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PubMed2006

Effect of MUC7 peptides on the growth of bacteria and on Streptococcus mutans biofilm.

OBJECTIVES: To investigate the susceptibility of selected bacteria as well as Streptococcus mutans biofilm to MUC7 peptides and compare the activities with those of other known antimicrobial peptides. METHODS: MIC and MBC of peptides for S. mutans, Escherichia coli, Streptococcus gordonii, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Pseudomonas aeruginosa were determined using the microdilution method. For S. mutans, the effects of the peptides on the kinetics of growth inhibition, time-killing, and on biofilm formation and reduction were also examined. For biofilm studies, polystyrene microtitre plates, Calgary Biofilm Device (CBD) and hydroxylapatite (HA) discs, along with Crystal Violet and Alamar Blue dyes, and/or EM observations, were employed. RESULTS: S. mutans was the most susceptible to all peptides tested (MICs of 9.4-25.0 microM), compared with the other species (MICs of 3.1->100 microM). MUC7 peptides (except MUC7-12-mer-L4) exerted 2-fold higher activity against S. mutans than Hsn5-12-mer and magainin-II, and faster killing of S. mutans than Hsn5-12-mer. The MUC7 peptides also had an effect on S. mutans biofilm. On the polystyrene plates, they suppressed the biofilm formation, with MBIC(50) of 6.25-12.5 microM, and reduced the 1 day developed biofilm in a batch culture, with MBRC(50) of 25-50 microM. On the CBD pegs, the viabilities of the biofilm were suppressed by >95% in the presence of MUC7 peptides at 4x MIC (50 microM). One day developed biofilm viabilities were inhibited by 49-75%. On HA, the formation of biofilm (as observed by EM) was also considerably reduced. CONCLUSIONS: MUC7 peptides present somewhat preferential antimicrobial activity against S. mutans. They also have an effect on in vitro formation and reduction of the preformed S. mutans biofilm.

Anti-Bacterial Agents↗
PubMed1987

Scanning electron microscopy of dentin caries. Experimental in vitro studies with Streptococcus mutans.

This study was performed to gain better insight into the mechanisms involved in carious destruction of human dentin by Streptococcus mutans. In particular, bacterial colonization of dentin surfaces and bacterial invasion in dentin were studied. Streptococcus mutans (S. mutans), strain NCTC 10449, was grown on sterile dentin blocks in a 10% CO2 atmosphere at 37 degrees C. After 72, 120, 144 and 288 h of incubation the specimens were processed for scanning electron microscopic examination. The colonization of the dentinal surface progressed slowly and was nearly complete after 288 h. Invasion of S. mutans into the dentinal tubules was found occasionally and was limited to the initial 5 micron of the tubular lumen. The acid metabolites produced by S. mutans, caused lesions of the dentinal structures in the close proximity of the bacteria. From the results of this in vitro study it appears that carious destruction of exposed dentinal surfaces by S. mutans mainly occurs at the exposed dentin after it has been colonized by bacteria. Destruction of the deeper dentinal layers by bacteria invading the dentinal tubules may play a less important role. However, in the few cases where S. mutans invaded the dentinal tubules, rapid destruction of the peritubular dentin sheath occurred. In addition, the possibility remains that acid metabolites produced by S. mutans diffuse into the dentinal tubules and cause tissue damage in the deeper parts of the dentin.

Dental Caries↗
PubMed1976

Ingestion of Streptococcus mutans induces secretory immunoglobulin A and caries immunity.

Ingestion of killed cells of a highly cariogenic strain of Streptococcus mutans induced specific antibodies in both saliva and milk but not in serum of gnotobiotic rats. These antibodies were associated with the immunoglobulin A class. When infected with Streptococcus mutans, orally immunized animals developed significantly fewer carious lesions than nonimmunized infected controls.

Administration, Oral↗
PubMed1989

Molecular cloning of the Streptococcus mutans gene specifying antigen A.

A gene encoding a Streptococcus mutans surface protein antigen has been isolated from a strain GS-5 gene bank constructed via the Streptococcus-Escherichia coli shuttle vector pSA3. This E. coli recombinant clone, designated 4B2, expressed S. mutans proteins, as shown by Western immunoblot analysis with a specific rabbit antibody to S. mutans surface antigens. Three bands were observed, including a 52-kilodalton (kDa) protein (pI 5.7), a 29-kDa protein (pI 4.2), and a 20-kDa protein usually present in lower amounts. The 52- and 29-kDa proteins both reacted with a monoclonal antibody to S. mutans antigen A, a 29-kDa protein which has been characterized and used as a vaccine for the prevention of induced caries in rodents and monkeys. The 52-kDa protein, but not the 29-kDa protein, showed a capacity to bind to a broad number of carbohydrate polymers. The results from this study suggest that the recombinant 4B2 clone specifies a 52-kDa protein which is a precursor to the 29-kDa antigen A.

