SEARCH · PubMed Health

Results for “Streptococcus mutans”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47Linked to original sources

PubMed1979

Practical method to facilitate estimation of Streptococcus mutans levels in saliva.

A method was developed to facilitate the estimation of Streptococcus mutans levels in saliva. Saliva-contaminated wodden spatulas were pressed directly against an elevated agar plate containing a selective medium. The results were compared with the number of S. mutans per 1 ml of paraffin-stimulated saliva. It was shown that the spatula method gave a good estimation of the level of S. mutans infection. The incubation was also made in expired air instead of 95% N2-5% CO2. The outgrowth was in good agreement with that after conventional incubation. The method is useful in epidemiological studies or in selecting persons at a high caries risk, and when ordinary saliva sampling cannot be done, for example in small children. Compared with conventional saliva sampling, this method requires less time and material at sampling as well as at the laboratory.

Adult↗

PubMed1975

Cross-reactions of Streptococcus mutans due to cell wall teichoic acid.

Antisera to the whole cells of Streptococcus mutans cross-reacted with antigen extracts from four other gram-positive species, as well as with those of three other oral streptococci. Similarly, antisera to these bacteria cross-reacted with extracts from S. mutans and with those from each other. Using a purified phenol extract of the walls of S. mutans, which was identified by chemical, immunochemical, and enzymatic analyses as glycerol teichoic acid, the cross-reactions were shown to be specific for a determinant of the teichoic acid backbone. Results were confirmed in immunodiffusion tests where clear bands of identify were shown. These observations point out the need for caution in sereological research empolying extracts of gram-positive bacteria and may be of interest in investigations of periodontal disease.

Antibodies, Bacterial↗

PubMed1983

Adherence of Streptococcus mutans to smooth surfaces in the presence of artificial sweeteners.

The adherence of Streptococcus mutans to smooth glass surfaces was studied in the presence of the artificial sweeteners, saccharin, acesulfame K and aspartame. The cells were grown aerobically in 2% yeast extract, 1% sucrose medium with artificial sweetener added in concentrations from 0.02 to 20.00 mg/ml. The artificial sweeteners tested reduced overall growth (adherent plus suspended cells), but observed growth was in favour of the adherent cells. As compared to the control optimum adherence was obtained using 2 mg/ml sodium saccharin, 2 to 20 mg/ml acesulfame K and 4 mg/ml aspartame.

Adhesiveness↗

PubMed1976

Cellular fatty acid composition of Streptococcus mutans and related streptococci.

The cellular fatty acid composition of 18 strains of Streptococcus mutans and 17 isolates of related streptococci were examined by gas-liquid chromatography. The cultures could be divided into two distinct groups on the basis of their fatty acids. The first group, which included S mutans and S salivarius, contained palmitic (16:0), octadecenoic (18:1), stearic (18:0), eicosenoic (20:1), and eicosanoic (20:0) acids. The presence of the two 20-carbon fatty acids distinguished S mutans and S salivarius from all of the other species. Two of the S mutans cultures were further distinguished by the presence of 19-carbon and 21-carbon cyclopropane acids. The second group included S sanguis, S mitis, S uberis, and a culture of Lancefield group C streptococci. The percentages of the major acids (16:0, 18:1, and 18:0) found in these species were essentially identical. A culture of Lancefield group E streptococci contained large amounts of 16:1 and 18:1 and small amounts of two unidentified acids which were not present in any of the other cultures.

Chromatography, Gas↗

PubMed2003

Immunogenicity and protective immunity induced by synthetic peptides associated with putative immunodominant regions of Streptococcus mutans glucan-binding protein B.

Glucan-binding protein B (GbpB) from Streptococcus mutans has been shown to induce protective immunity to dental caries in experimental models. Having recently sequenced the gbpB gene, our objective in this study was to identify immunogenic regions within the GbpB sequence for use in subunit vaccines. Potential regions of immunogenicity were sought by use of a matrix-based algorithm (EpiMatrix) to estimate the binding characteristics of peptides derived from the GbpB sequence by using a database of known major histocompatibility complex class II binding alleles. Screening the entire sequence revealed several peptides with estimated high binding probabilities. Two N-terminal 20-mer peptides (SYI and QGQ) subtending two of these regions were synthesized. A preliminary experiment, in which these peptides were synthesized in the multiple antigenic peptide format and were used to subcutaneously immunize Sprague-Dawley rats twice at a 21-day interval, revealed that the SYI peptide induced a higher percentage of responses to the inciting peptide as well as to intact GbpB, as measured by enzyme-linked immunosorbent assay. The effect of immunization with the SYI peptide construct on the cariogenicity of S. mutans was then investigated by immunizing weanling Sprague-Dawley rats twice at a 9-day interval with SYI or with phosphate-buffered saline. All rats were then orally infected with S. mutans strain SJ. After a 78-day infection period, the SYI-immunized groups had significant reductions in dental caries on both smooth and occlusal surfaces compared with the sham-immunized group. Thus, these experiments indicated that at least one linear sequence, derived from the N-terminal third of GbpB, was sufficiently immunogenic to induce a protective immune response in this experimental rat model for dental caries.

