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At least 19 recordsLinked to original sources
PubMed1978

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

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

Agglutination↗
PubMed1979

Serotype-dependent inhibition of glucan synthesis and cell adherence of Streptococcus mutans by antibody against glucosyltransferase of serotype e S. mutans.

A crude glucosyltransferase (GTase) preparation was obtained from the culture supernatant of Streptococcus mutans strain MT703 (serotype e) by 50% ammonium sulphate precipitation. Antiserum specific against the GTase was prepared by immunizing rabbits intramuscularly with the GTase in Freund incomplete adjuvant, followed by GTase without adjuvant intravenously. Gamma globulin fractions of the antiserum and normal serum were partially purified by 1/3 saturated ammonium sulphate precipitation. The antibody strongly inhibited the GTase activity (greater than 90%) of type c, e and f S. mutans, whereas the GTase of type a, d and g was not affected by the antibody. The GTase from type b S. mutans was slightly inhibited. The adherence of viable cells of type c, e, and f S. mutans to a glass surface due to synthesis of glucan by the cell-associated GTase was also significantly inhibited by the antibody to the enzyme. These results suggest that type c, e, and f and types a, d, and g S. mutans can be separated into two major groups in terms of the immunological relationship of GTase.

Antibodies, Bacterial↗
PubMed1976

Adherence of serotype e Streptococcus mutans and the inhibitory effect of Lancefield group E and S mutans type e antiserum.

S mutans strain MT703 from an active carious lesion in the tooth of a child had type e specificity and showed a cross-reaction with the Lancefield group E cell wall streptococcal polysaccharide antigen. Heat-killed cells MT703 adhered to a glass surface in the presence of CGT MT703 and sucrose. Pretreatment of the cells with anti-MT703 whole cell serums inhibited adherecne. The removal of glycerol teichoic acid antibody and group E antibody from the MT703 serum did not result in a loss of inhibitory activity. Antiserum with or without adsorption significantly inhibited glucan synthesis by CGT from sucrose. Antibodies specific for the polyglycerol phosphate of teichoic acid did not inhibit adherence. Anti-group E serum and serums specific for other types of S mutans, did not show adherence inhibitory activity except for an occasional type c specific antiserum. Antibody specific for the type e antigen produced significant inhibition of the binding of CGT to the MT703 cell wall, and adherence of these cells did not occur. Antibody to CGT inhibited glucan synthesis. Treatment of the cells with dextranase, dextran antibody, or trypsin caused a significant reduction in adherence. The results suggest that the type antigen and dextran on the surface of the S mutans type e cell are functional in adherence, and that these polymers are associated with cell wall protein.

Glucose↗
PubMed2025

SloR-SRE binding to the S. mutans mntH promoter is cooperative.

UNLABELLED: Streptococcus mutans is a commensal member of the plaque microbiome. It is especially prevalent when dietary sugars are available for S. mutans fermentation, generating acid byproducts that lower plaque pH and foster tooth decay. S. mutans can survive in the transient conditions of the mouth, in part because it can regulate the uptake of manganese and iron during periods of feast when metal ions are available, and famine when they are limited. S. mutans depends on a 25kDa metalloregulatory protein, called SloR, to modulate the uptake of these cations across the bacterial cell surface. When bound to manganese, SloR binds to palindromic recognition elements in the promoter of the sloABC genes that encode the major manganese transporter in S. mutans. Reports in the literature describe MntH, an ancillary manganese transporter in S. mutans, that is also subject to SloR control. In the present study, we performed expression profiling experiments that reveal coordinate regulation of the sloABC and mntH genes at the level of transcription. In addition, we describe a role for the mntH gene product that is redundant with that of the sloABC-encoded metal ion uptake machinery. The results of DNA-binding studies support direct SloR binding to the mntH promoter region which, like that at the sloABC promoter, harbors three palindromic recognition elements to which SloR binds cooperatively to repress downstream transcription. These findings expand our understanding of the SloR metalloregulome and elucidate SloR-DNA binding that is essential for S. mutans metal ion homeostasis and fitness in the oral cavity. IMPORTANCE: Dental caries disproportionately impacts low-income socioeconomic groups in the United States and abroad. Research that is focused on S. mutans, the primary causative agent of dental caries in humans, is significant to mitigation efforts aimed at alleviating or preventing dental caries. The SloR protein is a major regulator of the S. mutans metal ion uptake machinery encoded by the sloABC- and mntH genes. This SloR-mediated gene control is essential for maintaining intracellular metal ion homeostasis, and hence S. mutans fitness in the plaque microbiome. An improved understanding of the sloABC and mntH metal ion transporters and their regulation by SloR can guide rational drug design that, by targeting the SloR-DNA-binding interface, can alleviate or prevent S. mutans-induced disease.

