 100044, China; Intelligent Environment Research Center, Beijing Jiaotong University, No. 1 Guanzhuang, Chaoyang District, Beijing 100080, China
| | - Ning Mei
- School of Environment, Beijing Jiaotong University, Beijing 100044, China; Intelligent Environment Research Center, Beijing Jiaotong University, No. 1 Guanzhuang, Chaoyang District, Beijing 100080, China
| | - Runchuan Fan
- School of Environment, Beijing Jiaotong University, Beijing 100044, China
| | - Jing Zhao
- School of Environment, Beijing Jiaotong University, Beijing 100044, China; Intelligent Environment Research Center, Beijing Jiaotong University, No. 1 Guanzhuang, Chaoyang District, Beijing 100080, China
| | - Hong Yao
- School of Environment, Beijing Jiaotong University, Beijing 100044, China; Intelligent Environment Research Center, Beijing Jiaotong University, No. 1 Guanzhuang, Chaoyang District, Beijing 100080, China
| | - Xiaohua Yu
- School of Environment, Beijing Jiaotong University, Beijing 100044, China; Intelligent Environment Research Center, Beijing Jiaotong University, No. 1 Guanzhuang, Chaoyang District, Beijing 100080, China
| | - Weiwei Cai
- School of Environment, Beijing Jiaotong University, Beijing 100044, China; Intelligent Environment Research Center, Beijing Jiaotong University, No. 1 Guanzhuang, Chaoyang District, Beijing 100080, China.
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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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The Regulations of Essential WalRK Two-Component System on Enterococcus faecalis. J Clin Med 2023; 12:jcm12030767. [PMID: 36769415 PMCID: PMC9917794 DOI: 10.3390/jcm12030767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/04/2023] [Accepted: 01/10/2023] [Indexed: 01/20/2023] Open
Abstract
Enterococcus faecalis (E. faecalis) is a Gram-positive, facultative anaerobic bacterium that is highly adaptable to its environment. In humans, it can cause serious infections with biofilm formation. With increasing attention on its health threat, prevention and control of biofilm formation in E. faecalis have been observed. Many factors including polysaccharides as well as autolysis, proteases, and eDNA regulate biofilm formation. Those contributors are regulated by several important regulatory systems involving the two-component signal transduction system (TCS) for its adaptation to the environment. Highly conserved WalRK as one of 17 TCSs is the only essential TCS in E. faecalis. In addition to biofilm formation, various metabolisms, including cell wall construction, drug resistance, as well as interactions among regulatory systems and resistance to the host immune system, can be modulated by the WalRK system. Therefore, WalRK has been identified as a key target for E. faecalis infection control. In the present review, the regulation of WalRK on E. faecalis pathogenesis and associated therapeutic strategies are demonstrated.
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Yang Y, Yang X, Zhou H, Niu Y, Li J, Fu X, Wang S, Xue B, Li C, Zhao C, Zhang X, Shen Z, Wang J, Qiu Z. Bisphenols Promote the Pheromone-Responsive Plasmid-Mediated Conjugative Transfer of Antibiotic Resistance Genes in Enterococcus faecalis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17653-17662. [PMID: 36445841 DOI: 10.1021/acs.est.2c05349] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The enrichment and spread of antibiotic resistance genes (ARGs) induced by environmental chemical pollution further exacerbated the threat to human health and ecological safety. Several compounds are known to induce R plasmid-mediated conjugation through inducing reactive oxygen species (ROS), increasing cell membrane permeability, enhancing regulatory genes expression, and so forth. Up to now, there has been no substantial breakthrough in the studies of models and related mechanisms. Here, we established a new conjugation model using pheromone-responsive plasmid pCF10 and confirmed that five kinds of bisphenols (BPs) at environmentally relevant concentrations could significantly promote the conjugation of ARGs mediated by plasmid pCF10 in E. faecalis by up to 4.5-fold compared with untreated cells. Using qPCR, gene knockout and UHPLC, we explored the mechanisms behind this phenomenon using bisphenol A (BPA) as a model of BPs and demonstrated that BPA could upregulate the expression of pheromone, promote bacterial aggregation, and even directly activate conjugation as a pheromone instead of producing ROS and enhancing cell membrane permeability. Interestingly, the result of mathematical analysis showed that the pheromone effect of most BPs is more potent than that of synthetic pheromone cCF10. These findings provide new insight into the environmental behavior and biological effect of BPs and provided new method and theory to study on enrichment and spread of ARGs induced by environmental chemical pollution.