Antibodies, Bacterial↗
PubMed2005

Dental caries experience and salivary levels of Streptococcus mutans and Lactobacilli in 13-15 years old children of Belgaum city, Karnataka.

The present cross-sectional study was carried out in 372 school going children of Belgaum aged 13-15 years. The sample was selected by two stage random sampling method. The aim of the study was to estimate the salivary levels of Streptococcus mutans and Lactobacilli and to study the relationship between these microorganisms and dental caries experience. The DMFT was recorded according to the WHO criteria(1997).The microbial load was estimated from a single saliva sample obtained from the children. The mean DMFT recorded was 2.41. Streptococcus mutans was detected in 87.37% and Lactobacilli in only 36.71% of the sample. Statistically, highly significant relation was found between Streptococcus mutans and DMFT categories (chi2=125.36, P<0.001), while Lactobacilli was not statistically related to DMFT categories (chi2=8.78, P>0.05).

Adolescent↗
PubMedDate not supplied

Antibacterial activity of polyphenol components in oolong tea extract against Streptococcus mutans.

The purpose of the present study was to determine the antibacterial activity of oolong tea extract on oral streptococci, including Streptococcus mutans and Streptococcus sobrinus, and to identify the response to its components. Antibacterial activity was found when the extract was added to S. mutans cells in chemically defined medium but not in complex broth media. Further, pretreatment with bovine serum albumin reduced the antibacterial activity. The extract showed antibacterial activity against all of the oral streptococci examined, with the highest activity against S. mutans MT8148R. This activity was found to originate from a monomeric polyphenol-rich fraction, and it was stronger than that of pure polyphenols. Moreover, some combinations of monomeric polyphenols showed the highest level of antibacterial activity. These results suggest that the antibacterial activity of oolong tea extract is caused by a synergistic effect of monomeric polyphenols, which can easily bind to proteins.

Animals↗
PubMed2000

Inhibition of Streptococcus mutans NS adhesion to glass with and without a salivary conditioning film by biosurfactant- releasing Streptococcus mitis strains.

The release of biosurfactants by adhering microorganisms as a defense mechanism against other colonizing strains on the same substratum surface has been described previously for probiotic bacteria in the urogenital tract, the intestines, and the oropharynx but not for microorganisms in the oral cavity. Two Streptococcus mitis strains (BA and BMS) released maximal amounts of biosurfactants when they were grown in the presence of sucrose and were harvested in the early stationary phase. The S. mitis biosurfactants reduced the surface tensions of aqueous solutions to about 30 to 40 mJ m(-2). Biochemical and physicochemical analyses revealed that the biosurfactants released were glycolipids. An acid-precipitated fraction was extremely surfactive and was identified as a rhamnolipidlike compound. In a parallel-plate flow chamber, the number of Streptococcus mutans NS cells adhering to glass with and without a salivary conditioning film in the presence of biosurfactant-releasing S. mitis BA and BMS (surface coverage, 1 to 4%) was significantly reduced compared with the number of S. mutans NS cells adhering to glass in the absence of S. mitis. S. mutans NS adhesion in the presence of non-biosurfactant-releasing S. mitis BA and BMS was not reduced at all. In addition, preadsorption of isolated S. mitis biosurfactants to glass drastically reduced the adhesion of S. mutans NS cells and the strength of their bonds to glass, as shown by the increased percentage of S. mutans NS cells detached by the passage of air bubbles through the flow chamber. Preadsorption of the acid-precipitated fraction inhibited S. mutans adhesion up to 80% in a dose-responsive manner. These observations indicate that S. mitis plays a protective role in the oral cavity and protects against colonization of saliva-coated surfaces by cariogenic S. mutans.

Bacterial Adhesion↗
PubMed1983

Analysis of cell wall and membrane contamination of ribosomal preparations from Streptococcus mutans.

