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Kreth J, Merritt J, Pfeifer C, Khajotia S, Ferracane J. Interaction between the Oral Microbiome and Dental Composite Biomaterials: Where We Are and Where We Should Go. J Dent Res 2020; 99:1140-1149. [PMID: 32479134 PMCID: PMC7443996 DOI: 10.1177/0022034520927690] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dental composites are routinely placed as part of tooth restoration procedures. The integrity of the restoration is constantly challenged by the metabolic activities of the oral microbiome. This activity directly contributes to a less-than-desirable half-life for the dental composite formulations currently in use. Therefore, many new antimicrobial dental composites are being developed to counteract the microbial challenge. To ensure that these materials will resist microbiome-derived degradation, the model systems used for testing antimicrobial activities should be relevant to the in vivo environment. Here, we summarize the key steps in oral microbial colonization that should be considered in clinically relevant model systems. Oral microbial colonization is a clearly defined developmental process that starts with the formation of the acquired salivary pellicle on the tooth surface, a conditioned film that provides the critical attachment sites for the initial colonizers. Further development includes the integration of additional species and the formation of a diverse, polymicrobial mature biofilm. Biofilm development is discussed in the context of dental composites, and recent research is highlighted regarding the effect of antimicrobial composites on the composition of the oral microbiome. Future challenges are addressed, including the potential of antimicrobial resistance development and how this could be counteracted by detailed studies of microbiome composition and gene expression on dental composites. Ultimately, progress in this area will require interdisciplinary approaches to effectively mitigate the inevitable challenges that arise as new experimental bioactive composites are evaluated for potential clinical efficacy. Success in this area could have the added benefit of inspiring other fields in medically relevant materials research, since microbial colonization of medical implants and devices is a ubiquitous problem in the field.
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Affiliation(s)
- J. Kreth
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, USA
| | - J. Merritt
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, USA
| | - C.S. Pfeifer
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - S. Khajotia
- Department of Restorative Sciences, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - J.L. Ferracane
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
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2
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Cheng X, Redanz S, Treerat P, Qin H, Choi D, Zhou X, Xu X, Merritt J, Kreth J. Magnesium-Dependent Promotion of H 2O 2 Production Increases Ecological Competitiveness of Oral Commensal Streptococci. J Dent Res 2020; 99:847-854. [PMID: 32197054 PMCID: PMC7313347 DOI: 10.1177/0022034520912181] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The pyruvate oxidase (SpxB)-dependent production of H2O2 is widely distributed among oral commensal streptococci. Several studies confirmed the ability of H2O2 to antagonize susceptible oral bacterial species, including caries-associated Streptococcus mutans as well as several periodontal pathobionts. Here we report a potential mechanism to bolster oral commensal streptococcal H2O2 production by magnesium (Mg2+) supplementation. Magnesium is a cofactor for SpxB catalytic activity, and supplementation increases the production of H2O2 in vitro. We demonstrate that Mg2+ affects spxB transcription and SpxB abundance in Streptococcus sanguinis and Streptococcus gordonii. The competitiveness of low-passage commensal streptococcal clinical isolates is positively influenced in antagonism assays against S. mutans. In growth conditions normally selective for S. mutans, Mg2+ supplementation is able to increase the abundance of S. sanguinis in dual-species biofilms. Using an in vivo biophotonic imaging platform, we further demonstrate that dietary Mg2+ supplementation significantly improves S. gordonii oral colonization in mice. In summary, our results support a role for Mg2+ supplementation as a potential prebiotic to promote establishment of oral health-associated commensal streptococci.
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Affiliation(s)
- X. Cheng
- The State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China,Department of Geriatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - S. Redanz
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA
| | - P. Treerat
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA
| | - H. Qin
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA
| | - D. Choi
- Department of Community Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA,School of Public Health, Oregon Health & Science University, Portland, OR, USA
| | - X. Zhou
- The State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - X. Xu
- The State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China,Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - J. Merritt
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA,Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - J. Kreth
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA,Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA,J. Kreth, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd., MRB433, Portland, OR 97239, USA.
