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PubMed2002

Increased proliferative response of peripheral blood mononuclear cells and T cells to Streptococcus mutans and glucosyltransferase D antigens in the exacerbation stage of recurrent aphthous ulcerations.

BACKGROUND AND PURPOSE: Cytotoxic T lymphocyte-induced lysis of virus-infected oral epithelial cells has been shown to be a cause of early ulcer formation in recurrent aphthous ulcerations (RAU). To test whether bacteria and their associated antigens are involved in the disease process of RAU, the proliferative response (PR) to different streptococcal species in peripheral blood mononuclear cells (PBMC) and T cells isolated from RAU patients at the exacerbation stage was determined. METHODS: PBMC and T cells were isolated from 39 patients with RAU, 21 patients with erosive oral lichen plaus (EOLP, disease control group), and 22 healthy subjects (normal control group). Streptococcus mutans, Streptococcus sanguis, Streptococcus oralis, Streptococcus gordonii, Streptococcus mitis and their associated antigen, glucosyltransferase D (GtfD), were used to stimulate isolated PBMC and T cells in in vitro proliferation assays. RESULTS: PBMC and T cells isolated from RAU patients at the exacerbation stage showed a significantly higher PR to S. mutans antigen and GtfD than those isolated from EOLP patients or healthy control subjects (p < 0.05). GtfD was a more potent stimulation antigen than S. mutans. However, elevated PRs to S. mutans antigen and GtfD were transient and present only in the exacerbation stage of RAU. These elevated PRs declined to normal levels in the postexacerbation and convalescence stages of RAU. Furthermore, the GtfD-stimulated PR in PBMC and T cells was correlated with the severity of RAU. CONCLUSION: In addition to viral infections, streptococci and their associated antigen, GtfD, may be involved in the disease process of RAU, especially in the exacerbation stage.

Adolescent↗

PubMed1993

Identification of several rod loci and cloning of the rodD locus of Streptococcus mutans.

Previous work has shown that Streptococcus mutans is normally a short rod or a sphere, depending on its environment. This paper describes two distinct genetic approaches used to identify multiple loci and isolate one locus, rodD, controlling S. mutans rod shape. The first method involved isolation of a group of rod- mutants caused by transposon Tn916 insertion, and analysis of the inactivated genes by Southern hybridization. The second method involved mutagenesis via a shotgun insertion-duplication technique, isolation of a rod- mutant, and cloning the intact rod locus, employing an integration shuttle plasmid, pVA891. These approaches have led to the identification of multiple rod loci involved in determining the rod shape of S. mutans, and also cloning of one rod locus, rodD. The cloning strategy may also be useful for cloning other streptococcal genes which cannot be detected by their expression in Escherichia coli.

Blotting, Southern↗

PubMed1979

Nature of the fructan of Streptococcus mutans OMZ 176.

The fructan of Streptococcus mutans OMZ 176 was shown to have a levan structure by comparing the chromatographic mobilities of the saccharides produced by partial acid hydrolysis of ghe fructan and known levan and inulin. This was confirmed by using concanavalin A as a lectin in a double-diffusion gel technique.

Chemical Phenomena↗

PubMed2004

Isopanduratin A from Kaempferia pandurata as an active antibacterial agent against cariogenic Streptococcus mutans.

An antibacterial compound active against Streptococcus mutans was isolated from Kaempferia pandurata and identified as isopanduratin A using 1H NMR, 13C NMR and EI-MS. The minimum inhibitory concentration (MIC) of isopanduratin A was 4 mg/l which was much lower than that of some other natural anticariogenic agents such as sanguinarine (12 mg/l), green tea extract and carvacrol (125 mg/l), thymol (250 mg/l) and isoeugenol and eucalyptol (500 mg/l). The bactericidal test showed that isopanduratin A completely inactivated S. mutans at 20 mg/l in 1 min. Significant inhibitory activity of isopanduratin A was also observed against S. sobrinus, S. sanguinis and S. salivarius with an MIC of 4 mg/l. Damage to the cell membrane and cell wall of S. mutans by isopanduratin A was shown using transmission electron microscopy (TEM). These results suggest that isopanduratin A could be employed as a potential antibacterial agent for preventing dental caries.

Anti-Bacterial Agents↗

PubMed1997

Influence of heat inactivation of human serum on the opsonization of Streptococcus mutans.

