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Merritt J, Kreth J. Illuminating the oral microbiome and its host interactions: tools and approaches for molecular microbiology studies. FEMS Microbiol Rev 2023; 47:fuac050. [PMID: 36549660 PMCID: PMC10719069 DOI: 10.1093/femsre/fuac050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Advancements in DNA sequencing technologies within the last decade have stimulated an unprecedented interest in the human microbiome, largely due the broad diversity of human diseases found to correlate with microbiome dysbiosis. As a direct consequence of these studies, a vast number of understudied and uncharacterized microbes have been identified as potential drivers of mucosal health and disease. The looming challenge in the field is to transition these observations into defined molecular mechanistic studies of symbiosis and dysbiosis. In order to meet this challenge, many of these newly identified microbes will need to be adapted for use in experimental models. Consequently, this review presents a comprehensive overview of the molecular microbiology tools and techniques that have played crucial roles in genetic studies of the bacteria found within the human oral microbiota. Here, we will use specific examples from the oral microbiome literature to illustrate the biology supporting these techniques, why they are needed in the field, and how such technologies have been implemented. It is hoped that this information can serve as a useful reference guide to help catalyze molecular microbiology studies of the many new understudied and uncharacterized species identified at different mucosal sites in the body.
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Affiliation(s)
- Justin Merritt
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, United States
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, United States
| | - Jens Kreth
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, United States
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, United States
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2
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Akbari MS, Doran KS, Burcham LR. Metal Homeostasis in Pathogenic Streptococci. Microorganisms 2022; 10:microorganisms10081501. [PMID: 35893559 PMCID: PMC9331361 DOI: 10.3390/microorganisms10081501] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 02/05/2023] Open
Abstract
Streptococcus spp. are an important genus of Gram-positive bacteria, many of which are opportunistic pathogens that are capable of causing invasive disease in a wide range of populations. Metals, especially transition metal ions, are an essential nutrient for all organisms. Therefore, to survive across dynamic host environments, Streptococci have evolved complex systems to withstand metal stress and maintain metal homeostasis, especially during colonization and infection. There are many different types of transport systems that are used by bacteria to import or export metals that can be highly specific or promiscuous. Focusing on the most well studied transition metals of zinc, manganese, iron, nickel, and copper, this review aims to summarize the current knowledge of metal homeostasis in pathogenic Streptococci, and their role in virulence.
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3
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Pan Y, Chen Y, Chen J, Ma Q, Gong T, Yu S, Zhang Q, Zou J, Li Y. The Adc regulon mediates zinc homeostasis in Streptococcus mutans. Mol Oral Microbiol 2021; 36:278-290. [PMID: 34351080 DOI: 10.1111/omi.12350] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 02/05/2023]
Abstract
Zinc (Zn2+ ) is an essential divalent trace metal for living cells. Intracellular zinc homeostasis is critical to the survival and virulence of bacteria. Thus, the frequent fluctuations of salivary zinc, caused by the low physiological level and the frequent exogenous zinc introduction, present a serious challenge for bacteria colonizing the oral cavity. However, the regulation strategies to keep intracellular Zn2+ homeostasis in Streptococcus mutans, an important causative pathogen of dental caries, are unknown. Because zinc uptake is primarily mediated by an ATP-binding ABC transporter AdcABC in Streptococcus strains, we examined the function of AdcABC and transcription factor AdcR in S. mutans in this study. The results demonstrated that deletion of either adcA or adcCB gene impaired the growth but enhanced the extracellular polymeric matrix production in S. mutans, both of which could be relieved after excessive Zn2+ supplementation. Using RNA sequencing analysis, quantitative reverse transcription polymerase chain reaction examination, LacZ-reporter studies, and electrophoretic mobility shift assay, we showed that a MarR (multiple antibiotic resistance regulator) family transcription factor, AdcR, negatively regulates the expression of the genes adcR, adcC, adcB, and adcA by acting on the adcRCB and adcA promoters in response to Zn2+ concentration in their environmental niches. The deletion of adcR increases the sensitivity of S. mutans to excessive Zn2+ supply. Taken together, our findings suggest that Adc regulon, which consists of a Zn2+ uptake transporter AdcCBA and a Zn2+ -responsive repressor AdcR, plays a prominent role in the maintenance of intracellular zinc homeostasis of S. mutans.
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Affiliation(s)
- Yangyang Pan
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yang Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jiamin Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qizhao Ma
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Tao Gong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Shuxing Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qiong Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Zou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuqing Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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4
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Ganguly T, Peterson AM, Kajfasz JK, Abranches J, Lemos JA. Zinc import mediated by AdcABC is critical for colonization of the dental biofilm by Streptococcus mutans in an animal model. Mol Oral Microbiol 2021; 36:214-224. [PMID: 33819383 PMCID: PMC9178666 DOI: 10.1111/omi.12337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/29/2021] [Accepted: 04/01/2021] [Indexed: 12/18/2022]
Abstract
Trace metals are essential to all domains of life but toxic when found at high concentrations. Although the importance of iron in host-pathogen interactions is firmly established, contemporary studies indicate that other trace metals, including manganese and zinc, are also critical to the infectious process. In this study, we sought to identify and characterize the zinc uptake system(s) of Streptococcus mutans, a keystone pathogen in dental caries and a causative agent of bacterial endocarditis. Different than other pathogenic bacteria, including several streptococci, that encode multiple zinc import systems, bioinformatic analysis indicated that the S. mutans core genome encodes a single, highly conserved, zinc importer commonly known as AdcABC. Inactivation of the genes coding for the metal-binding AdcA (ΔadcA) or both AdcC ATPase and AdcB permease (ΔadcCB) severely impaired the ability of S. mutans to grow under zinc-depleted conditions. Intracellular metal quantifications revealed that both mutants accumulated less zinc when grown in the presence of a subinhibitory concentration of a zinc-specific chelator. Notably, the ΔadcCB strain displayed a severe colonization defect in a rat oral infection model. Both Δadc strains were hypersensitive to high concentrations of manganese, showed reduced peroxide tolerance, and formed less biofilm in sucrose-containing media when cultivated in the presence of the lowest amount of zinc that support their growth, but not when zinc was supplied in excess. Collectively, this study identifies AdcABC as the major high affinity zinc importer of S. mutans and provides preliminary evidence that zinc is a growth-limiting factor within the dental biofilm.
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Affiliation(s)
- Tridib Ganguly
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
| | - Alexandra M. Peterson
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
| | - Jessica K. Kajfasz
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
| | - Jacqueline Abranches
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
| | - José A. Lemos
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
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5
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Bosma EF, Rau MH, van Gijtenbeek LA, Siedler S. Regulation and distinct physiological roles of manganese in bacteria. FEMS Microbiol Rev 2021; 45:6284802. [PMID: 34037759 PMCID: PMC8632737 DOI: 10.1093/femsre/fuab028] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/21/2021] [Indexed: 02/06/2023] Open
Abstract
Manganese (Mn2+) is an essential trace element within organisms spanning the entire tree of life. In this review, we provide an overview of Mn2+ transport and the regulation of its homeostasis in bacteria, with a focus on its functions beyond being a cofactor for enzymes. Crucial differences in Mn2+ homeostasis exist between bacterial species that can be characterized to have an iron- or manganese-centric metabolism. Highly iron-centric species require minimal Mn2+ and mostly use it as a mechanism to cope with oxidative stress. As a consequence, tight regulation of Mn2+ uptake is required, while organisms that use both Fe2+ and Mn2+ need other layers of regulation for maintaining homeostasis. We will focus in detail on manganese-centric bacterial species, in particular lactobacilli, that require little to no Fe2+ and use Mn2+ for a wider variety of functions. These organisms can accumulate extraordinarily high amounts of Mn2+ intracellularly, enabling the nonenzymatic use of Mn2+ for decomposition of reactive oxygen species while simultaneously functioning as a mechanism of competitive exclusion. We further discuss how Mn2+ accumulation can provide both beneficial and pathogenic bacteria with advantages in thriving in their niches.
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Affiliation(s)
- Elleke F Bosma
- Chr. Hansen A/S, Discovery, R&D, 2970 Hoersholm, Denmark
| | - Martin H Rau
- Chr. Hansen A/S, Discovery, R&D, 2970 Hoersholm, Denmark
| | | | - Solvej Siedler
- Corresponding author: Boege Allé 10-12, 2970 Hoersholm, Denmark. Tel: +45 52 18 08 25; E-mail:
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6
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Martini AM, Moricz BS, Ripperger AK, Tran PM, Sharp ME, Forsythe AN, Kulhankova K, Salgado-Pabón W, Jones BD. Association of Novel Streptococcus sanguinis Virulence Factors With Pathogenesis in a Native Valve Infective Endocarditis Model. Front Microbiol 2020; 11:10. [PMID: 32082276 PMCID: PMC7005726 DOI: 10.3389/fmicb.2020.00010] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 01/06/2020] [Indexed: 12/11/2022] Open
Abstract
Streptococcus sanguinis (S. sanguinis) is an abundant oral commensal which can cause disseminated human infection if it gains access to the bloodstream. The most important among these diseases is infective endocarditis (IE). While virulence phenotypes of S. sanguinis have been correlated to disease severity, genetic factors mediating these phenotypes, and contributing to pathogenesis are largely uncharacterized. In this report, we investigate the roles of 128 genes in virulence-related phenotypes of S. sanguinis and characterize the pathogenic potential of two selected mutants in a left-sided, native valve IE rabbit model. Assays determining the ability of our mutant strains to produce a biofilm, bind to and aggregate platelets, and adhere to or invade endothelial cells identified sixteen genes with novel association to these phenotypes. These results suggest the presence of many uncharacterized genes involved in IE pathogenesis which may be relevant for disease progression. Two mutants identified by the above screening process – SSA_1099, encoding an RTX-like protein, and mur2, encoding a peptidoglycan hydrolase – were subsequently evaluated in vivo. Wild type (WT) S. sanguinis reliably induced cardiac vegetations, while the SSA_1099 and mur2 mutants produced either no vegetation or vegetations of small size. Splenomegaly was reduced in both mutant strains compared to WT, while pathology of other distal organs was indistinguishable. Histopathology analyses suggest the cardiac lesions and vegetations in this model resemble those observed in humans. These data indicate that SSA_1099 and mur2 encode virulence factors in S. sanguinis which are integral to pathogenesis of IE.
