1
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Mayo-Pérez S, Gama-Martínez Y, Dávila S, Rivera N, Hernández-Lucas I. LysR-type transcriptional regulators: state of the art. Crit Rev Microbiol 2023:1-33. [PMID: 37635411 DOI: 10.1080/1040841x.2023.2247477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 08/03/2023] [Accepted: 08/08/2023] [Indexed: 08/29/2023]
Abstract
The LysR-type transcriptional regulators (LTTRs) are DNA-binding proteins present in bacteria, archaea, and in algae. Knowledge about their distribution, abundance, evolution, structural organization, transcriptional regulation, fundamental roles in free life, pathogenesis, and bacteria-plant interaction has been generated. This review focuses on these aspects and provides a current picture of LTTR biology.
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Affiliation(s)
- S Mayo-Pérez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Y Gama-Martínez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - S Dávila
- Centro de Investigación en Dinámica Celular, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - N Rivera
- IPN: CICATA, Unidad Morelos del Instituto Politécnico Nacional, Atlacholoaya, Mexico
| | - I Hernández-Lucas
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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2
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Lensmire JM, Wischer MR, Kraemer-Zimpel C, Kies PJ, Sosinski L, Ensink E, Dodson JP, Shook JC, Delekta PC, Cooper CC, Havlichek DH, Mulks MH, Lunt SY, Ravi J, Hammer ND. The glutathione import system satisfies the Staphylococcus aureus nutrient sulfur requirement and promotes interspecies competition. PLoS Genet 2023; 19:e1010834. [PMID: 37418503 PMCID: PMC10355420 DOI: 10.1371/journal.pgen.1010834] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 06/21/2023] [Indexed: 07/09/2023] Open
Abstract
Sulfur is an indispensable element for bacterial proliferation. Prior studies demonstrated that the human pathogen Staphylococcus aureus utilizes glutathione (GSH) as a source of nutrient sulfur; however, mechanisms of GSH acquisition are not defined. Here, we identify a five-gene locus comprising a putative ABC-transporter and predicted γ-glutamyl transpeptidase (ggt) that promotes S. aureus proliferation in medium supplemented with either reduced or oxidized GSH (GSSG) as the sole source of nutrient sulfur. Based on these phenotypes, we name this transporter operon the glutathione import system (gisABCD). Ggt is encoded within the gisBCD operon, and we show that the enzyme is capable of liberating glutamate using either GSH or GSSG as substrates, demonstrating it is a bona fide γ-glutamyl transpeptidase. We also determine that Ggt is expressed in the cytoplasm, representing only the second example of cytoplasmic Ggt localization, the other being Neisseria meningitidis. Bioinformatic analyses revealed that Staphylococcus species closely related to S. aureus encode GisABCD-Ggt homologs. However, homologous systems were not detected in Staphylococcus epidermidis. Consequently, we establish that GisABCD-Ggt provides a competitive advantage for S. aureus over S. epidermidis in a GSH- and GSSG-dependent manner. Overall, this study describes the discovery of a nutrient sulfur acquisition system in S. aureus that targets GSSG in addition to GSH and promotes competition against other staphylococci commonly associated with the human microbiota.
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Affiliation(s)
- Joshua M Lensmire
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Michael R Wischer
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Cristina Kraemer-Zimpel
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Paige J Kies
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Lo Sosinski
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan, United States of America
| | - Elliot Ensink
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, United States of America
| | - Jack P Dodson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - John C Shook
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Phillip C Delekta
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Christopher C Cooper
- Department of Medicine, Division of Infectious Disease, Michigan State University, East Lansing, Michigan, United States of America
| | - Daniel H Havlichek
- Department of Medicine, Division of Infectious Disease, Michigan State University, East Lansing, Michigan, United States of America
| | - Martha H Mulks
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Sophia Y Lunt
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, United States of America
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, United States of America
| | - Janani Ravi
- Department of Biomedical Informatics, Center for Health Artificial Intelligence, University of Colorado Anschutz, Aurora, Colorado, United States of America
| | - Neal D Hammer
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
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3
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Abstract
The nasopharynx and the skin are the major oxygen-rich anatomical sites for colonization by the human pathogen Streptococcus pyogenes (group A Streptococcus [GAS]). To establish infection, GAS must survive oxidative stress generated during aerobic metabolism and the release of reactive oxygen species (ROS) by host innate immune cells. Glutathione is the major host antioxidant molecule, while GAS is glutathione auxotrophic. Here, we report the molecular characterization of the ABC transporter substrate binding protein GshT in the GAS glutathione salvage pathway. We demonstrate that glutathione uptake is critical for aerobic growth of GAS and that impaired import of glutathione induces oxidative stress that triggers enhanced production of the reducing equivalent NADPH. Our results highlight the interrelationship between glutathione assimilation, carbohydrate metabolism, virulence factor production, and innate immune evasion. Together, these findings suggest an adaptive strategy employed by extracellular bacterial pathogens to exploit host glutathione stores for their own benefit.
