PubMed Health⌕ Search

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 631 records · Page 35Linked to original sources
PubMedDate not supplied

[Quantitative evaluation of Streptococcus mutans and Candida species and salivary factors in the oral cavity of patient undergoing radiotherapy].

The aim of this study was to quantify the microorganisms Streptococcus mutans and Candida sp in the oral cavity of patients with oropharynx carcinoma, before, during and after radiotherapy, and to correlate the results with salivary factors such as pH, buffer capacity (CT) and flow rate (FS). Saliva samples were collected, diluted and inoculated in SB-20 agar and in Sabouraud agar, for Streptococcus mutans and Candida sp, respectively. Previously to dilution, the concentrated saliva was analyzed, and the salivary factors were determined. After the growth of colonies, the number of microorganisms was determined in CFU/ml. The analysis of the results allowed to conclude that the salivary factors are related to the presence of microorganisms, and that the number of CFU/ml increased as salivary flow rate decreased. The effects of radiation compromised salivary homeostasis and favored the increase of infection by yeasts and bacteria.

Analysis of Variance↗
PubMed1989

Production of mutacin-like substances by Streptococcus mutans.

Production of inhibitory substances by strains of the Streptococcus mutans group is well documented, but the nature of the substances implied is often unknown. Of nine laboratory strains known to produce inhibitory substances, the optimal conditions for producing inhibition zones on solid media were found to vary between strains but good production was generally obtained on all-purpose media with Tween 80 at 37 degrees C after 2-4 days of aerobic incubation. Streptococcus sanguis Ny101 was found to be more sensitive than Streptococcus rattus LG-1 to all inhibitory substances produced by the S. mutans strains tested. While all strains showed some inhibition, only six showed inhibition after neutralization; arginine incorporated in agar at 0.75% completely eliminated all inhibition zones. However 1% arginine in the overlays did not affect the production of inhibition zones by strains of S. mutans C67-1, Ny257, Ny266, and T8. These strains were shown to elaborate (in a reproducible fashion) inhibitory substances which were not organic acids. Inhibitory activity was never obtained in liquid preparations, except for strains Ny257 and T8 where it was found to be very unstable.

Aerobiosis↗
PubMed2002

Sequence of ultrastructural changes of enamel crystals and Streptococcus mutans biofilm in early enamel caries in vitro.

Undecalcified mature enamel sections were used to observe the sequence of ultrastructural changes of enamel crystals and Streptococcus mutans biofilm in the early stages of caries. Human enamel blocks were incubated from 1 to 7 days with S. mutans suspension, and the pH of biofilm was measured. They were processed for light microscopic and transmission electron microscopy observations, and the number of bacteria located in the area adjacent to enamel surface counted. It was observed that the pH of the biofilm dropped to 4, after 1-day of incubation and the S. mutans number increased until 4-day. Round shaped enamel crystals were observed in the 2-day specimens and from the 4-day, images of crystals showing defects and perforations were visualized, becoming more defective along the incubation days. The length of time that the enamel was exposed to biofilm was the main factor for enamel crystals demineralization. Current in vitro caries induction system could standardize time-related changes of the property of Streptococcus mutans biofilm and its relation to enamel crystals demineralization at the ultrastructural level, and thus provide a useful model for the evaluation of the effects of various anti-cariogenic agents.

Biofilms↗
PubMed1993

The level of mercury in human dental plaque and interaction in vitro between biofilms of Streptococcus mutans and dental amalgam.

