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Ye D, Liu Y, Li J, Zhou J, Cao J, Wu Y, Wang X, Fang Y, Ye X, Zou J, Ma Q. Competitive dynamics and balance between Streptococcus mutans and commensal streptococci in oral microecology. Crit Rev Microbiol 2024:1-12. [PMID: 39132685 DOI: 10.1080/1040841x.2024.2389386] [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: 03/22/2024] [Revised: 06/01/2024] [Accepted: 08/02/2024] [Indexed: 08/13/2024]
Abstract
Dental caries, as a biofilm-related disease, is closely linked to dysbiosis in microbial ecology within dental biofilms. Beyond its impact on oral health, bacteria within the oral cavity pose systemic health risks by potentially entering the bloodstream, thereby increasing susceptibility to bacterial endocarditis, among other related diseases. Streptococcus mutans, a principal cariogenic bacterium, possesses virulence factors crucial to the pathogenesis of dental caries. Its ability to adhere to tooth surfaces, produce glucans for biofilm formation, and metabolize sugars into lactic acid contributes to enamel demineralization and the initiation of carious lesions. Its aciduricity and ability to produce bacteriocins enable a competitive advantage, allowing it to thrive in acidic environments and dominate in changing oral microenvironments. In contrast, commensal streptococci, such as Streptococcus sanguinis, Streptococcus gordonii, and Streptococcus salivarius, act as primary colonizers and compete with S. mutans for adherence sites and nutrients during biofilm formation. This competition involves the production of alkali, peroxides, and antibacterial substances, thereby inhibiting S. mutans growth and maintaining microbial balance. This dynamic interaction influences the balance of oral microbiota, with disruptions leading to shifts in microbial composition that are marked by rapid increases in S. mutans abundance, contributing to the onset of dental caries. Thus, understanding the dynamic interactions between commensal and pathogenic bacteria in oral microecology is important for developing effective strategies to promote oral health and prevent dental caries. This review highlights the roles and competitive interactions of commensal bacteria and S. mutans in oral microecology, emphasizing the importance of maintaining oral microbial balance for health, and discusses the pathological implications of perturbations in this balance.
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Affiliation(s)
- Dingwei Ye
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yaqi Liu
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Li
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Zhou
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jingwei Cao
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yumeng Wu
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xinyue Wang
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuwen Fang
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xingchen Ye
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Zou
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qizhao Ma
- State Key Laboratory of Oral Diseases and National Center for Stomatology and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Liu S, Shao Y, Zhang Z, Xu W, Liu Y, Zhang K, Xu L, Zheng Q, Sun Y. SepM mutation in Streptococcus mutans clinical isolates and related function analysis. BMC Oral Health 2024; 24:730. [PMID: 38918777 PMCID: PMC11197336 DOI: 10.1186/s12903-024-04436-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 06/03/2024] [Indexed: 06/27/2024] Open
Abstract
BACKGROUND Streptococcus mutans (S. mutans) is an important pathogenic bacterium that causes dental caries, while Streptococcus gordonii (S. gordonii) is a non-cariogenic bacterium that inhibits the growth of S. mutans. The SepM protein can promote the inhibitory ability of S. mutans against S. gordonii by cleaving CSP-21 and activating the ComDE two-component system. This study was designed to explore sepM mutation in S. mutans clinical isolates and related function in the regulation of interactions with S. gordonii. METHODS The S. mutans clinical strains that can inhibit the growth of S. gordonii constitute the inhibitory group. 286 C-serotype S. mutans strains were categorized into S. gordonii inhibitory (n = 114) and non-inhibitory bacteria (n = 172). We detected sanger sequencing of sepM gene, the expression levels of related genes and proteins in clinical isolates, obtained prokaryotic expression and purification of mutated proteins, and analyzed the effect of the target mutations on the binding between SepM and CSP-21. RESULTS We found that C482T, G533A, and G661A missense mutations were presented at significantly higher frequency in the inhibitory group relative to the non-inhibitory group. There was no significant difference in the expression of the sepM gene between selected clinical isolates harboring the G533A mutation and the control group. The expression levels of SepM, phosphorylated ComD, and ComE in the mutation group were significantly higher than those in the control group. SepM_control and SepM_D221N (G661A at the gene level) were found to contain two residues close to the active center while SepM_G178D (G533A at the gene level) contained three residues close to the active center. At 25 °C and a pH of 5.5, SepM_D221N (G661A) exhibited higher affinity for CSP-21 (KD = 8.25 µM) than did the SepM control (KD = 33.1 µM), and at 25 °C and a pH of 7.5, SepM_G178D (G533A) exhibited higher affinity (KD = 3.02 µM) than the SepM control (KD = 15.9 µM). It means that it is pH dependent. CONCLUSIONS Our data suggest that increased cleavage of CSP-21 by the the mutant SepM may be a reason for the higher inhibitory effect of S. mutans on S. gordonii .
