| immunological relationships between glucosyltransferases synthesizing insoluble glucan from streptococcus cricetus, streptococcus sobrinus and streptococcus downei. | the mr values and isoelectric points of glucosyltransferases synthesizing insoluble glucan (gtf-is) were determined, and the immunological relationships between them studied. the gtf-i enzymes were from streptococcus cricetus (mutans group serotype a), streptococcus sobrinus (mutans group serotypes d and g) and streptococcus downei (mutans group serotype h). by double immunodiffusion tests, the gtf-i enzymes from the three species possessed a common antigenic determinant; in addition, the gtf-i ... | 1991 | 1720167 |
| structural properties and evolutionary relationships of pspa, a surface protein of streptococcus pneumoniae, as revealed by sequence analysis. | analysis of the sequence for the gene encoding pspa (pneumococcal surface protein a) of streptococcus pneumoniae revealed the presence of four distinct domains in the mature protein. the structure of the n-terminal half of pspa was highly consistent with that of an alpha-helical coiled-coil protein. the alpha-helical domain was followed by a proline-rich domain (with two regions in which 18 of 43 and 5 of 11 of the residues are prolines) and a repeat domain consisting of 10 highly conserved 20-a ... | 1992 | 1729249 |
| a family of clostridial and streptococcal ligand-binding proteins with conserved c-terminal repeat sequences. | analysis of the derived amino acid sequences of toxins a and b from clostridium difficile has identified an extraordinarily large number of repeat amino acid units in the c-terminal regions of the proteins. nearly one third of each of the proteins consist of repeating units which appear, at least in the case of toxin a, to be responsible for carbohydrate binding. similar repeat units are also found in the c-terminal region of four glucosyltransferases from streptococcus mutans and streptococcus ... | 1991 | 1830357 |
| cloning of a streptococcus sobrinus gtf gene that encodes a glucosyltransferase which produces a high-molecular-weight water-soluble glucan. | the gtf gene coding for glucosyltransferase (gtf), which produces a water-soluble glucan, was cloned from streptococcus sobrinus omz176 (serotype d) into plasmid vector pbr322. this gene was expressed in escherichia coli, and the product was purified to near homogeneity. the antigenicity of recombinant gtf (rgtf) was examined with the antisera raised against purified gtf p1, p2, p3, and p4 obtained from s. sobrinus aht (serotype g). the rgtf reacted only with anti-gtf p1 serum in a western blot ... | 1991 | 1832662 |
| enzyme immunoassay and monoclonal antibodies for immunological studies of the mutans group of streptococci. | monoclonal antibodies (mabs) were prepared from myeloma cells and splenocytes of mice immunized with streptococcus cricetus hs1 or streptococcus downei mf25 cells. various makes of immunoplates were coated with whole cells or purified polysaccharide antigens of oral streptococcal strains and tested for reactivity in enzyme immunoassay (eia) using the mabs. it was revealed that different immunoplates had different reactivities. it was also shown that the eia system and mabs were useful for the im ... | 1990 | 2099287 |
| 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 ... | 1990 | 2142479 |
| 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 ... | 1990 | 2148181 |
| nucleotide sequence of the streptococcus mutans gtfd gene encoding the glucosyltransferase-s enzyme. | the nucleotide sequence of the streptococcus mutans gs-5 gtfd gene coding for the glucosyltransferase which synthesizes water-soluble glucan (gtf-s) has been determined. the complete gene contains 4293 base pairs and the unprocessed protein is composed of 1430 amino acids with a molecular mass of 159814 da. the amino terminus of the unprocessed protein resembles the signal sequences of other extracellular proteins secreted by s. mutans and that of the gtf-i secreted by streptococcus downei. in a ... | 1990 | 2148600 |
| 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 ... | 1989 | 2761390 |
| calcium and water diffusion in single-species model bacterial plaques. | the diffusion of tritiated water and 45ca through single-species model plaques was measured in a diaphragm cell. using plaques of streptococcus downei, the apparent diffusion coefficient for tritiated water showed a small but significant decrease between ph 7.0 and 5.0 with a smaller, non-significant decrease for calcium. these effects are attributed to possible plaque shrinkage at reduced ph, which overcomes effects due to charge-dependent changes in permeability. effective diffusion coefficien ... | 1995 | 7639641 |
