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Berne C, Zappa S, Brun YV. eDNA-stimulated cell dispersion from Caulobacter crescentus biofilms upon oxygen limitation is dependent on a toxin-antitoxin system. eLife 2023; 12:80808. [PMID: 36475544 PMCID: PMC9851616 DOI: 10.7554/elife.80808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
In their natural environment, most bacteria preferentially live as complex surface-attached multicellular colonies called biofilms. Biofilms begin with a few cells adhering to a surface, where they multiply to form a mature colony. When conditions deteriorate, cells can leave the biofilm. This dispersion is thought to be an important process that modifies the overall biofilm architecture and that promotes colonization of new environments. In Caulobacter crescentus biofilms, extracellular DNA (eDNA) is released upon cell death and prevents newborn cells from joining the established biofilm. Thus, eDNA promotes the dispersal of newborn cells and the subsequent colonization of new environments. These observations suggest that eDNA is a cue for sensing detrimental environmental conditions in the biofilm. Here, we show that the toxin-antitoxin system (TAS) ParDE4 stimulates cell death in areas of a biofilm with decreased O2 availability. In conditions where O2 availability is low, eDNA concentration is correlated with cell death. Cell dispersal away from biofilms is decreased when parDE4 is deleted, probably due to the lower local eDNA concentration. Expression of parDE4 is positively regulated by O2 and the expression of this operon is decreased in biofilms where O2 availability is low. Thus, a programmed cell death mechanism using an O2-regulated TAS stimulates dispersal away from areas of a biofilm with decreased O2 availability and favors colonization of a new, more hospitable environment.
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Affiliation(s)
- Cecile Berne
- Département de microbiologie, infectiologie et immunologie, Université de MontréalMontréalCanada
| | - Sébastien Zappa
- Département de microbiologie, infectiologie et immunologie, Université de MontréalMontréalCanada
| | - Yves V Brun
- Département de microbiologie, infectiologie et immunologie, Université de MontréalMontréalCanada
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2
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Hou B, Wang CY, Li SW, Zhou LJ, Che YL, Chen QY. Effects of Toxin-Antitoxin System HicAB on Biofilm Formation by Extraintestinal Pathogenic E. coli. Curr Microbiol 2022; 80:50. [PMID: 36542185 DOI: 10.1007/s00284-022-03138-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022]
Abstract
The type II toxin-antitoxin (T-A) HicAB system is abundant in several bacteria and archaea, such as Escherichia coli, Burkholderia Pseudomallei, Yersinia pestis, Pseudomonas aeruginosa, and Streptococcus pneumoniae. This system engages in stress response, virulence, and bacterial persistence. This study showed that the biofilm-forming ability of the hicAB deletion mutant was significantly decreased to moderate ability compared to the extra-intestinal pathogenic Escherichia coli (ExPEC) parent strain and the complemented strain, which are strong biofilm producers. Congo red assay showed that the hicAB mutant maintained the ability to form curli fimbriae. Using RNA-seq and comparative real-time quantitative RT-PCR, we observed the difference in gene expression between the hicAB mutant and the parent strain, which was associated with biofilm formation. Our data indicate that the HicAB type II T-A system has a key role in biofilm formation by ExPEC, which may be associated with outer membrane protein (OMP) gene expression. Collectively, our results indicate that the hicAB type II T-A system is involved in ExPEC biofilm formation.
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Affiliation(s)
- Bo Hou
- Institute of Animal Husbandry and Veterinary Medicine, Fujian Animal Disease Control Technology Development Center, Fujian Academy of Agricultural Sciences, No. 104 Xindian Town, Fuzhou, 350013, Fujian, China.
| | - Chen-Yan Wang
- Institute of Animal Husbandry and Veterinary Medicine, Fujian Animal Disease Control Technology Development Center, Fujian Academy of Agricultural Sciences, No. 104 Xindian Town, Fuzhou, 350013, Fujian, China
| | - Shao-Wen Li
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Lun-Jiang Zhou
- Institute of Animal Husbandry and Veterinary Medicine, Fujian Animal Disease Control Technology Development Center, Fujian Academy of Agricultural Sciences, No. 104 Xindian Town, Fuzhou, 350013, Fujian, China.
| | - Yong-Liang Che
- Institute of Animal Husbandry and Veterinary Medicine, Fujian Animal Disease Control Technology Development Center, Fujian Academy of Agricultural Sciences, No. 104 Xindian Town, Fuzhou, 350013, Fujian, China
| | - Qiu-Yong Chen
- Institute of Animal Husbandry and Veterinary Medicine, Fujian Animal Disease Control Technology Development Center, Fujian Academy of Agricultural Sciences, No. 104 Xindian Town, Fuzhou, 350013, Fujian, China
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The Origin, Function, Distribution, Quantification, and Research Advances of Extracellular DNA. Int J Mol Sci 2022; 23:ijms232213690. [PMID: 36430193 PMCID: PMC9698649 DOI: 10.3390/ijms232213690] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/01/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
In nature, DNA is ubiquitous, existing not only inside but also outside of the cells of organisms. Intracellular DNA (iDNA) plays an essential role in different stages of biological growth, and it is defined as the carrier of genetic information. In addition, extracellular DNA (eDNA) is not enclosed in living cells, accounting for a large proportion of total DNA in the environment. Both the lysis-dependent and lysis-independent pathways are involved in eDNA release, and the released DNA has diverse environmental functions. This review provides an insight into the origin as well as the multiple ecological functions of eDNA. Furthermore, the main research advancements of eDNA in the various ecological environments and the various model microorganisms are summarized. Furthermore, the major methods for eDNA extraction and quantification are evaluated.
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Pan F, Liu M, Altenried S, Lei M, Yang J, Straub H, Schmahl WW, Maniura-Weber K, Guillaume-Gentil O, Ren Q. Uncoupling bacterial attachment on and detachment from polydimethylsiloxane surfaces through empirical and simulation studies. J Colloid Interface Sci 2022; 622:419-430. [PMID: 35525145 DOI: 10.1016/j.jcis.2022.04.084] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/10/2022] [Accepted: 04/13/2022] [Indexed: 10/18/2022]
Abstract
Bacterial infections related to medical devices can cause severe problems, whose solution requires in-depth understanding of the interactions between bacteria and surfaces. This work investigates the influence of surface physicochemistry on bacterial attachment and detachment under flow through both empirical and simulation studies. We employed polydimethylsiloxane (PDMS) substrates having different degrees of crosslinking as the model material and the extended Derjaguin - Landau - Verwey - Overbeek model as the simulation method. Experimentally, the different PDMS materials led to similar numbers of attached bacteria, which can be rationalized by the identical energy barriers simulated between bacteria and the different materials. However, different numbers of residual bacteria after detachment were observed, which was suggested by simulation that the detachment process is determined by the interfacial physicochemistry rather than the mechanical property of a material. This finding is further supported by analyzing the bacteria detachment from PDMS substrates from which non-crosslinked polymer chains had been removed: similar numbers of residual bacteria were found on the extracted PDMS substrates. The knowledge gained in this work can facilitate the projection of bacterial colonization on a given surface.
