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Woitschach F, Kloss M, Kischkel S, Macháček T, Reinholdt C, Senz V, Schlodder K, Löbermann M, Grabow N, Reisinger EC, Sombetzki M. Utilization of a highly adaptable murine air pouch model for minimally invasive testing of the inflammatory potential of biomaterials. Front Bioeng Biotechnol 2024; 12:1367366. [PMID: 38737540 PMCID: PMC11082294 DOI: 10.3389/fbioe.2024.1367366] [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: 01/08/2024] [Accepted: 04/08/2024] [Indexed: 05/14/2024] Open
Abstract
Introduction: The biocompatibility of an implanted material strongly determines the subsequent host immune response. After insertion into the body, each medical device causes tissue reactions. How intense and long-lasting these are is defined by the material properties. The so-called foreign body reaction is a reaction leading to the inflammation and wound healing process after implantation. The constantly expanding field of implant technology and the growing areas of application make optimization and adaptation of the materials used inevitable. Methods: In this study, modified liquid silicone rubber (LSR) and two of the most commonly used thermoplastic polyurethanes (TPU) were compared in terms of induced inflammatory response in the body. We evaluated the production of inflammatory cytokines, infiltration of inflammatory cells and encapsulation of foreign bodies in a subcutaneous air-pouch model in mice. In this model, the material is applied in a minimally invasive procedure via a cannula and in one piece, which allows material testing without destroying or crushing the material and thus studying an intact implant surface. The study design includes short-term (6 h) and long-term (10 days) analysis of the host response to the implanted materials. Air-pouch-infiltrating cells were determined by flow cytometry after 6 h and 10 days. Inflammation, fibrosis and angiogenesis markers were analyzed in the capsular tissue by qPCR after 10 days. Results: The foreign body reaction was investigated by macroscopic evaluation and scanning electron microscopy (SEM). Increased leukocyte infiltration was observed in the air-pouch after 6 h, but it markedly diminished after 10 days. After 10 days, capsule formations were observed around the materials without visible inflammatory cells. Discussion: For biocompatibility testing materials are often implanted in muscle tissue. These test methods are not sufficiently conclusive, especially for materials that are intended to come into contact with blood. Our study primarily shows that the presented model is a highly adaptable and minimally invasive test system to test the inflammatory potential of and foreign body reaction to candidate materials and offers more precise analysis options by means of flow cytometry.
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Affiliation(s)
- Franziska Woitschach
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
| | - Marlen Kloss
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
| | - Sabine Kischkel
- Institute for Biomedical Engineering, University Medical Center Rostock, Rostock-Warnemünde, Germany
| | - Tomáš Macháček
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czechia
| | - Cindy Reinholdt
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
| | - Volkmar Senz
- Institute for Biomedical Engineering, University Medical Center Rostock, Rostock-Warnemünde, Germany
| | | | - Micha Löbermann
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
| | - Niels Grabow
- Institute for Biomedical Engineering, University Medical Center Rostock, Rostock-Warnemünde, Germany
| | - Emil C. Reisinger
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
| | - Martina Sombetzki
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
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2
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Li S. Modulation of immunity by tryptophan microbial metabolites. Front Nutr 2023; 10:1209613. [PMID: 37521424 PMCID: PMC10382180 DOI: 10.3389/fnut.2023.1209613] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 05/30/2023] [Indexed: 08/01/2023] Open
Abstract
Tryptophan (Trp) is an essential amino acid that can be metabolized via endogenous and exogenous pathways, including the Kynurenine Pathway, the 5-Hydroxyindole Pathway (also the Serotonin pathway), and the Microbial pathway. Of these, the Microbial Trp metabolic pathways in the gut have recently been extensively studied for their production of bioactive molecules. The gut microbiota plays an important role in host metabolism and immunity, and microbial Trp metabolites can influence the development and progression of various diseases, including inflammatory, cardiovascular diseases, neurological diseases, metabolic diseases, and cancer, by mediating the body's immunity. This review briefly outlines the crosstalk between gut microorganisms and Trp metabolism in the body, starting from the three metabolic pathways of Trp. The mechanisms by which microbial Trp metabolites act on organism immunity are summarized, and the potential implications for disease prevention and treatment are highlighted.
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Wang Y, Jiménez DJ, Zhang Z, van Elsas JD. Functioning of a tripartite lignocellulolytic microbial consortium cultivated under two shaking conditions: a metatranscriptomic study. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:54. [PMID: 36991472 DOI: 10.1186/s13068-023-02289-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 02/25/2023] [Indexed: 03/30/2023]
Abstract
Abstract
Background
In a previous study, shaking speed was found to be an important factor affecting the population dynamics and lignocellulose-degrading activities of a synthetic lignocellulolytic microbial consortium composed of the bacteria Sphingobacterium paramultivorum w15, Citrobacter freundii so4, and the fungus Coniochaeta sp. 2T2.1. Here, the gene expression profiles of each strain in this consortium were examined after growth at two shaking speeds (180 and 60 rpm) at three time points (1, 5 and 13 days).
Results
The results indicated that, at 60 rpm, C. freundii so4 switched, to a large extent, from aerobic to flexible (aerobic/microaerophilic/anaerobic) metabolism, resulting in continued slow growth till late stage. In addition, Coniochaeta sp. 2T2.1 tended to occur to a larger extent in the hyphal form, with genes encoding adhesion proteins being highly expressed. Much like at 180 rpm, at 60 rpm, S. paramultivorum w15 and Coniochaeta sp. 2T2.1 were key players in hemicellulose degradation processes, as evidenced from the respective CAZy-specific transcripts. Coniochaeta sp. 2T2.1 exhibited expression of genes encoding arabinoxylan-degrading enzymes (i.e., of CAZy groups GH10, GH11, CE1, CE5 and GH43), whereas, at 180 rpm, some of these genes were suppressed at early stages of growth. Moreover, C. freundii so4 stably expressed genes that were predicted to encode proteins with (1) β-xylosidase/β-glucosidase and (2) peptidoglycan/chitinase activities, (3) stress response- and detoxification-related proteins. Finally, S. paramultivorum w15 showed involvement in vitamin B2 generation in the early stages across the two shaking speeds, while this role was taken over by C. freundii so4 at late stage at 60 rpm.
Conclusions
We provide evidence that S. paramultivorum w15 is involved in the degradation of mainly hemicellulose and in vitamin B2 production, and C. freundii so4 in the degradation of oligosaccharides or sugar dimers, next to detoxification processes. Coniochaeta sp. 2T2.1 was held to be strongly involved in cellulose and xylan (at early stages), next to lignin modification processes (at later stages). The synergism and alternative functional roles presented in this study enhance the eco-enzymological understanding of the degradation of lignocellulose in this tripartite microbial consortium.
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Horng YT, Dewi Panjaitan NS, Chang HJ, Wei YH, Chien CC, Yang HC, Chang HY, Soo PC. A protein containing the DUF1471 domain regulates biofilm formation and capsule production in Klebsiella pneumoniae. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2022; 55:1246-1254. [PMID: 34924339 DOI: 10.1016/j.jmii.2021.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/08/2021] [Accepted: 11/20/2021] [Indexed: 12/27/2022]
Abstract
BACKGROUND/PURPOSE Biofilms formed by Klebsiella pneumoniae on medical devices increase infection risk. Fimbriae and capsule polysaccharides (CPSs) are important factors involved in biofilm formation. KP1_4563 in K. pneumoniae NTUH-K2044, a small protein containing the DUF1471 domain, was reported to inhibit type 3 fimbriae function. In this study, we aimed to determine whether the KP1_4563 homolog is conserved in each K. pneumoniae isolate and what role it has in Klebsiella biofilms. METHODS The genomes of K. pneumoniae NTUH-K2044, CG43, MGH78578, KPPR1 and STU1 were compared. The KP1_4563 homolog in K. pneumoniae STU1 was named orfX. Biofilms of wild-type and orfX mutant strains from K. pneumoniae STU1 and one clinical isolate, 83535, were quantified. Transcription levels of the type 3 fimbrial genes, mrkA and mrkH, were investigated by RT-qPCR. MrkA of the wild-type and orfX mutant were observed by Western blotting. The morphology of bacterial cells was observed by transmission electron microscopy (TEM). Bacterial CPSs were quantified. RESULTS The gene and upstream region of orfX were conserved among the five K. pneumoniae isolates. Deletion of orfX enhanced Klebsiella biofilm formation. However, the amount of mRNA from mrkA and mrkH and the level of MrkA protein were not different between the wild type and orfX mutant. In contrast, the amount of CPS in orfX mutants was increased, compared to their parental strains, STU1 and 83535. CONCLUSION The role of orfX is speculated to be conserved in most K. pneumoniae isolates. OrfX negatively controlled biofilm formation by reducing CPS, not type 3 fimbriae, production.
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Affiliation(s)
- Yu-Tze Horng
- Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C
| | - Novaria Sari Dewi Panjaitan
- Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C
| | - Hui-Ju Chang
- Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C
| | - Yu-Hong Wei
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan, Taiwan, R.O.C
| | - Chih-Ching Chien
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan, Taiwan, R.O.C
| | - Hung-Chi Yang
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University of Medical Technology, Hsinchu, Taiwan, R.O.C
| | - Heng-Yuan Chang
- School of Post-Baccalaureate Chinese Medicine, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C
| | - Po-Chi Soo
- Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan, R.O.C.
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Kharadi RR, Sundin GW. CsrD regulates amylovoran biosynthesis and virulence in Erwinia amylovora in a novel cyclic-di-GMP dependent manner. MOLECULAR PLANT PATHOLOGY 2022; 23:1154-1169. [PMID: 35396793 PMCID: PMC9276943 DOI: 10.1111/mpp.13217] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Erwinia amylovora is an economically devastating plant pathogen that causes fire blight disease in members of the Rosaceae family, most notably in apple and pear. The exopolysaccharide amylovoran is a pathogenicity determinant in E. amylovora and a major component of the extracellular matrix of biofilms formed within the xylem vasculature of the host plant. The second messenger cyclic-di-GMP (c-di-GMP) has been reported to positively regulate the transcription of amsG (the first gene in the 12-gene amylovoran [ams] biosynthetic operon), thus impacting amylovoran production. However, the regulatory mechanism by which this interaction occurs is largely unknown. Here, we report that c-di-GMP can bind to specific residues in the EAL domain of the E. amylovora protein CsrD. CsrD and RNase E regulate the degradation of the sRNA CsrB in E. amylovora. When CsrD is bound to c-di-GMP, there is an enhancement in the level of RNase E-mediated degradation of CsrB, which then alters amsG transcription. Additionally, csrD was also found to positively contribute to virulence and biofilm formation. We thus present a pathway of conditional regulation of amylovoran production mediated by changing intracellular levels of c-di-GMP, which impacts disease progression.
