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PubMed1989

Protection by F, I, Sr, and combinations against fermentation attack by Streptococcus sobrinus artificial plaque on bovine enamel.

Labial surfaces of 64 bovine incisors (8 teeth/treatment) were subjected to 1-min treatment with (1) 500 ppm Sr, (2) 0.5% I2 plus 1% KI solution, (3) F varnish treatment (Duraphat) for 24 h, or (4) combined treatments. The treated teeth were incubated under an artificial Streptococcus sobrinus plaque for 10 days. The 'oral fluid' with maleate buffer (pH 5.8) partially saturated with Ca3(PO4)2 and with or without 3.3% sucrose or sucrose plus 25 ppm F, was replaced by a mixture containing thioglycolate broth and the buffer for 4 h daily. This was done in an attempt to maintain the viability of the plaque as it was not renewed. Analysis of the Ca and inorganic P in the fluid phase taken after the 1st and the 10th day of incubation indicated that complete protection was obtained with F varnishing plus 25 ppm F in the fluid, with added sucrose. The Sr plus F treatment was more protective than F or Sr alone. The iodine treatment was slightly protective when combined with F varnishing. The results of the enamel surface and subsurface F and Sr as well as measurements of surface microhardness also indicated the highest protective effect with the double-F treatment and a marked protection provided by the Sr plus F treatment. The efficacy of the double-F treatment was partly explained by the prevention of a fall in 'plaque' pH and partly by the release of bacterial inorganic P in the extracellular fluid. The present caries model is versatile in quantification of changes in numerous parameters (14 parameters measured) involved in the caries-like process and its inhibition.

Acid Etching, Dental↗
PubMed1990

Phenytoin-induced gingival overgrowth in rats infected with Streptococcus sobrinus 6715.

Inbred Fischer rats were fed a high sucrose diet (No. 2000) containing phenytoin (5,5-diphenyl-hydantoin) for 52 days, which produced serum and salivary PHT levels of 13-14 and 2.6-2.7 micrograms/ml, respectively. Gingival overgrowth was induced in the molar region of all PHT-treated rats but was more severe in Streptococcus sobrinus 6715-infected rats than in non-infected rats, which had lower plaque scores. No significant overgrowth was found in rats infected with Strep. sobrinus and fed the same diet without PHT. Thus dental plaque accumulation enhanced, but was not essential for the development of the PHT-induced gingival overgrowth. Histological examination showed that the density of fibroblasts and connective tissue fibres was similar in all groups. This experimental model could serve as a useful means of understanding the pathogenesis of PHT-induced gingival overgrowth.

Animals↗
PubMed1987

Root surface caries subsequent to gingivectomy in rats inoculated with Streptococcus sobrinus (mutans) and Actinomyces viscosus.

We studied the effect of oral infection with cariogenic micro-organisms on alveolar bone loss and root surface caries subsequent to gingivectomy in rats. Thirty-six rats were fed diet MIT 200 (67% sucrose); one-half, the controls, had antibiotics added to the diet. At ages 18, 19, and 21 days, the experimental group was orally infected with streptomycin-resistant Streptococcus sobrinus (mutans) 6715 and Actinomyces viscosus M-100. At age 30 days, all animals were subjected to a gingivectomy on maxillary and mandibular left quadrants. The experimental group was re-inoculated at age 36 days. Animals were killed seven weeks after surgery. Jaws were stained, and planimetric measurements of exposed root surface area and caries on lingual/palatal surfaces of 1st and 2nd molars were made from video images with a computer/digitizer. Compared with the non-operated contralateral quadrants, gingivectomy significantly increased exposed root surface area in the maxilla and in the mandible in both the control and experimental groups. Oral inoculation significantly increased exposed root surface in mandibular (but not maxillary) quadrants which had received a gingivectomy, but had no effect on non-gingivectomized quadrants. There was no caries in the control group, whereas ten rats in the experimental group had root surface caries lesions, all in quadrants which had received a gingivectomy. This rat model should prove useful in further studies of root surface caries.

Actinomyces↗
PubMed1995

Glucosyltransferase from Streptococcus sobrinus Catalyzes Glucosylation of Catechin.

We previously showed that the polymeric forms of polyphenols present in oolong tea extract exhibited strong inhibitory activities against glucosyltransferases (GTases) of mutans streptococci, while green tea extract, which is rich in catechins, did not show such GTase-inhibitory activities. In this study, (+)-catechin [2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-3,5,7-triol] was found to be glucosylated by the GTase of Streptococcus sobrinus 6715 with sucrose as the substrate, and the product was identified as 4(prm1)-O-(alpha)-d-glucopyranosyl-(+)-catechin, with a molecular weight of 452. The (alpha)-glucosylated (+)-catechin did not exhibit significant inhibition of glucan synthesis from sucrose by the GTase, which is in contrast to the polymeric polyphenols isolated from oolong tea leaves.