Amino Acid Sequence↗

PubMed2001

Characterization of a copper-transport operon, copYAZ, from Streptococcus mutans.

A copper-transport (copYAZ) operon was cloned from the oral bacterium Streptococcus mutans JH1005. DNA sequencing showed that the operon contained three genes (copY, copA and copZ), which were flanked by a single promoter and a factor-independent terminator. copY encoded a small protein of 147 aa with a heavy-metal-binding motif (CXCX(4)CXC) at the C-terminus. CopY shared extensive homology with other bacterial negative transcriptional regulators. copA encoded a 742 aa protein that shared extensive homology with P-type ATPases. copZ encoded a 67 aa protein that also contained a heavy-metal-binding motif (CXXC) at the N-terminus. Northern blotting showed that a 3.2 kb transcript was produced by Cu2+-induced Strep. mutans cells, suggesting that the genes were synthesized as a polycistronic message. The transcriptional start site of the cop operon was mapped and shown to lie within the inverted repeats of the promoter-operator region. Strep. mutans wild-type cells were resistant to 800 microM Cu2+, whereas cells of a cop knock-out mutant were killed by 200 microM Cu2+. Complementation of the cop knock-out mutant with the cop operon restored Cu2+ resistance to wild-type level. The wild-type and the mutant did not show any differences in susceptibility to other heavy metals, suggesting that the operon was specific for copper. By using a chloramphenicol acetyltransferase reporter gene fusion, the cop operon was shown to be negatively regulated by CopY and could be derepressed by Cu2+.

Amino Acid Sequence↗

PubMed2003

[The study of peptide vaccine HDS from Streptococcus mutans glucosyltransferase].

OBJECTIVE: To investigate the antigenicity of the peptide vaccine HDS from Streptococcus mutans glucosyltransferase and its ability to induce protective immune responses in an experimental rat model of dental caries. METHODS: Artificial antigen HDS-KLH, peptide HDS, glycosyltransferase were injected to immunize rats. Measurement of the specific anti-HDS, GTF IgG or IgA concentration in saliva and serum were undertaken by ELISA among the experimental groups. Gnotobiotic rat model was developed when challenged S. mutans and a caries promoting diet. The jaws of the rats were selected and dyed. The Keyes caries score for each jaw were counted. RESULTS: The level of serum and salivary specific anti-HDS IgG and IgA in the group immunized by HDS-KLH was significantly higher than that in control group (P < 0.05). The Keyes caries score of GTF, HDS and HDS-KLH immunized group were significantly lower than that of control group, especially lower in smooth tooth surface. CONCLUSION: Artificial antigen HDS-KLH could induce immune response. As a peptide vaccine, HDS-KLH could reduce the caries incidence in experimental rat model.

Animals↗

PubMed1975

Mannitol transport in Streptococcus mutans.

A hexitol-inducible, phosphoenolpyruvate-dependent phosphotransferase system was demonstrated in Streptococcus mutans. Cell-free extracts obtained from mannitol-grown cells from a representative strain of each of the five S. mutans serotypes (AHT, BHT, C-67-1, 6715, and LM7) were capable of converting mannitol to mannitol-1-phosphate by a reaction which required phosphoenolpyruvate and Mg2+. Mannitol and sorbitol phosphotransferase activities were found in cell-free extracts prepared from cells grown on the respective substrate, but neither hexitol phosphotransferase activity was present in extracts obtained from cells grown on other substrates examined. A heat-stable, low-molecular-weight component was partially purified from glucose-grown cells and found to stimulate the mannitol phosphotransferase system. Divalent cations Mn2+ and Ca2+ partially replaced Mg2+, while Zn2+ was found to be highly inhibitory.

Alcohol Oxidoreductases↗

PubMed1978

The influence of certain growth conditions on the phosphatase activity of Streptococcus mutans grown in batch and continuous culture.