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Affiliation(s)
- Fei Pan
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Mengdi Liu
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland; Department of Earth- and Environmental Sciences, Ludwig Maximilian University of Munich, Theresienstrasse 41, 80333 Munich, Germany
| | - Stefanie Altenried
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Min Lei
- College of Textiles, Donghua University, North Renmin Road 2999, 201620 Shanghai, China
| | - Jiaxin Yang
- Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, CAS, 130022 Changchun, China
| | - Hervé Straub
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Wolfgang W Schmahl
- Department of Earth- and Environmental Sciences, Ludwig Maximilian University of Munich, Theresienstrasse 41, 80333 Munich, Germany
| | - Katharina Maniura-Weber
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Orane Guillaume-Gentil
- Institute of Microbiology, Department of Biology, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
| | - Qun Ren
- Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland.
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Bhowmik P, Rajagopal S, Hmar RV, Singh P, Saxena P, Amar P, Thomas T, Ravishankar R, Nagaraj S, Katagihallimath N, Sarangapani RK, Ramachandran V, Datta S. Validated In Silico Model for Biofilm Formation in Escherichia coli. ACS Synth Biol 2022; 11:713-731. [PMID: 35025506 DOI: 10.1021/acssynbio.1c00445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using Escherichia coli as the representative biofilm former, we report here the development of an in silico model built by simulating events that transform a free-living bacterial entity into self-encased multicellular biofilms. Published literature on ∼300 genes associated with pathways involved in biofilm formation was curated, static maps were created, and suitably interconnected with their respective metabolites using ordinary differential equations. Precise interplay of genetic networks that regulate the transitory switching of bacterial growth pattern in response to environmental changes and the resultant multicomponent synthesis of the extracellular matrix were appropriately represented. Subsequently, the in silico model was analyzed by simulating time-dependent changes in the concentration of components by using the R and python environment. The model was validated by simulating and verifying the impact of key gene knockouts (KOs) and systematic knockdowns on biofilm formation, thus ensuring the outcomes were comparable with the reported literature. Similarly, specific gene KOs in laboratory and pathogenic E. coli were constructed and assessed. MiaA, YdeO, and YgiV were found to be crucial in biofilm development. Furthermore, qRT-PCR confirmed the elevation of expression in biofilm-forming clinical isolates. Findings reported in this study offer opportunities for identifying biofilm inhibitors with applications in multiple industries. The application of this model can be extended to the health care sector specifically to develop novel adjunct therapies that prevent biofilms in medical implants and reduce emergence of biofilm-associated resistant polymicrobial-chronic infections. The in silico framework reported here is open source and accessible for further enhancements.
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Affiliation(s)
- Purnendu Bhowmik
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
- The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka 560064, India
| | - Sreenath Rajagopal
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Rothangamawi Victoria Hmar
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Purnima Singh
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Pragya Saxena
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Prakruthi Amar
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Teby Thomas
- St. John’s Research Institute, Bengaluru, Karnataka 560034, India
| | - Rajani Ravishankar
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Savitha Nagaraj
- St. John’s Medical College, Bengaluru, Karnataka 560034, India
| | - Nainesh Katagihallimath
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
- The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka 560064, India
| | - Ramanujan Kadambi Sarangapani
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
| | - Vasanthi Ramachandran
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
- The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka 560064, India
| | - Santanu Datta
- Bugworks Research India Pvt. Ltd., Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India
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Zadeh RG, Kalani BS, Ari MM, Talebi M, Razavi S, Jazi FM. Isolation of Persister Cell within the Biofilm and Relative Gene Expression Analysis of Type II Toxin-antitoxin System in Pseudomonas aeruginosa Isolates in the Exponential and Stationary Phases. J Glob Antimicrob Resist 2021; 28:30-37. [PMID: 34922056 DOI: 10.1016/j.jgar.2021.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/22/2021] [Accepted: 11/22/2021] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES Chronic infections and treatment failure are concerning issues in patients with Pseudomonas aeruginosa infections. Persister cell formation in biofilm is considered a key reason for antibiotic resistance and treatment failure. Thus, in this study, the expression of TA type II system genes (relBE, Xre-COG5654, vapBC, and Xre-GNAT) in persister cells of biofilm was evaluated in the presence of ciprofloxacin and colistin antibiotics during exponential and stationary phases. METHODS The impacts of ciprofloxacin and colistin were examined on persister cell formation of biofilm during the exponential and stationary phases of P. aeruginosa strains through colony count method at different time intervals in the presence of 5-fold MIC of ciprofloxacin and colistin. Furthermore, the expression of relBE, Xre-COG5654, vapBC, and Xre-GNAT genes in P. aeruginosa strains underwent antibiotic treatment for 3.5 hours during the exponential and stationary phases via qRT-PCR. RESULTS Formation of persister cells was observed in the biofilms by P. aeruginosa strains in the presence of 5-fold MIC of ciprofloxacin and colistin when compared with the control group after 3.5 hours of incubation during both exponential and stationary phases. The number of persister cells of biofilm was higher in the stationary phase than in the exponential phase. According to the findings of qRT-PCR, ciprofloxacin and colistin may induce persister cells through enhancing the expression of type II TA systems during stationary and exponential phases. CONCLUSION The result of this study indicated that ciprofloxacin and colistin have the potential to increase persister cells formation in biofilm through influencing the expression of type II TA systems.
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Affiliation(s)
- Rezvan Golmoradi Zadeh
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Behrooz Sadeghi Kalani
- Department of Microbiology, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran; Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Marzie Mahdizade Ari
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Malihe Talebi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Shabnam Razavi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Faramarz Masjedian Jazi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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Campoccia D, Montanaro L, Arciola CR. Tracing the origins of extracellular DNA in bacterial biofilms: story of death and predation to community benefit. BIOFOULING 2021; 37:1022-1039. [PMID: 34823431 DOI: 10.1080/08927014.2021.2002987] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
Extracellular DNA (eDNA) is a macromolecule copiously found in various natural microenvironments, but its origin and significance still remain partly mysterious phenomena. Here, the multifaceted origins of eDNA in bacterial biofilms are explored. The release of eDNA can follow a suicidal programmed bacterial apoptosis or a fratricide-induced death, under the control of quorum sensing systems or triggered by specific stressors. eDNA can be released into the extracellular space or as a free macromolecule or enclosed within membrane vesicles or even through an explosion of bubbles. eDNA can also be derived from host tissue cells through bacterial cytolytic/proapoptotic toxins or stolen from neutrophil extracellular traps (NETs). eDNA can alternatively be produced by lysis-independent mechanisms. Sub-inhibitory doses of antibiotics, by killing a fraction of bacteria, result in stimulating the release of eDNA. Even phages appear to play a role in favoring eDNA release. Unveiling the origins of eDNA is critical to correctly address biofilm-associated infections.