Mercury levels (micrograms/mg dry weight) in dental plaque from amalgam and enamel surfaces in human subjects with amalgam restorations were (range, mean, SD) 0.5-1.31, 0.72, 0.34 and 0.01-0.54, 0.2, 0.19, respectively. The levels of mercury in plaque from amalgam surfaces were significantly higher than those from plaque on enamel (p < 0.001). No mercury was detected in plaque from subjects without amalgam restorations. The mean level of mercury in a 24-hour collection of plaque was 2 micrograms (median, 1.8 micrograms), an amount close to those calculated by other workers (1.2-1.7 micrograms) for the amount of mercury liberated in the mouth from amalgam restorations in 24 h. Freshly prepared amalgam liberated relatively large amounts of mercury into culture broth in the first 24 h of exposure; subsequently, the levels declined except in the presence of Streptococcus mutans. In vitro, biofilms of Streptococcus mutans facilitated the release of mercury from freshly prepared amalgam, in what appeared to be a cyclical fashion. Amalgam aged for two years did not release mercury, even when supporting the growth of an S. mutans biofilm. The resistance of aged amalgam was attributed to the presence of a passive tarnish layer. The mercury released by the biofilm had an effect on the composition of the biofilm. The biofilms on fresh amalgam had significantly lower levels of carbohydrate (p < 0.001-p < 0.01) and protein (p < 0.001-p < 0.02) than did biofilms on aged amalgam and on control stainless steel wires.

Adaptation, Physiological↗
PubMed1993

Branched-chain amino acid transport in Streptococcus mutans Ingbritt.

Leucine transport in glucose-energized cells of Streptococcus mutans exhibited Michaelis-Menten-type kinetics at low extracellular concentrations, with a K1 of 15.3 microM and a Vmax of 6.1 nmol/mg dry weight/min. At high extracellular leucine concentrations, the transmembrane diffusion of leucine was not saturable, indicating that passive diffusion becomes a significant mechanism of leucine transmembrane movement under these conditions. The proton motive force (PMF) was measured in glucose-energized cells of S. mutans and was found to have a maximum value of 126 mV at an extracellular pH (pH0) of 5.0; this decreased to 45 mV at pH0 8.0. The intracellular accumulation of leucine was significantly correlated with the magnitude of the PMF. The addition of excess isoleucine or valine caused a marked decrease in the leucine transport rate. Maximal rates of leucine transport occurred at pH0 6.0, and the rate of leucine transport was independent of the growth medium. The results suggest that there is a PMF-driven, branched-chain amino acid carrier in S. mutans with a proton: substrate stoichiometry of 1.

Amino Acids, Branched-Chain↗
PubMed1990

Use of transposon Tn916 to inactivate and isolate a mutacin-associated gene from Streptococcus mutans.

Among the attributes thought to contribute to the virulence of Streptococcus mutans is its ability to elaborate bacteriocinlike substances, which may provide a selective force enhancing its colonization potential. One such inhibitory substance, mutacin II, is produced by certain plasmid-containing strains of S. mutans. We introduced insertional mutations into a mutacin II-producing strain of S. mutans (UA96) by transformation with a plasmid carrying Tn916, resulting in transformants bearing single inserts of the transposon at different sites within the chromosome. The insertions identify five different EcoRI fragments required for production of mutacin II (Bac phenotype; bac-1 to bac-5 genotypes). The EcoRI fragments, containing bac-1::Tn916 was ligated into a cosmid vector, pJC74, and transduced into Escherichia coli DH1, where Tn916 is known to be unstable. The loss of Tn916 resulted in a 30-kb plasmid, pPC974, containing approximately 15 kb of S. mutans DNA. A Bac-associated DNA fragment was then subcloned into the streptococcus-E. coli shuttle vector pVA838 and transformed into S. mutants, where it was capable of complementing the bac mutation in the Bac- parent. These findings suggest that we have isolated at least one gene associated with mutacin production.

Bacteriocins↗
PubMed1986

Cloning and expression of a Streptococcus mutans glucosyltransferase gene in Bacillus subtilis.