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Affiliation(s)
- Roshni R. Kharadi
- Department of Plant, Soil and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
| | - George W. Sundin
- Department of Plant, Soil and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
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Woitschach F, Kloss M, Schlodder K, Borck A, Grabow N, Reisinger EC, Sombetzki M. Bacterial Adhesion and Biofilm Formation of Enterococcus faecalis on Zwitterionic Methylmethacrylat and Polysulfones. Front Cell Infect Microbiol 2022; 12:868338. [PMID: 35651751 PMCID: PMC9149206 DOI: 10.3389/fcimb.2022.868338] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/13/2022] [Indexed: 11/29/2022] Open
Abstract
Biofilm-associated implant infections represent a major challenge for healthcare systems around the world due to high patient burden and enormous costs incurred. Enterococcus faecalis (E. faecalis) is the most prevalent enterococcal species identified in biofilm-associated infections. The steadily growing areas of application of implants demand a solution for the control of bacterial infections. Therefore, the development of modified anti-microbial implant materials and the testing of the behavior of different relevant bacterial strains towards them display an indispensable task. Recently, we demonstrated an anti-microbial effect of zwitterionic modified silicone rubber (LSR) against Staphylococcus aureus. The aim of this study was to evaluate bacterial colonization and biofilm formation of another clinically relevant strain, E. faecalis, on this material in comparison to two of the most commonly used thermoplastic polyurethanes (TPUs) and other modified LSR surfaces. By generating growth curves, crystal violet, and fluorescence staining, as well as analyzing the expression of biofilm-associated genes, we demonstrated no anti-microbial activity of the investigated materials against E. faecalis. These results point to the fact that anti-microbial effects of novel implant materials do not always apply across the board to all bacterial strains.
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Affiliation(s)
- Franziska Woitschach
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
| | - Marlen Kloss
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
| | | | - Alexander Borck
- Biotronik SE & Co. KG, Research & Development, Berlin, Germany
| | - Niels Grabow
- Institute for Biomedical Engineering, University Medical Center Rostock, Rostock, Germany
| | - Emil Christian Reisinger
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
| | - Martina Sombetzki
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center, Rostock, Germany
- *Correspondence: Martina Sombetzki,
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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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Woitschach F, Kloss M, Schlodder K, Rabes A, Mörke C, Oschatz S, Senz V, Borck A, Grabow N, Reisinger EC, Sombetzki M. The Use of Zwitterionic Methylmethacrylat Coated Silicone Inhibits Bacterial Adhesion and Biofilm Formation of Staphylococcus aureus. Front Bioeng Biotechnol 2021; 9:686192. [PMID: 34249887 PMCID: PMC8267815 DOI: 10.3389/fbioe.2021.686192] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/01/2021] [Indexed: 02/04/2023] Open
Abstract
In recent decades, biofilm-associated infections have become a major problem in many medical fields, leading to a high burden on patients and enormous costs for the healthcare system. Microbial infestations are caused by opportunistic pathogens which often enter the incision already during implantation. In the subsequently formed biofilm bacteria are protected from the hosts immune system and antibiotic action. Therefore, the development of modified, anti-microbial implant materials displays an indispensable task. Thermoplastic polyurethane (TPU) represents the state-of-the-art material in implant manufacturing. Due to the constantly growing areas of application and the associated necessary adjustments, the optimization of these materials is essential. In the present study, modified liquid silicone rubber (LSR) surfaces were compared with two of the most commonly used TPUs in terms of bacterial colonization and biofilm formation. The tests were conducted with the clinically relevant bacterial strains Staphylococcus aureus and Staphylococcus epidermidis. Crystal violet staining and scanning electron microscopy showed reduced adhesion of bacteria and thus biofilm formation on these new materials, suggesting that the investigated materials are promising candidates for implant manufacturing.
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Affiliation(s)
- Franziska Woitschach
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center Rostock, Rostock, Germany
| | - Marlen Kloss
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center Rostock, Rostock, Germany
| | | | - Anne Rabes
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center Rostock, Rostock, Germany
| | - Caroline Mörke
- Division of Cardiology, Center of Internal Medicine II, University Medical Center Rostock, Rostock, Germany
| | - Stefan Oschatz
- Institute for Biomedical Engineering, University Medical Center Rostock, Rostock, Germany
| | - Volkmar Senz
- Institute for Biomedical Engineering, University Medical Center Rostock, Rostock, Germany
| | | | - Niels Grabow
- Institute for Biomedical Engineering, University Medical Center Rostock, Rostock, Germany
| | - Emil Christian Reisinger
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center Rostock, Rostock, Germany
| | - Martina Sombetzki
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center Rostock, Rostock, Germany
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Parise MTD, Parise D, Aburjaile FF, Pinto Gomide AC, Kato RB, Raden M, Backofen R, Azevedo VADC, Baumbach J. An Integrated Database of Small RNAs and Their Interplay With Transcriptional Gene Regulatory Networks in Corynebacteria. Front Microbiol 2021; 12:656435. [PMID: 34220744 PMCID: PMC8247434 DOI: 10.3389/fmicb.2021.656435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 05/19/2021] [Indexed: 12/02/2022] Open
Abstract
Small RNAs (sRNAs) are one of the key players in the post-transcriptional regulation of bacterial gene expression. These molecules, together with transcription factors, form regulatory networks and greatly influence the bacterial regulatory landscape. Little is known concerning sRNAs and their influence on the regulatory machinery in the genus Corynebacterium, despite its medical, veterinary and biotechnological importance. Here, we expand corynebacterial regulatory knowledge by integrating sRNAs and their regulatory interactions into the transcriptional regulatory networks of six corynebacterial species, covering four human and animal pathogens, and integrate this data into the CoryneRegNet database. To this end, we predicted sRNAs to regulate 754 genes, including 206 transcription factors, in corynebacterial gene regulatory networks. Amongst them, the sRNA Cd-NCTC13129-sRNA-2 is predicted to directly regulate ydfH, which indirectly regulates 66 genes, including the global regulator glxR in C. diphtheriae. All of the sRNA-enriched regulatory networks of the genus Corynebacterium have been made publicly available in the newest release of CoryneRegNet(www.exbio.wzw.tum.de/coryneregnet/) to aid in providing valuable insights and to guide future experiments.
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Affiliation(s)
- Mariana Teixeira Dornelles Parise
- Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, Munich, Germany.,Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Doglas Parise
- Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, Munich, Germany.,Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | | | - Rodrigo Bentes Kato
- Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Martin Raden
- Bioinformatics, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | - Rolf Backofen
- Bioinformatics, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | | | - Jan Baumbach
- Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, Munich, Germany.,Computational Biomedicine Lab, Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark.,Chair of Computational Systems Biology, University of Hamburg, Hamburg, Germany
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Multiple Drug-Induced Stress Responses Inhibit Formation of Escherichia coli Biofilms. Appl Environ Microbiol 2020; 86:AEM.01113-20. [PMID: 32826218 PMCID: PMC7580552 DOI: 10.1128/aem.01113-20] [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: 05/11/2020] [Accepted: 08/08/2020] [Indexed: 02/07/2023] Open
Abstract
The prevention of bacterial biofilm formation is one of the major current challenges in microbiology. Here, by systematically screening a large number of approved drugs for their ability to suppress biofilm formation by Escherichia coli, we identified a number of prospective antibiofilm compounds. We further demonstrated different mechanisms of action for individual compounds, from induction of replicative stress to disbalance of cation homeostasis to inhibition of bacterial attachment to the surface. Our work demonstrates the potential of drug repurposing for the prevention of bacterial biofilm formation and suggests that also for other bacteria, the activity spectrum of antibiofilm compounds is likely to be broad. In most ecosystems, bacteria exist primarily as structured surface-associated biofilms that can be highly tolerant to antibiotics and thus represent an important health issue. Here, we explored drug repurposing as a strategy to identify new antibiofilm compounds, screening over 1,000 compounds from the Prestwick Chemical Library of approved drugs for specific activities that prevent biofilm formation by Escherichia coli. Most growth-inhibiting compounds, which include known antibacterial but also antiviral and other drugs, also reduced biofilm formation. However, we also identified several drugs that were biofilm inhibitory at doses where only a weak effect or no effect on planktonic growth could be observed. The activities of the most specific antibiofilm compounds were further characterized using gene expression analysis, proteomics, and microscopy. We observed that most of these drugs acted by repressing genes responsible for the production of curli, a major component of the E. coli biofilm matrix. This repression apparently occurred through the induction of several different stress responses, including DNA and cell wall damage, and homeostasis of divalent cations, demonstrating that biofilm formation can be inhibited through a variety of molecular mechanisms. One tested drug, tyloxapol, did not affect curli expression or cell growth but instead inhibited biofilm formation by suppressing bacterial attachment to the surface. IMPORTANCE The prevention of bacterial biofilm formation is one of the major current challenges in microbiology. Here, by systematically screening a large number of approved drugs for their ability to suppress biofilm formation by Escherichia coli, we identified a number of prospective antibiofilm compounds. We further demonstrated different mechanisms of action for individual compounds, from induction of replicative stress to disbalance of cation homeostasis to inhibition of bacterial attachment to the surface. Our work demonstrates the potential of drug repurposing for the prevention of bacterial biofilm formation and suggests that also for other bacteria, the activity spectrum of antibiofilm compounds is likely to be broad.
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Yu L, Li W, Liu Z, Yu J, Wang W, Shang F, Xue T. Role of McbR in the regulation of antibiotic susceptibility in avian pathogenic Escherichia coli. Poult Sci 2020; 99:6390-6401. [PMID: 33248554 PMCID: PMC7705038 DOI: 10.1016/j.psj.2020.09.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/10/2020] [Accepted: 09/15/2020] [Indexed: 11/16/2022] Open
Abstract
Avian pathogenic Escherichia coli (APEC) causes a variety of bacterial infectious diseases known as avian colibacillosis leading to significant economic losses in the poultry industry worldwide and restricting the development of the poultry industry. The development of efflux pumps is one important bacterial antibiotic resistance mechanism. Efflux pumps are capable of extruding a wide range of antibiotics out of the cytoplasm of some bacterial species, including β-lactams, polymyxins, tetracyclines, fluoroquinolones, aminoglycosides, novobiocin, nalidixic acid, and fosfomycin. In the present study, we constructed the mcbR mutant and the mcbR-overexpressing strain of E. coli strain APECX40 and performed antimicrobial susceptibility testing, antibacterial activity assays, real-time reverse transcription PCR, and electrophoretic mobility shift assays (EMSA) to investigate the molecular regulatory mechanism of McbR on the genes encoding efflux pumps. Our results showed that McbR positively regulates cell susceptibility to 12 antibiotics, including clindamycin, lincomycin, cefotaxime, cefalexin, doxycycline, tetracycline, gentamicin, kanamycin, norfloxacin, ofloxacin, erythromycin, and rifampicin by activating the transcription of acrAB, acrD, emrD, and mdtD (P < 0.01). Additionally, EMSA indicated that McbR specifically binds to the promoter regions of acrAB, acrD, acrR, emrD, and mdtD. This study suggests that, in APECX40, McbR plays an important role in the regulation of bacterial susceptibility by directly activating the transcription of efflux pumps genes.
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Affiliation(s)
- Lumin Yu
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China; Institute of Microbe and Host Health, Linyi University, Linyi, Shandong 276005, China.
| | - Wenchang Li
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Zhichao Liu
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Jiangliu Yu
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Wenhui Wang
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Fei Shang
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China.
| | - Ting Xue
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China.
