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PubMed1976

Serological and genetic examination of some nontypical Streptococcus mutans strains.

Thirty-four strains of Streptococcus mutans whose antigenic or genetic positions were unclear or unknown with respect to the serological scheme of Bratthall (1970) and Perch et al. (1974), or the genetic (deoxyribonucleic acid base sequence homology) scheme of Coykendall were analyzed to clarify their relationship to previously well-characterized strains. Strain OMZ175 of the "new" serotype f was genetically homologous with strains of S. mutans subsp. mutans. Strains of the "new" serotype g were homologous with serotype d strains (S. mutans subsp. sobrinus). Strains isolated from wild rats constituted a new genetic group but carried the c antigen. Thus, strains within a "genospecies" (subspecies) of S. mutans may not always carry a unique or characteristic antigen. We suggest that the existence of multiple serotypes within subspecies represents antigenic variation and adaptations to hosts.

Animals↗

PubMed1984

Evidence for presence of a xylitol phosphotransferase system in Streptococcus mutans OMZ 176.

A cariogenic bacterial strain, Streptococcus mutans OMZ 176, was found to be able to take up xylitol by a phosphotransferase system (pts) in spite of lack of ability to catabolize this pentitol. A metabolite with an Rf value in TLC similar to xylitol 5-phosphate was extracted from resting cells which had been exposed to 14C xylitol. Phosphatase treatment of this metabolite yielded xylitol. It is suggested that the inhibition of growth of Strep. mutans observed in several laboratories can be explained in terms of accumulation of xylitol phosphate (presumably xylitol 5-phosphate) inside the cells. It is furthermore suggested that xylitol is transported and phosphorylated through the fructose pts.

Alkaline Phosphatase↗

PubMed1986

Demonstration of shared antigenic determinants between Streptococcus mutans BHT cell membrane, human heart tissue and myosin using monoclonal antibodies to S. mutans.

Monoclonal antibodies (MAb) raised to intact Streptococcus mutans P-4 cells (serotype e) were used to demonstrate the presence of shared antigenic determinant(s) between S. mutans BHT (serotype b) cell membranes and human heart tissue. MAb binding to both BHT membrane and human heart tissue was demonstrated by ELISA. Common antigens were identified by immunoblot analysis following separation of BHT membrane components and human heart antigens by SDS-PAGE. MAb 22C4 recognized three polypeptides from the BHT membrane preparation, having molecular masses of 42, 56 and 85 kDa. MAb 22C4 also recognized an 85 kDa component and a 200 kDa component from human heart tissue. MAb D159 was specific for a single 82 kDa polypeptide in BHT membrane, and also bound to two high molecular mass components in human heart (165 and 200 kDa). When both MAb D159 and 22C4 were first absorbed with S. mutans P-4 cells, subsequent reactivity to the aforementioned BHT membrane components was inhibited, indicating that these cross-reactive components are found in S. mutans P-4 as well as in S. mutans BHT micro-organisms. Competitive binding analysis showed that both MAb D159 and MAb 22C4 bound to myosin, indicating that S. mutans BHT membrane, human heart tissue and myosin share at least one immunodeterminant. This indicates that myosin could be the cross-reactive tissue component in human heart.

Antibodies, Bacterial↗

PubMed1996

Immunogenicity of peptides coupled with multiple T-cell epitopes of a surface protein antigen of Streptococcus mutans.

