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Klubthawee N, Wongchai M, Aunpad R. The bactericidal and antibiofilm effects of a lysine-substituted hybrid peptide, CM-10K14K, on biofilm-forming Staphylococcus epidermidis. Sci Rep 2023; 13:22262. [PMID: 38097636 PMCID: PMC10721899 DOI: 10.1038/s41598-023-49302-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023] Open
Abstract
Staphylococci, notably biofilm-forming Staphylococcus epidermidis, have been recognized as global nosocomial pathogens in medical device-related infections. Their potential to attach to and form biofilm on indwelling catheters are significant factors impeding conventional treatment. Due to their extensive antimicrobial and antibiofilm actions, antimicrobial peptides (AMPs) have attracted interest as promising alternative compounds for curing difficult-to-treat, biofilm-forming bacterial infections. Cecropin A-melittin or CM, a well-known hybrid peptide, exhibits broad-spectrum antimicrobial activity, however it also possesses high toxicity. In the current study, a series of hybrid CM derivatives was designed using an amino acid substitution strategy to explore potential antibacterial and antibiofilm peptides with low toxicity. Among the derivatives, CM-10K14K showed the least hemolysis along with potent antibacterial activity against biofilm-forming S. epidermidis (MICs = 3.91 μg/mL) and rapid killing after 15 min exposure (MBCs = 7.81 μg/mL). It can prevent the formation of S. epidermidis biofilm and also exhibited a dose-dependent eradication activity on mature or established S. epidermidis biofilm. In addition, it decreased the development of biofilm by surviving bacteria, and formation of biofilm on the surface of CM-10K14K-impregnated catheters. Released CM-10K14K decreased planktonic bacterial growth and inhibited biofilm formation by S. epidermidis in a dose-dependent manner for 6 and 24 h post-exposure. Impregnation of CM-10K14K prevented bacterial attachment on catheters and thus decreased formation of extensive biofilms. SEM images supported the antibiofilm activity of CM-10K14K. Flow cytometry analysis and TEM images demonstrated a membrane-active mechanism of CM-10K14K, inducing depolarization and permeabilization, and subsequent membrane rupture leading to cell death. The presence of an interaction with bacterial DNA was verified by gel retardation assay. These antibacterial and antibiofilm activities of CM-10K14K suggest its potential application to urinary catheters for prevention of biofilm-forming colonization or for treatment of medical devices infected with S. epidermidis.
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Affiliation(s)
- Natthaporn Klubthawee
- Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Khlong Luang, 12120, Pathum Thani, Thailand
| | - Mathira Wongchai
- Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Khlong Luang, 12120, Pathum Thani, Thailand
| | - Ratchaneewan Aunpad
- Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Khlong Luang, 12120, Pathum Thani, Thailand.
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Veigyabati Devi M, Singh AK. Delineation of transcriptional regulators involve in biofilm formation cycle of Mycobacterium abscessus. Gene 2023; 882:147644. [PMID: 37479094 DOI: 10.1016/j.gene.2023.147644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/01/2023] [Accepted: 07/12/2023] [Indexed: 07/23/2023]
Abstract
Mycobacterium abscessus is an intrinsically and acquired multidrug resistant (MDR) intracellular pathogen with biofilm formation capability and limited option for treatment. Biofilm is the major characteristic that leads to failure and prolong treatment, intensifies treatment cost and increases mortality/morbidity rate. However, the biofilm formation regulations of M. abscessus remain largely unexplored. In this study, we identify the putative/hypothetical transcriptional regulator (TR) of M. abscessus that are involved in biofilm formation. This study includes fifty TRs belonging to thirteen different families viz., AraC, ArsR, AsnC, CarD, CdaR, GntR, IclR, LysR, MarR, PadR, PrrA, TetR and WhiB, including TRs of unknown family. The promoter of these putative TRs were fused individually with GFP and analyzed their expression using CLSM in planktonic phase and early, mid and mature stages of biofilm formation phase, which overall termed as biofilm formation cycle. Further, qRT-PCR was carried out for selected TRs to analyze their differential expressions. This study found thirteen numbers of TR belonging to TetR family, five TRs belonging to MarR family, four TRs of unannotated TR family, two AraC TRs, two LysR, two GntR, two AsnC, one each of ArsR family, CarD family, IclR family, PadR family, PrrA family and WhiB family selected for this study are involved in biofilm formation cycle. Our study characterized the TRs with respect to their role in biofilm formation for the first time in M. abscessus and also found that their biofilm formation is regulated by diverse TR families.
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Affiliation(s)
- Moirangthem Veigyabati Devi
- Biological Sciences and Technology Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Anil Kumar Singh
- Biological Sciences and Technology Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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Alves JA, Previato-Mello M, Barroso KCM, Koide T, da Silva Neto JF. The MarR family regulator OsbR controls oxidative stress response, anaerobic nitrate respiration, and biofilm formation in Chromobacterium violaceum. BMC Microbiol 2021; 21:304. [PMID: 34736409 PMCID: PMC8567585 DOI: 10.1186/s12866-021-02369-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 10/26/2021] [Indexed: 12/16/2022] Open
Abstract
Background Chromobacterium violaceum is an environmental opportunistic pathogen that causes rare but deadly infections in humans. The transcriptional regulators that C. violaceum uses to sense and respond to environmental cues remain largely unknown. Results Here, we described a novel transcriptional regulator in C. violaceum belonging to the MarR family that we named OsbR (oxidative stress response and biofilm formation regulator). Transcriptome profiling by DNA microarray using strains with deletion or overexpression of osbR showed that OsbR exerts a global regulatory role in C. violaceum, regulating genes involved in oxidative stress response, nitrate reduction, biofilm formation, and several metabolic pathways. EMSA assays showed that OsbR binds to the promoter regions of several OsbR-regulated genes, and the in vitro DNA binding activity was inhibited by oxidants. We demonstrated that the overexpression of osbR caused activation of ohrA even in the presence of the repressor OhrR, which resulted in improved growth under organic hydroperoxide treatment, as seem by growth curve assays. We showed that the proper regulation of the nar genes by OsbR ensures optimal growth of C. violaceum under anaerobic conditions by tuning the reduction of nitrate to nitrite. Finally, the osbR overexpressing strain showed a reduction in biofilm formation, and this phenotype correlated with the OsbR-mediated repression of two gene clusters encoding putative adhesins. Conclusions Together, our data indicated that OsbR is a MarR-type regulator that controls the expression of a large number of genes in C. violaceum, thereby contributing to oxidative stress defense (ohrA/ohrR), anaerobic respiration (narK1K2 and narGHJI), and biofilm formation (putative RTX adhesins). Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02369-x.