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Affiliation(s)
- Shanshan Liu
- Department of Stomatology, The First Affiliated Hospital of Bengbu Medical College, 287 Chuang Huai Road, Bengbu, 233004, China
- Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China
| | - Yidan Shao
- Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China
| | - Zhenzhen Zhang
- Department of Stomatology, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China
| | - Wen Xu
- Department of Biochemistry and Molecular Biology, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China
| | - Yudong Liu
- Department of Histology and Embryology, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China
| | - Kai Zhang
- Department of Stomatology, The First Affiliated Hospital of Bengbu Medical College, 287 Chuang Huai Road, Bengbu, 233004, China
| | - Li Xu
- Department of Stomatology, The First Affiliated Hospital of Bengbu Medical College, 287 Chuang Huai Road, Bengbu, 233004, China
| | - Qingwei Zheng
- Anhui Key Laboratory of Infection and Immunity, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China.
| | - Yu Sun
- Department of Biochemistry and Molecular Biology, Bengbu Medical College, 2600 Dong Hai Avenue, Bengbu, 233030, China.
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Zeng L, Walker AR, Burne RA, Taylor ZA. Glucose Phosphotransferase System Modulates Pyruvate Metabolism, Bacterial Fitness, and Microbial Ecology in Oral Streptococci. J Bacteriol 2023; 205:e0035222. [PMID: 36468868 PMCID: PMC9879115 DOI: 10.1128/jb.00352-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/08/2022] [Indexed: 12/12/2022] Open
Abstract
Spontaneous mutants with defects in the primary glucose phosphotransferase permease (manLMNO) of Streptococcus sanguinis SK36 showed enhanced fitness at low pH. Transcriptomics and metabolomics with a manL deletion mutant (SK36/manL) revealed redirection of pyruvate to production of acetate and formate, rather than lactate. These observations were consistent with measurements of decreased lactic acid accumulation and increased excretion of acetate, formate, pyruvate, and H2O2. Genes showing increased expression in SK36/manL included those encoding carbohydrate transporters, extracellular glycosidases, intracellular polysaccharide metabolism, and arginine deiminase and pathways for metabolism of acetoin, ethanolamine, ascorbate, and formate, along with genes required for membrane biosynthesis and adhesion. Streptococcus mutans UA159 persisted much better in biofilm cocultures with SK36/manL than with SK36, an effect that was further enhanced by culturing the biofilms anaerobically but dampened by adding arginine to the medium. We posited that the enhanced persistence of S. mutans with SK36/manL was in part due to excess excretion of pyruvate by the latter, as addition of pyruvate to S. mutans-S. sanguinis cocultures increased the proportions of UA159 in the biofilms. Reducing the buffer capacity or increasing the concentration of glucose benefited UA159 when cocultured with SK36, but not with SK36/manL, likely due to the altered metabolism and enhanced acid tolerance of the mutant. When manL was deleted in S. mutans or Streptococcus gordonii, the mutants presented altered fitness characteristics. Our study demonstrated that phosphotransferase system (PTS)-dependent modulation of central metabolism can profoundly affect streptococcal fitness and metabolic interactions, revealing another dimension in commensal-pathogen relationships influencing dental caries development. IMPORTANCE Dental caries is underpinned by a dysbiotic microbiome and increased acid production. As beneficial bacteria that can antagonize oral pathobionts, oral streptococci such as S. sanguinis and S. gordonii can ferment many carbohydrates, despite their relative sensitivity to low pH. We characterized the molecular basis for why mutants of glucose transporter ManLMNO of S. sanguinis showed enhanced production of hydrogen peroxide and ammonia and improved persistence under acidic conditions. A metabolic shift involving more than 300 genes required for carbohydrate transport, energy production, and envelope biogenesis was observed. Significantly, manL mutants engineered in three different oral streptococci displayed altered capacities for acid production and interspecies antagonism, highlighting the potential for targeting the glucose-PTS to modulate the pathogenicity of oral biofilms.
