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PubMed1974

Influence of incubation atmosphere on growth and amino acid requirements of Streptococcus mutans.

The growth response of Streptococcus mutans representing antigenic type a or d in a chemically defined medium was influenced by the oxygen concentration of the growth atmosphere. Under controlled aerobic (1.5% O(2)) conditions these cultures attained a greater density than when the atmosphere contained 0.006% O(2) or less. The growth of S. mutans strains representing antigenic types b or c in the defined medium was independent of the oxygen concentration of the growth environment. Under the conditions used in this study, none of the strains tested could utilize ammonium ion as a sole source of nitrogen for growth. The requirement for certain amino acids and inhibition by other amino acids varied with antigenic type and relative oxygen concentration of the growth environment. Under conditions where the atmospheric oxygen was reduced to 0.0006% O(2) or less, the amino acid requirements of the cultures became either more numerous or more stringent. S. mutans strains of type c generally required the least number of amino acids, whereas cultures of type d had more numerous requirements. Nearly every culture tested under the anaerobic atmosphere was inhibited by one of the branched-chain amino acids, leucine, valine, or isoleucine. Methionine and lysine were also found to be inhibitory, particularly toward the type c strains.

Amino Acids↗

PubMed1982

The acquisition of Streptococcus mutans by infant monkeys (Macaca fascicularis) and its relationship to the initiation of dental caries.

The acquisition and transmission of Streptococcus mutans by 16 consecutively born infant monkeys (Macaca fascicularis) was studied. The 16 infant monkeys were weaned in four groups and caged together to form a commune. Transmission from mother to infant occurred infrequently. Streptococcus mutans was isolated from nine of the mothers but only from the dental plaque of two infant monkeys at weaning at which time the predominant streptococci were S. sanguis and S. mitior. One further animal was colonized by S. mutants during the formation of the commune, but only after it was caged with an infant harbouring the same organism. For 46 d after the completion of the commune, the monkeys were fed a starch-based diet during which time S. mutans of serotypes c, e or h were isolated from the faeces of all 16 animals and from the dental plaque taken from the developmental groove of the first deciduous molar of 11 animals. Faecal transmission appeared to be an important factor in the spread of S. mutans between monkeys in the commune. The monkeys were then fed a caries-promoting high sucrose diet resulting in a rapid increase in the proportion of S. mutans in the plaque and in the faeces. Streptococcus mutans serotype e was more frequently isolated from both plaque and faeces and its predominance may in part be due to the production of a bacteriocin active in vitro against S. mutans serotype h and other species of oral streptococci isolated from monkey dental plaque. The proportion of S. mutans in the developmental groove 8 d after the introduction of the high sucrose diet was significantly related to both the caries status of the groove and the total caries score 6 months later. The results suggest that, in this model of human dental caries, S. mutans is the major bacterial factor in the initiation of tooth decay.

Aging↗

PubMed1975

Preparation and chemical composition of the cell walls of Streptococcus mutans.

Purified cell walls from Streptococcus mutans strain BHT were prepared without the use of proteolytic enzymes in order to retain all cell wall constituents for chemical analysis. Of four methods employed, the Ribi cell fractionator produced disrupted cell suspensions which could be most thoroughly purified on sucrose gradients. Results of chemical analyses on purified cell walls prepared in this 8.9% glycerol teichoic acid, 33.6% non-peptidoglycan polysaccharide, and 49.9% peptidoglycan.

Absorption↗

PubMed2002

[DNA vaccine encoding Streptococcus mutans surface protein protected gnotobiotic rats from caries].