Acid phosphatase activity was detected in Streptococcus mutans strain NCTC 10832, and both acid and alkaline phosphatase in strains 2M2 and K1R. In batch culture, activity was maximal by mid exponential phase for 2M2 and at the end of this phase for NCTC 10832. Alkaline, but not acid, phosphatase activity of 2M2 and K1R increased when the inorganic phosphate in the medium was low; this was considered due, at least partly, to inducible or derepressible enzymes. In continuous culture, acid phosphatase activity of NCTC 10832 varied with the sugar substrate. The activity was increased by cell disruption and the degree of this increase for cells grown on different sugars parallelled the amounts of extracellular, insoluble polysaccharide produced on those sugars. Activity was highest for glucose-grown whole cells and for sucrose-grown disrupted cells.

Acid Phosphatase↗

PubMed1995

Streptococcus-mutans-induced nephritis in rabbits: rheumatoid factors and nephritogenicity.

The pathogenesis of streptococcus-induced nephritides (SIN) involves immune complex-mediated inflammation; however, specific mechanisms are still poorly understood. Using preparations of two strains of Streptococcus mutans (SM) in attempts to induce SIN in rabbits, one preparation was strongly and the other virtually not nephritogenic. The non-nephritogenic preparation provided a negative control for our studies. Streptococcal components were present in circulating immune complexes (CIC) as well as in tissue-bound immune complexes (TIC), especially early in the disease. CIC and TIC also contained rheumatoid factors (RF), which tended to predominate in late stages of the disease. The nephritogenic and the non-nephritogenic preparations of SM shared the same major tissue-binding components and induced similar titers of antimicrobial antibodies, but differed significantly in their ability to induce CIC and RF. It is proposed that kidney-binding microbial components, antimicrobial antibodies and high serum concentration of RF are necessary and sufficient determinants for the pathogenesis of SIN in this rabbit model.

Animals↗

PubMed1986

The intra-oral effect on enamel demineralization of extracellular matrix material synthesized from sucrose by Streptococcus mutans.

The role of extracellular matrix material (EMM) synthesized from sucrose (S) by Streptococcus mutans IB-1600 in altering the demineralizing potential of artificial plaque was evaluated with an intraoral enamel demineralization test (IEDT). The artificial plaque samples were prepared from cells cultivated in Todd-Hewitt broth (THB) supplemented with various S concentrations and by mixing THB-grown cells with increasing proportions of EMM (heat-killed THB + 2% S-cultivated cells). The samples were also evaluated for cell density (DNA content) and acidogenicity in vitro (pH-stat), as well as for in situ pH changes during a 45-minute intra-oral test following a 10% glucose rinse. An increase in the proportion of EMM relative to cell density was associated with an increase in enamel demineralization. This trend reversed when the ratio of cells to EMM was less than 1:19. Experiments involving strains of S. mitis, S. sanguis, and S. salivarius suggested a similar effect of EMM. The intra-oral pH data suggest that the presence of EMM may enhance demineralization by altering diffusion properties of plaque.

Acids↗

PubMed1983

Isolation, partial purification and preliminary characterization of a bacteriocin from Streptococcus mutans Rm-10.

An extracellular bactericidal substance was isolated from the supernatant of Streptococcus mutans Rm-10 culture fluid and partially purified with 60% ammonium sulfate precipitation, differential centrifugation, and gel filtration on Sephadex G-200. There was a good correlation of the sensitivity profiles of indicator strains whether assayed on solid medium or with purified material from cell-free culture fluid, indicating that the same inhibitory substance is produced on solid medium and in broth. Vapor from organic solvents such as chloroform, acetone, ethanol, and ether as well as heat treatment at 100 degrees C for 30 min had little effect on the bactericidal factor. It was sensitive to trypsin and pronase and resistant to deoxyribonuclease, ribonuclease, lysozyme, and phospholipase C. The inhibitor was not infective, and electron microscopic studies failed to reveal phage or phage-like particles in concentrated solutions of the bactericidal material. The results indicate that the extracellular bactericidal substance is indeed a bacteriocin. Activity in broth cultures reached a maximum only after exponential growth had ceased. It was active against other streptococcal strains as well as strains of Actinomyces naeslundii, A. viscosus, Bacillus subtilis and Staphylococcus aureus, but not against strains of Fusobacterium nucleatum and Escherichia coli.

Actinomyces↗

PubMed1981

Separation and characterization of a protein antigen from cells of Streptococcus mutans.