Streptococcus mutans↗
PubMed1977

A sequential bacteriological and serological investigation of Rhesus monkeys immunised against dental caries with Streptococcus mutans.

In a serial investigation of the effects of immunisation with S. mutans in rhesus monkeys maintained on a "human" type of cariogenic diet, the numbers of S. mutans in cervical plaque, crevicular-fluid washings, fissures of teeth, and in saliva were lower in immunised animals than in sham-immunised controls. Immunisation also caused a delay in initial colonisation and a slowing of the rate of colonisation with S. mutans. These bacteriological changes were associated with a reduction in the smooth-surface-caries score. No relationship was found between the presence of S. sanguis and caries, but there was an inverse relationship between the proportions of S. mutans and S. sanguis isolated. Increased titres of complement-fixing, haemagglutinating and precipitating antibodies to S. mutans were found in the sera of immunised but not of control monkeys. A significant increase in salivary haemagglutinating antibodies was not detected. The results suggest that immunisation with S. mutans causes an increase in serum antibodies and a reduction in the number of S. mutans in the oral flora, and that these are associated with a reduction in dental caries.

Animals↗
PubMed1979

Effect of chlorhexidine on the relative proportions of Streptococcus mutans and Streptococcus sanguis in hamster plaque.

The effect of chlorhexidine on the proportions of Streptococcus mutans and Streptococcus sanguis in plaque was studied in hamsters fed a diet containing 28% sucrose. In animals given chlorhexidine in their drinking water for 10 d a decrease in the population of S. mutans and an increase of S. sanguis occurred in the plaque. Following the removal of chlorhexidine the population of S. mutans increased again in the presence of sucrose and the number of S. sanguis returned to initial values. When animals were given a sucrose-free diet the low proportion of S. mutans observed following the short-term chlorhexidine period persisted. These data indicate that there is an inverse relationship between the number of S. sanguis and S. mutans in plaque and that the sensitivity in vivo of S. mutans to chlorheximide can be used to suppress the population of S. mutans with a concomitant rise in the proportion of S. sanguis.

Animals↗
PubMed1978

Binding of glucosyltransferase and glucan synthesis by Streptococcus mutans and other bacteria.

Lyophilized and heat-treated cells from the seven serotypes of Streptococcus mutans were examined for their ability to bind added insoluble-product glucosyl-transferase (GTase) and to synthesize cell-associated glucan from [(14)C]sucrose. Lyophilized cells of serotypes a and g did not synthesize any more additional glucan than did the controls after exposure to GTase. These cells, however, synthesized four- to eightfold-greater quantities of glucan than did the cells of the remaining serotypes. Lyophilized cells of serotypes b, c, d, e, and f synthesized two- to threefold-greater quantities of glucan after exposure to GTase than did the controls without added enzyme. Lyophilized cells of serotypes a and g synthesized 6- to 10-fold-greater quantities of glucan than did heat-treated cells of the same strain after binding of GTase. Lyophilized cells of the remaining serotypes synthesized only 1.6- to 3.3-fold-greater quantities of glucan than did the heat-treated cells. These results demonstrate that heat treatment to inactivate cell-associated GTase does not create additional GTase binding sites in S. mutans and that serotypes a and g are considerably more active in cell-associated glucan synthesis than cells of the other five serotypes. Ten species of gram-positive and gram-negative bacteria from five genera which do not produce in vitro plaque synthesized 10- to 100-fold-less glucan than did the S. mutans strains after exposure to GTase. Of these species, S. sanguis, Actinomyces viscosus, and A. naeslundii synthesized the largest quantities of glucan. Three mutant strains of S. mutans which possess a reduced ability for in vitro adherence but do agglutinate with glucan or dextran synthesized only one-third as much glucan after binding of GTase as the control. These results are discussed in relation to in vitro and in vivo plaque development and the agglutination of S. mutans. The results support earlier findings which indicate that the presence of bacterial species other than S. mutans in smooth-surface dental plaque is due in part to contact of the cells with glucan in the developing plaque and not to the binding of cell-free GTase and the in situ synthesis of glucan. The results obtained with these representative strains of the seven serotypes of S. mutans may not apply to the same extent to other strains within the serotypes.

Escherichia coli↗
PubMed1979

Longitudinal investigation of the role of Streptococcus mutans in human fissure decay.