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Affiliation(s)
- Anthony M Martini
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Bridget S Moricz
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Allison K Ripperger
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Phuong M Tran
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Molly E Sharp
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Ana N Forsythe
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Katarina Kulhankova
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Wilmara Salgado-Pabón
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Bradley D Jones
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States.,Graduate Program in Genetics, The University of Iowa, Iowa City, IA, United States
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7
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Intensive targeting of regulatory competence genes by transposable elements in streptococci. Mol Genet Genomics 2018; 294:531-548. [DOI: 10.1007/s00438-018-1507-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/21/2018] [Indexed: 10/27/2022]
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8
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Capdevila DA, Huerta F, Edmonds KA, Le MT, Wu H, Giedroc DP. Tuning site-specific dynamics to drive allosteric activation in a pneumococcal zinc uptake regulator. eLife 2018; 7:37268. [PMID: 30328810 PMCID: PMC6224198 DOI: 10.7554/elife.37268] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 10/16/2018] [Indexed: 11/25/2022] Open
Abstract
MarR (multiple antibiotic resistance repressor) family proteins are bacterial repressors that regulate transcription in response to a wide range of chemical signals. Although specific features of MarR family function have been described, the role of atomic motions in MarRs remains unexplored thus limiting insights into the evolution of allostery in this ubiquitous family of repressors. Here, we provide the first experimental evidence that internal dynamics play a crucial functional role in MarR proteins. Streptococcus pneumoniae AdcR (adhesin-competence repressor) regulates ZnII homeostasis and ZnII functions as an allosteric activator of DNA binding. ZnII coordination triggers a transition from somewhat independent domains to a more compact structure. We identify residues that impact allosteric activation on the basis of ZnII-induced perturbations of atomic motions over a wide range of timescales. These findings appear to reconcile the distinct allosteric mechanisms proposed for other MarRs and highlight the importance of conformational dynamics in biological regulation.
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Affiliation(s)
| | - Fidel Huerta
- Department of Chemistry, Indiana University, Bloomington, United States.,Graduate Program in Biochemistry, Indiana University, Bloomington, United States
| | | | - My Tra Le
- Department of Chemistry, Indiana University, Bloomington, United States
| | - Hongwei Wu
- Department of Chemistry, Indiana University, Bloomington, United States
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, United States.,Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, United States
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9
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Zheng Y, Li Y, Long H, Zhao X, Jia K, Li J, Wang L, Wang R, Lu X, Zhang D. bifA Regulates Biofilm Development of Pseudomonas putida MnB1 as a Primary Response to H 2O 2 and Mn 2. Front Microbiol 2018; 9:1490. [PMID: 30042743 PMCID: PMC6048274 DOI: 10.3389/fmicb.2018.01490] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 06/15/2018] [Indexed: 12/15/2022] Open
Abstract
Pseudomonas putida (P. putida) MnB1 is a widely used model strain in environment science and technology for determining microbial manganese oxidation. Numerous studies have demonstrated that the growth and metabolism of P. putida MnB1 are influenced by various environmental factors. In this study, we investigated the effects of hydrogen peroxide (H2O2) and manganese (Mn2+) on proliferation, Mn2+ acquisition, anti-oxidative system, and biofilm formation of P. putida MnB1. The related orthologs of 4 genes, mco, mntABC, sod, and bifA, were amplified from P. putida GB1 and their involvement were assayed, respectively. We found that P. putida MnB1 degraded H2O2, and quickly recovered for proliferation, but its intracellular oxidative stress state was maintained, with rapid biofilm formation after H2O2 depletion. The data from mco, mntABC, sod and bifA expression levels by qRT-PCR, elucidated a sensitivity toward bifA-mediated biofilm formation, in contrary to intracellular anti-oxidative system under H2O2 exposure. Meanwhile, Mn2+ ion supply inhibited biofilm formation of P. putida MnB1. The expression pattern of these genes showed that Mn2+ ion supply likely functioned to modulate biofilm formation rather than only acting as nutrient substrate for P. putida MnB1. Furthermore, blockade of BifA activity by GTP increased the formation and development of biofilms during H2O2 exposure, while converse response to Mn2+ ion supply was evident. These distinct cellular responses to H2O2 and Mn2+ provide insights on the common mechanism by which environmental microorganisms may be protected from exogenous factors. We postulate that BifA-mediated biofilm formation but not intracellular anti-oxidative system may be a primary protective strategy adopted by P. putida MnB1. These findings will highlight the understanding of microbial adaptation mechanisms to distinct environmental stresses.
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Affiliation(s)
- Yanjing Zheng
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Yumei Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Hongyan Long
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Xiaojuan Zhao
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Keke Jia
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Juan Li
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
| | - Leyong Wang
- Key Laboratory of Mesoscopic Chemistry of MOE and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing, China
| | - Ruiyong Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Xiancai Lu
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
| | - Dongmei Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
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10
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Le Breton Y, Belew AT, Freiberg JA, Sundar GS, Islam E, Lieberman J, Shirtliff ME, Tettelin H, El-Sayed NM, McIver KS. Genome-wide discovery of novel M1T1 group A streptococcal determinants important for fitness and virulence during soft-tissue infection. PLoS Pathog 2017; 13:e1006584. [PMID: 28832676 PMCID: PMC5584981 DOI: 10.1371/journal.ppat.1006584] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/05/2017] [Accepted: 08/15/2017] [Indexed: 01/08/2023] Open
Abstract
The Group A Streptococcus remains a significant human pathogen causing a wide array of disease ranging from self-limiting to life-threatening invasive infections. Epithelium (skin or throat) colonization with progression to the subepithelial tissues is the common step in all GAS infections. Here, we used transposon-sequencing (Tn-seq) to define the GAS 5448 genetic requirements for in vivo fitness in subepithelial tissue. A near-saturation transposon library of the M1T1 GAS 5448 strain was injected subcutaneously into mice, producing suppurative inflammation at 24 h that progressed to prominent abscesses with tissue necrosis at 48 h. The library composition was monitored en masse by Tn-seq and ratios of mutant abundance comparing the output (12, 24 and 48 h) versus input (T0) mutant pools were calculated for each gene. We identified a total of 273 subcutaneous fitness (scf) genes with 147 genes (55 of unknown function) critical for the M1T1 GAS 5448 fitness in vivo; and 126 genes (53 of unknown function) potentially linked to in vivo fitness advantage. Selected scf genes were validated in competitive subcutaneous infection with parental 5448. Two uncharacterized genes, scfA and scfB, encoding putative membrane-associated proteins and conserved among Gram-positive pathogens, were further characterized. Defined scfAB mutants in GAS were outcompeted by wild type 5448 in vivo, attenuated for lesion formation in the soft tissue infection model and dissemination to the bloodstream. We hypothesize that scfAB play an integral role in enhancing adaptation and fitness of GAS during localized skin infection, and potentially in propagation to other deeper host environments. The WHO ranks the Group A Streptococcus (GAS) in the top 10 leading causes of morbidity and mortality from infectious diseases worldwide. GAS is a strict human pathogen causing both benign superficial infections as well as life-threatening invasive diseases. All GAS infections begin by colonization of an epithelium (throat or skin) followed by propagation into subepithelial tissues. The genetic requirements for M1T1 GAS 5448 within this niche were interrogated by in vivo transposon sequencing (Tn-seq), identifying 273 subcutaneous fitness (scf) genes with 108 of those previously of “unknown function”. Two yet uncharacterized genes, scfA and scfB, were shown to be critical during GAS 5448 soft tissue infection and dissemination into the bloodstream. Thus, this study improves the functional annotation of the GAS genome, providing new insights into GAS pathophysiology and enhancing the development of novel GAS therapeutics.
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Affiliation(s)
- Yoann Le Breton
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, United States of America
- * E-mail: (YLB); (KSM)
| | - Ashton T. Belew
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, United States of America
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, Maryland, United States of America
| | - Jeffrey A. Freiberg
- Graduate Program in Life Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Ganesh S. Sundar
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, United States of America
| | - Emrul Islam
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, United States of America
| | - Joshua Lieberman
- Division of Infectious Diseases, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Mark E. Shirtliff
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbial Pathogenesis, Dental School, University of Maryland, Baltimore, Maryland, United States of America
| | - Hervé Tettelin
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Najib M. El-Sayed
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, United States of America
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, Maryland, United States of America
| | - Kevin S. McIver
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, United States of America
- * E-mail: (YLB); (KSM)
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11
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Chen J, Li T, Zhou X, Cheng L, Huo Y, Zou J, Li Y. Characterization of the clustered regularly interspaced short palindromic repeats sites in Streptococcus mutans isolated from early childhood caries patients. Arch Oral Biol 2017; 83:174-180. [PMID: 28783550 DOI: 10.1016/j.archoralbio.2017.07.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/27/2017] [Accepted: 07/27/2017] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The aim of this study was to analyze the characteristics of the clustered regularly interspaced short palindromic repeats (CRISPR) sites in 45 clinical Streptococcus mutans strains and their relationship to the clinical manifestations of early childhood caries (ECC). METHODS Forty-five S. mutans strains were isolated from the plaque samples taken from sixty-three children. CRISPR sites were sequenced and BLAST was used to compare these sites to those in the CRISPRTarget database. The association between the distribution of CRISPR sites and the manifestation of caries was analyzed by Chi-Square test. Further, biofilm formation (by crystal violet staining) and the synthesis of polysaccharide (by anthrone-sulfuric method) of all clinical isolated S. mutans strains with both CRISPR sites and no CRISPR site were comapared. Finally, acidogenicity and acidurity of two typical strains were determined using pH drop and acid tolerance assays. Biofilm formation and EPS synthesis by two typical strains were compared by 3D CLSM (Confocal Laser Scanning Microscope) assays and the expression of gtf genes were evaluated using qPCR. RESULTS We found that most of the spacers in the clinical S. mutans strains were derived from Streptococcus phages APCM01 and M102. The number of CRISPR sites in these strains was associated with the clinical manifestations of ECC. Moreover, we found that the biofilm formation and EPS synthesis ability of the S. mutans strains with both CRISPR sites was significant improved. CONCLUSIONS An association was found between the distribution of CRISPR sites and the clinical manifestations of caries. The CRISPR sites might contribute to the cariogenic potential of S. mutans.
