scholarly journals Virulence Factors of Streptococcus mutans Related to Dental Caries

2020 ◽  
Author(s):  
Bojanich María Alejandra ◽  
Orlietti Mariano Daniel
Keyword(s):  
Dental Caries ◽  
Streptococcus Mutans ◽  
Virulence Factors

scholarly journals Pleiotropic Regulation of Virulence Genes in Streptococcus mutans by the Conserved Small Protein SprV

2017 ◽  
Vol 199 (8) ◽  
Author(s):  
Manoharan Shankar ◽  
Mohammad S. Hossain ◽  
Indranil Biswas
Keyword(s):  
Dental Caries ◽  
Streptococcus Mutans ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Normal Growth ◽  
Hypothetical Protein ◽  
Bacteriocin Production ◽  
Transcript Levels ◽  
Content Type ◽  
Tooth Surfaces

ABSTRACT Streptococcus mutans, an oral pathogen associated with dental caries, colonizes tooth surfaces as polymicrobial biofilms known as dental plaque. S. mutans expresses several virulence factors that allow the organism to tolerate environmental fluctuations and compete with other microorganisms. We recently identified a small hypothetical protein (90 amino acids) essential for the normal growth of the bacterium. Inactivation of the gene, SMU.2137, encoding this protein caused a significant growth defect and loss of various virulence-associated functions. An S. mutans strain lacking this gene was more sensitive to acid, temperature, osmotic, oxidative, and DNA damage-inducing stresses. In addition, we observed an altered protein profile and defects in biofilm formation, bacteriocin production, and natural competence development, possibly due to the fitness defect associated with SMU.2137 deletion. Transcriptome sequencing revealed that nearly 20% of the S. mutans genes were differentially expressed upon SMU.2137 deletion, thereby suggesting a pleiotropic effect. Therefore, we have renamed this hitherto uncharacterized gene as sprV (streptococcal pleiotropic regulator of virulence). The transcript levels of several relevant genes in the sprV mutant corroborated the phenotypes observed upon sprV deletion. Owing to its highly conserved nature, inactivation of the sprV ortholog in Streptococcus gordonii also resulted in poor growth and defective UV tolerance and competence development as in the case of S. mutans. Our experiments suggest that SprV is functionally distinct from its homologs identified by structure and sequence homology. Nonetheless, our current work is aimed at understanding the importance of SprV in the S. mutans biology. IMPORTANCE Streptococcus mutans employs several virulence factors and stress resistance mechanisms to colonize tooth surfaces and cause dental caries. Bacterial pathogenesis is generally controlled by regulators of fitness that are critical for successful disease establishment. Sometimes these regulators, which are potential targets for antimicrobials, are lost in the genomic context due to the lack of annotated homologs. This work outlines the regulatory impact of a small, highly conserved hypothetical protein, SprV, encoded by S. mutans. We show that SprV affects the transcript levels of various virulence factors required for normal growth, biofilm formation, stress tolerance, genetic competence, and bacteriocin production.

Lemon myrtle extract inhibits lactate production by Streptococcus mutans

2021 ◽  
Vol 85 (10) ◽  
pp. 2185-2190
Author(s):  
Yukinori Yabuta ◽  
Yui Sato ◽  
Arisu Miki ◽  
Ryuta Nagata ◽  
Tomohiro Bito ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Dental Caries ◽  
Oral Cavity ◽  
Streptococcus Mutans ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Tooth Enamel ◽  
Lactate Production ◽  
Tooth Decay ◽  
Lactate Dehydrogenase Activity

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.

Virulence Factors of Mutans Streptococci: Role of Molecular Genetics

1993 ◽  
Vol 4 (2) ◽  
pp. 159-176 ◽  
Author(s):  
Howard K. Kuramitsu
Keyword(s):  
Dental Caries ◽  
Molecular Genetics ◽  
Streptococcus Mutans ◽  
Virulence Factors ◽  
Molecular Genetic ◽  
Mutans Streptococci ◽  
Mutant Analysis ◽  
Novel Approaches

Biochemical approaches were utilized initially to identify the virulence factors of the mutans streptococci (primarily Streptococcus mutans and S. sobrinu). Traditional mutant analysis of these organisms further suggested the important role of several of these factors in cariogenicity. However, because these mutations were not clearly defined, the utilization of cloned genes was necessary to verify their significance. The introduction of molecular genetic approaches for characterizing these factors has led not only to a clearer understanding of the role of these virulence factors in cariogenicity but has also suggested some novel approaches for reducing further the incidence of dental caries.

