1
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Loi VV, Busche T, Kuropka B, Müller S, Methling K, Lalk M, Kalinowski J, Antelmann H. Staphylococcus aureus adapts to the immunometabolite itaconic acid by inducing acid and oxidative stress responses including S-bacillithiolations and S-itaconations. Free Radic Biol Med 2023; 208:859-876. [PMID: 37793500 DOI: 10.1016/j.freeradbiomed.2023.09.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/21/2023] [Accepted: 09/26/2023] [Indexed: 10/06/2023]
Abstract
Staphylococcus aureus is a major pathogen, which has to defend against reactive oxygen and electrophilic species encountered during infections. Activated macrophages produce the immunometabolite itaconate as potent electrophile and antimicrobial upon pathogen infection. In this work, we used transcriptomics, metabolomics and shotgun redox proteomics to investigate the specific stress responses, metabolic changes and redox modifications caused by sublethal concentrations of itaconic acid in S. aureus. In the RNA-seq transcriptome, itaconic acid caused the induction of the GlnR, KdpDE, CidR, SigB, GraRS, PerR, CtsR and HrcA regulons and the urease-encoding operon, revealing an acid and oxidative stress response and impaired proteostasis. Neutralization using external urea as ammonium source improved the growth and decreased the expression of the glutamine synthetase-controlling GlnR regulon, indicating that S. aureus experienced ammonium starvation upon itaconic acid stress. In the extracellular metabolome, the amounts of acetate and formate were decreased, while secretion of pyruvate and the neutral product acetoin were strongly enhanced to avoid intracellular acidification. Exposure to itaconic acid affected the amino acid uptake and metabolism as revealed by the strong intracellular accumulation of lysine, threonine, histidine, aspartate, alanine, valine, leucine, isoleucine, cysteine and methionine. In the proteome, itaconic acid caused widespread S-bacillithiolation and S-itaconation of redox-sensitive antioxidant and metabolic enzymes, ribosomal proteins and translation factors in S. aureus, supporting its oxidative and electrophilic mode of action in S. aureus. In phenotype analyses, the catalase KatA, the low molecular weight thiol bacillithiol and the urease provided protection against itaconic acid-induced oxidative and acid stress in S. aureus. Altogether, our results revealed that under physiological infection conditions, such as in the acidic phagolysome, itaconic acid is a highly effective antimicrobial against multi-resistant S. aureus isolates, which acts as weak acid causing an acid, oxidative and electrophilic stress response, leading to S-bacillithiolation and itaconation.
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Affiliation(s)
- Vu Van Loi
- Freie Universität Berlin, Institute of Biology-Microbiology, D-14195, Berlin, Germany
| | - Tobias Busche
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, D-33615, Bielefeld, Germany
| | - Benno Kuropka
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, D-14195, Berlin, Germany
| | - Susanne Müller
- Freie Universität Berlin, Institute of Biology-Microbiology, D-14195, Berlin, Germany
| | - Karen Methling
- Department of Cellular Biochemistry and Metabolomics, University of Greifswald, 17487, Greifswald, Germany
| | - Michael Lalk
- Department of Cellular Biochemistry and Metabolomics, University of Greifswald, 17487, Greifswald, Germany
| | - Jörn Kalinowski
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, D-33615, Bielefeld, Germany
| | - Haike Antelmann
- Freie Universität Berlin, Institute of Biology-Microbiology, D-14195, Berlin, Germany.
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2
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He Y, Vasilev K, Zilm P. pH-Responsive Biomaterials for the Treatment of Dental Caries-A Focussed and Critical Review. Pharmaceutics 2023; 15:1837. [PMID: 37514024 PMCID: PMC10385394 DOI: 10.3390/pharmaceutics15071837] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/20/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
Dental caries is a common and costly multifactorial biofilm disease caused by cariogenic bacteria that ferment carbohydrates to lactic acid, demineralizing the inorganic component of teeth. Therefore, low pH (pH 4.5) is a characteristic signal of the localised carious environment, compared to a healthy oral pH range (6.8 to 7.4). The development of pH-responsive delivery systems that release antibacterial agents in response to low pH has gained attention as a targeted therapy for dental caries. Release is triggered by high levels of acidogenic species and their reduction may select for the establishment of health-associated biofilm communities. Moreover, drug efficacy can be amplified by the modification of the delivery system to target adhesion to the plaque biofilm to extend the retention time of antimicrobial agents in the oral cavity. In this review, recent developments of different pH-responsive nanocarriers and their biofilm targeting mechanisms are discussed. This review critically discusses the current state of the art and innovations in the development and use of smart delivery materials for dental caries treatment. The authors' views for the future of the field are also presented.
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Affiliation(s)
- Yanping He
- Adelaide Dental School, University of Adelaide, Adelaide, SA 5000, Australia
| | - Krasimir Vasilev
- College of Medicine and Public Health, Flinders University, Bedford Park, Adelaide, SA 5042, Australia
| | - Peter Zilm
- Adelaide Dental School, University of Adelaide, Adelaide, SA 5000, Australia
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3
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Baruch Y, Golberg K, Sun Q, Yew-Hoong Gin K, Marks RS, Kushmaro A. 3,3'-Diindolylmethane (DIM): A Potential Therapeutic Agent against Cariogenic Streptococcus mutans Biofilm. Antibiotics (Basel) 2023; 12:1017. [PMID: 37370336 DOI: 10.3390/antibiotics12061017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/22/2023] [Accepted: 05/30/2023] [Indexed: 06/29/2023] Open
Abstract
Indole, a metabolite of the amino acid tryptophan, has been proven to act as a signal molecule in bacteria, acting in different aspects of biofilm formation. The oral biofilm is a type of biofilm that has consequences for human health. It is a complex, three-dimensional structure that develops on the surface of teeth via the attachment of primary microbial colonizers. Many oral infections are caused by an imbalance occurring in the microorganisms naturally found in oral biofilms and are considered major public health concerns. In this study, we test the effect of a natural bis-indole, 3,3'-Diindolylmethane (DIM), in mitigating the pathogenicity of the oral biofilm inhabiting bacterium Streptococcus mutans, a bacterium that is considered to be a principal etiological agent in dental caries. Our study found that DIM was able to attenuate S. mutans biofilm formation by 92%. Additionally, treatment with DIM lowered extracellular polymeric substance (EPS) production and decreased its durability significantly under acidic conditions. Therefore, the anti-biofilm and anti-virulence properties of DIM against S. mutans bacteria in an "oral setting" provides evidence for its usefulness in reducing biofilm formation and potentially for caries attenuation.
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Affiliation(s)
- Yifat Baruch
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - Karina Golberg
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - Qun Sun
- Key Laboratory of Bio-Resources and Eco-Environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Karina Yew-Hoong Gin
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Robert S Marks
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel
- The Ilse Katz Center for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - Ariel Kushmaro
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel
- The Ilse Katz Center for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel
- School of Sustainability and Climate Change, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
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4
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McAnally BE, Smith MS, Wiegert JG, Palanisamy V, Chitlapilly Dass S, Poole RK. Characterization of boar semen microbiome and association with sperm quality parameters. J Anim Sci 2023; 101:skad243. [PMID: 37464945 PMCID: PMC10393202 DOI: 10.1093/jas/skad243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/13/2023] [Indexed: 07/20/2023] Open
Abstract
Elevated levels of bacteria within fresh extended boar semen are associated with decreased sperm longevity, therefore reducing the fertility of a semen dose. The objective of this study was to characterize the bacterial communities using 16S rRNA sequencing in freshly extended boar semen samples and relate the prevalence and diversity of the microbial population to sperm quality parameters 1) between studs, 2) between pooled and single-sire doses, and 3) over a 5-day period. Eight single-sire (n = 4 per stud) and eight pooled (n = 4 per stud) non-frozen extended semen doses were obtained from two boar studs (A and B). Pooled doses were the composite of the boar's ejaculates used in single-sire doses. Doses were subsampled for 5 d post-collection. Ten negative controls of each pooled dose (n = 2) and single-sire dose (n = 8) remained sealed until the last day. Microbiome analysis was achieved by examining the V4 hypervariable region of the 16S rRNA gene of flash-frozen samples. Two evaluators determined the average sperm motility and agglutination (0: no adhesion to 3: >50% adhesion) by averaging their estimates together at 10 random locations per slide. Stud A had greater sperm agglutination (1.6 vs. 1.0 ± 0.1; P < 0.01) than stud B. Sperm motility decreased over the 5-day period (P < 0.01) and tended (P = 0.09) to be greater in stud B than A (67.4% vs. 61.5% ± 0.02%). Compared with stud A, stud B had a greater relative abundance of Proteobacteria (60.0% vs. 47.2% ± 1.5%; P < 0.01) and a lower relative abundance of Firmicutes (22.5% vs. 31.9% ± 1.4%; P < 0.01). Moreover, stud A had a greater relative abundance of Bacteroidetes (6.3% vs. 5.3% ± 0.4%; P < 0.01) and Actinobacteria (11.5% vs. 10.1% ± 0.5%; P = 0.05) than stud B. Differences were found in alpha diversity for both Chao1 (P < 0.01) and Shannon (P < 0.01) diversity indexes among days 2, 3, 4, and 5 post-collection to day 1. For beta diversity, unweighted UniFrac metric on days 2, 3, 4, and 5 post-collection differed from those on day 1 (P < 0.01). There were significant correlations between sperm motility and relative abundance of Prevotella (r = -0.29), Ruminococcus (r = -0.24), and Bacteroides (r = -0.32). Additionally, there were significant correlations between sperm motility and Chao1 (r = -0.50) and Shannon's index (r = -0.36). These results demonstrate that differences in bacterial communities over time and between boar studs can be associated with variation in sperm quality.
