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colonization and cariogenicity of streptococcus ferus in rats.streptococcus ferus, which is indigenous to wild rats, is a member of the mutans group of streptococci. we tested its ability to colonize and to cause caries in laboratory rats by comparing two strains of s. ferus with the very cariogenic streptococcus sobrinus strain 6715. groups of rats were fed either finely ground mouse chow or a 56% sucrose diet, or they were switched from chow to the sucrose diet. all three strains colonized the mouths of rats regardless of diet. however, the infectants re ...19817216496
dextran-induced aggregation in a mutant of streptococcus sobrinus 6715-13.a mutant of wild-type streptococcus sobrinus 6715-13 has been isolated which resists aggregation by exogenous dextran. this variant is able to form adherent plaque deposits in vitro when cultured in the presence of sucrose and has dextranase activity. in these respects it is the complement of previously described isolates which are plaque formation defective but aggregation normal. measurements of the incorporation of glucose from glucosyl-labeled sucrose into glucan by cell-associated glucosylt ...19836190754
immunoperoxidase labeling of streptococcus mutans for scanning electron microscopy.the application of an immunoperoxidase method to labeling of streptococcus mutans subsp. sobrinus for scanning electron microscopy is described. bacteria from four separate cultures were fixed in 2.5% buffered glutaraldehyde solution. the specimens were treated in accordance with an indirect immunolabeling procedure using a rabbit anti-s. mutans subsp. sobrinus gamma-globulin. labeled bacteria were equipped with a layer of small, distinct globules of horse-radish peroxidase reaction product. bac ...19836349231
prevalence, distribution of serotypes, and cariogenic potential in hamsters of mutans streptococci from elderly individuals.the prevalence of mutans streptococci (streptococcus mutans, streptococcus cricetus, streptococcus sobrinus, and streptococcus rattus) was determined in the salivas of 169 elderly individuals ranging in age from 60 to 87 years. approximately 40% of these individuals were edentulous and wore full upper and lower dentures. with the exception of a higher proportion of saliva counts below 1,000 cfu/ml in the full-denture wearers, the prevalence and the serotype and species distributions of the mutan ...19836874072
penicillin-induced lysis of streptococcus mutans.treatment of streptococcus mutans gs-5 cells with concentrations of penicillin g within a relatively narrow range resulted in substantial lysis. this penicillin-induced lysis was dependent upon cell density and ph of the lysis medium. other oral streptococci (streptococcus sobrinus, streptococcus rattus, and streptococcus cricetus) also demonstrated substantial levels of penicillin-induced lysis under appropriate conditions. lesser degrees of lysis were seen in a related organism, streptococcus ...19846500698
competitive displacement of mutans streptococci and inhibition of tooth decay by streptococcus salivarius tove-r.the ability of streptococcus salivarius tove-r to displace virulent representatives of the most prevalent human mutans streptococci from the teeth of rats, and thereby to inhibit caries, was studied. streptococcus mutans 10449s- or streptococcus sobrinus 6715-13wt-infected specific-pathogen-free rats consuming a high-sucrose diet were inoculated by tove-r. the infectants were differentially recovered from swabs of the teeth over the time course of infection and from sonically treated material of ...19853980093
structural studies of the rhamnose-glucose polysaccharide antigen from streptococcus sobrinus b13 and 6715-t2.the rhamnose-glucose polysaccharide antigens from the cell walls of streptococcus sobrinus b13 and 6715-t2 (formerly streptococcus mutans serotypes d and g, respectively) were structurally examined by using gas chromatography-mass spectroscopy. these data confirmed earlier chemical and serological studies suggesting that these polysaccharides had identical structures. the polysaccharides appeared to have a backbone of alternating 1,2- and 1,3-linked rhamnose units. branching occurred at 1,2,3-li ...19854055034
effects of chlorhexidine gluconate in drinking water on dental caries and oral microorganisms in the syrian hamster.hamsters infected with streptococcus sobrinus (formerly streptococcus mutans) strain 6715-1119 were given high-sucrose diet 2000. after 5 days, they were presented with 0.05 or 0.1 per cent w/v chlorhexidine gluconate (chx) continuously in their drinking water, which was well-tolerated. compared to infected but untreated controls, their caries scores were less by 84 and 97 per cent respectively after 42 days. coronal dental plaque deposits were reduced in a dose-related fashion. culture plates o ...19863307713
characterization of immune response to oral administration of streptococcus sobrinus ribosomal preparations in liposomes.gnotobiotic rats gastrically intubated with a total of 12.5 micrograms of streptococcus sobrinus ribosomal protein incorporated into cholesterol-based liposomes had significantly (p less than or equal to 0.01) fewer carious lesions on their molar surfaces than did nonimmunized infected controls after challenge with a virulent organism. the immunized animals had significantly (p less than or equal to 0.01) lower numbers of molar-adherent s. sobrinus cells and higher levels of salivary immunoglobu ...19863781625
in vitro studies of growth and competition between s. salivarius tove-r and mutans streptococci.streptococcus salivarius tove-r has previously been reported as a successful competitor with streptococcus mutans 10449s and streptococcus sobrinus 6715-13 wt on the teeth of rats. we studied, in vitro, some possible bases for this competition, including hydrogen peroxide or catalase production, bacteriocin or enocin production, and growth rates. growth rates were measured spectrophotometrically in both complex and defined media. we studied conditions of aerobic and anaerobic incubation; glucose ...19863461031
strains of streptococcus mutans and streptococcus sobrinus attach to different pellicle receptors.we compared the levels of adsorption of streptococcus mutans jbp and streptococcus sobrinus 6715 to experimental pellicles formed from unsupplemented and glucosyltransferase (gtf)-supplemented saliva. pellicles formed on hydroxyapatite beads from gtf or from saliva-gtf mixtures possessed detectable gtf activity. low levels of gtf activity were also detected in clarified whole human saliva, but not in samples of submandibular saliva. the adsorptive behavior of s. mutans jbp to pellicles formed fr ...19862422126
renaturation of dextranase activity from culture supernatant fluids of streptococcus sobrinus after sodium dodecylsulfate polyacrylamide gel electrophoresis.a rapid and reproducible method for the assay of individual fractions of the multicomponent dextranase activity of streptococcus sobrinus after reduction/denaturation and electrophoresis in acrylamide gels is described. multiple forms of dextranase, possible virulence factors in the formation of dental caries by oral streptococci (s. mutans, s. sobrinus, s. sanguis, s. cricetus, and s. rattus), have been separated in sodium dodecylsulfate-polyacrylamide gels into which an indicator substrate, bl ...19862433959