Phagocytosis of bacteria, such as Streptococcus mutans, is important to host defense. One mechanism by which phagocytosis can be enhanced is by antibody or complement-mediated opsonization of bacteria. Many studies utilize opsonization of bacteria to enhance a cellular response, but little information has been found examining methodology or validity of the opsonization process following the denaturization of the serum. Human serum was inactivated by heat in order to disrupt the classical and alternative pathways of the complement cascade. S. mutans isolated from human subjects were opsonized with heat-inactivated human serum before exposing them to viable neutrophils in vitro. Luminol-dependent chemiluminescence (CL) was used to measure neutrophil activation. Human serum used to opsonize the bacteria was denatured by incubation at 57 degrees C for intervals of 30 and 60 min to inactivate complement. The results from the opsonization data indicated that there was significantly increased CL with 60-min inactivation of the serum (34% increase in mean integration mV.min; p < or = 0.05) over the nonopsonized control. This indicated a successful opsonization of the bacteria. In addition, the data demonstrate that the inactivation of serum requires a minimum of 60 min at 57 degrees C to disrupt the complement cascade, while 30- and 15-min inactivations produced no significant increase in CL activity over the control. Standard sandwich ELISA assays, detecting complement binding to S. mutans, confirmed successful heat inactivation of serum showing a significant decrease (p < or = 0.001) in complement binding to S. mutans after 30 min, but could not explain the increased CL response after 60-min heat deactivation of the serum.

Adult↗

PubMed1995

Mineralization of Streptococcus mutans in vitro. An ultrastructural study.

Streptococcus mutans mineralization was studied in vitro, with the use of various metastable calcium phosphate solutions, fluoride-containing or otherwise. Degeneration of bacteria always occurred before their mineralization. After complete mineralization of the cytoplasmic area, growth of crystals was observed both in length and in thickness within the extracellular environment. Composition of the calcifying medium was an essential factor in the S. mutans mineralization process. The present study shows that, contrary to carbonate and magnesium ions that prevent intra- and extracellular deposits, fluoride ions promote crystal growth in the above mentioned mediums. Clinical implications of the role of fluoride, at the plaque level, are foreseen.

Calcification, Physiologic↗

PubMed2004

Comparative analysis of Gtf isozyme production and diversity in isolates of Streptococcus mutans with different biofilm growth phenotypes.

Streptococcus mutans is the main pathogenic agent of dental caries. Glucosyltransferases (Gtfs) produced by these bacteria are important virulence factors because they catalyze the extracellular synthesis of glucans that are necessary for bacterial accumulation in the dental biofilm. The diversity of GtfB and GtfC isozymes was analyzed in 44 genotypes of S. mutans that showed a range of abilities to form biofilms in vitro. Several approaches were used to characterize these isozymes, including restriction fragment length polymorphism analysis of the gtfB and gtfC genes, zymographic analysis of the identified GtfB and GtfC genotypes, and quantitation of isozyme production in immunoblot experiments with specific monoclonal antibodies. A high diversity of gtf genes, patterns of enzymatic activity, and isozyme production was identified among the isolates tested. GtfC and, to a lesser extent, GtfB were produced in significantly higher amounts by strains that had high biofilm-forming ability than by strains with low biofilm-forming ability. Biofilm formation was independent of the GtfB and GtfC genotype. Atypical strains that showed an apparent single Gtf isozyme of intermediate size between GtfB and GtfC were also identified. The results indicate that various expression levels of GtfB and GtfC isozymes are associated with the ability of distinct S. mutans genotypes to grow as biofilms, strengthening the results of previous genetic and biochemical studies performed with laboratory strains. These studies also emphasize the need to identify factors that control gtf gene expression.

Bacterial Proteins↗

PubMed2002

Streptococcus mutans levels and caries prevalence in low-income schoolchildren.

Previous studies have shown that persons having high Streptococcus mutans levels in the saliva are "at risk" for dental caries. Most investigators agree, that if high levels of S. mutans were identified early in the life of at-risk children, dental decay could be reduced or eliminated through intervention. The purpose of this study is to show an association between S. mutans levels and caries prevalence in a sample of elementary school children. The study group consisted of 242 school children, ages 5-13 years. The subjects were divided into two age groups, 5-8 years and 9-13 years. Approximately 59 percent were African Americans. The sample of 242 children were equally females and males, 50 percent in each group. The Dentocult SM Test was used to make S. mutans determinations. The df-t index was used to determine the number of decayed and filled teeth of children ages 5-8 years; the DMF-T Index estimated the number of decayed, missing or filled teeth of children ages 9-13 years. Dental caries were found in 58 percent of the children (mean = 2.67, and range of 1-11). Approximately 47 percent of the children with caries had high S. mutans levels (100K-1M). Females had higher S. mutans levels than males in the 9-13 age group, p < .05. Analysis of Variance Test indicated that S. mutans levels for older females (ages 9-13) were significantly higher than those observed in males the same age (p < .01). This trend was not observed in younger children, ages 5-8 years. In addition, no significant difference or interaction was noted by sex for S. mutans levels and decayed or filled teeth (df-t) for younger children. We conclude that high levels of Streptococcus mutans are related to increased number of decayed teeth and conversely, low Streptococcus mutans levels are related to fewer dental caries. This study was supported in part by Colgate-Palmolive Company and the National Dental Association Foundation, Inc.