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Affiliation(s)
- Brooke E McAnally
- Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA
| | - Molly S Smith
- Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA
| | - Jeffrey G Wiegert
- Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA
| | - Vignesh Palanisamy
- Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA
| | | | - Rebecca K Poole
- Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA
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Inactivation of a New Potassium Channel Increases Rifampicin Resistance and Induces Collateral Sensitivity to Hydrophilic Antibiotics in Mycobacterium smegmatis. Antibiotics (Basel) 2022; 11:antibiotics11040509. [PMID: 35453260 PMCID: PMC9025972 DOI: 10.3390/antibiotics11040509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/05/2022] [Accepted: 04/08/2022] [Indexed: 12/10/2022] Open
Abstract
Rifampicin is a critical first-line antibiotic for treating mycobacterial infections such as tuberculosis, one of the most serious infectious diseases worldwide. Rifampicin resistance in mycobacteria is mainly caused by mutations in the rpoB gene; however, some rifampicin-resistant strains showed no rpoB mutations. Therefore, alternative mechanisms must explain this resistance in mycobacteria. In this work, a library of 11,000 Mycobacterium smegmatis mc2 155 insertion mutants was explored to search and characterize new rifampicin-resistance determinants. A transposon insertion in the MSMEG_1945 gene modified the growth rate, pH homeostasis and membrane potential in M. smegmatis, producing rifampicin resistance and collateral susceptibility to other antitubercular drugs such as isoniazid, ethionamide and aminoglycosides. Our data suggest that the M. smegmatis MSMEG_1945 protein is an ion channel, dubbed MchK, essential for maintaining the cellular ionic balance and membrane potential, modulating susceptibility to antimycobacterial agents. The functions of this new gene point once again to potassium homeostasis impairment as a proxy to resistance to rifampicin. This study increases the known repertoire of mycobacterial ion channels involved in drug susceptibility/resistance to antimycobacterial drugs and suggests novel intervention opportunities, highlighting ion channels as druggable pathways.
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Li C, Qi C, Yang S, Li Z, Ren B, Li J, Zhou X, Cai H, Xu X, Peng X. F0F1-ATPase Contributes to the Fluoride Tolerance and Cariogenicity of Streptococcus mutans. Front Microbiol 2022; 12:777504. [PMID: 35173687 PMCID: PMC8841791 DOI: 10.3389/fmicb.2021.777504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/20/2021] [Indexed: 12/30/2022] Open
Abstract
The phenotypic traits of Streptococcus mutans, such as fluoride tolerance, are usually associated with genotypic alterations. The aim of this study was to identify adaptive mutations of S. mutans to gradient fluoride concentrations and possible relationships between the mutations and fluoride tolerance. We identified a highly resistant S. mutans strain (FR1000) with a novel single nucleotide polymorphism (SNP, −36G→T) in the promoter region of F0F1-ATPase gene cluster (SMU_1527-SMU_1534) resistant to 1,000 ppm fluoride using the whole-genome Illumina PE250 sequencing. Thus, a −36G→T F0F1-ATPase promoter mutation from the parental strain S. mutans UA159 was constructed and named UA159-T. qRT-PCR showed that the F0F1-ATPase gene expression of both FR1000 and UA159-T was up-regulated, and fluoride tolerance of UA159-T was significantly improved. Complementation of Dicyclohexylcarbodiimide (DCCD), a specific inhibitor of F0F1-ATPase, increased fluoride susceptibility of FR1000 and UA159-T. Intracellular fluoride concentrations of fluoride tolerance strains were higher compared to UA159 strain as demonstrated by 18F analysis. Further validation with rat caries models showed that UA159-T caused more severe caries lesions under fluoride exposure compared with its parental UA159 strain. Overall, the identified −36G→T mutation in the promoter region of F0F1-ATPase gene drastically contributed to the fluoride tolerance and enhanced cariogenicity of S. mutans. These findings provided new insights into the mechanism of microbial fluoride tolerance, and suggested F0F1-ATPase as a potential target for suppressing fluoride resistant strains.
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Affiliation(s)
- Cheng Li
- State Key Laboratory of Oral Diseases and 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
| | - Cai Qi
- State Key Laboratory of Oral Diseases and 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
| | - Sirui Yang
- State Key Laboratory of Oral Diseases and 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
| | - Zhengyi Li
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Biao Ren
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jiyao Li
- State Key Laboratory of Oral Diseases and 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
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases and 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
| | - Huawei Cai
- Laboratory of Nuclear Medicine, Department of Clinical Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Xin Xu
- State Key Laboratory of Oral Diseases and 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
- *Correspondence: Xin Xu,
| | - Xian Peng
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Xian Peng,
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7
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Tan GR, Hsu CYS, Zhang Y. pH-Responsive Hybrid Nanoparticles for Imaging Spatiotemporal pH Changes in Biofilm-Dentin Microenvironments. ACS APPLIED MATERIALS & INTERFACES 2021; 13:46247-46259. [PMID: 34570460 DOI: 10.1021/acsami.1c11162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Engineering highly sensitive nanomaterials to monitor spatiotemporal pH changes has rather broad applications in studying various biological systems. Intraoral/biofilm-tooth pH is the single parameter that has demonstrated accurate assessment of dental caries risk, reflecting the summative integrated outcome of the complicated interactions between three etiological factors, namely, microorganisms/biofilm, diet/carbohydrates, and tooth/saliva/host. However, there is little to no technology/system capable of accurately probing simultaneously both the micro-pH profiles in dentin tissues and acidogenic oral biofilms and examining the pathophysiologic acid attacks with high spatial/temporal resolution. Therefore, a highly sensitive pH-responsive hybrid nanoparticle (pH-NP) is developed and coupled with an ex vivo tooth-biofilm caries model to simulate and study the key cariogenic determinants/steps. The pH-NP emits two distinct fluorescences with mutually inversely proportional intensities that vary accordingly to the proximity pH and with a ratiometric output sensitivity of 13.4-fold across a broad clinically relevant pH range of 3.0-8.0. Using [H+], in addition to pH, to calculate the "area-under-curve" corroborates the "minimum-pH" in semiquantifying the demineralizing potential in each biofilm-dentin zones/depth. The data mechanistically elucidates a two-pronged cariogenic effect of a popular-acidic-sweet-drink, in inundating the biofilm/tooth-system with H+ ions from both the drink and the metabolic byproducts of the biofilm.
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Affiliation(s)
- Guang-Rong Tan
- Faculty of Dentistry, National University of Singapore, 9 Lower Kent Ridge Road, Singapore 119085, Singapore
| | - Chin-Ying Stephen Hsu
- Faculty of Dentistry, National University of Singapore, 9 Lower Kent Ridge Road, Singapore 119085, Singapore
| | - Yong Zhang
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117583, Singapore
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Yabuta Y, Sato Y, Miki A, Nagata R, Bito T, Ishihara A, Watanabe F. Lemon myrtle extract inhibits lactate production by Streptococcus mutans. Biosci Biotechnol Biochem 2021; 85:2185-2190. [PMID: 34410296 DOI: 10.1093/bbb/zbab147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/11/2021] [Indexed: 11/13/2022]
Abstract
Backhousia citriodora (lemon myrtle) extract has been found to inhibit glucansucrase activity, which plays an important role in biofilm formation by Streptococcus mutans. In addition to glucansucrase, various virulence factors in S. mutans are involved in the initiation of caries. Lactate produced by S. mutans demineralizes the tooth enamel. This study investigated whether lemon myrtle extract can inhibit S. mutans lactate production. Lemon myrtle extract reduced the glycolytic pH drop in S. mutans culture and inhibited lactate production by at least 46%. Ellagic acid, quercetin, hesperetin, and myricetin, major polyphenols in lemon myrtle, reduced the glycolytic pH drop and lactate production, but not lactate dehydrogenase activity. Furthermore, these polyphenols reduced the viable S. mutans cell count. Thus, lemon myrtle extracts may inhibit S. mutans-mediated acidification of the oral cavity, thereby preventing dental caries and tooth decay.
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Affiliation(s)
- Yukinori Yabuta
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Yui Sato
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Arisu Miki
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Ryuta Nagata
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Tomohiro Bito
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Atsushi Ishihara
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Fumio Watanabe
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
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Yuan L, Wu H, Wang B, Jia C, Liang D, Caiyin QGL, Qiao J. ComX improves acid tolerance by regulating the expression of late competence proteins in Lactococcus lactis F44. J Dairy Sci 2021; 104:9556-9569. [PMID: 34147226 DOI: 10.3168/jds.2021-20184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/07/2021] [Indexed: 12/22/2022]
Abstract
ComX can improve bacterial competence by modulating global gene expression. Although competence induction may also be a protective mechanism under stress, this has not been investigated in detail. Here, we demonstrated that ComX improved the acid tolerance and nisin yield of Lactococcus lactis, which is an important gram-positive bacterium increasingly used in modern biotechnological applications. We found that overexpression of comX could improve the survival rate up to 36.5% at pH 4.0, compared with only 5.4% and 1.1% with the wild-type and comX knockout strains, respectively. Moreover, quantitative real-time PCR results indicated that comX overexpression stimulated the expression of late competence genes synergistically with exposure to acid stress. Finally, electrophoretic mobility shift assay demonstrated the binding of purified ComX to the cin-box in the promoters of these genes. Taken together, our results reveal a regulation mechanism by which ComX and acid stress can synergistically modulate the expression of late competence genes to enhance cells' acid tolerance and nisin yield.
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Affiliation(s)
- Lin Yuan
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Department of Bioengineering, School of Food Science and Bioengineering, Tianjin Agricultural University, Tianjin 300072, P. R. China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, P. R. China
| | - Hao Wu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, P. R. China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, P. R. China
| | - Binbin Wang
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, P. R. China; School of Life Science, Shanxi Normal University, Linfen 41000, P. R. China
| | - Cuili Jia
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Dongmei Liang
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, P. R. China
| | - Qing-Ge-Le Caiyin
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Jianjun Qiao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, P. R. China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, P. R. China.
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Abstract
Potassium is an essential mineral nutrient required by all living cells for normal physiological function. Therefore, maintaining intracellular potassium homeostasis during bacterial infection is a requirement for the survival of both host and pathogen. However, pathogenic bacteria require potassium transport to fulfill nutritional and chemiosmotic requirements, and potassium has been shown to directly modulate virulence gene expression, antimicrobial resistance, and biofilm formation. Host cells also require potassium to maintain fundamental biological processes, such as renal function, muscle contraction, and neuronal transmission; however, potassium flux also contributes to critical immunological and antimicrobial processes, such as cytokine production and inflammasome activation. Here, we review the role and regulation of potassium transport and signaling during infection in both mammalian and bacterial cells and highlight the importance of potassium to the success and survival of each organism.