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Affiliation(s)
- Júlia A Alves
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Maristela Previato-Mello
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Kelly C M Barroso
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Tie Koide
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - José F da Silva Neto
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
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Speers AM, Reguera G. Competitive advantage of oxygen-tolerant bioanodes of Geobacter sulfurreducens in bioelectrochemical systems. Biofilm 2021; 3:100052. [PMID: 34222855 PMCID: PMC8242959 DOI: 10.1016/j.bioflm.2021.100052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 10/31/2022] Open
Abstract
Oxidative stress greatly limits current harvesting from anode biofilms in bioelectrochemical systems yet insufficient knowledge of the antioxidant responses of electricigens prevents optimization. Using Geobacter sulfurreducens PCA as a model electricigen, we demonstrated enhanced oxygen tolerance and reduced electron losses as the biofilms grew in height on the anode. To investigate the molecular basis of biofilm tolerance, we developed a genetic screening and isolated 11 oxygen-tolerant (oxt) strains from a library of transposon-insertion mutants. The aggregative properties of the oxt mutants promoted biofilm formation and oxygen tolerance. Yet, unlike the wild type, none of the mutants diverted respiratory electrons to oxygen. Most of the oxt mutations inactivated pathways for the detoxification of reactive oxygen species that could have triggered compensatory chronic responses to oxidative stress and inhibit aerobic respiration. One of the mutants (oxt10) also had a growth advantage with Fe(III) oxides and during the colonization of the anode electrode. The enhanced antioxidant response in this mutant reduced the system's start-up and promoted current harvesting from bioanodes even in the presence of oxygen. These results highlight a hitherto unknown role of oxidative stress responses in the stability and performance of current-harvesting biofilms of G. sulfurreducens and identify biological and engineering approaches to grow electroactive biofilms with the resilience needed for practical applications.
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Affiliation(s)
- Allison M Speers
- Department of Microbiology and Molecular Genetics, Michigan State University, USA
| | - Gemma Reguera
- Department of Microbiology and Molecular Genetics, Michigan State University, USA
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Hajian Z, Ghasemi MF, Alikhani FE. The study of stress conditions on growth and proteome of Raoultella planticola: a new emerging pathogen. Arch Microbiol 2021; 203:3269-78. [PMID: 33846829 DOI: 10.1007/s00203-021-02312-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/26/2021] [Accepted: 03/29/2021] [Indexed: 10/21/2022]
Abstract
All bacteria can survive and adapt to different stresses, such as fluctuations in temperature, pH oxidative, and osmotic pressure occurring in their surrounding environments. This study aims to evaluate the effects of a variety of stress conditions on the growth, and proteome of Raoultella planticola PTCC 1598. R. planticola cells were exposed to different values of temperatures, sodium chloride, pH, and hydrogen peroxide stresses. Among the stress conditions, oxidative stress, upon exposure to hydrogen peroxide (H2O2) at 4000 ppm concentration was selected for proteomics analysis in detail. Approximately, 1400 spots were identified in two-dimensional gel electrophoresis (2-DE). Among the identified spots, 85 spots were repeatable using 2D-Platinum software and eye confirmation and, nine protein spots were differentially expressed. Among nine proteins, six proteins identified successfully with an MASCOT score greater than 40 (p < 0.05) were 2,3-dihydroxybenzoate-2,3-dehydrogenase (oxidoreductase family), hypothetical protein G787-04832, periplasmic D-galactose-binding protein, uridine phosphorylase (glycosyltransferases), a single peptide match to cysteine-binding periplasmic protein, and NADP(H) nitroreductase. All identified proteins showed decreased level expression. Based on the obtained results, we concluded that hydrogen peroxide as an antiseptic compound could affect cell growth and proteomics of R. planticola. Therefore, we recommend using an antiseptic solution containing H2O2 to prevent the spread of R. planticola as a new emerging pathogen.