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Affiliation(s)
- Yutong Yang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Xiaobo Yang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Hongrui Zhou
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Yuanyuan Niu
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
- Shanghai Ocean University, Shanghai201306, China
| | - Jing Li
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
- Tianjin University of Traditional Chinese Medicine, Tianjin301617, China
| | - Xinyue Fu
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
- Shanghai Ocean University, Shanghai201306, China
| | - Shang Wang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Bin Xue
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Chenyu Li
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Chen Zhao
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Xi Zhang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Zhiqiang Shen
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Jingfeng Wang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Zhigang Qiu
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
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10
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Anti-Biofilm and Antibacterial Activities of Cycas media R. Br Secondary Metabolites: In Silico, In Vitro, and In Vivo Approaches. Antibiotics (Basel) 2022; 11:antibiotics11080993. [PMID: 35892383 PMCID: PMC9394325 DOI: 10.3390/antibiotics11080993] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/18/2022] [Accepted: 07/22/2022] [Indexed: 11/17/2022] Open
Abstract
Enterococcus species possess many virulence factors that have an essential role in exacerbating the infections caused by them. The current study aimed to evaluate the effect of the secondary metabolites ginkgetin (GINK) and sotetsuflavone (SOTE), isolated from Cycas media R. Br dichloromethane fraction, on Enterococcus faecalis (E. faecalis) isolates for the first time. The antibacterial and antivirulence activities of the isolated compounds were investigated using docking studies and in vitro by determination of the minimum inhibitory concentrations (MICs). Additionally, flow cytometry and scanning electron microscope (SEM) were utilized to assess the effect of SOTE on the tested bacteria. Moreover, crystal violet assay and qRT-PCR were used to test the effect of SOTE on the biofilm-forming ability of E. faecalis isolates. In addition, a systemic infection model was utilized in vivo to investigate the antibacterial activity of SOTE. We found that both GINK and SOTE showed a good affinity for the five proteins enrolled in the virulence of E. faecalis, with SOTE being the highest, suggesting the possible mechanisms for the antivirulence activity of both ligands. In addition, SOTE exhibited a higher antibacterial activity than GINK, as the values of the MICs of SOTE were lower than those of GINK. Thus, we performed the in vitro and in vivo assays on SOTE. However, they did not exhibit any significant variations (p > 0.05) in the membrane depolarization of E. faecalis isolates. Moreover, as evaluated by SEM, SOTE caused distortion and deformation in the treated cells. Regarding its impact on the biofilm formation, it inhibited the biofilm-forming ability of the tested isolates, as determined by crystal violet assay and qRT-PCR. The in vivo experiment revealed that SOTE resulted in a reduction of the inflammation of the liver and spleen with an increase in the survival rate. SOTE also improved the liver-function tests and decreased tumor necrosis factor-alpha using immunostaining and the inflammation markers, interleukins (IL-1β and IL-6), using ELISA. Thus, we can conclude that SOTE could be a promising compound that should be investigated in future preclinical and clinical studies.
