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Oral Streptococci (oral + streptococcus)
Selected AbstractsRegarding neutrophil and lymphocyte responses to oral Streptococcus in Adamantiades,Behçet's diseaseFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2006Cem Evereklioglu First page of article [source] Involvement of Gln937 of Streptococcus downei GTF-I glucansucrase in transition-state stabilizationFEBS JOURNAL, Issue 13 2000Vincent Monchois Multiple alignment of deduced amino-acid sequences of glucansucrases (glucosyltransferases and dextransucrases) from oral streptococci and Leuconostoc mesenteroides has shown them to share a well-conserved catalytic domain. A portion of this domain displays homology to members of the ,-amylase family (glycoside hydrolase family 13), which all have a (,/,)8 barrel structure. In the glucansucrases, however, the ,-helix and ,-strand elements are circularly permuted with respect to the order in family 13. Previous work has shown that amino-acid residues contributing to the active site of glucansucrases are situated in structural elements that align with those of family 13. In ,-amylase and cyclodextrin glucanotransferase, a histidine residue has been identified that acts to stabilize the transition state, and a histidine is conserved at the corresponding position in all other members of family 13. In all the glucansucrases, however, the aligned position is occupied by glutamine. Mutants of glucosyltransferase I were constructed in which this glutamine, Gln937, was changed to histidine, glutamic acid, aspartic acid, asparagine or alanine. The effects on specific activity, ability to form glucan and ability to transfer glucose to a maltose acceptor were examined. Only histidine could substitute for glutamine and maintain Michaelis,Menten kinetics, albeit at a greatly reduced kcat, showing that Gln937 plays a functionally equivalent role to the histidine in family 13. This provides additional evidence in support of the proposed alignment of the (,/,)8 barrel structures. Mutation at position 937 altered the acceptor reaction with maltose, and resulted in the synthesis of novel gluco-oligosaccharides in which ,1,3-linked glucosyl units are joined sequentially to maltose. [source] Detection of oral streptococci with collagen-binding properties in saliva specimens from mothers and their childrenINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 4 2010RYOTA NOMURA International Journal of Paediatric Dentistry 2010; 20: 254,260 Background., Approximately 10,20% of Streptococcus mutans strains have been reported to possess collagen-binding properties, whereas other species in the oral cavity with those properties remain to be elucidated. Aim., To identify strains with collagen-binding properties and analyse their characteristics in comparison with S. mutans. Design., A total of 110 expectorated saliva specimens were collected from 55 pairs of mothers and their children. Bacterial strains with collagen-binding properties were isolated and the species specified. In addition, strains with collagen-binding properties isolated from mother,child pairs were analysed using molecular biological approaches. Results., The detection frequency of strains with collagen-binding properties was shown to be 40.9%, among which S. salivarius was the most frequently detected, followed by S. mutans. The collagen-binding activity of the S. mutans group was the highest, followed by S. salivarius. In addition, S. mutans and S. salivarius strains from 3 and 1 mother,child pairs, respectively, were shown to be the same clones. Conclusions., Our results indicate that S. mutans and S. salivarius are major species with collagen-binding properties in the oral cavity, and that strains with such properties may be related to mother,child transmission. [source] In vitro inhibition of oral streptococci binding to the acquired pellicle by algal lectinsJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2007E.H. Teixeira Abstract Aims:, The initial colonization of the tooth by streptococci involves their attachment to adsorbed components of the acquired pellicle. Avoiding this adhesion may be successful in preventing caries at early stages. Salivary mucins are glycoproteins that when absorbed onto hydroxyapatite may provide binding sites for certain bacteria. Algal lectins may be especially