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12
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Pobeguts OV, Ladygina VG, Evsyutina DV, Eremeev AV, Zubov AI, Matyushkina DS, Scherbakov PL, Rakitina DV, Fisunov GY. Propionate Induces Virulent Properties of Crohn's Disease-Associated Escherichia coli. Front Microbiol 2020; 11:1460. [PMID: 32733408 PMCID: PMC7360682 DOI: 10.3389/fmicb.2020.01460] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 06/04/2020] [Indexed: 12/16/2022] Open
Abstract
Crohn's disease (CD) is a severe chronic immune-mediated granulomatous inflammatory disease of the gastrointestinal tract. The mechanisms of CD pathogenesis remain obscure. Metagenomic analysis of samples from CD patients revealed that several of them have the elevated level of Escherichia coli with adhesive-invasive phenotype (AIEC). Previously, we isolated an E. coli strain CD isolate ZvL2 from a patient with CD, which features AIEC phenotype. Here, we demonstrate that prolonged growth on propionate containing medium stimulates virulent properties of CD isolate ZvL2, while prolonged growth on glucose reduces these properties to levels indistinguishable from laboratory strain K-12 MG1655. Propionate presence also boosts the ability of CD isolate ZvL2 to penetrate and colonize macrophages. The effect of propionate is reversible, re-passaging of CD isolate on M9 medium supplemented with glucose leads to the loss of its virulent properties. Proteome analysis of CD isolate ZvL2 growth in medium supplemented with propionate or glucose revealed that propionate induces expression porins OmpA and OmpW, transcription factors PhoP and OmpR, and universal stress protein UspE, which were previously found to be important for macrophage colonization by enteropathogenic bacteria.
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Affiliation(s)
- Olga V. Pobeguts
- Department of Molecular Biology and Genetics, Federal Research and Clinical Centre of Physical and Chemical Medicine, Federal Medical-Biological Agency, Moscow, Russia
| | - Valentina G. Ladygina
- Department of Molecular Biology and Genetics, Federal Research and Clinical Centre of Physical and Chemical Medicine, Federal Medical-Biological Agency, Moscow, Russia
| | - Daria V. Evsyutina
- Department of Molecular Biology and Genetics, Federal Research and Clinical Centre of Physical and Chemical Medicine, Federal Medical-Biological Agency, Moscow, Russia
| | - Artem V. Eremeev
- Department of Molecular Biology and Genetics, Federal Research and Clinical Centre of Physical and Chemical Medicine, Federal Medical-Biological Agency, Moscow, Russia
| | - Aleksandr I. Zubov
- Department of Molecular Biology and Genetics, Federal Research and Clinical Centre of Physical and Chemical Medicine, Federal Medical-Biological Agency, Moscow, Russia
| | - Daria S. Matyushkina
- Department of Molecular Biology and Genetics, Federal Research and Clinical Centre of Physical and Chemical Medicine, Federal Medical-Biological Agency, Moscow, Russia
| | | | - Daria V. Rakitina
- Department of Molecular Biology and Genetics, Federal Research and Clinical Centre of Physical and Chemical Medicine, Federal Medical-Biological Agency, Moscow, Russia
| | - Gleb Y. Fisunov
- Department of Molecular Biology and Genetics, Federal Research and Clinical Centre of Physical and Chemical Medicine, Federal Medical-Biological Agency, Moscow, Russia
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13
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Chen Y, Boggess EE, Ocasio ER, Warner A, Kerns L, Drapal V, Gossling C, Ross W, Gourse RL, Shao Z, Dickerson J, Mansell TJ, Jarboe LR. Reverse engineering of fatty acid-tolerant Escherichia coli identifies design strategies for robust microbial cell factories. Metab Eng 2020; 61:120-130. [PMID: 32474056 DOI: 10.1016/j.ymben.2020.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 02/05/2020] [Accepted: 05/02/2020] [Indexed: 10/24/2022]
Abstract
Adaptive laboratory evolution is often used to improve the performance of microbial cell factories. Reverse engineering of evolved strains enables learning and subsequent incorporation of novel design strategies via the design-build-test-learn cycle. Here, we reverse engineer a strain of Escherichia coli previously evolved for increased tolerance of octanoic acid (C8), an attractive biorenewable chemical, resulting in increased C8 production, increased butanol tolerance, and altered membrane properties. Here, evolution was determined to have occurred first through the restoration of WaaG activity, involved in the production of lipopolysaccharides, then an amino acid change in RpoC, a subunit of RNA polymerase, and finally mutation of the BasS-BasR two component system. All three mutations were required in order to reproduce the increased growth rate in the presence of 20 mM C8 and increased cell surface hydrophobicity; the WaaG and RpoC mutations both contributed to increased C8 titers, with the RpoC mutation appearing to be the major driver of this effect. Each of these mutations contributed to changes in the cell membrane. Increased membrane integrity and rigidity and decreased abundance of extracellular polymeric substances can be attributed to the restoration of WaaG. The increase in average lipid tail length can be attributed to the RpoCH419P mutation, which also confers tolerance to other industrially-relevant inhibitors, such as furfural, vanillin and n-butanol. The RpoCH419P mutation may impact binding or function of the stringent response alarmone ppGpp to RpoC site 1. Each of these mutations provides novel strategies for engineering microbial robustness, particularly at the level of the microbial cell membrane.
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Affiliation(s)
- Yingxi Chen
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Erin E Boggess
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA, 50011, USA; Bioinformatics & Computational Biology Graduate Program, Iowa State University, Ames, IA, 50011, USA
| | - Efrain Rodriguez Ocasio
- NSF Center for Biorenewable Chemicals (CBiRC) Research Experience for Undergraduates, Ames, IA, 50011, USA; Industrial Biotechnology Program, University of Puerto Rico Mayagüez, 00681, Puerto Rico
| | - Aric Warner
- Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, 50011, USA
| | - Lucas Kerns
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Victoria Drapal
- NSF Center for Biorenewable Chemicals (CBiRC) Research Experience for Undergraduates, Ames, IA, 50011, USA; Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68508, USA
| | - Chloe Gossling
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Wilma Ross
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Richard L Gourse
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Zengyi Shao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA; Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, 50011, USA
| | - Julie Dickerson
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA, 50011, USA; Bioinformatics & Computational Biology Graduate Program, Iowa State University, Ames, IA, 50011, USA
| | - Thomas J Mansell
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA; Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, 50011, USA.
| | - Laura R Jarboe
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA; Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, 50011, USA.
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14
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Yu L, Li W, Qi K, Wang S, Chen X, Ni J, Deng R, Shang F, Xue T. McbR is involved in biofilm formation and H2O2 stress response in avian pathogenic Escherichia coli X40. Poult Sci 2019; 98:4094-4103. [PMID: 31002106 DOI: 10.3382/ps/pez205] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/22/2019] [Indexed: 11/20/2022] Open
Abstract
Avian pathogenic Escherichia coli (APEC) causes a variety of extraintestinal diseases known as colibacillosis and is responsible for significant economic losses in the poultry industry worldwide. Biofilm formation results in increased morbidity and persistent infections, and is the main reason for the difficult treatment of colibacillosis with antimicrobial agents. It is reported that the transcriptional regulator McbR regulates biofilm formation and mucoidy by repressing the expression of the periplasmic protein YbiM, and activates the transcription of the yciGFE operon by binding to the yciG promoter in E. coli K-12. However, whether McbR regulates biofilm formation and H2O2 stress response in APEC has been not reported. The present study showed that, in the clinical isolate APECX40, the deletion of mcbR increased biofilm formation by upregulating the transcription of the biofilm-associated genes bcsA, fliC, wcaF, and fimA. In addition, the deletion of mcbR decreased H2O2 stress response by downregulating the transcript levels of the stress-associated genes yciF and yciE. The electrophoretic mobility shift assays confirmed that McbR directly binds to the promoter regions of yciG and yciF. This study may provide new clues to understanding gene regulation in APEC.
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Affiliation(s)
- Lumin Yu
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Wenchang Li
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Kezong Qi
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Hefei, Anhui 230036, China
| | - Siyu Wang
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Xiaolin Chen
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Jingtian Ni
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Ruining Deng
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Fei Shang
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Ting Xue
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
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15
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Pal S, Verma J, Mallick S, Rastogi SK, Kumar A, Ghosh AS. Absence of the glycosyltransferase WcaJ in Klebsiella pneumoniae ATCC13883 affects biofilm formation, increases polymyxin resistance and reduces murine macrophage activation. Microbiology (Reading) 2019; 165:891-904. [PMID: 31246167 DOI: 10.1099/mic.0.000827] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Shilpa Pal
- Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal-721302, India
| | - Jyoti Verma
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, West Bengal-721302, India
| | - Sathi Mallick
- Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal-721302, India
| | - Sumit Kumar Rastogi
- Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal-721302, India
| | - Akash Kumar
- Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal-721302, India
| | - Anindya S. Ghosh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal-721302, India
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16
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Zeng Z, Zhan W, Wang W, Wang P, Tang K, Wang X. Biofilm formation in Pseudoalteromonas lipolytica is related to IS5-like insertions in the capsular polysaccharide operon. FEMS Microbiol Ecol 2019; 95:5488432. [PMID: 31077283 DOI: 10.1093/femsec/fiz065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 05/10/2019] [Indexed: 11/14/2022] Open
Abstract
Bacterial capsular polysaccharides (CPSs) participate in environmental adaptation in diverse bacteria species. However, the role and regulation of CPS production in marine bacteria have remained largely unexplored. We previously reported that both wrinkled and translucent Pseudoalteromonas lipolytica variants with altered polysaccharide production were generated in pellicle biofilm-associated cells. In this study, we observed that translucent variants were generated at a rate of ∼20% in colony biofilms of P. lipolytica cultured on HSLB agar plates for 12 days. The DNA sequencing results revealed that nearly 90% of these variants had an IS5-like element inserted within the coding or promoter regions of nine genes in the cps operon. In contrast, IS5 insertion into the cps operon was not detected in planktonic cells. Furthermore, we demonstrated that the IS5 insertion event inactivated CPS production, which leads to a translucent colony morphology. The CPS-deficient variants showed an increased ability to form attached biofilms but exhibited reduced resistance to sublethal concentrations of antibiotics. Moreover, deleting the DNA repair gene recA significantly decreased the frequency of occurrence of CPS-deficient variants during biofilm formation. Thus, IS insertion into the cps operon is an important mechanism for the production of genetic variants during biofilm formation of marine bacteria.