Journal Article↗
PubMed1991

Inhibition of the growth of Streptococcus mutans, Streptococcus sobrinus and Lactobacillus casei by oral peroxidase systems in human saliva.

Streptococcus mutans, Strep. sobrinus and Lactobacillus casei were grown in glucose-supplemented, sterilized, human whole saliva, adjusted to pH 5, 6 or 7. Components of the antibacterial peroxidase system--hypothiocyanous acid (HOSCN) and hypothiocyanite ions (OSCN-)--were generated by adding exogenous H2O2 to sterilized saliva containing endogenous peroxidases and thiocyanate (SCN-) ions. HOSCN/OSCN- generation was proportional to the amount of H2O2 added, and more HOSCN/OSCN- was detected in saliva at pH 7 than at pH 5. However, the growth of mutans streptococci and L. casei was inhibited at pH 5 by HOSCN/OSCN-, whereas no inhibition was found at pH 7. The findings show that (a) sufficient amount of HOSCN/OSCN- will inhibit the growth of cariogenic bacteria in human saliva at pH 5; (b) this amount of HOSCN/OSCN- can be generated in saliva by exogenously added H2O2; and (c) peroxidase systems have stronger antistreptococcal effects in human whole saliva than in phosphate buffer.

Anti-Bacterial Agents↗
PubMed1993

Effects of xylitol/sorbitol combinations on bacterial growth and metabolism in Streptococcus sobrinus OMZ 176.

Combinations of the non-cariogenic sugar alcohols xylitol and sorbitol are widely used as sucrose substitutes in lozenges and chewing-gums. In S. sobrinus OMZ 176 xylitol inhibits the metabolism of sorbitol, and the xylitol-induced bacterial growth inhibition of S. sobrinus OMZ 176 has been shown to be enhanced by sorbitol. In combination with xylitol the sorbitol transport changes from a pts- to a non-pts transport, while the transport of xylitol is unaffected by the presence of sorbitol. It would be of interest to know how much xylitol has to be added to a sorbitol-containing medium to inhibit the metabolism of this sugar alcohol. In the present study no optimal inhibitory concentrations of xylitol/sorbitol combinations were found. Growth and acid production in S. sobrinus OMZ 176 are essentially the same for xylitol: sorbitol ratios in the range from 1:7 to 7:1. The presence of intracellular xylitol metabolites seems to be essential.

Carbon Radioisotopes↗
PubMed2005

Cranberry high molecular weight constituents promote Streptococcus sobrinus desorption from artificial biofilm.

Dental biofilm harbouring oral bacteria is highly correlated with the progression of dental diseases. Disruption of biofilm formation via anti-adhesion agents is an alternative means to the antibacterial approach. Previous studies have shown that high molecular weight non-dialysable material (NDM) derived from cranberry juice inhibits the adhesion of Escherichia coli and the coaggregation of a variety of oral bacteria. In addition, it inhibits the formation of glucans and fructans synthesised by GTF and FTF. In the present study, we examined the anti-adhesion effect of NDM on S. sobrinus. NDM promoted desorption of S. sobrinus from biofilm in the presence and absence of extracellular glucans and fructans, although the effect was more pronounced in the absence of these polysaccharides. Precoating of the bacteria with NDM reduced their ability to form biofilm. Our results indicate that NDM could be exploited as an anti-biofilm agent.

Bacterial Adhesion↗
PubMed1995

[Prevention of cariogenic dental plaque. Study of the structures implicated in the adhesion and coaggregation in Streptococcus mutans and Streptococcus sobrinus].

Cariogenic dental plaque may be assimilated to a biofilm resulting from the adhesion of S. mutans, then from the coaggregation of other streptococci, or other genus. We used a static monospecific biofilm model. Supports or bacteria were treated with inhibitors before adhesion in order to clarify the nature of adhesins responsible for the primary adhesion of S. mutans and S. sobrinus on Tygon. To determine the bindings of coaggregation, inhibitors were applied on one-day-old biofilms. Analysis of effects were performed by automatic inoculator Spiral (Interscience) for microbiological methods, and by SEM JEOL 5400 LV for microscopic methods. In the aim of preventing adhesion and coaggregation, different traps were assayed:sugars, chemical inhibitors such as F- and EDTA salts. Of these, only the latter showed efficiency. This confirmed the role of bivalent mineral ions and electrostatic attraction forces in the adhesion and coaggregation of streptococci.