A ribosomal preparation from a cariogenic strain of Streptococcus mutans was examined for cell wall and membrane contamination. A biochemical characterization established that the preparation contained 61.0% RNA and 39.0% protein. Carbohydrate was not detected by phenol-sulfuric acid or methyl pentose assays. Glucosyltransferase and D-succinate dehydrogenase, which are cell wall- and membrane-associated enzymes, respectively, were not found. However, D-lactate dehydrogenase, another membrane-associated enzyme, was present in the preparation. A comparison of two-dimensional gel electropherograms of a mixture of cell walls and membranes and the S. mutans ribosomal preparation revealed contamination of the latter sample with at least six cell wall- or membrane-associated proteins. Adsorption of a rabbit antiserum raised against the ribosomal preparation with whole S. mutans cells abrogated antibodies directed against at least two proteins from the ribosomal preparation. Immunodiffusion plates showed reactivity of this antiserum against preparations of purified lipoteichoic acid from Streptococcus pyogenes and S. mutans. Adsorption of rat and rabbit antisera against the ribosomal preparation with the cell wall-derived materials glucosyltransferase, lipoteichoic acid, glucan, and a Rantz-Randall extract reduced the concentration of antibodies against the ribosomes by as much as 10-fold. These data indicated that the preparation was contaminated with at least six cell wall proteins, one cell membrane-associated enzyme, and lipoteichoic acid.

Bacterial Proteins↗
PubMed1997

Tonsillar application of killed Streptococcus mutans induces specific antibodies in rabbit saliva and blood plasma without inducing a cross-reacting antibody to human cardiac muscle.

When Streptococcus mutans cells are injected into the skeletal muscle of rabbits, an antibody against human cardiac muscle, as well as an anti-S. mutans antibody, is induced in blood plasma. Our previous study showed that when sheep erythrocytes are applied to palatine tonsils, an antibody against the applied cells is induced both in blood plasma and saliva. This antibody has no activity against cardiac muscle. It is not clear, however, if S. mutans application to the tonsils evokes an antibody response against cardiac muscle. In this study, we immunized rabbits against S. mutans or Streptococcus sobrinus by tonsillar application or by intramuscular injection every 3 days for 6 weeks. Tonsillar applications of formalin-killed cells of S. mutans induced saliva immunoglobulin A (IgA) and blood plasma IgG to the applied cells. In contrast, intramuscular injection of such cells induced only blood plasma IgG. When the route of immunization was intramuscular injection, antibodies in blood plasma cross-reacted with cardiac muscle. By enzyme-immunohistochemistry and Ouchterlony immunodiffusion tests, no cross-reaction to cardiac muscle was observed with the antibody in saliva or in blood plasma after the tonsillar applications. Western blotting of the S. mutans antigen showed that blood plasma from rabbits injected with S. mutans reacted with antigens of 46, 52, 62, and 85 kDa, while that from rabbits subjected to tonsillar application of S. mutans did not react with these bands. Similar results were obtained for S. sobrinus applications. Thus, tonsillar applications of mutants group streptococci induce antibodies differing in antigen specificity and do not induce any cross-reacting antibody to cardiac muscle.

Animals↗
PubMed2004

Adherence of Streptococcus mutans to various restorative materials in a continuous flow system.

A continuous flow system was developed to evaluate the adhesion of Streptococcus mutans ATCC 25175 to filling materials (Ariston, Tetric, Dyract, Compoglass, Vitremer, Aqua Ionofil, Ketac Fil, amalgam, Galloy and ceramics as controls). Streptococcus mutans was added to saliva-coated test specimens, and a nutrient broth permanently supplied over a time period of 48 h and then the weight of plaque, the number and viability of the bacteria adhering to the materials were determined. The weights of artificial plaque on all filling materials tested were higher than those on ceramics, the highest values were measured on the glass-ionomers. The amount of plaque correlates with the surface roughness, whereas there was no correlation of the surface roughness with the number of colony-forming units (CFU) of S. mutans. The CFU of adhering S. mutans also depends on the viability of the bacteria. The plaque on Ketac Fil contained a high number of viable bacteria. The fluorides of glass-ionomers do not efficiently prevent the attachment and the viability of S. mutans.

Bacterial Adhesion↗
PubMed1976

Selective adsorption of heterophile polyglycerophosphate antigen from antigen extracts of Streptococcus mutans and other gram-positive bacteria.