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Affiliation(s)
- Davide Campoccia
- Laboratorio di Patologia delle Infezioni Associate all'Impianto, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Lucio Montanaro
- Laboratorio di Patologia delle Infezioni Associate all'Impianto, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Carla Renata Arciola
- Laboratorio di Patologia delle Infezioni Associate all'Impianto, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
- Laboratorio di Immunoreumatologia e Rigenerazione Tissutale, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy
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Kamruzzaman M, Wu AY, Iredell JR. Biological Functions of Type II Toxin-Antitoxin Systems in Bacteria. Microorganisms 2021; 9:microorganisms9061276. [PMID: 34208120 PMCID: PMC8230891 DOI: 10.3390/microorganisms9061276] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 12/14/2022] Open
Abstract
After the first discovery in the 1980s in F-plasmids as a plasmid maintenance system, a myriad of toxin-antitoxin (TA) systems has been identified in bacterial chromosomes and mobile genetic elements (MGEs), including plasmids and bacteriophages. TA systems are small genetic modules that encode a toxin and its antidote and can be divided into seven types based on the nature of the antitoxin molecules and their mechanism of action to neutralise toxins. Among them, type II TA systems are widely distributed in chromosomes and plasmids and the best studied so far. Maintaining genetic material may be the major function of type II TA systems associated with MGEs, but the chromosomal TA systems contribute largely to functions associated with bacterial physiology, including the management of different stresses, virulence and pathogenesis. Due to growing interest in TA research, extensive work has been conducted in recent decades to better understand the physiological roles of these chromosomally encoded modules. However, there are still controversies about some of the functions associated with different TA systems. This review will discuss the most current findings and the bona fide functions of bacterial type II TA systems.
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Affiliation(s)
- Muhammad Kamruzzaman
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia;
- Correspondence: (M.K.); (J.R.I.)
| | - Alma Y. Wu
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia;
| | - Jonathan R. Iredell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia;
- Westmead Hospital, Westmead, NSW 2145, Australia
- Correspondence: (M.K.); (J.R.I.)
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Srivastava A, Pati S, Kaushik H, Singh S, Garg LC. Toxin-antitoxin systems and their medical applications: current status and future perspective. Appl Microbiol Biotechnol 2021; 105:1803-1821. [PMID: 33582835 DOI: 10.1007/s00253-021-11134-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 12/11/2022]
Abstract
Almost all bacteria synthesize two types of toxins-one for its survival by regulating different cellular processes and another as a strategy to interact with host cells for pathogenesis. Usually, "bacterial toxins" are contemplated as virulence factors that harm the host organism. However, toxins produced by bacteria, as a survival strategy against the host, also hamper its cellular processes. To overcome this, the bacteria have evolved with the production of a molecule, referred to as antitoxin, to negate the deleterious effect of the toxin against itself. The toxin and antitoxins are encoded by a two-component toxin-antitoxin (TA) system. The antitoxin, a protein or RNA, sequesters the toxins of the TA system for neutralization within the bacterial cell. In this review, we have described different TA systems of bacteria and their potential medical and biotechnological applications. It is of interest to note that while bacterial toxin-antitoxin systems have been well studied, the TA system in unicellular eukaryotes, though predicted by the investigators, have never been paid the desired attention. In the present review, we have also touched upon the TA system of eukaryotes identified to date. KEY POINTS: Bacterial toxins harm the host and also affect the bacterial cellular processes. The antitoxin produced by bacteria protect it from the toxin's harmful effects. The toxin-antitoxin systems can be targeted for various medical applications.
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Affiliation(s)
- Akriti Srivastava
- Department of Life Sciences, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida, Uttar Pradesh, 201314, India
| | - Soumya Pati
- Department of Life Sciences, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida, Uttar Pradesh, 201314, India
| | - Himani Kaushik
- Gene Regulation Laboratory, National Institute of Immunology, New Delhi, 110067, India
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Lalit C Garg
- Gene Regulation Laboratory, National Institute of Immunology, New Delhi, 110067, India.
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Yang B, Chen C, Sun Y, Cao L, Zhang D, Sun W, Zhang L, Wang G, Shan X, Kang Y, Qian A. Comparative genomic analysis of different virulence strains reveals reasons for the increased virulence of Aeromonas veronii. JOURNAL OF FISH DISEASES 2021; 44:11-24. [PMID: 33137224 DOI: 10.1111/jfd.13262] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 06/11/2023]
Abstract
Aeromonas veronii is an important zoonotic and aquatic agent. More and more cases have shown that it has caused huge economic losses in the aquaculture industry in addition to threatening human health. But the reasons for the increasing virulence of A. veronii are still unclear. In order to further understand the reasons for the increased virulence of A. veronii, we conducted a comparative analysis of the genomes of A. veronii with different virulence. The analysis revealed that there are multiple virulence factors, such as those related to fimbriae, flagella, toxins, iron ion uptake systems and type II, type III and type VI secretion systems in the virulent strain TH0426 genome. And comparative analysis showed that there were two complete type III secretion systems (API1 and API2), of which the API2 and iron ion transport system were unique to the TH0426 strain. In addition, TH0426 strain also has unique functional gene clusters, which may play important roles in terms of resisting infection, adapting to different environments and genetic evolution. These particular virulence factors and gene clusters may be the important reasons for the increased virulence. These insights will provide a reference for the study of the pathogenesis of A. veronii.
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Affiliation(s)
- Bintong Yang
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
- College of Life Science, Changchun Sci-Tech University, Changchun, China
| | - Chong Chen
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
| | - Yufeng Sun
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
| | - Linan Cao
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
| | - Dongxing Zhang
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
| | - Wuwen Sun
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
| | - Lei Zhang
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
| | - Guiqin Wang
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
| | - Xiaofeng Shan
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
| | - Yuanhuan Kang
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
| | - Aidong Qian
- College of Animal Science and Technology, Jilin Provincial Engineering Research Center of Animal Probiotics, Key Lab of Animal Production, Product Quality and Security, Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, China
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Narimisa N, Amraei F, Kalani BS, Azarnezhad A, Jazi FM. Biofilm establishment, biofilm persister cell formation, and relative gene expression analysis of type II toxin-antitoxin system in Klebsiella pneumoniae. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100846] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Balaure PC, Grumezescu AM. Recent Advances in Surface Nanoengineering for Biofilm Prevention and Control. Part I: Molecular Basis of Biofilm Recalcitrance. Passive Anti-Biofouling Nanocoatings. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1230. [PMID: 32599948 PMCID: PMC7353097 DOI: 10.3390/nano10061230] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/19/2020] [Accepted: 06/20/2020] [Indexed: 12/17/2022]
Abstract
Medical device-associated infections are becoming a leading cause of morbidity and mortality worldwide, prompting researchers to find new, more effective ways to control the bacterial colonisation of surfaces and biofilm development. Bacteria in biofilms exhibit a set of "emergent properties", meaning those properties that are not predictable from the study of free-living bacterial cells. The social coordinated behaviour in the biofilm lifestyle involves intricate signaling pathways and molecular mechanisms underlying the gain in resistance and tolerance (recalcitrance) towards antimicrobial agents as compared to free-floating bacteria. Nanotechnology provides powerful tools to disrupt the processes responsible for recalcitrance development in all stages of the biofilm life cycle. The present paper is a state-of-the-art review of the surface nanoengineering strategies currently used to design antibiofilm coatings. The review is structurally organised in two parts according to the targeted biofilm life cycle stages and molecular mechanisms intervening in recalcitrance development. Therefore, in the present first part, we begin with a presentation of the current knowledge of the molecular mechanisms responsible for increased recalcitrance that have to be disrupted. Further, we deal with passive surface nanoengineering strategies that aim to prevent bacterial cells from settling onto a biotic or abiotic surface. Both "fouling-resistant" and "fouling release" strategies are addressed as well as their synergic combination in a single unique nanoplatform.