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4
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Pan X, Tang M, You J, Osire T, Sun C, Fu W, Yi G, Yang T, Yang ST, Rao Z. PsrA is a novel regulator contributes to antibiotic synthesis, bacterial virulence, cell motility and extracellular polysaccharides production in Serratia marcescens. Nucleic Acids Res 2021; 50:127-148. [PMID: 34893884 PMCID: PMC8754645 DOI: 10.1093/nar/gkab1186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/13/2021] [Accepted: 12/03/2021] [Indexed: 12/23/2022] Open
Abstract
Serratia marcescens is a Gram-negative bacterium of the Enterobacteriaceae family that can produce numbers of biologically active secondary metabolites. However, our understanding of the regulatory mechanisms behind secondary metabolites biosynthesis in S. marcescens remains limited. In this study, we identified an uncharacterized LysR family transcriptional regulator, encoding gene BVG90_12635, here we named psrA, that positively controlled prodigiosin synthesis in S. marcescens. This phenotype corresponded to PsrA positive control of transcriptional of the prodigiosin-associated pig operon by directly binding to a regulatory binding site (RBS) and an activating binding site (ABS) in the promoter region of the pig operon. We demonstrated that L-proline is an effector for the PsrA, which enhances the binding affinity of PsrA to its target promoters. Using transcriptomics and further experiments, we show that PsrA indirectly regulates pleiotropic phenotypes, including serrawettin W1 biosynthesis, extracellular polysaccharide production, biofilm formation, swarming motility and T6SS-mediated antibacterial activity in S. marcescens. Collectively, this study proposes that PsrA is a novel regulator that contributes to antibiotic synthesis, bacterial virulence, cell motility and extracellular polysaccharides production in S. marcescens and provides important clues for future studies exploring the function of the PsrA and PsrA-like proteins which are widely present in many other bacteria.
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Affiliation(s)
- Xuewei Pan
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Mi Tang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jiajia You
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Tolbert Osire
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Changhao Sun
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Weilai Fu
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China.,Fujian Dabeinong Aquatic Sci. & Tech. Co., Ltd., Zhangzhou 363500, China
| | - Ganfeng Yi
- Fujian Dabeinong Aquatic Sci. & Tech. Co., Ltd., Zhangzhou 363500, China
| | - Taowei Yang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Shang-Tian Yang
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
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5
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Li K, Wu G, Liao Y, Zeng Q, Wang H, Liu F. RpoN1 and RpoN2 play different regulatory roles in virulence traits, flagellar biosynthesis, and basal metabolism in Xanthomonas campestris. MOLECULAR PLANT PATHOLOGY 2020; 21:907-922. [PMID: 32281725 PMCID: PMC7280030 DOI: 10.1111/mpp.12938] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 05/08/2023]
Abstract
Homologous regulatory factors are widely present in bacteria, but whether homologous regulators synergistically or differentially regulate different biological functions remains mostly unknown. Here, we report that the homologous regulators RpoN1 and RpoN2 of the plant pathogen Xanthomonas campestris pv. campestris (Xcc) play different regulatory roles with respect to virulence traits, flagellar biosynthesis, and basal metabolism. RpoN2 directly regulated Xcc fliC and fliQ to modulate flagellar synthesis in X. campestris, thus affecting the swimming motility of X. campestris. Mutation of rpoN2 resulted in reduced production of biofilms and extracellular polysaccharides in Xcc. These defects may together cause reduced virulence of the rpoN2 mutant against the host plant. Moreover, we demonstrated that RpoN1 could regulate branched-chain fatty acid production and modulate the synthesis of diffusible signal factor family quorum sensing signals. Although RpoN1 and RpoN2 are homologues, the regulatory roles and biological functions of these proteins were not interchangeable. Overall, our report provides new insights into the two different molecular roles that form the basis for the transcriptional specialization of RpoN homologues.
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Affiliation(s)
- Kaihuai Li
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | - Guichun Wu
- Institute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjingChina
| | - Yuling Liao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouChina
| | - Quan Zeng
- Department of Plant Pathology and EcologyThe Connecticut Agricultural Experiment StationNew HavenCTUSA
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouChina
| | - Fengquan Liu
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
- Institute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjingChina
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6
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Hernandez-Valdes JA, van Gestel J, Kuipers OP. A riboswitch gives rise to multi-generational phenotypic heterogeneity in an auxotrophic bacterium. Nat Commun 2020; 11:1203. [PMID: 32139702 PMCID: PMC7058034 DOI: 10.1038/s41467-020-15017-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 02/13/2020] [Indexed: 12/26/2022] Open
Abstract
Auxotrophy, the inability to produce an organic compound essential for growth, is widespread among bacteria. Auxotrophic bacteria rely on transporters to acquire these compounds from their environment. Here, we study the expression of both low- and high-affinity transporters of the costly amino acid methionine in an auxotrophic lactic acid bacterium, Lactococcus lactis. We show that the high-affinity transporter (Met-transporter) is heterogeneously expressed at low methionine concentrations, resulting in two isogenic subpopulations that sequester methionine in different ways: one subpopulation primarily relies on the high-affinity transporter (high expression of the Met-transporter) and the other subpopulation primarily relies on the low-affinity transporter (low expression of the Met-transporter). The phenotypic heterogeneity is remarkably stable, inherited for tens of generations, and apparent at the colony level. This heterogeneity results from a T-box riboswitch in the promoter region of the met operon encoding the high-affinity Met-transporter. We hypothesize that T-box riboswitches, which are commonly found in the Lactobacillales, may play as-yet unexplored roles in the predominantly auxotrophic lifestyle of these bacteria.