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3
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Kreth J, Ferracane J, Pfeifer C, Khajotia S, Merritt J. At the Interface of Materials and Microbiology: A Call for the Development of Standardized Approaches to Assay Biomaterial-Biofilm Interactions. J Dent Res 2019; 98:850-852. [PMID: 31173560 PMCID: PMC6616120 DOI: 10.1177/0022034519854685] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Affiliation(s)
- J. Kreth
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, USA
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA
| | - J.L. Ferracane
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - C.S. Pfeifer
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - S. Khajotia
- Department of Restorative Sciences, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - J. Merritt
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, USA
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA
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4
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Valdebenito B, Tullume-Vergara PO, González W, Kreth J, Giacaman RA. In silico analysis of the competition between Streptococcus sanguinis and Streptococcus mutans in the dental biofilm. Mol Oral Microbiol 2018; 33:168-180. [PMID: 29237244 DOI: 10.1111/omi.12209] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2017] [Indexed: 01/03/2023]
Abstract
During dental caries, the dental biofilm modifies the composition of the hundreds of involved bacterial species. Changing environmental conditions influence competition. A pertinent model to exemplify the complex interplay of the microorganisms in the human dental biofilm is the competition between Streptococcus sanguinis and Streptococcus mutans. It has been reported that children and adults harbor greater numbers of S. sanguinis in the oral cavity, associated with caries-free teeth. Conversely, S. mutans is predominant in individuals with a high number of carious lesions. Competition between both microorganisms stems from the production of H2 O2 by S. sanguinis and mutacins, a type of bacteriocins, by S. mutans. There is limited evidence on how S. sanguinis survives its own H2 O2 levels, or if it has other mechanisms that might aid in the competition against S. mutans, nonetheless. We performed a genomic and metabolic pathway comparison, coupled with a comprehensive literature review, to better understand the competition between these two species. Results indicated that S. sanguinis can outcompete S. mutans by the production of an enzyme capable of metabolizing H2 O2 . S. mutans, however, lacks the enzyme and is susceptible to the peroxide from S. sanguinis. In addition, S. sanguinis can generate energy through gluconeogenesis and seems to have evolved different communication mechanisms, indicating that novel proteins may be responsible for intra-species communication.
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Affiliation(s)
- B Valdebenito
- Centro de Bioinformática y Simulación Molecular (CBSM), University of Talca, Talca, Chile
| | - P O Tullume-Vergara
- Facultad de Ciencias Biológicas, Universidad Nacional Pedro Ruiz Gallo, Lambayeque, Peru
| | - W González
- Centro de Bioinformática y Simulación Molecular (CBSM), University of Talca, Talca, Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Talca, Chile
| | - J Kreth
- Department of Restorative Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - R A Giacaman
- Cariology Unit, Department of Oral Rehabilitation and Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), University of Talca, Talca, Chile
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Chen Z, Mashburn-Warren L, Merritt J, Federle MJ, Kreth J. Interference of a speB 5' untranslated region partial deletion with mRNA degradation in Streptococcus pyogenes. Mol Oral Microbiol 2017; 32:390-403. [PMID: 28371435 PMCID: PMC10030001 DOI: 10.1111/omi.12181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2017] [Indexed: 01/28/2023]
Abstract
The 5' untranslated region (5' UTR) of an mRNA molecule embeds important determinants that modify its stability and translation efficiency. In Streptococcus pyogenes, a strict human pathogen, a gene encoding a secreted protease (speB) has a large 5' UTR with unknown functions. Here we describe that a partial deletion of the speB 5' UTR caused a general accumulation of mRNA in the stationary phase, and that the mRNA accumulation was due to retarded mRNA degradation. The phenotype was observed in several M serotypes harboring the partial deletion of the speB 5' UTR. The phenotype was triggered by the production of the truncated speB 5' UTR, but not by the disruption of the intact speB 5' UTR. RNase Y, a major endoribonuclease, was previously shown to play a central role in bulk mRNA turnover in stationary phase. However, in contrast to our expectations, we observed a weaker interaction between the truncated speB 5' UTR and RNase Y compared with the wild-type, which suggests that other unidentified RNA degrading components are required for the pleiotropic effects observed from the speB UTR truncation. Our study demonstrates how S. pyogenes uses distinct mRNA degradation schemes in exponential and stationary growth phases.