A prospective study was initiated in order to detect changes in the levels and proportions of Streptococcus mutans, S. sanguis, and lactobacilli before and at the time of caries development on occlusal fissures. The bacteriological analysis was performed on 195 teeth that received four examinations at approximately 6-month intervals. The data obtained from 42 carious fissures and 153 caries-free fissures strongly indicated an etiological role for S. mutans in most of the diagnosed fissure lesions. This was demonstrated by the longitudinal analysis, which showed the proportions of S. mutans to increase significantly at the time of caries diagnosis, and by cross-sectional comparisons, which showed that the proportions of S. mutans in the carious fissures were significantly higher than in caries-free fissures. Three subjects who had a low caries expereince developed five new carious lesions. Lactobacilli were prominent members of the caries-associated flora in these subjects greatly outnumbering S. mutans. The levels and proportions of S. sanguis tended to be higher in the caries-free fissures. Altho1gh the results are striking in that they implicate S. mutans in fissure decay, they show that clinical decay can occur in a few instances in the absence of detectable S. mutans, as was observed in the fissures high in lactobacilli.

Bacteriological Techniques↗
PubMed1979

Examination of parotid saliva for antibodies reacting with Streptococcus mutans, lipoteichoic acid and peptidoglycan by the enzyme-linked immunosorbent assay.

Human parotid saliva was investigated for the presence of IgA antibodies reacting with Streptococcus mutans, lipotechoic acid (LTA) and peptidoglycan. By using an enzyme-linked immunosorbent assay, ELISA, it was shown that the salivas of 12 subjects contained antibodies reacting with S. mutans serotype c and d and with LTA. Six salivas were tested against peptidoglycan but these tests indicated only low levels of antibodies. Absorption of saliva with whole cells of S. mutans inhibited the homologous reaction by up to 87% and the reaction with LTA by up to 52%. Also prior treatment of saliva with LTA caused a decrease in the salivary IgA reaction with LTA and with whole cells of S. mutans. Addition of peptidoglycan to saliva did not markedly affect the salivary IgA reaction with S. mutans. The data show that LTA may be responsible for part of the salivary IgA reaction with whole cells of S. mutans. The significance of LTA in this reaction may vary between different subjects and for different serotypes of S. mutans.

Adolescent↗
PubMed1977

Serological studies on strains of Theileria mutans isolated in East Africa using the indirect fluorescent antibody technique.

The serological response of cattle infected with Theileria mutans (Aitong) by cyclical and mechanical transmission was studied using the indirect fluorescent antibody technique with T. mutans piroplasm and schizont antigens. Cattle infected by either method show high antibody titres against piroplasm antigens which persist for periods of over one year. Only cattle with tick-induced infections had an antibody response to schizont antigen. The serological cross-reactions of T. mutans (Ationg) with other strains of T. mutans isolated in East and South Africa sere investigated as were the serological cross-reaction of T, mutans (Aitong) and other species of Theileria. It was concluded that isolated of Theileria in East Africa which behaved like T. mutans were serologically indistinguishable using the IFA technique while other species of Theileria were easily distinguishable from T. mutans.

Animals↗
PubMed1979

Stability of the resident microflora and the bacteriocinogeny of Streptococcus mutans as factors affecting its establishment in specific pathogen-free rats.

The outcome of the experimental implantation of Streptococcus mutans strains in humans and animals is unpredictable, and neither success nor failure can be explained. It seems logical to assume that, apart from dietary and host factors, the characteristics of the S. mutans strain involved and those of the resident plaque microflora are important in colonization. For example, previous work in this laboratory suggested that bacteriocin production accounts at least in part for the establishment of an invading bacterium in a microbial ecosystem. In the present study, a complex specific pathogen-free Ny plaque ecosystem was obtained by the inoculation of specific pathogen-free rats with Actinomyces viscosus Ny1 and S. sanguis Ny101, and the establishment of S. mutans in such rats was then examined. It was found that bacteriocinogenic (bac(+)) strains generally colonized in much higher proportions than non-bacteriocinogenic (bac(-)) strains. Moreover, the longer the delay in introducing S. mutans, the poorer was its establishment. Shortly after inoculation of strains Ny1 and Ny101, there is probably a transient state in which microbial equilibrium has not been reached, but later the specific pathogen-free Ny system attains a stable climax community which more strongly resists invaders. The ability of a number of S. mutans strains to establish in such a climax community was then examined, and it was found that bac(+) strains generally established at a higher level than did bac(-) strains. In summary, it was concluded that, although the bac(+) state is an important property in the successful invasion of a plaque by S. mutans, the stability of the resident microflora is also an important factor.