A protein antigen, I/II, was purified from cells and culture supernatants of Streptococcus mutans (serotype c) by solubilization in urea followed by ion exchange chromatography and gel filtration. Immunological activity was retained after further purification by preparative sodium dodecyl sulphate--polyacrylamide gel electrophoresis (SDS--PAGE). The sedimentation coefficient was estimated to be approximately 8.7S by sucrose gradient centrifugation. The use of staining procedures, as well as the linear migration of this protein through different concentrations of acrylamide during SDS--PAGE, indicated that the antigen is probably not a glycoprotein. A lower molecular weight protein containing the free antigen I determinant was shown to have extensive homology with intact antigen I/II which implied that the former was a degradation product of the intact 185 000 dalton antigen I/II. Antigen II, although previously defined by its resistance to proteases, could be further digested with trypsin after denaturation by SDS--PAGE. Antigen I/II could not be correlated with a group of glucosyltransferases isolated from whole cells and culture supernatants. The cell surface location of antigen I/II was established by the lactoperoxidase-catalysed iodination of intact cells followed by protein analysis using SDS--PAGE. Previously, the potential importance of antigen I/II has been established by its immunogenicity and capacity to induce a protective immune response against dental caries.

Antigens, Bacterial↗

PubMed1981

Effect of human saliva on the fluoride sensitivity of glucose uptake by Streptococcus mutans.

The fluoride (F) sensitivity of glucose uptake by whole cell suspensions of streptococcus mutans in the presence and absence of human whole salivary supernatant was studied. It was observed that dithiothreitol (DTT) and other thiols markedly reduced the F sensitivity of cells when saliva (50%, vol/vol) was present during glucose uptake. In the absence of saliva, cells were sensitive to 2 to 2.5 mM F regardless of the presence of thiols. Supplementation of cells in phosphate or tris(hydroxymethyl)aminomethane-hydrochloride buffers with physiological concentrations of calcium or phosphate had no effect on the F sensitivity of the organism. Experiments with permeabilized cells suggested that thiols themselves had no direct effect on the F sensitivity of enolase (a principal F target). Cells pretreated with DDT subsequently exhibited decreased F sensitivity when examined in the presence of saliva but not in the absence of saliva. Cells pretreated with whole salivary supernatant were found to be subsequently less sensitive to F in the absence of saliva during glucose uptake. Furthermore, in cases where cells were pretreated with saliva, subsequent additions of DDT were unnecessary to obtain maximal reduction in the F sensitivity of glucose uptake. It was concluded that the saliva-dependent reduction in F sensitivity of glucose uptake was not due to sequestration of available F by salivary constituents. The data suggest that a salivary component(s) interacts directly with the microorganism in some manner which results in reduced F sensitivity of the process under study. Possible mechanisms of saliva action are discussed.

Biological Transport↗

PubMed2000

Xylitol-induced elevated expression of the gbpC gene in a population of Streptococcus mutans cells.

Xylitol possesses a unique property distinct from the other caries-preventive sweeteners. This sugar alcohol cannot be metabolized to acids but is taken up by Streptococcus mutans and accumulated as a toxic sugar-phosphate in the cells, resulting in growth inhibition. Due to the accumulation, xylitol induces biological responses including the emergence of xylitol-insensitive populations. Therefore, we expected another response induced by xylitol and found a new phenomenon, that cells repeatedly cultured in the presence of xylitol evolved into those exhibiting an elevated dextran-dependent aggregation phenotype. This phenotype was found to result from expression of the gbpC gene, which was previously reported to be expressed only under certain stress conditions. Construction of a Strep. mutans isogenic mutant carrying the gbpC::lacZ fusion gene indicated that gbpC expression of cells repeatedly cultured in the presence of xylitol was elevated 20-fold. DNA transfer experiments indicated that this phenotypic change did not appear to be due to a mutation. These cells also exhibited decreased adhesion to glass surfaces when grown in the presence of sucrose. This may be one of the ways by which some populations of Strep. mutans are removed from dental plaques.

Adaptation, Physiological↗

PubMed1992

Effect of delmopinol on the cohesion of glucan-containing plaque formed by Streptococcus mutans in a flow cell system.