interesting for oral antiadhesion trials because of their great stability and high specificity for mucins. This work aimed to evaluate the potential of two algal lectins to inhibit the adherence of five streptococci species to the acquired pellicle in vitro. Methods and Results:, The lectins used were extracted from Bryothamnion triquetrum (BTL) and Bryothamnion seaforthii (BSL). Fluorescence microscopy was applied to visualize the ability of fluorescein isothiocyanate-labelled lectins to attach to the pellicle and revealed a similar capability for both lectins. Streptococcal adherence assays were performed using saliva-coated microtitre plates. BSL inhibited more than 75% of Streptococcus sanguis, Streptococcus mitis, Streptococcus sobrinus and Streptococcus mutans adherence, achieving 92% to the latter. BTL only obtained statistically significant results on S. mitis and S. sobrinus, whose adherence was decreased by 32·5% and 54·4%, respectively. Conclusion:, Algal lectins are able to inhibit streptococcal adherence. Significance and Impact of the Study:, Our results support the proposed application of lectins in antiadhesion therapeutics. [source] Genotypic comparison of bacteria recovered from human bite marks and teeth using arbitrarily primed PCRJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2005M. Rahimi Abstract Aims:, This study assessed, for forensic purposes, the feasibility of genotypically matching oral streptococci recovered from recent human bite marks with those from the teeth of the biter. Methods and Results:, Streptococci were isolated from the incisors of eight volunteers. Arbitrarily primed PCR (AP-PCR) distinguished 106 streptococcal genotypes among the participants, each harbouring at least eight distinct strains. In a crime simulation, a sample from an experimental bite mark was analysed by an experimenter unaware of its origin. The bacteria were unambiguously matched to the biter by comparing the amplicon profiles with those from the eight participants. In contrast, bacteria from an additional bite mark (not generated by one of the original participants) could not be matched to any of the eight participants. Between 20 and 78% of catalogued bacterial genotypes were recovered 12 months later from each participant. Throughout the study period, none of the bacterial genotypes were shared between participants. Conclusions:, Streptococci isolated from recent bite marks can be catalogued by AP-PCR and matched to the teeth responsible for the bite. Significance and Impact of the Study:, The study provides ,proof of concept' that genotypic analysis of streptococci from bite marks may provide valuable forensic evidence in situations where the perpetrator's DNA cannot be recovered. [source] Resistance to acidic and alkaline environments in the endodontic pathogen Enterococcus faecalisMOLECULAR ORAL MICROBIOLOGY, Issue 5 2006K. Nakajo Background/aims:, This study aimed to investigate the biochemical mechanisms employed by the endodontic pathogen Enterococcus faecalis to confer acid- and alkali-resistance and to compare these with the mechanisms of representative oral streptococci. Methods:,E. faecalis JCM8728, Streptococcus mutans NCTC10449 and Streptococcus sanguinis ATCC10556 were used to assess both acid- and alkali-resistance by examining: (i) growth in complex media; (ii) stability of intracellular pH (pHin); (iii) cell durability to leakage of preloaded BCECF (2,,7,-bis-(2-carboxyethyl)-5,6-carboxy-fluorescein); and (iv) cell permeability to SYTOX-Green. Results:, Growth was initiated by E. faecalis at pH 4.0,11.0, by S. mutans at pH 4.0,9.0 and by S. sanguinis at pH 5.0,9.0. The pHin was similar to the extracellular pH in S. mutans and S. sanguinis at pH 5,10, while the pHin of E. faecalis was maintained at approximately 7.5,8.5 when extracellular pH was 7.5,10 and was maintained at levels equivalent to the extracellular pH when pH < 7.5. Cell membranes of E. faecalis were resistant to BCECF leakage when extracellular pH was 2.5,12 and to SYTOX-Green permeability at pH 4,10. The cell membrane durability to extracellular pH in E. faecalis was higher than that observed in the Streptococcus strains. Conclusion:, Compared to S. mutans, E. faecalis was found to be equally resistant to acid and more resistant to alkalis. The results suggest that pH-resistance in