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11
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Kurushima J, Tomita H. Advances of genetic engineering in Streptococci and Enterococci. Microbiol Immunol 2022; 66:411-417. [PMID: 35703039 DOI: 10.1111/1348-0421.13015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/09/2022] [Accepted: 06/11/2022] [Indexed: 11/26/2022]
Abstract
In the post-genome era, reverse genetic engineering is an indispensable methodology for experimental molecular biology to provide a deeper understanding of the principal relationship between genomic features and biological phenotypes. Technically, genetic engineering is carried out through allele replacement of a target genomic locus with a designed nucleotide sequence, so called site-directed mutagenesis. To artificially manipulate allele replacement through homologous recombination, researchers have improved various methodologies that are optimized to the bacterial species of interest. Here, we review widely used genetic engineering technologies, particularly for streptococci and enterococci, and recent advances that enable more effective and flexible manipulation. The development of genetic engineering has been promoted by synthetic biology approaches based on basic biology knowledge of horizontal gene transfer systems, such as natural conjugative transfer, natural transformation, and the CRISPR/Cas system. Therefore, this review also describes basic insights into molecular biology that underlie improvements in genetic engineering technology. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jun Kurushima
- Department of Bacteriology, Gunma University Graduate School of Medicine, 3-39-22, Showa-machi, Maebashi-shi, Gunma, 371-8511, Japan
| | - Haruyoshi Tomita
- Department of Bacteriology, Gunma University Graduate School of Medicine, 3-39-22, Showa-machi, Maebashi-shi, Gunma, 371-8511, Japan.,Laboratory of Bacterial Drug Resistance, Gunma University Graduate School of Medicine, 3-39-22, Showa-machi, Maebashi-shi, Gunma, 371-8511, Japan
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12
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Jäger F, Lamy A, Sun WS, Guerini N, Berntsson RPA. Structure of the enterococcal T4SS protein PrgL reveals unique dimerization interface in the VirB8 protein family. Structure 2022; 30:876-885.e5. [DOI: 10.1016/j.str.2022.03.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/20/2022] [Accepted: 03/22/2022] [Indexed: 12/22/2022]
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13
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Serrage HJ, Jepson MA, Rostami N, Jakubovics NS, Nobbs AH. Understanding the Matrix: The Role of Extracellular DNA in Oral Biofilms. FRONTIERS IN ORAL HEALTH 2022; 2:640129. [PMID: 35047995 PMCID: PMC8757797 DOI: 10.3389/froh.2021.640129] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 02/09/2021] [Indexed: 12/13/2022] Open
Abstract
Dental plaque is the key etiological agent in caries formation and the development of the prevalent chronic oral inflammatory disease, periodontitis. The dental plaque biofilm comprises a diverse range of microbial species encased within a rich extracellular matrix, of which extracellular DNA (eDNA) has been identified as an important component. The molecular mechanisms of eDNA release and the structure of eDNA have yet to be fully characterized. Nonetheless, key functions that have been proposed for eDNA include maintaining biofilm structural integrity, initiating adhesion to dental surfaces, acting as a nutrient source, and facilitating horizontal gene transfer. Thus, eDNA is a potential therapeutic target for the management of oral disease–associated biofilm. This review aims to summarize advances in the understanding of the mechanisms of eDNA release from oral microorganisms and in the methods of eDNA detection and quantification within oral biofilms.
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Affiliation(s)
- Hannah J Serrage
- Bristol Dental School, University of Bristol, Bristol, United Kingdom
| | - Mark A Jepson
- Wolfson Bioimaging Facility, University of Bristol, Bristol, United Kingdom
| | - Nadia Rostami
- School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nicholas S Jakubovics
- School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Angela H Nobbs
- Bristol Dental School, University of Bristol, Bristol, United Kingdom
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14
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Conwell M, Dooley J, Naughton PJ. Enterococcal biofilm - a nidus for antibiotic resistance transfer? J Appl Microbiol 2022; 132:3444-3460. [PMID: 34990042 PMCID: PMC9306868 DOI: 10.1111/jam.15441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 08/03/2021] [Accepted: 01/03/2022] [Indexed: 11/30/2022]
Abstract
Enterococci, important agents of hospital acquired infection, are listed on the WHO list of multi-drug resistant pathogens commonly encountered in hospital acquired infections are now of increasing importance, due to the development of strains resistant to multiple antibiotics. Enterococci are also important microorganisms in the environment and their presence is frequently used as an indicator of faecal pollution. Their success is related to their ability to survive within a broad range of habitats and the ease by which they acquire mobile genetic elements, including plasmids, from other bacteria. The enterococci are frequently present within a bacterial biofilm which provides stability and protection to the bacterial population along with an opportunity for a variety of bacterial interactions. Enterococci can accept extrachromosomal DNA both from within its own species and from other bacterial species and this is enhanced by the proximity of the donor and recipient strains. It is this exchange of genetic material that makes the role of biofilm such an important aspect of the success of enterococci. There remain many questions regarding the most suitable model systems to study enterococci in biofilm and regarding the transfer of genetic material including antibiotic resistance in these biofilms. This review focuses on some important aspects of biofilm in the context of horizontal gene transfer (HGT) in enterococci.