Adhesins, Bacterial↗
PubMed1998

Ecological study of Streptococcus mutans, Streptococcus sobrinus and Lactobacillus spp. at sub-sites from approximal dental plaque from children.

Previous immunofluorescence (IF) studies have indicated that Streptococcus mutans may preferentially colonise specific sub-sites within approximal plaque. The present study aimed to extend these observations to other mutans streptococci and lactobacilli in such gingival margin plaque. Two hundred and seventy approximal plaque samples were taken from 90 teeth (3 from each tooth) in 64 children; three gingival margin sub-sites in relation to the contact area: away from (A), to the side of(S) and below (B) the contact area. Samples were processed by indirect IF using high-titred polyclonal anti-S. mutans 'c', anti-S. sobrinus 'd', anti-L. casei and anti-L. acidophilus antisera. An overall positive association was found between S. mutans 'c' and S. sobrinus 'd' (p < 0.001). Significant differences (p < 0.1) were found between the proportional counts at each sub-site for S. mutans 'c': A = 39%, S = 51% and B = 70%, and for S. sobrinus 'd' 21, 33 and 49%. Mutans streptococci (MS) appeared to preferentially colonise the sub-site below the contact area (B = 81%), compared with sub-sites A and S (48 and 62%, respectively). S. mutans 'c' and S. sobrinus 'd' were detected together at subsites A = 12%, S = 22%, and B = 38%, with proportional counts at B sites being higher than those at A (B > A, p < 0.01, and B > S, p < 0.05). Lactobacillus spp. were isolated rarely, and were usually found together with MS. There was a positive relationship between the presence of lactobacilli or MS and caries (white spot lesions only), although these species could frequently be isolated from noncarious sites. The presence of both S. mutans 'c' and S. sobrinus 'd' were strongly correlated with early caries lesions. In addition, this study confirmed the variation in the microflora at different sub-sites within approximal dental plaque.

Antibodies, Bacterial↗
PubMed1994

Subsite specificity of the active site of glucosyltransferases from Streptococcus sobrinus.

Oral bacterial glucosyltransferases use sucrose as a substrate in synthesis of either alpha-1,3 water-insoluble glucans (GTF-I) or alpha-1,6 water-soluble glucans (GTF-S). The binding specificity of the glucosyl and fructosyl subsites of the sucrose-binding site was examined to identify ligands that bind exclusively to each subsite. Such compounds can be used as reporter ligands to localize the subsite binding of any reversible or irreversible active site inhibitor. In examining potential subsite-specific ligands, binding affinity to GTF-I was consistently stronger than binding to GTF-S. Fructose was found to be a moderate GTF inhibitor, but free glucose, alpha-methylglucoside and glucose epimers were very weak inhibitors. In contrast, glucose transition-state analogues, D-glucano-1,5-lactone, 1-deoxynojirimycin (dNJ), and most N-alkyl derivatives of dNJ were moderate to strong inhibitors; in particular N-methyl-dNJ was found to be the strongest GTF inhibitor identified to date. Multiple inhibitor kinetic analysis established nonexclusive binding of fructose and dNJ at the respective subsites. Binding of fructose and N-alkyl-dNJ derivatives was, to a small degree, partially exclusive. Fructose and dNJ were used as reporter ligands to localize the subsite specificity of two test inhibitors: a reversible inhibitor, Zn2+, and an irreversible inhibitor, diethyl pyrocarbonate (DEP). Zn2+ paired with dNJ in multiple inhibitor kinetic analysis showed no competition between the inhibitors, while Zn2+ paired with fructose decreased ligand affinity 7-fold, establishing Zn2+ binding exclusively at the fructose subsite. Analogous experiments adapted to the irreversible inhibitor DEP indicated that it reacts at both subsites or induces a protein conformational change at one subsite that alters ligand binding at the adjacent subsite.

Binding Sites↗
PubMed1989

Associations between salivary levels of Streptococcus mutans, Streptococcus sobrinus, lactobacilli, and caries experience in Kenyan adolescents.