Actinomyces↗
PubMed2026

An XRE-type regulator in Streptococcus mutans plays an important role in brpA expression and oxidative stress tolerance response.

This study used a functional genomics approach to explore the role of a xenobiotic response element (XRE)-type regulator (SMU.405c) in Streptococcus mutans physiology, including the expression of biofilm regulatory protein BrpA. Results showed that deletional mutation of xre significantly reduced the ability of the deficient mutant to grow in the presence of methyl viologen, a commonly used oxidative stressor (P < 0.001). When challenged in a hydrogen peroxide killing assay, the survival rate of the &#x2206;xre mutant was >2-log less than the parent strain after 60 min (P < 0.001). Luciferase reporter fusion assays showed that xre deficiency had no significant effect on luciferase expression when it was under the control of the intact brpA promoter, but the reporter activity increased by >6-fold (P < 0.001) when the reporter gene was fused to a brpA promoter derivative with deletion of a putative XRE-binding box. Electrophoretic mobility shift assay (EMSA) showed that recombinant XRE interacted with the brpA promoter, resulting in an electrophoretic shift of the promoter probes. In vitro transcription assay also showed that inclusion of XRE caused transcription to fall off, significantly reducing full-length brpA transcripts. RNA-seq analysis revealed that deficiency of XRE led to altered expression of >102 genes by >2-fold (P < 0.05), including 28 with increased expression, and 74 with decreased expression. Among the down-regulated were genes for DNA repair and oxidative stress tolerance response. These results suggest that XRE (SMU.405c) in S. mutans plays an important role in brpA expression and oxidative stress tolerance response.IMPORTANCEStreptococcus mutans, a keystone pathogen in human dental caries, primarily lives in the highly diverse microbiota on tooth surfaces, where the conditions are often harsh and fluctuate frequently. Locus SMU.405c was annotated to encode a xenobiotic response element (XRE)-like transcriptional regulator, but no information is available concerning the role of this protein in S. mutans pathophysiology. This study used a functional genomics approach along with molecular and transcriptomic analysis to characterize a deletional xre mutant, and the results showed that xre deficiency in S. mutans resulted in weakened oxidative stress tolerance response and alterations in transcription of >102 genes, including those known to play an important role in cell envelope biogenesis and stress tolerance response. Reporter fusion assay, electrophoretic mobility shift assay (EMSA), and in vitro transcription further demonstrated that the XRE-like regulator encoded by SMU.405c is a repressor of brpA expression and plays an important role in oxidative stress tolerance response.

Streptococcus mutans↗
PubMed1979

Radioimmunoassay of class-specific antibodies to Streptococcus mutans in monkey serum and saliva.

A radioimmunoassay (RIA) has been developed to measure class-specific antibodies to Steptococcus mutans in the serum and saliva of monkeys (Macaca fascicularis). Anti-human immunoglobulin antibodies purified by affinity chromatography on immobilised monkey immunoglobulins and labelled with 125I were employed. Formolised cells of S. mutans and an extract of culture supernatant adsorbed to polystyrene wells were used as solid-phase antigens. The coefficients of variation for IgG, IgA and IgM assays were less than or equal to 10% for both antigen systems. Two monkeys were immunised with formolised cells of S. mutans by subcutaneous injection and subsequent instillation of bacterial cells into their right parotid ducts. IgG, IgA and IgM antibody responses to S. mutans in samples of serum and saliva were quantitated by RIA. Immobilisation of purified components of S. mutans on polystyrene wells enabled the measurement of antibody response to a number of antigens to be made. The RIA is a sensitive, reproducible and quantitative method of measuring serum and salivary antibody responses in monkeys.

Adsorption↗
PubMed1976

Chemical and immunological properties of the type f polysaccharide antigen of Streptococcus mutans.