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Affiliation(s)
- M Conwell
- The Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA
| | - Jsg Dooley
- The Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA
| | - P J Naughton
- The Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA
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15
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Ferchichi M, Sebei K, Boukerb AM, Karray-Bouraoui N, Chevalier S, Feuilloley MGJ, Connil N, Zommiti M. Enterococcus spp.: Is It a Bad Choice for a Good Use-A Conundrum to Solve? Microorganisms 2021; 9:2222. [PMID: 34835352 PMCID: PMC8622268 DOI: 10.3390/microorganisms9112222] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 12/12/2022] Open
Abstract
Since antiquity, the ubiquitous lactic acid bacteria (LAB) Enterococci, which are just as predominant in both human and animal intestinal commensal flora, have been used (and still are) as probiotics in food and feed production. Their qualities encounter several hurdles, particularly in terms of the array of virulence determinants, reflecting a notorious reputation that nearly prevents their use as probiotics. Additionally, representatives of the Enterococcus spp. genus showed intrinsic resistance to several antimicrobial agents, and flexibility to acquire resistance determinants encoded on a broad array of conjugative plasmids, transposons, and bacteriophages. The presence of such pathogenic aspects among some species represents a critical barrier compromising their use as probiotics in food. Thus, the genus neither has Generally Recognized as Safe (GRAS) status nor has it been included in the Qualified Presumption of Safety (QPS) list implying drastic legislation towards these microorganisms. To date, the knowledge of the virulence factors and the genetic structure of foodborne enterococcal strains is rather limited. Although enterococcal infections originating from food have never been reported, the consumption of food carrying virulence enterococci seems to be a risky path of transfer, and hence, it renders them poor choices as probiotics. Auspiciously, enterococcal virulence factors seem to be strain specific suggesting that clinical isolates carry much more determinants that food isolates. The latter remain widely susceptible to clinically relevant antibiotics and subsequently, have a lower potential for pathogenicity. In terms of the ideal enterococcal candidate, selected strains deemed for use in foods should not possess any virulence genes and should be susceptible to clinically relevant antibiotics. Overall, implementation of an appropriate risk/benefit analysis, in addition to the case-by-case assessment, the establishment of a strain's innocuity, and consideration for relevant guidelines, legislation, and regulatory aspects surrounding functional food development seem to be the crucial elements for industries, health-staff and consumers to accept enterococci, like other LAB, as important candidates for useful and beneficial applications in food industry and food biotechnology. The present review aims at shedding light on the world of hurdles and limitations that hampers the Enterococcus spp. genus and its representatives from being used or proposed for use as probiotics. The future of enterococci use as probiotics and legislation in this field are also discussed.
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Affiliation(s)
- Mounir Ferchichi
- Unité de Protéomique Fonctionnelle et Potentiel Nutraceutique de la Biodiversité de Tunisie, Institut Supérieur des Sciences Biologiques Appliquées de Tunis, Université de Tunis El Manar, Tunis 1006, Tunisia; (M.F.); (K.S.)
| | - Khaled Sebei
- Unité de Protéomique Fonctionnelle et Potentiel Nutraceutique de la Biodiversité de Tunisie, Institut Supérieur des Sciences Biologiques Appliquées de Tunis, Université de Tunis El Manar, Tunis 1006, Tunisia; (M.F.); (K.S.)
| | - Amine Mohamed Boukerb
- Laboratoire de Microbiologie, Signaux et Microenvironnement (LMSM) EA 4312, Université de Rouen Normandie, 27000 Evreux, France; (A.M.B.); (S.C.); (M.G.J.F.); (N.C.)
| | - Najoua Karray-Bouraoui
- Laboratoire de Productivité Végétale et Contraintes Abiotiques, LR18ES04, Faculté des Sciences de Tunis, Université Tunis El Manar, Tunis 2092, Tunisia;
| | - Sylvie Chevalier
- Laboratoire de Microbiologie, Signaux et Microenvironnement (LMSM) EA 4312, Université de Rouen Normandie, 27000 Evreux, France; (A.M.B.); (S.C.); (M.G.J.F.); (N.C.)
| | - Marc G. J. Feuilloley
- Laboratoire de Microbiologie, Signaux et Microenvironnement (LMSM) EA 4312, Université de Rouen Normandie, 27000 Evreux, France; (A.M.B.); (S.C.); (M.G.J.F.); (N.C.)
| | - Nathalie Connil
- Laboratoire de Microbiologie, Signaux et Microenvironnement (LMSM) EA 4312, Université de Rouen Normandie, 27000 Evreux, France; (A.M.B.); (S.C.); (M.G.J.F.); (N.C.)
| | - Mohamed Zommiti
- Laboratoire de Microbiologie, Signaux et Microenvironnement (LMSM) EA 4312, Université de Rouen Normandie, 27000 Evreux, France; (A.M.B.); (S.C.); (M.G.J.F.); (N.C.)
