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PubMed1985

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-linked rhamnose units. Side chains appeared to be composed of 1,2- and 1,6-linked glucose units with glucose as the only terminal carbohydrate.

Antigens, Bacterial↗
PubMed1996

Effect of antibodies on chemiluminescence and on killing of Streptococcus sobrinus by polymorphonuclear leukocytes.

The effect of a polyclonal antiserum and OMVU10, a monoclonal antibody reactive with Antigen B of Streptococcus sobrinus, on the interaction of polymorphonuclear leukocytes with S. sobrinus was studied, using chemiluminescence and bacterial killing assays. Increased stimulation of neutrophils as measured in the chemiluminescence assays was established when S. sobrinus was preincubated with polyclonal antiserum or when polyclonal antiserum was added to the reaction mixture. Higher counts were measured in comparison to preimmune serum. After 90 min, 52% of S. sobrinus preincubated with polyclonal antiserum was killed. Killing was also increased when polyclonal antiserum was added to the reaction mixture in comparison to the controls. No killing was found when bacteria were preincubated with OMVU10 or when OMVU10 was added to the reaction mixture in comparison to Clone 24, a control antibody.

Antibodies, Bacterial↗
PubMed2000

Polycarboxylates inhibit the glucan-binding lectin of Streptococcus sobrinus.

Polycarboxylates, such as carboxymethylcellulose and hyaluronan, were found to be reversible inhibitors of the glucan-binding lectin of Streptococcus sobrinus. When the carboxylate groups were coupled to ethylenediamine, or reduced with carbodiimide-borohydride, inhibitory powers were lost. Similarly, N-deacetylated hyaluronan had poor inhibitory powers, probably due to the introduction of positive charges into the polymer. Other polymers, such as chondroitin sulfates, dextran sulfate, fetuin, heparin were not inhibitors. It appears that inhibition is based on repeating carboxylates, free of influence from ammonium groups. Such polymers have the property of complexing with metals. Earlier studies had concluded that the streptococcal lectin depended on manganese for activity. It is likely the carboxymethylcellulose and hyaluronan perturb essential metal coordination centers in the lectin. Polycarboxylates may have value in oral health care by acting on glucan-dependent microbial adhesion and biofilm formation.

Bacterial Proteins↗
PubMed2001

Antibacterial effect of parabens against planktonic and biofilm Streptococcus sobrinus.

Tooth decay is an infectious disease caused by bacteria immobilized on the tooth surfaces. Eradication of these bacteria, for example Streptococcus sobrinus (S. sobrinus), from the oral cavity is essential in the prevention and treatment of tooth decay. We have tested the antimicrobial effect of several paraben derivatives such as methyl (MP), ethyl (EP), propyl (PP) and butyl (BP) against immobilized and planktonic S. sobrinus. The antibacterial effect was as follows: MP>EP>PP=BP on immobilized bacteria and MP>EP=PP>BP on planktonic bacteria. An antibacterial synergistic effect was found between several combinations of parabens on immobilized and planktonic S. sobrinus. Our results indicate that parabens are potential antibacterial agents against immobilized or planktonic bacteria found in the oral cavity.

Anti-Bacterial Agents↗
PubMed2004

Longitudinal study of transmission, diversity, and stability of Streptococcus mutans and Streptococcus sobrinus genotypes in Brazilian nursery children.