Adolescent↗

PubMedDate not supplied

Effect of salivary pellicle formation time on in vitro attachment and demineralization by Streptococcus mutans.

Enamel subsurface demineralization induced by Streptococcus mutans was significantly reduced by seven-day saliva pre-treatments conducive to the formation of enamel pellicles. A two-hour saliva pre-treatment was ineffective. Results suggest that the protection provided by long-term pellicles may relate to changes in ionic transport rates rather than cell attachment.

Adhesiveness↗

PubMed2002

Detection of potentially cariogenic strains of Streptococcus mutans using the polymerase chain reaction.

Streptococcus mutans is a pathogen related to the occurrence of human dental caries. The determination of total amounts of mutans streptococci, as well as the proportion related to other oral bacteria, is of interest when assessing the risk of developing caries. In this context, it is better to use a sensitive, specific and non-time consuming method such as the polymerase chain reaction (PCR), than to use culture and biochemical identification methods. In this work we identified potentially cariogenic strains of S. mutans and assessed the relationship with the dmft, DMFT or dmft/DMFT index. Using DNA isolated from dental plaque, a 192 bp sequence was identified and amplified from the spaP gene and a 722 bp sequence from the dexA gene. The results suggest that it is important to evaluate the presence of cariogenic S. mutans strains in plaque content rather than the accumulation of plaque itself However, other factors like diet, hygiene, genetic background, the flow rate of saliva and the presence of specific antibodies, also play a key role in the development of caries.

Bacterial Typing Techniques↗

PubMed1975

Relationship between cell-bound dextransucrase and the agglutination of Streptococcus mutans.

Dextran-induced agglutination of Streptococcus mutans cells is independent of cell-bound dextransucrase activity. Toluene extraction or the presence of Hg2+ or Cu2+ markedly decreased or completely abolished cell-bound dextransucrase activity without adversely affecting dextran-induced cell agglutination. Cells treated by heating at 100 C until cell-bound dextransucrase was completely inactivated continued to agglutinate when induced by dextran-induced cell agglutination resulted from cell treatment with trypsin and several other enzymes, as well as from ethylenediaminetetraacetic acid treatment, without a corresponding loss of cell-bound dextransucrase activity. Cells possessed a greater avidity for branched dextrans of low molecular weight than for linear dextrans of the same weight, indicating that size alone does not determine the efficiency of dextran as an inducer of agglutination. Divalent metal ions were required for both sucrose- and dextran-induced agglutination of S. mutans K1-R cells. Although normal cells of strain 6715-49 did not appear to require divalent cations for agglutination, heat- and ethlyenediaminetetraacetic acid-treated cells specifically required Ca2+. The role of Ca2+ in cell agglutination may be either to activate the cell-surface dextran receptor or to form specific intercellular Ca2+ bridges.

Agglutination↗

PubMed1988

Implantation and cariogenicity in hamsters of Streptococcus mutans with different hydrophobicity.

Strains of Streptococcus mutans with different surface hydrophobicity were examined for their ability to colonize and induce carious lesions in hamsters given a high sucrose diet. In a short-term experiment the hydrophobic strain GW showed almost an identical colonization pattern compared to the hydrophilic strain GW36. Streptomycin resistant variants of GW and GW36 implanted at a much slower rate than the parent strains. Differences in caries score were observed between the strains. The cariogenicity of the strains seemed to be dependent on early colonization.

Animals↗

PubMed1981

Detection and characterization of hemolysin production in Streptococcus mutans.

Beta-hemolytic strains of Streptococcus mutans were identified and physiological reactions and hemolysin production were studied. Strict anaerobic conditions were shown to be indispensable for the expression of beta-hemolysis on blood agar plates; hemolysis was only observed after growth in an atmosphere with an oxygen content of 10 ppm or lower. The occurrence of beta-hemolytic strains was found not to be restricted to one biotype of S. mutans. Two hemolytic activities were detected in liquid cultures. Oxygen-labile activity was detected in prereduced broth cultures and was shown to be unstable and indetectable in supernatants. Solubilization of oxygen-labile hemolysin was achieved by the addition of Tween 80 to the cultures. Oxygen-stable activity was detected in supernatants of cell suspensions in the presence of maltose, Casamino Acids, and Tween 80. In contrast to oxygen-labile activity, oxygen-stable activity was not detected in broth cultures.