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Thymol, cardamom and Lactobacillus plantarum nanoparticles as a functional candy with high protection against Streptococcus mutans and tooth decay. Microb Pathog 2020; 148:104481. [DOI: 10.1016/j.micpath.2020.104481] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/01/2020] [Accepted: 09/03/2020] [Indexed: 11/23/2022]
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12
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Shen P, Fernando JR, Walker GD, Yuan Y, Reynolds C, Reynolds EC. Addition of CPP-ACP to yogurt inhibits enamel subsurface demineralization. J Dent 2020; 103:103506. [PMID: 33115668 DOI: 10.1016/j.jdent.2020.103506] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/28/2020] [Accepted: 10/15/2020] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES The aim of this study was to investigate the capacity of an approved food additive with anticariogenic properties, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), when added to a processed, sugar-containing yogurt with added lactic-acid bacteria (probiotics), to prevent demineralization of enamel subsurface lesions in vitro. METHODS Enamel subsurface demineralised lesions were created in thirty extracted human third molars. These were then exposed to artificial saliva (AS) with: 1) Danone yogurt alone; 2) Danone yogurt with 0.2 % w/w CPP-ACP; or 3) Danone yogurt with 0.5 % w/w CPP-ACP at 37 °C for two weeks. The yogurt/AS was replaced with fresh preparations each day. At the completion of each treatment the enamel slabs were embedded, sectioned and analyzed using transverse microradiography to measure changes in enamel lesion depths and subsurface mineral content. Yogurt samples were analysed for soluble calcium (Ca) and inorganic phosphate (Pi) levels and pH. RESULTS Yogurt alone demineralized enamel subsurface lesions to produce significantly larger lesions. However, the addition of 0.2 % CPP-ACP to the yogurt resulted in significant reduction in demineralization compared with yogurt alone (p < 0.0001). The addition of 0.5 % CPP-ACP to the yogurt produced a net remineralization effect with a significant increase in lesion mineral content (p < 0.0001). The addition of CPP-ACP resulted in a significant (p < 0.0001) dose-related increase in Ca, Pi and pH. CONCLUSIONS The addition of CPP-ACP to a commercial yogurt exhibited a dose related protective effect with 0.5 % CPP-ACP producing remineralization of existing enamel subsurface lesions under the in vitro experimental conditions. CLINICAL SIGNIfiCANCE: The results of this study suggest that some processed yogurts with added sugar could result in enamel demineralization when frequently consumed by individuals with poor oral hygiene. The addition of CPP-ACP to these yogurts may help prevent demineralization and promote enamel subsurface lesion remineralization, and therefore, make them safer for teeth.
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Affiliation(s)
- Peiyan Shen
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - James R Fernando
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Glenn D Walker
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Yi Yuan
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Coralie Reynolds
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Eric C Reynolds
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia.
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13
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Panwar H, Rokana N, Aparna SV, Kaur J, Singh A, Singh J, Singh KS, Chaudhary V, Puniya AK. Gastrointestinal stress as innate defence against microbial attack. J Appl Microbiol 2020; 130:1035-1061. [PMID: 32869386 DOI: 10.1111/jam.14836] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 08/09/2020] [Accepted: 08/21/2020] [Indexed: 12/13/2022]
Abstract
The human gastrointestinal (GI) tract has been bestowed with the most difficult task of protecting the underlying biological compartments from the resident commensal flora and the potential pathogens in transit through the GI tract. It has a unique environment in which several defence tactics are at play while maintaining homeostasis and health. The GI tract shows myriad number of environmental extremes, which includes pH variations, anaerobic conditions, nutrient limitations, elevated osmolarity etc., which puts a check to colonization and growth of nonfriendly microbial strains. The GI tract acts as a highly selective barrier/platform for ingested food and is the primary playground for balance between the resident and uninvited organisms. This review focuses on antimicrobial defense mechanisms of different sections of human GI tract. In addition, the protective mechanisms used by microbes to combat the human GI defence systems are also discussed. The ability to survive this innate defence mechanism determines the capability of probiotic or pathogen strains to confer health benefits or induce clinical events respectively.
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Affiliation(s)
- H Panwar
- Department of Dairy Microbiology, College of Dairy Science and Technology, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India
| | - N Rokana
- Department of Dairy Microbiology, College of Dairy Science and Technology, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India
| | - S V Aparna
- Department of Dairy Microbiology, College of Dairy Science and Technology, Kerala Veterinary and Animal Science University, Mannuthy, Thrissur, India
| | - J Kaur
- Department of Dairy Microbiology, College of Dairy Science and Technology, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India
| | - A Singh
- Department of Dairy Microbiology, College of Dairy Science and Technology, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India
| | - J Singh
- Department of Dairy Microbiology, College of Dairy Science and Technology, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India
| | - K S Singh
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - V Chaudhary
- Department of Microbiology, Punjab Agriculture University, Ludhiana, Punjab, India
| | - A K Puniya
- Dairy Microbiology Division, ICAR-National Dairy Research Institute, Karnal, Haryana, India
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14
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Antibacterial Effect of Caffeic Acid Phenethyl Ester on Cariogenic Bacteria and Streptococcus mutans Biofilms. Antimicrob Agents Chemother 2020; 64:AAC.00251-20. [PMID: 32540977 DOI: 10.1128/aac.00251-20] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/31/2020] [Indexed: 02/05/2023] Open
Abstract
Dental caries is the most common disease in the human mouth. Streptococcus mutans is the primary cariogenic bacterium. Propolis is a nontoxic natural product with a strong inhibitory effect on oral cariogenic bacteria. The polyphenol-rich extract from propolis inhibits S. mutans growth and biofilm formation, as well as the genes involved in virulence and adherence, through the inhibition of glucosyltransferases (GTF). However, because the chemical composition of propolis is highly variable and complex, the mechanism of its antimicrobial action and the active compound are controversial and not completely understood. Caffeic acid phenethyl ester (CAPE) is abundant in the polyphenolic compounds from propolis, and it has many pharmacological effects. In this study, we investigated the antibacterial effects of CAPE on common oral cariogenic bacteria (Streptococcus mutans, Streptococcus sobrinus, Actinomyces viscosus, and Lactobacillus acidophilus) and its effects on the biofilm-forming and cariogenic abilities of S. mutans CAPE shows remarkable antimicrobial activity against cariogenic bacteria. Moreover, CAPE also inhibits the formation of S. mutans biofilms and their metabolic activity in mature biofilms. Furthermore, CAPE can inhibit the key virulence factors of S. mutans associated with cariogenicity, including acid production, acid tolerance, and the bacterium's ability to produce extracellular polysaccharides (EPS), without affecting bacterial viability at subinhibitory levels. In conclusion, CAPE appears to be a new agent with anticariogenic potential, not only via inhibition of the growth of cariogenic bacteria.
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15
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Tsujii T, Kawada-Matsuo M, Migita H, Ohta K, Oogai Y, Yamasaki Y, Komatsuzawa H. Antibacterial activity of phellodendron bark against Streptococcus mutans. Microbiol Immunol 2020; 64:424-434. [PMID: 32196736 DOI: 10.1111/1348-0421.12787] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 01/01/2023]
Abstract
Streptococcus mutans is a major cause of tooth decay due to its promotion of biofilm formation and acid production. Several plant extracts have been reported to have multiple biological activities such as anti-inflammation and antibacterial effects. This study investigated the antibacterial activity of three plant extracts, phellodendron bark (PB), yucca, and black ginger, and found that PB had a stronger effect than the other extracts. Then, the minimum inhibitory concentration (MIC) of PB against 100 S. mutans strains was investigated. The MIC range of PB was 9.8-312.5 µg/mL. PB suppressed the growth kinetics of S. mutans in a dose-dependent manner, even at sub-MICs of PB. Then, we investigated the effect of PB on S. mutans virulence. The PB suppressed biofilm formation at high concentrations, although PB did not affect the expression of glucosyltransferase genes. Additionally, PB suppressed the decrease in pH from adding an excess of glucose. The expression of genes responsible for acid production was increased by the addition of excess glucose without PB, whereas their expression levels were not increased in the presence of 1× and 2× MIC of PB. Although PB showed a bacteriostatic effect on planktonic S. mutans cells, it was found that more than 2× MIC of PB showed a partial bactericidal effect on biofilm cells. In conclusion, PB not only showed antibacterial activity against S. mutans but also decreased the cariogenic activity in S. mutans.
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Affiliation(s)
- Toshiya Tsujii
- Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Miki Kawada-Matsuo
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Hirono Migita
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Kouji Ohta
- Department of Public Oral Health, Program of Oral Health Sciences, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Yuichi Oogai
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Youichi Yamasaki
- Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Hitoshi Komatsuzawa
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
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16
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Ahn SJ, Desai S, Blanco L, Lin M, Rice KC. Acetate and Potassium Modulate the Stationary-Phase Activation of lrgAB in Streptococcus mutans. Front Microbiol 2020; 11:401. [PMID: 32231651 PMCID: PMC7082836 DOI: 10.3389/fmicb.2020.00401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/26/2020] [Indexed: 12/28/2022] Open
Abstract
Fluctuating environments force bacteria to constantly adapt and optimize the uptake of substrates to maintain cellular and nutritional homeostasis. Our recent findings revealed that LrgAB functions as a pyruvate uptake system in Streptococcus mutans, and its activity is modulated in response to glucose and oxygen levels. Here, we show that the composition of the growth medium dramatically influences the magnitude and pattern of lrgAB activation. Specifically, tryptone (T) medium does not provide a preferred environment for stationary phase lrgAB activation, which is independent of external pyruvate concentration. The addition of pyruvate to T medium can elicit PlrgA activation during exponential growth, enabling the cell to utilize external pyruvate for improvement of cell growth. Through comparison of the medium composition and a series of GFP quantification assays for measurement of PlrgA activation, we found that acetate and potassium (K+) play important roles in eliciting PlrgA activation at stationary phase. Of note, supplementation of pooled human saliva to T medium induced lrgAB expression at stationary phase and in response to pyruvate, suggesting that LrgAB is likely functional in the oral cavity. High concentrations of acetate inhibit cell growth, while high concentrations of K+ negatively regulate lrgAB activation. qPCR analysis also revealed that growth in T medium (acetate/K+ limited) significantly affects the expression of genes related to the catabolic pathways of pyruvate, including the Pta/AckA pathway (acetate metabolism). Lastly, stationary phase lrgAB expression is not activated when S. mutans is cultured in T medium, even in a strain that overexpresses lytST. Taken together, these data suggest that lrgAB activation and pyruvate uptake in S. mutans are connected to acetate metabolism and potassium uptake systems, important for cellular and energy homeostasis. They also suggest that these factors need to be implemented when planning metabolic experiments and analyzing data in S. mutans studies that may be sensitive to stationary growth phase.