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Affiliation(s)
- Zhenshun Zeng
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Waner Zhan
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weiquan Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pengxia Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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17
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Metabolome and transcriptome-wide effects of the carbon storage regulator A in enteropathogenic Escherichia coli. Sci Rep 2019; 9:138. [PMID: 30644424 PMCID: PMC6333774 DOI: 10.1038/s41598-018-36932-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 11/28/2018] [Indexed: 02/06/2023] Open
Abstract
The carbon storage regulator A (CsrA) is a conserved global regulatory system known to control central carbon pathways, biofilm formation, motility, and pathogenicity. The aim of this study was to characterize changes in major metabolic pathways induced by CsrA in human enteropathogenic Escherichia coli (EPEC) grown under virulence factor-inducing conditions. For this purpose, the metabolomes and transcriptomes of EPEC and an isogenic ∆csrA mutant derivative were analyzed by untargeted mass spectrometry and RNA sequencing, respectively. Of the 159 metabolites identified from untargeted GC/MS and LC/MS data, 97 were significantly (fold change ≥ 1.5; corrected p-value ≤ 0.05) regulated between the knockout and the wildtype strain. A lack of csrA led to an accumulation of fructose-6-phosphate (F6P) and glycogen synthesis pathway products, whereas metabolites in lower glycolysis and the citric acid cycle were downregulated. Associated pathways from the citric acid cycle like aromatic amino acid and siderophore biosynthesis were also negatively influenced. The nucleoside salvage pathways were featured by an accumulation of nucleosides and nucleobases, and a downregulation of nucleotides. In addition, a pronounced downregulation of lyso-lipid metabolites was observed. A drastic change in the morphology in the form of vesicle-like structures of the ∆csrA knockout strain was visible by electron microscopy. Colanic acid synthesis genes were strongly (up to 50 fold) upregulated, and the abundance of colanic acid was 3 fold increased according to a colorimetric assay. The findings expand the scope of pathways affected by the csrA regulon and emphasize its importance as a global regulator.
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18
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The bile salt glycocholate induces global changes in gene and protein expression and activates virulence in enterotoxigenic Escherichia coli. Sci Rep 2019; 9:108. [PMID: 30643184 PMCID: PMC6331568 DOI: 10.1038/s41598-018-36414-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 11/20/2018] [Indexed: 12/23/2022] Open
Abstract
Pathogenic bacteria use specific host factors to modulate virulence and stress responses during infection. We found previously that the host factor bile and the bile component glyco-conjugated cholate (NaGCH, sodium glycocholate) upregulate the colonization factor CS5 in enterotoxigenic Escherichia coli (ETEC). To further understand the global regulatory effects of bile and NaGCH, we performed Illumina RNA-Seq and found that crude bile and NaGCH altered the expression of 61 genes in CS5 + CS6 ETEC isolates. The most striking finding was high induction of the CS5 operon (csfA-F), its putative transcription factor csvR, and the putative ETEC virulence factor cexE. iTRAQ-coupled LC-MS/MS proteomic analyses verified induction of the plasmid-borne virulence proteins CS5 and CexE and also showed that NaGCH affected the expression of bacterial membrane proteins. Furthermore, NaGCH induced bacteria to aggregate, increased their adherence to epithelial cells, and reduced their motility. Our results indicate that CS5 + CS6 ETEC use NaGCH present in the small intestine as a signal to initiate colonization of the epithelium.
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19
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Abstract
SixA, a well-conserved protein found in proteobacteria, actinobacteria, and cyanobacteria, is the only reported example of a bacterial phosphohistidine phosphatase. A single protein target of SixA has been reported to date: the Escherichia coli histidine kinase ArcB. The present work analyzes an ArcB-independent growth defect of a sixA deletion in E. coli A screen for suppressors, analysis of various mutants, and phosphorylation assays indicate that SixA modulates phosphorylation of the nitrogen-related phosphotransferase system (PTSNtr). The PTSNtr is a widely conserved bacterial pathway that regulates diverse metabolic processes through the phosphorylation states of its protein components, EINtr, NPr, and EIIANtr, which receive phosphoryl groups on histidine residues. However, a mechanism for dephosphorylating this system has not been reported. The results presented here suggest a model in which SixA removes phosphoryl groups from the PTSNtr by acting on NPr. This work uncovers a new role for the phosphohistidine phosphatase SixA and, through factors that affect SixA expression or activity, may point to additional inputs that regulate the PTSNtr IMPORTANCE One common means to regulate protein activity is through phosphorylation. Protein phosphatases exist to reverse this process, returning the protein to the unphosphorylated form. The vast majority of protein phosphatases that have been identified target phosphoserine, phosphotheronine, and phosphotyrosine. A widely conserved phosphohistidine phosphatase was identified in Escherichia coli 20 years ago but remains relatively understudied. The present work shows that this phosphatase modulates the nitrogen-related phosphotransferase system, a pathway that is regulated by nitrogen and carbon metabolism and affects diverse aspects of bacterial physiology. Until now, there was no known mechanism for removing phosphoryl groups from this pathway.
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20
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Harris S, Piotrowska MJ, Goldstone RJ, Qi R, Foster G, Dobrindt U, Madec JY, Valat C, Rao FV, Smith DGE. Variant O89 O-Antigen of E. coli Is Associated With Group 1 Capsule Loci and Multidrug Resistance. Front Microbiol 2018; 9:2026. [PMID: 30233517 PMCID: PMC6128206 DOI: 10.3389/fmicb.2018.02026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/09/2018] [Indexed: 11/13/2022] Open
Abstract
Bacterial surface polysaccharides play significant roles in fitness and virulence. In Gram-negative bacteria such as Escherichia coli, major surface polysaccharides are lipopolysaccharide (LPS) and capsule, representing O- and K-antigens, respectively. There are multiple combinations of O:K types, many of which are well-characterized and can be related to ecotype or pathotype. In this investigation, we have identified a novel O:K permutation resulting through a process of major genome reorganization in a clade of E. coli. A multidrug-resistant, extended-spectrum β-lactamase (ESBL)-producing strain - E. coli 26561 - represented a prototype of strains combining a locus variant of O89 and group 1 capsular polysaccharide. Specifically, the variant O89 locus in this strain was truncated at gnd, flanked by insertion sequences and located between nfsB and ybdK and we apply the term O89m for this variant. The prototype lacked colanic acid and O-antigen loci between yegH and hisI with this tandem polysaccharide locus being replaced with a group 1 capsule (G1C) which, rather than being a recognized E. coli capsule type, this locus matched to Klebsiella K10 capsule type. A genomic survey identified more than 200 E. coli strains which possessed the O89m locus variant with one of a variety of G1C types. Isolates from our collection with the combination of O89m and G1C all displayed a mucoid phenotype and E. coli 26561 was unusual in exhibiting a mucoviscous phenotype more recognized as a characteristic among Klebsiella strains. Despite the locus truncation and novel location, all O89m:G1C strains examined showed a ladder pattern typifying smooth LPS and also showed high molecular weight, alcian blue-staining polysaccharide in cellular and/or extra-cellular fractions. Expression of both O-antigen and capsule biosynthesis loci were confirmed in prototype strain 26561 through quantitative proteome analysis. Further in silico exploration of more than 200 E. coli strains possessing the O89m:G1C combination identified a very high prevalence of multidrug resistance (MDR) - 85% possessed resistance to three or more antibiotic classes and a high proportion (58%) of these carried ESBL and/or carbapenemase. The increasing isolation of O89m:G1C isolates from extra-intestinal infection sites suggests that these represents an emergent clade of invasive, MDR E. coli.
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Affiliation(s)
- Susan Harris
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | - Marta J Piotrowska
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | | | - Ruby Qi
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | - Geoffrey Foster
- Veterinary Services, SAC Consulting, Scotland's Rural College, Inverness, United Kingdom
| | - Ulrich Dobrindt
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Jean-Yves Madec
- Unité Antibiorésistances et Virulences Bactériennes, Anses Laboratoire de Lyon, Université Lyon-1, Lyon, France
| | - Charlotte Valat
- Unité Antibiorésistances et Virulences Bactériennes, Anses Laboratoire de Lyon, Université Lyon-1, Lyon, France
| | | | - David G E Smith
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
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21
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Coordinated Hibernation of Transcriptional and Translational Apparatus during Growth Transition of Escherichia coli to Stationary Phase. mSystems 2018; 3:mSystems00057-18. [PMID: 30225374 PMCID: PMC6134199 DOI: 10.1128/msystems.00057-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 08/06/2018] [Indexed: 12/14/2022] Open
Abstract
During the growth transition of E. coli from exponential phase to stationary, the genome expression pattern is altered markedly. For this alteration, the transcription apparatus is altered by binding of anti-sigma factor Rsd to the RpoD sigma factor for sigma factor replacement, while the translation machinery is modulated by binding of RMF to 70S ribosome to form inactive ribosome dimer. Using the PS-TF screening system, a number of TFs were found to bind to both the rsd and rmf promoters, of which the regulatory roles of 5 representative TFs (one repressor ArcA and the four activators McbR, RcdA, SdiA, and SlyA) were analyzed in detail. The results altogether indicated the involvement of a common set of TFs, each sensing a specific environmental condition, in coordinated hibernation of the transcriptional and translational apparatus for adaptation and survival under stress conditions. In the process of Escherichia coli K-12 growth from exponential phase to stationary, marked alteration takes place in the pattern of overall genome expression through modulation of both parts of the transcriptional and translational apparatus. In transcription, the sigma subunit with promoter recognition properties is replaced from the growth-related factor RpoD by the stationary-phase-specific factor RpoS. The unused RpoD is stored by binding with the anti-sigma factor Rsd. In translation, the functional 70S ribosome is converted to inactive 100S dimers through binding with the ribosome modulation factor (RMF). Up to the present time, the regulatory mechanisms of expression of these two critical proteins, Rsd and RMF, have remained totally unsolved. In this study, attempts were made to identify the whole set of transcription factors involved in transcription regulation of the rsd and rmf genes using the newly developed promoter-specific transcription factor (PS-TF) screening system. In the first screening, 74 candidate TFs with binding activity to both of the rsd and rmf promoters were selected from a total of 194 purified TFs. After 6 cycles of screening, we selected 5 stress response TFs, ArcA, McbR, RcdA, SdiA, and SlyA, for detailed analysis in vitro and in vivo of their regulatory roles. Results indicated that both rsd and rmf promoters are repressed by ArcA and activated by McbR, RcdA, SdiA, and SlyA. We propose the involvement of a number of TFs in simultaneous and coordinated regulation of the transcriptional and translational apparatus. By using genomic SELEX (gSELEX) screening, each of the five TFs was found to regulate not only the rsd and rmf genes but also a variety of genes for growth and survival. IMPORTANCE During the growth transition of E. coli from exponential phase to stationary, the genome expression pattern is altered markedly. For this alteration, the transcription apparatus is altered by binding of anti-sigma factor Rsd to the RpoD sigma factor for sigma factor replacement, while the translation machinery is modulated by binding of RMF to 70S ribosome to form inactive ribosome dimer. Using the PS-TF screening system, a number of TFs were found to bind to both the rsd and rmf promoters, of which the regulatory roles of 5 representative TFs (one repressor ArcA and the four activators McbR, RcdA, SdiA, and SlyA) were analyzed in detail. The results altogether indicated the involvement of a common set of TFs, each sensing a specific environmental condition, in coordinated hibernation of the transcriptional and translational apparatus for adaptation and survival under stress conditions.