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Affiliation(s)
- Jhonatan A Hernandez-Valdes
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, Netherlands
| | - Jordi van Gestel
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, Netherlands.
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7
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Chen X, Liu C, Peng X, He Y, Liu H, Song Y, Xiong K, Zou L. Sortase A‐mediated modification of the
Streptococcus mutans
transcriptome and virulence traits. Mol Oral Microbiol 2019; 34:219-233. [PMID: 31342653 DOI: 10.1111/omi.12266] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 02/05/2023]
Affiliation(s)
- Xuan Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Chengcheng Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
- Department of Periodontics West China Hospital of Stomatology, Sichuan University Chengdu China
| | - Xian Peng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Yuanli He
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Haixia Liu
- Stomatological Hospital of Chongqing Medical University Chongqing China
| | - Ying Song
- Stomatological Hospital of Chongqing Medical University Chongqing China
| | - Kaixin Xiong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
| | - Ling Zou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases Sichuan University Chengdu China
- Department of Conservation Dentistry and Endodontics West China Hospital of Stomatology, Sichuan University Chengdu China
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8
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Scharnow AM, Solinski AE, Wuest WM. Targeting S. mutans biofilms: a perspective on preventing dental caries. MEDCHEMCOMM 2019; 10:1057-1067. [PMID: 31391878 PMCID: PMC6644389 DOI: 10.1039/c9md00015a] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/12/2019] [Indexed: 02/06/2023]
Abstract
The prevalence of biofilm diseases, and dental caries in particular, have encouraged extensive research on S. mutans biofilms, including methods of preventing its formation. Numerous small molecules with specific anti-biofilm activity against this pathogen have been isolated and synthesized. Generally, these molecules can be characterized into three categories: sucrose-dependent anti-adhesion, sucrose-independent anti-adhesion and cellular signaling interference. This review aims to provide an overview of the current small molecule strategies used for targeting S. mutans biofilms, and a perspective of the future for the field.
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Affiliation(s)
- Amber M Scharnow
- Emory University , Chemistry Department , 1515 Dickey Dr , Atlanta , GA 30322 , USA .
| | - Amy E Solinski
- Emory University , Chemistry Department , 1515 Dickey Dr , Atlanta , GA 30322 , USA .
| | - William M Wuest
- Emory University , Chemistry Department , 1515 Dickey Dr , Atlanta , GA 30322 , USA .
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9
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Kondoh M, Hirasawa T. L-Cysteine production by metabolically engineered Corynebacterium glutamicum. Appl Microbiol Biotechnol 2019; 103:2609-2619. [PMID: 30729285 DOI: 10.1007/s00253-019-09663-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/20/2019] [Accepted: 01/22/2019] [Indexed: 11/25/2022]
Abstract
L-Cysteine is a commercially important amino acid. Here, we report the construction of L-cysteine-producing Corynebacterium glutamicum using a metabolic engineering approach. L-Serine O-acetyltransferase (SAT), encoded by cysE gene, is a key enzyme of L-cysteine biosynthesis, because of its feedback inhibition by L-cysteine. Therefore, we introduced a mutation into the C. glutamicum cysE gene, which appeared to desensitize SAT against feedback inhibition by L-cysteine. We successfully produced L-cysteine by overexpressing this mutant cysE gene in C. glutamicum, while the wild-type strain scarcely produced L-cysteine. To enhance the biosynthesis of L-serine (a substrate for SAT), a mutant serA gene, encoding D-3-phosphoglycerate dehydrogenase to desensitize it against feedback inhibition by L-serine, was additionally overexpressed in the mutant cysE-overexpressing strain and its L-cysteine production was indeed improved. Moreover, we disrupted the ldh gene encoding L-lactate dehydrogenase and the aecD gene encoding cysteine desulfhydrase to prevent the formation of lactic acid as a by-product and degradation of L-cysteine produced at the stationary phase, respectively, which resulted in enhanced L-cysteine production. However, since the concentration of L-cysteine produced still decreased at the stationary phase despite the aecD disruption, NCgl2463 encoding a possible cystine importer protein was further disrupted to prevent cystine import, because the produced L-cysteine is immediately oxidized to cystine. As a result, the time before the start of the decrease in L-cysteine concentration was successfully prolonged. Approximately 200 mg/L of L-cysteine production was achieved by overexpression of mutant cysE and serA genes and disruption of aecD and NCgl2463 genes in C. glutamicum.
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Affiliation(s)
- Mariko Kondoh
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midoriku, Yokohama, Kanagawa, 226-8501, Japan
| | - Takashi Hirasawa
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midoriku, Yokohama, Kanagawa, 226-8501, Japan.