Glucan-containing plaque was formed by Streptococcus mutans adhering to saliva-coated glass slides in flow cells thermostated at 37 degrees C. The substrate was Brain Heart Infusion broth containing 1% sucrose and 10% sterile saliva. During the build-up of the plaque, which lasted for 29 h, the plaque was subjected to three two-minute exposures to either 0.1 mol/L sodium acetate buffer, pH 6.0, or the same buffer containing 6.4 mmol/L (0.2%) of the surface-active anti-plaque substance delmopinol hydro-chloride. The glass slides carrying the plaque were weighed, and plaques subjected to delmopinol treatment weighed only seven percent of the control plaques. The glass slides were then mounted in a beaker containing buffer, subjected to ultrasonication, and re-weighed. The delmopinol-treated plaques lost 59% of their wet weight upon sonication, while the controls lost only 19%. Control plaques having the same weight as delmopinol-treated plaques were not different from the control plaques grown for 29 h with regard to reduction of plaque weight after sonication. Transmission electron micrographs (TEM) showed a plaque dominated by globular or fibrillar matrix components in controls, while the delmopinol-treated plaque showed empty or unordered matrix areas between more densely packed cells. The TEM results were confirmed by scanning electron micrographs, which showed amorphous material associated with the bacterial cells in the control but not in the delmopinol-treated plaque. In conclusion, delmopinol reduced surface-associated glucan synthesis and lowered the cohesion of the plaque, indicating that glucan-containing plaque formed during repeated rinsings with delmopinol may be easier to remove by mechanical means than a non-treated plaque of this type.

Bacterial Adhesion↗

PubMed1998

Structure-activity study of the lantibiotic mutacin II from Streptococcus mutans T8 by a gene replacement strategy.

Mutacin II, elaborated by group II Streptococcus mutans, is a ribosomally synthesized and posttranslationally modified polypeptide antibiotic containing unusual thioether and didehydro amino acids. To ascertain the role of specific amino acid residues in mutacin II antimicrobial activity, we developed a streptococcal expression system that facilitates the replacement of the mutA gene with a single copy of a mutated variant gene. As a result, variants of mutacin II can be designed and expressed. The system was tested by constructing the following mutant peptides: delta N1, V7A, P9A, T10A, T10S, C15A, C26A, and C27A. All of these mutacin II variants except delta N1 and T10A, which were not secreted, were isolated, and their identities were verified by mass spectrometry. Variants P9A, C15A, C26A, and C27A failed to exert antimicrobial activity. Because the P9A and T10A variants comprise the "hinge" region of mutacin II, these observations suggest that in addition to the thioether and didehydro amino acids, the hinge region is essential for biological activity and biosynthesis or export of the peptide. Tandem mass spectrometry of the N-terminal part of the wild-type molecule and its C15A variant confirmed that the threonine at position 10 is dehydrated and present as a didehydrobutyrine residue. This analysis of the active T10S variant further suggested that a didehydro amino acid at this position is specific for antimicrobial activity and that the biosynthetic machinery does not discriminate between threonine and serine. In contrast, the lack of production of mutacin variants with alanine substituted for threonine at position 10, as well as the deletion of asparagine at the N terminus (delta N1), indicates that specific residues in the propeptide may be crucial for certain steps in the biosynthetic pathway of this lantibiotic.

Amino Acid Sequence↗

PubMed1979

Effect of growth rate and glucose concentration on the biochemical properties of Streptococcus mutans Ingbritt in continuous culture.

A comparison was made of the properties of Streptococcus mutans Ingbritt grown in continuous culture under conditions of excess glucose (nitrogen limitation) and limiting glucose at mean generation times of 1.7 to 14 h. Only low levels of glucoamylase-specific glycogen were formed in cells from either culture, and the total carbohydrate content of the cells under excess glucose was only at most 1.6-fold higher than in the glucose-limited culture. A negligible amount of cell-free polysaccharide was formed in either culture, although a significant level of glucosyltransferase activity was observed in both, with the highest activity at D = 0.2 and 0.4 h(-1) with a glucose limitation. Other differences were observed. (i) Lactate was the main end product of the glucose-excess culture, whereas acetate, formate, and ethanol were the main products of the glucose-limited culture except at a mean generation time of 1.5, when lactate represented 30% of the products. (ii) The yield (in grams per mole of glucose) of the latter culture was 2.6- to 4.0- fold higher than the yield of the glucose-excess culture. (iii) Washed cells from the glucose-limited culture were much more acidogenic (1.7- to 6.2-fold) than the glucose-excess cells when incubated with glucose, sucrose, and fructose. Endogenous glycolytic activity by the latter cells was significant, being 31 to 92% of the exogenous glucose rate at the four dilution rates. (iv) Cells from the glucose-excess culture were more insensitive to fluoride than cells from the glucose-limited culture. The NaF 50% inhibition dose values for the effect of fluoride on the metabolism of glucose, sucrose, and fructose were calculated for the four dilution rates at four pH values. This analysis indicated that rapidly metabolizing cells were more sensitive to fluoride than cells that metabolized the sugars more slowly.

Acetates↗