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Affiliation(s)
- Lin Zeng
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Alejandro R. Walker
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Robert A. Burne
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - Zachary A. Taylor
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
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Wang Z, Zeng Y, Cheng K, Cai Z, Zhou J. The quorum sensing system of Novosphingobium sp. ERN07 regulates aggregate formation that promotes cyanobacterial growth. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158354. [PMID: 36041622 DOI: 10.1016/j.scitotenv.2022.158354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/03/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Microbial aggregates play key roles in cyanobacterial blooms. Being a bacterial communication mechanism, quorum sensing (QS) synchronizes gene expression in a density-dependent manner and regulates bacterial physiological behavior. However, the regulatory role of QS in the formation of cyanobacteria-associated bacterial aggregates remains poorly understood. Here, we present insight into the role of QS in regulating bacterial aggregate formation in a representative bacterial strain, Novosphingobium sp. ERN07, which was isolated from Microcystis blooms in Lake Taihu. A biosensor assay showed that ERN07 exhibits significant AHL-producing capacity. Biochemical and microscopic analysis revealed that this strain possesses the ability to form aggregated communities. Gene knockout experiments indicated that the AHL-mediated QS system positively regulates bacterial aggregation. The aggregated communities possess the ability to enhance the production of extracellular polymeric substances (EPS), alter EPS composition ratios, and affect biofilm formation. The addition of aggregated substances also has a significant growth-promoting effect on M. aeruginosa. Transcriptomic analysis revealed that the aggregated substances positively regulate photosynthetic efficiency and energy metabolism of M. aeruginosa. These findings show that QS can mediate the aggregation phenotype and associated substrate spectrum composition, contributing to a better understanding of microalgal-bacterial interactions and mechanisms of Microcystis bloom maintenance in the natural environment.
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Affiliation(s)
- Zhaoyi Wang
- Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China
| | - Yanhua Zeng
- Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China; State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou 570228, Hainan Province, PR China
| | - Keke Cheng
- Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China
| | - Zhonghua Cai
- Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China
| | - Jin Zhou
- Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China.