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10
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Ku JW, Gan YH. Modulation of bacterial virulence and fitness by host glutathione. Curr Opin Microbiol 2018; 47:8-13. [PMID: 30396015 DOI: 10.1016/j.mib.2018.10.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/02/2018] [Accepted: 10/05/2018] [Indexed: 01/26/2023]
Abstract
Glutathione is a low molecular weight thiol that is important for maintaining intracellular redox homeostasis. Some bacteria are able to import exogenous glutathione as a nutritional source and to counter oxidative stress. In cytosolic pathogens Burkholderia pseudomallei and Listeria monocytogenes, host glutathione regulates bacterial virulence. In B. pseudomallei, glutathione activates the membrane-bound histidine kinase sensor VirA that leads to activation of the Type VI Secretion System. In L. monocytogenes, host glutathione leads to the binding of bacterial glutathione to the master virulence regulator PrfA as an allosteric activator. Glutathione can also modulate virulence factors to control their activity by S-glutathionylation. Thus, host glutathione acts as a spacio-temporal cue for some pathogens to switch on their virulence programs at the right time and place.
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Affiliation(s)
- Joanne Wk Ku
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yunn-Hwen Gan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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11
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Koentjoro MP, Adachi N, Senda M, Ogawa N, Senda T. Crystal structure of theDNA‐binding domain of the LysR‐type transcriptional regulator CbnR in complex with aDNAfragment of the recognition‐binding site in the promoter region. FEBS J 2018; 285:977-989. [DOI: 10.1111/febs.14380] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/17/2017] [Accepted: 01/08/2018] [Indexed: 11/29/2022]
Affiliation(s)
| | - Naruhiko Adachi
- Structural Biology Research Center Photon Factory Institute of Materials Structure Science High Energy Accelerator Research Organization (KEK) Tsukuba Japan
- Department of Materials Structure Science Accelerator Science The Graduate University of Advanced Studies (Soken‐dai) Tsukuba Japan
- Precursory Research for Embryonic Science and Technology Japan Science and Technology Agency Tsukuba Japan
| | - Miki Senda
- Structural Biology Research Center Photon Factory Institute of Materials Structure Science High Energy Accelerator Research Organization (KEK) Tsukuba Japan
| | - Naoto Ogawa
- The United Graduate School of Agricultural Science Gifu University Japan
- Department of Applied Life Sciences Faculty of Agriculture Shizuoka University Japan
| | - Toshiya Senda
- Structural Biology Research Center Photon Factory Institute of Materials Structure Science High Energy Accelerator Research Organization (KEK) Tsukuba Japan
- Department of Materials Structure Science Accelerator Science The Graduate University of Advanced Studies (Soken‐dai) Tsukuba Japan
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12
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Couvigny B, Lapaque N, Rigottier-Gois L, Guillot A, Chat S, Meylheuc T, Kulakauskas S, Rohde M, Mistou MY, Renault P, Doré J, Briandet R, Serror P, Guédon E. Three glycosylated serine-rich repeat proteins play a pivotal role in adhesion and colonization of the pioneer commensal bacterium,Streptococcus salivarius. Environ Microbiol 2017; 19:3579-3594. [DOI: 10.1111/1462-2920.13853] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 01/25/2023]
Affiliation(s)
- Benoit Couvigny
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Nicolas Lapaque
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Lionel Rigottier-Gois
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Alain Guillot
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Sophie Chat
- INRA, Plateforme MIMA2; Jouy-en-josas France
| | - Thierry Meylheuc
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
- INRA, Plateforme MIMA2; Jouy-en-josas France
| | - Saulius Kulakauskas
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Manfred Rohde
- HZI, Helmholtz Centre for Infection Research; Braunschweig Germany
| | - Michel-Yves Mistou
- Laboratory for Food Safety; Université Paris-Est, ANSES; Maisons-Alfort France
| | - Pierre Renault
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Joel Doré
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Romain Briandet
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Pascale Serror
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Eric Guédon
- STLO, UMR1253, INRA, Agrocampus Ouest; Rennes France
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13
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Afzal M, Manzoor I, Kuipers OP, Shafeeq S. Cysteine-Mediated Gene Expression and Characterization of the CmbR Regulon in Streptococcus pneumoniae. Front Microbiol 2016; 7:1929. [PMID: 27990139 PMCID: PMC5131005 DOI: 10.3389/fmicb.2016.01929] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/16/2016] [Indexed: 11/13/2022] Open
Abstract
In this study, we investigated the transcriptomic response of Streptococcus pneumoniae D39 to cysteine. Transcriptome comparison of the D39 wild-type grown at a restricted concentration of cysteine (0.03 mM) to one grown at a high concentration of cysteine (50 mM) in chemically-defined medium (CDM) revealed elevated expression of various genes/operons, i.e., spd-0150, metQ, spd-0431, metEF, gshT, spd-0618, fhs, tcyB, metB-csd, metA, spd-1898, yvdE, and cysK, likely to be involved in the transport and utilization of cysteine and/or methionine. Microarray-based data were further confirmed by quantitative RT-PCR. Promoter lacZ-fusion studies and quantitative RT-PCR data showed that the transcriptional regulator CmbR acts as a transcriptional repressor of spd-0150, metEF, gshT, spd-0618, tcyB, metA, and yvdE, putatively involved in cysteine uptake and utilization. The operator site of CmbR in the promoter regions of CmbR-regulated genes is predicted and confirmed by mutating or deleting CmbR operator sites from the promoter regions of these genes.