comparison of extracellular protein profiles of seven serotypes of mutans streptococci grown under controlled conditions.extracellular proteins produced by the four human commensal species of mutans streptococci were analysed. the organisms used were streptococcus mutans, serotypes c, e and f, streptococcus cricetus, serotype a, streptococcus rattus, serotype b, and streptococcus sobrinus, serotypes d and g. they were grown in continuous culture at different generation times and ph values in media containing either glucose or fructose to determine the extent of variation in extracellular protein production that co ...19862945902
monoclonal antibodies to the extracellular glucosyltransferases from streptococcus sobrinus 6715.murine monoclonal antibodies (mabs) were raised against the glucosyltransferases (gtfs) of streptococcus sobrinus 6715. the antibody panels included mabs raised against the primer-independent, soluble product enzyme (gtf-si) which did not cross-react with other gtfs, as well as mabs raised against the primer-dependent, soluble product enzyme (gtf-sd) which recognized both gtf-si and gtf-sd, thus indicating that these catalytically distinct enzymes share epitopes. mabs raised against gtf-i recogn ...19872956196
characterization of glucosyltransferase expressed from a streptococcus sobrinus gene cloned in escherichia coli.the gene encoding a glucosyltransferase which synthesized water-insoluble glucan, gtfi, previously cloned from streptococcus sobrinus strain mfe28 (mutans serotype h) into a bacteriophage lambda vector, was subcloned into the plasmid pbr322. the recombinant plasmid was stable in escherichia coli and gtfi was efficiently expressed. the gtf-i expressed in e. coli was compared to the corresponding enzymes in s. sobrinus strains mfe28 (serotype h), b13 (serotype d) and 6715 (serotype g) and shown to ...19872958599
oral immunization of humans with streptococcus sobrinus glucosyltransferase.the effect of oral administration of glucosyltransferase (gtf) from streptococcus sobrinus 6715 on levels of immunoglobulin a (iga) antibody to gtf in parotid saliva and on the number of indigenous streptococcus mutans in the whole saliva was studied in young adult males. gtf combined with aluminum phosphate (ap) was administered in capsules to 14 subjects, while sodium phosphate buffer combined with ap was administered in the same way to 11 control subjects. thirteen administrations were given ...19872959623
characterization by affinity electrophoresis of an alpha-1,6-glucan-binding protein from streptococcus sobrinus.glucan-binding protein 1 (gbp1), the most abundant glucan-binding protein isolated from culture supernatants of streptococcus sobrinus 6715-49, has been purified by affinity chromatography on sephadex g-50 followed by gel permeation chromatography with bio-gel p-10. the specificity and affinity of gbp1 for glucans were assessed by affinity electrophoresis. gbp1 did not detectably bind to glucans lacking linear arrays of alpha-1,6 linkages. the association constant for the linear alpha-1,6-glucan ...19872445685
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 m ...19873476557
effects of naf and snf2 on growth, acid and glucan production of several oral streptococci.the effects of low concentrations of these fluorides on streptococcus sobrinus, streptococcus mutans, streptococcus salivarius, streptococcus mitior and streptococcus sanguis were investigated. without fluoride, mutans streptococci (strep. mutans and strep. sobrinus) produced more acid than the other strains; both fluorides reduced acid production in all strains. naf had little effect on growth; snf2 decreased growth in all strains, most evidently in the strep. mutans. in all growth conditions, ...19873482350
haptenated streptococcal antigens elicit either t cell-dependent type 1 or t cell-independent type 2 immune responses.antigens of streptococcus mutans 6715 (alternatively designated serotype g streptococcus sobrinus), including whole cells (wc g), cell walls (cw g), peptidoglycan (pg g) and serotype carbohydrate (ml g) were coupled with trinitrophenyl (tnp), and the nature of the immune response to each immunogen was determined in normal and x-linked immunodeficient (xid) murine spleen cell cultures. responses to tnp-wc g, -cw g and -pg g and to the classical type 1 antigen tnp-brucella abortus occurred in both ...19873496265
protection of gnotobiotic rats against dental caries by passive immunization with bovine milk antibodies to streptococcus mutans.a multivalent vaccine consisting of whole cell antigens of seven strains, representing four serotypes (b, c, d and g), of mutans streptococci was used to hyperimmunize a group of cows. serum samples from these animals contained immunoglobulin g1 (igg1) antibody activity to seven serotypes (a to g) of mutans streptococci. whey obtained from the animal with the highest serum antibody activity, which also contained high levels of igg1 antibody, was used in passive caries immunity studies. gnotobiot ...19873498689
purification and partial characterization of the multicomponent dextranase complex of streptococcus sobrinus and cloning of the dextranase gene.the presence of proteases in culture supernatant fluids and on the cell surface of streptococcus sobrinus and the aggregation of multicomponent enzyme complexes make the isolation and characterization of cell surface proteins difficult. we report a simple purification procedure for dextranase and the cloning of the dextranase structural gene. s. sobrinus culture supernatant fluids were precipitated with 70% ammonium sulfate, and the precipitate was dialyzed against sodium acetate buffer and load ...19873546141
characterization of a rat salivary sialoglycoprotein complex which agglutinates streptococcus mutans.rat saliva agglutinated streptococcus mutans ingbritt and nctc 10449 and streptococcus sanguis nctc 7864 but not s. mutans nctc 10921, gs 5, or lm 7, streptococcus sobrinus 6715-13 or omz 65, or streptococcus cricetus hs 6, as measured turbidometrically. the specificity of agglutination by rat saliva was the same as that by human saliva. agglutination was associated with a mucin complex (rat salivary agglutinin complex [rs-a]) of sulfated sialoglycoproteins, with a trace of associated lipid and ...19873570462
effect of growth conditions on levels of components of the phosphoenolpyruvate:sugar phosphotransferase system in streptococcus mutans and streptococcus sobrinus grown in continuous culture.the membrane-bound, sugar-specific enzyme ii (eii) component of the phosphoenolpyruvate:sugar phosphotransferase system (pts) in streptococcus mutans ingbritt is repressed by growth on glucose under various conditions in continuous culture. compared with optimal pts conditions (i.e., glucose limitation, dilution rate [d] of 0.1 h-1, and ph 7.0), eii activity for glucose (eiiglc) and mannose (eiiman) in cells grown at a d of 0.4 h-1 and ph 5.5 with the same glucose concentration was reduced 24- t ...19873680174