The aim of this study was to perform a follow-up evaluation of the Streptococcus mutans and Streptococcus sobrinus colonization profile of children's oral cavities, which included the pattern of vertical transmission from mother to child, genotypic diversity, and stability of the strains. The subjects were 16 mother-child pairs, who were monitored for 20 months. Samples of saliva, tongue dorsum, alveolar ridge mucosa, and dental plaque from the children were collected bimonthly. Saliva samples from the mothers were also collected. After isolation and identification, the arbitrarily primed PCR method was performed for the genotypic characterization of S. mutans (968 isolates) and S. sobrinus (111 isolates). At the time the strains were acquired, the children harbored one to four distinct genotypes of S. mutans and only one genotype of S. sobrinus. Although S. mutans prevalence and genotypic diversity were greater than those of S. sobrinus, the presence of matching genotypes of S. mutans and S. sobrinus was similar (in 81.25 and 83.33% of mother-child pairs, respectively), suggesting vertical transmission for both species. This longitudinal study showed an increase in genotypic diversity of S. mutans in the oral cavity during the follow-up period: most of the initially acquired genotypes persisted, normally those genotypes transmitted by the mother, and some were lost during follow-up; new strains were also acquired. In conclusion, S. mutans and S. sobrinus genotypes acquired from maternal or alternative sources may show effective persistence in the oral cavity and/or transitory detection in the children's mouths, reflecting the continuous development of oral microbiota in children.

Adult↗
PubMed1997

Adsorption of Streptococcus sobrinus dextranase inhibitor to water-insoluble alpha-D-glucans of oral streptococci.

A low molecular weight dextranase inhibitor from Streptococcus sobrinus has previously been identified and purified. The range of conditions under which inhibition occurs, and the situations in which dextranase activity of S. sobrinus can reappear, have been examined in the chemostat. These studies have revealed that when dextranase production exceeds that of the inhibitor, all the inhibitor is tightly bound into enzyme-inhibitor complexes, and the excess enzyme remains active. Another factor that influences the activity of dextranase inhibitor has now been identified, namely the ability of the inhibitor to bind to water-insoluble glucans. Adsorption to water-insoluble alpha-D-glucans, produced by oral streptococci that were grown in batch culture, increased with their proportion of alpha-1,3-linked sequences of glucose residues. Studies with water-insoluble dextrans of Leuconostoc mesenteroides strains showed that alpha-1,6-linked sequences were also important for binding. The inhibitor was not active when adsorbed to glucan, but active inhibitor was released by incubation with soluble dextran. The interactions of sucrose, alpha-D-glucosyltransferases, alpha-D-glucans, dextranase and dextranase inhibitor are discussed in relation to the growth rate of S. sobrinus. At low growth rate in the chemostat the predominant alpha-D-glucosyltransferase (GTF) is a GTF-S that converts sucrose into soluble dextran, and the activity of free dextranase inhibitor in the culture filtrate is high. By contrast, at high growth rate the streptococci produce GTFs capable of synthesizing water-insoluble alpha-D-glucans, and no free inhibitor is found in culture filtrate. Thus the activity of free, extracellular dextranase inhibitor is controlled by (i) the extent of binding to dextranase and (ii) the extent of adsorption to water-insoluble alpha-D-glucan.

Adsorption↗
PubMed2006

Streptococcus sobrinus in children and its influence on caries activity.

AIM: This was to study the longitudinal assessment of caries activity of Streptococcus sobrinus (SS) positive children during their mixed dentition. METHODS: The occurrence of mutans streptococci (MS) in plaque and saliva was determined in a representative sample of 55 children aged 8 to 12 years over a period of 4 years. A total of 708 bacterial strains was isolated which were identified as MS or SS. Caries activity (DeltaD(1-4)MFS) as well as plaque and gingival inflammation were recorded. RESULTS: During the period of observation 52 of the 55 children harboured MS; 12 of these children were SS positive. SS was not permanently detectable and 3 of the children were MS and SS negative. SS was not found without the presence of MS. Children that were infected with both SS and MS showed a slightly higher increase in caries compared with children that were infected exclusively by MS (DeltaD(1,2)MFS 6.2 vs. 3.0 and DeltaD(3,4)MFS 5.3 vs. 3.8) over the period of 4 years. An SS infection accelerated the increase of DeltaD(3,4)MFS significantly by a factor of 4 one year after its detection, whereas the DeltaD(1,2)MFS was 3 times as high during the period of infection. CONCLUSION: The findings suggest that an SS infection represents an important additional risk factor for dental caries due to its obvious aggravating of caries activity.

Child↗
PubMed1991

Sequence and structural analysis of surface protein antigen I/II (SpaA) of Streptococcus sobrinus.