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Affiliation(s)
- Muhammad Afzal
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands; Department of Bioinformatics and Biotechnology, Government College UniversityFaisalabad, Pakistan
| | - Irfan Manzoor
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands; Department of Bioinformatics and Biotechnology, Government College UniversityFaisalabad, Pakistan
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen Groningen, Netherlands
| | - Sulman Shafeeq
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Stockholm, Sweden
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Wang Y, Hu B, Du S, Gao S, Chen X, Chen D. Proteomic Analyses Reveal the Mechanism of Dunaliella salina Ds-26-16 Gene Enhancing Salt Tolerance in Escherichia coli. PLoS One 2016; 11:e0153640. [PMID: 27135411 PMCID: PMC4852897 DOI: 10.1371/journal.pone.0153640] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/02/2016] [Indexed: 11/18/2022] Open
Abstract
We previously screened the novel gene Ds-26-16 from a 4 M salt-stressed Dunaliella salina cDNA library and discovered that this gene conferred salt tolerance to broad-spectrum organisms, including E. coli (Escherichia coli), Haematococcus pluvialis and tobacco. To determine the mechanism of this gene conferring salt tolerance, we studied the proteome of E. coli overexpressing the full-length cDNA of Ds-26-16 using the iTRAQ (isobaric tags for relative and absolute quantification) approach. A total of 1,610 proteins were identified, which comprised 39.4% of the whole proteome. Of the 559 differential proteins, 259 were up-regulated and 300 were down-regulated. GO (gene ontology) and KEGG (Kyoto encyclopedia of genes and genomes) enrichment analyses identified 202 major proteins, including those involved in amino acid and organic acid metabolism, energy metabolism, carbon metabolism, ROS (reactive oxygen species) scavenging, membrane proteins and ABC (ATP binding cassette) transporters, and peptidoglycan synthesis, as well as 5 up-regulated transcription factors. Our iTRAQ data suggest that Ds-26-16 up-regulates the transcription factors in E. coli to enhance salt resistance through osmotic balance, energy metabolism, and oxidative stress protection. Changes in the proteome were also observed in E. coli overexpressing the ORF (open reading frame) of Ds-26-16. Furthermore, pH, nitric oxide and glycerol content analyses indicated that Ds-26-16 overexpression increases nitric oxide content but has no effect on glycerol content, thus confirming that enhanced nitric oxide synthesis via lower intercellular pH was one of the mechanisms by which Ds-26-16 confers salt tolerance to E. coli.
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Affiliation(s)
- Yanlong Wang
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Bin Hu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Shipeng Du
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Shan Gao
- Department of Zoology and Developmental Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xiwen Chen
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Defu Chen
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
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Couvigny B, Thérial C, Gautier C, Renault P, Briandet R, Guédon E. Streptococcus thermophilus Biofilm Formation: A Remnant Trait of Ancestral Commensal Life? PLoS One 2015; 10:e0128099. [PMID: 26035177 PMCID: PMC4452758 DOI: 10.1371/journal.pone.0128099] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 04/23/2015] [Indexed: 12/27/2022] Open
Abstract
Microorganisms have a long history of use in food production and preservation. Their adaptation to food environments has profoundly modified their features, mainly through genomic flux. Streptococcus thermophilus, one of the most frequent starter culture organisms consumed daily by humans emerged recently from a commensal ancestor. As such, it is a useful model for genomic studies of bacterial domestication processes. Many streptococcal species form biofilms, a key feature of the major lifestyle of these bacteria in nature. However, few descriptions of S. thermophilus biofilms have been reported. An analysis of the ability of a representative collection of natural isolates to form biofilms revealed that S. thermophilus was a poor biofilm producer and that this characteristic was associated with an inability to attach firmly to surfaces. The identification of three biofilm-associated genes in the strain producing the most biofilms shed light on the reasons for the rarity of this trait in this species. These genes encode proteins involved in crucial stages of biofilm formation and are heterogeneously distributed between strains. One of the biofilm genes appears to have been acquired by horizontal transfer. The other two are located in loci presenting features of reductive evolution, and are absent from most of the strains analyzed. Their orthologs in commensal bacteria are involved in adhesion to host cells, suggesting that they are remnants of ancestral functions. The biofilm phenotype appears to be a commensal trait that has been lost during the genetic domestication of S. thermophilus, consistent with its adaptation to the milk environment and the selection of starter strains for dairy fermentations.