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Gu L, Liu X, Wang YQ, Zhou YT, Zhu HW, Huang J, Lan LF, Zheng J, Yang CG, Zhou H. Revelation of AbfR in regulation of mismatch repair and energy metabolism in S. epidermidis by integrated proteomic and metabolomic analysis. J Proteomics 2020; 226:103900. [PMID: 32711166 DOI: 10.1016/j.jprot.2020.103900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 12/15/2022]
Abstract
Staphylococcus epidermidis is a common causative of nosocomial infections associated with indwelling medical devices. To date, the mechanisms of the pathogenicity and drug resistance of S. epidermidis have not been clearly elucidated. AbfR has been previously identified as an oxidation-sensing regulator that regulates bacterial aggregation and biofilm formation by responding to oxidative stress in S. epidermidis; however, the regulatory pathways of AbfR are underexplored. In this study, we investigated the oxidation-sensing regulatory mechanism of AbfR using TMT10-plex labelling quantitative proteomic and untargeted metabolomic approaches. Integrated analysis of two omics datasets indicated that abfR depletion influenced nucleic acid metabolism and activated the DNA mismatch repair pathway. In addition, several energy-related metabolic pathways, including tricarboxylic acid (TCA) cycle, glycolysis, and arginine metabolism, were remarkably impacted by the deletion of abfR. This study revealed the regulatory networks of the transcription factor AbfR from a multi-omics view and demonstrated that AbfR played a broad role in not only mismatch repair but also energy metabolism, enabling S. epidermidis to constantly sense and adapt to environmental stress. SIGNIFICANCE: Staphylococcus epidermidis has emerged as a major nosocomial infection causing pathogen. AbfR, a transcription factor of S. epidermidis, plays an important role in oxidative stress, cell aggregation, and biofilm formation; however, the regulatory mechanism of AbfR is unknown. Using proteomic and metabolomic approaches, this study unveils the global regulatory networks of AbfR, and demonstrates that AbfR not only regulates the DNA mismatch repair pathway by an oxidation sensing mechanism but also affects energy metabolism. This study expands the body of knowledge related to regulatory transcription factors in staphylococci and lays a foundation for future research on clinical infections caused by S. epidermidis.
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Affiliation(s)
- Lei Gu
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China; Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xing Liu
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yu-Qiu Wang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Yan-Ting Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Hong-Wen Zhu
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jin Huang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Le-Fu Lan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Number 19A Yuquan Road, Beijing 100049, China
| | - Jing Zheng
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
| | - Cai-Guang Yang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Number 19A Yuquan Road, Beijing 100049, China..
| | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Number 19A Yuquan Road, Beijing 100049, China..
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Young D, Pedre B, Ezeriņa D, De Smet B, Lewandowska A, Tossounian MA, Bodra N, Huang J, Astolfi Rosado L, Van Breusegem F, Messens J. Protein Promiscuity in H 2O 2 Signaling. Antioxid Redox Signal 2019; 30:1285-1324. [PMID: 29635930 DOI: 10.1089/ars.2017.7013] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
SIGNIFICANCE Decrypting the cellular response to oxidative stress relies on a comprehensive understanding of the redox signaling pathways stimulated under oxidizing conditions. Redox signaling events can be divided into upstream sensing of oxidants, midstream redox signaling of protein function, and downstream transcriptional redox regulation. Recent Advances: A more and more accepted theory of hydrogen peroxide (H2O2) signaling is that of a thiol peroxidase redox relay, whereby protein thiols with low reactivity toward H2O2 are instead oxidized through an oxidative relay with thiol peroxidases. CRITICAL ISSUES These ultrareactive thiol peroxidases are the upstream redox sensors, which form the first cellular port of call for H2O2. Not all redox-regulated interactions between thiol peroxidases and cellular proteins involve a transfer of oxidative equivalents, and the nature of redox signaling is further complicated through promiscuous functions of redox-regulated "moonlighting" proteins, of which the precise cellular role under oxidative stress can frequently be obscured by "polygamous" interactions. An ultimate goal of redox signaling is to initiate a rapid response, and in contrast to prokaryotic oxidant-responsive transcription factors, mammalian systems have developed redox signaling pathways, which intersect both with kinase-dependent activation of transcription factors, as well as direct oxidative regulation of transcription factors through peroxiredoxin (Prx) redox relays. FUTURE DIRECTIONS We highlight that both transcriptional regulation and cell fate can be modulated either through oxidative regulation of kinase pathways, or through distinct redox-dependent associations involving either Prxs or redox-responsive moonlighting proteins with functional promiscuity. These protein associations form systems of crossregulatory networks with multiple nodes of potential oxidative regulation for H2O2-mediated signaling.
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Affiliation(s)
- David Young
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Brandan Pedre
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Daria Ezeriņa
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Barbara De Smet
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Aleksandra Lewandowska
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Maria-Armineh Tossounian
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Nandita Bodra
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Jingjing Huang
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Leonardo Astolfi Rosado
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Frank Van Breusegem
- 2 Brussels Center for Redox Biology, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Joris Messens
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
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Ong KS, Mawang CI, Daniel-Jambun D, Lim YY, Lee SM. Current anti-biofilm strategies and potential of antioxidants in biofilm control. Expert Rev Anti Infect Ther 2018; 16:855-864. [PMID: 30308132 DOI: 10.1080/14787210.2018.1535898] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Biofilm formation is a strategy for microorganisms to adapt and survive in hostile environments. Microorganisms that are able to produce biofilms are currently recognized as a threat to human health. Areas covered: Many strategies have been employed to eradicate biofilms, but several drawbacks from these methods had subsequently raised concerns on the need for alternative approaches to effectively prevent biofilm formation. One of the main mechanisms that drives a microorganism to transit from a planktonic to a biofilm-sessile state, is oxidative stress. Chemical agents that could target oxidative stress regulators, for instance antioxidants, could therefore be used to treat biofilm-associated infections. Expert commentary: The focus of this review is to summarize the function and limitation of the current anti-biofilm strategies and will propose the use of antioxidants as an alternative method to treat, prevent and eradicate biofilms. Studies have shown that water-soluble and lipid-soluble antioxidants can reduce and prevent biofilm formation, by influencing the expression of genes associated with oxidative stress. Further in vivo work should be conducted to ensure the efficacy of these antioxidants in a biological environment. Nevertheless, antioxidants are promising anti-biofilm agents, and thus is a potential solution for biofilm-associated infections in the future.