OBJECTIVE: Protein of Streptococcus mutans is considered as one of the virulence factors due to its ability to mediate the initial attachment of Streptococcus mutans to tooth surface. In this study, an anticaries DNA vaccine pCIA-P was used to immunize rats. The expression of PAc in different tissues in vivo, specific immune response and protection effects against dental caries were observed. METHODS: Plasmid pCIA-P was injected into rats by two different routs: intramuscular injection (i.m.) and targeted salivary gland immunization (TSG). Immunohistochemistry technique was used to detect the expression of PAc. Gnotobiotic rats were vaccinated with pCIA-P by three different approaches: TSG, intramuscular injection and buccal mucosal injection (i.o.). The specific immune responses were evaluated by ELISA and their anticaries effects were evaluated by Keyes caries scores. RESULTS: PAc was expressed in the sarcoplasm and sarcolemma of muscle fibers and submandibular glands, especially strongly positive in duct regions. The levels of serum specific anti-PAc IgG and salivary specific anti-PAc IgA in TSG immunization and buccal mucosal immunization group were significantly higher than those of other groups. The Keyes caries scores of those two groups were significantly lower than those of other groups. CONCLUSION: The plasmid pCIA-P could provoke specific immune responses as a novel immunogen. Mucosal immunization with pCIA-P appears to be an effective genetic immunization method against dental caries.

Animals↗

PubMed1990

Cross-reactivity between the immunodominant determinant of the antigen I component of Streptococcus sobrinus SpaA protein and surface antigens from other members of the Streptococcus mutans group.

Most members of the Streptococcus mutans group of microorganisms specify a major cell surface-associated protein, SpaA, that is defined by its antigenic properties. The region of the spaA gene from Streptococcus sobrinus 6715 encoding the immunodominant determinant of the major antigenic component (antigen I) of the SpaA protein has recently been characterized. This study examined whether recognition of the immunodominant determinant is independent of the immunized animal host and whether antibodies elicited by the immunodominant determinant cross-react with cell surface proteins from S. mutans of various serotypes. Mouse and rabbit antisera to the undenatured SpaA protein reacted similarly both with the immunodominant determinant and with other antigenic structures of the protein in Western immunoblots with SpaA polypeptides that were specified by spaA gene fragments expressed in recombinant Escherichia coli. This suggests that the antibody responses of inbred and outbred animals were similar. Furthermore, antibodies raised against both the S. sobrinus SpaA immunodominant determinant expressed by recombinant E. coli and the purified protein from S. sobrinus displayed similar strain specificities and protein band profiles towards cells surface proteins from S. mutans of various serotypes in immunodot and Western blot analyses, respectively. This suggests that for S. sobrinus serotype g, the immune response against the SpaA protein is governed by the immunodominant determinant of antigen I. In addition, it indicates that the SpaA protein domain containing the immunodominant determinant overlaps the domain conferring cross-reactivity to cell surface proteins of S. mutans of various serotypes.

Animals↗

PubMed2001

Streptococcus mutans lipoteichoic acid-induced apoptosis in cultured dental pulp cells from human deciduous teeth.

Herein, we suggest that Streptococcus mutans lipoteichoic acid-induced death of dental pulp cells on human deciduous teeth is caused by apoptosis. We provide evidence for the causal role of apoptosis in this process by demonstrating an increase in the proportion of fragmented DNA in such dental pulp cells, which results in a ladder pattern of DNA fragmentation. Additionally, Streptococcus mutans lipoteichoic acid-induced apoptotic cell death is suppressed by caspase inhibitor. Collectively, these findings suggest that Streptococcus mutans lipoteichoic acids may cause apoptosis in human dental pulp cells, and serve as an important factor in pulpitis.

Apoptosis↗

PubMed2003

Isolation and biochemical characterization of mutacin VSM43 isolated from human oral Streptococcus mutans VSM43.

Bacteriocins produced by mutans streptococci are known as mutacins. Streptococcus mutans VSM43 isolated from human clinical oral cavity was screened for the production of mutacin. It can inhibit the growth of other mutans streptococci, many other gram-positives and some gram-negative bacteria. Average size of the inhibitory zone ranged between 12-20mm. The inhibitory activity could not be related to organic acids, bacteriophages and hydrogen peroxide. Mutacin VSM43 was protease sensitive, remained active within a pH range of 2-8, and lost activity after heating at 100 degrees C for 30 min. Mutacin VSM43 was dialyzable through dialysis membrane (pore size 12,000 Da). A titre of 1280 arbitrary/activity units per ml (AU/mL) was shown against Staphylococcus aureus AB211. Lacuna frequency percentage (LF%) against Streptococcus mutans VSMD and Staphylococcus aureus AB211 was 37% and 49% respectively. We are convinced mutacin VSM43 may be a parallel candidate for use against dental caries.