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Affiliation(s)
- Sang-Joon Ahn
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, United States
| | - Shailja Desai
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, United States
| | - Loraine Blanco
- Department of Biology, College of Liberal Arts and Sciences, University of Florida, Gainesville, FL, United States
| | - Min Lin
- Department of Chemistry, College of Liberal Arts and Sciences, University of Florida, Gainesville, FL, United States
| | - Kelly C Rice
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States
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17
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Yamashita T, Kawada-Matsuo M, Katsumata T, Watanabe A, Oogai Y, Nishitani Y, Miyawaki S, Komatsuzawa H. Antibacterial activity of disodium succinoyl glycyrrhetinate, a derivative of glycyrrhetinic acid against Streptococcus mutans. Microbiol Immunol 2019; 63:251-260. [PMID: 31166029 DOI: 10.1111/1348-0421.12717] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/09/2019] [Accepted: 05/23/2019] [Indexed: 11/28/2022]
Abstract
Streptococcus mutans is a cariogenic bacterium that localizes in the oral cavity. Glycyrrhetinic acid (GRA) is a major component of licorice extract. GRA and several derivatives, including disodium succinoyl glycyrrhetinate (GR-SU), are known to have anti-inflammatory effects in humans. In this study, the antimicrobial effect of GRA and its derivatives against the S. mutans UA159 strain were investigated. Minimum inhibitory concentrations (MICs) of GRA and GR-SU showed antibacterial activity against the S. mutans strain, whereas other tested derivatives did not. Because GR-SU is more soluble than GRA, GR-SU was used for further experiments. The antibacterial activity of GR-SU against 100 S. mutans strains was evaluated and it was found that all strains are susceptible to GR-SU, with MIC values below 256 µg/mL. A cell viability assay showed that GR-SU has a bacteriostatic effect on S. mutans cells. As to growth kinetics, sub-MICs of GR-SU inhibited growth. The effect of GR-SU on S. mutans virulence was then investigated. GR-SU at sub-MICs suppresses biofilm formation. Additionally, GR-SU greatly suppresses the pH drop caused by the addition of glucose and glucose-induced expression of the genes responsible for acid production (ldh and pykF) and tolerance (aguD and atpD). Additionally, expression of enolase, which is responsible for the carbohydrate phosphotransferase system, was not increased in the presence of GR-SU, indicating that GR-SU suppresses incorporation of sugars into S. mutans. In conclusion, GR-SU has antibacterial activity against S. mutans and also decreases S. mutans virulence.
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Affiliation(s)
- Takahito Yamashita
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Miki Kawada-Matsuo
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Tamaki Katsumata
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Atsuko Watanabe
- Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yuichi Oogai
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yoshihiro Nishitani
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Shouichi Miyawaki
- Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Hitoshi Komatsuzawa
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
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18
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Wu CY, He SJ, Mar K, Stephen Hsu CY, Hung SL. Inhibition of Streptococcus mutans by a commercial yogurt drink. J Dent Sci 2019; 14:198-205. [PMID: 31205608 PMCID: PMC6558303 DOI: 10.1016/j.jds.2018.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/02/2018] [Indexed: 12/01/2022] Open
Abstract
Background/Purpose Studies have been focused on using probiotics to prevent caries. The lactobacillus probiotic bacteria in Yakult® (LcY) has been shown to inhibit the growth or biofilm formation of Streptococcus mutans. However, sucrose in Yakult® raised concerns. The purpose of this study was to determine effects of Yakult® on the growth and adhesion of S. mutans. Materials and methods S. mutans was grown in serial diluted Yakult®, filtered Yakult® or 20% heated Yakult®. S. mutans was co-cultured with LcY in media with or without diluted filtered Yakult®, or in LcY grown in media with or without sugars. Colony forming units and pH values of bacterial cultures were determined. SYTO 9-stained adhered bacteria were observed. Results Yakult® inhibited the growth of S. mutans. Filtering or heating Yakult® reduced its inhibitory ability against S. mutans. The inhibitory effect of LcY against S. mutans was enhanced when cultured in the presence of 20% filtered Yakult®. LcY cultured in sucrose media for 24 h inhibited the growth of S. mutans, but this effect was less evident when LcY was grown for 48 h. LcY grown in glucose or lactose media similarly reduced S. mutans growth. Culturing S. mutans with LcY grown in sucrose or glucose media reduced bacterial adhesion. However, co-culturing S. mutans with LcY grown in the lactose media did not decrease bacterial adhesion. Conclusion Yakult® and its probiotic content may inhibit S. mutans growth and the effect may be moderated by the type of sugar added for LcY cultivation.
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Affiliation(s)
- Ching-Yi Wu
- Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan.,Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Ssu-Jung He
- Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Kwei Mar
- Department of Community Dentistry, Zhong-Xiao Branch, Taipei City Hospital, Taipei, Taiwan.,Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chin-Ying Stephen Hsu
- Department of Dentistry, Faculty of Dentistry, National University of Singapore, Singapore
| | - Shan-Ling Hung
- Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan.,Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Community Dentistry, Zhong-Xiao Branch, Taipei City Hospital, Taipei, Taiwan
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19
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Zeng L, Burne RA. Essential Roles of the sppRA Fructose-Phosphate Phosphohydrolase Operon in Carbohydrate Metabolism and Virulence Expression by Streptococcus mutans. J Bacteriol 2019; 201:e00586-18. [PMID: 30348833 PMCID: PMC6304665 DOI: 10.1128/jb.00586-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 10/16/2018] [Indexed: 11/20/2022] Open
Abstract
The dental caries pathogen Streptococcus mutans can ferment a variety of sugars to produce organic acids. Exposure of S. mutans to certain nonmetabolizable carbohydrates, such as xylitol, impairs growth and can cause cell death. Recently, the presence of a sugar-phosphate stress in S. mutans was demonstrated using a mutant lacking 1-phosphofructokinase (FruK) that accumulates fructose-1-phosphate (F-1-P). Here, we studied an operon in S. mutans, sppRA, which was highly expressed in the fruK mutant. Biochemical characterization of a recombinant SppA protein indicated that it possessed hexose-phosphate phosphohydrolase activity, with preferences for F-1-P and, to a lesser degree, fructose-6-phosphate (F-6-P). SppA activity was stimulated by Mg2+ and Mn2+ but inhibited by NaF. SppR, a DeoR family regulator, repressed the expression of the sppRA operon to minimum levels in the absence of the fructose-derived metabolite F-1-P and likely also F-6-P. The accumulation of F-1-P, as a result of growth on fructose, not only induced sppA expression, but it significantly altered biofilm maturation through increased cell lysis and enhanced extracellular DNA release. Constitutive expression of sppA, via a plasmid or by deleting sppR, greatly alleviated fructose-induced stress in a fruK mutant, enhanced resistance to xylitol, and reversed the effects of fructose on biofilm formation. Finally, by identifying three additional putative phosphatases that are capable of promoting sugar-phosphate tolerance, we show that S. mutans is capable of mounting a sugar-phosphate stress response by modulating the levels of certain glycolytic intermediates, functions that are interconnected with the ability of the organism to manifest key virulence behaviors.IMPORTANCEStreptococcus mutans is a major etiologic agent for dental caries, primarily due to its ability to form biofilms on the tooth surface and to convert carbohydrates into organic acids. We have discovered a two-gene operon in S. mutans that regulates fructose metabolism by controlling the levels of fructose-1-phosphate, a potential signaling compound that affects bacterial behaviors. With fructose becoming increasingly common and abundant in the human diet, we reveal the ways that fructose may alter bacterial development, stress tolerance, and microbial ecology in the oral cavity to promote oral diseases.
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Affiliation(s)
- Lin Zeng
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Robert A Burne
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
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20
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Dashper SG, Shen P, Sim CPC, Liu SW, Butler CA, Mitchell HL, D'Cruze T, Yuan Y, Hoffmann B, Walker GD, Catmull DV, Reynolds C, Reynolds EC. CPP-ACP Promotes SnF 2 Efficacy in a Polymicrobial Caries Model. J Dent Res 2018; 98:218-224. [PMID: 30392434 DOI: 10.1177/0022034518809088] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Dental caries is associated with plaque dysbiosis, leading to an increase in the proportions of acidogenic and aciduric bacteria at the expense of alkali-generating commensal species. Stannous fluoride (SnF2) slows the progression of caries by remineralization of early lesions but has also been suggested to inhibit glycolysis of aciduric bacteria. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) promotes fluoride remineralization by acting as a salivary biomimetic that releases bioavailable calcium and phosphate ions, and the peptide complex has also been suggested to modify plaque composition. We developed a polymicrobial biofilm model of caries using 6 bacterial species representative of supragingival plaque that were cultured on sound human enamel and pulsed with sucrose 4 times a day to produce a high cariogenic challenge. We used this model to explore the mechanisms of action of SnF2 and CPP-ACP. Bacterial species in the biofilms were enumerated with 16S rRNA gene sequence analyses, and mineral loss and lesion formation were determined in the enamel directly under the polymicrobial biofilms via transverse microradiography. The model tested the twice-daily addition of SnF2, CPP-ACP, or both. SnF2 treatment reduced demineralization by 50% and had a slight effect on the composition of the polymicrobial biofilm. CPP-ACP treatment caused a similar inhibition of enamel demineralization (50%), a decrease in Actinomyces naeslundii and Lactobacillus casei abundance, and an increase in Streptococcus sanguinis and Fusobacterium nucleatum abundance in the polymicrobial biofilm. A combination of SnF2 and CPP-ACP resulted in a greater suppression of the acidogenic and aciduric bacteria and a significant 72% inhibition of enamel demineralization.