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Affiliation(s)
- Jing Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Tiancheng Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Lei Cheng
- Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuanyuan Huo
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Zou
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuqing Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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The Adc/Lmb System Mediates Zinc Acquisition in Streptococcus agalactiae and Contributes to Bacterial Growth and Survival. J Bacteriol 2016; 198:3265-3277. [PMID: 27672194 DOI: 10.1128/jb.00614-16] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/16/2016] [Indexed: 12/14/2022] Open
Abstract
The Lmb protein of Streptococcus agalactiae is described as an adhesin that binds laminin, a component of the human extracellular matrix. In this study, we revealed a new role for this protein in zinc uptake. We also identified two Lmb homologs, AdcA and AdcAII, redundant binding proteins that combine with the AdcCB translocon to form a zinc-ABC transporter. Expression of this transporter is controlled by the zinc concentration in the medium through the zinc-dependent regulator AdcR. Triple deletion of lmb, adcA, and adcAII, or that of the adcCB genes, impaired growth and cell separation in a zinc-restricted environment. Moreover, we found that this Adc zinc-ABC transporter promotes S. agalactiae growth and survival in some human biological fluids, suggesting that it contributes to the infection process. These results indicated that zinc has biologically vital functions in S. agalactiae and that, under the conditions tested, the Adc/Lmb transporter constitutes the main zinc acquisition system of the bacterium. IMPORTANCE A zinc transporter, composed of three redundant binding proteins (Lmb, AdcA, and AdcAII), was characterized in Streptococcus agalactiae This system was shown to be essential for bacterial growth and morphology in zinc-restricted environments, including human biological fluids.
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Abstract
Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.
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Fléchard M, Gilot P. Physiological impact of transposable elements encoding DDE transposases in the environmental adaptation of Streptococcus agalactiae. Microbiology (Reading) 2014; 160:1298-1315. [DOI: 10.1099/mic.0.077628-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We have referenced and described Streptococcus agalactiae transposable elements encoding DDE transposases. These elements belonged to nine families of insertion sequences (ISs) and to a family of conjugative transposons (TnGBSs). An overview of the physiological impact of the insertion of all these elements is provided. DDE-transposable elements affect S. agalactiae in a number of aspects of its capability to adapt to various environments and modulate the expression of several virulence genes, the scpB–lmB genomic region and the genes involved in capsule expression and haemolysin transport being the targets of several different mobile elements. The referenced mobile elements modify S. agalactiae behaviour by transferring new gene(s) to its genome, by modifying the expression of neighbouring genes at the integration site or by promoting genomic rearrangements. Transposition of some of these elements occurs in vivo, suggesting that by dynamically regulating some adaptation and/or virulence genes, they improve the ability of S. agalactiae to reach different niches within its host and ensure the ‘success’ of the infectious process.
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Affiliation(s)
- Maud Fléchard
- Biochimie et Génétique Moléculaire Bactérienne, Institut des Sciences de la Vie, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Philippe Gilot
- INRA, UMR1282 Infectiologie et Santé Publique, F-37380 Nouzilly, France
- Université de Tours, UMR1282 Infectiologie et Santé Publique, Bactéries et Risque Materno-Foetal, F-37032 Tours, France
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15
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Lin CSH, Chao SY, Hammel M, Nix JC, Tseng HL, Tsou CC, Fei CH, Chiou HS, Jeng US, Lin YS, Chuang WJ, Wu JJ, Wang S. Distinct structural features of the peroxide response regulator from group A Streptococcus drive DNA binding. PLoS One 2014; 9:e89027. [PMID: 24586487 PMCID: PMC3931707 DOI: 10.1371/journal.pone.0089027] [Citation(s) in RCA: 13] [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: 07/15/2013] [Accepted: 01/19/2014] [Indexed: 11/23/2022] Open
Abstract
Group A streptococcus (GAS, Streptococcus pyogenes) is a strict human pathogen that causes severe, invasive diseases. GAS does not produce catalase, but has an ability to resist killing by reactive oxygen species (ROS) through novel mechanisms. The peroxide response regulator (PerR), a member of ferric uptake regulator (Fur) family, plays a key role for GAS to cope with oxidative stress by regulating the expression of multiple genes. Our previous studies have found that expression of an iron-binding protein, Dpr, is under the direct control of PerR. To elucidate the molecular interactions of PerR with its cognate promoter, we have carried out structural studies on PerR and PerR-DNA complex. By combining crystallography and small-angle X-ray scattering (SAXS), we confirmed that the determined PerR crystal structure reflects its conformation in solution. Through mutagenesis and biochemical analysis, we have identified DNA-binding residues suggesting that PerR binds to the dpr promoter at the per box through a winged-helix motif. Furthermore, we have performed SAXS analysis and resolved the molecular architecture of PerR-DNA complex, in which two 30 bp DNA fragments wrap around two PerR homodimers by interacting with the adjacent positively-charged winged-helix motifs. Overall, we provide structural insights into molecular recognition of DNA by PerR and define the hollow structural arrangement of PerR-30bpDNA complex, which displays a unique topology distinct from currently proposed DNA-binding models for Fur family regulators.
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Affiliation(s)
- Chang Sheng-Huei Lin
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shi-Yu Chao
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Michal Hammel
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Jay C. Nix
- Molecular Biology Consortium, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Hsiao-Ling Tseng
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Chih-Cheng Tsou
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Chun-Hsien Fei
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Huo-Sheng Chiou
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - U-Ser Jeng
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Yee-Shin Lin
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Woei-Jer Chuang
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jiunn-Jong Wu
- Molecular Biology Consortium, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shuying Wang
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
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16
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Wan C, Zhang P, Lee DJ, Yang X, Liu X, Sun S, Pan X. Disintegration of aerobic granules: role of second messenger cyclic di-GMP. BIORESOURCE TECHNOLOGY 2013; 146:330-335. [PMID: 23948271 DOI: 10.1016/j.biortech.2013.07.073] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 07/14/2013] [Accepted: 07/17/2013] [Indexed: 06/02/2023]
Abstract
Loss of structural stability of aerobic granular process is the challenge for its field applications to treat wastewaters. The second messenger, cyclic diguanylate (c-di-GMP), is widely used by bacteria to regulate the synthesis of exopolysaccharide. This study for the first time confirmed the correlation between concentration of intracellular c-di-GMP and the granular stability under sequencing batch reactor (MBR) mode. In the presence of manganese ions (Mn(2+)), the concentrations of intracellular c-di-GMP and of extracellular polysaccharides and proteins in granules were declined. Clone library study revealed that the polysaccharide producers. Acinetobacter sp., Thauera sp., Bdellovibrio sp. and Paracoccus sp. were lost after Mn(2+) addition. The findings reported herein confirmed that the c-di-GMP is a key chemical factor epistatic to quorum sensing to determine granular stability. Stimulation of synthesis of intracellular c-di-GMP presents a potential way to enhance long-term stability of aerobic granules.
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Affiliation(s)
- Chunli Wan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Peng Zhang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Duu-Jong Lee
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China; Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan; Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
| | - Xue Yang
- Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China
| | - Xiang Liu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Supu Sun
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Xiangliang Pan
- Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China
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17
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Shafeeq S, Kuipers OP, Kloosterman TG. The role of zinc in the interplay between pathogenic streptococci and their hosts. Mol Microbiol 2013; 88:1047-57. [DOI: 10.1111/mmi.12256] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2013] [Indexed: 12/26/2022]
Affiliation(s)
- Sulman Shafeeq
- Department of Molecular Genetics; Groningen Biomolecular Sciences and Biotechnology Institute; University of Groningen; Nijenborgh 7; 9747 AG; Groningen; the Netherlands
| | - Oscar P. Kuipers
- Department of Molecular Genetics; Groningen Biomolecular Sciences and Biotechnology Institute; University of Groningen; Nijenborgh 7; 9747 AG; Groningen; the Netherlands
| | - Tomas G. Kloosterman
- Department of Molecular Genetics; Groningen Biomolecular Sciences and Biotechnology Institute; University of Groningen; Nijenborgh 7; 9747 AG; Groningen; the Netherlands
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McDowell EJ, Callegari EA, Malke H, Chaussee MS. CodY-mediated regulation of Streptococcus pyogenes exoproteins. BMC Microbiol 2012; 12:114. [PMID: 22721528 PMCID: PMC3438106 DOI: 10.1186/1471-2180-12-114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 05/23/2012] [Indexed: 11/19/2022] Open
Abstract
Background The production of Streptococcus pyogenes exoproteins, many of which contribute to virulence, is regulated in response to nutrient availability. CodY is a transcriptional regulator that controls gene expression in response to amino acid availability. The purpose of this study was to identify differences in the expression of streptococcal exoproteins associated with deletion of the codY gene. Results We compared the secreted proteins produced by wild-type S. pyogenes to a codY mutant in the post-exponential phase of growth. We used both one and two-dimensional gel electrophoresis to separate exoproteins. Proteins that were significantly different in abundance upon repeated analysis were identified with tandem mass spectrometry. The production of the secreted cysteine protease SpeB, a secreted chromosomally encoded nuclease (SdaB), and a putative adhesion factor (Spy49_0549) were more abundant in supernatant fluids obtained from the codY mutant. In addition, hyaluronidase (HylA), CAMP factor (Cfa), a prophage encoded nuclease (Spd-3), and an uncharacterized extracellular protein (Spy49_0015) were less abundant in supernatant fluids obtained from the codY mutant strain. Enzymatic assays showed greater DNase activity in culture supernatants isolated in the post-exponential phase of growth from the codY mutant strain compared to the wild-type strain. Because extracellular nucleases and proteases can influence biofilm formation, we also measured the ability of the strains to form biofilms during growth with both rich medium (Todd Hewitt yeast extract; THY) and chemically defined media (CDM). No difference was observed with rich media but with CDM the biofilms formed by the codY mutant strain had less biomass compared to the wild-type strain. Conclusions Overall, the results indicate that CodY alters the abundance of a select group of S. pyogenes exoproteins, including DNases, a protease, and hylauronidase, which together may alleviate starvation by promoting dissemination of the pathogen to nutrient rich environments and by hydrolysis of host macromolecules.