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Affiliation(s)
- Paul Cătălin Balaure
- “Costin Nenitzescu” Department of Organic Chemistry, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, G. Polizu Street 1-7, 011061 Bucharest, Romania
| | - Alexandru Mihai Grumezescu
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, G. Polizu Street 1-7, 011061 Bucharest, Romania
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Xu J, Xia K, Li P, Qian C, Li Y, Liang X. Functional investigation of the chromosomal ccdAB and hipAB operon in Escherichia coli Nissle 1917. Appl Microbiol Biotechnol 2020; 104:6731-6747. [PMID: 32535695 PMCID: PMC7293176 DOI: 10.1007/s00253-020-10733-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/23/2020] [Accepted: 06/07/2020] [Indexed: 12/31/2022]
Abstract
Toxin-antitoxin systems (TASs) have attracted much attention due to their important physiological functions. These small genetic factors have been widely studied mostly in commensal Escherichia coli strains, whereas the role of TASs in the probiotic E. coli Nissle 1917 (EcN) is still elusive. Here, the physiological role of chromosomally encoded type II TASs in EcN was examined. We showed that gene pair ECOLIN_00240-ECOLIN_00245 and ECOLIN_08365-ECOLIN_08370 were two functional TASs encoding CcdAB and HipAB, respectively. The homologs of CcdAB and HipAB were more conserved in E. coli species belonging to pathogenic groups, suggesting their important roles in EcN. CRISPRi-mediated repression of ccdAB and hipAB significantly reduced the biofilm formation of EcN in the stationary phase. Moreover, ccdAB and hipAB were shown to be responsible for the persister formation in EcN. Biofilm and persister formation of EcN controlled by the ccdAB and hipAB were associated with the expression of genes involved in DNA synthesis, SOS response, and stringent response. Besides, CRISPRi was proposed to be an efficient tool in annotating multiple TASs simultaneously. Collectively, our results advance knowledge and understanding of the role of TASs in EcN, which will enhance the utility of EcN in probiotic therapy. Key points • Two TASs in EcN were identified as hipAB and ccdAB. • Knockdown of HipAB and CcdAB resulted in decreased biofilm formation of EcN. • Transcriptional silencing of hipAB and ccdAB affected the persister formation of EcN. • An attractive link between TASs and stress response was unraveled in EcN. • CRISPRi afforded a fast and in situ annotation of multiple TASs simultaneously.
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Affiliation(s)
- Jun Xu
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Kai Xia
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Pinyi Li
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Chenggong Qian
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Yudong Li
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Xinle Liang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China.
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Valentin JD, Qin XH, Fessele C, Straub H, van der Mei HC, Buhmann MT, Maniura-Weber K, Ren Q. Substrate viscosity plays an important role in bacterial adhesion under fluid flow. J Colloid Interface Sci 2019; 552:247-257. [DOI: 10.1016/j.jcis.2019.05.043] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 01/08/2023]
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15
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Hosseini N, Pourhajibagher M, Chiniforush N, Hosseinkhan N, Rezaie P, Bahador A. Modulation of Toxin-Antitoxin System Rnl AB Type II in Phage-Resistant Gammaproteobacteria Surviving Photodynamic Treatment. J Lasers Med Sci 2018; 10:21-28. [PMID: 31360364 DOI: 10.15171/jlms.2019.03] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Type II toxin-antitoxin (TA) systems are the particular type of TA modules which take part in different kinds of cellular actions, such as biofilm formation, persistence, stress endurance, defense of the bacterial cell against multiple phage attacks, plasmid maintenance, and programmed cell death in favor of bacterial population. Although several bioinformatics and Pet lab studies have already been conducted to understand the functionality of already discovered TA systems, still, more work in this area is required. Rnl AB type II TA module, which is composed of RnlA toxin and RnlB antitoxin, is a newly discovered type II TA module which takes part in the defense mechanism against T4 bacteriophage attack in Escherichia coli K-12 strain MH1 that has not been widely studied in other bacteria. Because of the significant role of class Gammaproteobacteriacea in a diverse range of health problems, we chose here to focus on this class to survey the presence of the Rnl AB TA module. For better categorization and description of the distribution of this module in this class of bacteria, the corresponding phylogenetic trees are illustrated here. Neighbor-joining and the maximum parsimony methods were used in this study to take a look at the distribution of domains present in RnlA and RnlB proteins, among members of Gammaproteobacteria. Also, the possible roles of photodynamic therapy (PDT) in providing a substrate for better phage therapy are herein discussed.
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Affiliation(s)
- Nava Hosseini
- Department of Microbiology, Faculty of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Maryam Pourhajibagher
- Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Nasim Chiniforush
- Laser Research Center of Dentistry (LRCD), Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Nazanin Hosseinkhan
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Parizad Rezaie
- Department of Microbiology, Faculty of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Abbas Bahador
- Dental Implant Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
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16
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Curli-Containing Enteric Biofilms Inside and Out: Matrix Composition, Immune Recognition, and Disease Implications. Microbiol Mol Biol Rev 2018; 82:82/4/e00028-18. [PMID: 30305312 DOI: 10.1128/mmbr.00028-18] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Biofilms of enteric bacteria are highly complex, with multiple components that interact to fortify the biofilm matrix. Within biofilms of enteric bacteria such as Escherichia coli and Salmonella species, the main component of the biofilm is amyloid curli. Other constituents include cellulose, extracellular DNA, O antigen, and various surface proteins, including BapA. Only recently, the roles of these components in the formation of the enteric biofilm individually and in consortium have been evaluated. In addition to enhancing the stability and strength of the matrix, the components of the enteric biofilm influence bacterial virulence and transmission. Most notably, certain components of the matrix are recognized as pathogen-associated molecular patterns. Systemic recognition of enteric biofilms leads to the activation of several proinflammatory innate immune receptors, including the Toll-like receptor 2 (TLR2)/TLR1/CD14 heterocomplex, TLR9, and NLRP3. In the model of Salmonella enterica serovar Typhimurium, the immune response to curli is site specific. Although a proinflammatory response is generated upon systemic presentation of curli, oral administration of curli ameliorates the damaged intestinal epithelial barrier and reduces the severity of colitis. Furthermore, curli (and extracellular DNA) of enteric biofilms potentiate the autoimmune disease systemic lupus erythematosus (SLE) and promote the fibrillization of the pathogenic amyloid α-synuclein, which is implicated in Parkinson's disease. Homologues of curli-encoding genes are found in four additional bacterial phyla, suggesting that the biomedical implications involved with enteric biofilms are applicable to numerous bacterial species.