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22
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Pu M, Sheng L, Song S, Gong T, Wood TK. Serine Hydroxymethyltransferase ShrA (PA2444) Controls Rugose Small-Colony Variant Formation in Pseudomonas aeruginosa. Front Microbiol 2018. [PMID: 29535691 PMCID: PMC5835335 DOI: 10.3389/fmicb.2018.00315] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Pseudomonas aeruginosa causes many biofilm infections, and the rugose small-colony variants (RSCVs) of this bacterium are important for infection. We found here that inactivation of PA2444, which we determined to be a serine hydroxymethyltransferase (SHMT), leads to the RSCV phenotype of P. aeruginosa PA14. In addition, loss of PA2444 increases biofilm formation by two orders of magnitude, increases exopolysaccharide by 45-fold, and abolishes swarming. The RSCV phenotype is related to higher cyclic diguanylate concentrations due to increased activity of the Wsp chemosensory system, including diguanylate cyclase WspR. By characterizing the PA2444 enzyme in vitro, we determined the physiological function of PA2444 protein by relating it to S-adenosylmethionine (SAM) concentrations and methylation of a membrane bound methyl-accepting chemotaxis protein WspA. A whole transcriptome analysis also revealed PA2444 is related to the redox state of the cells, and the altered redox state was demonstrated by an increase in the intracellular NADH/NAD+ ratio. Hence, we provide a mechanism for how an enzyme of central metabolism controls the community behavior of the bacterium, and suggest the PA2444 protein should be named ShrA for serine hydroxymethyltransferase related to rugose colony formation.
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Affiliation(s)
- Mingming Pu
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Lili Sheng
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Sooyeon Song
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Ting Gong
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, United States
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23
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Poosarla VG, Wood TL, Zhu L, Miller DS, Yin B, Wood TK. Dispersal and inhibitory roles of mannose, 2-deoxy-d-glucose and N-acetylgalactosaminidase on the biofilm of Desulfovibrio vulgaris. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:779-787. [PMID: 28925553 DOI: 10.1111/1758-2229.12595] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 09/14/2017] [Indexed: 06/07/2023]
Abstract
Biofilms of sulfate-reducing bacteria (SRB) are often the major cause of microbiologically influenced corrosion. The representative SRB Desulfovibrio vulgaris has previously been shown to have a biofilm that consists primarily of protein. In this study, by utilizing lectin staining, we identified that the biofilm of D. vulgaris also consists of the matrix components mannose, fucose and N-acetylgalactosamine (GalNAc), with mannose predominating. Based on these results, we found that the addition of mannose and the nonmetabolizable mannose analog 2-deoxy-d-glucose inhibits the biofilm formation of D. vulgaris as well as that of D. desulfuricans; both compounds also dispersed the SRB biofilms. In addition, the enzyme N-acetylgalactosaminidase, which degrades GalNAc, was effective in dispersing D. vulgaris biofilms. Therefore, by determining composition of the SRB biofilm, effective biofilm control methods may be devised.
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Affiliation(s)
- Venkata G Poosarla
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Thammajun L Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Lei Zhu
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Daniel S Miller
- Dow Microbial Control, Dow Chemical Company, Collegeville, PA 19426, USA
| | - Bei Yin
- Dow Microbial Control, Dow Chemical Company, Collegeville, PA 19426, USA
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, USA
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
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24
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Uhlich GA, Chen CY, Cottrell BJ, Andreozzi E, Irwin PL, Nguyen LH. Genome amplification and promoter mutation expand the range of csgD-dependent biofilm responses in an STEC population. MICROBIOLOGY-SGM 2017; 163:611-621. [PMID: 28406080 DOI: 10.1099/mic.0.000448] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Expression of the major biofilm components of E. coli, curli fimbriae and cellulose, requires the CsgD transcription factor. A complex regulatory network allows environmental control of csgD transcription and biofilm formation. However, most clinical serotype O157 : H7 strains contain prophage insertions in the csgD regulator, mlrA, or mutations in other regulators that restrict csgD expression. These barriers can be circumvented by certain compensating mutations that restore higher csgD expression. One mechanism is via csgD promoter mutations that switch sigma factor utilization. Biofilm-forming variants utilizing RpoD rather than RpoS have been identified in glycerol freezer stocks of the non-biofilm-forming food-borne outbreak strain, ATCC 43894. In this study we used whole genome sequencing and RNA-seq to study genotypic and transcriptomic differences between those strains. In addition to defining the consequences of the csgD promoter switch and identifying new csgD-controlled genes, we discovered a region of genome amplification in our laboratory stock of 43894 (designated 43894OW) that contributed to the regulation of csgD-dependent properties.
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Affiliation(s)
- Gaylen A Uhlich
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA, USA
| | - Chin-Yi Chen
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA, USA
| | - Bryan J Cottrell
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA, USA
| | - Elisa Andreozzi
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA, USA
| | - Peter L Irwin
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA, USA
| | - Ly-Huong Nguyen
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA, USA
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25
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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: 75] [Impact Index Per Article: 9.4] [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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26
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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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27
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Su HZ, Wu L, Qi YH, Liu GF, Lu GT, Tang JL. Characterization of the GntR family regulator HpaR1 of the crucifer black rot pathogen Xanthomonas campestris pathovar campestris. Sci Rep 2016; 6:19862. [PMID: 26818230 PMCID: PMC4730234 DOI: 10.1038/srep19862] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/17/2015] [Indexed: 01/05/2023] Open
Abstract
The GntR family transcription regulator HpaR1 identified from Xanthomonas campestris pv. campestris has been previously shown to positively regulate the genes responsible for hypersensitive reaction and pathogenicity and to autorepress its own expression. Here, we demonstrated that HpaR1 is a global regulator that positively regulates diverse biological processes, including xanthan polysaccharide production, extracellular enzyme activity, cell motility and tolerance to various stresses. To investigate the regulatory mechanisms of HpaR1, we began with xanthan polysaccharide production, which is governed by a cluster of gum genes. These are directed by the gumB promoter. Disruption of HpaR1 significantly reduced gumB transcription and an electrophoretic mobility shift assay demonstrated that HpaR1 interacts directly with gumB promoter. DNase I footprint analysis revealed that HpaR1 and RNA polymerase were bound to the sequences extending from −21 to +10 and −41 to +29 relative to the transcription initiation site of gumB, respectively. Furthermore, in vitro transcription assays showed that HpaR1 facilitated the binding of RNA polymerase to gumB promoter, leading to an enhancement of its transcription. These results suggest that HpaR1 regulates gumB transcription via a mechanism similar but different to what was found, until now, to only be used by some MerR family transcription activators.
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Affiliation(s)
- Hui-Zhao Su
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
| | - Liu Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
| | - Yan-Hua Qi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
| | - Guo-Fang Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
| | - Guang-Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
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28
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Zeng Z, Guo XP, Li B, Wang P, Cai X, Tian X, Zhang S, Yang JL, Wang X. Characterization of self-generated variants in Pseudoalteromonas lipolytica biofilm with increased antifouling activities. Appl Microbiol Biotechnol 2015; 99:10127-39. [PMID: 26264135 PMCID: PMC4643108 DOI: 10.1007/s00253-015-6865-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/08/2015] [Accepted: 07/20/2015] [Indexed: 02/04/2023]
Abstract
Pseudoalteromonas is widespread in various marine environments, and most strains can affect invertebrate larval settlement and metamorphosis by forming biofilms. However, the impact and the molecular basis of population diversification occurring in Pseudoalteromonas biofilms are poorly understood. Here, we show that morphological diversification is prevalent in Pseudoalteromonas species during biofilm formation. Two types of genetic variants, wrinkled (frequency of 12 ± 5 %) and translucent (frequency of 5 ± 3 %), were found in Pseudoalteromonas lipolytica biofilms. The inducing activities of biofilms formed by the two variants on larval settlement and metamorphosis of the mussel Mytilus coruscus were significantly decreased, suggesting strong antifouling activities. Using whole-genome re-sequencing combined with genetic manipulation, two genes were identified to be responsible for the morphology alternations. A nonsense mutation in AT00_08765 led to a wrinkled morphology due to the overproduction of cellulose, whereas a point mutation in AT00_17125 led to a translucent morphology via a reduction in capsular polysaccharide production. Taken together, the results suggest that the microbial behavior on larval settlement and metamorphosis in marine environment could be affected by the self-generated variants generated during the formation of marine biofilms, thereby rendering potential application in biocontrol of marine biofouling.
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Affiliation(s)
- Zhenshun Zeng
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | | | - Baiyuan Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Pengxia Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, People's Republic of China
| | - Xingsheng Cai
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, People's Republic of China
| | - Xinpeng Tian
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, People's Republic of China
| | - Si Zhang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, People's Republic of China
| | | | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, People's Republic of China.
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29
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Vadyvaloo V, Viall AK, Jarrett CO, Hinz AK, Sturdevant DE, Joseph Hinnebusch B. Role of the PhoP-PhoQ gene regulatory system in adaptation of Yersinia pestis to environmental stress in the flea digestive tract. MICROBIOLOGY-SGM 2015; 161:1198-1210. [PMID: 25804213 PMCID: PMC4635514 DOI: 10.1099/mic.0.000082] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Yersinia pestis PhoPQ gene regulatory system is induced during infection of the flea digestive tract and is required to produce adherent biofilm in the foregut, which greatly enhances bacterial transmission during a flea bite. To understand the in vivo context of PhoPQ induction and to determine PhoP-regulated targets in the flea, we undertook whole-genome comparative transcriptional profiling of Y. pestis WT and ΔphoP strains isolated from infected fleas and from temperature-matched in vitro planktonic and flow-cell biofilm cultures. In the absence of PhoP regulation, the gene expression program indicated that the bacteria experienced diverse physiological stresses and were in a metabolically less active state. Multiple stress response genes, including several toxin–antitoxin loci and YhcN family genes responsible for increased acid tolerance, were upregulated in the phoP mutant during flea infection. The data implied that PhoPQ was induced by low pH in the flea gut, and that PhoP modulated physiological adaptation to acid and other stresses encountered during infection of the flea. This adaptive response, together with PhoP-dependent modification of the bacterial outer surface that includes repression of pH 6 antigen fimbriae, supports stable biofilm development in the flea foregut.
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Affiliation(s)
- Viveka Vadyvaloo
- 1Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, 99164, USA
| | - Austin K Viall
- 2Plague Section, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Clayton O Jarrett
- 2Plague Section, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Angela K Hinz
- 1Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, 99164, USA
| | - Daniel E Sturdevant
- 3Genomics Unit, Research Technologies Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - B Joseph Hinnebusch
- 2Plague Section, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
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30
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Köseoğlu VK, Heiss C, Azadi P, Topchiy E, Güvener ZT, Lehmann TE, Miller KW, Gomelsky M. Listeria monocytogenes exopolysaccharide: origin, structure, biosynthetic machinery and c-di-GMP-dependent regulation. Mol Microbiol 2015; 96:728-43. [PMID: 25662512 DOI: 10.1111/mmi.12966] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2015] [Indexed: 12/21/2022]
Abstract
Elevated levels of the second messenger c-di-GMP activate biosynthesis of an unknown exopolysaccharide (EPS) in the food-borne pathogen Listeria monocytogenes. This EPS strongly protects cells against disinfectants and desiccation, indicating its potential significance for listerial persistence in the environment and for food safety. We analyzed the potential phylogenetic origin of this EPS, determined its complete structure, characterized genes involved in its biosynthesis and hydrolysis and identified diguanylate cyclases activating its synthesis. Phylogenetic analysis of EPS biosynthesis proteins suggests that they have evolved within monoderms. Scanning electron microscopy revealed that L. monocytogenes EPS is cell surface-bound. Secreted carbohydrates represent exclusively cell-wall debris. Based on carbohydrate composition, linkage and NMR analysis, the structure of the purified EPS is identified as a β-1,4-linked N-acetylmannosamine chain decorated with terminal α-1,6-linked galactose. All genes of the pssA-E operon are required for EPS production and so is a separately located pssZ gene. We show that PssZ has an EPS-specific glycosylhydrolase activity. Exogenously added PssZ prevents EPS-mediated cell aggregation and disperses preformed aggregates, whereas an E72Q mutant in the presumed catalytic residue is much less active. The diguanylate cyclases DgcA and DgcB, whose genes are located next to pssZ, are primarily responsible for c-di-GMP-dependent EPS production.