effects of bicarbonate-based dental powder, fluoride, and saccharin on dental caries and on streptococcus sobrinus recoveries in rats.the effects of nahco3-based dental powder containing naf and sodium saccharin on dental caries and streptococcus sobrinus recoveries in rats were studied. weanling specific-pathogen-free osborne-mendel (spfom) rats were inoculated with s. sobrinus 6715-13wt. one of six infected groups was topically treated with either demineralized water (dw), a dental powder suspended such that there was 1 part solid per 2 parts dw, 0.073% naf, 0.5% na-saccharin (nas), or a combination of naf and nas at the sam ...19873038976
nucleotide sequence of a glucosyltransferase gene from streptococcus sobrinus mfe28.the complete nucleotide sequence was determined for the streptococcus sobrinus mfe28 gtfi gene, which encodes a glucosyltransferase that produces an insoluble glucan product. a single open reading frame encodes a mature glucosyltransferase protein of 1,559 amino acids (mr, 172,983) and a signal peptide of 38 amino acids. in the c-terminal one-third of the protein there are six repeating units containing 35 amino acids of partial homology and two repeating units containing 48 amino acids of compl ...19873040686
identification of streptococcus sobrinus with monoclonal antibodies.identification of streptococcus sobrinus is often difficult to perform because of the great resemblance of the organism to other oral streptococcal species. therefore, monoclonal antibodies were prepared which were shown to be highly specific for s. sobrinus. cross-reactivity with other oral microorganisms has not been observed in an enzyme-linked immunosorbent assay and an immunofluorescence assay. these monoclonal antibodies belonged to the subclass immunoglobulin g2b. to be certain that the s ...19873323224
two functionally different glucose phosphotransferase transport systems in streptococcus mutans and streptococcus sobrinus. 19872853322
effect of nutritional constraints on the biosynthesis of the components of the phosphoenolpyruvate: sugar phosphotransferase system in a fresh isolate of streptococcus mutans.a procedure for the purification of enzyme i (ei) and the protein hpr, the general components of the phosphoenolpyruvate:sugar phosphotransferase system, from streptococcus mutans serotype c is presented. the method was also applied successfully to the purification of ei and hpr from streptococcus salivarius, streptococcus sobrinus, and streptococcus sanguis. using specific antibodies obtained against the proteins purified from s. mutans dr0001, we determined quantitatively by rocket electrophor ...19883338847
c31g, a new agent for oral use with potent antimicrobial and antiadherence properties.c31g, an equimolar mixture of alkyl dimethyl glycine and alkyl dimethyl amine oxide, was evaluated for antimicrobial and antiadherence properties. the efficacy of c31g, its two components, and several commercial mouth rinses was determined in assays measuring inhibition of glycolysis, inhibition of bacterial adherence, and mics. inhibition of glycolysis was determined by using a saliva sediment model, with glycolytic activity expressed as the change in ph relative to that of a control. adherence ...19883364952
specificity of the glucan-binding lectin of streptococcus cricetus.the specificity of the glucan-binding lectin (gbl) of streptococcus cricetus aht was determined. examination of the kinetics of aggregation of cell suspensions with glucans containing various percentages of alpha-1,6, alpha-1,4, alpha-1,3, and alpha-1,2 anomeric linkages revealed that only glucans with at least 80% alpha-1,6 linkages promoted strong aggregation. moreover, only linear glucans with molecular weights greater than 5 x 10(5) were capable of causing rapid aggregation of the bacteria. ...19883397177
molecular cloning and expression of a streptococcus mutans major surface protein antigen, p1 (i/ii), in escherichia coli.antigen p1, also called i/ii, is one of the most abundant cell wall proteins of the mutans streptococci. it has been suggested that p1 may be involved in cell adherence to tooth surfaces and in sucrose-induced cell aggregation. as a first step toward fully understanding its biological functions, the p1 gene, which has been designated spap1, from streptococcus mutans ng5 (serotype c) has been cloned into escherichia coli jm109 by a shotgun procedure with puc18 as the vector. the recombinant strai ...19883135272
chemical and structural studies of serotype polysaccharide antigens of streptococcus sobrinus 6715.the g antigen of streptococcus sobrinus 6715 was previously shown to consist of polysaccharides of various molecular weights. in this study, two such polysaccharides, lii and liii, were purified by gel filtration and affinity chromatography procedures. by a double immunodiffusion analysis, fraction lii was found to contain a region in the serotype-specific g site not present in the serospecific g site of fraction liii. this region was designated x. in addition to the serotype-specific g site, th ...19883139566
suppression of streptococcus sobrinus 6715 (g) in plaques by streptococcus mutans 32k (c).the dental plaque of 96 healthy donors was screened for the production of such antibacterial substances as mutalipocin and bacteriocin and 192 strains of mutans streptococci isolated: 28 produced mutalipocin and 22 produced bacteriocin. mutalipocin produced by these 28 s. mutans strains possessed similar biochemical and biological characteristics of well-characterized mutalipocin-producing strain s. mutans 32k (serotype c). when equal amounts of s. mutans 32k and s. sobrinus 6715 (g) were cultur ...19883150434
synergistic antibacterial effects of copper and hexetidine against streptococcus sobrinus and streptococcus sanguis.the aim of this study was to determine whether a combination of copper and hexetidine had a synergistic antibacterial effect against streptococcus sobrinus omz 176 and s. sanguis 10556. concentration ranges of the test agents alone and in combination were prepared by serial dilutions in microtiter trays with brain-heart infusion (bhi) broth as the bacterial growth medium. after incubation at 37 degrees c for 24 h, the minimum inhibitory concentration (mic), corresponding to the lowest concentrat ...19883165588
in-vitro adherence of oral streptococci in the presence of sucrose and its relationship to cariogenicity in the rat.streptococcus sanguis i gave a significantly greater percentage coverage (cell-pellicle attachment) of saliva-coated glass in the presence of sucrose than did strep. sanguis ii (p less than 0.025), and both these gave greater percentage coverages than the other species tested, between which no significant differences were noted. there was a large number of significant differences in clump size (cell-cell attachment) between species-pairs. among the mutans streptococci, there were significant dif ...19883166609
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.19883166805
influence of desalivation in rats on incidence of caries in intact cagemates.the evidence that dental caries is an infectious and transmitted disease in rodents is unequivocal. however, the factors controlling the transmission of micro-organisms from one animal to another have not been extensively explored. results from previous studies in our laboratory showed that desalivated animals became infected by streptococcus sobrinus in a shorter period of time than did intact animals. furthermore, an additional study in our laboratory showed that animals with intact salivary f ...19883170887