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Affiliation(s)
- Kuan Shion Ong
- a School of Science , Monash University Malaysia , Bandar Sunway , Selangor , Malaysia.,b Tropical Medicine and Biology Multidisciplinary Platform , Monash University Malaysia , Bandar Sunway , Selangor , Malaysia
| | | | | | - Yau Yan Lim
- a School of Science , Monash University Malaysia , Bandar Sunway , Selangor , Malaysia
| | - Sui Mae Lee
- a School of Science , Monash University Malaysia , Bandar Sunway , Selangor , Malaysia.,b Tropical Medicine and Biology Multidisciplinary Platform , Monash University Malaysia , Bandar Sunway , Selangor , Malaysia
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Wang X, Han H, Lv Z, Lin Z, Shang Y, Xu T, Wu Y, Zhang Y, Qu D. PhoU2 but Not PhoU1 as an Important Regulator of Biofilm Formation and Tolerance to Multiple Stresses by Participating in Various Fundamental Metabolic Processes in Staphylococcus epidermidis. J Bacteriol 2017; 199:e00219-17. [PMID: 28947672 DOI: 10.1128/JB.00219-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 08/18/2017] [Indexed: 12/17/2022] Open
Abstract
PhoU, a conserved protein that has been proposed to coordinate phosphate import, is a negative regulator of drug tolerance in most bacteria. In Staphylococcus epidermidis, the role of PhoU in biofilm formation and drug tolerance has not yet been investigated. Two PhoU homologs in the genome of S. epidermidis have been identified by the presence of the conserved motif E(D)XXXD of PhoU. We separately constructed ΔphoU1 and ΔphoU2 mutants of S. epidermidis strain 1457. The ΔphoU2 mutant displayed growth retardation, a weakened biofilm formation capacity, a higher sensitivity to H2O2, and reduced tolerance to multiple antibiotics. However, deletion of phoU1 had no effect on those. We compared the transcriptome profiles of the ΔphoU2 and ΔphoU1 mutants with that of the parent strain. In the ΔphoU2 mutant, expression of genes related to inorganic phosphate uptake was significantly upregulated (pst operon) and the levels of intracellular inorganic polyphosphate (polyP) were increased. In the ΔphoU2 mutant, expression of enzymes in the pentose phosphate pathway (PPP) was downregulated and less NADP (NADPH) was detected, consistent with the high sensitivity to H2O2 and the growth retardation of the ΔphoU2 mutant. The upregulated expression of ATP synthase was consistent with the high intracellular ATP content in the ΔphoU2 mutant, which may have been related to the lower drug tolerance of the ΔphoU2 mutant. This study demonstrates that PhoU2, but not PhoU1, in S. epidermidis regulates bacterial growth, biofilm formation, oxidative stress, and drug tolerance in association with alterations to inorganic phosphate metabolism, the pentose phosphate pathway, galactose metabolism, the tricarboxylic acid (TCA) or citric cycle, glycolysis and gluconeogenesis, and respiratory reactions. IMPORTANCE PhoU is widely conserved throughout the bacterial kingdom and plays an important role in response to stress and metabolic maintenance. In our study, two PhoU homologs were found in S. epidermidis. The function of phoU2, but not phoU1, in S. epidermidis is related to growth, drug tolerance, the oxidative stress response, polyP levels, and ATP accumulation. In addition, phoU2 regulates biofilm formation. Hence, phoU2 is a regulator of both drug tolerance and biofilm formation, which are two bacterial properties that present major challenges to the clinical treatment of infections. Analysis of differential gene expression revealed that phoU2 is involved in fundamental metabolic processes, such as the PPP pathway. These findings indicate that phoU2 is a crucial regulator in S. epidermidis.
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Aguilera-Correa JJ, Conde A, Arenas MA, de-Damborenea JJ, Marin M, Doadrio AL, Esteban J. Bactericidal activity of the Ti-13Nb-13Zr alloy against different species of bacteria related with implant infection. ACTA ACUST UNITED AC 2017; 12:045022. [PMID: 28799523 DOI: 10.1088/1748-605x/aa770c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The Ti-6Al-4V alloy is one of the most commonly used in orthopedic surgery. Despite its advantages, there is an increasing need to use new titanium alloys with no toxic elements and improved biomechanical properties, such as Ti-13Nb-13Zr. Prosthetic joint infections (PJI) are mainly caused by Gram-positive bacteria; however, Gram-negative bacteria are a growing problem due to associated multidrug resistance. In this study, the bacterial adherence and viability on the Ti-13Nb-13Zr alloy have been compared to that of the Ti-6Al-4V alloy using 16 collection and clinical strains of bacterial species related to PJI: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa. When compared with the Ti-6Al-4V alloy, bacterial adherence on the Ti-13Nb-13Zr alloy was significantly higher in most staphylococcal and P. aeruginosa strains and lower for E. coli strains. The proportion of live bacteria was significantly lower for both Gram-negative species on the Ti-13Nb-13Zr alloy than on the Ti-6Al-4V alloy pointing to some bactericidal effect of the Ti-13Nb-13Zr alloy. This bactericidal effect appears to be a consequence of the formation of hydroxyl radicals, since this effect is neutralized when dimethylsulfoxide was added to both the saline solution and water used to wash the stain. The antibacterial effect of the Ti-13Nb-13Zr alloy against Gram-negative bacteria is an interesting property useful for the prevention of PJI caused by these bacteria on this potential alternative to the Ti-6Al-4V alloy for orthopedic surgery.