A surface protein antigen (PAc) of Streptococcus mutans, in particular the A-region of the molecule, has been noted as a possible target of effective dental caries vaccine. We have previously shown that two peptides of 19 amino acids (residues 361-379, NAKATYEAALKQYEADLAA, and residues 301-319, ANAANEADYQAKLTAYQTE), which correspond to parts of the A-region, contain both T- and B-cell epitopes for the induction of cross-reacting antibodies to the PAc. In this study, for development of an appropriate antigen as a peptide vaccine for use in prophylactic dentistry, we analysed in detail the localization of the T- and B-cell epitopes of PAc(361-379) peptide and the T-cell epitope of PAc(301-319) peptide in B10 congenic mice. In four murine major histocompatibility complex (MHC) haplotypes (H-2f,d,a and k), PAc(361-377) peptide showed T- and B-cell epitopes forming a cluster. It was found that the antibody which was induced by the immunization with the peptide was strongly cross-reactive with recombinant (r)PAc. Meanwhile, PAc(305-318) peptide, recognised by five strains of mice of different MHC haplotypes (H-2f,d,a,k and s), also bore multiple T-cell epitopes. PAc(361-377) peptide coupled to PAc(305-318) significantly elevated cross-reacting antibody levels compared to immunization with PAc(361-377) only in four H-2 haplotypes. Moreover, a peptide with PAc(305-318) coupled to the N-terminal region of PAc(361-377) produced significant cross-reacting antibody against rPAc, even in B10.S mice which had not responded to immunization with PAc(361-379) peptide. Therefore, it was suggested that coupling among the peptides forming a cluster might be effective in increasing immunogenicity. These results may provide us with a useful strategy for the design of peptide-based vaccines for S. mutans in the future.

Amino Acid Sequence↗

PubMed2006

Osmotic stress responses of Streptococcus mutans UA159.

The hyperosmotic stress response of Streptococcus mutans was investigated. Real-time reverse transcriptase-PCR and slot-blot analysis revealed that opuAA, opcA, Smu.2115, sodA and nox were induced after exposure to 0.4 M NaCl. Our data suggest that there is a cross-talk between osmotic and oxidative stress responses in S. mutans. Inactivation of Smu.2115, encoding a putative oxidoreductase, resulted in an acid-resistant and hydrogen peroxide-sensitive phenotype.

ATP-Binding Cassette Transporters↗

PubMed1991

Identification and initial characterization of glucose-repressible promoters of Streptococcus mutans.

Three catabolite-repressible promoters from Streptococcus mutans have been isolated. These promoters were identified by utilizing the vector pRQ200 which contains a promoterless amylase-encoding gene, a Gram- origin of replication, and an erythromycin-resistance determinant. A library of S. mutans DNA was constructed in pRQ200, amplified in Escherichia coli and integrated by Campbell-type insertion into the S. mutans chromosome following transformation. Colonies exhibiting amylase production on media lacking an extraneous carbohydrate source were screened for diminished amylase production on media containing glucose. The effect of glucose on these promoters has been characterized using a quantitative spectrophotometric assay of amylase activity.

Amylases↗

PubMed1994

Catabolite modification of acid tolerance of Streptococcus mutans GS-5.

The acid tolerance of Streptococcus mutans GS-5 in standard pH-drop assays was found to be affected by the sugar used in the assay and also by the sugar used for growth of the organism. For example, acid tolerance was lower when galactose was used as catabolite than when glucose was used, apparently because galactose/proton symport brought protons extruded by the F-ATPase back into the cell and thus reduced delta pH across the cell membrane. The acid tolerance of glycolysis was related directly to the capacities of the cells to produce acid glycolytically, or probably more correctly, to their capacities to produce adenosine triphosphate but not to acid tolerance of phosphotransferase systems for sugar uptake. Thus, glycolytic acid tolerance of S. mutans depends not only on environmental factors such as potassium or magnesium levels but also on the specific catabolites the organism is metabolizing or to which it has become metabolically adapted.

Adaptation, Physiological↗

PubMed1987

Protective secretory immunoglobulin A antibodies in humans following oral immunization with Streptococcus mutans.