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Affiliation(s)
- Z Chen
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - L Mashburn-Warren
- Center for Microbial Pathogenesis, The Research Institute, Nationwide Children's Hospital, Columbus, OH, USA
| | - J Merritt
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - M J Federle
- Center for Biomolecular Sciences, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - J Kreth
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
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6
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Itzek A, Chen Z, Merritt J, Kreth J. Effect of salivary agglutination on oral streptococcal clearance by human polymorphonuclear neutrophil granulocytes. Mol Oral Microbiol 2016; 32:197-210. [PMID: 27194631 DOI: 10.1111/omi.12164] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2016] [Indexed: 12/20/2022]
Abstract
Salivary agglutination is an important host defense mechanism to aggregate oral commensal bacteria as well as invading pathogens. Saliva flow and subsequent swallowing more easily clear aggregated bacteria compared with single cells. Phagocytic clearance of bacteria through polymorphonuclear neutrophil granulocytes also seems to increase to a certain extent with the size of bacterial aggregates. To determine a connection between salivary agglutination and the host innate immune response by phagocytosis, an in vitro agglutination assay was developed reproducing the average size of salivary bacterial aggregates. Using the oral commensal Streptococcus gordonii as a model organism, the effect of salivary agglutination on phagocytic clearance through polymorphonuclear neutrophil granulocytes was investigated. Here we describe how salivary aggregates of S. gordonii are readily cleared through phagocytosis, whereas single bacterial cells showed a significant delay in being phagocytosed and killed. Furthermore, before phagocytosis the polymorphonuclear neutrophil granulocytes were able to induce a specific de-aggregation, which was dependent on serine protease activity. The data presented suggest that salivary agglutination of bacterial cells leads to an ideal size for recognition by polymorphonuclear neutrophil granulocytes. As a first line of defense, these phagocytic cells are able to recognize the aggregates and de-aggregate them via serine proteases to a more manageable size for efficient phagocytosis and subsequent killing in the phagolysosome. This observed mechanism not only prevents the rapid spreading of oral bacterial cells while entering the bloodstream but would also avoid degranulation of involved polymorphonuclear neutrophil granulocytes, so preventing collateral damage to nearby tissue.
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Affiliation(s)
- A Itzek
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Z Chen
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - J Merritt
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - J Kreth
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
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7
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Florez F, Hiers R, Smart K, Kreth J, Qi F, Merritt J, Khajotia S. Non-destructive assessment of biofilm metabolism on resin composite. Dent Mater 2016. [DOI: 10.1016/j.dental.2016.08.199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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Abstract
Streptococcus gordonii is an important member of the oral biofilm community. As an oral commensal streptococcus, S. gordonii is considered beneficial in promoting biofilm homeostasis. CcpA is known as the central regulator of carbon catabolite repression in Gram-positive bacteria and is also involved in the control of virulence gene expression. To further establish the role of CcpA as central regulator in S. gordonii, the effect of CcpA on biofilm formation and natural competence of S. gordonii was investigated. These phenotypic traits have been suggested to be important to oral streptococci in coping with environmental stress. Here we demonstrate that a CcpA mutant was severely impaired in its biofilm-forming ability, showed a defect in extracellular polysaccharide production and reduced competence. The data suggest that CcpA is involved in the regulation of biofilm formation and competence development in S. gordonii.