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Affiliation(s)
- Benoit Couvigny
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France
- AgroParisTech, UMR MICALIS, Jouy-en-Josas, France
| | - Claire Thérial
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France
- AgroParisTech, UMR MICALIS, Jouy-en-Josas, France
| | - Céline Gautier
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France
- AgroParisTech, UMR MICALIS, Jouy-en-Josas, France
| | - Pierre Renault
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France
- AgroParisTech, UMR MICALIS, Jouy-en-Josas, France
| | - Romain Briandet
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France
- AgroParisTech, UMR MICALIS, Jouy-en-Josas, France
| | - Eric Guédon
- INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France
- AgroParisTech, UMR MICALIS, Jouy-en-Josas, France
- * E-mail:
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16
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Sudhakar P, Reck M, Wang W, He FQ, Wagner-Döbler I, Dobler IW, Zeng AP. Construction and verification of the transcriptional regulatory response network of Streptococcus mutans upon treatment with the biofilm inhibitor carolacton. BMC Genomics 2014; 15:362. [PMID: 24884510 PMCID: PMC4048456 DOI: 10.1186/1471-2164-15-362] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 04/17/2014] [Indexed: 11/26/2022] Open
Abstract
Background Carolacton is a newly identified secondary metabolite causing altered cell morphology and death of Streptococcus mutans biofilm cells. To unravel key regulators mediating these effects, the transcriptional regulatory response network of S. mutans biofilms upon carolacton treatment was constructed and analyzed. A systems biological approach integrating time-resolved transcriptomic data, reverse engineering, transcription factor binding sites, and experimental validation was carried out. Results The co-expression response network constructed from transcriptomic data using the reverse engineering algorithm called the Trend Correlation method consisted of 8284 gene pairs. The regulatory response network inferred by superimposing transcription factor binding site information into the co-expression network comprised 329 putative transcriptional regulatory interactions and could be classified into 27 sub-networks each co-regulated by a transcription factor. These sub-networks were significantly enriched with genes sharing common functions. The regulatory response network displayed global hierarchy and network motifs as observed in model organisms. The sub-networks modulated by the pyrimidine biosynthesis regulator PyrR, the glutamine synthetase repressor GlnR, the cysteine metabolism regulator CysR, global regulators CcpA and CodY and the two component system response regulators VicR and MbrC among others could putatively be related to the physiological effect of carolacton. The predicted interactions from the regulatory network between MbrC, known to be involved in cell envelope stress response, and the murMN-SMU_718c genes encoding peptidoglycan biosynthetic enzymes were experimentally confirmed using Electro Mobility Shift Assays. Furthermore, gene deletion mutants of five predicted key regulators from the response networks were constructed and their sensitivities towards carolacton were investigated. Deletion of cysR, the node having the highest connectivity among the regulators chosen from the regulatory network, resulted in a mutant which was insensitive to carolacton thus demonstrating not only the essentiality of cysR for the response of S. mutans biofilms to carolacton but also the relevance of the predicted network. Conclusion The network approach used in this study revealed important regulators and interactions as part of the response mechanisms of S. mutans biofilm cells to carolacton. It also opens a door for further studies into novel drug targets against streptococci. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-362) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Irene W Dobler
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, 21073 Hamburg, Germany.
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Vergauwen B, Verstraete K, Senadheera DB, Dansercoer A, Cvitkovitch DG, Guédon E, Savvides SN. Molecular and structural basis of glutathione import in Gram-positive bacteria via GshT and the cystine ABC importer TcyBC of Streptococcus mutans. Mol Microbiol 2013; 89:288-303. [PMID: 23701283 DOI: 10.1111/mmi.12274] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2013] [Indexed: 12/25/2022]
Abstract
Glutathione (GSH) protects cells against oxidative injury and maintains a range of vital functions across all branches of life. Despite recent advances in our understanding of the transport mechanisms responsible for maintaining the spatiotemporal homeostasis of GSH and its conjugates in eukaryotes and Gram-negative bacteria, the molecular and structural basis of GSH import into Gram-positive bacteria has remained largely uncharacterized. Here, we employ genetic, biochemical and structural studies to investigate a possible glutathione import axis in Streptococcus mutans, an organism that has hitherto served as a model system. We show that GshT, a type 3 solute binding protein, displays physiologically relevant affinity for GSH and glutathione disulfide (GSSG). The crystal structure of GshT in complex with GSSG reveals a collapsed structure whereby the GS-I-leg of GSSG is accommodated tightly via extensive interactions contributed by the N- and C-terminal lobes of GshT, while the GS-II leg extends to the solvent. This can explain the ligand promiscuity of GshT in terms of binding glutathione analogues with substitutions at the cysteine-sulfur or the glycine-carboxylate. Finally, we show that GshT primes glutathione import via the L-cystine ABC transporter TcyBC, a membrane permease, which had previously exclusively been associated with the transport of L-cystine.
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Affiliation(s)
- Bjorn Vergauwen
- Unit for Structural Biology, Laboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE), Ghent University, K. L. Ledeganckstraat 35, B-9000, Ghent, Belgium.