Ingestion of a vaccine containing killed Streptococcus mutans, originally isolated from each volunteer, daily for 10 consecutive days induced increased levels of specific secretory immunoglobulin A (sIgA) antibodies to S. mutans cells and two cell surface proteins, glucosyltransferase and surface antigen I/II, in parotid saliva and tears of four healthy males and in parotid saliva, tears, colostrum, and milk of a pregnant woman. In addition, these antibodies inhibited glucosyltransferase activity. Both IgA1 and IgA2 antibodies were induced. The levels of IgA antibodies in all secretions remained significantly above preimmunization levels for more than 50 days after oral administration of antigen. A second series of immunizations for 7 consecutive days resulted in even higher levels of sIgA antibodies, which peaked earlier and persisted longer than those observed after the primary immunizations. No increase in levels of antibodies in serum were detected in any subject. Antibodies reactive with human heart and kidney antigens could not be detected in saliva, tears, colostrum, milk, or serum samples collected at any time during the immunization regimen. The numbers of viable S. mutans organisms in dental plaque and whole saliva decreased after each series of immunizations, which correlated with increased levels of IgA antibodies in saliva, suggesting that IgA antibodies in saliva were responsible for the reduced adherence of this bacterium. These results indicate that ingested S. mutans antigen induces secretion of specific IgA1 and IgA2 antibodies in saliva, tears, colostrum, and milk, providing further evidence for the existence of a common mucosal immune system.

Administration, Oral↗

PubMed2003

Effect of an orphan response regulator on Streptococcus mutans sucrose-dependent adherence and cariogenesis.

Streptococcus mutans is the principal acidogenic component of dental plaque that demineralizes tooth enamel, leading to dental decay. Cell-associated glucosyltransferases catalyze the sucrose-dependent synthesis of sticky glucan polymers that, together with glucan binding proteins, promote S. mutans adherence to teeth and cell aggregation. We generated an S. mutans Tn916 transposon mutant, GMS315, which is defective in sucrose-dependent adherence and significantly less cariogenic than the UA130 wild-type progenitor in germfree rats. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting, and N-terminal sequence analysis confirmed the absence of a 155-kDa glucosyltransferase S (Gtf-S) from GMS315 protein profiles. Mapping of the unique transposon insertion in GMS315 revealed disruption of a putative regulatory region located upstream of gcrR, a gene previously described by Sato et al. that shares significant amino acid identity with other bacterial response regulators (Y. Sato, Y. Yamamoto, and H. Kizaki, FEMS Microbiol. Lett. 186: 187-191, 2000). The gcrR regulator, which we call "tarC," does not align with any of the 13 proposed two-component signal transduction systems derived from in silico analysis of the S. mutans genome, but rather represents one of several orphan response regulators in the genome. The results of Northern hybridization and/or real-time reverse transcription-PCR experiments reveal increased expression of both Gtf-S and glucan binding protein C (GbpC) in a tarC knockout mutant (GMS900), thereby supporting the notion that TarC acts as a negative transcriptional regulator. In addition, we noted that GMS900 has altered biofilm architecture relative to the wild type and is hypocariogenic in germfree rats. Taken collectively, these findings support a role for signal transduction in S. mutans sucrose-dependent adherence and aggregation and implicate TarC as a potential target for controlling S. mutans-induced cariogenesis.

Amino Acid Sequence↗

PubMed1995

Assessment of salivary Lactobacillus and Streptococcus mutans counts following sodium fluoride mouthrinsing in Egyptian children.

The salivary Lactobacillus and Streptococcus mutans counts were assessed in 100 Egyptian children, initially before mouthrinsing with 0.05% sodium fluoride solution, 24 hours and 48 hours following rinsing. A statistically significant reduction in Lactobacillus and Streptococcus mutans counts of 49% and 44% respectively was obtained 24 hours following rinsing. This percentage decrease in both bacterial counts was reduced to 27% and 31% respectively, 48 hours following rinsing.

Child↗

PubMed1990

Oral immunization with recombinant Streptococcus lactis carrying the Streptococcus mutans surface protein antigen gene.