the effects of different levels of dietary sucrose on root caries subsequent to gingivectomy in conventional rats infected with actinomyces viscosus m-100.three groups of weanling, sprague-dawley-derived rats were inoculated with actinomyces viscosus m-100 and fed powdered diet containing either 67%, 5%, or 0% confectioner's sugar. two further groups were fed diet containing 5% confectioner's sugar and inoculated with streptococcus sobrinus 6715 or s. sobrinus 6715 plus a. viscosus m-100. the most coronal 1 mm of gingiva was removed from maxillary and mandibular right molar quadrants (gingivectomy), and the animals re-inoculated following gingivec ...19883170889
the in vitro dental plaque inhibitory properties of a series of n-[1-alkyl-4(1h)-pyridinylidene]alkylamines.a series of novel n-[1-alkyl-4(1h)-pyridinylidene]alkylamine hydrohalides has been prepared and evaluated as inhibitors of dental plaque formation, in vitro. several members of the series exhibited potency ca. 9-fold greater than that of chlorhexidine vs streptococcus sobrinus 6715-13. the di-n-octyl analogue, 11 (pirtenidine), was found to be highly efficacious against several other oral plaque-forming microorganisms and is presently undergoing preclinical evaluation.19883172139
utilization of a continuous streptococcal surface to measure interbacterial adherence in vitro and in vivo.cell-to-cell interactions are essential for the formation of dental plaque. a continuous layer of streptococcus sanguis sa-1 cells fixed to a solid surface has been used to evaluate interactions among this bacterium, haemophilus parainfluenzae, and streptococcus sobrinus. s. sanguis cells were attached to a falcon 3001 tissue culture plates or bovine enamel chips, coated with a biological adhesive. scanning electron microscopy of the chips showed the streptococci as a contiguous surface. radiola ...19883198842
colonization of rat molar teeth by mutans streptococci with different salivary agglutination characteristics.the oral implantation of salivary agglutination-positive and -negative mutans streptococci was studied using streptomycin resistant (strr) organisms. strr streptococcus mutans strains ingbritt and nctc 10449 are agglutinated by rat saliva and the strr strains streptococcus sobrinus 6715-13 and strep. mutans gs5 are not. four groups of sprague-dawley rats were inoculated orally with each organism (one per group) and fed a sucrose diet. a further two groups of animals were similarly inoculated wit ...19883252771
prevalence of mutans streptococci and lactobacilli in elderly swedish individuals.the number of streptococcus mutans, streptococcus sobrinus, and lactobacilli in stimulated whole saliva was examined in 149 elderly persons. more than 10(6) cfu/ml of mutans streptococci were found in 57% of the subjects and 85% had more than 10(5) lactobacilli per ml of saliva. there was no difference in the prevalence of mutans streptococci between edentulous and dentate subjects whereas significantly more lactobacilli were detected in denture wearers. s. mutans was most frequent and was found ...19883277259
avirulent salmonella typhimurium delta cya delta crp oral vaccine strains expressing a streptococcal colonization and virulence antigen.salmonella typhimurium sr-11 strains lacking adenylate cyclase and the cyclic amp receptor protein (crp) due to deletion (delta) mutations in the cya and crp genes, respectively, are avirulent for mice and induce high level protective immunity against subsequent challenge with wild-type virulent s. typhimurium sr-11 cells. the avirulence of these delta cya delta crp mutants has been enhanced by elimination of the 100 kb virulence plasmid pstsr100 without impairing immunogenicity. the present rep ...19883291452
isolation of a glucan-binding domain of glucosyltransferase (1,6-alpha-glucan synthase) from streptococcus sobrinus.a glucan-binding domain of 1,6-alpha-glucan synthase (dextransucrase) (gtf-s) was isolated from a trypsin digest of the streptococcus sobrinus enzyme. the large 60.5-kilodalton peptide had an affinity for dextran comparable to that of the native enzyme, but had no glucan synthesis activity. the domain was produced in high yield compared with other large cleavage products, which allowed easy purification by size exclusion high-pressure liquid chromatography and affinity chromatography. two other ...19882964413
homology of glucosyltransferase gene and protein sequences from streptococcus sobrinus and streptococcus mutans.the sequences of glucosyltransferase genes from streptococcus sobrinus (gtfi) and streptococcus mutans (gftb) were compared and show a high degree of homology. there is a 57.7% homology of nucleotides in the genes and a 56.7% homology of amino acids in the deduced protein sequences. the g + c content for the protein-coding region is 43.6% for s. sobrinus and 41.2% for s. mutans. internal repeating sequences present in both proteins exhibit some difference in sequence pattern.19882971696
the caries inhibitory effects of gos-sugar in vitro and in rat experiments.the caries inhibitory activity of gos-sugar (panose- and maltose-rich sugar mixture) was examined and compared with that of sucrose, maltose, or glucose in in vitro and in vivo experiments. streptococcus mutans mt8148r (serotype c) and streptococcus sobrinus 6715 (g) did ferment gos-sugar and produce acid in a similar way as with maltose and glucose. however, gos-sugar could not be a substrate for the glucosyltransferases (gtases) of these mutans streptococci to synthesize the water-insoluble gl ...19882975747
reduction of the adherence of streptococcus sobrinus insoluble alpha-d-glucan by endo-(1----3)-alpha-d-glucanase.insoluble alpha-d-glucan, previously formed on a glass surface from sucrose by the action of cell-free d-glucosyltransferases of streptococcus sobrinus omz176, was significantly removed by a purified preparation of endo-(1----3)-alpha-d-glucanase (mutanase) from a strain of pseudomonas sp. almost complete dissociation of adherent glucan occurred at the highest enzyme concentration (40 mu/ml) tested. synthesis and de novo adherence on glass of the glucan was markedly inhibited by the presence of ...19882977294
genetic characterization of the spaa1 determinant of the surface protein antigen gene from streptococcus sobrinus 6715.1. the surface protein antigen-encoding gene spaa1, previously cloned from streptococcus sobrinus 6715 (serotype g) into the plasmid pacyc184, was examined. 2. the gene product of pya726 was identified both by the minicell method and by in vitro transcription-translation system as a protein whose mol. wt was estimated to be 140,000. 3. the spaa1 gene was localized on the 3.75 kb avai-bamhi fragment of the cloned dna. 4. an internal spaa1 promoter located close to one end of the 1.25 kb avai frag ...19892482205
[changes of antibody and splenic plaque forming cell responses to mutans streptococci in the rats infected with s. sobrinus 6715].the study was undertaken to examine the changes in humoral igm, igg and iga antibodies and splenic plaque forming cell responses against streptococcus sobrinus 6715 in rats infected with the same mutans streptococci. the serum samples were collected every week for 24 weeks after infection (20 day old, sprague dawley rats). humoral anti-s. sobrinus 6715 igg and iga antibodies were determined by an enzyme-linked immunosorbent assay. in the separate experiment, rat splenic igm, igg and iga anti-tri ...19892489371