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Affiliation(s)
- L Zheng
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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9
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Welk A, Rudolph P, Kreth J, Schwahn C, Kramer A, Below H. Microbicidal efficacy of thiocyanate hydrogen peroxide after adding lactoperoxidase under saliva loading in the quantitative suspension test. Arch Oral Biol 2011; 56:1576-82. [DOI: 10.1016/j.archoralbio.2011.04.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 03/15/2011] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
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10
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Lei Y, Zhang Y, Guenther BD, Kreth J, Herzberg MC. Mechanism of adhesion maintenance by methionine sulphoxide reductase in Streptococcus gordonii. Mol Microbiol 2011; 80:726-38. [PMID: 21410565 DOI: 10.1111/j.1365-2958.2011.07603.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methionine sulphoxide reductase maintains adhesin function during oxidative stress. Using Streptococcus gordonii as a model, we now show the mechanistic basis of adhesin maintenance provided by MsrA. In biofilms, S. gordonii selectively expresses the msrA gene. When the wild-type strain was grown with exogenous hydrogen peroxide (H(2)O(2)), msrA-specific mRNA expression significantly increased, while acid production was unaffected. In the presence of H(2)O(2), a msrA-deletion mutant (ΔMsrA) showed a 6 h delay in lag phase growth, a 30% lower yield of H(2)O(2), significantly greater inhibition by H(2)O(2) on agar plates (reversed by complementation), 30% less adhesion to saliva-coated hydroxyapatite, 87% less biofilm formation and an altered electrophoretic pattern of SspAB protein adhesins. Using mass spectrometry, methionine residues in the Met-rich central region of SspB were shown to be oxidized by H(2)O(2) and reduced by MsrA. In intact wild-type cells, MsrA colocalized with a cell wall-staining dye, and MsrA was detected in both cell wall and cytosolic fractions. To maintain normal adhesion and biofilm function of S. gordonii in response to exogenous oxidants therefore msrA is upregulated, methionine oxidation of adhesins and perhaps other proteins is reversed, and adhesion and biofilm formation is maintained.
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Affiliation(s)
- Y Lei
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
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11
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Zhu L, Zhang Y, Fan J, Herzberg MC, Kreth J. Characterization of competence and biofilm development of a Streptococcus sanguinis endocarditis isolate. Mol Oral Microbiol 2011; 26:117-26. [PMID: 21375702 DOI: 10.1111/j.2041-1014.2010.00602.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Streptococcus sanguinis is an oral commensal bacterium and endogenous pathogen in the blood, which is generally naturally competent to take up extracellular DNA. Regarded as a stress response, competence development enables S. sanguinis to acquire new genetic material. The sequenced reference strain SK36 encodes and expresses the genes required for competence (com) and uptake of DNA. Isolated from blood cultures of a confirmed case of infective endocarditis, strain 133-79 encodes all necessary com genes but is not transformable under conditions permissive for competence development in SK36. Using synthetic competence-stimulating peptides (sCSP) based on sequences of SK36 and 133-79 comC, both strains developed competence at similar frequencies in cross-transformation experiments. Furthermore, downstream response pathways are similar in strains SK36 and 133-79 because platelet aggregation and biofilm formation appeared unaffected by CSP. Collectively, the data indicate that strains SK36 and 133-79 respond to CSP similarly, strongly suggesting that endogenous production or release of CSP from 133-79 is impaired.
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Affiliation(s)
- L Zhu
- College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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13
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Kreth J, Kim D, Nguyen M, Hsiao G, Mito R, Kang MK, Chugal N, Shi W. The Antimicrobial Effect of Silver Ion Impregnation into Endodontic Sealer against Streptococcus mutans. Open Dent J 2008; 2:18-23. [PMID: 19088878 PMCID: PMC2581525 DOI: 10.2174/1874210600802010018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Accepted: 01/10/2008] [Indexed: 11/29/2022] Open
Abstract
Pulpal and periradicular diseases are primarily caused by bacterial invasion of the root canal system as a result of caries progression. The presence of residual bacteria at the time of root canal completion (obturation) is associated with significantly higher rate of treatment failure. Re-infection of obturated root canals can be potentially prevented by enhancing the antibacterial activities of root canal obturation materials. We evaluated, in an in vitro model, the antimicrobial efficacy of silver ions added to a common endodontic sealer. For that purpose we performed growth inhibition studies and bacterial viability tests. We measured the zone of inhibition, optical density and performed confocal laser scanning microscopy. Our results show that the silver ions enhance the antimicrobial activity of the root canal sealer against Streptococcus mutans. This study approach may hold promise for studying other biologically based therapies and therefore increasing the success rate of routine orthograde root canal treatment.