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Affiliation(s)
- John-Jairo Aguilera-Correa
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, UAM, Av. Reyes Catolicos, 2, E-28040 Madrid, Spain
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Abstract
Bacteria possess molecular biosensors that enable responses to a variety of stressful conditions, including oxidative stress, toxic compounds, and interactions with other organisms, through elaborately coordinated regulation of gene expression. In Escherichia coli and related bacteria, the transcription factor SoxR functions as a sensor of oxidative stress and nitric oxide (NO). SoxR protein contains a [2Fe-2S] cluster essential for its transcription-enhancing activity, which is regulated by redox changes in the [2Fe-2S] cluster. We have explored the mechanistic and structural basis of SoxR proteins function and determined how the chemistry at the [2Fe-2S] cluster causes the subsequent regulatory response. In this Account, I describe our recent achievements in three different areas using physicochemical techniques, primarily pulse radiolysis. First, redox-dependent conformational changes in SoxR-bound DNA were studied by site-specifically replacing selected bases with the fluorescent probes 2-aminopurine and pyrrolocytosine. X-ray analyses of the DNA-SoxR complex in the oxidized state revealed that the DNA structure is distorted in the center regions, resulting in local untwisting of base pairs. However, the inactive, reduced state had remained uncharacterized. We found that reduction of the [2Fe-2S] cluster in the SoxR-DNA complex weakens the fluorescence intensity within a region confined to the central base pairs in the promoter region. Second, the reactions of NO with [2Fe-2S] clusters of E. coli SoxR were analyzed using pulse radiolysis. The transcriptional activation of SoxR in E. coli occurs through direct modification of [2Fe-2S] by NO to form a dinitrosyl iron complex (DNIC). The reaction of NO with [2Fe-2S] cluster of SoxR proceeded nearly quantitatively with concomitant reductive elimination of two equivalents S0 atoms. Intermediate nitrosylation products, however, were too unstable to observe. We found that the conversion proceeds through at least two steps, with the faster phase being the first reaction of the NO molecule with the [2Fe-2S] cluster. The slower reaction with the second equivalent NO molecule, however, was important for the formation of DNIC. Third, to elucidate the differences between the distinct responses of SoxR proteins from two different species, we studied the interaction of E. coli and Pseudomonas aeruginosa SoxR with superoxide anion using a mutagenic approach. Despite the homology between E. coli SoxR and P. aeruginosa SoxR, the function of P. aeruginosa SoxR differs from that of E. coli. The substitution of E. coli SoxR lysine residues, located close to [2Fe-2S] clusters, into P. aeruginosa SoxR dramatically affected the reaction with superoxide anion.
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Affiliation(s)
- Kazuo Kobayashi
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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12
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Abstract
Members of the multiple antibiotic resistance regulator (MarR) family of transcription factors are critical for bacterial cells to respond to chemical signals and to convert such signals into changes in gene activity. Obligate dimers belonging to the winged helix-turn-helix protein family, they are critical for regulation of a variety of functions, including degradation of organic compounds and control of virulence gene expression. The conventional regulatory paradigm is based on a genomic locus in which the gene encoding the MarR protein is divergently oriented from a gene under its control; MarR binding to the intergenic region controls expression of both genes by changing the interaction of RNA polymerase with gene promoters. MarR protein oxidation or binding of a small molecule ligand adversely affects DNA binding, resulting in altered expression of the divergent genes. The generality of this simple paradigm, including the regulation of Escherichia coli MarR by direct binding of antibiotics, has been challenged by reports published in recent years. In addition, structural and biochemical analyses of ligand binding to numerous MarR homologs are converging to identify a shared ligand-binding "hot-spot". This review highlights recent research advances that point to shared features, yet at the same time highlights the remarkable flexibility with which members of this protein family implement responses to inducing signals. A more comprehensive understanding of protein function will pave the way towards the development of both antibacterial agents and biosensors that are based on MarR family proteins.
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Affiliation(s)
- Dinesh K Deochand
- a Department of Biological Sciences , Louisiana State University , Baton Rouge , LA , USA
| | - Anne Grove
- a Department of Biological Sciences , Louisiana State University , Baton Rouge , LA , USA
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13
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Liu G, Liu X, Xu H, Liu X, Zhou H, Huang Z, Gan J, Chen H, Lan L, Yang CG. Structural Insights into the Redox-Sensing Mechanism of MarR-Type Regulator AbfR. J Am Chem Soc 2017; 139:1598-1608. [PMID: 28086264 DOI: 10.1021/jacs.6b11438] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
As a master redox-sensing MarR-family transcriptional regulator, AbfR participates in oxidative stress responses and virulence regulations in Staphylococcus epidermidis. Here, we present structural insights into the DNA-binding mechanism of AbfR in different oxidation states by determining the X-ray crystal structures of a reduced-AbfR/DNA complex, an overoxidized (Cys13-SO2H and Cys13-SO3H) AbfR/DNA, and 2-disulfide cross-linked AbfR dimer. Together with biochemical analyses, our results suggest that the redox regulation of AbfR-sensing displays two novel features: (i) the reversible disulfide modification, but not the irreversible overoxidation, significantly abolishes the DNA-binding ability of the AbfR repressor; (ii) either 1-disulfide cross-linked or 2-disulfide cross-linked AbfR dimer is biologically significant. The overoxidized species of AbfR, resembling the reduced AbfR in conformation and retaining the DNA-binding ability, does not exist in biologically significant concentrations, however. The 1-disulfide cross-linked modification endows AbfR with significantly weakened capability for DNA-binding. The 2-disulfide cross-linked AbfR adopts a very "open" conformation that is incompatible with DNA-binding. Overall, the concise oxidation chemistry of the redox-active cysteine allows AbfR to sense and respond to oxidative stress correctly and efficiently.