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Affiliation(s)
- Emily J McDowell
- Division of Basic Biomedical Sciences, The Sanford School of Medicine of the University of South Dakota, Vermillion, SD, USA
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Geng J, Chiu CH, Tang P, Chen Y, Shieh HR, Hu S, Chen YYM. Complete genome and transcriptomes of Streptococcus parasanguinis FW213: phylogenic relations and potential virulence mechanisms. PLoS One 2012; 7:e34769. [PMID: 22529932 PMCID: PMC3329508 DOI: 10.1371/journal.pone.0034769] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 03/05/2012] [Indexed: 01/13/2023] Open
Abstract
Streptococcus parasanguinis, a primary colonizer of the tooth surface, is also an opportunistic pathogen for subacute endocarditis. The complete genome of strain FW213 was determined using the traditional shotgun sequencing approach and further refined by the transcriptomes of cells in early exponential and early stationary growth phases in this study. The transcriptomes also discovered 10 transcripts encoding known hypothetical proteins, one pseudogene, five transcripts matched to the Rfam and additional 87 putative small RNAs within the intergenic regions defined by the GLIMMER analysis. The genome contains five acquired genomic islands (GIs) encoding proteins which potentially contribute to the overall pathogenic capacity and fitness of this microbe. The differential expression of the GIs and various open reading frames outside the GIs at the two growth phases suggested that FW213 possess a range of mechanisms to avoid host immune clearance, to colonize host tissues, to survive within oral biofilms and to overcome various environmental insults. Furthermore, the comparative genome analysis of five S. parasanguinis strains indicates that albeit S. parasanguinis strains are highly conserved, variations in the genome content exist. These variations may reflect differences in pathogenic potential between the strains.
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Affiliation(s)
- Jianing Geng
- Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Cheng-Hsun Chiu
- Division of Pediatric Infectious Diseases, Molecular Infectious Disease Research Center, Chang Gung Children's Hospital, Tao-Yuan, Taiwan
- Graduate Institute of Basic Medical Sciences, Chang Gung University, Tao-Yuan, Taiwan
| | - Petrus Tang
- Graduate Institute of Basic Medical Sciences, Chang Gung University, Tao-Yuan, Taiwan
- Bioinformatics Center, Chang Gung University, Tao-Yuan, Taiwan
| | - Yaping Chen
- Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, People's Republic of China
- Graduate University of the Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Hui-Ru Shieh
- Graduate Institute of Basic Medical Sciences, Chang Gung University, Tao-Yuan, Taiwan
- Department of Microbiology and Immunology, Chang Gung University, Tao-Yuan, Taiwan
| | - Songnian Hu
- Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Yi-Ywan M. Chen
- Graduate Institute of Basic Medical Sciences, Chang Gung University, Tao-Yuan, Taiwan
- Department of Microbiology and Immunology, Chang Gung University, Tao-Yuan, Taiwan
- * E-mail:
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Aranda J, Teixidó L, Fittipaldi N, Cortés P, Llagostera M, Gottschalk M, Barbé J. Inactivation of the gene encoding zinc-binding lipoprotein 103 impairs the infectivity of Streptococcus suis. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2012; 76:72-76. [PMID: 22754099 PMCID: PMC3244292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 01/19/2011] [Indexed: 06/01/2023]
Abstract
The Streptococcus suis 103 gene product is an immunogenic and protective lipoprotein that is a component of an ATP-binding cassette transporter implicated in zinc uptake. Belonging to the same transcriptional unit and downstream of the 103 gene is a gene that encodes a homologue of the pneumococcal histidine triad (Pht) protein Pht309. In an intraperitoneal mouse model the virulence of a mutant lacking the 103 gene was more than 50 times lower than that of the wild-type (WT) parent strain, S. suis serotype 2 strain P1/7. In addition, the immunogenicity of this mutant was dramatically decreased. In striking contrast, the virulence and immunogenicity of a P1/7 mutant lacking the Pht309 gene were similar to those of the parent strain. These results demonstrate that the 103 lipoprotein is strongly involved in S. suis virulence and support the hypothesis that this lipoprotein might be an excellent candidate for vaccines aiming to achieve broad protection against streptococci.
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Affiliation(s)
- Jesús Aranda
- Department de Genètica i Microbiologia, Edifici C (Facultat de Biociències), Universitat Autònoma de Barcelona (UAB), Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain.
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21
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Abstract
AIM This review intends to provide a brief overview regarding quorum sensing among bacteria in biofilms and also attempts to throw light on the new research focusing on interference with the quorum sensing. BACKGROUND Dental plaque is an example of microbial biofilm leading to periodontal disease and dental caries. Quorum sensing is widely employed by a variety of gram-positive and gram-negative bacterial species to coordinate various activities in biofilms. Quorum-sensing-interfering compounds have either a positive or a negative effect on the expression of bacterial phenotypes regulated by quorum sensing. These studies of bacterial quorum sensing have also suggested several ideal targets for drug design which can be promising in preventive and therapeutic aspects of periodontal diseases and dental caries. RESULTS Studies have shown that periodontal disease and dental caries is caused by plaque biofilm bacteria. Quorum sensing is the means of communication between these bacteria to regulate a wide range of behavior patterns among them. The in vitro studies reviewed here have a vital role in opening up this field, because they reveal the basic machinery of cell--cell signaling in microbial communities. The signal machinery bacteria use to coordinate a variety of their activities is identified by these studies. Further, this review aims to discuss several natural and synthetic methods which were used for manipulating bacterial quorum sensing. CONCLUSION The future challenge lies in the ability of the dental research to develop additional mechanisms for interfering with bacterial quorum sensing which can be used as preventive and therapeutic tools for combating oral polymicrobial diseases. CLINICAL SIGNIFICANCE This article aims at reviewing the literature and helping us to understand the ways of communication among bacteria in biofilms, which further open up the prospects in the treatment of diseases caused by biofilms.
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Affiliation(s)
- Baswaraj Biradar
- Department of Prosthodontics, Indira Gandhi Institute of Dental Sciences, Puducherry, India.
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Abstract
We have characterized group A Streptococcus (GAS) genome-wide responses to hydrogen peroxide and assessed the role of the peroxide response regulator (PerR) in GAS under oxidative stress. Comparison of transcriptome changes elicited by peroxide in wild-type bacteria with those in a perR deletion mutant showed that 76 out of 237 peroxide-regulated genes are PerR dependent. Unlike the PerR-mediated upregulation of peroxidases and other peroxide stress defense mechanisms previously reported in gram-positive species, PerR-dependent genes in GAS were almost exclusively downregulated and encoded proteins involved in purine and deoxyribonucleotide biosynthesis, heme uptake, and amino acid/peptide transport, but they also included a strongly activated putative transcriptional regulator (SPy1198). Of the 161 PerR-independent loci, repressed genes (86 of 161) encoded proteins with functions similar to those coordinated by PerR, in contrast to upregulated loci that encoded proteins that function in DNA damage repair, cofactor metabolism, reactive oxygen species detoxification, pilus biosynthesis, and hypothetical proteins. Complementation of the perR deletion mutant with wild-type PerR restored PerR-dependent regulation, whereas complementation with either one of two PerR variants carrying single mutations in two predicted metal-binding sites did not rescue the mutant phenotype. Metal content analyses of the recombinant wild type and respective PerR mutants, in addition to regulation studies in metal-supplemented and iron-depleted media, showed binding of zinc and iron by PerR and an iron requirement for optimal responses to peroxide. Our findings reveal a novel physiological contribution of PerR in coordinating DNA and protein metabolic functions in peroxide and identify GAS adaptive responses that may serve to enhance oxidative stress resistance and virulence in the host.
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Ogura M. ZnuABC and ZosA zinc transporters are differently involved in competence development in Bacillus subtilis. ACTA ACUST UNITED AC 2011; 150:615-25. [DOI: 10.1093/jb/mvr098] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Shafeeq S, Kloosterman TG, Kuipers OP. Transcriptional response of Streptococcus pneumoniae to Zn2+) limitation and the repressor/activator function of AdcR. Metallomics 2011; 3:609-18. [PMID: 21603707 DOI: 10.1039/c1mt00030f] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Zinc (Zn(2+)) is an important trace metal ion that has been shown to regulate the expression of several (virulence) genes in streptococci. Previously, we analyzed the genome-wide response of S. pneumoniae to Zn(2+)-stress. In this work, we have performed a transcriptomic analysis to identify genes that are differentially expressed under intracellular Zn(2+) limitation. This revealed a number of genes that are highly upregulated in the absence of extracellular Zn(2+), amongst which the genes belonging to the regulon of the Zn(2+)-responsive repressor AdcR, like adcBCA, encoding a Zn(2+)-dependent ABC-uptake system, adcAII, encoding a Zn(2+)-binding lipoprotein, and also virulence genes belonging to the Pht family (phtA, phtB, phtD and phtE). Using transcriptome analysis, lacZ-reporter studies, in vitro DNA binding experiments, and in silico operator predictions, we show that AdcR directly represses the promoters of adcRCBA, adcAII-phtD, phtA, phtB and phtE in the presence of Zn(2+). AdcR can also function as an activator, since in the presence of Zn(2+) it directly induces expression of adh that encodes a Zn(2+)-containing alcohol dehydrogenase. In conclusion, the genome-wide transcriptional response of S. pneumoniae to Zn(2+) limitation was established, which is mainly mediated via direct regulation by the Zn(2+)-dependent regulator AdcR.