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Zeng L, Walker AR, Calderon PDS, Xia X, Ren F, Esquivel-Upshaw JF. The Effect of Amino Sugars on the Composition and Metabolism of a Microcosm Biofilm and the Cariogenic Potential against Teeth and Dental Materials. J Funct Biomater 2022; 13:223. [PMID: 36412864 PMCID: PMC9680229 DOI: 10.3390/jfb13040223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/18/2022] [Accepted: 10/24/2022] [Indexed: 11/09/2022] Open
Abstract
Amino sugars N-acetylglucosamine (GlcNAc) and glucosamine (GlcN) are abundant sources of carbon and nitrogen in the oral cavity. The aim of this study was to investigate the effects of GlcNAc metabolism on the genomics and biochemistry of a saliva-derived microbial community, and on the surface integrity of human teeth and restorative surfaces. Pooled cell-containing saliva (CCS) was used to establish a microcosm biofilm in vitro in a biofilm medium (BM) containing 5 different carbohydrates. The microbial composition of each biofilm was analyzed by 16S rRNA amplicon sequencing, and the concentrations of eight organic acids were determined for selected sugars by targeted metabolomics. Meanwhile, extracted human teeth and polished titanium and ceramic disks were submerged in BM supplemented with 1% of glucose or GlcNAc, inoculated with CCS and Streptococcus mutans UA159, and incubated for 30 days. To mimic the effects of other microbial byproducts, the specimens were immersed in 10 mM hydrogen peroxide and 10 mM ammonium hydroxide for 30 days. The surface of each specimen was evaluated by profilometry for roughness (Ra) and imaged by scanning electron microscopy. The pH of the biofilm supernatant was significantly higher for the medium containing GlcNAc (p < 0.0001), and was higher in samples containing teeth than the two restorative disks for media containing the same sugar. For both teeth and titanium specimens, the samples treated with glucose-biofilm presented higher roughness values (Ra) than those with GlcNAc-biofilm and every other group. SEM images of the teeth and titanium disks largely supported the profilometry results, with glucose-biofilm samples demonstrating the largest deviation from the reference. For ceramic disks, slightly higher Ra values were obtained for the ammonia group. These findings provide the first direct evidence to support the ability of amino sugars to significantly reduce the cariogenic potential of oral biofilms by altering their biochemistry and bacterial composition. Additionally, amino sugar metabolism appears to be less detrimental to teeth and restorative surfaces than glucose metabolism.
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Affiliation(s)
- Lin Zeng
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | - Alejandro Riveros Walker
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | | | - Xinyi Xia
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Fan Ren
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Josephine F. Esquivel-Upshaw
- Department of Restorative Dental Sciences, Division of Prosthodontics, University of Florida, Gainesville, FL 32611, USA
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Liao Y, Zhang M, Lin X, Yan F. Diaryl Urea Derivative Molecule Inhibits Cariogenic Streptococcus mutans by Affecting Exopolysaccharide Synthesis, Stress Response, and Nitrogen Metabolism. Front Cell Infect Microbiol 2022; 12:904488. [PMID: 35619645 PMCID: PMC9127343 DOI: 10.3389/fcimb.2022.904488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022] Open
Abstract
Different small molecules have been developed to target cariogenic bacteria Streptococcus mutans. Based on target-based designing and in silico screening, a novel diaryl urea derivative, 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea (BPU), has previously been found effective in inhibiting the growth of S. mutans. However, the exact mechanism remains unclear. This current study aimed to explore the antimicrobial and antibiofilm effects of BPU on S. mutans and locate key enzymes and biological processes affected by the molecule via in silico molecular docking analysis and transcriptomic profile. Our in vitro results confirmed that BPU was capable of inhibiting planktonic growth as well as biofilm formation of S. mutans. The virtual binding analysis predicted that the molecule had strong binding potentials with vital enzymes (3AIC and 2ZID) involved in extracellular exopolysaccharide (EPS) synthesis. The predicted inhibitive binding was further confirmed by in vitro quantification of EPS, which found a decreased amount of EPS in the biofilms. The transcriptomic profile also found differential expression of genes involved in EPS synthesis. Moreover, the transcriptomic profile implied alterations in stress response and nitrogen metabolism in S. mutans treated with BPU. Examination of differentially expressed genes involved in these biological processes revealed that altered gene expression could contribute to impaired growth, biofilm formation, and competitiveness of S. mutans. In conclusion, the novel diaryl urea derivative BPU can inhibit the virulence of S. mutans by affecting different biological processes and serves as a potent anti-caries agent.