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16
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Extracellular DNA (eDNA). A Major Ubiquitous Element of the Bacterial Biofilm Architecture. Int J Mol Sci 2021; 22:ijms22169100. [PMID: 34445806 PMCID: PMC8396552 DOI: 10.3390/ijms22169100] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 12/22/2022] Open
Abstract
After the first ancient studies on microbial slime (the name by which the biofilm matrix was initially indicated), multitudes of studies on the morphology, composition and physiology of biofilms have arisen. The emergence of the role that biofilms play in the pathogenesis of recalcitrant and persistent clinical infections, such as periprosthetic orthopedic infections, has reinforced scientific interest. Extracellular DNA (eDNA) is a recently uncovered component that is proving to be almost omnipresent in the extracellular polymeric substance (EPS) of biofilm. This macromolecule is eliciting unprecedented consideration for the critical impact on the pathogenesis of chronic clinical infections. After a systematic review of the literature, an updated description of eDNA in biofilms is presented, with a special focus on the latest findings regarding its fundamental structural role and the contribution it makes to the complex architecture of bacterial biofilms through interactions with a variety of other molecular components of the biofilm matrix.
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17
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Jiang K, Humbert N, K K S, Rouzina I, Mely Y, Westerlund F. The HIV-1 nucleocapsid chaperone protein forms locally compacted globules on long double-stranded DNA. Nucleic Acids Res 2021; 49:4550-4563. [PMID: 33872352 PMCID: PMC8096146 DOI: 10.1093/nar/gkab236] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 03/09/2021] [Accepted: 03/22/2021] [Indexed: 01/14/2023] Open
Abstract
The nucleocapsid (NC) protein plays key roles in Human Immunodeficiency Virus 1 (HIV-1) replication, notably by condensing and protecting the viral RNA genome and by chaperoning its reverse transcription into double-stranded DNA (dsDNA). Recent findings suggest that integration of viral dsDNA into the host genome, and hence productive infection, is linked to a small subpopulation of viral complexes where reverse transcription was completed within the intact capsid. Therefore, the synthesized dsDNA has to be tightly compacted, most likely by NC, to prevent breaking of the capsid in these complexes. To investigate NC’s ability to compact viral dsDNA, we here characterize the compaction of single dsDNA molecules under unsaturated NC binding conditions using nanofluidic channels. Compaction is shown to result from accumulation of NC at one or few compaction sites, which leads to small dsDNA condensates. NC preferentially initiates compaction at flexible regions along the dsDNA, such as AT-rich regions and DNA ends. Upon further NC binding, these condensates develop into a globular state containing the whole dsDNA molecule. These findings support NC’s role in viral dsDNA compaction within the mature HIV-1 capsid and suggest a possible scenario for the gradual dsDNA decondensation upon capsid uncoating and NC loss.