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Affiliation(s)
- Volkan K Köseoğlu
- Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA
| | - Christian Heiss
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, 30602, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, 30602, USA
| | - Elena Topchiy
- Department of Chemistry, University of Wyoming, Laramie, WY, 82071, USA
| | - Zehra T Güvener
- Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA
| | - Teresa E Lehmann
- Department of Chemistry, University of Wyoming, Laramie, WY, 82071, USA
| | - Kurt W Miller
- Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA
| | - Mark Gomelsky
- Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA
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31
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Transcriptional responses to sucrose mimic the plant-associated life style of the plant growth promoting endophyte Enterobacter sp. 638. PLoS One 2015; 10:e0115455. [PMID: 25607953 PMCID: PMC4301647 DOI: 10.1371/journal.pone.0115455] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 11/24/2014] [Indexed: 11/19/2022] Open
Abstract
Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involved in motility (e.g. flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability.
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32
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Phage-encoded colanic acid-degrading enzyme permits lytic phage infection of a capsule-forming resistant mutant Escherichia coli strain. Appl Environ Microbiol 2014; 81:900-9. [PMID: 25416767 DOI: 10.1128/aem.02606-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In this study, we isolated a bacteriophage T7-resistant mutant strain of Escherichia coli (named S3) and then proceeded to characterize it. The mutant bacterial colonies appeared to be mucoid. Microarray analysis revealed that genes related to colanic acid production were upregulated in the mutant. Increases in colanic acid production by the mutant bacteria were observed when l-fucose was measured biochemically, and protective capsule formation was observed under an electron microscope. We found a point mutation in the lon gene promoter in S3, the mutant bacterium. Overproduction of colanic acid was observed in some phage-resistant mutant bacteria after infection with other bacteriophages, T4 and lambda. Colanic acid overproduction was also observed in clinical isolates of E. coli upon phage infection. The overproduction of colanic acid resulted in the inhibition of bacteriophage adsorption to the host. Biofilm formation initially decreased shortly after infection but eventually increased after 48 h of incubation due to the emergence of the mutant bacteria. Bacteriophage PBECO4 was shown to infect the colanic acid-overproducing mutant strains of E. coli. We confirmed that the gene product of open reading frame 547 (ORF547) of PBECO4 harbored colanic acid-degrading enzymatic (CAE) activity. Treatment of the T7-resistant bacteria with both T7 and PBECO4 or its purified enzyme (CAE) led to successful T7 infection. Biofilm formation decreased with the mixed infection, too. This procedure, using a phage cocktail different from those exploiting solely receptor differences, represents a novel strategy for overcoming phage resistance in mutant bacteria.
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33
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Lord DM, Uzgoren Baran A, Soo VWC, Wood TK, Peti W, Page R. McbR/YncC: implications for the mechanism of ligand and DNA binding by a bacterial GntR transcriptional regulator involved in biofilm formation. Biochemistry 2014; 53:7223-31. [PMID: 25376905 PMCID: PMC4245980 DOI: 10.1021/bi500871a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
MqsR-controlled
colanic acid and biofilm regulator (McbR, also
known as YncC) is the protein product of a highly induced gene in
early Escherichia coli biofilm development
and has been regarded as an attractive target for blocking biofilm
formation. This protein acts as a repressor for genes involved in
exopolysaccharide production and an activator for genes involved in
stress response. To better understand the role of McbR in governing
the switch from exponential growth to the biofilm state, we determined
the crystal structure of McbR to 2.1 Å. The structure reveals
McbR to be a member of the FadR C-terminal domain (FCD) family of
the GntR superfamily of transcriptional regulators (this family was
named after the first identified member, GntR, a transcriptional repressor
of the gluconate operon of Bacillus subtilis). Previous to this study, only six of the predicted 2800 members
of this family had been structurally characterized. Here, we identify
the residues that constitute the McbR effector and DNA binding sites.
In addition, comparison of McbR with other members of the FCD domain
family shows that this family of proteins adopts highly distinct oligomerization
interfaces, which has implications for DNA binding and regulation.
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Affiliation(s)
- Dana M Lord
- Department of Molecular Biology, Cell Biology and Biochemistry, ‡Graduate Program in Molecular Pharmacology and Physiology, and §Department of Molecular Pharmacology, Physiology and Biotechnology & Chemistry, Brown University , Providence, Rhode Island 02903, United States
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Yamamoto K, Watanabe H, Ishihama A. Expression levels of transcription factors in Escherichia coli: growth phase- and growth condition-dependent variation of 90 regulators from six families. Microbiology (Reading) 2014; 160:1903-1913. [DOI: 10.1099/mic.0.079889-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The expression pattern of the genome in Escherichia coli is controlled by regulating the utilization of a limited number of RNA polymerases between a total of 4600 genes on its genome. The distribution pattern of RNA polymerase on the genome changes after two steps of protein–protein interaction with seven sigma subunits and about 300 transcription factors (TFs). Based on a systematic search for the regulation target promoters recognized by each TF, we propose two novel concepts: each TF regulates a number of target promoters; and each promoter is regulated by many TFs. In parallel, attempts have been made to determine the intracellular concentrations of all TFs using two systems: quantitative immunoblot analysis using TF-specific antibodies; and reporter assay of TF promoter activities. The direct measurement of TF protein level has so far been published for a set of 60 regulators with known functions. This study describes the determination of growth phase-dependent expression levels of 90 TFs using the reporter assay system. The translational fusion vector was constructed from the TF promoter sequence including an N-terminal proximal TF segment and the reporter GFP. At the beginning of cell growth, high-level expression was observed only for a small number of TFs. In the exponential phase, approximately 80 % TFs are expressed, but the expressed TF species change upon transfer to the stationary phase. Significant changes in the pattern of TF expression were observed between aerobic and anaerobic conditions. The list of intracellular levels of TFs provides further understanding to the transcription regulation of the E. coli genome under various stressful conditions.
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Affiliation(s)
- Kaneyoshi Yamamoto
- Research Institute of Micro-Nano Technology, Hosei University, Koganei, Tokyo 185-8584, Japan
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 185-8584, Japan
| | - Hiroki Watanabe
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 185-8584, Japan
| | - Akira Ishihama
- Research Institute of Micro-Nano Technology, Hosei University, Koganei, Tokyo 185-8584, Japan
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 185-8584, Japan
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Structural and functional characterization of DUF1471 domains of Salmonella proteins SrfN, YdgH/SssB, and YahO. PLoS One 2014; 9:e101787. [PMID: 25010333 PMCID: PMC4092069 DOI: 10.1371/journal.pone.0101787] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 04/07/2014] [Indexed: 11/20/2022] Open
Abstract
Bacterial species in the Enterobacteriaceae typically contain multiple paralogues of a small domain of unknown function (DUF1471) from a family of conserved proteins also known as YhcN or BhsA/McbA. Proteins containing DUF1471 may have a single or three copies of this domain. Representatives of this family have been demonstrated to play roles in several cellular processes including stress response, biofilm formation, and pathogenesis. We have conducted NMR and X-ray crystallographic studies of four DUF1471 domains from Salmonella representing three different paralogous DUF1471 subfamilies: SrfN, YahO, and SssB/YdgH (two of its three DUF1471 domains: the N-terminal domain I (residues 21–91), and the C-terminal domain III (residues 244–314)). Notably, SrfN has been shown to have a role in intracellular infection by Salmonella Typhimurium. These domains share less than 35% pairwise sequence identity. Structures of all four domains show a mixed α+β fold that is most similar to that of bacterial lipoprotein RcsF. However, all four DUF1471 sequences lack the redox sensitive cysteine residues essential for RcsF activity in a phospho-relay pathway, suggesting that DUF1471 domains perform a different function(s). SrfN forms a dimer in contrast to YahO and SssB domains I and III, which are monomers in solution. A putative binding site for oxyanions such as phosphate and sulfate was identified in SrfN, and an interaction between the SrfN dimer and sulfated polysaccharides was demonstrated, suggesting a direct role for this DUF1471 domain at the host-pathogen interface.
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Landstorfer R, Simon S, Schober S, Keim D, Scherer S, Neuhaus K. Comparison of strand-specific transcriptomes of enterohemorrhagic Escherichia coli O157:H7 EDL933 (EHEC) under eleven different environmental conditions including radish sprouts and cattle feces. BMC Genomics 2014; 15:353. [PMID: 24885796 PMCID: PMC4048457 DOI: 10.1186/1471-2164-15-353] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 03/31/2014] [Indexed: 12/26/2022] Open
Abstract
Background Multiple infection sources for enterohemorrhagic Escherichia coli O157:H7 (EHEC) are known, including animal products, fruit and vegetables. The ecology of this pathogen outside its human host is largely unknown and one third of its annotated genes are still hypothetical. To identify genetic determinants expressed under a variety of environmental factors, we applied strand-specific RNA-sequencing, comparing the SOLiD and Illumina systems. Results Transcriptomes of EHEC were sequenced under 11 different biotic and abiotic conditions: LB medium at pH4, pH7, pH9, or at 15°C; LB with nitrite or trimethoprim-sulfamethoxazole; LB-agar surface, M9 minimal medium, spinach leaf juice, surface of living radish sprouts, and cattle feces. Of 5379 annotated genes in strain EDL933 (genome and plasmid), a surprising minority of only 144 had null sequencing reads under all conditions. We therefore developed a statistical method to distinguish weakly transcribed genes from background transcription. We find that 96% of all genes and 91.5% of the hypothetical genes exhibit a significant transcriptional signal under at least one condition. Comparing SOLiD and Illumina systems, we find a high correlation between both approaches for fold-changes of the induced or repressed genes. The pathogenicity island LEE showed highest transcriptional activity in LB medium, minimal medium, and after treatment with antibiotics. Unique sets of genes, including many hypothetical genes, are highly up-regulated on radish sprouts, cattle feces, or in the presence of antibiotics. Furthermore, we observed induction of the shiga-toxin carrying phages by antibiotics and confirmed active biofilm related genes on radish sprouts, in cattle feces, and on agar plates. Conclusions Since only a minority of genes (2.7%) were not active under any condition tested (null reads), we suggest that the assumption of significant genome over-annotations is wrong. Environmental transcriptomics uncovered hitherto unknown gene functions and unique regulatory patterns in EHEC. For instance, the environmental function of azoR had been elusive, but this gene is highly active on radish sprouts. Thus, NGS-transcriptomics is an appropriate technique to propose new roles of hypothetical genes and to guide future research. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-353) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Klaus Neuhaus
- Lehrstuhl für Mikrobielle Ökologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, D-85350 Freising, Germany.