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Affiliation(s)
- J Kreth
- UMN School of Dentistry, Minneapolis, MN 55455
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Qi F, Kreth J, Lévesque CM, Kay O, Mair RW, Shi W, Cvitkovitch DG, Goodman SD. Peptide pheromone induced cell death of Streptococcus mutans. FEMS Microbiol Lett 2006; 251:321-6. [PMID: 16165324 DOI: 10.1016/j.femsle.2005.08.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 08/11/2005] [Accepted: 08/12/2005] [Indexed: 12/14/2022] Open
Abstract
Streptococcus mutans is considered one of the main causative agents of human dental caries. Cell-cell communication through two-component signal transduction systems (TCSTS) plays an important role in the pathogenesis of S. mutans. One of the S. mutans TCSTS, ComDE, controls both competence development and biofilm formation. In this study, we showed that addition of exogenous competence-stimulating peptide (CSP) beyond the levels necessary for competence inhibited the growth of S. mutans in a ComDE-dependent manner. We also demonstrated that further increases of CSP stopped S. mutans cell division leading to cell death. Use of CSP as a possible therapeutic agent is discussed.
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Affiliation(s)
- Fengxia Qi
- Division of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, United States
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Kreth J, Hagerman E, Tam K, Merritt J, Wong DTW, Wu BM, Myung NV, Shi W, Qi F. Quantitative analyses of Streptococcus mutans biofilms with quartz crystal microbalance, microjet impingement and confocal microscopy. ACTA ACUST UNITED AC 2005; 1:277-284. [PMID: 16429589 PMCID: PMC1307168 DOI: 10.1017/s1479050504001516] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Microbial biofilm formation can be influenced by many physiological and genetic factors. The conventional microtiter plate assay provides useful but limited information about biofilm formation. With the fast expansion of the biofilm research field, there are urgent needs for more informative techniques to quantify the major parameters of a biofilm, such as adhesive strength and total biomass. It would be even more ideal if these measurements could be conducted in a real-time, non-invasive manner. In this study, we used quartz crystal microbalance (QCM) and microjet impingement (MJI) to measure total biomass and adhesive strength, respectively, of S. mutans biofilms formed under different sucrose concentrations. In conjunction with confocal laser scanning microscopy (CLSM) and the COMSTAT software, we show that sucrose concentration affects the biofilm strength, total biomass, and architecture in both qualitative and quantitative manners. Our data correlate well with previous observations about the effect of sucrose on the adherence of S. mutans to the tooth surface, and demonstrate that QCM is a useful tool for studying the kinetics of biofilm formation in real time and that MJI is a sensitive, easy-to-use device to measure the adhesive strength of a biofilm.
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Affiliation(s)
- J. Kreth
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - E. Hagerman
- Department of Bioengineering, UCLA School of Engineering and Applied Sciences, Los Angeles, CA 90095, USA
| | - K. Tam
- Department of Chemical and Environmental Engineering. University of California, Riverside, CA 92521, USA
| | - J. Merritt
- UCLA Molecular Biology Institute, Los Angeles, CA 90025, USA
| | - D. T. W. Wong
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - B. M. Wu
- Department of Bioengineering, UCLA School of Engineering and Applied Sciences, Los Angeles, CA 90095, USA
- Department of Materials Science and Engineering, UCLA School of Engineering and Applied Sciences, Los Angeles, CA 90095, USA
| | - N. V. Myung
- Department of Chemical and Environmental Engineering. University of California, Riverside, CA 92521, USA
| | - W. Shi
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, USA
- UCLA Molecular Biology Institute, Los Angeles, CA 90025, USA
| | - F. Qi
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, USA
- * Corresponding author: Dr F. Qi, Department of Oral Biology and Medicine, UCLA School of Dentistry, PO Box 951668, Los Angeles, CA 90095-1668, USA, T 1 310 825-0203, F 1 310 794-7109, E
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16
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Kreth J, Merritt J, Bordador C, Shi W, Qi F. Transcriptional analysis of mutacin I (mutA) gene expression in planktonic and biofilm cells of Streptococcus mutans using fluorescent protein and glucuronidase reporters. Oral Microbiol Immunol 2004; 19:252-6. [PMID: 15209996 DOI: 10.1111/j.1399-302x.2004.00148.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Streptococcus mutans is implicated as the primary pathogen involved in the development of dental caries. The production of specific bacteriocins (called mutacins) by S. mutans is one of the major virulence factors which facilitate the dominance of the bacterium within dental plaque. While much has been revealed about the biochemical structures of mutacins, little is known about the expression and regulation of mutacin genes, largely due to the lack of proper methods to monitor mutacin gene expression, especially under biofilm conditions. In this study, a set of reporter systems with the green fluorescent protein (gfp), the monomeric red fluorescent protein (mrfp1), and the glucuronidase (gusA) are introduced to S. mutans to study the transcriptional activities of the mutacin I gene (mutA). Although the mutA-reporter fusions are in single copy on the chromosome, these reporter systems display strong signals that allow us to effectively monitor mutA gene expression in S. mutans. Using these reporter systems, we show that mutA is expressed in both planktonic and biofilm cells, even though mutacin activities are normally detected only in biofilm cells. Furthermore, we confirm that mutR, the gene upstream of the mutacin operon, is required for mutacin I gene expression. The success of this study validates the feasibility of using these reporter systems to study gene expression and regulation in S. mutans.