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Affiliation(s)
- Kai Jiang
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE 412 96, Sweden
| | - Nicolas Humbert
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, Illkirch F 67401, France
| | - Sriram K K
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE 412 96, Sweden
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA
| | - Yves Mely
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, Illkirch F 67401, France
| | - Fredrik Westerlund
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE 412 96, Sweden
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18
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Gago-Córdoba C, Val-Calvo J, Abia D, Díaz-Talavera A, Miguel-Arribas A, Aguilar Suárez R, van Dijl JM, Wu LJ, Meijer WJJ. A Conserved Class II Type Thioester Domain-Containing Adhesin Is Required for Efficient Conjugation in Bacillus subtilis. mBio 2021; 12:e00104-21. [PMID: 33727345 PMCID: PMC8092201 DOI: 10.1128/mbio.00104-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/05/2021] [Indexed: 12/16/2022] Open
Abstract
Conjugation, the process by which a DNA element is transferred from a donor to a recipient cell, is the main horizontal gene transfer route responsible for the spread of antibiotic resistance and virulence genes. Contact between a donor and a recipient cell is a prerequisite for conjugation, because conjugative DNA is transferred into the recipient via a channel connecting the two cells. Conjugative elements encode proteins dedicated to facilitating the recognition and attachment to recipient cells, also known as mating pair formation. A subgroup of the conjugative elements is able to mediate efficient conjugation during planktonic growth, and mechanisms facilitating mating pair formation will be particularly important in these cases. Conjugative elements of Gram-negative bacteria encode conjugative pili, also known as sex pili, some of which are retractile. Far less is known about mechanisms that promote mating pair formation in Gram-positive bacteria. The conjugative plasmid pLS20 of the Gram-positive bacterium Bacillus subtilis allows efficient conjugation in liquid medium. Here, we report the identification of an adhesin gene in the pLS20 conjugation operon. The N-terminal region of the adhesin contains a class II type thioester domain (TED) that is essential for efficient conjugation, particularly in liquid medium. We show that TED-containing adhesins are widely conserved in Gram-positive bacteria, including pathogens where they often play crucial roles in pathogenesis. Our study is the first to demonstrate the involvement of a class II type TED-containing adhesin in conjugation.IMPORTANCE Bacterial resistance to antibiotics has become a serious health care problem. The spread of antibiotic resistance genes between bacteria of the same or different species is often mediated by a process named conjugation, where a donor cell transfers DNA to a recipient cell through a connecting channel. The first step in conjugation is recognition and attachment of the donor to a recipient cell. Little is known about this first step, particularly in Gram-positive bacteria. Here, we show that the conjugative plasmid pLS20 of Bacillus subtilis encodes an adhesin protein that is essential for effective conjugation. This adhesin protein has a structural organization similar to adhesins produced by other Gram-positive bacteria, including major pathogens, where the adhesins serve in attachment to host tissues during colonization and infection. Our findings may thus also open novel avenues to design drugs that inhibit the spread of antibiotic resistance by blocking the first recipient-attachment step in conjugation.
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Affiliation(s)
- César Gago-Córdoba
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma, Madrid, Spain
| | - Jorge Val-Calvo
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma, Madrid, Spain
| | - David Abia
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma, Madrid, Spain
| | - Alberto Díaz-Talavera
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma, Madrid, Spain
| | - Andrés Miguel-Arribas
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma, Madrid, Spain
| | - Rocío Aguilar Suárez
- University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jan Maarten van Dijl
- University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ling Juan Wu
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Wilfried J J Meijer
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma, Madrid, Spain
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19
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Järvå MA, Hirt H, Dunny GM, Berntsson RPA. Polymer Adhesin Domains in Gram-Positive Cell Surface Proteins. Front Microbiol 2020; 11:599899. [PMID: 33324381 PMCID: PMC7726212 DOI: 10.3389/fmicb.2020.599899] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/28/2020] [Indexed: 01/12/2023] Open
Abstract
Surface proteins in Gram-positive bacteria are often involved in biofilm formation, host-cell interactions, and surface attachment. Here we review a protein module found in surface proteins that are often encoded on various mobile genetic elements like conjugative plasmids. This module binds to different types of polymers like DNA, lipoteichoic acid and glucans, and is here termed polymer adhesin domain. We analyze all proteins that contain a polymer adhesin domain and classify the proteins into distinct classes based on phylogenetic and protein domain analysis. Protein function and ligand binding show class specificity, information that will be useful in determining the function of the large number of so far uncharacterized proteins containing a polymer adhesin domain.
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Affiliation(s)
- Michael A Järvå
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Helmut Hirt
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Gary M Dunny
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Ronnie P-A Berntsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden.,Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
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20
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Manzer HS, Nobbs AH, Doran KS. The Multifaceted Nature of Streptococcal Antigen I/II Proteins in Colonization and Disease Pathogenesis. Front Microbiol 2020; 11:602305. [PMID: 33329493 PMCID: PMC7732690 DOI: 10.3389/fmicb.2020.602305] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 10/29/2020] [Indexed: 12/22/2022] Open
Abstract
Streptococci are Gram-positive bacteria that belong to the natural microbiota of humans and animals. Certain streptococcal species are known as opportunistic pathogens with the potential to cause severe invasive disease. Antigen I/II (AgI/II) family proteins are sortase anchored cell surface adhesins that are nearly ubiquitous across streptococci and contribute to many streptococcal diseases, including dental caries, respiratory tract infections, and meningitis. They appear to be multifunctional adhesins with affinities to various host substrata, acting to mediate attachment to host surfaces and stimulate immune responses from the colonized host. Here we will review the literature including recent work that has demonstrated the multifaceted nature of AgI/II family proteins, focusing on their overlapping and distinct functions and their important contribution to streptococcal colonization and disease.