A recombinant Streptococcus lactis strain which carries the structural gene for a surface protein antigen (PAc) of 190,000 daltons from Streptococcus mutans serotype c was constructed for development of an oral vaccine against dental caries. The gene from S. mutans MT8148 joined to shuttle vector pSA3 was successfully transformed into S. lactis IL1403. A small amount of PAc was detected in the cell homogenate and cytoplasmic fraction of the recombinant S. lactis, but not in the culture supernatant of the recombinant, by Western immunoblotting and dot immunoblotting. The level of PAc-specific mRNA in the recombinant strain was lower than that in S. mutans MT8148. However, significant salivary immunoglobulin A and serum immunoglobulin G responses to PAc were induced in mice immunized orally with the recombinant S. lactis.

Animals↗

PubMed1978

Effect of sucrose in culture media on the location of glucosyltransferase of Streptococcus mutans and cell adherence to glass surfaces.

Streptococcus mutans strain B13 (serotype D) almost exclusively produced free glucosyltransferase (GTase) in the culture supernatant when grown in sucrose-free TTY broth medium, which was composed of Trypticase (Baltimore Biological Laboratory [BBL] Cockeysville, Md.), tryptose (Difco Laboratories, Detroit, Mich.), yeast extract (BBL), salts, and 1% glucose. Organisms grown in sucrose-free TTY broth retained very weak cell-associated GTase activity and did not adhere significantly to glass surfaces in the presence of exogenous sucrose. If sucrose was added to TTY broth, however, GTase was found on the cell surface where cell-bound, water-insoluble glucans were synthesized. Most commercially available products of Todd-Hewitt broth were found to contain trace amounts of sucrose, as did Trypticase soy broth (BBL), whereas brain heart infusion broth (Difco and BBL) was found to be essentially free of sucrose. Almost all detectable GTase activity was cell associated when S. mutans B13 was grown in Todd-Hewitt or trypticase soy broth. Heat-treated B13 cells grown in Todd-Hewitt broth and cell-free, water-insoluble glucans bound free GTase and produced marked adherence in the presence of sucrose. Experiments strongly suggest that the binding sites for free GTase are the surface glucans, and cell-associated and extracellular GTases are most likely alternate states of the same enzyme protein.

Culture Media↗

PubMed2007

Role of unsaturated fatty acid biosynthesis in virulence of Streptococcus mutans.

An insertionally inactivated fabM strain of Streptococcus mutans does not produce unsaturated membrane fatty acids and is acid sensitive (E. M. Fozo and R. G. Quivey, Jr., J. Bacteriol. 186:4152-4158, 2004). In this study, the strain was shown to be poorly transmissible from host to host. Animals directly infected with the fabM strain exhibited fewer and less severe carious lesions than those observed in the wild-type strain.

Animals↗

PubMed1978

Lactate dehydrogenase mutants of Streptococcus mutans: isolation and preliminary characterization.

Mutants of Streptococcus mutans were isolated which lack the enzyme activity L (+)-lactate dehydrogenase. Reversion studies indicate that the genetic defects are in the structural gene for the enzyme. The mutants produce less titratable acid from glucose, adhere better to hydroxyapatite, and accumulate more plaque when grown in the presence of sucrose than does the parent strain. These findings suggest a possible use for the mutants as effector strains in the replacement therapy of dental caries.

Adhesiveness↗

PubMed1981

Effect of calcium on reactions between a salivary agglutinin and a serotype c strain of Streptococcus mutans.

Using a serotype c strain of Streptococcus mutans we found that the agglutinating activity could be quantitatively absorbed, and desorbed from the micro-organisms by a phosphate buffer. The desorbed agglutinin was found to be inactive in the absence of calcium. Calcium alone did not induce aggregation. At 0.1 mM calcium most of the activity was regained. Other cations could not substitute for calcium. On a molecular basis the ratio between calcium and agglutinin or bacteria is high, in the order of 10(7) and 10(4) respectively.

Absorption↗

PubMed1976

Serum glucosyltransferase-inhibiting antibodies and dental caries in rhesus monkeys immunized against Streptococcus mutans.