Salivary levels of mutans streptococci (S. mutans and S. sobrinus) and lactobacilli were determined in a random sample of rural Kenyans between 15 and 19 years of age (n = 149). It is possible for the natural history of dental caries in this population to be studied since it is characterized by a limited access to conventional dental treatment. Using a short set of biochemical tests, we identified from seven to ten presumptive mutans streptococcus colonies--cultured from the saliva of each individual--to differentiate between S. mutans and S. sobrinus. No colonies resembling S. rattus (S. mutans serotype b) were isolated. Lactobacilli were identified as Gram-positive, catalase-negative rods. The mean D1-4MFS and D3-4MFS were 7.03 +/- 6.43 and 1.46 +/- 3.44, respectively. The mean mutans streptococcus and lactobacillus levels were 8.7 x 10(4) and 6.7 x 10(4), respectively. The salivary mutans streptococcus and lactobacillus levels were significantly correlated (p less than 0.01). Of the subjects, 64% harbored only S. mutans, 4% only S. sobrinus, 30% both species, and 2% neither. Lactobacilli were ubiquitous. The caries experience of the group was significantly (p less than 0.001) correlated with both the total salivary level of mutans streptococci and the salivary S. mutans levels, but not with the salivary S. sobrinus level.

Adolescent↗
PubMed1990

Caries incidence in intact rats infected with Streptococcus sobrinus via transmission from desalivated cagemates.

The purpose of this study was to determine the influence of caging desalivated S. sobrinus-infected rats on the caries incidence in intact, previously uninfected cagemates. Weanlings were divided as follows: Stage I: Twenty desalivated animals paired with 20 intact animals (Group I); 20 intact animals paired with 20 intact animals (Group II). Animals were infected with S. sobrinus and fed diet 2000 and 10% sucrose water. After five weeks, ten paired animals from each group were killed. Desalivated animals had statistically higher (p less than 0.05) caries scores than did other animals. Stage II: The remaining Stage I infected animals from Groups I and II were paired with 40 new uninfected animals 15 days of age and fed cariogenic diets. After five weeks, new intact animals paired with Stage I desalivated animals had significantly higher smooth-surface enamel caries scores (38.0; SE 7.84) than new intact animals paired with Stage I intact animals (11.15; SE 3.69). Moreover, new intact animals caged for only five weeks with Stage I desalivated animals developed smooth-surface caries (38.0; SE 7.84) to a degree comparable with that in all Stage I intact animals in the experiment for ten weeks (36.6, SE 9.5; and 30.05, SE 4.1). The data suggest that desalivation may select a readily transmissible strain of S. sobrinus, which demonstrates enhanced virulence.

Animals↗
PubMedDate not supplied

Prevalence of Streptococcus sobrinus in relation to dental caries in children from Iceland and The Netherlands.

The aim of this study was to investigate the presence of S. sobrinus and S. mutans in specimens of dental plaque and saliva of children five years of age in Reykjavik, Iceland (study 1) and in samples of dental plaque from children nine years of age in Amsterdam, The Netherlands (study 2). The immuneblotting technique (IBT) was a suitable method to evaluate the presence and numbers of S. mutans and S. sobrinus in human dental plaque and saliva. In study 1, eighty-four children were evaluated bacteriologically; of these, 73 percent harbored mutans streptococci in their plaque or saliva. S. sobrinus similarly was present in 29 percent of the children. In study 2 (seventy-two children), the corresponding percentages were 81 percent for S. mutans, and 35 percent for S. sobrinus. The latter was detected in 6 percent of the plaque samples exclusive of S. mutans.

Child↗
PubMed1989

Cloning of the gene for cell-surface protein antigen A from Streptococcus sobrinus (serotype d).

A gene library of Strep. sobrinus B13N (serotype d) chromosomal DNA was constructed in Escherichia coli, with the bacteriophage vector lambda L47.1. A recombinant phage, lambda MDSM49, containing a 15.5 kb DNA insert, directed the expression of a 210 kDa antigenic protein. The recombinant 210 kDa protein was shown by Western blot analysis to be identical with cell-surface protein antigen A (spaA) from a serotype g strain. However, the restriction patterns of a subclone plasmid, pMD51, from lambda MDSM49 differed from those of serotype g strain. The cell-surface protein antigen I/II from serotype c Streptococcus mutans is a potential immunogen for vaccination against dental caries and corresponds to the spaA from serotype d and g strains. A recombinant clone, pDM51, will be a useful tool for serological and molecular biological studies. The recombinant spaA provides useful material for assessment of its diagnostic and immunogenic potential.

Antigens, Bacterial↗
PubMed1988

Combined effect of xylitol, NaF and ZnCl2 on growth and metabolism of Streptococcus sobrinus OMZ 176.

Xylitol, NaF and ZnCl2 in combination inhibited the growth of S. Sobrinus OMZ 176 when added to Brain Heart Infusion broth. Thin-layer chromatography, followed by autoradiography of cell extracts, was used to study the inhibiting mechanism. Glucose uptake was reduced, the glycolysis inhibited at the glucose 6-phosphate- and fructose- 1.6-diphosphate level and the accumulation of xylitol metabolites was increased. These effects in combination probably accounted for the inhibition of growth.

Biological Transport↗