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Affiliation(s)
- Haider S. Manzer
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Angela H. Nobbs
- Bristol Dental School, University of Bristol, Bristol, United Kingdom
| | - Kelly S. Doran
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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21
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Liu F, Jin P, Gong H, Sun Z, Du L, Wang D. Antibacterial and antibiofilm activities of thyme oil against foodborne multiple antibiotics-resistant Enterococcus faecalis. Poult Sci 2020; 99:5127-5136. [PMID: 32988551 PMCID: PMC7598324 DOI: 10.1016/j.psj.2020.06.067] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 06/16/2020] [Accepted: 06/17/2020] [Indexed: 01/09/2023] Open
Abstract
The inhibitory and bactericidal activities of thyme oil against the foodborne multiple antibiotics-resistant Enterococcus faecalis biofilm were evaluated in this study. Gas chromatography-mass spectrometry revealed that more than 70% of the composition of thyme oil is thymol. Crystal violet staining assay showed that 128 and 256 μg/mL thyme oil significantly inhibited the biofilm formation of E. faecalis. The cell adherence of E. faecalis, as shown by its swimming and swarming motilities, was reduced by thyme oil. The exopolysaccharide (EPS) quantification assay showed that thyme oil inhibited the EPS synthesis in E. faecalis biofilms. The 3D-view observations through confocal laser scanning and scanning electron microscopy suggested that cell adherence and biofilm thickness were decreased in thyme oil–treated biofilms. Quantitative real-time analyses showed that the transcription of ebp and epa gene clusters, which were related to cell mobility and EPS production, was inhibited by thyme oil. Thus, thyme oil effectively inhibited the biofilm formation of E. faecalis by affecting cell adherence and EPS synthesis. Furthermore, 2,048 and 4,096 μg/mL thyme oil can effectively inactivate E. faecalis population in the mature E. faecalis biofilms by 5.75 and 7.20 log CFU/mL, respectively, after 30 min of treatment. Thus, thyme oil at different concentrations can be used as an effective antibiofilm or germicidal agent to control E. faecalis biofilms.
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Affiliation(s)
- Fang Liu
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Panpan Jin
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Hansheng Gong
- School of Food Engineering, Ludong University, Yantai 264025, China
| | - Zhilan Sun
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Lihui Du
- College of Food Science and Engineering, Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China.
| | - Daoying Wang
- Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
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22
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Risks associated with enterococci as probiotics. Food Res Int 2019; 129:108788. [PMID: 32036912 DOI: 10.1016/j.foodres.2019.108788] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/07/2019] [Accepted: 10/29/2019] [Indexed: 01/01/2023]
Abstract
Probiotics are naturally occurring microorganisms that confer health benefits by altering host commensal microbiota, modulating immunity, enhancing intestinal barrier function, or altering pain perception. Enterococci are human and animal intestinal commensals that are used as probiotics and in food production. These microorganisms, however, express many virulence traits including cytolysin, proteases, aggregation substance, capsular polysaccharide, enterococcal surface protein, biofilm formation, extracellular superoxide, intestinal translocation, and resistance to innate immunity that can lead to serious hospital-acquired infections. In addition, enterococci are facile in acquiring antibiotic resistance genes to many clinically important antibiotics encoded on a wide variety of conjugative plasmids, transposons, and bacteriophages. The pathogenicity and disease burden caused by enterococci render them poor choices as probiotics. No large, randomized, placebo-controlled clinical trials have demonstrated the safety and efficacy of any enterococcal probiotic. As a result, no enterococcal probiotic has been approved by the United States Food and Drug Administration for the treatment, cure, or amelioration of human disease. In 2007, the European Food Safety Authority concluded that enterococci do not meet the standard for "Qualified Presumption of Safety". Enterococcal strains used or proposed for use as probiotics should be carefully screened for efficacy and safety.
