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PubMedDate not supplied

Compensatory levels of salivary IgM anti-Streptococcus mutans antibodies in IgA-deficient patients.

The protective role of salivary IgA in dental caries has not been completely demonstrated, so, in order to elucidate this point, we evaluated 15 totally and partially IgA-deficient children in terms of the following variables: dental caries indexes, bacterial plaques, number of Streptococcus mutans and Lactobacillus in the saliva, and titers of IgA, IgG and IgM anti-Streptococcus mutans antibodies in the saliva. Age-matched healthy children served as the control group. IgA-deficient children showed caries scores lower than those of the healthy children; in addition, no statistical difference was found between amount of dental plaque and numbers of the bacteria in saliva. The totally IgA-deficient children presented IgM in levels much higher than the healthy children (p < 0.05). These data could indicate a compensation for the IgA deficiency by IgM.

Antibodies, Bacterial↗

PubMed1976

[Inhibition effects of extracellular glucosyltransferase from Streptococcus mutans].

The extracellular, gel-electrophoretically pure glucosyl transferase (GT) of Streptococcus mutans st.227 was incubated with various inhibitors and the synthetic product quantitatively determined. The GT activity was increased with low urea concentration (0.3 - 1.2 M) and inhibited with higher urea molarity. Sodium dodecyl sulfate and quarternary ammonium compounds (detergents) have a clear inhibiting effect starting with 0.005%, while NaF, KSCN, ethylene diamine tetra-acetic acid and sugar alcohols do not have any influence.

Enzyme Inhibitors↗

PubMed2006

Differences between single- and dual-species biofilms of Streptococcus mutans and Veillonella parvula in growth, acidogenicity and susceptibility to chlorhexidine.

Streptococcus mutans, considered a primary pathogen in dental caries, thrives in dental plaque, which is a multispecies biofilm. Metabolic interactions between S. mutans and Veillonella parvula have been suggested. In this study we developed a biofilm model to quantify single-species (S. mutans or V. parvula) and dual-species (S. mutans and V. parvula) biofilm formation, and we identified the differences between the respective biofilms in terms of growth, acid formation, and response to chlorhexidine. Polystyrene 96-well microtiter plates were used for biofilm formation. These biofilms were exposed to various chlorhexidine concentrations (0.025-0.4 mg ml(-1)) and treatment conditions. Growth of the biofilms and the effects of chlorhexidine were evaluated by viable counts. Viability of the two species in all biofilm types was similar ( approximately 10(8) colony-forming units per well) after 72 h. Lactic acid accumulation of dual-species biofilms was significantly lower at 48 and 72 h than single-species biofilms of S. mutans. Dual-species biofilms were less susceptible to chlorhexidine than single-species biofilms when a neutralization step was included. These results indicate that bacteria in dual-species biofilms have different properties from bacteria in single-species biofilms.

Acetic Acid↗

PubMed1990

Complete nucleotide sequence of the sr gene from Streptococcus mutans OMZ 175.

The nucleotide sequence encoding the SR protein of Streptococcus mutans OMZ 175 (serotype f) has been determined. The sr gene consists of 4667 bp and codes for a 171177 Da protein. Comparison of the inferred amino acid sequence with the one of PAc antigen from S. mutans MT 8148 (serotype c) indicates a 88% conservation of amino acid residues which reflects the close relatedness of both proteins. Major differences in amino acid composition are located at the C-terminal part of the sequence where only 298 amino acids of the terminal 420 are conserved.

Amino Acid Sequence↗

PubMed1982

Identification of PK 1 bacteriophage DNA in Streptococcus mutans.

A lysogenic bacteriophage PK 1 and plasmid DNA's in Streptococcus mutans PK 1 have been characterized by electron microscopy PK 1 phage DNA molecules were observed in both linear and circular forms, which gave the molecular weights of (28.9 +/- 0.4) x 10(6) and (27.4 +/- 0.2) X 10(6) daltons, respectively. Plasmid DNA has a molecular weight of 4.0 X 10(6) daltons. No difference of density in CsCl density gradient between linear and circular forms of phage DNA and plasmid DNA was observed.

Bacteriophages↗

PubMed1986

Lysis of Streptococcus sanguis by an extracellular enzyme from the bacterium Streptococcus mutans from human dental plaque.