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Affiliation(s)
- Guijie Liu
- Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai 201203, China.,University of Chinese Academy of Sciences , Beijing 100049, China
| | - Xing Liu
- Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai 201203, China.,CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai 201203, China
| | - Hongjiao Xu
- Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai 201203, China.,University of Chinese Academy of Sciences , Beijing 100049, China
| | - Xichun Liu
- Coordination Chemistry Institute and State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, China
| | - Hu Zhou
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai 201203, China
| | - Zhen Huang
- Department of Chemistry, Georgia State University , Atlanta, Georgia 30303, United States
| | - Jianhua Gan
- School of Life Sciences, Fudan University , Shanghai 200433, China
| | - Hao Chen
- Coordination Chemistry Institute and State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, China
| | - Lefu Lan
- Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai 201203, China
| | - Cai-Guang Yang
- Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai 201203, China
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14
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Fujikawa M, Kobayashi K, Tsutsui Y, Tanaka T, Kozawa T. Rational Tuning of Superoxide Sensitivity in SoxR, the [2Fe-2S] Transcription Factor: Implications of Species-Specific Lysine Residues. Biochemistry 2017; 56:403-410. [DOI: 10.1021/acs.biochem.6b01096] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Mayu Fujikawa
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
| | - Kazuo Kobayashi
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
| | - Yuko Tsutsui
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
| | - Takahiro Tanaka
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
| | - Takahiro Kozawa
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
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15
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Rittiroongrad S, Charoenlap N, Giengkam S, Vattanaviboon P, Mongkolsuk S. Agrobacterium tumefaciens estC, Encoding an Enzyme Containing Esterase Activity, Is Regulated by EstR, a Regulator in the MarR Family. PLoS One 2016; 11:e0168791. [PMID: 28036400 PMCID: PMC5201249 DOI: 10.1371/journal.pone.0168791] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 12/06/2016] [Indexed: 11/18/2022] Open
Abstract
Analysis of the A. tumefaciens genome revealed estC, which encodes an esterase located next to its transcriptional regulator estR, a regulator of esterase in the MarR family. Inactivation of estC results in a small increase in the resistance to organic hydroperoxides, whereas a high level of expression of estC from an expression vector leads to a reduction in the resistance to organic hydroperoxides and menadione. The estC gene is transcribed divergently from its regulator, estR. Expression analysis showed that only high concentrations of cumene hydroperoxide (CHP, 1 mM) induced expression of both genes in an EstR-dependent manner. The EstR protein acts as a CHP sensor and a transcriptional repressor of both genes. EstR specifically binds to the operator sites OI and OII overlapping the promoter elements of estC and estR. This binding is responsible for transcription repression of both genes. Exposure to organic hydroperoxide results in oxidation of the sensing cysteine (Cys16) residue of EstR, leading to a release of the oxidized repressor from the operator sites, thereby allowing transcription and high levels of expression of both genes. The estC is the first organic hydroperoxide-inducible esterase-encoding gene in alphaproteobacteria.
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Affiliation(s)
- Surawach Rittiroongrad
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
- Department of Biotechnology, and Center of Emerging Bacterial Infection, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Nisanart Charoenlap
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology, Bangkok, Thailand
| | - Suparat Giengkam
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Paiboon Vattanaviboon
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology, Bangkok, Thailand
- Program in Applied Biological Sciences: Environmental Health, Chulabhorn Graduate Institute, Bangkok, Thailand
| | - Skorn Mongkolsuk
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
- Department of Biotechnology, and Center of Emerging Bacterial Infection, Faculty of Science, Mahidol University, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology, Bangkok, Thailand
- Program in Applied Biological Sciences: Environmental Health, Chulabhorn Graduate Institute, Bangkok, Thailand
- * E-mail:
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16
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Pascoe B, Méric G, Murray S, Yahara K, Mageiros L, Bowen R, Jones NH, Jeeves RE, Lappin-Scott HM, Asakura H, Sheppard SK. Enhanced biofilm formation and multi-host transmission evolve from divergent genetic backgrounds in Campylobacter jejuni. Environ Microbiol 2015; 17:4779-89. [PMID: 26373338 PMCID: PMC4862030 DOI: 10.1111/1462-2920.13051] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 09/07/2015] [Accepted: 09/08/2015] [Indexed: 02/01/2023]
Abstract
Multicellular biofilms are an ancient bacterial adaptation that offers a protective environment for survival in hostile habitats. In microaerophilic organisms such as Campylobacter, biofilms play a key role in transmission to humans as the bacteria are exposed to atmospheric oxygen concentrations when leaving the reservoir host gut. Genetic determinants of biofilm formation differ between species, but little is known about how strains of the same species achieve the biofilm phenotype with different genetic backgrounds. Our approach combines genome‐wide association studies with traditional microbiology techniques to investigate the genetic basis of biofilm formation in 102 Campylobacter jejuni isolates. We quantified biofilm formation among the isolates and identified hotspots of genetic variation in homologous sequences that correspond to variation in biofilm phenotypes. Thirteen genes demonstrated a statistically robust association including those involved in adhesion, motility, glycosylation, capsule production and oxidative stress. The genes associated with biofilm formation were different in the host generalist ST‐21 and ST‐45 clonal complexes, which are frequently isolated from multiple host species and clinical samples. This suggests the evolution of enhanced biofilm from different genetic backgrounds and a possible role in colonization of multiple hosts and transmission to humans.