Streptococcal antigen I/II or the surface protein antigen A (SpaA) of Streptococcus sobrinus is an adhesin which mediates binding of the organism to tooth surfaces. The complete sequence of the gene which encodes SpaA has been determined. The gene consists of 4,584 bp and encodes a protein of 1,528 amino acid residues. The deduced amino acid sequence shows extensive homology with those of the cell surface adhesins from Streptococcus mutans serotypes c and f and from Streptococcus sanguis. Structural analysis of the N-terminal region (residues 50 to 550), which is rich in alanine and includes four tandem repeats of an 82-residue sequence, suggests that it adopts an alpha-helical coiled-coil conformation. Cell surface hydrophobicity may be associated with this region. The C-terminal region is more conserved and includes two tandem repeats of a 39-residue proline-rich sequence. A further proline-rich sequence in this region is predicted to span the cell wall. Although a hydrophobic sequence is present in the C-terminal region, it appears to be too short to span the cell membrane. Anchoring of SpaA in the cell membrane may therefore require some form of posttranslational modification or association with another membrane protein.

Adhesins, Bacterial↗
PubMed2001

Dextran acceptor reaction of Streptococcus sobrinus glucosyltransferase GTF-I as revealed by using uniformly 13C-labeled sucrose.

A sucrose glucosyltransferase GTF-I from cariogenic Streptococcus sobrinus transferred the uniformly 13C-labeled glucosyl residue ([U-(13)C]Glc) from [U-(13)C]sucrose to exogenous dextran T500 at the non-reducing-end, mostly by alpha-(1-->6) linkages and partially by alpha-(1-->3) linkages, as revealed by the 13C-(13)C NMR coupling pattern. With increasing amounts of [U-(13)C]sucrose, transfer of [U-(13)C]Glc to the alpha-(1-->3)-linked chain became predominant without increase in the number of chains. The transfer of [U-(13)C]Glc to an isomaltopentaose acceptor occurred similarly to its transfer to T500. alpha-(1-->3)-branches in the [U-(13)C]dextran, specifically synthesized from [U-(13)C]sucrose by a Streptococcus bovis dextransucrase, were not formed by GTF-I, as judged by the observation that a newly-formed alpha-1,3,6-branched [U-(13)C]Glc was not detected, which could have been formed by transferring the unlabeled Glc from sucrose to the internal alpha-(1-->6)-linked [U-(13)C]Glc at C-3. The 13C-(13)C one-bond coupling constants (1J) were also recorded for the C-1--C-6 bond of the internal alpha-(1-->6)-linked [U-(13)C]Glc and of the non-reducing-end [U-(13)C]Glc.

Bacterial Proteins↗
PubMed1989

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 were anesthetized, desalivated, and caged with 10 infected (donor) animals (group I). On day 36 these procedures were repeated on the remaining animals (group II). Infection was checked daily. Animals were regarded as infected when S. sobrinus was detected on 2 consecutive days and confirmed 1 week later. Animals were killed, jaws dissected, and populations of S. sobrinus and total bacterial viable count of each jaw estimated. The average number of days from pairing to detecting infection (2 consecutive days) was as follows: group I (age 25 days): desalivated 5.4 (SD 2.5), intact 8.8 (SD 4.5); group II (age 36 days): desalivated 7.8 (SD 2.9). Only 3 intact animals became infected in group II after a total elapsed time of 21 days. The mean viable counts of S. sobrinus per jaw in group 1 were as follows: desalivated 3.6 x 10(6) (SD 4.1); donor cagemate 13.0 x 10(6) (SD 9.7); intact 0.26 x 10(6) (SD 0.39); donor cagemate 4.5 x 10(6) (SD 4.3). Desalivated animals tended to be more heavily infected than intact animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

In vitro demineralization by strains of Actinomyces viscosus and Streptococcus sobrinus of sound and demineralized root surfaces.