The ability of crude extracellular enzyme produced by the oral bacterium Streptococcus mutans AL7-1 to lyse living cells of Streptococcus sanguis ATCC 10556, 10557 and 10558 was examined. This enzyme showed lytic activity of living cells and cell walls of only Strep. sanguis ATCC 10558 strain and severed at random the long chains of this strain of living cells. Early log phase cells of this strain were more sensitive to this lytic enzyme than were late-log phase cells. In view of these results, the relationship between this lytic enzyme from Strep. mutans and a decrease in the number of serotype III strains of Strep. sanguis in dental plaque is discussed.

Antibiosis↗

PubMed1994

Genetic analysis of fructan-hyperproducing strains of Streptococcus mutans.

Fructan polymer, synthesized from sucrose by the extracellular fructosyltransferase of Streptococcus mutans, is thought to contribute to the progression of dental caries. It may serve as an extracellular storage polysaccharide facilitating survival and acid production. It may also have a role in adherence or accumulation of bacterial cells on the tooth surface. A number of clinical isolates of S. mutans which produce large, mucoid colonies on sucrose-containing agar as a result of increased production of fructan have been discovered. By using eight independent isolates, we sought to determine if such fructan-hyperproducing strains represented a genetically homogeneous group of organisms. Restriction fragment patterns of total cellular DNA were examined by using pulsed-field and conventional gel electrophoresis. Four genetic types which appeared to correlate with the serotype of the organism and the geographic site of isolation were evident. Southern blot analysis of several genetic loci for extracellular enzymes revealed some minor differences between the strains, but the basic genomic organizations of these loci were similar. To evaluate whether the excess fructan produced by these strains enhanced the virulence of these organisms in the oral cavity, it was of interest to create mutants deficient in fructosidase (FruA), the extracellular enzyme which degrades this polymer. The fruA gene was inactivated by allelic exchange in two fructan-hyperproducing strains as well as in S. mutans GS5, a strain which does not hyperproduce fructan. All of the fruA mutant strains were devoid of fructan hydrolase activity when levan was used as a substrate. However, the fructan-hyperproducing strains retained the ability to hydrolyze inulin, suggesting the presence of a second fructosidase with specificity for inulin in these strains.

Animals↗

PubMed2005

Streptococcus mutans murein hydrolase.

Allelic replacement of the C terminus of a Streptococcus mutans surface protein affects murein hydrolase activity. The targeted open reading frame encodes a 67-kDa protein (SmaA) with an N-terminal signal sequence and cleavage site, three 46-amino-acid (aa) direct repeats, and two 88-aa direct repeats. The identical autolytic profile was obtained using a sortase mutant (SrtA(-)).

Amino Acid Sequence↗

PubMed1986

Immunological study of lactate dehydrogenase from Streptococcus mutans and evidence of common antigenic domains with lactate dehydrogenases from lactic bacteria.

Rabbit polyclonal antibodies directed against purified Streptococcus mutans L-(+)-lactate dehydrogenase reacted with the purified enzyme, giving a marked deviation of its kinetic parameters. The enzyme affinity for pyruvate or NADH decreased in the presence of antibody, the affinity for fructose 1,6-diphosphate (FDP) appeared to be slightly affected, and the cooperativity of the ligand binding was lowered. A partial protective effect was observed when the enzyme was preincubated with FDP prior to the antibody adjunction. An enzyme-linked immunosorbent assay allowed detection of a 30% decrease in enzyme-antibody fixation when FDP was added. The protective effect observed with FDP could be correlated with a conformational change induced by the activator. A decrease of antibody binding in the presence of FDP was also obtained with S. sanguis, Actinomyces viscosus, and Lactobacillus casei lactate dehydrogenases, which reflects a similar mechanism of activation among lactic bacteria. NADH did not offer any protection against antibody inhibition or fixation, and the coenzyme affinity decrease could be attributed to an indirect mechanism. On the contrary, pyruvate and the immunoglobulins apparently could compete for specific binding sites. A decrease of antibody binding was also obtained with three heterologous lactic bacterial lactate dehydrogenases, indicating a conservation of antigenic determinants implicated in the substrate binding.