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Affiliation(s)
- S G Dashper
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - P Shen
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - C P C Sim
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - S W Liu
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - C A Butler
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - H L Mitchell
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - T D'Cruze
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - Y Yuan
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - B Hoffmann
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - G D Walker
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - D V Catmull
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - C Reynolds
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - E C Reynolds
- 1 Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, University of Melbourne, Melbourne, Australia
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21
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Park SN, Lim YK, Choi MH, Cho E, Bang IS, Kim JM, Ahn SJ, Kook JK. Antimicrobial Mechanism of Oleanolic and Ursolic Acids on Streptococcus mutans UA159. Curr Microbiol 2018; 75:11-19. [PMID: 28852850 DOI: 10.1007/s00284-017-1344-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 08/17/2017] [Indexed: 11/26/2022]
Abstract
Triterpenoid saponin derivatives oleanolic acid (OA) and ursolic acid (UA), but not betulinic acid (BA), were previously found to have strong antimicrobial activity against Streptococcus mutans. OA and UA inhibited the transcription of genes related to peptidoglycan biosynthesis, thereby preventing bacterial growth. However, it is not clear whether this is the only pathway involved in the antimicrobial activity of these compounds against S. mutans. Therefore, we used quantitative real-time PCR (qPCR) and microarray analyses to examine the expression of genes related to essential metabolic pathways in S. mutans UA159 following incubation with OA, UA, or BA. An oligonucleotide array consisting of 5363 probes was designed to survey 1928 of the 1963 genes in the genome of S. mutans UA159. Genes that showed >2-fold changes in expression in response to the treatment conditions were annotated, and selected target genes involved in central metabolism were analyzed by qPCR. Microarray analysis confirmed that the gene expression patterns of the OA- and UA-treated cells differed from that of the BA-treated culture, indicating differences in the antimicrobial mechanism. In particular, the expression of pfk and pykF, coding for glycolysis regulatory proteins phosphofructokinase and pyruvate kinase, respectively, were significantly decreased in the OA and UA groups (P < 0.05), as were genes involved in fatty acid and amino acid synthesis. In addition, the microarray analysis confirmed previous qPCR results showing that peptidoglycan synthesis is down-regulated in the OA- and UA-treated groups. OA and UA also appear to decrease the generation of organic acids by S. mutans UA159, which would have an anticaries effect. Overall, these findings suggest that OA and UA affect multiple genes involved in the central metabolism of S. mutans, with inhibition of glycolysis, fatty acid synthesis, amino acid synthesis, and peptidoglycan synthesis, all contributing to their antimicrobial activity.
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Affiliation(s)
- Soon-Nang Park
- Korean Collection for Oral Microbiology and Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju, 61452, Republic of Korea
| | - Yun Kyong Lim
- Korean Collection for Oral Microbiology and Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju, 61452, Republic of Korea
| | - Mi-Hwa Choi
- Korean Collection for Oral Microbiology and Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju, 61452, Republic of Korea
| | - Eugene Cho
- Korean Collection for Oral Microbiology and Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju, 61452, Republic of Korea
| | - Iel Soo Bang
- Department of Oral Microbiology, School of Dentistry, Chosun University, Gwangju, 61452, Republic of Korea
- Oral Biology Research Institute, Chosun University, Gwangju, 61452, Republic of Korea
| | - Jung Min Kim
- Genoplan Korea, Inc. and NAR Center, Inc., Seoul, 06221, Republic of Korea
| | - Sug-Joon Ahn
- Dental Research Institute and Department of Orthodontics, School of Dentistry, Seoul National University, Seoul, 03080, Republic of Korea.
| | - Joong-Ki Kook
- Korean Collection for Oral Microbiology and Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju, 61452, Republic of Korea.
- Oral Biology Research Institute, Chosun University, Gwangju, 61452, Republic of Korea.
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22
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Byrne SJ, Butler CA, Reynolds EC, Dashper SG. Taxonomy of Oral Bacteria. METHODS IN MICROBIOLOGY 2018. [DOI: 10.1016/bs.mim.2018.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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23
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Katic V, Curkovic L, Bosnjak MU, Peros K, Mandic D, Spalj S. Effect of pH, fluoride and hydrofluoric acid concentration on ion release from NiTi wires with various coatings. Dent Mater J 2017; 36:149-156. [PMID: 28111387 DOI: 10.4012/dmj.2016-169] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aim was to determine effect of pH, fluoride (F-) and hydrofluoric acid concentration (HF) on dynamic of nickel (Ni2+) and titanium (Ti4+) ions release. Nickel-titanium wires with untreated surface (NiTi), rhodium (RhNiTi) and nitride (NNiTi) coating were immersed once a week for five min in remineralizing agents, followed by immersion to artificial saliva. Ion release was recorded after 3, 7, 14, 21 and 28 days. Pearson correlations and linear regression were used for statistical analysis. Release of Ni2+ from NiTi and NNiTi wires correlated highly linearly positively with HF (r=0.948 and 0.940, respectively); for RhNiTi the correlation was lower and negative (r=-0.605; p<0.05). The prediction of Ti4+ release was significant for NiTi (r=0.797) and NNiTi (r=0.788; p<0.05) wire. Association with F- was lower; for pH it was not significant. HF predicts the release of ions from the NiTi wires better than the pH and F- of the prophylactic agents.
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Affiliation(s)
- Visnja Katic
- Department of Orthodontics, Faculty of Medicine, University of Rijeka
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24
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Chamaecyparis obtusa Suppresses Virulence Genes in Streptococcus mutans. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:2396404. [PMID: 27293453 PMCID: PMC4879247 DOI: 10.1155/2016/2396404] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/14/2016] [Indexed: 02/07/2023]
Abstract
Chamaecyparis obtusa (C. obtusa) is known to have antimicrobial effects and has been used as a medicinal plant and in forest bathing. This study aimed to evaluate the anticariogenic activity of essential oil of C. obtusa on Streptococcus mutans, which is one of the most important bacterial causes of dental caries and dental biofilm formation. Essential oil from C. obtusa was extracted, and its effect on bacterial growth, acid production, and biofilm formation was evaluated. C. obtusa essential oil exhibited concentration-dependent inhibition of bacterial growth over 0.025 mg/mL, with 99% inhibition at a concentration of 0.2 mg/mL. The bacterial biofilm formation and acid production were also significantly inhibited at the concentration greater than 0.025 mg/mL. The result of LIVE/DEAD® BacLight™ Bacterial Viability Kit showed a concentration-dependent bactericidal effect on S. mutans and almost all bacteria were dead over 0.8 mg/mL. Real-time PCR analysis showed that gene expression of some virulence factors such as brpA, gbpB, gtfC, and gtfD was also inhibited. In GC and GC-MS analysis, the major components were found to be α-terpinene (40.60%), bornyl acetate (12.45%), α-pinene (11.38%), β-pinene (7.22%), β-phellandrene (3.45%), and α-terpinolene (3.40%). These results show that C. obtusa essential oil has anticariogenic effect on S. mutans.
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25
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Bezerra DS, Stipp RN, Neves BG, Guedes SFF, Nascimento MM, Rodrigues LKA. Insights into the Virulence Traits of Streptococcus mutans in Dentine Carious Lesions of Children with Early Childhood Caries. Caries Res 2016; 50:279-87. [PMID: 27160402 DOI: 10.1159/000445256] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/02/2016] [Indexed: 11/19/2022] Open
Abstract
Streptococcus mutans is an oral bacterium considered to play a major role in the development of dental caries. This study aimed to investigate the prevalence of S. mutans in active and arrested dentine carious lesions of children with early childhood caries and to examine the expression profile of selected S. mutans genes associated with survival and virulence, within the same carious lesions. Dentine samples were collected from 29 active and 16 arrested carious lesions that were diagnosed in preschool children aged 2-5 years. Total RNA was extracted from the dentine samples, and reverse transcription quantitative real-time PCR analyses were performed for the quantification of S. mutans and for analyses of the expression of S. mutans genes associated with bacterial survival (atpD, nox, pdhA) and virulence (fabM and aguD). There was no statistically significant difference in the prevalence of S. mutans between active and arrested carious lesions. Expression of the tested genes was detected in both types of carious dentine. The pdhA (p = 0.04) and aguD (p = 0.05) genes were expressed at higher levels in arrested as compared to active lesions. Our findings revealed that S. mutans is part of the viable microbial community in active and arrested dentine carious lesions. The increase in expression of the pdhA and aguD genes in arrested lesions is likely due to the unfavourable environmental conditions for microbial growth, inherent to this type of lesions.
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Affiliation(s)
- Daniela S Bezerra
- Postgraduation Program, Faculty of Pharmacy, Dentistry and Nursing, Federal University of Cearx00E1;, Fortaleza, Brazil
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26
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Byrne SJ, Tan KH, Dashper SG, Shen P, Stanton DP, Yuan Y, Reynolds EC. The potential acidogenicity of liquid breakfasts. J Dent 2016; 49:33-9. [PMID: 27109215 DOI: 10.1016/j.jdent.2016.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 04/17/2016] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES To determine the potential acidogenicy of liquid breakfasts. METHODS In vitro acid production by Streptococcus mutans was measured in the beverages at a pH of 5.5, as was the fall in pH over 10min. The buffering capacity was determined, as well as the calcium, inorganic phosphate and fluoride concentrations (total and soluble) of the beverages. Bovine milk (UHT) was used for comparison. RESULTS The rate of acid production by S. mutans, and pH fall over 10min was greater in liquid breakfasts compared to bovine milk. All beverages except one demonstrated a significantly lower buffering capacity than bovine milk. All beverages contained significantly greater concentrations of soluble calcium than bovine milk, and all except two contained significantly more soluble inorganic phosphate. CONCLUSIONS S. mutans was able to generate significantly more acid in the liquid breakfasts than in bovine milk, indicating these drinks may contribute to a cariogenic diet. In general, the liquid breakfasts required significantly less acid than bovine milk to reduce their pH to the approximate critical pH for enamel demineralisation. However, the liquid breakfasts also tended to contain significantly more soluble calcium and inorganic phosphate than bovine milk. CLINICAL SIGNIFICANCE The substantial amounts and various types of sugars found within liquid breakfast beverages may result in a significant pH drop in dental plaque following consumption of these products.
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Affiliation(s)
- Samantha J Byrne
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Kheng H Tan
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Stuart G Dashper
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Peiyan Shen
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - David P Stanton
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Yi Yuan
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Eric C Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia.