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Affiliation(s)
- Ben Pascoe
- College of Medicine, Institute of Life Science, Swansea University, Swansea, UK.,MRC CLIMB Consortium, Institute of Life Science, Swansea University, Swansea, UK
| | - Guillaume Méric
- College of Medicine, Institute of Life Science, Swansea University, Swansea, UK
| | - Susan Murray
- College of Medicine, Institute of Life Science, Swansea University, Swansea, UK
| | - Koji Yahara
- College of Medicine, Institute of Life Science, Swansea University, Swansea, UK.,Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Leonardos Mageiros
- College of Medicine, Institute of Life Science, Swansea University, Swansea, UK
| | - Ryan Bowen
- College of Medicine, Institute of Life Science, Swansea University, Swansea, UK
| | - Nathan H Jones
- College of Medicine, Institute of Life Science, Swansea University, Swansea, UK
| | - Rose E Jeeves
- College of Medicine, Institute of Life Science, Swansea University, Swansea, UK
| | | | - Hiroshi Asakura
- Division of Biomedical Food Research, National Institute of Health Sciences, Tokyo, Japan
| | - Samuel K Sheppard
- College of Medicine, Institute of Life Science, Swansea University, Swansea, UK.,MRC CLIMB Consortium, Institute of Life Science, Swansea University, Swansea, UK.,Department of Zoology, University of Oxford, Oxford, UK
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17
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Xue T, Ni J, Shang F, Chen X, Zhang M. Autoinducer-2 increases biofilm formation via an ica- and bhp-dependent manner in Staphylococcus epidermidis RP62A. Microbes Infect 2015; 17:345-52. [PMID: 25637952 DOI: 10.1016/j.micinf.2015.01.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/14/2015] [Accepted: 01/14/2015] [Indexed: 10/24/2022]
Abstract
Staphylococcus epidermidis has become the most common cause of nosocomial bacteraemia and the principal organism responsible for indwelling medical device -associated infections. Its pathogenicity is mainly due to its ability to form biofilms on the implanted medical devices. Biofilm formation is a quorum-sensing (QS)-dependent process controlled by autoinducers, which are signalling molecules. Here, we investigated the function of the autoinducer-2 (AI-2) QS system, especially the influence of AI-2 on biofilm formation in S. epidermidis RP62A. Results showed that the addition of AI-2 leads to a significant increase in biofilm formation, in contrast with previous studies which showed that AI-2 limits biofilm formation in Staphylococci. We found that AI-2 increases biofilm formation by enhancing the transcription of the ica operon, which is a known component in the AI-2-regulated biofilm pathway. In addition, we first observed that the transcript level of bhp, which encodes a biofilm-associated protein, was also increased following the addition of AI-2. Furthermore, we found that, among the known biofilm regulator genes (icaR, sigB, rbsU, sarA, sarX, sarZ, clpP, agrA, abfR, arlRS, saeRS), only icaR can be regulated by AI-2, suggesting that AI-2 may regulate biofilm formation by an icaR-dependent mechanism in S. epidermidis RP62A.
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Affiliation(s)
- Ting Xue
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China.
| | - Jingtian Ni
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Fei Shang
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Xiaolin Chen
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Ming Zhang
- School of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, China
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18
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Dhall S, Do D, Garcia M, Wijesinghe DS, Brandon A, Kim J, Sanchez A, Lyubovitsky J, Gallagher S, Nothnagel EA, Chalfant CE, Patel RP, Schiller N, Martins-Green M. A novel model of chronic wounds: importance of redox imbalance and biofilm-forming bacteria for establishment of chronicity. PLoS One 2014; 9:e109848. [PMID: 25313558 PMCID: PMC4196950 DOI: 10.1371/journal.pone.0109848] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 09/03/2014] [Indexed: 12/20/2022] Open
Abstract
Chronic wounds have a large impact on health, affecting ∼6.5 M people and costing ∼$25B/year in the US alone. We previously discovered that a genetically modified mouse model displays impaired healing similar to problematic wounds in humans and that sometimes the wounds become chronic. Here we show how and why these impaired wounds become chronic, describe a way whereby we can drive impaired wounds to chronicity at will and propose that the same processes are involved in chronic wound development in humans. We hypothesize that exacerbated levels of oxidative stress are critical for initiation of chronicity. We show that, very early after injury, wounds with impaired healing contain elevated levels of reactive oxygen and nitrogen species and, much like in humans, these levels increase with age. Moreover, the activity of anti-oxidant enzymes is not elevated, leading to buildup of oxidative stress in the wound environment. To induce chronicity, we exacerbated the redox imbalance by further inhibiting the antioxidant enzymes and by infecting the wounds with biofilm-forming bacteria isolated from the chronic wounds that developed naturally in these mice. These wounds do not re-epithelialize, the granulation tissue lacks vascularization and interstitial collagen fibers, they contain an antibiotic-resistant mixed bioflora with biofilm-forming capacity, and they stay open for several weeks. These findings are highly significant because they show for the first time that chronic wounds can be generated in an animal model effectively and consistently. The availability of such a model will significantly propel the field forward because it can be used to develop strategies to regain redox balance that may result in inhibition of biofilm formation and result in restoration of healthy wound tissue. Furthermore, the model can lead to the understanding of other fundamental mechanisms of chronic wound development that can potentially lead to novel therapies.