[caries-inducing activity of isomaltooligosugar (imos) in in vitro and rat experiments].the caries-inducing activity of isomaltooligosugar (imos: a isomaltose rich sugar mixture) was examined in in vitro and in vivo experiments. strains of streptococcus mutans mt8148r and streptococcus sobrinus 6715 fermented imos and produced acids. imos inhibited the glucan synthesis from sucrose by glucosyltransferases from both of s. mutans and s. sobrinus. furthermore, imos inhibited sucrose-dependent adherence of those mutans streptococci. imos was found to induce significant but minimal cari ...19892489886
sucrose 6-alpha-d-glucosyltransferase from streptococcus sobrinus: characterization of a glucosyl-enzyme complex.a covalent glucosyl-enzyme was isolated from a quenched reaction of streptococcus sobrinus sucrose 6-alpha-d-glucosyltransferase and radiolabeled sucrose. no complex was observed with heat-inactivated enzyme or when sucrose was replaced with radiolabeled maltose or glucose. the complex was stable at ph 2 in 1% sodium dodecyl sulfate, 6.0 m urea, and 4.0 m guanidine hydrochloride, but became increasingly labile with increased ph (32-min half-life at ph 7.0). d-glucose was the exclusive radiolabel ...19892523727
use of 13c-n.m.r. spectroscopy for the quantitative estimation of 3-o- and 3,6-di-o-substituted d-glucopyranosyl residues in alpha-d-glucans formed by the d-glucosyltransferases of streptococcus sobrinus.the 13c-n.m.r. spectra of the three alpha-d-glucans from streptococcus sobrinus and the dextran from leuconostoc mesenteroides, which differ widely in the ratios of omega (terminal, nonreducing) d-glucopyranosyl groups: 3-:6-:3,6-linked d-glucopyranosyl (glc) residues, were measured in 0.5m naoh at 22 degrees. the c-1 signals of 3-o-substituted glc in a linear sequence, 6-o-substituted glc in a linear sequence, 3,6-di-o-substituted glc in a (1----6)-linked sequence, and glc attached to o-3 of 3, ...19892525070
glucan-binding domain of a glucosyltransferase from streptococcus sobrinus: isolation of a 55-kilodalton peptide from a trypsin digest of glucosyltransferase prebound to insoluble glucan.we isolated a glucan-binding domain of water-insoluble glucan synthase (gtf-i) of streptococcus sobrinus b13. mild trypsin digestion of gtf-i bound to a water-insoluble glucan (ig) produced one predominant large fragment (55 kilodaltons). the fragment was easily recovered in ig precipitate. the isolated fragment had the same degree of affinity to ig as did the native gtf-i but no glucan synthesis activity. by the same method, a similar 55-kilodalton fragment was protected for gtf-sd but not for ...19892525114
inhibition by maltose, isomaltose, and nigerose of the synthesis of high-molecular-weight d-glucans by the d-glucosyltransferases of streptococcus sobrinus.two d-glucosyltransferases are produced by streptococcus sobrinus c211. one (gtf-s) catalyzes the conversion of sucrose into soluble alpha-(1----6)-linked alpha-(1----3)-branched d-glucans, and the other (gtf-i), of sucrose into alpha-(1----3)-linked alpha-(1----6)-branched d-glucans. these enzymes were studied by using maltose, isomaltose, and nigerose as inhibitors. maltose and isomaltose were found to be competitive inhibitors of gtf-s, whereas nigerose has no effect on gtf-s activity. the ki ...19892526680
purification of a fourth glucosyltransferase from streptococcus sobrinus.recently, we found a novel primer-independent, water-soluble glucan synthase as a fourth glucosyltransferase (gtf) in a culture supernatant of strain aht-k of streptococcus sobrinus (y. yamashita, n. hanada, and t. takehara, biochem. biophys. res. commun. 150:687-693, 1988). in the present study, four kinds of purified gtfs, including the novel gtf, were prepared. they were composed of two primer-dependent gtfs and two primer-independent gtfs. of the primer-dependent gtfs, one was a water-insolu ...19892530209
effect of magnesium ions on secretion of glucosyltransferase from streptococcus sobrinus.magnesium ions, which are known to inhibit the leader peptidase (signal peptidase) activity of escherichia coli, stimulated the activities of glucosyltransferases (gtfs) in culture medium of streptococcus sobrinus at concentrations of 1 or 5 mm. at a concentration of 50 mm, the activity of water-soluble glucan synthase was not affected and that of water-insoluble glucan synthase was slightly suppressed. the activities of both gtfs in the crude enzyme extract were totally unaffected by addition o ...19892533315
glucosyltransferases of streptococcus sobrinus c211 are both stimulated and inhibited by hydrogen peroxide.there are 2 glucosyltransferases (gtf) produced by streptococcus sobrinus c211. one enzyme, gtf-s, produces a water-soluble glucan that is a-1,6-linked, with short a-1,3 branches, and the other enzyme, gtf-i, produces a water-insoluble glucan that is a-1,3-linked with a-1,6 branches. hydrogen peroxide was found not only to be a potent inhibitor of gtf activity, but also a stimulator of gtf activity when employed at relatively low concentrations. at 0.88 m, h2o2 completely inhibited insoluble glu ...19892534763
effect of several resin monomers on water insoluble glucan formation by glucosyltransferase of streptococcus sobrinus.the cause or mechanism by which more plaque tend to accumulate on composite resins than on any other restorative materials has yet to be sufficiently explained. the purpose of this study was to investigate a possible mechanism by clarifying the effects of several monomers on the glucosyltransferase activity from streptococcus sobrinus. the following results were obtained. in the individual resin monomers, di-, tri- and tetra-ethylene glycol dimethacrylate (2g, 3g and 4g), bis-gma and udma showed ...19892535160
inhibitory effects of humic acid on insoluble glucan synthesis and cellular adherence of streptococcus mutans (sobrinus) 6715. 19892535262
molecular and immunochemical characterization of recombinant escherichia coli containing the spaa gene region of streptococcus sobrinus.we identified and characterized a recombinant escherichia coli containing the entire gene for surface protein antigen a (spaa) of streptococcus sobrinus 6715. the recombinant e. coli was isolated from a cosmid gene bank of size-fractionated s. sobrinus dna fragments, and recombinants expressing the spaa protein were detected immunologically. subcloning experiments showed that the dna sequences encoding the spaa protein could be isolated on two contiguous ecori fragments, 3.7 and 3.3 kilobases (k ...19892543627
isolation and characterization of the streptococcus mutans gtfd gene, coding for primer-dependent soluble glucan synthesis.two glucosyltransferase genes from streptococcus mutans gs-5, gtfb and gtfc, have been previously isolated and sequenced in this laboratory. in the present communication a third gtf gene, gtfd, was isolated and characterized. isolation of the gene involved a novel procedure utilizing the integration plasmid pva891. a peptide expressed by the 1.7-kilobase dna fragment from strain nhs1 (containing deletions in both the gtfb and gtfc genes) was initially identified in a puc18 clone bank with antigl ...19892543630