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Nahar S, Mizan MFR, Ha AJW, Ha SD. Advances and Future Prospects of Enzyme-Based Biofilm Prevention Approaches in the Food Industry. Compr Rev Food Sci Food Saf 2018; 17:1484-1502. [DOI: 10.1111/1541-4337.12382] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/22/2018] [Accepted: 06/27/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Shamsun Nahar
- Dept. of Food Science and Technology; Chung-Ang Univ.; Anseong Gyeonggi-Do 456-756 Republic of Korea
| | | | - Angela Jie-won Ha
- Dept. of Food Science and Technology; Chung-Ang Univ.; Anseong Gyeonggi-Do 456-756 Republic of Korea
| | - Sang-Do Ha
- Dept. of Food Science and Technology; Chung-Ang Univ.; Anseong Gyeonggi-Do 456-756 Republic of Korea
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18
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Nagler M, Insam H, Pietramellara G, Ascher-Jenull J. Extracellular DNA in natural environments: features, relevance and applications. Appl Microbiol Biotechnol 2018; 102:6343-6356. [PMID: 29858957 PMCID: PMC6061472 DOI: 10.1007/s00253-018-9120-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/15/2018] [Accepted: 05/19/2018] [Indexed: 01/13/2023]
Abstract
Extracellular DNA (exDNA) is abundant in many habitats, including soil, sediments, oceans and freshwater as well as the intercellular milieu of metazoa. For a long time, its origin has been assumed to be mainly lysed cells. Nowadays, research is collecting evidence that exDNA is often secreted actively and is used to perform a number of tasks, thereby offering an attractive target or tool for biotechnological, medical, environmental and general microbiological applications. The present review gives an overview on the main research areas dealing with exDNA, depicts its inherent origins and functions and deduces the potential of existing and emerging exDNA-based applications. Furthermore, it provides an overview on existing extraction methods and indicates common pitfalls that should be avoided whilst working with exDNA.
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Affiliation(s)
- Magdalena Nagler
- Universität Innsbruck, Institute of Microbiology, Technikerstr. 25d, 6020, Innsbruck, Austria.
| | - Heribert Insam
- Universität Innsbruck, Institute of Microbiology, Technikerstr. 25d, 6020, Innsbruck, Austria
| | - Giacomo Pietramellara
- Dipartimento di Scienze delle Produzioni Agroalimentari e dell'Ambiente, Università degli Studi di Firenze, Piazzale delle Cascine 18, 50144, Florence, Italy
| | - Judith Ascher-Jenull
- Universität Innsbruck, Institute of Microbiology, Technikerstr. 25d, 6020, Innsbruck, Austria
- Dipartimento di Scienze delle Produzioni Agroalimentari e dell'Ambiente, Università degli Studi di Firenze, Piazzale delle Cascine 18, 50144, Florence, Italy
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19
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Horng YT, Wang CJ, Chung WT, Chao HJ, Chen YY, Soo PC. Phosphoenolpyruvate phosphotransferase system components positively regulate Klebsiella biofilm formation. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2018; 51:174-183. [DOI: 10.1016/j.jmii.2017.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/07/2017] [Accepted: 01/24/2017] [Indexed: 02/02/2023]
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20
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Shidore T, Triplett LR. Toxin-Antitoxin Systems: Implications for Plant Disease. ANNUAL REVIEW OF PHYTOPATHOLOGY 2017; 55:161-179. [PMID: 28525308 DOI: 10.1146/annurev-phyto-080516-035559] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Toxin-antitoxin (TA) systems are gene modules that are ubiquitous in free-living prokaryotes. Diverse in structure, cellular function, and fitness roles, TA systems are defined by the presence of a toxin gene that suppresses bacterial growth and a toxin-neutralizing antitoxin gene, usually encoded in a single operon. Originally viewed as DNA maintenance modules, TA systems are now thought to function in many roles, including bacterial stress tolerance, virulence, phage defense, and biofilm formation. However, very few studies have investigated the significance of TA systems in the context of plant-microbe interactions. This review discusses the potential impact and application of TA systems in plant-associated bacteria, guided by insights gained from animal-pathogenic model systems.
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Affiliation(s)
- T Shidore
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511:
| | - L R Triplett
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511:
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21
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Sadiq FA, Flint S, Li Y, Liu T, Lei Y, Sakandar HA, He G. New mechanistic insights into the motile-to-sessile switch in various bacteria with particular emphasis on Bacillus subtilis and Pseudomonas aeruginosa: a review. BIOFOULING 2017; 33:306-326. [PMID: 28347177 DOI: 10.1080/08927014.2017.1304541] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/04/2017] [Indexed: 06/06/2023]
Abstract
A biofilm is a complex assemblage of microbial communities adhered to a biotic or an abiotic surface which is embedded within a self-produced matrix of extracellular polymeric substances. Many transcriptional regulators play a role in triggering a motile-sessile switch and in consequently producing the biofilm matrix. This review is aimed at highlighting the role of two nucleotide signaling molecules (c-di-GMP and c-di-AMP), toxin antitoxin modules and a novel transcriptional regulator BolA in biofilm formation in various bacteria. In addition, it highlights the common themes that have appeared in recent research regarding the key regulatory components and signal transduction pathways that help Bacillus subtilis and Pseudomonas aeruginosa to acquire the biofilm mode of life.
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Affiliation(s)
- Faizan A Sadiq
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | - Steve Flint
- b School of Food and Nutrition , Massey University , Palmerston North , New Zealand
| | - Yun Li
- c School of Life Sciences and Food Technology , Hanshan Normal University , Chaozhou , PR China
| | - TongJie Liu
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | - Yuan Lei
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | | | - GuoQing He
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
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22
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Structure, Biology, and Therapeutic Application of Toxin-Antitoxin Systems in Pathogenic Bacteria. Toxins (Basel) 2016; 8:toxins8100305. [PMID: 27782085 PMCID: PMC5086665 DOI: 10.3390/toxins8100305] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 01/09/2023] Open
Abstract
Bacterial toxin–antitoxin (TA) systems have received increasing attention for their diverse identities, structures, and functional implications in cell cycle arrest and survival against environmental stresses such as nutrient deficiency, antibiotic treatments, and immune system attacks. In this review, we describe the biological functions and the auto-regulatory mechanisms of six different types of TA systems, among which the type II TA system has been most extensively studied. The functions of type II toxins include mRNA/tRNA cleavage, gyrase/ribosome poison, and protein phosphorylation, which can be neutralized by their cognate antitoxins. We mainly explore the similar but divergent structures of type II TA proteins from 12 important pathogenic bacteria, including various aspects of protein–protein interactions. Accumulating knowledge about the structure–function correlation of TA systems from pathogenic bacteria has facilitated a novel strategy to develop antibiotic drugs that target specific pathogens. These molecules could increase the intrinsic activity of the toxin by artificially interfering with the intermolecular network of the TA systems.