| a quantitative study of calcium binding by isolated streptococcal cell walls and lipoteichoic acid: comparison with whole cells. | calcium-binding by surface components of oral bacteria may have important effects on remineralization/demineralization phenomena and plaque cohesion. additionally, some species export large quantities of lipoteichoic acid, possibly as a protective measure. measurement of calcium-binding can facilitate prediction of how this will effectively buffer plaque fluid calcium concentration and affect these processes. using equilibrium dialysis, we measured calcium-binding capacities and affinities at ph ... | 1994 | 7983261 |
| immunochemical study of polysaccharide antigen in streptococcus sobrinus and streptococcus downei with a cross-reactive monoclonal antibody. | a monoclonal antibody (mab h-448) was prepared after cell fusion of mouse myeloma cells (sp2/0-ag-14) to the spleen cells of mice immunised with serotype h strain (mf25) of streptococcus downei. the antibody (igm class) reacted in enzyme immunoassay only with whole cells as well as purified polysaccharide (ps) antigen of streptococcus sobrinus (types d and g) and streptococcus downei (serotype h), but not with cells or purified ps antigen from any other serotypes of the mutans group of streptoco ... | 1994 | 8004057 |
| dna sequence of the glucosyltransferase gene of serotype d streptococcus sobrinus. | a glucosyltransferase (gtf) gene was cloned into escherichia coli from serotype d streptococcus sobrinus omz176. transformed e. coli strain mi expressed water-insoluble glucan synthesizing activity. restriction enzyme map of pgt31 extracted from mi shows that the enzyme gene exists in the 6.4-kb psti-fragment inserted into pbr322 vector. dna sequence analysis indicates that a single orf (530-5,300) is located in the psti-fragment. the putative amino-acid composition (1,590 residues) resembles th ... | 1993 | 8312602 |
| expression and secretion of an arthrobacter dextranase in the oral bacterium streptococcus gordonii. | we have constructed a plasmid to express and secrete dextranase in the oral bacterium streptococcus gordonii. the dextranase gene from arthrobacter sp. strain cb-8 was linked to a promoter and a dna sequence encoding the signal peptide of streptococcus downei glucosyltransferase i (gtfi) followed by the escherichia coli rrnbt1t2 terminator and inserted in the shuttle vector pva838. s. gordonii transformed with this plasmid (pmnk-4) expressed and secreted mature arthrobacter dextranase. the trans ... | 1993 | 8406828 |
| expression of gtfs is essential for normal insoluble glucan synthesis by streptococcus downei. | the gtfi and gtfs genes of streptococcus downei were investigated to determine the contribution of the respective enzymes to glucan production in the presence and absence of other glucosyltransferases. extracts of escherichia coli expressing cloned gtfs produced a short linear dextran from sucrose which could act as a primer for insoluble glucan synthesis when mixed with extracts of a strain expressing recombinant gtfi. to elucidate the contribution of gtfs to glucan production by s. downei, a m ... | 1993 | 8454327 |
| nucleotide sequence analysis of the gtft gene from streptococcus sobrinus omz176. | the gtft gene and its upstream region isolated from the streptococcus sobrinus omz176 chromosomal dna were sequenced. the gtft gene was preceded by a potential shine-dalgarno sequence. the gtft gene product, glucosyltransferase (gtf), displays a typical gram-positive bacterial signal peptide sequence and both an active site peptide sequence and carboxy-terminal repeats typical of gtfs. the signal sequence is similar to those of other known gtf proteins. the putative active-site peptide sequence ... | 1993 | 8478099 |
| knowledge-based model of a glucosyltransferase from the oral bacterial group of mutans streptococci. | mutans streptococci glucosyltransferases catalyze glucosyl transfer from sucrose to a glucan chain. we previously identified an aspartyl residue that participates in stabilizing the glucosyl transition state. the sequence surrounding the aspartate was found to have substantial sequence similarity with members of alpha-amylase family. because little is known of the protein structure beyond the amino acid sequence, we used a knowledge-based interactive algorithm, macaw, which provided significant ... | 1997 | 9416598 |