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Ishchukov I, Wu Y, Van Puyvelde S, Vanderleyden J, Marchal K. Inferring the relation between transcriptional and posttranscriptional regulation from expression compendia. BMC Microbiol 2014; 14:14. [PMID: 24467879 PMCID: PMC3948049 DOI: 10.1186/1471-2180-14-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 01/09/2014] [Indexed: 12/21/2022] Open
Abstract
Background Publicly available expression compendia that measure both mRNAs and sRNAs provide a promising resource to simultaneously infer the transcriptional and the posttranscriptional network. To maximally exploit the information contained in such compendia, we propose an analysis flow that combines publicly available expression compendia and sequence-based predictions to infer novel sRNA-target interactions and to reconstruct the relation between the sRNA and the transcriptional network. Results We relied on module inference to construct modules of coexpressed genes (sRNAs). TFs and sRNAs were assigned to these modules using the state-of-the-art inference techniques LeMoNe and Context Likelihood of Relatedness (CLR). Combining these expressions with sequence-based sRNA-target interactions allowed us to predict 30 novel sRNA-target interactions comprising 14 sRNAs. Our results highlight the role of the posttranscriptional network in finetuning the transcriptional regulation, e.g. by intra-operonic regulation. Conclusion In this work we show how strategies that combine expression information with sequence-based predictions can help unveiling the intricate interaction between the transcriptional and the posttranscriptional network in prokaryotic model systems.
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Affiliation(s)
| | | | | | | | - Kathleen Marchal
- Center of Microbial and Plant Genetics, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
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Hou Z, Fink RC, Sugawara M, Diez-Gonzalez F, Sadowsky MJ. Transcriptional and functional responses of Escherichia coli O157:H7 growing in the lettuce rhizoplane. Food Microbiol 2013; 35:136-42. [PMID: 23664265 DOI: 10.1016/j.fm.2013.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 03/05/2013] [Accepted: 03/06/2013] [Indexed: 11/17/2022]
Abstract
Lettuce and spinach are increasingly implicated in foodborne illness outbreaks due to contamination by Escherichia coli O157:H7. While this bacterium has been shown to colonize and survive on lettuce leaf surfaces, little is known about its interaction with the roots of growing lettuce plants. In these studies, a microarray analyses, mutant construction and confocal microscopy were used to gain an understanding of structure and function of bacterial genes involved in the colonization and growth of E. coli O157:H7 on lettuce roots. After three days of interaction with lettuce roots, 94 and 109 E. coli O157:H7 genes were significantly up- and down-regulated at least 1.5 fold, respectively. While genes involved in biofilm modulation (ycfR and ybiM) were significantly up-regulated, 40 of 109 (37%) of genes involved in protein synthesis were significantly repressed. E. coli O157:H7 was 2 logs less efficient in lettuce root colonization than was E. coli K12. We also unambiguously showed that a ΔycfR mutant of E. coli O157:H7 was unable to attach to or colonize lettuce roots. Taken together these results indicate that bacterial genes involved in attachment and biofilm formation are likely important for contamination of lettuce plants with Shiga toxin-producing E. coli strains.
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Affiliation(s)
- Zhe Hou
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108, USA
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GlgS, described previously as a glycogen synthesis control protein, negatively regulates motility and biofilm formation in Escherichia coli. Biochem J 2013; 452:559-73. [PMID: 23537328 DOI: 10.1042/bj20130154] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Escherichia coli glycogen metabolism involves the regulation of glgBXCAP operon expression and allosteric control of the GlgC [ADPG (ADP-glucose) pyrophosphorylase]-mediated catalysis of ATP and G1P (glucose-1-phosphate) to ADPG linked to glycogen biosynthesis. E. coli glycogen metabolism is also affected by glgS. Though the precise function of the protein it encodes is unknown, its deficiency causes both reduced glycogen content and enhanced levels of the GlgC-negative allosteric regulator AMP. The transcriptomic analyses carried out in the present study revealed that, compared with their isogenic BW25113 wild-type strain, glgS-null (ΔglgS) mutants have increased expression of the operons involved in the synthesis of type 1 fimbriae adhesins, flagella and nucleotides. In agreement, ΔglgS cells were hyperflagellated and hyperfimbriated, and displayed elevated swarming motility; these phenotypes all reverted to the wild-type by ectopic glgS expression. Also, ΔglgS cells accumulated high colanic acid content and displayed increased ability to form biofilms on polystyrene surfaces. F-driven conjugation based on large-scale interaction studies of glgS with all the non-essential genes of E. coli showed that deletion of purine biosynthesis genes complement the glycogen-deficient, high motility and high biofilm content phenotypes of ΔglgS cells. Overall the results of the present study indicate that glycogen deficiency in ΔglgS cells can be ascribed to high flagellar propulsion and high exopolysaccharide and purine nucleotides biosynthetic activities competing with GlgC for the same ATP and G1P pools. Supporting this proposal, glycogen-less ΔglgC cells displayed an elevated swarming motility, and accumulated high levels of colanic acid and biofilm. Furthermore, glgC overexpression reverted the glycogen-deficient, high swarming motility, high colanic acid and high biofilm content phenotypes of ΔglgS cells to the wild-type. As on the basis of the present study GlgS has emerged as a major determinant of E. coli surface composition and because its effect on glycogen metabolism appears to be only indirect, we propose to rename it as ScoR (surface composition regulator).
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Joshi N, Ngwenya BT, French CE. Enhanced resistance to nanoparticle toxicity is conferred by overproduction of extracellular polymeric substances. JOURNAL OF HAZARDOUS MATERIALS 2012; 241-242:363-70. [PMID: 23098996 DOI: 10.1016/j.jhazmat.2012.09.057] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 09/19/2012] [Accepted: 09/22/2012] [Indexed: 05/10/2023]
Abstract
The increasing production and use of engineered nanoparticles, coupled with their demonstrated toxicity to different organisms, demands the development of a systematic understanding of how nanoparticle toxicity depends on important environmental parameters as well as surface properties of both cells and nanomaterials. We demonstrate that production of the extracellular polymeric substance (EPS), colanic acid by engineered Escherichia coli protects the bacteria against silver nanoparticle toxicity. Moreover, exogenous addition of EPS to a control strain results in an increase in cell viability, as does the addition of commercial EPS polymer analogue xanthan. Furthermore, we have found that an EPS producing strain of Sinorhizobium meliloti shows higher survival upon exposure to silver nanoparticles than the parent strain. Transmission electron microscopy (TEM) observations showed that EPS traps the nanoparticles outside the cells and reduces the exposed surface area of cells to incoming nanoparticles by inducing cell aggregation. Nanoparticle size characterization in the presence of EPS and xanthan indicated a marked tendency towards aggregation. Both are likely effective mechanisms for reducing nanoparticle toxicity in the natural environment.
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Affiliation(s)
- Nimisha Joshi
- School of GeoSciences, Microbial Geochemistry Laboratory, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, United Kingdom.
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Hou Z, Fink RC, Black EP, Sugawara M, Zhang Z, Diez-Gonzalez F, Sadowsky MJ. Gene expression profiling of Escherichia coli in response to interactions with the lettuce rhizosphere. J Appl Microbiol 2012; 113:1076-86. [PMID: 22830299 DOI: 10.1111/j.1365-2672.2012.05412.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/09/2012] [Accepted: 07/21/2012] [Indexed: 11/29/2022]
Abstract
AIMS The objective of this study was to examine transcriptional changes in Escherichia coli when the bacterium was growing in the lettuce rhizoshpere. METHODS AND RESULTS A combination of microarray analyses, colonization assays and confocal microscopy was used to gain a more complete understanding of bacterial genes involved in the colonization and growth of E. coli K12 in the lettuce root rhizosphere using a novel hydroponic assay system. After 3 days of interaction with lettuce roots, E. coli genes involved in protein synthesis, stress responses and attachment were up-regulated. Mutants in curli production (crl, csgA) and flagella synthesis (fliN) had a reduced capacity to attach to roots as determined by bacterial counts and by confocal laser scanning microscopy. CONCLUSIONS This study indicates that E. coli K12 has the capability to colonize lettuce roots by using attachment genes and can readily adapt to the rhizosphere of lettuce plants. SIGNIFICANCE AND IMPACT OF THE STUDY Results of this study show curli production and biofilm modulation genes are important for rhizosphere colonization and may provide useful targets to disrupt this process. Further studies using pathogenic strains will provide additional information about lettuce-E. coli interactions.
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Affiliation(s)
- Z Hou
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
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Norton JP, Mulvey MA. Toxin-antitoxin systems are important for niche-specific colonization and stress resistance of uropathogenic Escherichia coli. PLoS Pathog 2012; 8:e1002954. [PMID: 23055930 PMCID: PMC3464220 DOI: 10.1371/journal.ppat.1002954] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 08/16/2012] [Indexed: 01/04/2023] Open
Abstract
Toxin-antitoxin (TA) systems are prevalent in many bacterial genomes and have been implicated in biofilm and persister cell formation, but the contribution of individual chromosomally encoded TA systems during bacterial pathogenesis is not well understood. Of the known TA systems encoded by Escherichia coli, only a subset is associated with strains of extraintestinal pathogenic E. coli (ExPEC). These pathogens colonize diverse niches and are a major cause of sepsis, meningitis, and urinary tract infections. Using a murine infection model, we show that two TA systems (YefM-YoeB and YbaJ-Hha) independently promote colonization of the bladder by the reference uropathogenic ExPEC isolate CFT073, while a third TA system comprised of the toxin PasT and the antitoxin PasI is critical to ExPEC survival within the kidneys. The PasTI TA system also enhances ExPEC persister cell formation in the presence of antibiotics and markedly increases pathogen resistance to nutrient limitation as well as oxidative and nitrosative stresses. On its own, low-level expression of PasT protects ExPEC from these stresses, whereas overexpression of PasT is toxic and causes bacterial stasis. PasT-induced stasis can be rescued by overexpression of PasI, indicating that PasTI is a bona fide TA system. By mutagenesis, we find that the stress resistance and toxic effects of PasT can be uncoupled and mapped to distinct domains. Toxicity was specifically linked to sequences within the N-terminus of PasT, a region that also promotes the development of persister cells. These results indicate discrete, multipurpose functions for a TA-associated toxin and demonstrate that individual TA systems can provide bacteria with pronounced fitness advantages dependent on toxin expression levels and the specific environmental niche occupied. Toxin-antitoxin (TA) systems are widespread among prokaryotes, including many important human pathogens. It has long been hypothesized that TA systems contribute to bacterial pathogenesis, but clear-cut phenotypes associated with any individual TA system have not been described. Using bioinformatics, we demonstrate that distinct subsets of TA systems are linked with a major group of bacterial pathogens known as Extraintestinal Pathogenic E. coli (ExPEC). These bacteria are responsible for the majority of urinary tract infections worldwide, and are major causes of sepsis and meningitis. Using murine infection models with a reference uropathogenic ExPEC isolate, we found that three of the ExPEC-associated TA systems act independently to promote bacterial survival and persistence within the host urinary tract. Furthermore, we show that the toxin protein associated with one of these TA systems increases ExPEC stress resistance and persistence in the face of antibiotics. This work demonstrates the functional importance of specific TA systems to ExPEC pathogenesis, highlighting their potential as therapeutic targets.