dna homology of surface protein antigen a gene in mutans streptococci.1. a recombinant plasmid, pya724, containing an 8.45 kb dna fragment encoding surface protein antigen a (spaa) from streptococcus sobrinus 6715 was used to examine the dna homology of the spaa gene with chromosomal dna of various mutans streptococci strains. 2. restriction endonuclease bamhi-digested pya724 dna was radio-labeled by nick-translation, and a dna-dna hybridization experiment was carried out. pya724 dna hybridized with chromosomal dna of serotypes a, c, d, e, f and g strains, but not ...19892591635
the influence of saliva on infection of the human mouth by mutans streptococci.the relationship between oral implantation of streptococcus mutans ib1600 (serotype c) and streptococcus sobrinus omz65 (serotype g), the aggregating activity of saliva, and its influence on the adherence of these bacterial strains in vitro was examined in seven human subjects. all the saliva samples aggregated strain ib1600 but not strain omz65 cells. whole saliva from subjects with low levels of infection by strep. mutans aggregated strain ib1600 to a greater degree than did whole saliva from ...19892597028
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 lambd ...19892597046
caries on root surfaces exposed following gingivectomy in conventional rats infected with streptococcus sobrinus and actinomyces viscosus.to study the ability of bacteria associated with coronal caries to initiate root surface caries, a rat model was used. root surfaces were exposed by gingivectomy in rats fed a caries-promoting diet and orally inoculated with either actinomyces viscosus m-100, streptococcus sobrinus (mutans) 6715, or both. a fourth group received a diet containing antibiotics. the animals were sacrificed 64 days following the gingivectomy performed on the right molar quadrants. gingivectomy significantly increase ...19892600749
comparative cariogenicity and dental plaque-forming ability in gnotobiotic rats of four species of mutans streptococci.the four species, each represented by two strains, all produced high levels of fissure caries in the upper and lower jaws of gnotobiotic fisher rats. streptococcus rattus strains and streptococcus mutans nctc 10832 gave low levels of approximal caries, whereas streptococcus cricetus, streptococcus sobrinus and strep. mutans nctc 10449 gave high levels. the only strains to produce buccal surface lesions were strep. sobrinus and strep. cricetus. all strains were able to form dense plaque in the ce ...19892610617
diversity of surface protein antigen a gene in the chromosomal dna of streptococcus sobrinus.a recombinant plasmid, pya724, containing an 8.45-kb dna fragment encoding surface protein antigen a (spaa) from streptococcus sobrinus 6715 was used to examine the dna homology of the spaa gene with chromosomal dna of streptococcus sobrinus b13n. restriction endonuclease bamhi-digested pya724 dna was 32p radio-labeled by nick-translation, and a southern blot dna-dna hybridization experiment was carried out. pya724 dna hybridized with a bamhi fragment of b13n chromosomal dna, and the size of thi ...19892626165
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 indiv ...19892632612
uptake of 14c-xylitol by xylitol-cultured streptococcus sobrinus atcc 27352 and streptococcus mitis atcc 36249 in vitro.the effect of three successive cultures in the presence of 6% xylitol on the uptake of 14c-xylitol was studied using resting cells of streptococcus sobrinus atcc 27352 and streptococcus mitis atcc 36249. in the case of s. mitis, the three successive cultures did not alter the growth inhibition observed in the presence of xylitol. in the case of s. sobrinus, however, growth inhibition decreased. the 14c-xylitol uptake experiments also demonstrated that uptake of xylitol by s. sobrinus was decreas ...19892633204
characterisation of monoclonal antibodies to common protein epitopes on the cell surface of streptococcus mutans and streptococcus sobrinus.three monoclonal antibodies (mab) were prepared against a cell surface antigen which cross-react between streptococcus mutans (serotypes c, e and f) and streptococcus sobrinus (serotypes d and g). two of the mab also recognise a determinant on the surface of streptococcus cricetus (serotype a). the common antigen shared between s. mutans and s. sobrinus was demonstrated by western blotting to be about 200 kd in size. this antigen is shared not only by the cell surfaces of serotypes a, c, d, e, f ...19892639299
salivary levels of putative cariogenic organisms in patients with eating disorders.the present study examined the hypothesis that women with eating disorders associated with a history of chronic vomiting can be characterized by a salivary flora with high levels of aciduric organisms, such as, mutans streptococci, lactobacilli and yeast. three groups of female subjects were studied: vomiting bulimics (g1; n = 14), and comparison groups selected for high streptococcus mutans (g2; n = 13), and low s. mutans levels (g3; n = 12). the prevalence and levels of mutans streptococci, la ...19892640318
homology between surface protein antigen genes of streptococcus sobrinus and streptococcus mutans.the structural gene (pag gene) for a 210 kda protein antigen of streptococcus sobrinus serotype g was cloned and compared with that (pac gene) of a 190 kda protein antigen of streptococcus mutans serotype c. immunodiffusion analysis revealed that the product of the pag gene immunologically cross-reacted with that of the pac gene. southern blot and nucleotide sequence analyses revealed that a significant homology existed between the middle regions of the two structural genes.19892661267
effect of desalivation and age on susceptibility to infection by streptococcus sobrinus.the influence of desalivation and age on susceptibility to infection by streptococcus sobrinus was studied using 80 sprague-dawley female rats weaned at age 21 days. forty animals (donors) were infected with s. sobrinus 6715 (atcc 27352), formed into ten groups of 4, fed diet 2000, and offered 10% sucrose water ad libitum. the remaining 40 animals were fed laboratory chow and sterile distilled water until introduced into the experiment. when the animals were aged 25 days, 10 noninfected animals ...19892743376
molecular characterization of a surface protein antigen gene from serotype c streptococcus mutans, implicated in dental caries.the complete nucleotide sequence of the gene for a cell-surface protein antigen (pac) of streptococcus mutans mt8148 (serotype c) was determined. the pac gene consisted of 4695 bp and coded for a 170773d protein. the pac gene product contained a putative 38 amino acid signal peptide, resulting in a 166817d mature protein. a potential promoter sequence and a putative shine-dalgarno sequence preceded the open reading frame. two internal repeating amino acid sequences were present in the pac. one r ...19892761390