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Affiliation(s)
- Sulman Shafeeq
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
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Loisel E, Chimalapati S, Bougault C, Imberty A, Gallet B, Di Guilmi AM, Brown J, Vernet T, Durmort C. Biochemical characterization of the histidine triad protein PhtD as a cell surface zinc-binding protein of pneumococcus. Biochemistry 2011; 50:3551-8. [PMID: 21425866 DOI: 10.1021/bi200012f] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Zinc homeostasis is critical for pathogen host colonization. Indeed, during invasion, Streptococcus pneumoniae has to finely regulate zinc transport to cope with a wide range of Zn(2+) concentrations within the various host niches. AdcAII was identified as a pneumococcal Zn(2+)-binding protein; its gene is present in an operon together with the phtD gene. PhtD belongs to the histidine triad protein family, but to date, its function has not been clarified. Using several complementary biochemical methods, we provide evidence that like AdcAII, PhtD is a metal-binding protein specific for zinc. When Zn(2+) binds (K(d) = 131 ± 10 nM), the protein displays substantial thermal stabilization. We also present the first direct evidence of a joint function of AdcAII and PhtD by demonstrating that their expression is corepressed by Zn(2+), that they interact directly in vitro, and that they are colocalized at the bacterial surface. These results suggest the common involvement of the AdcAII-PhtD system in pneumococcal zinc homeostasis.
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Affiliation(s)
- Elodie Loisel
- CEA, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
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Lactococcus lactis ZitR is a zinc-responsive repressor active in the presence of low, nontoxic zinc concentrations in vivo. J Bacteriol 2011; 193:1919-29. [PMID: 21317326 DOI: 10.1128/jb.01109-10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the family Streptococcaceae, the genes encoding zinc ABC uptake systems (called zit or adc) are regulated by a coencoded MarR family member (i.e., ZitR or AdcR), whereas in the great majority of bacteria, these genes are regulated by Zur, the Fur-like zinc-responsive repressor. We studied the zit operon from Lactococcus lactis and its regulation in response to Zn(II) in vivo. zit transcription is repressed by Zn(II) in a wide concentration range starting from nontoxic micromolar levels and is derepressed at nanomolar concentrations. The level of zit promoter downregulation by environmental Zn(II) is correlated with the intracellular zinc content. The helix-turn-helix domain of ZitR is required for downregulation. In vitro, the purified protein is a dimer that complexes up to two zinc ligands per monomer and specifically binds two intact palindromic operator sites overlapping the -35 and -10 boxes of the zit promoter. DNA binding is abolished by the chelator EDTA or TPEN and fully restored by Zn(II) addition, indicating that the active repressor complexes Zn(II) with high affinity. These results suggest that derepression under starvation conditions could be an essential emergency mechanism for preserving Zn(II) homeostasis by uptake; under Zn(II)-replete conditions, the function of ZitR repression could be to help save energy rather than to avoid Zn(II) toxicity. The characterization of a MarR family zinc-responsive repressor in this report gives insight into the way Streptococcaceae efficiently adapt to Zn(II) fluctuations in their diverse ecological niches.
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Reyes-Caballero H, Guerra AJ, Jacobsen FE, Kazmierczak KM, Cowart D, Koppolu UMK, Scott RA, Winkler ME, Giedroc DP. The metalloregulatory zinc site in Streptococcus pneumoniae AdcR, a zinc-activated MarR family repressor. J Mol Biol 2010; 403:197-216. [PMID: 20804771 DOI: 10.1016/j.jmb.2010.08.030] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/14/2010] [Accepted: 08/16/2010] [Indexed: 12/11/2022]
Abstract
Streptococcus pneumoniae D39 AdcR (adhesin competence repressor) is the first metal-sensing member of the MarR (multiple antibiotic resistance repressor) family to be characterized. Expression profiling with a ΔadcR strain grown in liquid culture (brain-heart infusion) under microaerobic conditions revealed upregulation of 13 genes, including adcR and adcCBA, encoding a high-affinity ABC uptake system for zinc, and genes encoding cell-surface zinc-binding pneumococcal histidine triad (Pht) proteins and AdcAII (Lmb, laminin binding). The ΔadcR, H108Q and H112Q adcR mutant allelic strains grown in 0.2 mM Zn(II) exhibit a slow-growth phenotype and an approximately twofold increase in cell-associated Zn(II). Apo- and Zn(II)-bound AdcR are homodimers in solution and binding to a 28-mer DNA containing an adc operator is strongly stimulated by Zn(II) with K(DNA-Zn)=2.4 × 10(8) M(-1) (pH 6.0, 0.2 M NaCl, 25 °C). AdcR binds two Zn(II) per dimer, with stepwise Zn(II) affinities K(Zn1) and K(Zn2) of ≥10(9) M(-1) at pH 6.0 and ≥10(12) M(-1) at pH 8.0, and one to three lower affinity Zn(II) depending on the pH. X-ray absorption spectroscopy of the high-affinity site reveals a pentacoordinate N/O complex and no cysteine coordination, the latter finding corroborated by wild type-like functional properties of C30A AdcR. Alanine substitution of conserved residues His42 in the DNA-binding domain, and His108 and His112 in the C-terminal regulatory domain, abolish high-affinity Zn(II) binding and greatly reduce Zn(II)-activated binding to DNA. NMR studies reveal that these mutants adopt the same folded conformation as dimeric wild type apo-AdcR, but fail to conformationally switch upon Zn(II) binding. These studies implicate His42, His108 and H112 as metalloregulatory zinc ligands in S. pneumoniae AdcR.
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Ma Z, Jacobsen FE, Giedroc DP. Coordination chemistry of bacterial metal transport and sensing. Chem Rev 2009; 109:4644-81. [PMID: 19788177 PMCID: PMC2783614 DOI: 10.1021/cr900077w] [Citation(s) in RCA: 433] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Zhen Ma
- Department of Chemistry, Indiana University, Bloomington, IN 47401-7005 USA
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128 USA
| | - Faith E. Jacobsen
- Department of Chemistry, Indiana University, Bloomington, IN 47401-7005 USA
| | - David P. Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47401-7005 USA
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Nobbs AH, Lamont RJ, Jenkinson HF. Streptococcus adherence and colonization. Microbiol Mol Biol Rev 2009; 73:407-50, Table of Contents. [PMID: 19721085 PMCID: PMC2738137 DOI: 10.1128/mmbr.00014-09] [Citation(s) in RCA: 428] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Streptococci readily colonize mucosal tissues in the nasopharynx; the respiratory, gastrointestinal, and genitourinary tracts; and the skin. Each ecological niche presents a series of challenges to successful colonization with which streptococci have to contend. Some species exist in equilibrium with their host, neither stimulating nor submitting to immune defenses mounted against them. Most are either opportunistic or true pathogens responsible for diseases such as pharyngitis, tooth decay, necrotizing fasciitis, infective endocarditis, and meningitis. Part of the success of streptococci as colonizers is attributable to the spectrum of proteins expressed on their surfaces. Adhesins enable interactions with salivary, serum, and extracellular matrix components; host cells; and other microbes. This is the essential first step to colonization, the development of complex communities, and possible invasion of host tissues. The majority of streptococcal adhesins are anchored to the cell wall via a C-terminal LPxTz motif. Other proteins may be surface anchored through N-terminal lipid modifications, while the mechanism of cell wall associations for others remains unclear. Collectively, these surface-bound proteins provide Streptococcus species with a "coat of many colors," enabling multiple intimate contacts and interplays between the bacterial cell and the host. In vitro and in vivo studies have demonstrated direct roles for many streptococcal adhesins as colonization or virulence factors, making them attractive targets for therapeutic and preventive strategies against streptococcal infections. There is, therefore, much focus on applying increasingly advanced molecular techniques to determine the precise structures and functions of these proteins, and their regulatory pathways, so that more targeted approaches can be developed.
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Affiliation(s)
- Angela H Nobbs
- Oral Microbiology Unit, Department of Oral and Dental Science, University of Bristol, Bristol BS1 2LY, United Kingdom
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Protective capacities of cell surface-associated proteins of Streptococcus suis mutants deficient in divalent cation-uptake regulators. Microbiology (Reading) 2009; 155:1580-1587. [DOI: 10.1099/mic.0.026278-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many cell surface-associated, divalent cation-regulated proteins are immunogenic, and some of them confer protection against the bacterial species from which they are derived. In this work, two Streptococcus suis divalent cation uptake regulator genes controlling zinc/manganese and iron uptake (adcR and fur, respectively) were inactivated in order to study the protective capacities of their cell surface-associated proteins. The results obtained showed overexpression of a set of immunogenic proteins (including members of the pneumococcal histidine triad family previously reported to confer protection against streptococcal pathogens) in S. suis adcR mutant cell surface extracts. Likewise, genes encoding zinc transporters, putative virulence factors and a ribosomal protein paralogue related to zinc starvation appeared to be derepressed in this mutant strain. Moreover, protection assays in mice showed that although neither adcR- nor fur-regulated cell surface-associated proteins were sufficient to confer protection in mice, the combination of both adcR- and fur-regulated cell surface-associated proteins is able to confer significant protection (50 %, P=0.038) against a challenge to mice vaccinated with them.
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Opposite effects of Mn2+ and Zn2+ on PsaR-mediated expression of the virulence genes pcpA, prtA, and psaBCA of Streptococcus pneumoniae. J Bacteriol 2008; 190:5382-93. [PMID: 18515418 DOI: 10.1128/jb.00307-08] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Homeostasis of Zn(2+) and Mn(2+) is important for the physiology and virulence of the human pathogen Streptococcus pneumoniae. Here, transcriptome analysis was used to determine the response of S. pneumoniae D39 to a high concentration of Zn(2+). Interestingly, virulence genes encoding the choline binding protein PcpA, the extracellular serine protease PrtA, and the Mn(2+) uptake system PsaBC(A) were strongly upregulated in the presence of Zn(2+). Using random mutagenesis, a previously described Mn(2+)-responsive transcriptional repressor, PsaR, was found to mediate the observed Zn(2+)-dependent derepression. In addition, PsaR is also responsible for the Mn(2+)-dependent repression of these genes. Subsequently, we investigated how these opposite effects are mediated by the same regulator. In vitro binding of purified PsaR to the prtA, pcpA, and psaB promoters was stimulated by Mn(2+), whereas Zn(2+) destroyed the interaction of PsaR with its target promoters. Mutational analysis of the pcpA promoter demonstrated the presence of a PsaR operator that mediates the transcriptional effects. In conclusion, PsaR is responsible for the counteracting effects of Mn(2+) and Zn(2+) on the expression of several virulence genes in S. pneumoniae, suggesting that the ratio of these metal ions exerts an important influence on pneumococcal pathogenesis.