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27
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De A, Lupidi G, Petrelli D, Vitali LA. Molecular cloning and biochemical characterization of Xaa-Pro dipeptidyl-peptidase from Streptococcus mutans and its inhibition by anti-human DPP IV drugs. FEMS Microbiol Lett 2016; 363:fnw066. [PMID: 27010012 DOI: 10.1093/femsle/fnw066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2016] [Indexed: 11/13/2022] Open
Abstract
Streptococcus mutans harbours an intracellular, human DPP IV-analogous enzyme Xaa-Pro dipeptidyl-peptidase (EC 3.4.14.11). According to previous reports, an extracellular isozyme in S. gordonii and S. suis has been associated with virulence. Speculating that even an intracellular form may aid in virulence of S. mutans, we have tried to purify, characterize and evaluate enzyme inhibition by specific inhibitors. The native enzyme was partially purified by ion-exchange and gel filtration chromatography. Owing to low yield, the enzyme was overexpressed in Lactococcus lactis and purified by affinity chromatography. The recombinant enzyme (rSm-XPDAP) had a specific activity of 1070 U mg(-1), while the Vmax and Km were 7 μM min(-1) and 89 ± 7 μM (n = 3), respectively. The serine protease inhibitor phenylmethylsulphonyl fluoride and a DPP IV-specific inhibitor diprotin A proved to be active against rSm-XPDAP. As a novel approach, the evaluation of the effect of anti-human DPP IV (AHD) drugs on rSm-XPDAP activity found saxagliptin to be effective to some extent (Ki = 129 ± 16 μM), which may lead to the synthesis and development of a new class of antimicrobial agents.
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Affiliation(s)
- Arpan De
- School of Pharmacy, University of Camerino, Camerino, Italy
| | - Giulio Lupidi
- School of Pharmacy, University of Camerino, Camerino, Italy
| | - Dezemona Petrelli
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Luca A Vitali
- School of Pharmacy, University of Camerino, Camerino, Italy
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28
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Binepal G, Gill K, Crowley P, Cordova M, Brady LJ, Senadheera DB, Cvitkovitch DG. Trk2 Potassium Transport System in Streptococcus mutans and Its Role in Potassium Homeostasis, Biofilm Formation, and Stress Tolerance. J Bacteriol 2016; 198:1087-100. [PMID: 26811321 PMCID: PMC4800877 DOI: 10.1128/jb.00813-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/13/2016] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED Potassium (K(+)) is the most abundant cation in the fluids of dental biofilm. The biochemical and biophysical functions of K(+) and a variety of K(+) transport systems have been studied for most pathogenic bacteria but not for oral pathogens. In this study, we establish the modes of K(+) acquisition in Streptococcus mutans and the importance of K(+) homeostasis for its virulence attributes. The S. mutans genome harbors four putative K(+) transport systems that included two Trk-like transporters (designated Trk1 and Trk2), one glutamate/K(+) cotransporter (GlnQHMP), and a channel-like K(+) transport system (Kch). Mutants lacking Trk2 had significantly impaired growth, acidogenicity, aciduricity, and biofilm formation. [K(+)] less than 5 mM eliminated biofilm formation in S. mutans. The functionality of the Trk2 system was confirmed by complementing an Escherichia coli TK2420 mutant strain, which resulted in significant K(+) accumulation, improved growth, and survival under stress. Taken together, these results suggest that Trk2 is the main facet of the K(+)-dependent cellular response of S. mutans to environment stresses. IMPORTANCE Biofilm formation and stress tolerance are important virulence properties of caries-causing Streptococcus mutans. To limit these properties of this bacterium, it is imperative to understand its survival mechanisms. Potassium is the most abundant cation in dental plaque, the natural environment of S. mutans. K(+) is known to function in stress tolerance, and bacteria have specialized mechanisms for its uptake. However, there are no reports to identify or characterize specific K(+) transporters in S. mutans. We identified the most important system for K(+) homeostasis and its role in the biofilm formation, stress tolerance, and growth. We also show the requirement of environmental K(+) for the activity of biofilm-forming enzymes, which explains why such high levels of K(+) would favor biofilm formation.
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Affiliation(s)
- Gursonika Binepal
- Department of Microbiology, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Kamal Gill
- Department of Microbiology, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Paula Crowley
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Martha Cordova
- Department of Microbiology, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - L Jeannine Brady
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Dilani B Senadheera
- Department of Microbiology, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Dennis G Cvitkovitch
- Department of Microbiology, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
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29
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The well-coordinated linkage between acidogenicity and aciduricity via insoluble glucans on the surface of Streptococcus mutans. Sci Rep 2015; 5:18015. [PMID: 26657939 PMCID: PMC4675080 DOI: 10.1038/srep18015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/10/2015] [Indexed: 11/25/2022] Open
Abstract
Streptococcus mutans is considered the principal cariogenic bacterium for dental caries. Despite the recognition of their importance for cariogenesis, the possible coordination among S. mutans’ main virulence factors, including glucan production, acidogenicity and aciduricity, has been less well studied. In the present study, using S. mutans strains with surface-displayed pH-sensitive pHluorin, we revealed sucrose availability- and Gtf functionality-dependent proton accumulation on S. mutans surface. Consistent with this, using a pH-sensitive dye, we demonstrated that both in vivo cell-produced and in vitro enzymatically synthesized insoluble glucans displayed proton-concentrating ability. Global transcriptomics revealed proton accumulation triggers the up-regulation of genes encoding functions involved in acid tolerance response in a glucan-dependent manner. Our data suggested that this proton enrichment around S. mutans could pre-condition the bacterium for acid-stress. Consistent with this hypothesis, we found S. mutans strains defective in glucan production were more acid sensitive. Our study revealed for the first time that insoluble glucans is likely an essential factor linking acidogenicity with aciduricity. The coordination of these key virulence factors could provide new insights on how S. mutans may have become a major cariogenic pathogen.
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30
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Baker JL, Abranches J, Faustoferri RC, Hubbard CJ, Lemos JA, Courtney MA, Quivey R. Transcriptional profile of glucose-shocked and acid-adapted strains of Streptococcus mutans. Mol Oral Microbiol 2015; 30:496-517. [PMID: 26042838 DOI: 10.1111/omi.12110] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2015] [Indexed: 01/10/2023]
Abstract
The aciduricity of Streptococcus mutans is an important virulence factor of the organism, required to both out-compete commensal oral microorganisms and cause dental caries. In this study, we monitored transcriptional changes that occurred as a continuous culture of either an acid-tolerant strain (UA159) or an acid-sensitive strain (fabM::Erm) moved from steady-state growth at neutral pH, experienced glucose-shock and acidification of the culture, and transitioned to steady-state growth at low pH. Hence, the timing of elements of the acid tolerance response (ATR) could be observed and categorized as acute vs. adaptive ATR mechanisms. Modulation of branched chain amino acid biosynthesis, DNA/protein repair mechanisms, reactive oxygen species metabolizers and phosphoenolpyruvate:phosphotransferase systems occurred in the initial acute phase, immediately following glucose-shock, while upregulation of F1 F0 -ATPase did not occur until the adaptive phase, after steady-state growth had been re-established. In addition to the archetypal ATR pathways mentioned above, glucose-shock led to differential expression of genes suggesting a re-routing of resources away from the synthesis of fatty acids and proteins, and towards synthesis of purines, pyrimidines and amino acids. These adjustments were largely transient, as upon establishment of steady-state growth at acidic pH, transcripts returned to basal expression levels. During growth at steady-state pH 7, fabM::Erm had a transcriptional profile analogous to that of UA159 during glucose-shock, indicating that even during growth in rich media at neutral pH, the cells were stressed. These results, coupled with a recently established collection of deletion strains, provide a starting point for elucidation of the acid tolerance response in S. mutans.
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Affiliation(s)
- J L Baker
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - J Abranches
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.,Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - R C Faustoferri
- Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - C J Hubbard
- Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - J A Lemos
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.,Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - M A Courtney
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - R Quivey
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.,Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
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31
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Sharply Tuned pH Response of Genetic Competence Regulation in Streptococcus mutans: a Microfluidic Study of the Environmental Sensitivity of comX. Appl Environ Microbiol 2015; 81:5622-31. [PMID: 26070670 DOI: 10.1128/aem.01421-15] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 05/29/2015] [Indexed: 12/21/2022] Open
Abstract
Genetic competence in Streptococcus mutans is a transient state that is regulated in response to multiple environmental inputs. These include extracellular pH and the concentrations of two secreted peptides, designated CSP (competence-stimulating peptide) and XIP (comX-inducing peptide). The role of environmental cues in regulating competence can be difficult to disentangle from the effects of the organism's physiological state and its chemical modification of its environment. We used microfluidics to control the extracellular environment and study the activation of the key competence gene comX. We find that the comX promoter (PcomX) responds to XIP or CSP only when the extracellular pH lies within a narrow window, about 1 pH unit wide, near pH 7. Within this pH range, CSP elicits a strong PcomX response from a subpopulation of cells, whereas outside this range the proportion of cells expressing comX declines sharply. Likewise, PcomX is most sensitive to XIP only within a narrow pH window. While previous work suggested that comX may become refractory to CSP or XIP stimulus as cells exit early exponential phase, our microfluidic data show that extracellular pH dominates in determining sensitivity to XIP and CSP. The data are most consistent with an effect of pH on the ComR/ComS system, which has direct control over transcription of comX in S. mutans.