Actinomyces↗

PubMed1993

MsmE, a lipoprotein involved in sugar transport in Streptococcus mutans.

Metabolic labelling by [14C]palmitic acid showed that growth of Streptococcus mutans LT11 in raffinose, an inducer of the msm operon, resulted in increased production of a 45-kDa lipoprotein corresponding to MsmE, which is believed to be a sugar-binding protein. MsmE was also labelled when an msmE clone was expressed in Escherichia coli. The presence of a lipid anchor on MsmE provides a likely explanation of how the sugar-binding protein component of the msm binding protein-dependent multiple sugar transport system is retained at the cell surface.

Amino Acid Sequence↗

PubMed1984

Clinical isolates of Streptococcus mutans serotype c with altered colony morphology due to fructan synthesis.

Streptococcus mutans MT6801 , MT6861 , and MT6879 , which form large mucoid colonies on mitis salivarius agar, were isolated from a mother and her two daughters. These isolates were identified as serotype c by immunodiffusion with serotype-specific antisera. The large colonies formed on sucrose-containing agar were found to contain water-soluble fructan . The cell-free fructosyltransferase ( FTase ) activity of the strains which formed large colonies was five to eight times higher than that of serotype c S. mutans which produced small, rough colonies typical of this serotype. Furthermore, greater quantities of fructan were synthesized from sucrose by growing cells of MT6801 when compared with MT8148 , a typical serotype c S. mutans. Glucosyltransferase and FTase could be isolated by chromatofocusing from culture supernatants of MT6801 and MT8148 . The FTase activity of both strains was eluted at pH 4.5, and glucosyltransferase was released by elution with an NaCl linear gradient. The eluted FTase activity of MT6801 was significantly higher than that of MT8148 . Strains MT6861 and MT6879 were also found to possess a similar property in terms of FTase activity. These results suggest that formation of large mucoid colonies by these strains is a consequence of high FTase activity.

Adult↗

PubMed1982

Comparison fo agglutinin titers for Streptococcus mutans in tears, saliva, and serum.

The agglutinin titers for three Streptococcus mutans serotypes (AHT, BHT, and 10449, representing serotypes a, b, and c, respectively) were measured in the saliva, tears, and serum of 19 human subjects. Naturally occurring S. mutans agglutinins were routinely present in all fluids tested in the absence of overt local stimulation by antigen. The immunoglobulin A nature of this secretory agglutinin activity was suggested by blocking with alpha heavy-chain-specific antiserum and by the demonstration of S. mutans-reactive immunoglobulin A in the saliva and tears by indirect immunofluorescence. This finding is consistent with stimulation and antigen commitment of immunoglobulin A precursor lymphocytes at remote sites and subsequent homing to the lacrimal system. The relationship of anti-AHT agglutinins to anti-10449 agglutinins differed among the body fluids tested. The tears had more agglutinins for strain AHT than for strain 10449, whereas the reverse was true for saliva and serum. A possible explanation is local antigen-driven expansion of AHT-reactive committed lymphocytes in the lacrimal tissues.

Adult↗

PubMed1979

Antibiotic susceptibility of Streptococcus mutans: comparison of serotype profiles.

A total of 82 strains of Streptococcus mutans representing serotypes a through g were tested for susceptibility to erythromycin, penicillin, methicillin, lincomycin, tetracycline, vancomycin, gentamicin, streptomycin, neomycin, kanamycin, bacitracin, and polymyxin B. Strains included stock cultures and isolates from human and animal dental plaque. Minimal inhibitory concentrations were determined by a broth-microdilution procedure. The major differences in antibiotic susceptibility observed among the serotypes resulted with antibiotics which act on the cell surface. Bacitracin was most active against serotype a strains and polymyxin B against serotype b strains. Serotypes a, d, and g were less susceptible than the other serotypes to methicillin.

Anti-Bacterial Agents↗

PubMed1977

Specific method for the purification of Streptococcus mutans dextransucrase.