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18
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Competence for natural genetic transformation in the Streptococcus bovis group streptococci S. infantarius and S. macedonicus. J Bacteriol 2013; 195:2612-20. [PMID: 23543718 DOI: 10.1128/jb.00230-13] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Natural genetic transformation is common among many species of the genus Streptococcus, but it has never, or rarely, been reported for the Streptococcus pyogenes and S. bovis groups of species, even though many streptococcal competence genes and the competence regulators SigX, ComR, and ComS are well conserved in both groups. To explore the incidence of competence in the S. bovis group, 25 isolates of S. infantarius and S. macedonicus were surveyed by employing culture in chemically defined media devoid of peptide nutrients and treatment with synthetic candidate pheromone peptides predicted from the sequence of the gene comS. Approximately half of strains examined were transformable, many transforming at high rates comparable to those for the well-characterized streptococcal natural transformation systems. In S. infantarius, nanomolar amounts of the synthetic pheromone LTAWWGL induced robust but transient competence in high-density cultures, but mutation of the ComRS locus abolished transformation. We conclude that at least these two species of the S. bovis group retain a robust system of natural transformation regulated by a ComRS pheromone circuit and the alternative sigma factor SigX and infer that transformation is even more common among the streptococci than has been recognized. The tools presented here will facilitate targeted genetic manipulation in this group of streptococci.
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19
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Streptococcus pneumoniae uses glutathione to defend against oxidative stress and metal ion toxicity. J Bacteriol 2012; 194:6248-54. [PMID: 22984260 DOI: 10.1128/jb.01393-12] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The thiol-containing tripeptide glutathione is an important cellular constituent of many eukaryotic and prokaryotic cells. In addition to its disulfide reductase activity, glutathione is known to protect cells from many forms of physiological stress. This report represents the first investigation into the role of glutathione in the Gram-positive pathogen Streptococcus pneumoniae. We demonstrate that pneumococci import extracellular glutathione using the ABC transporter substrate binding protein GshT. Mutation of gshT and the gene encoding glutathione reductase (gor) increases pneumococcal sensitivity to the superoxide generating compound paraquat, illustrating the importance of glutathione utilization in pneumococcal oxidative stress resistance. In addition, the gshT and gor mutant strains are hypersensitive to challenge with the divalent metal ions copper, cadmium, and zinc. The importance of glutathione utilization in pneumococcal colonization and invasion of the host is demonstrated by the attenuated phenotype of the gshT mutant strain in a mouse model of infection.
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20
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Computational analysis of cysteine and methionine metabolism and its regulation in dairy starter and related bacteria. J Bacteriol 2012; 194:3522-33. [PMID: 22522891 DOI: 10.1128/jb.06816-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sulfuric volatile compounds derived from cysteine and methionine provide many dairy products with a characteristic odor and taste. To better understand and control the environmental dependencies of sulfuric volatile compound formation by the dairy starter bacteria, we have used the available genome sequence and experimental information to systematically evaluate the presence of the key enzymes and to reconstruct the general modes of transcription regulation for the corresponding genes. The genomic organization of the key genes is suggestive of a subdivision of the reaction network into five modules, where we observed distinct differences in the modular composition between the families Lactobacillaceae, Enterococcaceae, and Leuconostocaceae, on the one hand, and the family Streptococcaceae, on the other. These differences are mirrored by the way in which transcription regulation of the genes is structured in these families. In the Lactobacillaceae, Enterococcaceae, and Leuconostocaceae, the main shared mode of transcription regulation is methionine (Met) T-box-mediated regulation. In addition, the gene metK, encoding S-adenosylmethionine (SAM) synthetase, is controlled via the S(MK) box (SAM). The S(MK) box is also found upstream of metK in species of the family Streptococcaceae. However, the transcription control of the other modules is mediated via three different LysR-family regulators, MetR/MtaR (methionine), CmbR (O-acetyl[homo]serine), and HomR (O-acetylhomoserine). Redefinition of the associated DNA-binding motifs helped to identify/disentangle the related regulons, which appeared to perfectly match the proposed subdivision of the reaction network.
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21
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Kim J, Senadheera DB, Lévesque CM, Cvitkovitch DG. TcyR regulates L-cystine uptake via the TcyABC transporter in Streptococcus mutans. FEMS Microbiol Lett 2012; 328:114-21. [PMID: 22212096 DOI: 10.1111/j.1574-6968.2011.02492.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 12/13/2011] [Accepted: 12/13/2011] [Indexed: 11/28/2022] Open
Abstract
Streptococcus mutans, a primary dental pathogen, has a remarkable capacity to scavenge nutrients from the oral biofilm for its survival. Cystine is an amino acid dimer formed by the oxidation of two cysteine residues that is required for optimal growth of S. mutans, which modulates l-cystine uptake via two recently identified transporters designated TcyABC and TcyDEFGH, which have not been fully characterized. Using a nonpolar tcyABC-deficient mutant (SmTcyABC), here, we report that l-cystine uptake is drastically diminished in the mutant, whereas its ability to grow is severely impaired under l-cystine starvation conditions, relative to wild type. A substrate competition assay showed that l-cystine uptake by the TcyABC transporter was strongly inhibited by dl-cystathionine and l-djenkolic acid and moderately inhibited by S-methyl-l-cysteine and l-cysteine. Using gene expression analysis, we observed that the tcyABC operon was upregulated under cystine starvation. TcyABC has been shown to be positively regulated by the LysR-type transcriptional regulator CysR. We identified another LysR-type transcriptional regulator that negatively regulates TcyABC with homology to the Bacillus subtilis YtlI regulator, which we termed TcyR. Our study enhances the understanding of l-cystine uptake in S. mutans, which allows survival and persistence of this pathogen in the oral biofilm.