Hot saline extracts of Streptococcus mutans have been shown to contain antigenic substances which occasionally react nonspecifically with some antisera against whole cells of various serological groups and types of streptococci. Chromatography of the extract of S. mutans strain MT703 (serotype e) on a diethylaminoethyl-Sephadex A-25 column gave two principal antigens. One antigen was eluted without adsorption to the resin and was identified as the serotype-specific polysaccharide. The other antigen, which contained a large quantity of phosphorus, was absorbed to and released from the resin by gradient elution. It was reactive against the antisera specific for polyglycerophosphate (PGP) from group A Streptococcus pyogenes and/or S. mutans strain Ingbritt (type c). The PGP antigen was further purified by gel filtration with Sephadex G-75. Two peaks, PGP-1, and PGP-2, were obtained. Each possessed the same antigenic specificity to anti-PGP serum as shown by immunodiffusion. Chemical analyses revealed that the molar ratio of phosphorus to glycerol in both was about 1:1, although the protein content between the two was significantly different. PGP antigen was found to be widely distributed in hot saline extracts from various gram-positive bacteria, with a few exceptions. However, all gram-negative bacteria examined were free of PGP. The PGP in the hot saline extracts of various gram-positive bacteria possessed an essentially identical antigenic specificity. The addition of diethylaminoethyl-Sephadex A-25 resin to hot saline extracts successfully removed the cross-reacting PGP antigen. After adsorption of the extract from S. mutans, the supernatant contained only type-specific polysaccharide antigen, except type b, in which both type b-specific polysaccharide and PGP antigens were absorbed with the resin. This simple procedure should be useful for the removal of the PGP-type teichoic acid from antigen extracts of bacteria that contain uncharged polysaccharides.

Antigens, Bacterial↗
PubMed1983

Effect of pH upon sucrose and glucose catabolism by the various genogroups of Streptococcus mutans.

Sucrose and glucose catabolism by seven strains of Streptococcus mutans belonging to six serotypes was assayed at pH's 6.5, 5.0, 4.5, and 4.0 with a radioisotopic tracer assay. The strains differed in their patterns of metabolic stimulation and inhibition at the different pH levels, falling into groups corresponding to the genetic groups described by Coykendall. The genogroup I (serotypes c and e) strains were the most acid-tolerant, having a pH optimum for lactic acid production at pH 5.0. These data furnish additional metabolic confirmation of the distinctiveness of these S. mutans subgroups.

Glucose↗
PubMed2004

[Expression of GBD gene of Streptococcus mutans glucan binding protein A in mammalian cells].

OBJECTIVE: To evaluate the expression of recombinant plasmid pcDNA3.1/GBD of glucan binding protein of Streptococcus mutans in mammalian cells COS-7. METHODS: Eukaryotic plasmid carrying encoding gene of GBD of Streptococcus mutans gbpA was constructed and the plasmid was introduced into COS-7 cells by Lipofectamine reagent. The transient expressed protein in COS-7 cells was detected by immunochemistry technique. RESULTS: The positive expression was detected in plasma of the cells which were transfected with recombinant plasmid pcDNA3.1/GBD. The cells which were transfected with pcDNA3.1 were negative. CONCLUSION: GBD can translate and express in COS-7 cells after transfected with recombinant plasmid pcDNA3.1/GBD. The expressed protein locates in the plasma and the protein is able to combine with anti-GbpA antibody. The expressed protein has the antigenicity and is a candidate gene vaccine.

Animals↗
PubMed1997

Thermophysiology of Streptococcus mutans and related lactic-acid bacteria.

The temperature ranges for growth of Streptococcus mutans GS-5 and S. sobrinus 6715 were found to be very narrow, from about 30 to 47 degrees C, with optimal growth around 37 degrees C. Thus, the organisms showed little potential to grow in the environment outside of the animal host. In contrast wider ranges were found for Enterococcus hirae, S. rattus and S. sanguis. Detailed study of S. mutans GS-5 showed that energetic coupling, reflected in yields of biomass per mol of glucose utilized, were not greatly affected by changes in temperature within the growth range. However, since glycolysis occurred over a wider temperature range (about 10 to 52 degrees C) than growth, yield values dropped to zero at temperatures above or below the growth range. The temperature range for glycolysis could be related to temperature sensitivity of the phosphoenolypyruvate: sugar phosphotransferase system for sugar uptake. F-ATPases were active over a similar range of temperatures, but with a broad optimal range from about 30 to 50 degrees C. Proton permeability of S. mutans increased steadily with temperature in a manner similar to that of other mesophilic bacteria, such as Escherichia coli. Growth of the bacteria in media supplemented with various fatty acids had major effects on proton permeabilities but the effects were not well reflected by changes in growth or glycolysis of the bacteria. The overall conclusions were that S. mutans is a typical mesophile in relation to membrane and catabolic functions but its narrow temperature range for growth is related to temperature sensitivities of anabolic systems.