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23
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Bloom-Ackermann Z, Steinberg N, Rosenberg G, Oppenheimer-Shaanan Y, Pollack D, Ely S, Storzi N, Levy A, Kolodkin-Gal I. Toxin-Antitoxin systems eliminate defective cells and preserve symmetry in Bacillus subtilis biofilms. Environ Microbiol 2016; 18:5032-5047. [PMID: 27450630 DOI: 10.1111/1462-2920.13471] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/07/2016] [Accepted: 07/20/2016] [Indexed: 01/02/2023]
Abstract
Toxin-antitoxin modules are gene pairs encoding a toxin and its antitoxin, and are found on the chromosomes of many bacteria, including pathogens. Here, we characterize the specific contribution of the TxpA and YqcG toxins in elimination of defective cells from developing Bacillus subtilis biofilms. On nutrient limitation, defective cells accumulated in the biofilm breaking its symmetry. Deletion of the toxins resulted in accumulation of morphologically abnormal cells, and interfered with the proper development of the multicellular community. Dual physiological responses are of significance for TxpA and YqcG activation: nitrogen deprivation enhances the transcription of both TxpA and YqcG toxins, and simultaneously sensitizes the biofilm cells to their activity. Furthermore, we demonstrate that while both toxins when overexpressed affect the morphology of the developing biofilm, the toxin TxpA can act to lyse and dissolve pre-established B. subtilis biofilms.
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Affiliation(s)
- Zohar Bloom-Ackermann
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Nitai Steinberg
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Gili Rosenberg
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | | | - Dan Pollack
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Shir Ely
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Nimrod Storzi
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Asaf Levy
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Ilana Kolodkin-Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
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24
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Yakimov MM, Crisafi F, Messina E, Smedile F, Lopatina A, Denaro R, Pieper DH, Golyshin PN, Giuliano L. Analysis of defence systems and a conjugative IncP-1 plasmid in the marine polyaromatic hydrocarbons-degrading bacterium Cycloclasticus sp. 78-ME. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:508-519. [PMID: 27345842 DOI: 10.1111/1758-2229.12424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/24/2016] [Indexed: 06/06/2023]
Abstract
Marine prokaryotes have evolved a broad repertoire of defence systems to protect their genomes from lateral gene transfer including innate or acquired immune systems and infection-induced programmed cell suicide and dormancy. Here we report on the analysis of multiple defence systems present in the genome of the strain Cycloclasticus sp. 78-ME isolated from petroleum deposits of the tanker 'Amoco Milford Haven'. Cycloclasticus are ubiquitous bacteria globally important in polyaromatic hydrocarbons degradation in marine environments. Two 'defence islands' were identified in 78-ME genome: the first harbouring CRISPR-Cas with toxin-antitoxin system, while the second was composed by an array of genes for toxin-antitoxin and restriction-modification proteins. Among all identified spacers of CRISPR-Cas system only seven spacers match sequences of phages and plasmids. Furthermore, a conjugative plasmid p7ME01, which belongs to a new IncP-1θ ancestral archetype without any accessory mobile elements was found in 78-ME. Our results provide the context to the co-occurrence of diverse defence mechanisms in the genome of Cycloclasticus sp. 78-ME, which protect the genome of this highly specialized PAH-degrader. This study contributes to the further understanding of complex networks established in petroleum-based microbial communities.
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Affiliation(s)
- Michail M Yakimov
- Institute for Coastal Marine Environment, CNR, Spianata S. Raineri 86, Messina, 98122, Italy
| | - Francesca Crisafi
- Institute for Coastal Marine Environment, CNR, Spianata S. Raineri 86, Messina, 98122, Italy
| | - Enzo Messina
- Institute for Coastal Marine Environment, CNR, Spianata S. Raineri 86, Messina, 98122, Italy
| | - Francesco Smedile
- Institute for Coastal Marine Environment, CNR, Spianata S. Raineri 86, Messina, 98122, Italy
| | - Anna Lopatina
- Institute of Molecular Genetics and Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Renata Denaro
- Institute for Coastal Marine Environment, CNR, Spianata S. Raineri 86, Messina, 98122, Italy
| | - Dietmar H Pieper
- Microbial Interactions and Processes Research Group, HZI - Helmholtz Centre for Infection Research, Inhoffenstraße 7, Braunschweig, D-38124, Germany
| | - Peter N Golyshin
- School of Biological Sciences, Bangor University, ECW Bldg Deiniol Rd, Bangor, Gwynedd, LL57 2UW, United Kingdom
| | - Laura Giuliano
- Institute for Coastal Marine Environment, CNR, Spianata S. Raineri 86, Messina, 98122, Italy
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25
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Emerging Roles of Toxin-Antitoxin Modules in Bacterial Pathogenesis. Molecules 2016; 21:molecules21060790. [PMID: 27322231 PMCID: PMC6273597 DOI: 10.3390/molecules21060790] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/06/2016] [Accepted: 06/13/2016] [Indexed: 11/17/2022] Open
Abstract
Toxin-antitoxin (TA) cassettes are encoded widely by bacteria. The modules typically comprise a protein toxin and protein or RNA antitoxin that sequesters the toxin factor. Toxin activation in response to environmental cues or other stresses promotes a dampening of metabolism, most notably protein translation, which permits survival until conditions improve. Emerging evidence also implicates TAs in bacterial pathogenicity. Bacterial persistence involves entry into a transient semi-dormant state in which cells survive unfavorable conditions including killing by antibiotics, which is a significant clinical problem. TA complexes play a fundamental role in inducing persistence by downregulating cellular metabolism. Bacterial biofilms are important in numerous chronic inflammatory and infectious diseases and cause serious therapeutic problems due to their multidrug tolerance and resistance to host immune system actions. Multiple TAs influence biofilm formation through a network of interactions with other factors that mediate biofilm production and maintenance. Moreover, in view of their emerging contributions to bacterial virulence, TAs are potential targets for novel prophylactic and therapeutic approaches that are required urgently in an era of expanding antibiotic resistance. This review summarizes the emerging evidence that implicates TAs in the virulence profiles of a diverse range of key bacterial pathogens that trigger serious human disease.
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26
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Desperate times call for desperate measures: benefits and costs of toxin-antitoxin systems. Curr Genet 2016; 63:69-74. [PMID: 27276988 DOI: 10.1007/s00294-016-0622-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 06/03/2016] [Accepted: 06/04/2016] [Indexed: 10/21/2022]
Abstract
Toxin-antitoxin (TA) loci were first described as killing systems for plasmid maintenance. The surprisingly abundant presence of TA loci in bacterial chromosomes has stimulated an extensive research in the recent decade aimed to understand the biological importance of these potentially deadly systems. Accumulating evidence suggests that the evolutionary success of genomic TA systems could be explained by their ability to increase bacterial fitness under stress conditions. While TA systems remain quiescent under favorable growth conditions, the toxins can be activated in response to stress resulting in growth suppression and development of stress-tolerant dormant state. Yet, several studies suggest that the TA-mediated stress protection is costly and traded off against decreased fitness under normal growth conditions. Here, we give an overview of the fitness benefits of the chromosomal TA systems, and discuss the costs of TA-mediated stress protection.