effect of a bacteriocin-producing strain of streptococcus sobrinus on infection and establishment of streptococcus mutans on tooth surfaces in rats.the effect of bacteriocin produced by streptococcus sobrinus mt6223 on infection and establishment of streptococcus mutans mt6222 was studied in specific pathogen-free rats. these strains were isolated from a carious lesion of a single subject. s. mutans mt6222 was found to be susceptible to the growth inhibitory action of s. sobrinus mt6223. when simultaneously inoculated into the oral cavity of rats, even a small inoculum (10(5) cfu) of s. sobrinus mt6223 completely inhibited colonization of s ...19892762016
ultrastructural changes in streptococcus sobrinus induced by xylitol, naf and zncl2.the effect of xylitol, naf, or zncl2 on the ultrastructure of streptococcus sobrinus omz 176 was studied. the bacteria were grown statically in air for 8 h in brain-heart infusion broth supplemented with 33 mm xylitol, 2.5 mm naf, 0.5 mm zncl2, separately or in combination. the bacteria were washed briefly and prepared for scanning and transmission electron microscopy. all three agents and their combinations induced distinct ultrastructural alterations. the alterations were related to various as ...19892766317
prevention of rat fissure caries by sodium fluoride varnish (duraphat) with different fluoride concentrations.125 osborne-mendel rats were weaned at 22-23 days, inoculated with streptococcus sobrinus and fed a cariogenic diet for 40 days. the control group received no treatment; the study groups received applications of duraphat containing 2.3, 1.1, or 0.6% fluoride or a placebo varnish on days 21-23. the placebo varnish had no effect on caries. fissure caries was significantly reduced by the 2.3 and 1.1% fluoride varnishes, whereas the caries reduction found after treatment with the 0.6% fluoride varni ...19892766323
plaque inhibition by a combination of zinc citrate and sodium lauryl sulfate.bacteriological tests demonstrated an additive inhibitory effect of zncl2 and sodium lauryl sulfate (sls) on in vitro growth of streptococcus sobrinus omz 176 and of streptococcus sanguis atcc 10556. as measured by atomic absorption spectrophotometry, the solubility of zinc citrate increased in the presence of sls. after 48 h, the concentration of solubilized zinc from aqueous solutions of 5.0 mm zinc citrate was 12.0 mm versus 14.4 mm in the presence of 34.7 mm sls. the plaque-inhibiting proper ...19892790864
acidogenesis by oral streptococci at different ph values.streptococcus mutans is known to be one of the most cariogenic oral microorganisms. recently, organisms classified as s. mutans have been shown to be genotypically heterogeneous and to form at least six separate species. in this study, differences in acid production between the mutans streptococci and streptococcus sanguis were investigated at ph values from 5.0 to 7.0. while all of the species investigated were able to produce acids, streptococcus sobrinus was found to be significantly more aci ...19892920379
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 thioglyc ...19892920385
characterization of monoclonal antibodies against glucosyltransferase synthesizing water-insoluble glucan from streptococcus sobrinus b13.four hybrid cell lines secreting monoclonal antibodies (mcabs) against glucosyltransferase synthesizing water-insoluble glucan (gtase-i) were generated by fusion of myeloma cells (p3u1) with splenocytes from mice immunized with gtase-i from streptococcus sobrinus b13-n. cell lines 29e7, 21gc7, and 42hb8 were found to secrete an igg2a-type immunoglobulin, and 29eg, an igm-type immunoglobulin. these two isotypes of mcabs were used for the determination of the binding sites on the gtase molecule, w ...19901689748
characterization of cross-reactive polysaccharide antigen with serotype a and d strains from streptococcus sobrinus 6715.the polysaccharide antigen (designated si) from streptococcus sobrinus 6715 (serotype g) which cross-reacts with serotype a and d strains was purified by a specific anti-cross-reactive g-a antibody-sepharose 4b affinity column. by a double immunodiffusion analysis, the si antigen was found to lack the serotype-specific g site, but contained the cross-reactive sites g-a, g-d and g-(a-d) on a single molecule. polysaccharide si was composed of galactose, glucose and rhamnose in a molar ratio of 4.7 ...19901690575
regions of the streptococcus sobrinus spaa gene encoding major determinants of antigen i.surface protein antigen a (spaa), also called antigen b, antigen i/ii, or antigen p1, is an abundant cell envelope protein that is the major antigenic determinant of streptococcus sobrinus and other members of the streptococcus mutans group of cariogenic bacteria. this laboratory has previously reported the cloning and expression in escherichia coli of a bamhi restriction fragment of s. sobrinus dna containing most of the spaa gene (pya726) and encoding antigen i. regions of spaa encoding immuno ...19901694526
cross-reactivity between the immunodominant determinant of the antigen i component of streptococcus sobrinus spaa protein and surface antigens from other members of the streptococcus mutans group.most members of the streptococcus mutans group of microorganisms specify a major cell surface-associated protein, spaa, that is defined by its antigenic properties. the region of the spaa gene from streptococcus sobrinus 6715 encoding the immunodominant determinant of the major antigenic component (antigen i) of the spaa protein has recently been characterized. this study examined whether recognition of the immunodominant determinant is independent of the immunized animal host and whether antibo ...19901694822
construction of noti restriction map of the streptococcus mutans genome.streptococcus mutans and streptococcus sobrinus are the major causative organisms of human dental caries. pulsed-field gel electrophoresis (pfg) showed that the restriction enzyme noti produced ten and six dna fragments from the genomes of s. mutans strain mt8148 and s. sobrinus strain 6715, respectively. the sizes of the chromosomes of s. mutans and s. sobrinus were each estimated to be about 2200 kb. the noti restriction map of s. mutans mt8148 genome was constructed by southern blot analysis ...19902079621
binding of streptococci of the "mutans" group to type 1 collagen associated with apatitic surfaces.the present study surveyed the ability of 21 strains of cariogenic streptococci of the "mutans" group to bind to human type 1 collagen adsorbed on hydroxyapatite (ha) surfaces. all strains of streptococcus cricetus (serotype a) and streptococcus rattus (serotype b) tested attached strongly to collagen-treated ha (c-ha). streptococcus mutans strains of serotype c and streptococcus sobrinus strains of serotype d or g attached poorly; or not at all, to c-ha. s. mutans strains omz-175 (serotype f) a ...19902080067
human strains of mutans streptococci show different cariogenic potential in the hamster model.the cariogenic potential of fresh humans strains of streptococcus mutans and streptococcus sobrinus was examined in hamsters maintained on a high sucrose diet. the strains 1b 16 (s. mutans) and b13 (s. sobrinus) isolated 20-25 yrs ago served as positive controls. three series of experiments were run. some strains were tested once and some strains were tested in all 3 experiments. the animals infected with s. sobrinus strains generally showed lower caries scores than those infected with s. mutans ...19902082240