Root sections were inoculated with one of two strains of Actinomyces viscosus or a strain of Streptococcus sobrinus and then incubated for 9 days in Trypticase soy broth (TSB) containing 0.25% glucose or TSB supplemented with 0.25% sucrose (TSB+S). Lesion progression was measured from microradiographs. One section from each group was examined with a transmission electron microscope. Lesion progression was associated with a fall in the pH of the medium. However, lesion progression was not correlated with the mean 48-hour pH of the medium. In both TSB and TSB + S, lesion progression with A. viscosus was significantly greater than in the S. sobrinus group. However, the mean 48-hour pH value in TSB + S was lower than that in the S. sobrinus group. Plaque formation in TSB was, subjectively, least in the S. sobrinus group. Examination of transmission electron micrographs revealed bacteria penetrating the surfaces of the sections and extending into the lesion in the A. viscosus groups but not in the S. sobrinus group. This in vitro bacterial plaque model of root caries may be suitable for investigations of the bacterial etiology of root-surface caries and the virulence factors associated with pathogenicity.

Actinomyces viscosus↗
PubMed2002

Effect of molecular mass and degree of deacetylation of chitosan on adsorption of Streptococcus sobrinus 6715 to saliva treated hydroxyapatite.

We evaluated the influence of molecular mass and degree of deacetylation of chitosan on the adsorption of Streptococcus sobrinus 6715 to saliva-treated hydroxyapatite (S-HA) by measuring the optical density of the bacterial cell suspensions released from saliva-treated hydroxyapatite. Twenty-five chitosan samples with different molecular masses (0.8-6 kDa) and degrees of deacetylation (10-95%) were prepared for the study. We found that the inhibition of adsorption of S. sobrinus 6715 to S-HA correlated positively with the molecular mass of chitosan (R = 0.876) and that the optimal degree of deacetylation was 50-60% for maximum inhibition of bacterial binding to S-HA. We also examined the effect of chitosan on zeta potentials of the oral bacteria and their surface hydrophobicities. It was observed that chitosan reduced the magnitude of the zeta potential and surface hydrophobicities of the oral bacteria. Thus, the results demonstrated that chitosan with a molecular mass of 5-6 kDa and a degree of deacetylation of 50-60% might have the potential to act as an effective anti-plaque agent because of its polycationic properties.

Adsorption↗
PubMed1994

Purification and characterization of Streptococcus sobrinus dextranase produced in recombinant Escherichia coli and sequence analysis of the dextranase gene.

The plasmid (pYA902) with the dextranase (dex) gene of Streptococcus sobrinus UAB66 (serotype g) produces a C-terminal truncated dextranase enzyme (Dex) with a multicomplex mass form which ranges from 80 to 130 kDa. The Escherichia coli-produced enzyme was purified and characterized, and antibodies were raised in rabbits. Purified dextranase has a native-form molecular mass of 160 to 260 kDa and specific activity of 4,000 U/mg of protein. Potential immunological cross-reactivity between dextranase and the SpaA protein specified by various recombinant clones was studied by using various antisera and Western blot (immunoblot) analysis. No cross-reactivity was observed. Optimal pH (5.3) and temperature (39 degrees C) and the isoelectric points (3.56, 3.6, and 3.7) were determined and found to be similar to those for dextranase purified from S. sobrinus. The dex DNA restriction map was determined, and several subclones were obtained. The nucleotide sequence of the dex gene was determined by using subclones pYA993 and pYA3009 and UAB66 chromosomal DNA. The open reading frame for dex was 4,011 bp, ending with a stop codon TAA. A ribosome-binding site and putative promoter preceding the start codon were identified. The deduced amino acid sequence of Dex revealed the presence of a signal peptide of 30 amino acids. The cleavage site for the signal sequence was determined by N-terminal amino acid sequence analysis for Dex produced in E. coli chi 2831(pYA902). The C terminus consists of a serine- and threonine-rich region followed by the peptide LPKTGD, 3 charged amino acids, 19 amino acids with a strongly hydrophobic character, and a charged pentapeptide tail, which are proposed to correspond to the cell wall-spanning region, the LPXTGX consensus sequence, and the membrane-anchoring domains of surface-associated proteins of gram-positive cocci.