The gtfA gene of Streptococcus mutans GS-5, which encodes a 55-kDa glucosyltransferase has been isolated from a genetic library in an Escherichia coli-Bacillus subtilis shuttle vector, pMK3. The construction containing the gene enables E. coli JM83 and a sucrase-deficient mutant of B. subtilis to grow on sucrose as the sole carbohydrate source. The gene is expressed under its own control in both organisms. The level of biochemical activity detectable in B. subtilis carrying the clone is approx. 50% of that found in E. coli harboring the same construction. In Bacillus, the gene is expressed through exponential and stationary phases of growth with a decrease in activity as the culture enters stationary phase, corresponding to increases in intracellular protease levels. The enzyme produced in E. coli or B. subtilis harboring the cloned gene is identical to the enzyme produced by S. mutans GS-5 as determined by migration in native polyacrylamide gels.

Bacillus subtilis↗
PubMed2004

Redirecting the humoral immune response against Streptococcus mutans antigen P1 with monoclonal antibodies.

The adhesin P1 of Streptococcus mutans has been studied as an anticaries vaccine antigen. An anti-P1 monoclonal antibody (MAb) bound to S. mutans prior to mucosal immunization of mice was shown previously to alter the amount, specificity, isotype, and biological activity of anti-P1 antibodies. The present study was undertaken to screen this and four additional anti-P1 MAbs for immunomodulatory activity when complexed with S. mutans and administered by a systemic route and to evaluate sera from immunized mice for the ability to inhibit adherence of S. mutans to immobilized human salivary agglutinin. All five MAbs tested influenced murine anti-P1 serum antibody responses in terms of subclass distribution and/or specificity. The effects varied depending on which MAb was used and its coating concentration. Two MAbs promoted a more effective, and two others a less effective, adherence inhibition response. An inverse relationship was observed between the ability of the MAbs themselves to inhibit adherence and the ability of antibodies elicited following immunization with immune complexes to inhibit adherence. Statistically significant correlations were demonstrated between the levels of anti-P1 serum immunoglobulin G2a (IgG2a) and IgG2b, but not of IgG1 or IgG3, and the ability of sera from immunized animals to inhibit bacterial adherence. These results indicate that multiple anti-P1 MAbs can mediate changes in the immune response and that certain alterations are potentially more biologically relevant than others. Immunomodulation by anti-P1 MAbs represents a useful strategy to improve the beneficial immune response against S. mutans.

Adhesins, Bacterial↗
PubMed1985

Transmission of the oral bacterium Streptococcus mutans to young Macaca fascicularis monkeys from human nursery attendants.

Streptococcus mutans was detected in the mouths of 2 out of 7 infant monkeys that had been delivered by caesarian section and nursery-reared without contact with their mothers or other monkeys. Their human nursery attendants all harboured Strep. mutans biotype c (c serotype) as found in the monkeys. Bacteriocin studies also indicated similarity between the animal and human isolates. These findings suggest that the infant monkeys acquired Strep. mutans from the nursery personnel. Evidence for the reverse transmission of enterococci, from monkeys to man was also obtained.

Animals↗
PubMed1987

Structure of the serotype f polysaccharide antigen of Streptococcus mutans.

The structure of the serotype f polysaccharide antigen of Streptococcus mutans was determined by methylation analysis, periodate oxidation, and partial methanolysis, and the configuration of the anomeric linkages by 13C-n.m.r. spectroscopy, indicating the trisaccharide repeating unit----3)-alpha-L-Rhap-(1----2)-[alpha-D-Glcp-(1----3)]-alpha-L-+ ++Rhap- (1----. The structure of the backbone of the polysaccharide was confirmed by demonstrating immunological identity between the product of Smith degradation of the S. mutans serotype f antigen and the group A-variant streptococcal polysaccharide.

Carbohydrate Conformation↗
PubMed1989

Serum IgG level against Streptococcus mutans in subjects with caries experience.

Serum IgG level against Streptococcus mutans serotype c was studied in 33 subjects, in relation to dental caries, oral hygiene and age. The activity of the serum IgG against the sonicated antigens of the bacterium was evaluated by micro-ELISA. The serum IgG titer to S. mutans was significantly higher in the subjects with no detectable carious lesions than in the subjects with active caries (p less than 0.05). However, there was no clear difference between the serum IgG antibody to S. mutans and the DMF index. The serum IgG antibodies to S. mutans were associated with the level of oral hygiene but not with age.