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27
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Brown HL, Hanman K, Reuter M, Betts RP, van Vliet AHM. Campylobacter jejuni biofilms contain extracellular DNA and are sensitive to DNase I treatment. Front Microbiol 2015. [PMID: 26217328 PMCID: PMC4498105 DOI: 10.3389/fmicb.2015.00699] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Biofilms make an important contribution to survival and transmission of bacterial pathogens in the food chain. The human pathogen Campylobacter jejuni is known to form biofilms in vitro in food chain-relevant conditions, but the exact roles and composition of the extracellular matrix are still not clear. Extracellular DNA has been found in many bacterial biofilms and can be a major component of the extracellular matrix. Here we show that extracellular DNA is also an important component of the C. jejuni biofilm when attached to stainless steel surfaces, in aerobic conditions and on conditioned surfaces. Degradation of extracellular DNA by exogenous addition of DNase I led to rapid biofilm removal, without loss of C. jejuni viability. Following treatment of a surface with DNase I, C. jejuni was unable to re-establish a biofilm population within 48 h. Similar results were obtained by digesting extracellular DNA with restriction enzymes, suggesting the need for high molecular weight DNA. Addition of C. jejuni genomic DNA containing an antibiotic resistance marker resulted in transfer of the antibiotic resistance marker to susceptible cells in the biofilm, presumably by natural transformation. Taken together, this suggest that eDNA is not only an important component of C. jejuni biofilms and subsequent food chain survival of C. jejuni, but may also contribute to the spread of antimicrobial resistance in C. jejuni. The degradation of extracellular DNA with enzymes such as DNase I is a rapid method to remove C. jejuni biofilms, and is likely to potentiate the activity of antimicrobial treatments and thus synergistically aid disinfection treatments.
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Affiliation(s)
- Helen L Brown
- Gut Health and Food Safety Programme, Institute of Food Research Norwich, UK ; Cardiff School of Health Sciences, Cardiff Metropolitan University Cardiff, UK
| | - Kate Hanman
- Gut Health and Food Safety Programme, Institute of Food Research Norwich, UK
| | - Mark Reuter
- Gut Health and Food Safety Programme, Institute of Food Research Norwich, UK
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Suhaimi NSM, Yap KP, Ajam N, Thong KL. Genome sequence of Kosakonia radicincitans UMEnt01/12, a bacterium associated with bacterial wilt diseased banana plant. FEMS Microbiol Lett 2015; 358:11-3. [PMID: 25047976 DOI: 10.1111/1574-6968.12537] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/07/2014] [Accepted: 07/12/2014] [Indexed: 11/29/2022] Open
Abstract
Kosakonia radicincitans (formerly known as Enterobacter radicincitans), an endophytic bacterium was isolated from the symptomatic tissues of bacterial wilt diseased banana (Musa spp.) plant in Malaysia. The total genome size of K. radicincitans UMEnt01/12 is 5 783 769 bp with 5463 coding sequences (CDS), 75 tRNAs, and 9 rRNAs. The annotated draft genome of the K. radicincitans UMEnt01/12 strain might shed light on its role as a bacterial wilt-associated bacterium.
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Brown HL, Reuter M, Hanman K, Betts RP, van Vliet AHM. Prevention of biofilm formation and removal of existing biofilms by extracellular DNases of Campylobacter jejuni. PLoS One 2015; 10:e0121680. [PMID: 25803828 PMCID: PMC4372405 DOI: 10.1371/journal.pone.0121680] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 02/02/2015] [Indexed: 12/31/2022] Open
Abstract
The fastidious nature of the foodborne bacterial pathogen Campylobacter jejuni contrasts with its ability to survive in the food chain. The formation of biofilms, or the integration into existing biofilms by C. jejuni, is thought to contribute to food chain survival. As extracellular DNA (eDNA) has previously been proposed to play a role in C. jejuni biofilms, we have investigated the role of extracellular DNases (eDNases) produced by C. jejuni in biofilm formation. A search of 2791 C. jejuni genomes highlighted that almost half of C. jejuni genomes contains at least one eDNase gene, but only a minority of isolates contains two or three of these eDNase genes, such as C. jejuni strain RM1221 which contains the cje0256, cje0566 and cje1441 eDNase genes. Strain RM1221 did not form biofilms, whereas the eDNase-negative strains NCTC 11168 and 81116 did. Incubation of pre-formed biofilms of NCTC 11168 with live C. jejuni RM1221 or with spent medium from a RM1221 culture resulted in removal of the biofilm. Inactivation of the cje1441 eDNase gene in strain RM1221 restored biofilm formation, and made the mutant unable to degrade biofilms of strain NCTC 11168. Finally, C. jejuni strain RM1221 was able to degrade genomic DNA from C. jejuni NCTC 11168, 81116 and RM1221, whereas strain NCTC 11168 and the RM1221 cje1441 mutant were unable to do so. This was mirrored by an absence of eDNA in overnight cultures of C. jejuni RM1221. This suggests that the activity of eDNases in C. jejuni affects biofilm formation and is not conducive to a biofilm lifestyle. These eDNases do however have a potential role in controlling biofilm formation by C. jejuni strains in food chain relevant environments.
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Affiliation(s)
- Helen L. Brown
- Institute of Food Research, Norwich Research Park, Colney Lane, Norwich, NR4 7UA, United Kingdom
| | - Mark Reuter
- Institute of Food Research, Norwich Research Park, Colney Lane, Norwich, NR4 7UA, United Kingdom
| | - Kate Hanman
- Institute of Food Research, Norwich Research Park, Colney Lane, Norwich, NR4 7UA, United Kingdom
| | - Roy P. Betts
- Campden BRI, Station Road, Chipping Campden, Gloucestershire, GL55 6LD, United Kingdom
| | - Arnoud H. M. van Vliet
- Institute of Food Research, Norwich Research Park, Colney Lane, Norwich, NR4 7UA, United Kingdom
- * E-mail:
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30
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Fiedoruk K, Daniluk T, Swiecicka I, Sciepuk M, Leszczynska K. Type II toxin-antitoxin systems are unevenly distributed among Escherichia coli phylogroups. MICROBIOLOGY-SGM 2014; 161:158-167. [PMID: 25378561 DOI: 10.1099/mic.0.082883-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Type II toxin-antitoxin systems (TAs) are bicistronic operons ubiquitous in prokaryotic genomes, displaying multilevel association with cell physiology. Various possible functions have been assigned to TAs, ranging from beneficial for their hosts, such as a stress response, dormancy and protection against genomic parasites, to detrimental or useless functions, such as selfish alleles. As there is a link between several Escherichia coli features (e.g. virulence, lifestyle) and the phylogeny of this species, we hypothesized a similar association with TAs. Using PCR we studied the distribution of 15 chromosomal and plasmidic type II TA loci in 84 clinical E. coli isolates in relation to their main phylogenetic groups (A, B1, B2 and D). In addition, we performed in silico searching of these TA loci in 60 completely sequenced E. coli genomes deposited in GenBank. The highest number of TA loci per strain was observed in group A (mean 8.2, range 5-12) and the lowest in group B2 (mean 4.2, range 2-8). Moreover, significant differences in the prevalence of nine chromosomal TAs among E. coli phylogroups were noted. In conclusion, the presence of some chromosomal TAs in E. coli is phylogroup-related rather than a universal feature of the species. In addition, their limited collection in group B2 clearly distinguish it from the other E. coli phylogroups.