cloning of the amino terminal nucleotides of the antigen i/ii of streptococcus sobrinus and the immune responses to the corresponding synthetic peptides.a portion of the antigen i/ii (spaa, b, p1) gene of streptococcus sobrinus 6715, containing the coding sequence for the amino terminal 684 amino acids of the protein, was cloned in bacteriophage lambda gt10. selection was by immunological detection using a polyclonal antiserum to the antigen i/ii from strep. mutans. from the amino acid sequence, peptides were synthesized, 15 amino acids in length, that covered the entire sequence. in total, 260 synthetic peptides were synthesized and evaluated f ...19902088235
maintenance of proton motive force by streptococcus mutans and streptococcus sobrinus during growth in continuous culture.the components of the transmembrane electrochemical proton gradient, or proton motive force (pmf, delta p), were determined in cells of streptococcus mutans ingbritt and streptococcus sobrinus atcc 27352 growing in continuous culture under conditions of changing glucose concentration, growth rate and growth ph. the ph gradient (delta ph) and membrane electrical potential (delta psi) were assayed with the weak acid, salicyclic acid, and the lipophilic cation, methyltriphenylphosphonium iodide, re ...19902098703
a iiiman protein is involved in the transport of glucose, mannose and fructose by oral streptococci.we show in this article that the transport of glucose, mannose and fructose by the phosphoenolpyruvate: mannose phosphotransferase system of oral streptococci requires the participation of a protein component that we have called iiiman. this protein was purified from streptococcus salivarius by chromatography on deae-cellulose, deae-tsk, hydroxyapatite, and dyematrex green a. the purified protein migrated as a 38,900 molecular weight protein on a sodium dodecyl sulfate polyacrylamide gel. howeve ...19902098704
dental caries in congenitally athymic rats.the importance of the immune response in dental infection was evaluated in heterozygous (rnu/+) normal and homozygous (rnu/rnu) congenitally athymic "nude" rowett rats. animals of both types were infected, or immunized and infected, with mutans streptococci (streptococcus sobrinus strain 6715). the mean numbers of s. sobrinus cells recovered from the nude rats were higher than those from comparable (immune/nonimmune) normal rats in 10 of 12 possible comparisons. also, s. sobrinus constituted a g ...19902098708
influence of sweetening agents in solution on dental caries in desalivated rats.sucralose (trichlorogalactosucrose), sorbitol and aspartame in drinking water induced little or no caries in desalivated rats infected with streptococcus sobrinus and actinomyces viscosus and receiving their essential nutrition by gastric gavage. in contrast, sucrose and fructose induced extensive decay. only sucrose could sustain implantation of strep. sobrinus in these animals. the populations of a. viscosus were sparse (0.3-0.5%) in the animals given fructose and sucrose. large populations of ...19902124801
[inhibitory effects of a hot water extract from japanese tea on the cell growth of mutans streptococci].this study was undertaken to examine the effect of a hot water extract from japanese tea on the cellular growth of mutans streptococci in vitro. the extract contained polyphenol compounds, mainly catechin derivatives. few fluoride components were contained in the extract. streptococcus mutans mt8148r (serotype c) and s. sobrinus mt6715 (serotype g) strains were used in the present study. the organisms (10-10(7) cfu/ml) were cultured in brain heart infusion (bhi) and tryptose phosphate (tp) broth ...19902133962
[detection of mutans streptococci by latex agglutination test and its application as a caries-activity test].the number of mutans streptococci in saliva and dental plaque has been reported to correlate with the incidence of dental caries. this report describes a simple and rapid diagnostic method for the detection of mutans streptococci in dental plaque using latex agglutination (la) test. latex particles (0.876 microns, diameter) were sensitized with partially purified antibodies against whole cells of streptococcus mutans mt8148 (c), mt703r (e) and omz175 (f) and streptococcus sobrinus b13 (d) and 67 ...19902135419
characterization of glucan involved in the reduction of dental caries in rats.culture supernatant fluids (sf) of mutant 108 obtained from streptococcus sobrinus 6715, when incubated with sucrose, produce large amounts of water-soluble glucans. mainly, two water-soluble glucan synthesizing glucosyltransferases (gtases) were found in culture sf by isoelectric focusing. these two gtases had higher activities than those from the parent strain. the gtase which synthesizes water-insoluble glucan totally lacked the mutant. when the glucan preparation synthesized by the sf was su ...19902137352
size and subdomain architecture of the glucan-binding domain of sucrose:3-alpha-d-glucosyltransferase from streptococcus sobrinus.mild trypsin proteolysis of streptococcus sobrinus sucrose:3-alpha-d-glucosyltransferase (gtf-i) reduced most of the enzyme to small products but left a few large fragments undigested. the digest had no glucosyl transfer activity, but several digestion products had an affinity for glucan equivalent to that of the native enzyme. the glucan-binding fragments ranged in size from 17 to 60 kilodaltons (kda), with a particularly prominent 42-kda fragment. the largest of these (60 kda) appears to be th ...19902142138
analysis of the streptococcus downei gtfs gene, which specifies a glucosyltransferase that synthesizes soluble glucans.the complete nucleotide sequence was determined for the streptococcus downei (previously streptococcus sobrinus) mfe28 gtfs gene which specifies a glucosyltransferase (gtf-s) producing water-soluble glucan. a single open reading frame which encodes a mature protein with a molecular weight of 147,408 (1,328 amino acids) and a putative signal peptide 36 or 37 amino acids in length was detected. gtf-s shares extensive sequence similarity with gtf-i (gtfi) from s. downei and gtf-i (gtfb) and gtf-si ...19902142479
the influence of sucralose on bacterial metabolism.sucralose (1',4',6' trideoxy-trichloro-galactosucrose) is a nontoxic, intensely sweet sucrose derivative that has been shown to be non-cariogenic in experimental animals. the purpose of this study was to determine whether certain oral bacteria could utilize sucralose. sucralose, as a sole carbon source, was unable to support growth of ten strains of oral bacteria and dental plaque. when sucrolose was incorporated into a liquid medium containing glucose or sucrose, all organisms tested displayed ...19902143512
characterization of the product of the gtfs gene of streptococcus downei, a primer-independent enzyme synthesizing oligo-isomaltosaccharides.the gtfs gene, coding for a glucosyltransferase which synthesizes water-soluble glucan and previously cloned from streptococcus downei strain mfe28 (mutans serotype h) into a bacteriophage vector, was subcloned into a plasmid vector. the gtfs gene products expressed in escherichia coli were compared to the primer-independent, oligo-isomaltosaccharide synthase in streptococcus sobrinus strain aht (mutans serotype g) and shown to resemble it closely in molecular mass, isoelectric point, immunologi ...19902148181
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