Journal Article↗

PubMed1999

Purification and properties of bacteriolytic enzymes from Bacillus licheniformis YS-1005 against Streptococcus mutans.

To find a novel lytic enzyme against cariogenic Streptococci, strains showing strong lytic activity have been screened from soil using Streptococcus mutans. A strain identified as Bacillus licheniformis secreted two kinds of lytic enzymes, which were purified by methanol precipitation, CM-cellulose chromatography, gel filtration, and hydroxyapatite chromatography. The molecular weights of these two enzymes, L27 and L45, were 27,000 and 45,000, respectively. Optimum pH and temperature of both enzymes for lytic activity were pH 8 and 37 degrees C. L27 and L45 digest the peptide linkage between L-Ala and D-Glu in peptidoglycan of Streptococcus mutans. The lytic activity was highly specific for Streptococcus mutans, suggesting their potential use as a dental care product.

Amino Acid Sequence↗

PubMed2006

Therapeutic effect of llama derived VHH fragments against Streptococcus mutans on the development of dental caries.

Streptococcus mutans is the main cause of dental caries. We evaluated the therapeutic effect of variable regions of a llama heavy chain antibody fragments directed against S. mutans named S36-VHH (S for Streptococcus) alone or fused with glucose oxidase (GOx) from Aspergillus niger. Western blot analysis and ELISA revealed binding of the S36-VHH to the streptococcal antigen I/II adhesin molecule of S. mutans serotype C. In a rat-desalivated caries model, daily administration of S36-VHH significantly reduced the development of smooth surface caries. No additional therapeutic effect of GOx was observed. Our results suggest that llama VHH antibodies may be a potential benefit as prophylaxis against dental caries.

Animals↗

PubMed1983

Influence of growth conditions on adherence of Streptococcus mutans ingbritt to saliva-coated hydroxyapatite.

Streptococcus mutans Ingbritt grown under standardized conditions adhered less effectively to saliva-coated hydroxyapatite beads than did Streptococcus sanguis G9B, and there was competition for binding. The results with Ingbritt were influenced by the generation time, the pH of growth, and the carbohydrate source as shown by studies on organisms grown in continuous culture.

Adsorption↗

PubMed2002

Multiple Streptococcus mutans Genes Are Involved in Biofilm Formation.

Streptococcus mutans has been strongly implicated as the principal etiological agent in dental caries. One of the important virulence properties of these organisms is their ability to form biofilms known as dental plaque on tooth surfaces. Since the roles of sucrose and glucosyltransferases in S. mutans biofilm formation have been well documented, we focused our attention on sucrose-independent factors. We have initially identified several mutants that appear to be defective in biofilm formation on abiotic surfaces by an insertional inactivation mutagenesis strategy applied to S. mutans. A total of 27 biofilm-defective mutants were isolated and analyzed in this study. From these mutants, three genes were identified. One of the mutants was defective in the Bacillus subtilis lytR homologue. Another of the biofilm-defective mutants isolated was a yulF homologue, which encodes a hypothetical protein of B. subtilis whose function in biofilm formation is unknown. The vast majority of the mutants were defective in the comB gene required for competence. We therefore have constructed and examined comACDE null mutants. These mutants were also found to be attenuated in biofilm formation. Biofilm formation by several other regulatory gene mutants were also characterized using an in vitro biofilm-forming assay. These results suggest that competence genes as well as the sgp and dgk genes may play important roles in S. mutans biofilm formation.

Biofilms↗

PubMed1992

pH regulation by Streptococcus mutans.