Adenosine Triphosphatases↗
PubMed2005

Effect of a chlorhexidine varnish on Streptococcus mutans in saliva.

The aim of the present work was to evaluate the effect of a thymol/chlorhexidine varnish at 1% on Streptococcus mutans (S. mutans) in saliva applied after teaching and evaluating an oral hygiene technique and dressing the cavities to reduce the bacterial load. Streptococcus mutans levels in saliva samples and dental status were evaluated in 38 girls between 6 and 13 years of age with high risk of caries. The girls were then trained and assessed in oral hygiene. On day seven, oral hygiene assessment was repeated and supragingival plaque control was performed. After 15 days (day 21) another culture was performed and the level of S. mutans in saliva samples was determined. Evaluation and reinforcement of the oral hygiene technique were repeated and the cavities were dressed to reduce the bacterial load. At 36 days from the onset of the experiment, culture S. mutans counts were performed; evaluation and reinforcement of the oral hygiene technique were undertaken and the girls were divided randomly into two groups: 1 The teeth of the experimental group were painted with a varnish containing 1% chlorhexidine and thymol. 2 The teeth of the control group were painted with a placebo varnish containing only thymol. After a further 15 days (day 51), another culture and S. mutans counts were performed. The results showed a gradual reduction in the S. mutans counts in saliva in each subsequent experimental period analyzed. Significant differences between the experimental group and the control group were recorded after treatment. It can be concluded that the levels of S. mutans decreased in each subsequent experimental period and that the application of a 1% chlorhexidine varnish elicited a significant reduction in S. mutans levels.

Administration, Topical↗
PubMed2004

ComX activity of Streptococcus mutans growing in biofilms.

In many streptococci, including Streptococcus mutans, genetic competence is regulated by a quorum sensing system mediated by a competence stimulating peptide (CSP) pheromone, encoded by the comC gene. In Streptococcus pneumoniae, a central component of this system is ComX, which acts as an alternative sigma factor to activate competence genes involved in DNA uptake and processing. The quorum sensing system responsible for genetic competence induction in S. mutans has been linked to biofilm formation and the acid tolerance response. To examine the response of comX to CSP in S. mutans, a transcriptional fusion of the comX promoter (pcomX) with lacZ was constructed to generate reporter vector pcomx::pALH122 (replicative vector) and transformed into S. mutans UA159 comC-, which is unable to produce endogenous CSP. CSP was added and pcomX::lacZ relative expression index (REI) examined, revealing a 2-fold increase in maximal beta-gal activity 5 and 10 min after CSP addition. The effect of endogenous CSP on pcomX::lacZ expression was also examined by measuring REI in cells grown as a biofilm; peak pcomX activity was observed at 3 h. To determine the temporal pattern of transformation frequency, pMA2, a Spr shuttle vector, was transformed into biofilm-grown cells, with maximal transformation frequency observed at 3 h. Confocal microscopy was performed to examine pcomX activity using a similarly constructed green fluorescent protein reporter vector, pcomX::gfp, in a 4-h biofilm, revealing active pcomX activity in high cell density areas within the biofilm population. These results demonstrated a positive correlation between pcomX activity, natural transformation and competence development in biofilms.

Adaptation, Physiological↗
PubMed1978

Mechanism of glucan-induced agglutination in Streptococcus mutans. I. Binding of radioactive glucan to whole cells of S. mutans OMZ-176.

The binding of radioactive glucan to Streptococcus mutans cells, which are agglutinated by dextrans, was examined. The glucan was synthesized from sucrose by extracellular glucosyltransferases from S. mutans FA-1 and was highly branched at C-3 and C-6 of D-glucose residues, containing 17% of a (1 leads to 3)inter-chain residues. Binding of glucan to whole cells of S. mutans OMZ-176, which were agglutinated by addition of glucan or Dextran T2000, was irreversible and followed saturation type kinetics; saturation was achieved at approximately 110 ng of glucan per ml. About 14 ng of glucan were bound per mg of the cells at the saturated concentration. The heated cells of this organism, however, had a relatively low ability of glucan-binding, compared with the freshly prepared and lyophilized cells. Binding to the heated cells was entirely of a non-saturation type. Binding of Dextran T2000 or T10 was determined by competition between the labeled glucan and unlabeled Dextrans for the binding site(s). Both Dextrans and glucan from S. mutans FA-1 were bound to the same site(s). Other organisms, which did not undergo glucan- and Dextran-induced agglutination, had a relatively lower ability of glucan-binding than S. mutans, which was agglutinated.

Agglutination↗