The type-specific cell wall polysaccharide antigen was extracted, purified, and characterized from type f Streptococcus mutans strain OMZ175 and MT557. The antigen was extracted from lyophilized cells with 5% trichloroacetic acid at 85 C for 15 min or saline at 120 C for 30 min. The trichloroacetic acid antigen was chromatographically separated into three antigenic fractions on a diethylaminoethyl-Sephadex A-25 column. Antigen 1 (Ag1P), which was specific for type f antiserum, was further purified by passing through carboxymethyl-Sephadex C-25 and Sephadex G-200 columns. It was a polysaccharide composed of 49% rhamnose and 47% glucose. No reaction was obtained with anti-polyglycerophosphate (PGP) serum. Antigen 2 was reactive with both type f and PGP antisera and contained significant amounts of protein and phosphorus. Antigen 3 was reactive only with PGP antiserum and had no type specificity. The polysaccharide antigen gave a single precipitin band against type-specific antiserum on immunodiffusion and immunoelectrophoresis. The presence of alpha-1,6-glucosidic linkages was indicated by a 90% inhibition of the precipitin reaction by isomaltose and alpha-methyl-D-glucopyranoside, adsorption to and release from a concanavalin A-Sepharose column, and reaction with an S. mutans (type e) glucan antiserum. This antiserum was used to show that the type f polysaccharide antigen did not contain free glucan. An analysis of the antigen released from the antigen-glucan antiserum complex showed the presence of rhamnose and glucose. This released antigen also reacted with an f antiserum, which did not react with commercial dextran. The results show that the type f polysaccharide antigen is the first of those S. mutans type-specific polysaccharides identified to be immunologically related to an S. mutans glucan.

Antigens, Bacterial↗
PubMed1977

Binding of lectins to Streptococcus mutans cells and type-specific polysaccharides, and effect on adherence.

The lectin concanavalin A (Con A) agglutinated the cells of 13 of 15 strains of the seven serotypes of Streptococcus mutans in an 18-h incubation period. Strains of types a, d, f, and g agglutinated within 2 h. Strains of a, d, and f were also agglutinated in 2 h by the castor bean lectin RCA. S. sanguis, S. salivarius, S. bovis, Actinomyces viscosus, A. naeslundii, and Lactobacillus plantarum were agglutinated within 2 h. The S. mutans type f polysaccharide was precipitated by Con A. The a, b, c, d, and e polysaccharides were not precipitated. Glucan from d and e strains of S. mutans and dextran T2000 were also precipitated by Con A. D-glucose inhibited the agglutination of type f cells by Con A and the agglutination of type d cells by D-galactose. The quantity of [acetyl-3H]Con A bound was not proportional to the degree of agglutination. Cells grown in sucrose medium bound more Con A than those grown in glucose medium. After treatment with dextranase, the sucrose-grown cells bound two- to fourfold more Con A. The binding of Con A to the type-specific polysaccharide or to teichoic acid could not be determined by the use of specific antibody due to the binding of Con A to the antibody globulin on the cell surface. Con A bound to S. mutans cells did not inhibit the activity of cell-bound glucosyltransferase, glucan synthesis, and in vitro adherence. Bound Con A also did not inhibit the ability of heat-treated cells to bind glucosyltransferase, synthesize glucan, and produce in vitro adherence.

Agglutination↗
PubMed1978

Selective binding of blood group-reactive salivary mucins by Streptococcus mutans and other oral organisms.

Strains of Streptococcus mutans of four genetic groups and five serotypes, and strains of S. sanguis, S. mitis, S. salivarius, Actinomyces naeslundii, and A. viscosus, were found to bind blood group-reactive (BGR) mucin isolated from whole human saliva. The bacteria studied bound mucins with blood type A or B reactivity to a similar extent, suggesting that the carbohydrate moieties responsible for the A and B antigenic determinants were not involved. The organisms studied appeared to bind different fractions of BGR mucin molecules because preparations absorbed with cells of a given oral species no longer contained BGR molecules which bound to homologous organisms but still possessed BGR components which bound to varying degrees to other bacteria. Differences were even noted among S. mutans strains belonging to different genetic groups and serological types. Immunoglobulins could not be detected in the mucin preparations, and addition of anti-human immunoglobulin A (IgA), IgG, or IgM serum to reaction mixtures did not affect binding. Mucin pretreated with periodate or iodoacetate no longer bound to S. mutans H12 cells, suggesting that carbohydrate moieties and sulfhydryl groups played an essential role. Active cell metabolism was not required for BGR mucin binding; however, pretreatment of H12 cells with periodate or heat (100 degrees C for 15 min) reduced binding. Mucin labeled with [(14)C]phenyl isothiocyanate appeared to bind to S. mutans H12 cells comparably to untreated mucin; the binding also appeared to be specific because less than 15% of the labeled material became bound when incubated with an excess of streptococci. Binding of [(14)C]phenyl isothiocyanate-labeled mucin was not affected by neutral sugars tested or by preparations of c antigen, glycerol teichoic acid, dextran, or crude glucosyltransferase. However, binding was inhibited by several amines. BGR salivary mucins are present in the acquired pellicle covering teeth; the ability of bacteria to selectively bind such components suggest that they may serve as receptor molecules involved in the attachment of bacteria to teeth.

Actinomyces↗