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Affiliation(s)
- Krzysztof Fiedoruk
- Department of Microbiology, Medical University of Bialystok, 2C Mickiewicza Street, 15-222 Bialystok, Poland
| | - Tamara Daniluk
- Department of Microbiology, Medical University of Bialystok, 2C Mickiewicza Street, 15-222 Bialystok, Poland
| | - Izabela Swiecicka
- Department of Microbiology, University of Bialystok, 20B Swierkowa Street, 15-950 Bialystok, Poland
| | - Malgorzata Sciepuk
- Department of Microbiology, Medical University of Bialystok, 2C Mickiewicza Street, 15-222 Bialystok, Poland
| | - Katarzyna Leszczynska
- Department of Microbiology, Medical University of Bialystok, 2C Mickiewicza Street, 15-222 Bialystok, Poland
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31
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Iron triggers λSo prophage induction and release of extracellular DNA in Shewanella oneidensis MR-1 biofilms. Appl Environ Microbiol 2014; 80:5304-16. [PMID: 24951794 DOI: 10.1128/aem.01480-14] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prophages are ubiquitous elements within bacterial chromosomes and affect host physiology and ecology in multiple ways. We have previously demonstrated that phage-induced lysis is required for extracellular DNA (eDNA) release and normal biofilm formation in Shewanella oneidensis MR-1. Here, we investigated the regulatory mechanisms of prophage λSo spatiotemporal induction in biofilms. To this end, we used a functional fluorescence fusion to monitor λSo activation in various mutant backgrounds and in response to different physiological conditions. λSo induction occurred mainly in a subpopulation of filamentous cells in a strictly RecA-dependent manner, implicating oxidative stress-induced DNA damage as the major trigger. Accordingly, mutants affected in the oxidative stress response (ΔoxyR) or iron homeostasis (Δfur) displayed drastically increased levels of phage induction and abnormal biofilm formation, while planktonic cells were not or only marginally affected. To further investigate the role of oxidative stress, we performed a mutant screen and identified two independent amino acid substitutions in OxyR (T104N and L197P) that suppress induction of λSo by hydrogen peroxide (H2O2). However, λSo induction was not suppressed in biofilms formed by both mutants, suggesting a minor role of intracellular H2O2 in this process. In contrast, addition of iron to biofilms strongly enhanced λSo induction and eDNA release, while both processes were significantly suppressed at low iron levels, strongly indicating that iron is the limiting factor. We conclude that uptake of iron during biofilm formation triggers λSo-mediated lysis of a subpopulation of cells, likely by an increase in iron-mediated DNA damage sensed by RecA.
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32
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Abstract
TA (toxin-antitoxin) systems are widely distributed amongst bacteria and are associated with the formation of antibiotic tolerant (persister) cells that may have involvement in chronic and recurrent disease. We show that overexpression of the Burkholderia pseudomallei HicA toxin causes growth arrest and increases the number of persister cells tolerant to ciprofloxacin or ceftazidime. Furthermore, our data show that persistence towards ciprofloxacin or ceftazidime can be differentially modulated depending on the level of induction of HicA expression. Deleting the hicAB locus from B. pseudomallei K96243 significantly reduced persister cell frequencies following exposure to ciprofloxacin, but not ceftazidime. The structure of HicA(H24A) was solved by NMR and forms a dsRBD-like (dsRNA-binding domain-like) fold, composed of a triple-stranded β-sheet, with two helices packed against one face. The surface of the protein is highly positively charged indicative of an RNA-binding protein and His24 and Gly22 were functionality important residues. This is the first study demonstrating a role for the HicAB system in bacterial persistence and the first structure of a HicA protein that has been experimentally characterized.
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Wen Y, Behiels E, Devreese B. Toxin-Antitoxin systems: their role in persistence, biofilm formation, and pathogenicity. Pathog Dis 2014; 70:240-9. [DOI: 10.1111/2049-632x.12145] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/15/2014] [Accepted: 01/15/2014] [Indexed: 11/29/2022] Open
Affiliation(s)
- Yurong Wen
- Unit for Biological Mass Spectrometry and Proteomics; Laboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE); Ghent University; Ghent Belgium
| | - Ester Behiels
- Unit for Biological Mass Spectrometry and Proteomics; Laboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE); Ghent University; Ghent Belgium
| | - Bart Devreese
- Unit for Biological Mass Spectrometry and Proteomics; Laboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE); Ghent University; Ghent Belgium
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Okshevsky M, Meyer RL. The role of extracellular DNA in the establishment, maintenance and perpetuation of bacterial biofilms. Crit Rev Microbiol 2013; 41:341-52. [PMID: 24303798 DOI: 10.3109/1040841x.2013.841639] [Citation(s) in RCA: 297] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The significance of extracellular DNA (eDNA) in biofilms was overlooked until researchers added DNAse to a Pseudomonas aeruginosa biofilm and watched the biofilm disappear. Now, a decade later, the widespread importance of eDNA in biofilm formation is undisputed, but detailed knowledge about how it promotes biofilm formation and conveys antimicrobial resistance is only just starting to emerge. In this review, we discuss how eDNA is produced, how it aids bacterial adhesion, secures the structural stability of biofilms and contributes to antimicrobial resistance. The appearance of eDNA in biofilms is no accident: It is produced by active secretion or controlled cell lysis - sometimes linked to competence development. eDNA adsorbs to and extends from the cell surface, promoting adhesion to abiotic surfaces through acid-base interactions. In the biofilm, is it less clear how eDNA interacts with cells and matrix components. A few eDNA-binding biomolecules have been identified, revealing new concepts in biofilm formation. Being anionic, eDNA chelates cations and restricts diffusion of cationic antimicrobials. Furthermore, chelation of Mg(2+) triggers a genetic response that further increases resistance. The multifaceted role of eDNA makes it an attractive target to sensitize biofilms to conventional antimicrobial treatment or development of new strategies to combat biofilms.
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Affiliation(s)
- Mira Okshevsky
- Interdisciplinary Nanosicence Center, Aarhus University , Aarhus , Denmark
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Wang H, Huang Y, Wu S, Li Y, Ye Y, Zheng Y, Huang R. Extracellular DNA inhibits Salmonella enterica Serovar Typhimurium and S. enterica Serovar Typhi biofilm development on abiotic surfaces. Curr Microbiol 2013; 68:262-8. [PMID: 24126602 DOI: 10.1007/s00284-013-0468-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 08/23/2013] [Indexed: 11/27/2022]
Abstract
Extracellular DNA (eDNA) was identified and characterized in a 2-day-old biofilms developed by Salmonella enterica ser. Typhimurium SR-11 and S. enterica ser. Typhi ST6 using confocal laser scanning microscopy (CLSM) and enzymatic extraction methods. Results of microtitre plate assay and CLSM analysis showed both Salmonella strains formed significantly more biofilms in the presence of DNase I; Furthermore, a remarkable decrease of biofilm formation was observed when eDNA was added in the inoculation. However, for the pre-established biofilms on polystyrene and glass, no significant difference was observed between the DNase I treated biofilm and the corresponding non-treated controls. In conclusion, these results demonstrate that eDNA is a novel matrix component of Salmonella biofilms. This is the first evidence for the presence of eDNA and its inhibitive and destabilizing effect during biofilm development of S. enterica ser. Typhimurium and S. enterica ser. Typhi on abiotic surfaces.
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Affiliation(s)
- Hu Wang
- Medical College of Soochow University, No. 199, Ren Ai Road, Suzhou, 215123, Jiangsu, People's Republic of China,
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