A convenient and rapid method for the purification of Streptococcus mutans dextransucrase is described. Affinity chromatography, on a column containing insoluble dextran purified from a culture of S. mutans 6715-49, gave an almost 300-fold purification, with 76% recovery of enzyme. Subsequent hydrophobic chromatography on butyl-agarose increased the overall enzyme purification to more than 1,000-fold, with a 65% recovery of activity. Two components of the dextransucrase activity were separated during hydrophobic chromatography. Both synthesized insoluble glucan as their major product and were capable of synthesizing soluble glucan in the presence of exogenous soluble dextran. However, the major enzyme component, which coeluted with a catalytically inert, dextran-binding protein, was greatly stimulated by exogenous soluble dextran, whereas the second enzyme component was not.

Cell-Free System↗

PubMed1985

Mouth-to-mouth transmission of the bacterium Streptococcus mutans between mother and child.

The production of bacteriocins by 314 Streptococcus mutans isolates from 20 mother-infant pairs was studied to test the likelihood of maternal transmission of this species. The patterns of inhibition were sufficiently different to allow differentiation of the 314 isolates into 41 bacteriocin types. The bacteriocin codes of isolates within one pair did not correspond to the codes of strains isolated from any other pair. The number of infant strains (per infant isolates) matching maternal strains within each mother-infant pair were 10/10, 10/10, 10/10, 12/12, 2/3, 10/10, 10/10, 10/10, 3/3, 5/10, 8/8, 3/3, 8/8, 3/3, 7/7, 4/4, 3/3, 8/8, 3/3 and 4/4 for pairs 1-20, respectively. Statistical analysis, utilizing a randomization test, generated a p value less than 0.0001, which is 12 standard errors above the level expected if the pairings were random.

Bacteriocins↗

PubMed1984

Effect of dextranase and protease enzymes on aggregation of Streptococcus mutans: colorimetric and electron microscopic studies.

Sucrose-induced aggregation of Streptococcus mutans was ascertained by measuring the decrease in optical density of a cell suspension after 20 h incubation. The optimum sucrose concentration for the aggregation assay was 5% w/v, at an incubation temperature of 37 degrees C. Dextranase and protease enzymes were added to the suspensions to determine their effects on aggregation. Dextranase treatment decreased aggregation. Electron microscopic studies revealed a reduction in the amount of a diffuse coat which surrounded cells in the absence of the enzyme but in the presence of sucrose, and a degradative effect on fibrous extracellular material. Protease treatment of suspensions produced an increase in optical density; cell aggregates were not apparent. Electron microscopic studies revealed extensive cell damage and lysis. The success of these enzymes in decreasing aggregation would indicate a role in both caries and plaque control in vivo.

Colorimetry↗

PubMed1991

Chromosomal deletions in melibiose-negative isolates of Streptococcus mutans.

Isolates from a collection of phenotypically melibiose-negative (Mel-) Streptococcus mutans from widely-scattered geographical locations were examined and found to lack the activities of the enzymes alpha-galactosidase and alpha-glucosidase, in addition to being unable to transport melibiose. Cloned fragments of S. mutans DNA from the region of the chromosome carrying the genes for alpha-galactosidase (aga), sucrose phosphorylase (gtfA), and dextran glucosidase (dexB), as well as the genes encoding components of the binding-protein-dependent uptake system for raffinose and melibiose, were used in hybridization studies for investigation of the genetic basis of the Mel-phenotype. A region of at least 12 kilobases, containing all the above genes, was found to be deleted from the chromosome of the Mel- strains. It appears that this region of the chromosome is not essential for survival of S. mutants in the oral cavity. The reason for the frequent occurrence of deletions, as opposed to other forms of mutational events, is unknown.

Biological Transport↗

PubMed1995

Effect of Porphyromonas gingivalis ATCC 33277 vesicle on adherence of Streptococcus mutans OMZ 70 to the experimental pellicle.

The vesicles of Porphyromonas gingivalis ATCC 33277 strongly aggregated Streptococcus cricetus, S. rattus, and S. mutans, but poorly aggregated S. sobrinus. The adherence of S. mutans OMZ 70 to hydroxyapatite (HA) coated with whole saliva was increased in parallel with the quantity of the vesicles. The significant increase of adherence of S. mutans OMZ 70 by the vesicles was also observed on the HA coated with parotid saliva, submandibular saliva, serum, and type I collagen. These findings suggest that the vesicles may act as a bridge between mutans streptococcus and the tooth surface.

Animals↗