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32
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Heunis T, Deane S, Smit S, Dicks LMT. Proteomic Profiling of the Acid Stress Response in Lactobacillus plantarum 423. J Proteome Res 2014; 13:4028-39. [DOI: 10.1021/pr500353x] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Tiaan Heunis
- Department
of Microbiology, Stellenbosch University, Private Bag X1, 7602 Matieland, South Africa
| | - Shelly Deane
- Department
of Microbiology, Stellenbosch University, Private Bag X1, 7602 Matieland, South Africa
| | - Salome Smit
- Division
of Molecular Biology and Human Genetics, Stellenbosch University, Francie van Zijl Drive, Tygerberg 7505, South Africa
- MS Unit,
Proteomics lab, Central Analytical Facility, Stellenbosch University, Private Bag X1, 7602 Matieland, South Africa
| | - Leon M. T. Dicks
- Department
of Microbiology, Stellenbosch University, Private Bag X1, 7602 Matieland, South Africa
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33
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Buckley AA, Faustoferri RC, Quivey RG. β-Phosphoglucomutase contributes to aciduricity in Streptococcus mutans. MICROBIOLOGY-SGM 2014; 160:818-827. [PMID: 24509501 DOI: 10.1099/mic.0.075754-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Streptococcus mutans encounters an array of sugar moieties within the oral cavity due to a varied human diet. One such sugar is β-d-glucose 1-phosphate (βDG1P), which must be converted to glucose 6-phosphate (G6P) before further metabolism to lactic acid. The conversion of βDG1P to G6P is mediated by β-phosphoglucomutase, which has not been previously observed in any oral streptococci, but has been extensively characterized and the gene designated pgmB in Lactococcus lactis. An orthologue was identified in S. mutans, SMU.1747c, and deletion of the gene resulted in the inability of the deletion strain to convert βDG1P to G6P, indicating that SMU.1747c is a β-phosphoglucomutase and should be designated pgmB. In this study, we sought to characterize how deletion of pgmB affected known virulence factors of S. mutans, specifically acid tolerance. The ΔpgmB strain showed a decreased ability to survive acid challenge. Additionally, the strain lacking β-phosphoglucomutase had a diminished glycolytic profile compared with the parental strain. Deletion of pgmB had a negative impact on the virulence of S. mutans in the Galleria mellonella (greater wax worm) animal model. Our results indicate that pgmB plays a role at the juncture of carbohydrate metabolism and virulence.
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Affiliation(s)
- Andrew A Buckley
- Department of Microbiology & Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Roberta C Faustoferri
- Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Robert G Quivey
- Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.,Department of Microbiology & Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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34
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da Silva ACB, da Silva DR, Macêdo Ferreira SAD, Agripino GG, Albuquerque AR, Rêgo TGD. <i>In Silico</i> Approach for the Identification of Potential Targets and Specific Antimicrobials for <i>Streptococcus mutans</i>. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/abb.2014.54045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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35
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Dreyer J, Zhang C, Ippoliti E, Carloni P. Role of the Membrane Dipole Potential for Proton Transport in Gramicidin A Embedded in a DMPC Bilayer. J Chem Theory Comput 2013; 9:3826-31. [PMID: 26584128 DOI: 10.1021/ct400374n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The membrane potential at the water/phospholipid interfaces may play a key role for proton conduction of gramicidin A (gA). Here we address this issue by Density Functional Theory-based molecular dynamics and metadynamics simulations. The calculations, performed on gA embedded in a solvated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) model membrane environment (about 2,000 atoms), indicate that (i) the membrane dipole potential rises at the channel mouth by ∼0.4 V. A similar value has been measured for gA embedded in a DMPC monolayer; (ii) the calculated free energy barrier is located at the channel entrance, consistent with experiments comparing gA proton conduction in different bilayers. The electronic structures of the proton ligands (water molecules and peptide units) are similar to those in the bulk solvent. Based on these results, we suggest an important role of the membrane dipole potential for the free energy barrier of proton permeation of gA. This may provide a rationale for the large increase in the rate of proton conduction under application of a transmembrane voltage, as observed experimentally. Our calculations might suggest also a role for proton desolvation for the permeation process. This role has already emerged from EVB calculations on gA embedded in a model membrane.
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Affiliation(s)
- Jens Dreyer
- Computational Biophysics, German Research School for Simulation Sciences, Joint venture of RWTH Aachen University and Forschungszentrum Jülich , Germany, D-52425 Jülich, Germany.,IAS-5, Computational Biomedicine, Institute for Advanced Simulation , Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Chao Zhang
- Computational Biophysics, German Research School for Simulation Sciences, Joint venture of RWTH Aachen University and Forschungszentrum Jülich , Germany, D-52425 Jülich, Germany.,IAS-5, Computational Biomedicine, Institute for Advanced Simulation , Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Emiliano Ippoliti
- Computational Biophysics, German Research School for Simulation Sciences, Joint venture of RWTH Aachen University and Forschungszentrum Jülich , Germany, D-52425 Jülich, Germany.,IAS-5, Computational Biomedicine, Institute for Advanced Simulation , Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Paolo Carloni
- Computational Biophysics, German Research School for Simulation Sciences, Joint venture of RWTH Aachen University and Forschungszentrum Jülich , Germany, D-52425 Jülich, Germany.,IAS-5, Computational Biomedicine, Institute for Advanced Simulation , Forschungszentrum Jülich, D-52425 Jülich, Germany
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36
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Mathematical modelling of tooth demineralisation and pH profiles in dental plaque. J Theor Biol 2012; 309:159-75. [DOI: 10.1016/j.jtbi.2012.05.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 05/22/2012] [Accepted: 05/22/2012] [Indexed: 11/20/2022]
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37
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Dashper S, Saion B, Stacey M, Manton D, Cochrane N, Stanton D, Yuan Y, Reynolds E. Acidogenic potential of soy and bovine milk beverages. J Dent 2012; 40:736-41. [DOI: 10.1016/j.jdent.2012.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 05/07/2012] [Accepted: 05/10/2012] [Indexed: 11/24/2022] Open
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38
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The branched-chain amino acid aminotransferase encoded by ilvE is involved in acid tolerance in Streptococcus mutans. J Bacteriol 2012; 194:2010-9. [PMID: 22328677 DOI: 10.1128/jb.06737-11] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability of Streptococcus mutans to produce and tolerate organic acids from carbohydrate metabolism represents a major virulence factor responsible for the formation of carious lesions. Pyruvate is a key metabolic intermediate that, when rerouted to other metabolic pathways such as amino acid biosynthesis, results in the alleviation of acid stress by reducing acid end products and aiding in maintenance of intracellular pH. Amino acid biosynthetic genes such as ilvC and ilvE were identified as being upregulated in a proteome analysis of Streptococcus mutans under acid stress conditions (A. C. Len, D. W. Harty, and N. A. Jacques, Microbiology 150:1353-1366, 2004). In Lactococcus lactis and Staphylococcus carnosus, the ilvE gene product is involved with biosynthesis and degradation of branched-chain amino acids, as well as in the production of branched-chain fatty acids (B. Ganesan and B. C. Weimer, Appl. Environ. Microbiol. 70:638-641, 2004; S. M. Madsen et al., Appl. Environ. Microbiol. 68:4007-4014, 2002; and M. Yvon, S. Thirouin, L. Rijnen, D. Fromentier, and J. C. Gripon, Appl. Environ. Microbiol. 63:414-419, 1997). Here we constructed and characterized an ilvE deletion mutant of S. mutans UA159. Growth experiments revealed that the ilvE mutant strain has a lag in growth when nutritionally limited for branched-chain amino acids. We further demonstrated that the loss of ilvE causes a decrease in acid tolerance. The ilvE strain exhibits a defect in F(1)-F(o) ATPase activity and has reduced catabolic activity for isoleucine and valine. Results from transcriptional studies showed that the ilvE promoter is upregulated during growth at low pH. Collectively, the results of this investigation show that amino acid metabolism is a component of the acid-adaptive repertoire of S. mutans.
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Effects of compounds found in Nidus Vespae on the growth and cariogenic virulence factors of Streptococcus mutans. Microbiol Res 2012; 167:61-8. [DOI: 10.1016/j.micres.2011.03.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 03/16/2011] [Accepted: 03/26/2011] [Indexed: 12/26/2022]
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The tea catechin epigallocatechin gallate suppresses cariogenic virulence factors of Streptococcus mutans. Antimicrob Agents Chemother 2010; 55:1229-36. [PMID: 21149622 DOI: 10.1128/aac.01016-10] [Citation(s) in RCA: 210] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Streptococcus mutans, the primary etiologic agent of dental caries, possesses a series of virulence factors associated with its cariogenicity. Alternatives to traditional antimicrobial treatment, agents selectively inhibiting the virulence factors without necessarily suppressing the resident oral species, are promising. The anticariogenic properties of tea have been suggested in experimental animals and humans. Tea polyphenols, especially epigallocatechin gallate (EGCg), have been shown to inhibit the growth and glucosyltransferases activity of S. mutans. However, their effects on biofilm and cariogenic virulence factors of oral streptococci other than glucosyltransferases have not been well documented. In this study, we investigated the biological effect of EGCg on the virulence factors of S. mutans associated with its acidogenicity and acidurity. The antimicrobial effects of EGCg on S. mutans biofilm grown in chemically defined medium were also examined. EGCg inhibited growth of S. mutans planktonic cells at an MIC of 31.25 μg/ml and a minimal bactericidal concentration (MBC) of 62.5 μg/ml. EGCg also inhibited S. mutans biofilm formation at 15.6 μg/ml (minimum concentration that showed at least 90% inhibition of biofilm formation) and reduced viability of the preformed biofilm at 625 μg/ml (sessile MIC₈₀). EGCg at sub-MIC levels inhibited acidogenicity and acidurity of S. mutans cells. Analysis of the data obtained from real-time PCR showed that EGCg significantly suppressed the ldh, eno, atpD, and aguD genes of S. mutans UA159. Inhibition of the enzymatic activity of F₁F₀-ATPase and lactate dehydrogenase was also noted (50% inhibitory concentration between 15.6 and 31.25 μg/ml). These findings suggest that EGCg is a natural anticariogenic agent in that it exhibits antimicrobial activity against S. mutans and suppresses the specific virulence factors associated with its cariogenicity.
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Abstract
Since its discovery in 1924 by J Clarke, Streptococcus mutans has been the focus of rigorous research efforts due to its involvement in caries initiation and progression. Its ability to ferment a range of dietary carbohydrates can rapidly drop the external environmental pH, thereby making dental plaque inhabitable to many competing species and can ultimately lead to tooth decay. Acid production by this oral pathogen would prove suicidal if not for its remarkable ability to withstand the acid onslaught by utilizing a wide variety of highly evolved acid-tolerance mechanisms. The elucidation of these mechanisms will be discussed, serving as the focus of this review.