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Identification of Streptococcus sanguinis genes required for biofilm formation and examination of their role in endocarditis virulence. Infect Immun 2008; 76:2551-9. [PMID: 18390999 DOI: 10.1128/iai.00338-08] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus sanguinis is one of the pioneers in the bacterial colonization of teeth and is one of the most abundant species in the oral biofilm called dental plaque. S. sanguinis is also the most common viridans group streptococcal species implicated in infective endocarditis. To investigate the association of biofilm and endocarditis, we established a biofilm assay and examined biofilm formation with a signature-tagged mutagenesis library of S. sanguinis. Four genes that have not previously been associated with biofilm formation in any other bacterium, purB, purL, thrB, and pyrE, were putatively identified as contributing to in vitro biofilm formation in S. sanguinis. By examining 800 mutants for attenuation in the rabbit endocarditis model and for reduction in biofilm formation in vitro, we found some mutants that were both biofilm defective and attenuated for endocarditis. However, we also identified mutants with only reduced biofilm formation or with only attenuation in the endocarditis model. This result indicates that the ability to form biofilms in vitro is not associated with endocarditis virulence in vivo in S. sanguinis.
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Analysis of the protective capacity of three Streptococcus suis proteins induced under divalent-cation-limited conditions. Infect Immun 2008; 76:1590-8. [PMID: 18212084 DOI: 10.1128/iai.00987-07] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis is a gram-positive pathogen that causes serious diseases in pigs and, in some cases, humans. Three genes of the virulent S. suis 89/1591 strain, encoding putative divalent-cation-binding lipoproteins, were isolated based on information obtained from the draft annotation files of this organism's genome. The products of these genes, which are inducible by divalent-cation deprivation, were subsequently purified, and their immunogenic and protective abilities were analyzed. All three proteins (SsuiDRAFT 0103, SsuiDRAFT 0174, and SsuiDRAFT 1237) were found to be immunogenic, but only one of them (SsuiDRAFT 0103) induced a significant protective response (87.5%, P = 0.01) against the same S. suis strain. Furthermore, the S. suis ssuiDRAFT 1240 gene (adcR), which encodes a predicted regulator of Zn2+ and/or Mn2+ uptake in streptococci, was cloned, and its protein product was purified. Electrophoretic mobility shift assays with purified S. suis AdcR protein showed experimentally, for the first time, that the AdcR DNA-binding sequence corresponds to the TTAACNRGTTAA motif. In addition, a requirement for either Zn2+ or Mn2+, but not Fe2+, to establish in vitro binding of AdcR to its target sequence and the ability of AdcR to bind the ssuiDRAFT 0103 and ssuiDRAFT 1237 gene promoters but not the promoter of the ssuiDRAFT 0174 gene were demonstrated. Taken together, these data suggest that SsuiDRAFT 0103 is a good candidate for vaccines against S. suis and support preliminary results indicating that bacterial envelope proteins involved in the uptake of divalent cations other than iron may be useful for protective purposes.
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Variation in the group B Streptococcus CsrRS regulon and effects on pathogenicity. J Bacteriol 2008; 190:1956-65. [PMID: 18203834 DOI: 10.1128/jb.01677-07] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CsrRS (or CovRS) is a two-component regulatory system that controls expression of multiple virulence factors in the important human pathogen group B Streptococcus (GBS). We now report global gene expression studies in GBS strains 2603V/R and 515 and their isogenic csrR and csrS mutants. Together with data reported previously for strain NEM316, the results reveal a conserved 39-gene CsrRS regulon. In vitro phosphorylation-dependent binding of recombinant CsrR to promoter regions of both positively and negatively regulated genes suggests that direct binding of CsrR can mediate activation as well as repression of target gene expression. Distinct patterns of gene regulation in csrR versus csrS mutants in strain 2603V/R compared to 515 were associated with different hierarchies of relative virulence of wild-type, csrR, and csrS mutants in murine models of systemic infection and septic arthritis. We conclude that CsrRS regulates a core group of genes including important virulence factors in diverse strains of GBS but also displays marked variability in the repertoire of regulated genes and in the relative effects of CsrS signaling on CsrR-mediated gene regulation. Such variation is likely to play an important role in strain-specific adaptation of GBS to particular host environments and pathogenic potential in susceptible hosts.
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Vickerman MM, Iobst S, Jesionowski AM, Gill SR. Genome-wide transcriptional changes in Streptococcus gordonii in response to competence signaling peptide. J Bacteriol 2007; 189:7799-807. [PMID: 17720781 PMCID: PMC2168715 DOI: 10.1128/jb.01023-07] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus gordonii is a primary colonizer of the multispecies biofilm on tooth surfaces forming dental plaque and a potential agent of endocarditis. The recent completion of the genome sequence of the naturally competent strain Challis allowed the design of a spotted oligonucleotide microarray to examine a genome-wide response of this organism to environmental stimuli such as signal peptides. Based on temporal responses to synthetic competence signaling peptide (CSP) as indicated by transformation frequencies, the S. gordonii transcriptome was analyzed at various time points after CSP exposure. Microarray analysis identified 35 candidate early genes and 127 candidate late genes that were up-regulated at 5 and 15 min, respectively; these genes were often grouped in clusters. Results supported published findings on S. gordonii competence, showing up-regulation of 12 of 16 genes that have been reported to affect transformation frequencies in this species. Comparison of CSP-induced S. gordonii transcriptomes to results published for Streptococcus pneumoniae strains identified both conserved and species-specific genes. Putative intergenic regulatory sites, such as the conserved combox sequence thought to be a binding site for competence sigma factor, were found preceding S. gordonii late responsive genes. In contrast, S. gordonii early CSP-responsive genes were not preceded by the direct repeats found in S. pneumoniae. These studies provide the first insights into a genome-wide transcriptional response of an oral commensal organism. They offer an extensive analysis of transcriptional changes that accompany competence in S. gordonii and form a basis for future intra- and interspecies comparative analyses of this ecologically important phenotype.
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Affiliation(s)
- M M Vickerman
- Department of Periodontics and Endodontics, University at Buffalo School of Dentistry, 223 Foster Hall, 3435 Main St., Buffalo, NY 14214, USA.
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Brenot A, Weston BF, Caparon MG. A PerR-regulated metal transporter (PmtA) is an interface between oxidative stress and metal homeostasis in Streptococcus pyogenes. Mol Microbiol 2007; 63:1185-96. [PMID: 17238923 DOI: 10.1111/j.1365-2958.2006.05577.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In Streptococcus pyogenes, mutation of the peroxide sensor PerR results in avirulence despite producing hyper-resistance to peroxide stress. To understand the basis of this effect, global transcription profiling was conducted revealing one highly downregulated gene (czcD), and five highly upregulated genes in the mutant. Of the latter, only pmtA contained a binding site for PerR, while phtY, phtD, lsp and rpsN2 harboured an AdcR motif and were regulated by AdcR, a repressor of an ABC-type metal transporter. Furthermore, only the PerR-regulated pmtA (PerR-regulated metal transporter A), a putative metal transporter, contributed to resistance against peroxide stress, while AdcR and the other AdcR-regulated genes did not. However, overexpression of pmtA resulted in upregulation of several AdcR-regulated genes, suggesting that the AdcR regulon is sensitive to PerR regulation of metal homeostasis. Finally, examination of S. pyogenes following murine subcutaneous infection revealed that while pmtA was not upregulated in a late infection, the AdcR-regulated genes were. Taken together, these data suggest that PerR has a greater impact on the transcriptome than can be predicted by its binding sites and that pmtA functions to link metal homeostasis and oxidative stress responses.
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Affiliation(s)
- Audrey Brenot
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
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Mueller RS, McDougald D, Cusumano D, Sodhi N, Kjelleberg S, Azam F, Bartlett DH. Vibrio cholerae strains possess multiple strategies for abiotic and biotic surface colonization. J Bacteriol 2007; 189:5348-60. [PMID: 17496082 PMCID: PMC1951843 DOI: 10.1128/jb.01867-06] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Despite its notoriety as a human pathogen, Vibrio cholerae is an aquatic microbe suited to live in freshwater, estuarine, and marine environments where biofilm formation may provide a selective advantage. Here we report characterization of biofilms formed on abiotic and biotic surfaces by two non-O1/O139 V. cholerae strains, TP and SIO, and by the O1 V. cholerae strain N16961 in addition to the isolation of 44 transposon mutants of SIO and TP impaired in biofilm formation. During the course of characterizing the mutants, 30 loci which have not previously been associated with V. cholerae biofilms were identified. These loci code for proteins which perform a wide variety of functions, including amino acid metabolism, ion transport, and gene regulation. Also, when the plankton colonization abilities of strains N16961, SIO, and TP were examined, each strain showed increased colonization of dead plankton compared with colonization of live plankton (the dinoflagellate Lingulodinium polyedrum and the copepod Tigriopus californicus). Surprisingly, most of the biofilm mutants were not impaired in plankton colonization. Only mutants impaired in motility or chemotaxis showed reduced colonization. These results indicate the presence of both conserved and variable genes which influence the surface colonization properties of different V. cholerae subspecies.