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Affiliation(s)
| | - Matthew A. Mulvey
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail:
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Sheng L, Pu M, Hegde M, Zhang Y, Jayaraman A, Wood TK. Interkingdom adenosine signal reduces Pseudomonas aeruginosa pathogenicity. Microb Biotechnol 2012; 5:560-72. [PMID: 22414222 PMCID: PMC3815332 DOI: 10.1111/j.1751-7915.2012.00338.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Pseudomonas aeruginosa is becoming recognized as an important pathogen in the gastrointestinal (GI) tract. Here we demonstrate that adenosine, derived from hydrolysis of ATP from the eucaryotic host, is a potent interkingdom signal in the GI tract for this pathogen. The addition of adenosine nearly abolished P. aeruginosa biofilm formation and abolished swarming by preventing production of rhamnolipids. Since the adenosine metabolite inosine did not affect biofilm formation and since a mutant unable to metabolize adenosine behaved like the wild-type strain, adenosine metabolism is not required to reduce pathogenicity. Adenosine also reduces production of the virulence factors pyocyanin, elastase, extracellular polysaccharide, siderophores and the Pseudomonas quinolone signal which led to reduced virulence with Caenorhabditis elegans. To provide insights into how adenosine reduces the virulence of P. aeruginosa, a whole-transcriptome analysis was conducted which revealed that adenosine addition represses genes similar to an iron-replete condition; however, adenosine did not directly bind Fur. Therefore, adenosine decreases P. aeruginosa pathogenicity as an interkingdom signal by causing genes related to iron acquisition to be repressed.
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Affiliation(s)
- Lili Sheng
- Department of Chemical Engineering, Texas A & M University, College Station, TX 77843-3122, USA
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Shrout JD, Nerenberg R. Monitoring bacterial twitter: does quorum sensing determine the behavior of water and wastewater treatment biofilms? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:1995-2005. [PMID: 22296043 DOI: 10.1021/es203933h] [Citation(s) in RCA: 176] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Bacteria have their own form of "twitter" communication, described as quorum sensing (QS), where bacteria emit and sense chemical signal molecules as a means to gauge population density and control gene expression. Many QS-controlled genes relate to biofilm formation and function and may be important for some water and wastewater treatment biofilms. There is a need to better understand bacterial QS, the bacteria biofilm aspects influenced by QS in engineered reactors, and to assess how designs and operations might be improved by taking this signaling into account. This paper provides a critical review of QS and how it relates to biofilms in engineered water and wastewater treatment systems and identifies needs for future research.
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Affiliation(s)
- Joshua D Shrout
- Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, Indiana, United States.
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Hong SH, Wang X, O'Connor HF, Benedik MJ, Wood TK. Bacterial persistence increases as environmental fitness decreases. Microb Biotechnol 2012; 5:509-22. [PMID: 22221537 PMCID: PMC3323757 DOI: 10.1111/j.1751-7915.2011.00327.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Since persister cells cause chronic infections and since Escherichia coli toxin MqsR increases persisters, we used protein engineering to increase the toxicity of MqsR to gain insights into persister cell formation. Through two amino acid replacements that increased the stability of MqsR, toxicity and persistence were increased. A whole‐transcriptome study revealed that the MqsR variant increased persistence by repressing genes for acid resistance, multidrug resistance and osmotic resistance. Corroborating these microarray results, deletion of rpoS, as well as the genes that the master stress response regulator RpoS controls, increased persister formation dramatically to the extent that nearly the whole population became persistent. Furthermore, wild‐type cells stressed by prior treatment to acid or hydrogen peroxide increased persistence 12 000‐fold. Whole‐transcriptome analyses of persister cells generated by two different methods (wild‐type cells pretreated with hydrogen peroxide and the rpoS deletion) corroborated the importance of suppressing RpoS in persister cell formation. Therefore, the more toxic MqsR increases persistence by decreasing the ability of the cell to respond to antibiotic stress through its RpoS‐based regulation of acid resistance, multidrug resistance and osmotic resistance systems.
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Affiliation(s)
- Seok Hoon Hong
- Departments of Chemical Engineering Biology, Texas A&M University, College Station, TX 77843-3122, USA
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Abstract
In their stressful natural environments, bacteria often are in stationary phase and use their limited resources for maintenance and stress survival. Underlying this activity is the general stress response, which in Escherichia coli depends on the σS (RpoS) subunit of RNA polymerase. σS is closely related to the vegetative sigma factor σ70 (RpoD), and these two sigmas recognize similar but not identical promoter sequences. During the postexponential phase and entry into stationary phase, σS is induced by a fine-tuned combination of transcriptional, translational, and proteolytic control. In addition, regulatory "short-cuts" to high cellular σS levels, which mainly rely on the rapid inhibition of σS proteolysis, are triggered by sudden starvation for various nutrients and other stressful shift conditons. σS directly or indirectly activates more than 500 genes. Additional signal input is integrated by σS cooperating with various transcription factors in complex cascades and feedforward loops. Target gene products have stress-protective functions, redirect metabolism, affect cell envelope and cell shape, are involved in biofilm formation or pathogenesis, or can increased stationary phase and stress-induced mutagenesis. This review summarizes these diverse functions and the amazingly complex regulation of σS. At the molecular level, these processes are integrated with the partitioning of global transcription space by sigma factor competition for RNA polymerase core enzyme and signaling by nucleotide second messengers that include cAMP, (p)ppGpp, and c-di-GMP. Physiologically, σS is the key player in choosing between a lifestyle associated with postexponential growth based on nutrient scavenging and motility and a lifestyle focused on maintenance, strong stress resistance, and increased adhesiveness. Finally, research with other proteobacteria is beginning to reveal how evolution has further adapted function and regulation of σS to specific environmental niches.
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Ma Q, Zhang G, Wood TK. Escherichia coli BdcA controls biofilm dispersal in Pseudomonas aeruginosa and Rhizobium meliloti. BMC Res Notes 2011; 4:447. [PMID: 22029875 PMCID: PMC3214192 DOI: 10.1186/1756-0500-4-447] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 10/26/2011] [Indexed: 11/10/2022] Open
Abstract
Background Previously we showed that BdcA controls Escherichia coli biofilm dispersal by binding the ubiquitous bacterial signal cyclic diguanylate (c-di-GMP); upon reducing the concentration of c-di-GMP, the cell shifts to the planktonic state by increasing motility, decreasing aggregation, and decreasing production of biofilm adhesins. Findings Here we report that BdcA also increases biofilm dispersal in other Gram-negative bacteria including Pseudomonas aeruginosa, Pseudomonas fluorescens, and Rhizobium meliloti. BdcA binds c-di-GMP in these strains and thereby reduces the effective c-di-GMP concentrations as demonstrated by increases in swimming motility and swarming motility as well as by a reduction in extracellular polysaccharide production. We also develop a method to displace existing biofilms by adding BdcA via conjugation from E. coli in mixed-species biofilms. Conclusion Since BdcA shows the ability to control biofilm dispersal in diverse bacteria, BdcA has the potential to be used as a tool to disperse biofilms for engineering and medical applications.
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Affiliation(s)
- Qun Ma
- Department of Chemical Engineering, Texas A & M University, College Station, TX 77843-3122, USA.
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May T, Okabe S. Enterobactin is required for biofilm development in reduced-genome Escherichia coli. Environ Microbiol 2011; 13:3149-62. [DOI: 10.1111/j.1462-2920.2011.02607.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Bacteria prefer to grow attached to themselves or an interface, and it is important for an array of applications to make biofilms disperse. Here we report simultaneously the discovery and protein engineering of BdcA (formerly YjgI) for biofilm dispersal using the universal signal 3,5-cyclic diguanylic acid (c-di-GMP). The bdcA deletion reduced biofilm dispersal, and production of BdcA increased biofilm dispersal to wild-type level. Since BdcA increases motility and extracellular DNA production while decreasing exopolysaccharide, cell length and aggregation, we reasoned that BdcA decreases the concentration of c-di-GMP, the intracellular messenger that controls cell motility through flagellar rotation and biofilm formation through synthesis of curli and cellulose. Consistently, c-di-GMP levels increase upon deleting bdcA, and purified BdcA binds c-di-GMP but does not act as a phosphodiesterase. Additionally, BdcR (formerly YjgJ) is a negative regulator of bdcA. To increase biofilm dispersal, we used protein engineering to evolve BdcA for greater c-di-GMP binding and found that the single amino acid change E50Q causes nearly complete removal of biofilms via dispersal without affecting initial biofilm formation.
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Affiliation(s)
- Qun Ma
- Department of Chemical Engineering, 220 Jack E. Brown Building, Texas A & M University, College Station, TX 77843-3122
| | - Zhonghua Yang
- Department of Chemical Engineering, 220 Jack E. Brown Building, Texas A & M University, College Station, TX 77843-3122
- College of Chemical Engineering and Technology, Wuhan University of Science and Technology, Wuhan 430081
| | - Mingming Pu
- Department of Chemical Engineering, 220 Jack E. Brown Building, Texas A & M University, College Station, TX 77843-3122
| | - Wolfgang Peti
- Department of Molecular Pharmacology, Physiology, and Biotechnology and Brown University, Providence, RI 02912
| | - Thomas K. Wood
- Department of Chemical Engineering, 220 Jack E. Brown Building, Texas A & M University, College Station, TX 77843-3122
- Department of Biology, 220 Jack E. Brown Building, Texas A & M University, College Station, TX 77843-3122
- Department of Civil Engineering, 220 Jack E. Brown Building, Texas A & M University, College Station, TX 77843-3122
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Thao S, Chen CS, Zhu H, Escalante-Semerena JC. Nε-lysine acetylation of a bacterial transcription factor inhibits Its DNA-binding activity. PLoS One 2010; 5:e15123. [PMID: 21217812 PMCID: PMC3013089 DOI: 10.1371/journal.pone.0015123] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 10/21/2010] [Indexed: 01/04/2023] Open
Abstract
Evidence suggesting that eukaryotes and archaea use reversible N(ε)-lysine (N(ε)-Lys) acetylation to modulate gene expression has been reported, but evidence for bacterial use of N(ε)-Lys acetylation for this purpose is lacking. Here, we report data in support of the notion that bacteria can control gene expression by modulating the acetylation state of transcription factors (TFs). We screened the E. coli proteome for substrates of the bacterial Gcn5-like protein acetyltransferase (Pat). Pat acetylated four TFs, including the RcsB global regulatory protein, which controls cell division, and capsule and flagellum biosynthesis in many bacteria. Pat acetylated residue Lys180 of RcsB, and the NAD(+)-dependent Sir2 (sirtuin)-like protein deacetylase (CobB) deacetylated acetylated RcsB (RcsB(Ac)), demonstrating that N(ε)-Lys acetylation of RcsB is reversible. Analysis of RcsB(Ac) and variant RcsB proteins carrying substitutions at Lys180 provided biochemical and physiological evidence implicating Lys180 as a critical residue for RcsB DNA-binding activity. These findings further the likelihood that reversible N(ε)-Lys acetylation of transcription factors is a mode of regulation of gene expression used by all cells.
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Affiliation(s)
- Sandy Thao
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Chien-Sheng Chen
- Department of Pharmacology and Molecular Sciences and High-Throughput Biology Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jhongli, Taiwan
| | - Heng Zhu
- Department of Pharmacology and Molecular Sciences and High-Throughput Biology Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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