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Affiliation(s)
- Jennifer Kim
- Dental Research Institute, University of Toronto, Toronto, ON, Canada
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Liu J, Wu C, Huang IH, Merritt J, Qi F. Differential response of Streptococcus mutans towards friend and foe in mixed-species cultures. MICROBIOLOGY-SGM 2011; 157:2433-2444. [PMID: 21565931 DOI: 10.1099/mic.0.048314-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In the oral biofilm, the 'mitis' streptococci are among the first group of organisms to colonize the tooth surface. Their proliferation is thought to be an important factor required for antagonizing the growth of cariogenic species such as Streptococcus mutans. In this study, we used a three-species mixed culture to demonstrate that another ubiquitous early colonizing species, Veillonella parvula, can greatly affect the outcome of the competition between a pair of antagonists such as S. mutans and Streptococcus gordonii. Transcriptome analysis further revealed that S. mutans responds differentially to its friend (V. parvula) and foe (S. gordonii). In the mixed culture with S. gordonii, all but one of the S. mutans sugar uptake and metabolic genes were downregulated, while genes for alternative energy source utilization and H₂O₂ tolerance were upregulated, resulting in a slower but persistent growth. In contrast, when cultured with V. parvula, S. mutans grew equally well or better than in monoculture and exhibited relatively few changes within its transcriptome. When V. parvula was introduced into the mixed culture of S. mutans and S. gordonii, it rescued the growth inhibition of S. mutans. In this three-species environment, S. mutans increased the expression of genes required for the uptake and metabolism of minor sugars, while genes required for oxidative stress tolerance were downregulated. We conclude that the major factors that affect the competition between S. mutans and S. gordonii are carbohydrate utilization and H₂O₂ resistance. The presence of V. parvula in the tri-species culture mitigates these two major factors and allows S. mutans to proliferate, despite the presence of S. gordonii.
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Affiliation(s)
- Jinman Liu
- College of Dentistry, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Chenggang Wu
- College of Dentistry, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - I-Hsiu Huang
- College of Dentistry, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Justin Merritt
- College of Dentistry, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Fengxia Qi
- College of Dentistry, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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André G, Haudecoeur E, Monot M, Ohtani K, Shimizu T, Dupuy B, Martin-Verstraete I. Global regulation of gene expression in response to cysteine availability in Clostridium perfringens. BMC Microbiol 2010; 10:234. [PMID: 20822510 PMCID: PMC2940859 DOI: 10.1186/1471-2180-10-234] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 09/07/2010] [Indexed: 11/24/2022] Open
Abstract
Background Cysteine has a crucial role in cellular physiology and its synthesis is tightly controlled due to its reactivity. However, little is known about the sulfur metabolism and its regulation in clostridia compared with other firmicutes. In Clostridium perfringens, the two-component system, VirR/VirS, controls the expression of the ubiG operon involved in methionine to cysteine conversion in addition to the expression of several toxin genes. The existence of links between the C. perfringens virulence regulon and sulfur metabolism prompted us to analyze this metabolism in more detail. Results We first performed a tentative reconstruction of sulfur metabolism in C. perfringens and correlated these data with the growth of strain 13 in the presence of various sulfur sources. Surprisingly, C. perfringens can convert cysteine to methionine by an atypical still uncharacterized pathway. We further compared the expression profiles of strain 13 after growth in the presence of cystine or homocysteine that corresponds to conditions of cysteine depletion. Among the 177 genes differentially expressed, we found genes involved in sulfur metabolism and controlled by premature termination of transcription via a cysteine specific T-box system (cysK-cysE, cysP1 and cysP2) or an S-box riboswitch (metK and metT). We also showed that the ubiG operon was submitted to a triple regulation by cysteine availability via a T-box system, by the VirR/VirS system via the VR-RNA and by the VirX regulatory RNA. In addition, we found that expression of pfoA (theta-toxin), nagL (one of the five genes encoding hyaluronidases) and genes involved in the maintenance of cell redox status was differentially expressed in response to cysteine availability. Finally, we showed that the expression of genes involved in [Fe-S] clusters biogenesis and of the ldh gene encoding the lactate dehydrogenase was induced during cysteine limitation. Conclusion Several key functions for the cellular physiology of this anaerobic bacterium were controlled in response to cysteine availability. While most of the genes involved in sulfur metabolism are regulated by premature termination of transcription, other still uncharacterized mechanisms of regulation participated in the induction of gene expression during cysteine starvation.
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Affiliation(s)
- Gaelle André
- Institut Pasteur, Unité de Génétique des Génomes Bactériens and Unité des Bactéries Anaérobies et Toxines, 28 rue du Docteur Roux, 75015 Paris, France
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