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Affiliation(s)
- Ryan S Mueller
- Marine Biology Research Division, Scripps Institution of Oceanography, University of Caifornia, San Diego, La Jolla, CA 92037, USA
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Xu P, Alves JM, Kitten T, Brown A, Chen Z, Ozaki LS, Manque P, Ge X, Serrano MG, Puiu D, Hendricks S, Wang Y, Chaplin MD, Akan D, Paik S, Peterson DL, Macrina FL, Buck GA. Genome of the opportunistic pathogen Streptococcus sanguinis. J Bacteriol 2007; 189:3166-75. [PMID: 17277061 PMCID: PMC1855836 DOI: 10.1128/jb.01808-06] [Citation(s) in RCA: 177] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome of Streptococcus sanguinis is a circular DNA molecule consisting of 2,388,435 bp and is 177 to 590 kb larger than the other 21 streptococcal genomes that have been sequenced. The G+C content of the S. sanguinis genome is 43.4%, which is considerably higher than the G+C contents of other streptococci. The genome encodes 2,274 predicted proteins, 61 tRNAs, and four rRNA operons. A 70-kb region encoding pathways for vitamin B(12) biosynthesis and degradation of ethanolamine and propanediol was apparently acquired by horizontal gene transfer. The gene complement suggests new hypotheses for the pathogenesis and virulence of S. sanguinis and differs from the gene complements of other pathogenic and nonpathogenic streptococci. In particular, S. sanguinis possesses a remarkable abundance of putative surface proteins, which may permit it to be a primary colonizer of the oral cavity and agent of streptococcal endocarditis and infection in neutropenic patients.
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Affiliation(s)
- Ping Xu
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA 23284-2030, USA
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Abstract
Two areas of research have recently converged to highlight important roles for Mn(2+) in pathogenesis: the recognition that both bacterial Nramp homologs and members of LraI family of proteins are Mn(2+) transporters. Their mutation is associated with decreased virulence of various bacterial species. Thus, Mn(2+) appears to be essential for bacterial virulence. This review describes what is currently known about Mn(2+) transport in prokaryotes and how prokaryotic Mn(2+) transport is regulated. Some of the phenotypes that arise when microorganisms lack Mn(2+) are then discussed, with an emphasis on those phenotypes involving pathogenesis. The concluding section describes possible enzymatic roles for Mn(2+) that might help explain why Mn(2+) is necessary for virulence.
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Affiliation(s)
- Mary E Davey
- Department of Molecular Genetics, The Forsyth Institute, Boston, Massachusetts, USA
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Rolerson E, Swick A, Newlon L, Palmer C, Pan Y, Keeshan B, Spatafora G. The SloR/Dlg metalloregulator modulates Streptococcus mutans virulence gene expression. J Bacteriol 2006; 188:5033-44. [PMID: 16816176 PMCID: PMC1539950 DOI: 10.1128/jb.00155-06] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Metal ion availability in the human oral cavity plays a putative role in Streptococcus mutans virulence gene expression and in appropriate formation of the plaque biofilm. In this report, we present evidence that supports such a role for the DtxR-like SloR metalloregulator (called Dlg in our previous publications) in this oral pathogen. Specifically, the results of gel mobility shift assays revealed the sloABC, sloR, comDE, ropA, sod, and spaP promoters as targets of SloR binding. We confirmed differential expression of these genes in a GMS584 SloR-deficient mutant versus the UA159 wild-type progenitor by real-time semiquantitative reverse transcriptase PCR experiments. The results of additional expression studies support a role for SloR in S. mutans control of glucosyltransferases, glucan binding proteins, and genes relevant to antibiotic resistance. Phenotypic analysis of GMS584 revealed that it forms aberrant biofilms on an abiotic surface, is compromised for genetic competence, and demonstrates heightened incorporation of iron and manganese as well as resistance to oxidative stress compared to the wild type. Taken together, these findings support a role for SloR in S. mutans adherence, biofilm formation, genetic competence, metal ion homeostasis, oxidative stress tolerance, and antibiotic gene regulation, all of which contribute to S. mutans-induced disease.
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Affiliation(s)
- Elizabeth Rolerson
- Department of Biology, Middlebury College, 276 Bicentennial Way, MBH354, Middlebury, Vermont 05753, USA
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Gallaher TK, Wu S, Webster P, Aguilera R. Identification of biofilm proteins in non-typeable Haemophilus Influenzae. BMC Microbiol 2006; 6:65. [PMID: 16854240 PMCID: PMC1559630 DOI: 10.1186/1471-2180-6-65] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Accepted: 07/19/2006] [Indexed: 11/18/2022] Open
Abstract
Background Non-typeable Haemophilus influenzae biofilm formation is implicated in a number of chronic infections including otitis media, sinusitis and bronchitis. Biofilm structure includes cells and secreted extracellular matrix that is "slimy" and believed to contribute to the antibiotic resistant properties of biofilm bacteria. Components of biofilm extracellular matrix are largely unknown. In order to identify such biofilm proteins an ex-vivo biofilm of a non-typeable Haemophilus influenzae isolate, originally from an otitis media patent, was produced by on-filter growth. Extracellular matrix fraction was subjected to proteomic analysis via LC-MS/MS to identify proteins. Results 265 proteins were identified in the extracellular matrix sample. The identified proteins were analyzed for COG grouping and predicted cellular location via the TMHMM and SignalP predictive algorithms. The most over-represented COG groups identified compared to their frequency in the Haemophilus influenzae genome were cell motility and secretion (group N) followed by ribosomal proteins of group J. A number of hypothetical or un-characterized proteins were observed, as well as proteins previously implicated in biofilm function. Conclusion This study represents an initial approach to identifying and cataloguing numerous proteins associated with biofilm structure. The approach can be applied to biofilms of other bacteria to look for commonalities of expression and obtained information on biofilm protein expression can be used in multidisciplinary approaches to further understand biofilm structure and function.
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Affiliation(s)
- Timothy K Gallaher
- Proteomic Core Facility, School of Pharmacy, Health Sciences Campus, University of Southern California, Los Angeles, CA 90033, USA
| | - Siva Wu
- Ahmanson Advanced Electron Microscopy and Imaging Center, House Ear Institute, 2100 West Third Street, Los Angeles, CA 90057, USA
| | - Paul Webster
- Ahmanson Advanced Electron Microscopy and Imaging Center, House Ear Institute, 2100 West Third Street, Los Angeles, CA 90057, USA
| | - Rodrigo Aguilera
- Proteomic Core Facility, School of Pharmacy, Health Sciences Campus, University of Southern California, Los Angeles, CA 90033, USA
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Kuboniwa M, Tribble GD, James CE, Kilic AO, Tao L, Herzberg MC, Shizukuishi S, Lamont RJ. Streptococcus gordonii utilizes several distinct gene functions to recruit Porphyromonas gingivalis into a mixed community. Mol Microbiol 2006; 60:121-39. [PMID: 16556225 DOI: 10.1111/j.1365-2958.2006.05099.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dental plaque biofilm formation proceeds through a developmental pathway initiated by the attachment of pioneer organisms, such as Streptococcus gordonii, to tooth surfaces. Through a variety of synergistic interactions, pioneer organisms facilitate the colonization of later arrivals including Porphyromonas gingivalis, a potential periodontal pathogen. We have investigated genes of S. gordonii required to support a heterotypic biofilm community with P. gingivalis. By screening a plasmid integration library of S. gordonii, genes were identified that are crucial for the accumulation of planktonic P. gingivalis cells into a multispecies biofilm. These genes were further investigated by specific mutation and complementation analyses. The biofilm-associated genes can be grouped into broad categories based on putative function as follows: (i) intercellular or intracellular signalling (cbe and spxB), (ii) cell wall integrity and maintenance of adhesive proteins (murE, msrA and atf), (iii) extracellular capsule biosynthesis (pgsA and atf), and (iv) physiology (gdhA, ccmA and ntpB). In addition, a gene for a hypothetical protein was identified. Biofilm visualization and quantification by confocal microscopy confirmed the role of these genes in the maturation of the multispecies community, including biofilm architectural development. The results suggest that S. gordonii governs the development of heterotypic oral biofilms through multiple genetic pathways.
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Affiliation(s)
- Masae Kuboniwa
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA
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Baker-Austin C, Wright MS, Stepanauskas R, McArthur JV. Co-selection of antibiotic and metal resistance. Trends Microbiol 2006; 14:176-82. [PMID: 16537105 DOI: 10.1016/j.tim.2006.02.006] [Citation(s) in RCA: 1064] [Impact Index Per Article: 59.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 02/02/2006] [Accepted: 02/23/2006] [Indexed: 11/25/2022]
Abstract
There is growing concern that metal contamination functions as a selective agent in the proliferation of antibiotic resistance. Documented associations between the types and levels of metal contamination and specific patterns of antibiotic resistance suggest that several mechanisms underlie this co-selection process. These co-selection mechanisms include co-resistance (different resistance determinants present on the same genetic element) and cross-resistance (the same genetic determinant responsible for resistance to antibiotics and metals). Indirect but shared regulatory responses to metal and antibiotic exposure such as biofilm induction also represent potential co-selection mechanisms used by prokaryotes. Metal contamination, therefore, represents a long-standing, widespread and recalcitrant selection pressure with both environmental and clinical importance that potentially contributes to the maintenance and spread of antibiotic resistance factors.
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45
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Martín-Galiano AJ, Overweg K, Ferrándiz MJ, Reuter M, Wells JM, de la Campa AG. Transcriptional analysis of the acid tolerance response in Streptococcus pneumoniae. Microbiology (Reading) 2005; 151:3935-3946. [PMID: 16339938 DOI: 10.1099/mic.0.28238-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Streptococcus pneumoniae, one of the major causes of morbidity and mortality in humans, faces a range of potentially acidic conditions in the middle and late stages of growthin vitro, in diverse human fluids during the infection process, and in biofilms present in the nasopharynx of carriers.S. pneumoniaewas shown to develop a weak acid tolerance response (ATR), where cells previously exposed to sublethal pHs (5·8–6·6) showed an increased survival rate of up to one order of magnitude after challenge at the lethal pH (4·4, survival rate of 10−4). Moreover, the survival after challenge of stationary phase cells at pH 4·4 was three orders of magnitude higher than that of cells taken from the exponential phase, due to the production of lactic acid during growth and increasing acidification of the growth medium until stationary phase. Global expression analysis after short-term (5, 15 and 30 min, the adaptation phase) and long-term (the maintenance phase) acidic shock (pH 6·0) was performed by microarray experiments, and the results were validated by real-time RT-PCR. Out of a total of 126 genes responding to acidification, 59 and 37 were specific to the adaptation phase and maintenance phase, respectively, and 30 were common to both periods. In the adaptation phase, both up- and down-regulation of gene transcripts was observed (38 and 21 genes, respectively), whereas in the maintenance phase most of the affected genes were down-regulated (34 out of 37). Genes involved in protein fate (including those involved in the protection of the protein native structure) and transport (including transporters of manganese and iron) were overrepresented among the genes affected by acidification, 8·7 and 24·6 % of the acid-responsive genes compared to 2·8 % and 9·6 % of the genome complement, respectively. Cross-regulation with the response to oxidative and osmotic stress was observed. Potential regulatory motifs involved in the ATR were identified in the promoter regions of some of the regulated genes.