Adult↗
PubMed1998

Binding of salivary glycoprotein-secretory immunoglobulin A complex to the surface protein antigen of Streptococcus mutans.

The interaction between a surface protein antigen (PAc) of Streptococcus mutans and human salivary agglutinin was analyzed with a surface plasmon resonance biosensor. The major component sugars of the salivary agglutinin were galactose, fucose, mannose, N-acetylglucosamine, N-acetylgalactosamine, and N-acetylneuraminic acid. Binding of salivary agglutinin to PAc was calcium dependent and heat labile and required a pH greater than 5. Binding was significantly inhibited by N-acetylneuraminic acid and alpha2,6-linked sialic acid-specific lectin derived from Sambucus sieboldiana in a dose-dependent manner. Pretreatment of the salivary agglutinin with sialidase reduced the binding activity of the agglutinin to the PAc molecule. The agglutinin was dissociated into high-molecular-mass glycoprotein and secretory immunoglobulin A (sIgA) components by electrophoretic fractionation in the presence of 1% sodium dodecyl sulfate and 1% 2-mercaptoethanol. Neither of the components separated by electrophoretic fractionation, high-molecular-mass glycoprotein or sIgA, bound to the PAc molecule. Furthermore, the high-molecular-mass glycoprotein strongly inhibited the binding of the native salivary complex to PAc. These results suggest that the complex formed by the high-molecular-mass salivary glycoprotein and sIgA is essential for the binding reaction and that the sialic acid residues of the complex play an important role in the interaction between the agglutinin and PAc of S. mutans.

Acetylgalactosamine↗
PubMed1991

Adaptation of Streptococcus mutans and Enterococcus hirae to acid stress in continuous culture.

Streptococcus mutans GS-5 and IB1600 adapted to growth in acidic environments in continuous culture at slow (generation time = 8.3 h) or fast (generation time = 2.4 h) rates of growth in complex medium with a restricted glucose supply. The extent of adaptation was indicated by changes in minimum pH values attained by harvested cells suspended in dense suspensions with excess glucose and by increased levels of ATPase activity assayed in permeabilized cells. Also, adapted cells better withstood potentially lethal acidification. Cells harvested from cultures growing at pH values close to 5 reduced suspension pH to lower values than cells from cultures maintained at pH 7. Cells from pH 6 cultures were intermediate. The IB1600 strain had a higher level of constitutive acid resistance than the GS-5 strain and also was better able to adapt to growth in acidified media. Both had less adaptive capacity than Enterococcus hirae ATCC 9790. Adaptation occurred rapidly, mainly within a single generation in continuous culture, while deadaptation occurred more slowly over multiple generations. The capacity of S. mutans to adapt to acid conditions is likely to be important in the ecology of dental plaque and also for the cariogenicity of the organism.

Adaptation, Physiological↗
PubMed1982

Expression of Streptococcus mutans aspartate-semialdehyde dehydrogenase gene cloned into plasmid pBR322.