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23
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Exploiting biofilm phenotypes for functional characterization of hypothetical genes in Enterococcus faecalis. NPJ Biofilms Microbiomes 2019; 5:23. [PMID: 31552139 PMCID: PMC6753144 DOI: 10.1038/s41522-019-0099-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/21/2019] [Indexed: 12/12/2022] Open
Abstract
Enterococcus faecalis is a commensal organism as well as an important nosocomial pathogen, and its infections are typically linked to biofilm formation. Nearly 25% of the E. faecalis OG1RF genome encodes hypothetical genes or genes of unknown function. Elucidating their function and how these gene products influence biofilm formation is critical for understanding E. faecalis biology. To identify uncharacterized early biofilm determinants, we performed a genetic screen using an arrayed transposon (Tn) library containing ~2000 mutants in hypothetical genes/intergenic regions and identified eight uncharacterized predicted protein-coding genes required for biofilm formation. We demonstrate that OG1RF_10435 encodes a phosphatase that modulates global protein expression and arginine catabolism and propose renaming this gene bph (biofilm phosphatase). We present a workflow for combining phenotype-driven experimental and computational evaluation of hypothetical gene products in E. faecalis, which can be used to study hypothetical genes required for biofilm formation and other phenotypes of diverse bacteria.
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24
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Abstract
The bacterial type IV secretion systems (T4SSs) are a functionally diverse superfamily of secretion systems found in many species of bacteria. Collectively, the T4SSs translocate DNA and monomeric and multimeric protein substrates to bacterial and eukaryotic cell types. T4SSs are composed of two large subfamilies, the conjugation machines and the effector translocators that transmit their cargoes through establishment of direct donor-target cell contacts, and a third small subfamily capable of importing or exporting substrates from or to the milieu. This review summarizes recent mechanistic and structural findings that are shedding new light on how T4SSs have evolved such functional diversity. Translocation signals are now known to be located C terminally or embedded internally in structural folds; these signals in combination with substrate-associated adaptor proteins mediate the docking of specific substrate repertoires to cognate VirD4-like receptors. For the Legionella pneumophila Dot/Icm system, recent work has elucidated the structural basis for adaptor-dependent substrate loading onto the VirD4-like DotL receptor. Advances in definition of T4SS machine structures now allow for detailed comparisons of nanomachines closely related to the Agrobacterium tumefaciens VirB/VirD4 T4SS with those more distantly related, e.g., the Dot/Icm and Helicobacter pylori Cag T4SSs. Finally, it is increasingly evident that T4SSs have evolved a variety of mechanisms dependent on elaboration of conjugative pili, membrane tubes, or surface adhesins to establish productive contacts with target cells. T4SSs thus have evolved extreme functional diversity through a plethora of adaptations impacting substrate selection, machine architecture, and target cell binding.
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25
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Kohler V, Keller W, Grohmann E. Enterococcus adhesin PrgB facilitates type IV secretion by condensation of extracellular DNA. Mol Microbiol 2018; 109:263-267. [PMID: 29873122 DOI: 10.1111/mmi.13994] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2018] [Indexed: 12/15/2022]
Abstract
Conjugative type IV secretion systems (T4SSs) are multi-protein complexes in Gram-negative and Gram-positive (G+) bacteria, responsible for spreading antibiotic resistances and virulence factors among different species. Compared to Gram-negative bacteria, which establish close contacts for conjugative transfer via sex pili, G+ T4SSs are suggested to employ surface adhesins instead. One example is pCF10, an enterococcal conjugative sex-pheromone responsive plasmid with a narrow host range, thus disseminating genetic information only among closely related species. This MicroCommentary is dedicated to the crystal structure of the pCF10-encoded adhesion domain of PrgB presented by Schmitt et al. The authors show in their work that this adhesion domain is responsible for biofilm formation, tight binding and condensation of extracellular DNA (eDNA) and conjugative transfer of pCF10. A sophisticated two-step mechanism for highly efficient conjugative transfer is postulated, including the formation of PrgB-mediated long-range intercellular contacts by binding and establishment of shorter-range contacts via condensation of eDNA. PrgB binding to lipoteichoic acid on the recipient cell surface stabilizes junctions between the mating partners. The major findings by Schmitt et al. will be brought into a broader context and potential medical applications targeting eDNA as essential component in biofilm formation and conjugation will be discussed.
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Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, BioTechMed, University of Graz, Graz, Austria
| | - Walter Keller
- Institute of Molecular Biosciences, BioTechMed, University of Graz, Graz, Austria
| | - Elisabeth Grohmann
- Life Sciences and Technology, Beuth University of Applied Sciences, Berlin, Germany
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