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Affiliation(s)
- Ying Liao
- Department of Pediatric Dentistry, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, China
| | - Mengyun Zhang
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, China
| | - Xingnan Lin
- School/Hospital of Stomatology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Fuhua Yan
- Department of Periodontology, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, China
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Spontaneous Mutants of Streptococcus sanguinis with Defects in the Glucose-Phosphotransferase System Show Enhanced Post-Exponential-Phase Fitness. J Bacteriol 2021; 203:e0037521. [PMID: 34460310 DOI: 10.1128/jb.00375-21] [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] [Indexed: 02/07/2023] Open
Abstract
Genetic truncations in a gene encoding a putative glucose-phosphotransferase system (PTS) protein (manL, EIIABMan) were identified in subpopulations of two separate laboratory stocks of Streptococcus sanguinis SK36; the mutants had reduced PTS activities on glucose and other monosaccharides. To understand the emergence of these mutants, we engineered deletion mutants of manL and showed that the ManL-deficient strain had improved bacterial viability in the stationary phase and was better able to inhibit the growth of the dental caries pathogen Streptococcus mutans. Transcriptional analysis and biochemical assays suggested that the manL mutant underwent reprograming of central carbon metabolism that directed pyruvate away from production of lactate, increasing production of hydrogen peroxide (H2O2) and excretion of pyruvate. Addition of pyruvate to the medium enhanced the survival of SK36 in overnight cultures. Meanwhile, elevated pyruvate levels were detected in the cultures of a small but significant percentage (∼10%) of clinical isolates of oral commensal bacteria. Furthermore, the manL mutant showed higher expression of the arginine deiminase system than the wild type, which enhanced the ability of the mutant to raise environmental pH when arginine was present. To our surprise, significant discrepancies in genome sequence were identified between strain SK36 obtained from ATCC and the sequence deposited in GenBank. As the conditions that are likely associated with the emergence of spontaneous manL mutations, i.e., excess carbohydrates and low pH, are those associated with caries development, we propose that glucose-PTS strongly influences commensal-pathogen interactions by altering the production of ammonia, pyruvate, and H2O2. IMPORTANCE A health-associated dental microbiome provides a potent defense against pathogens and diseases. Streptococcus sanguinis is an abundant member of a health-associated oral flora that antagonizes pathogens by producing hydrogen peroxide. There is a need for a better understanding of the mechanisms that allow bacteria to survive carbohydrate-rich and acidic environments associated with the development of dental caries. We report the isolation and characterization of spontaneous mutants of S. sanguinis with impairment in glucose transport. The resultant reprograming of the central metabolism in these mutants reduced the production of lactic acid and increased pyruvate accumulation; the latter enables these bacteria to better cope with hydrogen peroxide and low pH. The implications of these discoveries in the development of dental caries are discussed.
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Chen X, Daliri EBM, Tyagi A, Oh DH. Cariogenic Biofilm: Pathology-Related Phenotypes and Targeted Therapy. Microorganisms 2021; 9:microorganisms9061311. [PMID: 34208588 PMCID: PMC8234214 DOI: 10.3390/microorganisms9061311] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/06/2021] [Accepted: 06/14/2021] [Indexed: 01/02/2023] Open
Abstract
The initiation and development of cariogenic (that is, caries-related) biofilms are the result of the disruption of homeostasis in the oral microenvironment. There is a daily accumulation of dental biofilm on the surface of teeth and its matrix of extracellular polymers supports the host in its defense against invading microbes, thus helping to achieve oral microbial homeostasis. However, the homeostasis can be broken down under certain circumstances such as during long-term exposure to a low pH environment which results in the dominance of acidogenic and acid-tolerating species in the dental biofilm and, thus, triggers the shift of harmless biofilm to an acidic one. This work aims to explore microbial diversity and the quorum sensing of dental biofilm and their important contributions to oral health and disease. The complex and multispecies ecosystems of the cariogenic biofilm pose significant challenges for the modulation of the oral microenvironment. Promising treatment strategies are those that target cariogenic niches with high specificity without disrupting the balance of the surrounding oral microbiota. Here, we summarized the recent advances in modulating cariogenic biofilm and/or controlling its pathogenic traits.
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