Cell Wall Ultrastructure in Three Strains of a Cariogenic Streptococcus

1971 ◽  
Vol 29 ◽  
pp. 338-339
Author(s):  
M. J. Kramer ◽  
Alan L. Coykendall
Keyword(s):  
Cell Wall ◽  
Dental Caries ◽  
Streptococcus Mutans ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Genetic Heterogeneity ◽  
Morphological Characteristics ◽  
Electron Microscopic ◽  
Dna Reassociation ◽  
Wall Ultrastructure

During the almost 50 years since Streptococcus mutans was first suggested as a factor in the etiology of dental caries, a multitude of studies have confirmed the cariogenic potential of this organism. Streptococci have been isolated from human and animal caries on numerous occasions and, with few exceptions, they are not typable by the Lancefield technique but are relatively homogeneous in their biochemical reactions. An analysis of the guanine-cytosine (G-C) composition of the DNA from strains K-1-R, NCTC 10449, and FA-1 by one of us (ALC) revealed significant differences and DNA-DNA reassociation experiments indicated that genetic heterogeneity existed among the three strains. The present electron microscopic study had as its objective the elucidation of any distinguishing morphological characteristics which might further characterize the respective strains.

Streptococcus Mutans Strains in Mother-Child Pairs of Children with Early Childhood Caries

2019 ◽  
Vol 43 (4) ◽  
pp. 252-256 ◽  
Author(s):  
Priya Subramaniam ◽  
Revathy Suresh
Keyword(s):  
Early Childhood ◽  
Dental Caries ◽  
Streptococcus Mutans ◽  
Early Childhood Caries ◽  
Mutans Streptococci ◽  
Similar Distribution ◽  
Healthy Children ◽  
Only Children ◽  
Polymerase Chain ◽  
Childhood Caries

Objective: Dental caries is both an infectious and transmissible disease. Maternal transfer of Mutans Streptococci occurs at an early age and is important in the initiation of dental caries in children. The aim of this study was to identify certain strains of Streptococcus mutans in mother-child pairs, of children with early childhood caries. Study design: Sixty mother-child pairs of healthy children aged 18–36 months were selected. Mothers with high levels of Streptococcus mutans in their saliva and only children with ECC were included. Dental plaque samples were collected from mother-child pairs. The plaque samples were stored, transferred to the laboratory and analyzed for Streptococcus mutans strains c, f, e and k, present in mother-child pairs using Real time Polymerase Chain Reaction (PCR) technique. Data obtained was subjected to statistical analysis for level of similarity in Streptococcus mutans strains present in mother-child pairs. Results: A similar distribution of Streptococcus mutans strains c, f and k was identified in 28 mother-child pairs. Streptococcus mutans strain e was seen in 18 pairs. Conclusion: Less than 50% of mother-child pairs showed similarity in distribution of Streptococcus mutans strains.

scholarly journals Oxidative Stressors Modify the Response of Streptococcus mutans to Its Competence Signal Peptides

2017 ◽  
Vol 83 (22) ◽  
Author(s):  
Matthew De Furio ◽  
Sang Joon Ahn ◽  
Robert A. Burne ◽  
Stephen J. Hagen
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Dental Caries ◽  
Signaling Pathway ◽  
Streptococcus Mutans ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Oral Biofilm ◽  
Genetic Competence ◽  
Content Type

ABSTRACTThe dental caries pathogenStreptococcus mutansis continually exposed to several types of stress in the oral biofilm environment. Oxidative stress generated by reactive oxygen species has a major impact on the establishment, persistence, and virulence ofS. mutans. Here, we combined fluorescent reporter-promoter fusions with single-cell imaging to study the effects of reactive oxygen species on activation of genetic competence inS. mutans. Exposure to paraquat, which generates superoxide anion, produced a qualitatively different effect on activation of expression of the gene for the master competence regulator, ComX, than did treatment with hydrogen peroxide (H2O2), which can yield hydroxyl radical. Paraquat suppressed peptide-mediated induction ofcomXin a progressive and cumulative fashion, whereas the response to H2O2displayed a strong threshold behavior. Low concentrations of H2O2had little effect on induction ofcomXor the bacteriocin genecipB, but expression of these genes declined sharply if extracellular H2O2exceeded a threshold concentration. These effects were not due to decreased reporter gene fluorescence. Two different threshold concentrations were observed in the response to H2O2, depending on the gene promoter that was analyzed and the pathway by which the competence regulon was stimulated. The results show that paraquat and H2O2affect theS. mutanscompetence signaling pathway differently, and that some portions of the competence signaling pathway are more sensitive to oxidative stress than others.IMPORTANCEStreptococcus mutansinhabits the oral biofilm, where it plays an important role in the development of dental caries. Environmental stresses such as oxidative stress influence the growth ofS. mutansand its important virulence-associated behaviors, such as genetic competence.S. mutanscompetence development is a complex behavior that involves two different signaling peptides and can exhibit cell-to-cell heterogeneity. Although oxidative stress is known to influenceS. mutanscompetence, it is not understood how oxidative stress interacts with the peptide signaling or affects heterogeneity. In this study, we used fluorescent reporters to probe the effect of reactive oxygen species on competence signaling at the single-cell level. Our data show that different reactive oxygen species have different effects onS. mutanscompetence, and that some portions of the signaling pathway are more acutely sensitive to oxidative stress than others.

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