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Affiliation(s)
- J Kreth
- Department of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, California 90095, USA
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Kim BH, Andersen C, Kreth J, Ulmke C, Schmid K, Benz R. Site-directed mutagenesis within the central constriction site of ScrY (sucroseporin): effect on ion transport and comparison of maltooligosaccharide binding to LamB of Escherichia coli. J Membr Biol 2002; 187:239-53. [PMID: 12163981 DOI: 10.1007/s00232-001-0167-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2001] [Indexed: 11/30/2022]
Abstract
The 3-D structures of the maltooligosaccharide-specific LamB-channel of Escherichia coli (also called maltoporin) and sucrose-specific ScrY (sucroseporin) are known from X-ray crystallography. The central constriction of the channels formed by the external loop 3 is controlled by a number of different amino acids. The most prominent one of these, N192, D201 and F204, were replaced by site-directed mutagenesis into those of LamB, which, according to the 3-D model of both channels are localized at similar places. The ScrY single mutants ScrYN192R, ScrYD201Y and ScrYF204D and the ScrY triple mutant ScrY3113 (N192R + D201Y + F204D) were created together with the triple mutant ScrY3213, which lacks also amino acids 1 to 61 from the N-terminal end. The mutant proteins were purified to homogeneity and were reconstituted into lipid bilayer membranes. In these experiments, the single-channel conductance of the mutants in different salt solutions and the stability constants for binding of different maltooligosaccharides to the mutant channels was measured using titration experiments with carbohydrates. The carbohydrate-induced block of the channel function could also be used for the study of current noise through the different mutant ScrY-channels. The analysis of the power density spectra allowed the evaluation of the on- and off-rate constants (k1 and k-1) of carbohydrate-binding to the binding site inside the channels. The results suggest that both on- and off-rate constants were affected by the mutations. Most of them showed a substantial effect on carbohydrate binding kinetics. Nevertheless, single-channel conductance and carbohydrate binding of ScrY3113 mutant were still different from that of LamB, suggesting that not only the amino acids of the central constriction but also the general architecture of both channels have a substantial influence on channel properties.
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Affiliation(s)
- B-H Kim
- Lehrstuhl für Biotechnologie, Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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Ulmke C, Kreth J, Lengeler JW, Welte W, Schmid K. Site-directed mutagenesis of loop L3 of sucrose porin ScrY leads to changes in substrate selectivity. J Bacteriol 1999; 181:1920-3. [PMID: 10074088 PMCID: PMC93594 DOI: 10.1128/jb.181.6.1920-1923.1999] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The difference in substrate selectivity of the maltodextrin (LamB) and sucrose (ScrY) porins is attributed mainly to differences in loop L3, which is supposed to constrict the lumen of the pores. We show that even a single mutation (D201Y) in loop L3 leads to a narrowing of the substrate range of ScrY to that resembling LamB. In addition, we removed the putative N-terminal coiled-coil structure of ScrY and studied the effect of this deletion on sucrose transport.
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Affiliation(s)
- C Ulmke
- AG Genetik, FB Biologie/Chemie, Universität Osnabrück, D-49069 Osnabrück, Germany
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