Amino Acid Sequence↗
PubMed1992

Natural transmission of Streptococcus sobrinus in rats: saliva and serum antibody responses to colonization.

One hundred and twenty weanling rats fed diet NIH 2000 that were free of Streptococcus sobrinus and other mutans streptococci were employed in this study. Sixty rats were inoculated orally with S. sobrinus 6715. Each infected rat (donor) was paired and housed with an uninfected recipient. Saliva and serum samples were collected from 24 (12 donor and 12 recipient) rats at the baseline (day 0) and from groups of 12 recipients sacrificed on days 10, 24, 38, and 52, and the level of infection with S. sobrinus was monitored. Salivary immunoglobulin A (IgA) and IgG and serum IgM and IgG antibodies reactive with whole cells (WC), glucosyltransferase (GTF), and the serotype carbohydrate (g) of S. sobrinus were measured by an indirect enzyme-linked immunosorbent assay. Although the rats were free of S. sobrinus and other mutans streptococci at baseline, they exhibited salivary IgA and serum IgM antibodies reactive with S. sobrinus WC, GTF, and g and serum IgG antibodies reactive with WC and GTF. Infection of recipients with S. sobrinus did not induce salivary antibodies reactive with WC, GTF, or g. In contrast, increases in serum IgM and IgG antibodies reactive with WC and serum IgM antibodies reactive with g were observed.

Animals↗
PubMed2002

Evaluation of interleukin 1 as a mucosal adjuvant in immunization with Streptococcus sobrinus cells by tonsillar application in rabbits.

To evaluate interleukin 1 (IL-1) as a mucosal adjuvant in the induction of salivary antibodies to Streptococcus sobrinus, S. sobrinus together with IL-1 was applied through the palatine tonsils of rabbits. IL-1 caused approximately 50 and 100% increases in the antibodies reacting against S. sobrinus fragments in the saliva and blood plasma, respectively, compared to the antibodies in those same fluids after tonsillar applications of S. sobrinus alone. In the case of the addition of IL-1, the antibodies reacting to the protein antigens of S. sobrinus increased in each fluid, without affecting the antibodies reacting to saccharide antigens. Delayed-type hypersensitivity to S. sobrinus, characterized by ear swelling and by an increase in IFN-gamma mRNA in RT-PCR analysis, was found to be induced only in rabbits immunized with IL-1. S. sobrinus protein antigens caused ear swelling as intense as that caused by S. sobrinus fragments. Thus, IL-1 induced an antibody response and cell-mediated immunity mainly reacting to protein antigens of S. sobrinus.

Adjuvants, Immunologic↗
PubMed1987

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 recognized several forms of GTF-I and did not cross-react with the GTF-S enzymes. None of the MAbs recognized the major glucan-binding protein of S. sobrinus. Two MAbs inhibited glucan synthesis, one blocking primer synthesis by GTF-Si by 89% and the second inhibiting that by GTF-I by 92%.

Antibodies, Bacterial↗
PubMed1999

[Effect of subinhibitory concentrations of various antimicrobials on insoluble glucan production, polystyrene adherence and bacterial surface hydrophobicity of Streptococcus sobrinus].

The effect of subinhibitory concentrations (1/2, 1/4, 1/8 of the MIC) of amoxicillin, teicoplanin, clindamycin and erythromycin on the factors influencing the adherence and pathogenicity of Streptococcus sobrinus was evaluated. These factors included insoluble glucan, polystyrene adherence and bacterial surface hydrophobicity. Insoluble glucan was detected using a spectrophotometric method; polystyrene adherence was assessed using microtiter plates; and surface hydrophobicity was determined using a biphasic system (water/p-xiline). Amoxicillin and teicoplanin induced a statistically significant decrease in adherence at subinhibitory concentrations, and they also decreased the hydrophobicity. However, clindamycin and erythromycin were unable to decrease these parameters. The adherence and hydrophobicity of S. sobrinus was also dependent on the concentration of sucrose in the culture medium.

Anti-Bacterial Agents↗