E. faecalis is attributed to membrane durability against acid and alkali, in addition to cell membrane-bound proton-transport systems. These characteristics may account for why E. faecalis is frequently isolated from acidic caries lesions and from persistently infected root canals where calcium hydroxide medication is ineffective. [source] Low salivary IgA activity to cell-surface antigens of mutans streptococci related to HLA-DRB1*04MOLECULAR ORAL MICROBIOLOGY, Issue 2 2005M. L. L. Wallengren Background/aims:, Mutans streptococci are found in almost all individuals, though there are large differences in colonization levels between individuals. These differences are not readily explained, though several factors are believed to influence the colonization. One factor is the immune response to mutans streptococci, mainly provided by salivary immunoglobulin A (IgA). In a previous study, differences in salivary IgA reactions to oral streptococci were observed between human leukocyte antigen (HLA)-DR4-positive and DR4-negative individuals. A lower salivary IgA activity to Streptococcus mutans in particular was most pronounced for two DR4 subgroups, DRB1*0401 and *0404. The main purpose of this study was to further investigate, in a larger study group, the salivary IgA activity to antigens of three oral streptococci in relation to different HLA-DRB1*04 alleles. Methods:, Stimulated saliva was collected from 58 HLA-DRB1*04-positive individuals. Whole cell antigen extracts from S. mutans, Streptococcus sobrinus and Streptococcus parasanguis and the streptococcal antigen (SA) I/II were separated in SDS-PAGE, transblotted and detected with diluted saliva (Western blot), and analyzed in a computer program. All distinct immunoblot bands over 100 kDa were recorded and compared in relation to DRB1*04. Results:, The immunoblots revealed lower salivary IgA reactions to S. mutans, S. sobrinus and SA I/II, but not to S. parasanguis, for the DRB1*0401- and *0404-positive individuals compared to other DRB1*04 types. For the *0401 subgroup there was a significant association with a lower IgA response to S. mutans. Conclusion:, The results confirm earlier observations and may also support previous demonstrated association between colonization by mutans streptococci and the serologically defined HLA-DR4. [source] Inhibitory effects of cranberry juice on attachment of oral streptococci and biofilm formationMOLECULAR ORAL MICROBIOLOGY, Issue 3 2004A. Yamanaka Cranberry juice is known to inhibit bacterial adhesion. We examined the inhibitory effect of cranberry juice on the adhesion of oral streptococci strains labeled with [3H]-thymidine to saliva-coated hydroxyapatite beads (s-HA). When the bacterial cells were momentarily exposed to cranberry juice, their adherence to s-HA decreased significantly compared with the control (P < 0.01). Their hydrophobicity also decreased dependently with the concentration of cranberry juice. We also evaluated the inhibitory effect of cranberry juice on biofilm formation. By using a microplate system, we found that the high molecular mass constituents of cranberry juice inhibited the biofilm formation of the tested streptococci. The inhibitory activity was related to the reduction of the hydrophobicity. The present findings suggest that cranberry juice component (s) can inhibit colonization by oral streptococci to the tooth surface and can thus slow development of dental plaque. [source] Crystallization and preliminary X-ray analysis of ,C,S lyases from two oral streptococciACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2009Yuichiro Kezuka Hydrogen sulfide, which causes oral malodour, is generally produced from l -cysteine by the action of ,C,S lyase from oral bacteria. The ,C,S lyases from two oral bacteria, Streptococcus anginosus and S. gordonii, have been cloned, overproduced, purified and crystallized. X-ray diffraction data were collected from the two types of crystals using synchrotron radiation. The crystal of S. anginosus,C,S lyase belonged to the orthorhombic space group P212121, with unit-cell parameters a = 67.0, b = 111.1, c = 216.4,Å, and the crystal of S. gordonii,C,S lyase belonged to the same space group, with unit-cell parameters a = 58.0, b = 73.9. c = 187.6,Å. The structures of the ,C,S lyases were solved by molecular-replacement techniques. [source] | |||||||||||||