Streptococcus mutans chromosomal DNA cloned into the vector plasmid pBR322 in Escherichia coli is able to complement the metabolic defect of an aspartate-semialdehyde dehydrogenase (EC 1.2.1.11) gene (asd) deletion in the host strain. We constructed two Asd+ recombinant plasmids, pYA570 and pYA571, containing 4.7 and 4.5 kilobases, respectively, of S. mutans chromosomal DNA inserted into the HindIII restriction endonuclease site of pBR322 in the same orientation. The S. mutans UAB62 Asd+ DNA did not hybridize with E. coli DNA which contained an intact asd gene, but did not hybridize with S. mutans UAB62 chromosomal DNA. Derivative Asd+ plasmids were then constructed from pYA570. One, pYA574, had a 4.5 kilobase S. mutans insert DNA in the opposite direction from pYA570. In another pYA575, the S. mutans insert DNA was reduced in size to 1.3 kilobases. It was seen that the orientation of the S. mutans DNA fragment inserted into the promotor region of the pBR322 tetracycline resistance (Tcr) gene affected expression of Tcr. Orientation of the S. mutans insert also affected the stability of the plasmid in certain E. coli strains. Restriction maps for pYA570, pYA571, pYA574 and pYA575 using the endonucleases EcoRI, BamHI, HindIII, PstI and SalI were determined, Asd+ plasmid-directed protein synthesis was studied in E. coli minicells. The plasmids pYA570, pYA574 and pYA575 each produced large amounts of a protein with a monomeric molecular weight of about 45000, that was distinct from both pBR322 and E.coli specified proteins: this protein is the S. mutans asd gene product. Smaller derivatives of recombinant plasmid pYA575 that were Asd- allowed the location of the S. mutans asd gene promotor and the direction of transcription to be determined.

Aspartate-Semialdehyde Dehydrogenase↗
PubMed1985

Antibody specificity and antigen characterization of rat monoclonal antibodies against Streptococcus mutans cell wall-associated protein antigens.

Monoclonal antibodies to Streptococcus mutans OMZ175 (serotype f) cell wall-associated antigens (wall-extracted antigens [WEA]) were derived from the fusion of Lou C plasmocytoma rat cells (IR 983 F) and spleen cells from Wistar R inbred rats immunized with WEA. Four cell lines producing monoclonal antibodies directed against a component of S. mutans WEA have been established. All four monoclonal antibodies reacted only with two antigens of WEA from S. mutans OMZ175 by Western blotting and immunoprecipitation techniques, enzyme-linked immunosorbent assay (ELISA), and competitive ELISA. Western blot analysis of WEA showed that the four monoclonal antibodies recognized two related cell wall-associated proteins with apparent molecular weights of 125,000 and 76,000. Immunoprecipitation of whole cells with the monoclonal antibodies confirmed the surface localization of the two antigens. The ELISA and competitive ELISA were used to analyze the distribution of the epitopes on seven S. mutans serotypes. All S. mutans serotypes were found to express the recognized epitopes; however, different reactivity patterns could be distinguished among the various strains tested, and the four monoclonal antibodies reacted only weakly with S. mutans serotypes d and g.

Animals↗
PubMed1995

Glucose transport by a mutant of Streptococcus mutans unable to accumulate sugars via the phosphoenolpyruvate phosphotransferase system.

Streptococcus mutans transports glucose via the phosphoenolpyruvate (PEP)-dependent sugar phosphotransferase system (PTS). Earlier studies indicated that an alternate glucose transport system functions in this organism under conditions of high growth rates, low pH, or excess glucose. To identify this system, S. mutans BM71 was transformed with integration vector pDC-5 to generate a mutant, DC10, defective in the general PTS protein enzyme I (EI). This mutant expressed a defective EI that had been truncated by approximately 150 amino acids at the carboxyl terminus as revealed by Western blot (immunoblot) analysis with anti-EI antibody and Southern hybridizations with a fragment of the wild-type EI gene as a probe. Phosphotransfer assays utilizing 32P-PEP indicated that DC10 was incapable of phosphorylating HPr and EIIAMan, indicating a nonfunctional PTS. This was confirmed by the fact that DC10 was able to ferment glucose but not a variety of other PTS substrates and phosphorylated glucose with ATP and not PEP. Kinetic assays indicated that the non-PTS system exhibited an apparent Ks of 125 microM for glucose and a Vmax of 0.87 nmol mg (dry weight) of cells-1 min-1. Sugar competition experiments with DC10 indicated that the non-PTS transport system had high specificity for glucose since glucose transport was not significantly by a 100-fold molar excess of several competing sugar substrates, including 2-deoxyglucose and alpha-methylglucoside. These results demonstrate that S. mutans possesses a glucose transport system that can function independently of the PEP PTS.

Bacterial Proteins↗