Serum antibodies to glucosyltransferase (GTF) of Streptococcus mutans serotype c were assayed sequentially by means of an enzyme inhibition radio-assay in twenty-six Rhesus monkeys immunized with S. mutans. Pre-immune and control sera had a GTP-enhancing effect which was shown also by albumin and non-immune immunoglobulin fractions. GTF-inhibitory activity was found in IgG fractions from some immune sera and could be absorbed by S. mutans cells possessing cell-bound GTF. Inhibitory antibodies to GTF developed in the sera of four monkeys immunized with hydroxylapatite extract of culture supernatant (HACS), and in four out of fifteen monkeys immunized with S. mutans cells, but in none of the seven sham-immunized control animals. The monkeys immunized with HACS showed no reduction in caries. A correlation has been demonstrated between protection against caries and the early development of serum IgG antibodies to antigens present in HACS but there was no consistent association between protection against caries and GTF-inhibitory antibodies. The results also suggest the possibility that other antibodies, possibly present in the IgM or IgA fractions and having an enhancing effect on GTF, may increase the incidence of caries.

Animals↗

PubMed1978

Selective binding of blood group-reactive salivary mucins by Streptococcus mutans and other oral organisms.

Strains of Streptococcus mutans of four genetic groups and five serotypes, and strains of S. sanguis, S. mitis, S. salivarius, Actinomyces naeslundii, and A. viscosus, were found to bind blood group-reactive (BGR) mucin isolated from whole human saliva. The bacteria studied bound mucins with blood type A or B reactivity to a similar extent, suggesting that the carbohydrate moieties responsible for the A and B antigenic determinants were not involved. The organisms studied appeared to bind different fractions of BGR mucin molecules because preparations absorbed with cells of a given oral species no longer contained BGR molecules which bound to homologous organisms but still possessed BGR components which bound to varying degrees to other bacteria. Differences were even noted among S. mutans strains belonging to different genetic groups and serological types. Immunoglobulins could not be detected in the mucin preparations, and addition of anti-human immunoglobulin A (IgA), IgG, or IgM serum to reaction mixtures did not affect binding. Mucin pretreated with periodate or iodoacetate no longer bound to S. mutans H12 cells, suggesting that carbohydrate moieties and sulfhydryl groups played an essential role. Active cell metabolism was not required for BGR mucin binding; however, pretreatment of H12 cells with periodate or heat (100 degrees C for 15 min) reduced binding. Mucin labeled with [(14)C]phenyl isothiocyanate appeared to bind to S. mutans H12 cells comparably to untreated mucin; the binding also appeared to be specific because less than 15% of the labeled material became bound when incubated with an excess of streptococci. Binding of [(14)C]phenyl isothiocyanate-labeled mucin was not affected by neutral sugars tested or by preparations of c antigen, glycerol teichoic acid, dextran, or crude glucosyltransferase. However, binding was inhibited by several amines. BGR salivary mucins are present in the acquired pellicle covering teeth; the ability of bacteria to selectively bind such components suggest that they may serve as receptor molecules involved in the attachment of bacteria to teeth.

Actinomyces↗

PubMed1987

Effects of pH on expression of sodium fluoride resistance in Streptococcus mutans.

Stable fluoride-resistant mutants of Streptococcus mutans GS-5 were isolated on Todd-Hewitt agar by a step-wise selection procedure. Resistance is defined here as the ability to form colonies in 48 hr. First-step mutants demonstrated six different levels of resistance, ranging from 400 to 1000 micrograms/mL sodium fluoride. Second-step mutants demonstrated two levels of resistance, one at 1600 and the highest at 3000 micrograms/mL sodium fluoride. All mutants (originally isolated at pH 7.2) were tested for fluoride resistance at pH 5 and 6. At these lower pH values, all of the mutants demonstrated resistance to fluoride when compared with the parent strain, but at much-reduced levels.

Culture Media↗