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Affiliation(s)
- Robert Matsui
- Room 449A Faculty of Dentistry, University of Toronto, 124 Edward St., Toronto, ON, M5G 1G6, Canada, Tel.: +1 416 979 4917 ext. 4592, Fax: +1 416 978 4936
| | - Dennis Cvitkovitch
- Room 449A Faculty of Dentistry, University of Toronto, 124 Edward St., Toronto, ON, M5G 1G6, Canada, Tel.: +1 416 979 4917 ext. 4592, Fax: +1 416 978 4936
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Kwon YR, Son KJ, Pandit S, Kim JE, Chang KW, Jeon JG. Bioactivity-guided separation of anti-acidogenic substances againstStreptococcus mutansUA 159 fromPolygonum cuspidatum. Oral Dis 2010; 16:204-9. [DOI: 10.1111/j.1601-0825.2009.01636.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lemme A, Sztajer H, Wagner-Döbler I. Characterization of mleR, a positive regulator of malolactic fermentation and part of the acid tolerance response in Streptococcus mutans. BMC Microbiol 2010; 10:58. [PMID: 20178568 PMCID: PMC2834670 DOI: 10.1186/1471-2180-10-58] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 02/23/2010] [Indexed: 11/21/2022] Open
Abstract
Background One of the key virulence determinants of Streptococcus mutans, the primary etiological agent of human dental caries, is its strong acid tolerance. The acid tolerance response (ATR) of S. mutans comprises several mechanisms that are induced at low pH and allow the cells to quickly adapt to a lethal pH environment. Malolactic fermentation (MLF) converts L-malate to L-lactate and carbon dioxide and furthermore regenerates ATP, which is used to translocate protons across the membrane. Thus, MLF may contribute to the aciduricity of S. mutans but has not been associated with the ATR so far. Results Here we show that the malolactic fermentation (mle) genes are under the control of acid inducible promoters which are induced within the first 30 minutes upon acid shock in the absence of malate. Thus, MLF is part of the early acid tolerance response of S. mutans. However, acidic conditions, the presence of the regulator MleR and L-malate were required to achieve maximal expression of all genes, including mleR itself. Deletion of mleR resulted in a decreased capacity to carry out MLF and impaired survival at lethal pH in the presence of L-malate. Gel retardation assays indicated the presence of multiple binding sites for MleR. Differences in the retardation patterns occurred in the presence of L-malate, thus demonstrating its role as co-inducer for transcriptional regulation. Conclusion This study shows that the MLF gene cluster is part of the early acid tolerance response in S. mutans and is induced by both low pH and L-malate.
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Affiliation(s)
- André Lemme
- Helmholtz-Centre for Infection Research, Division of Cell Biology, Braunschweig, Germany.
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Assinder SJ. Effects of pH and Acid End-Products on Acid Production in Oral Streptococci. MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2009. [DOI: 10.3109/08910609509140088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- S. J. Assinder
- MRC Dental Group, Dental School, Lower Maudlin Street, Bristol, BS1 2LY, UK
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Potassium transport in corynebacterium glutamicum is facilitated by the putative channel protein CglK, which is essential for pH homeostasis and growth at acidic pH. J Bacteriol 2009; 191:2944-52. [PMID: 19270097 DOI: 10.1128/jb.00074-09] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We studied the requirement for potassium and for potassium transport activity for the biotechnologically important bacterium Corynebacterium glutamicum, which is used for large-scale production of amino acids. Different from many other bacteria, at alkaline or neutral pH, C. glutamicum is able to grow without the addition of potassium, resulting in very low cytoplasmic potassium concentrations. In contrast, at acidic pH, the ability for growth was found to depend on the presence of K+. For the first time, we provide experimental evidence that a potential potassium channel (CglK) acts as the major potassium uptake system in a bacterium and proved CglK's function directly in its natural membrane environment. A full-length CglK protein and a separate soluble protein harboring the RCK domain can be translated from the cglK gene, and both are essential for full CglK functionality. As a reason for potassium-dependent growth limitation at acidic pH, we identified the impaired capacity for internal pH homeostasis, which depends on the availability and internal accumulation of potassium. Potassium uptake via CglK was found to be relevant for major physiological processes, like the activity of the respiratory chain, and to be crucial for maintenance of the internal pH, as well as for the adjustment of the membrane potential in C. glutamicum.
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Law V, Seow WK, Townsend G. Factors influencing oral colonization of mutans streptococci in young children. Aust Dent J 2007; 52:93-100; quiz 159. [PMID: 17687953 DOI: 10.1111/j.1834-7819.2007.tb00471.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This paper aims to critically review current knowledge about the key factors involved in oral colonization of the cariogenic group of bacteria, mutans streptococci (MS) in young children. MS, consisting mainly of the species Streptococcus mutans and Streptococcus sobrinus, are commonly cultured from the mouths of infants, with prevalence of infection ranging from around 30 per cent in 3 month old predentate children to over 80 per cent in 24 month old children with primary teeth. MS is usually transmitted to children through their mothers, and the risk of transmission increases with high maternal salivary levels of MS and frequent inoculation. Factors that affect the colonization of MS may be divided into bacterial virulence, host-related and environmental factors. Complex interaction among these factors determine the success and timing of MS colonization in the child. As clinical studies have shown that caries risk is correlated with age at which initial MS colonization occurred, strategies for the prevention of dental caries should include timely control of colonization of the cariogenic bacteria in the mouths of young children.
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Affiliation(s)
- V Law
- School of Dentistry, The University of Queensland, Queensland, Brisbane
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Jakob K, Satorhelyi P, Lange C, Wendisch VF, Silakowski B, Scherer S, Neuhaus K. Gene expression analysis of Corynebacterium glutamicum subjected to long-term lactic acid adaptation. J Bacteriol 2007; 189:5582-90. [PMID: 17526706 PMCID: PMC1951826 DOI: 10.1128/jb.00082-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Corynebacteria form an important part of the red smear cheese microbial surface consortium. To gain a better understanding of molecular adaptation due to low pH induced by lactose fermentation, the global gene expression profile of Corynebacterium glutamicum adapted to pH 5.7 with lactic acid under continuous growth in a chemostat was characterized by DNA microarray analysis. Expression of a total of 116 genes was increased and that of 90 genes was decreased compared to pH 7.5 without lactic acid, representing 7% of the genes in the genome. The up-regulated genes encode mainly transcriptional regulators, proteins responsible for export, import, and metabolism, and several proteins of unknown function. As much as 45% of the up-regulated open reading frames code for hypothetical proteins. These results were validated using real-time reverse transcription-PCR. To characterize the functions of 38 up-regulated genes, 36 single-crossover disruption mutants were generated and analyzed for their lactic acid sensitivities. However, only a sigB knockout mutant showed a highly significant negative effect on growth at low pH, suggesting a function in organic-acid adaptation. A sigE mutant already displayed growth retardation at neutral pH but grew better at acidic pH than the sigB mutant. The lack of acid-sensitive phenotypes in 34 out of 36 disrupted genes suggests either a considerable redundancy in acid adaptation response or coincidental effects. Other up-regulated genes included genes for ion transporters and metabolic pathways, including carbohydrate and respiratory metabolism. The enhanced expression of the nrd (ribonucleotide reductase) operon and a DNA ATPase repair protein implies a cellular response to combat acid-induced DNA damage. Surprisingly, multiple iron uptake systems (totaling 15% of the genes induced >or=2-fold) were induced at low pH. This induction was shown to be coincidental and could be attributed to iron-sequestering effects in complex media at low pH.
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Affiliation(s)
- Kinga Jakob
- Lehrstuhl für Mikrobielle Okologie, Technische Universität München, D-85354 Freising, Germany
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Dashper SG, Liu SW, Reynolds EC. Antimicrobial Peptides and their Potential as Oral Therapeutic Agents. Int J Pept Res Ther 2007. [DOI: 10.1007/s10989-007-9094-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Penaud S, Fernandez A, Boudebbouze S, Ehrlich SD, Maguin E, van de Guchte M. Induction of heavy-metal-transporting CPX-type ATPases during acid adaptation in Lactobacillus bulgaricus. Appl Environ Microbiol 2006; 72:7445-54. [PMID: 16997986 PMCID: PMC1694267 DOI: 10.1128/aem.01109-06] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lactobacillus bulgaricus is a lactic acid bacteria (LAB) that, through the production of lactic acid, gradually acidifies its environment during growth. In the course of this process, L. bulgaricus acquires an improved tolerance to acidity. A survey of the recently established genome sequence shows that this bacterium possesses few of the pH control functions that have been described in other LAB and raises the question of what other mechanisms could be involved in its adaptation to the decreasing environmental pH. In some bacteria other than LAB, ion transport systems have been implicated in acid adaptation. We therefore studied the expression of this type of transport system during acid adaptation in L. bulgaricus by reverse transcription and real-time quantitative PCR and mapped transcription start sites. Intriguingly, the most significantly induced were three ATPases carrying the CPX signature of heavy-metal transporters. Protein homology and the presence of a conserved sequence motif in the promoter regions of the genes encoding these proteins strongly suggest that they are involved in copper homeostasis. Induction of this system is thought to assist in avoiding indirect damage that could result from medium acidification.
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Affiliation(s)
- S Penaud
- Génétique Microbienne, INRA-CRJ, 78352 Jouy en Josas cedex, France
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Lemos JAC, Brown TA, Abranches J, Burne RA. Characteristics of Streptococcus mutans strains lacking the MazEF and RelBE toxin-antitoxin modules. FEMS Microbiol Lett 2005; 253:251-7. [PMID: 16243456 DOI: 10.1016/j.femsle.2005.09.045] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 09/26/2005] [Accepted: 09/27/2005] [Indexed: 11/23/2022] Open
Abstract
Two pairs of genes were identified in Streptococcus mutans with similarity to relBE and mazEF toxin-antitoxin (TA) modules of Escherichia coli. Transcription of mazEF and relBE was repressed by amino acid starvation, and relBE expression was repressed by low pH. Mutants lacking MazF, RelE, or both toxins (MRT1) grew in broth media and formed biofilms as well as the parent. Biofilm populations of MRT1 were more resistant to acid killing than the parent or single mutants. MRT1 also exhibited a longer diauxie during growth on glucose and inulin and displayed decreased phosphoenolpyruvate:sugar phosphotransferase activity. This is the first report that demonstrates a physiological role for TA modules in Gram-positive bacteria.
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Affiliation(s)
- José A C Lemos
- Department of Oral Biology, University of Florida College of Dentistry, 1600 SW Archer Road, Gainesville, FL 32610-0424, USA
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