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Affiliation(s)
- Sandeep Dhall
- Departments of Cell Biology and Neuroscience, University of California Riverside, Riverside, California, United States of America
- Bioengineering Interdepartmental Graduate Program, University of California Riverside, Riverside, California, United States of America
| | - Danh Do
- Division of Biomedical Sciences, University of California Riverside, Riverside, California, United States of America
| | - Monika Garcia
- Departments of Cell Biology and Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Dayanjan Shanaka Wijesinghe
- Hunter Holmes McGuire Veterans Administration Medical Center, Richmond, Virginia, United States of America
- Department of Biochemistry & Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Virginia Commonwealth University Reanimation Engineering Science Center, Richmond, Virginia, United States of America
- The Massey Cancer Center, Richmond, Virginia, United States of America
| | - Angela Brandon
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jane Kim
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California, United States of America
| | - Antonio Sanchez
- Department of Product Technology, UVP, LLC, an Analytik Jena Company, Upland, California, United States of America
| | - Julia Lyubovitsky
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
| | - Sean Gallagher
- Department of Product Technology, UVP, LLC, an Analytik Jena Company, Upland, California, United States of America
| | - Eugene A. Nothnagel
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California, United States of America
| | - Charles E. Chalfant
- Hunter Holmes McGuire Veterans Administration Medical Center, Richmond, Virginia, United States of America
- Department of Biochemistry & Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Virginia Commonwealth University Reanimation Engineering Science Center, Richmond, Virginia, United States of America
- The Massey Cancer Center, Richmond, Virginia, United States of America
| | - Rakesh P. Patel
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Neal Schiller
- Division of Biomedical Sciences, University of California Riverside, Riverside, California, United States of America
| | - Manuela Martins-Green
- Departments of Cell Biology and Neuroscience, University of California Riverside, Riverside, California, United States of America
- Bioengineering Interdepartmental Graduate Program, University of California Riverside, Riverside, California, United States of America
- * E-mail:
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19
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Cao Q, Wang Y, Chen F, Xia Y, Lou J, Zhang X, Yang N, Sun X, Zhang Q, Zhuo C, Huang X, Deng X, Yang CG, Ye Y, Zhao J, Wu M, Lan L. A novel signal transduction pathway that modulates rhl quorum sensing and bacterial virulence in Pseudomonas aeruginosa. PLoS Pathog 2014; 10:e1004340. [PMID: 25166864 PMCID: PMC4148453 DOI: 10.1371/journal.ppat.1004340] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 07/15/2014] [Indexed: 01/10/2023] Open
Abstract
The rhl quorum-sensing (QS) system plays critical roles in the pathogenesis of P. aeruginosa. However, the regulatory effects that occur directly upstream of the rhl QS system are poorly understood. Here, we show that deletion of gene encoding for the two-component sensor BfmS leads to the activation of its cognate response regulator BfmR, which in turn directly binds to the promoter and decreases the expression of the rhlR gene that encodes the QS regulator RhlR, causing the inhibition of the rhl QS system. In the absence of bfmS, the Acka-Pta pathway can modulate the regulatory activity of BfmR. In addition, BfmS tunes the expression of 202 genes that comprise 3.6% of the P. aeruginosa genome. We further demonstrate that deletion of bfmS causes substantially reduced virulence in lettuce leaf, reduced cytotoxicity, enhanced invasion, and reduced bacterial survival during acute mouse lung infection. Intriguingly, specific missense mutations, which occur naturally in the bfmS gene in P. aeruginosa cystic fibrosis (CF) isolates such as DK2 strains and RP73 strain, can produce BfmS variants (BfmSL181P, BfmSL181P/E376Q, and BfmSR393H) that no longer repress, but instead activate BfmR. As a result, BfmS variants, but not the wild-type BfmS, inhibit the rhl QS system. This study thus uncovers a previously unexplored signal transduction pathway, BfmS/BfmR/RhlR, for the regulation of rhl QS in P. aeruginosa. We propose that BfmRS TCS may have an important role in the regulation and evolution of P. aeruginosa virulence during chronic infection in CF lungs. The rhl quorum-sensing (QS) system allows P. aeruginosa to regulate diverse metabolic adaptations and virulence. However, how rhl QS system is regulated remains largely unknown. Here, we report that two-component sensor BfmS controls rhl QS system by repressing its cognate response regulator BfmR, which directly suppresses the expression of rhl QS regulator RhlR gene and reduces the production of QS signal molecule N-butanoyl-L-homoserine lactone (C4-HSL). We find that BfmS is critical to the ability of P. aeruginosa to modulate the expression of virulence-associated traits and adapt to the host. Intriguingly, although wild-type BfmS is a repressor of BfmR, naturally occurring missense mutation (L181P, L181P/E376Q, or R393H) can convert its function from a repressor to an activator of BfmR, leading to BfmR activation, which in turn reduces the level of rhl QS signal C4-HSL. These results, therefore, provide important and novel insight into the regulation and evolution of P. aeruginosa virulence.
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Affiliation(s)
- Qiao Cao
- Hainan University, Haikou, Hainan, China
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yue Wang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Institute of Chemistry and BioMedical Sciences, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Feifei Chen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yongjie Xia
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jingyu Lou
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xue Zhang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Nana Yang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiaoxu Sun
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Qin Zhang
- State Key Laboratory of Respiratory Diseases and the First Affiliated Hospital of Guangzhou Medical College, Guangzhou, China
| | - Chao Zhuo
- State Key Laboratory of Respiratory Diseases and the First Affiliated Hospital of Guangzhou Medical College, Guangzhou, China
| | - Xi Huang
- Hainan University, Haikou, Hainan, China
| | - Xin Deng
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois, United States of America
| | - Cai-Guang Yang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yan Ye
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
| | - Jing Zhao
- Institute of Chemistry and BioMedical Sciences, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
- * E-mail: (JZ); (MW); (LL)
| | - Min Wu
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
- * E-mail: (JZ); (MW); (LL)
| | - Lefu Lan
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (JZ); (MW); (LL)
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20
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Mhatre E, Monterrosa RG, Kovács AT. From environmental signals to regulators: modulation of biofilm development in Gram-positive bacteria. J Basic Microbiol 2014; 54:616-32. [PMID: 24771632 DOI: 10.1002/jobm.201400175] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 03/30/2014] [Indexed: 12/22/2022]
Abstract
Bacterial lifestyle is influenced by environmental signals, and many differentiation processes in bacteria are governed by the threshold concentrations of molecules present in their niche. Biofilm is one such example where bacteria in their sessile state adapt to a lifestyle that causes several adaptive alterations in the population. Here, a brief overview is given on a variety of environmental signals that bias biofilm development in Gram-positive bacteria, including nutrient conditions, self- and heterologously produced substances, like quorum sensing and host produced molecules. The Gram-positive model organism, Bacillus subtilis is a superb example to illustrate how distinct signals activate sensor proteins that integrate the environmental signals towards global regulators related to biofilm formation. The role of reduced oxygen level, polyketides, antimicrobials, plant secreted carbohydrates, plant cell derived polymers, glycerol, and osmotic conditions are discussed during the transcriptional activation of biofilm related genes in B. subtilis.
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Affiliation(s)
- Eisha Mhatre
- Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
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