Anaerobiosis↗

PubMed1975

Variation in internal polysaccharide synthesis among Streptococcus mutans strains.

Five strains, representative of Streptococcus mutans genetic group III antigenic group d, synthesized and degraded less intracellular polysaccharide (IPS) then 17 strains representative of other S. mutans groups. The strains that synthesize IPS degraded it rapidly. The production of acid in titratable amounts from endogenous IPS was usually complete within 1 h. IPS synthesis in S. mutans increased abruptly at culture glucose concentrations between 0.2 and 0.5% and was quantitated as both iodine-and glucose oxidase-positive material in cell hyrolysates. IPS degradation was measured by acid production in a pH-stat maintained at 7. The existence within group III d of a strain recently shown to be cariogenic in experimental animals suggest that IPS may not be a prerequisite for virulence in these cariogenic bacteria.

Acids↗

PubMed1982

Interference of Salivary immunoglobulin A antibodies and other salivary fractions with adherence of Streptococcus mutans to hydroxyapatite.

The adherence of Streptococcus mutans to hydroxyapatite was studied in the presence of salivary fractions with varying activity of naturally occurring immunoglobulin A (IgA) antibodies. Human parotid saliva from different donors was fractionated by chromatography and compared. Salivary IgA antibodies had no decisive effect on the adherence of the S. mutans strain used. High-molecular-weight salivary components from some subjects had an adherence-promoting effect, whereas fractions collected after the void volume of a Sepharose 2B column always inhibited adherence. The data indicate that the influence of unfractionated saliva on adherence is dependent on the net effect of adherence-promoting and adherence-inhibiting components. This principle has to be considered when the effect of human saliva on microbial adherence is studied.

Adhesiveness↗

PubMed1975

Analysis of growth rate in sucrose-supplemented cultures of Streptococcus mutans.

In the presence of sucrose, Streptococcus mutans grows in large glucan-containing aggregates. Because of reports of linear rather than exponential growth of sucrose-grown cultures, the kinetics of growth of sucrose-grown cultures of S. mutans strain OMZ-176 were compared with those of glucose-grown cultures. Culture turbidity measurements indicated that growth of sucrose cultures was slower, did not follow exponential kinetics, and slowed and stopped at lower absorbance values than did glucose-grown cultures. However, measurements of the rates of accumulation of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein using fully equilibrated radioactively labeled precursors of each of these macromolecular species in sucrose and glucose-grown cultures showed that: (i) for glucose cultures the synthesis of each of the three informational molecules occurred at the same exponential rate, which was identical to the rate of turbidity increase; (ii) for sucrose cultures each macromolecular species was synthesized at the same exponential rate and these rates were identical to the rate of increase of turbidity of the glucose-grown culture for periods of up to 7 h. Furthermore, the ratios of DNA to RNA, RNA to protein, and protein to DNA for the sucrose cultures were identical to those for the glucose cultures for up to 10 doublings. From these data it was concluded that in the presence of sucrose S. mutans grows in a balanced fashion at the same exponential rate as it does in glucose. The deviation from an exponential growth model of the absorbance in sucrose cultures was attributed to an optical artifact due to the formation of large glucan-containing aggregates of cells. The addition of dextranase to sucrose cultures resulted in cultures which increased in turbidity at the same exponential rate as glucose-grown cultures, without affecting the rate or extent of macromolecular synthesis.

Carbon Radioisotopes↗

PubMed1997

Identification of a frameshift mutation resulting in premature termination and loss of cell wall anchoring of the PAc antigen of Streptococcus mutans GS-5.

Most strains of Streptococcus mutans possess a 190-kDa protein antigen (PAc) on their cell surfaces, while strain GS-5 produces extracellularly a 155-kDa PAc protein. The pac gene of strain GS-5 consists of 3,477 bp and codes for a protein of 1,158 amino acids. One insertion of an adenine into the 3,469th, 3,470th, or 3,471st position from the start codon results in a frameshift mutation at codon 1157 with subsequent termination after 3 additional codons.

Amino Acid Sequence↗

PubMed1987

Erupting third molars and salivary lactobacilli and Streptococcus mutans counts.

The salivary lactobacilli and Streptococcus mutans counts in 217 university students of 25.4-yr-old were studied with regard to the state of eruption of their third molar teeth. Statistically significantly higher counts of both bacterial species were found in students who had one or more third molars partly erupted, compared with those whose third molars were lacking or fully erupted. No other parameters studied such as salivary flow rate or buffering capacity of the saliva were found to explain the high bacterial counts. These findings should be taken into consideration when interpreting salivary microbial counts in young adults. Also, special interest should be focused into these aspects at oral hygiene and dietary counseling of young patients.

Adult↗