The intracellular pH (pHi) optimum for glycolysis in Streptococcus mutans Ingbritt was determined to be 7.0 by use of the ionophore gramicidin for manipulation of pHi. Glycolytic activity decreased to zero as the pHi was lowered from 7.0 to 5.0. In contrast, glycolysis had an extracellular pH (pHo) optimum of 6.0 with a much broader profile. The relative insensitivity of glycolysis to the lowering of pHo was attributed to the ability of S. mutans to maintain a transmembrane pH gradient (delta pH, inside more alkaline) at low pHo. At a pHo of 5.0, glycolyzing cells of S. mutans maintained a delta pH of 1.37 +/- 0.09 units. The maintenance of this delta pH was dependent on the concentration of potassium ions in the extracellular medium. Potassium was rapidly taken up by glycolyzing cells of S. mutans at a rate of 70 nmol/mg dry weight/min. This uptake was dependent on the presence of both ATP and a proton motive-force (delta p). The addition of N-N'-dicyclohexylcarbodiimide (DCCD) to glycolyzing cells of S. mutans caused a partial collapse of the delta pH. Growth of S. mutants at pHo 5.5 in continuous culture resulted in the maintenance of a delta pH larger than that produced by cells grown at pH 7.0. These results suggest the presence of a proton-translocating F1Fo-ATPase in S. mutans whose activity is regulated by the intracellular pH and transmembrane electrical potential (delta psi). The production of an artificial delta p of 124 mV across the cell membrane of S. mutans did not result in proton movement through the F1Fo-ATPase coupled to ATP synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acids↗

PubMed1996

Effect of sucrose consumption on level of Streptococcus mutans in saliva.

The aim of the present paper was to study whether sucrose consumption may affect the level of salivary Streptococcus mutans. The study was justified by the disagreement between results of "in vitro", animal and human experiments and results of epidemiological studies made on study-populations. According to experimental research, sucrose availability promotes Streptococcus mutans selection and development in the oral cavity. On the other hand, the results of epidemiological studies run counter to these experiments. In the present study, the main reasons for this disagreement were investigated and identified. From this, an epidemiological study was performed, taking into account these potentially confounding factors. The results show that sucrose consumption is actually able to promote Streptococcus mutans selection and development in the oral cavity, thus increasing the risk of dental caries.

Child↗

PubMed1983

Sequential mutagenesis of drug resistance in Streptococcus mutans during synchronous replication.

The frequency of nitrosoguanidine-induced mutation for streptomycin-, bacitracin- and rifampicin-resistance was measured in Streptococcus mutans during synchronous replication after release from chloramphenicol inhibition. A clear peak of mutagenesis for each marker was observed at certain times during synchronous replication. These times were different for individual markers; the times of peaks for streptomycin-, bacitracin- and rifampicin-resistance were 13, 22 and 12 min, respectively. At a definite time after the first peak, there was a second one. The distances between the first and second peaks during the synchronous replication were identical for all markers and approximately 50 min which represents the doubling time of the organisms. These results indicate that nitrosoguanidine causes sequential mutagenesis for these three markers in Streptococcus mutans when the growth is resumed after chromosome alignment, so that the methods may be useful in determining the sequence of gene replication for various markers in Streptococcus mutans.

Anti-Bacterial Agents↗

PubMed1976

Immunological relationships between glucosyltransferases from Streptococcus mutans serotypes.

Partially purified glycosyltransferase enzymes for Streptococcus mutans GS-5 (serotype c) have been utilized to prepare antibodies directed against the soluble glucan-synthesizing activity, GTF-B, and the insoluble-soluble glucan synthetic activity, GTF-A. Anti-GTF-A inhibited insoluble glucan formation catalyzed by the extracellular enzymes from strains GS-5 and FA-1 (serotype b) to a much greater extent than that of strains HS-6 (serotype a) or OMZ-176 (serotype d). This antibody fraction also inhibited both the cell-associated glucosyltransferase activities as well as the sucrose-mediated adherence of cells to glass surfaces by strains GS-5 and FA-1 but not that of strains HS-6 and OMZ-176. Anti-GTF-B inhibited soluble glucan formation catalyzed by the extracellular enzymes of strains GS-5 but not that of strain HS-6, FA-1, or OMZ-176. However, this antibody fraction did not strongly inhibit either the cell-associated glycosyltransferase activity or cellular adherence of any of the four strains. These results with body antibody fractions were also correlated with the ability of the antibodies to agglutinate the cells and form precipitin bands after immunodiffusion with the extracellular enzymes. Antibody prepared against the homogeneous soluble glucan-synthesizing enzyme demonstrated similar effects to the anti-GTF-B fraction. These results are discussed in terms of the antigenic relationships existing between the glucosyltransferases from different serotypes of S. mutans.