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Affiliation(s)
- Antonio J Martín-Galiano
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220, Majadahonda, Madrid, Spain
| | - Karin Overweg
- Bacterial Infection and Immunity Group, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK
| | - Maria J Ferrándiz
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220, Majadahonda, Madrid, Spain
| | - Mark Reuter
- Bacterial Infection and Immunity Group, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK
| | - Jerry M Wells
- Bacterial Infection and Immunity Group, Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK
| | - Adela G de la Campa
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220, Majadahonda, Madrid, Spain
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Mitrakul K, Loo CY, Gyurko C, Hughes CV, Ganeshkumar N. Mutational analysis of the adcCBA genes in Streptococcus gordonii biofilm formation. ACTA ACUST UNITED AC 2005; 20:122-7. [PMID: 15720574 DOI: 10.1111/j.1399-302x.2004.00205.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Streptococcus gordonii, a primary colonizer, is part of the pioneer biofilm consortium that initiates dental plaque development on tooth surfaces. An insertion of Tn917-lac transposon into the adcR gene produced a biofilm-defective phenotype. S. gordonii adcR is a regulatory gene and is part of an operon (adc) that includes three other genes, adcCBA. AdcC contains a putative consensus-binding site for adenosine triphosphate, AdcB is a putative hydrophobic membrane protein, and AdcA is a putative lipoprotein permease. Mutants were constructed by insertional inactivation in each of the three adcCBA genes and their effects on biofilm formation examined. The adcC::spec(R) and adcB::spec(R) mutations displayed a biofilm-defective phenotype, whereas the adcA::spec(R) mutant was biofilm-positive in a static polystyrene microtiter plate biofilm assay. All three mutants formed poor biofilms in a flow-cell system and were competence-defective, suggesting the adc operon plays an important role in S. gordonii biofilm formation and competence.
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Affiliation(s)
- K Mitrakul
- Department of Pediatric Dentistry, Goldman School of Dental Medicine, Boston University, Boston, MA, USA
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47
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Loo CY, Mitrakul K, Jaafar S, Gyurko C, Hughes CV, Ganeshkumar N. Role of a nosX homolog in Streptococcus gordonii in aerobic growth and biofilm formation. J Bacteriol 2005; 186:8193-206. [PMID: 15576767 PMCID: PMC532431 DOI: 10.1128/jb.186.24.8193-8206.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Oral streptococci such as Streptococcus gordonii are facultative anaerobes that initiate biofilm formation on tooth surfaces. An isolated S. gordonii::Tn917-lac biofilm-defective mutant contained a transposon insertion in an open reading frame (ORF) encoding a homolog of NosX of Ralstonia eutropha, a putative maturation factor of nitrous oxide reductase. Located downstream are two genes, qor1 and qor2, predicted to encode two putative NADPH quinone oxidoreductases. These three genes are cotranscribed, forming a putative oxidative stress response (osr) operon in S. gordonii. Inactivation of nosX, qor1, or qor2 resulted in biofilm-defective phenotypes. Expression of nosX, measured by the beta-galactosidase activity of the nosX::Tn917-lac mutant, was growth-phase dependent and enhanced when grown under aerobic conditions or in the presence of paraquat. Real-time reverse transcription-PCR revealed that nosX-specific mRNA levels were increased approximately 8.4 and 3.5 fold in biofilm-derived cells grown on plastic and glass, respectively, when compared to planktonic cells. Expression of nosX increased 19.9 fold in cells grown under aerated aerobic conditions and 4.7 fold in cells grown under static aerobic conditions. Two ORFs immediately adjacent to the osr operon encode a putative NADH oxidase (Nox) and a putative thiol-specific antioxidant enzyme (AhpC, for alkyl hydroperoxide peroxidase C). Expression of nox and ahpC was also significantly increased in cells grown under aerated and static aerobic conditions when compared to anaerobic conditions. In addition, nox expression was increased in biofilm cells compared to planktonic cells. These genes may be part of an island that deals with oxidoreductive response, some of which may be important in S. gordonii biofilm formation.
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Affiliation(s)
- C Y Loo
- Department of Pediatric Dentistry, Goldman School of Dental Medicine, Boston University, 801 Albany St., Room 215, Boston, MA 02118, USA
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48
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Mitrakul K, Loo CY, Hughes CV, Ganeshkumar N. Role of a Streptococcus gordonii copper-transport operon, copYAZ, in biofilm detachment. ACTA ACUST UNITED AC 2005; 19:395-402. [PMID: 15491466 DOI: 10.1111/j.1399-302x.2004.00176.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Streptococcus gordonii is a pioneer oral bacterium that is associated with the initiation of dental plaque development. Located downstream of the S. gordonii adc operon, which is involved in competence and biofilm formation, were three open reading frames, designated copY, copA and copZ. These open reading frames were homologous to the copYAZ genes in Streptococcus mutans that are involved in copper homeostasis and biofilm detachment. This study examined whether copYAZ genes play any role in the biofilm formation and detachment of S. gordonii. The copY gene encodes a 143-amino acid protein homologous to the negative transcriptional regulator of a copper-transport operon, copA encodes a 748-amino acid copper-transporting P-type ATPase, and copZ encodes a 69-amino acid putative metallochaperone protein in S. mutans. Each open reading frame in the copYAZ operon in S. gordonii was inactivated by insertional mutation and the growth, biofilm formation and detachment of each mutant were examined. S. gordonii copY::specR, copA::specR, and copZ::specR mutants were able to form biofilms on both polystyrene and glass surfaces. However, inactivation of copZ and to a lesser extent copY resulted in phenotypes that were defective in biofilm detachment, which is consistent with previous observations in S. mutans and suggests that the trace element copper might influence biofilm detachment of bacterial biofilms.
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Affiliation(s)
- K Mitrakul
- Department of Pediatric Dentistry, Goldman School of Dental Medicine, Boston University, Boston, MA 02118, USA
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49
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Welin J, Wilkins JC, Beighton D, Svensäter G. Protein expression by Streptococcus mutans during initial stage of biofilm formation. Appl Environ Microbiol 2004; 70:3736-41. [PMID: 15184181 PMCID: PMC427790 DOI: 10.1128/aem.70.6.3736-3741.2004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cells growing on surfaces in biofilms exhibit properties distinct from those of planktonic cells, such as increased resistance to biocides and antimicrobial agents. In spite of increased interest in biofilms, very little is known about alterations in cell physiology that occur upon attachment of cells to a surface. In this study we have investigated the changes induced in the protein synthesis by contact of Streptococcus mutans with a surface. Log-phase planktonic cells of S. mutans were allowed to adhere to a glass slide for 2 h in the presence of a (14)C-amino acid mixture. Nonadhered cells were washed away, and the adhered cells were removed by sonication. The proteins were extracted from the nonadhered planktonic and the adhered biofilm cells and separated by two-dimensional gel electrophoresis followed by autoradiography and image analysis. Image analysis revealed that the relative rate of synthesis of 25 proteins was enhanced and that of 8 proteins was diminished > or =1.3-fold in the biofilm cells. Proteins of interest were identified by mass spectrometry and computer-assisted protein sequence analysis. Of the 33 proteins associated with the adhesion response, all but 10 were identified by mass spectrometry and peptide mass fingerprinting. The most prominent change in adhered cells was the increase in relative synthesis of enzymes involved in carbohydrate catabolism indicating that a redirection in protein synthesis towards energy generation is an early response to contact with and adhesion to a surface.
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Affiliation(s)
- J Welin
- Department of Oral Biology, Faculty of Odontology, Malmö University, SE-205 06 Malmo, Sweden
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50
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Kiliç AO, Tao L, Zhang Y, Lei Y, Khammanivong A, Herzberg MC. Involvement of Streptococcus gordonii beta-glucoside metabolism systems in adhesion, biofilm formation, and in vivo gene expression. J Bacteriol 2004; 186:4246-53. [PMID: 15205427 PMCID: PMC421613 DOI: 10.1128/jb.186.13.4246-4253.2004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus gordonii genes involved in beta-glucoside metabolism are induced in vivo on infected heart valves during experimental endocarditis and in vitro during biofilm formation on saliva-coated hydroxyapatite (sHA). To determine the roles of beta-glucoside metabolism systems in biofilm formation, the loci of these induced genes were analyzed. To confirm the function of genes in each locus, strains were constructed with gene inactivation, deletion, and/or reporter gene fusions. Four novel systems responsible for beta-glucoside metabolism were identified, including three phosphoenolpyruvate-dependent phosphotransferase systems (PTS) and a binding protein-dependent sugar uptake system for metabolizing multiple sugars, including beta-glucosides. Utilization of arbutin and esculin, aryl-beta-glucosides, was defective in some mutants. Esculin and oligochitosaccharides induced genes in one of the three beta-glucoside metabolism PTS and in four other genetic loci. Mutation of genes in any of the four systems affected in vitro adhesion to sHA, biofilm formation on plastic surfaces, and/or growth rate in liquid medium. Therefore, genes associated with beta-glucoside metabolism may regulate S. gordonii in vitro adhesion, biofilm formation, growth, and in vivo colonization.
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Affiliation(s)
- Ali O Kiliç
- Department of Oral Biology, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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