Antibodies, Bacterial↗

PubMed1999

[Separation and selection of salivary adhesion receptors of Streptococcus mutans to tooth surface].

OBJECTIVE: To select and purify salivary receptors of Streptococcus mutans from experimental salivary acquired pellicle. METHODS: Experimental salivary acquired pellicle (SAP) was performed by coating hydroxyapatite (HA) with whole saliva. Then SAP was washed from HA by 1 mol/L NaCl and 0.5 mol/L phosphate buffer sequentially. The proteins were further separated by chromatography of Sephadex G75 and DEAE-Sephadex A25. Receptors of Streptococcus mutans were selected by bacterial adhesion test and competitive inhibition adhesion test. Identification was performed by PAGE, SDS-PAGE, IP-PAGE and detection of amylase activity and inmunodifusion test. RESULTS: IgA degraded fragments, a protein of 13 kD and amylases were the receptors of S. mutans. The first two only promote the adhesion but the amylases can both promote and inhibit S. mutans adhesion. CONCLUSION: The adhesion of S. mutans to tooth surface is a result of interaction between adhesins of S. mutans and multiple salivary receptors.

Adhesins, Bacterial↗

PubMed1987

Environmental pH as a factor in the competition between strains of the oral streptococci Streptococcus mutans, S. sanguis, and "S. mitior" growing in continuous culture.

Strains of Streptococcus mutans (biotype 1), Streptococcus sanguis, and Streptococcus mitior have been grown in mixed continuous culture in a semidefined medium under glucose limitation at a growth rate of D = 0.1 h-1. The effect of varying the environmental pH on the proportions of the different populations within the community has been determined. Initially the populations were allowed to reach steady state at pH 7.0 when S. sanguis was dominant with S. mutans and "S. mitior" maintaining similar populations. The medium pH was then lowered in steps of 0.5 pH units from pH 7.0 to 4.5, and the community was grown at each step for at least 15 generations. Viable counts of each species were made at 24-h intervals. The population ratios established at pH 7.0 remained relatively stable when the environmental pH was set at pH 6.5. However, after the medium pH was lowered to 6.0 (days 18-27), the population of S. mutans began to increase and the S. mitior population began to decline. A further change was seen at pH 5.5 (days 27-34) when S. mutans became dominant, S. sanguis declined, and S. mitior was not detectable. At pH 4.5, both S. mutans and S. sanguis were reduced in numbers, but survived until the experimental run was terminated (44 days). Samples of culture fluid were taken throughout the experiment and analyzed for the presence of the acid products of glucose metabolism. The amounts of lactic acid produced by the community increased as the environmental pH was lowered.(ABSTRACT TRUNCATED AT 250 WORDS)

Culture Media↗

PubMed1980

Isolation and serotyping of Streptococcus mutans from teeth and feces of children.

Streptococcus mutans were detected in the feces from 10 of 29 caries-active patients, aged 4 to 9 years. The percentage of S. mutans to the total counts of facultatively anaerobic streptococci on mitis salivarius agar (Difco Laboratories) varied from 0 to 72.5%. S. mutans were then isolated from dental plaque of sound teeth and carious dentin of the 10 subjects known to harbor S. mutans in the feces. The frequency distribution of various serotypes of these dental and fecal isolates of S. mutans was compared by the immunodiffusion technique. Of the total 1,047 isolates (290 isolates from feces, 289 from dental plaque, and 468 from carious dentin), type c isolates were most prevalent (ca. 66%). Serotype d, e, f, and g isolates were also found but in far lower frequencies. Plural serotypes of S. mutans were occasionally found in dental and fecal samples of a single subject. For two subjects, relatively rare serotypes of S. mutans in the population examined, serotype e, f, or g, were predominantly found in their fecal and dental samples and those of their siblings and mother, suggesting an intrafamilial transmission of S. mutans.

Child↗