| isolation of an active catalytic core of streptococcus downei mfe28 gtf-i glucosyltransferase. | truncated variants of gtf-i from streptococcus downei mfe28 were purified by means of a histidine tag. sequential deletions showed that the c-terminal domain was not directly involved in the catalytic process but was required for primer activation. a fully active catalytic core of only 100 kda was isolated. | 1999 | 10094712 |
| effect of inactivation of gtf genes on adherence of streptococcus downei. | the activity of glucosyltransferases (gtf), a group of enzymes that synthesize water-soluble and -insoluble glucans from sucrose, significantly contributes to the cariogenicity of mutans streptococci. streptococcus downei produces four glucosyltransferases, gtfi, which produces insoluble glucan, and gtfs, gtft, and gtfu, which synthesize soluble glucans. we have previously reported that inactivation of gtfs results in altered adherence and have now examined its interaction with other enzymes by ... | 1999 | 10204477 |
| secondary structure of streptococcus downei gtf-1 glucansucrase. | multiple sequence alignment and structure prediction of glucansucrases produced by oral streptococci and leuconostoc mesenteroides showed that all have common structural features, with three major domains. there is no conservation of primary sequence or structure in the n-terminal variable region. sequence-based structure prediction combined with circular dichroism spectrum analysis of purified truncated forms of streptococcus downei gtf-i revealed that the core catalytic region has a defined st ... | 1999 | 10474191 |
| isolation of key amino acid residues at the n-terminal end of the core region streptococcus downei glucansucrase, gtf-i. | related streptococcal and leuconostoc mesenteroides glucansucrases are enzymes of medical and biotechnological interest. molecular modelling has suggested that the catalytic domain contains a circularly permuted version of the (beta/alpha)8 barrel structure found in the amylase superfamily, and site-directed mutagenesis has identified critical amino acids in this region. in this study, sequential n-terminal truncations of streptococcus downei gtf-i showed that key amino acids are also present in ... | 1999 | 10570812 |
| mutagenesis of asp-569 of glucosyltransferase i glucansucrase modulates glucan and oligosaccharide synthesis. | glucansucrases of oral streptococci and leuconostoc mesenteroides are enzymes of medical and biotechnological interest that synthesize alpha-glucans. they can also synthesize oligosaccharides in the presence of a sugar acceptor. previous reports have identified an amino acid residue that may affect the structure of the glucan product; therefore, random mutagenesis of the corresponding asp-569 of streptococcus downei glucosyltransferase i (gtf-i) was used to further understanding of its involveme ... | 2000 | 10788361 |
| nucleotide sequence and molecular characterization of a dextranase gene from streptococcus downei. | dna fragments encoding the streptococcus downei dextranase were amplified by pcr and inverse pcr based on a comparison of the dextranase gene (dex) sequences from s. sobrinus, s. mutans, and s. salivarius, and the complete nucleotide sequence of the s. downei dex was determined. an open reading frame (orf) of dex was 3,891 bp long. it encoded a dextranase protein (dex) consisting of 1,297 amino acids with a molecular mass of 139,743 da and an isoelectric point of 4.49. the deduced amino acid seq ... | 2001 | 11471821 |
| an essential amino acid residue for catalytic activity of the dextranase of streptococcus mutans. | dextranase (dex) is an enzyme that hydrolyzes glucan, a polymer of glucose synthesized from sucrose by glucosyltransferases (gtfs). by comparing amino acid sequences of dexs and gtfs, we found that the dex enzymes of streptococcus mutans, streptococcus sobrinus, streptococcus downei and streptococcus salivarius had similar amino acid sequences to those of the catalytic sites of gtfs of mutans streptococci. we therefore examined the amino acid essential in dex catalysis by molecular genetic appro ... | 2002 | 12030973 |
| classification of oral streptococci by two-dimensional gel electrophoresis with direct activity stain for glycosyltransferases. | thirty eight strains of oral streptococci were divided into six types by two-dimensional gel electrophoresis (2-de) followed by glycosyltransferase (glt) activity stain: type 1, streptococcus mutans; type 2, streptococcus rattus; type 3, streptococcus sobrinus and streptococcus downei; type 4, streptococcus cricetus; type 5, streptococcus salivarius; and type 6, streptococcus sanguis, streptococcus oralis and streptococcus gordonii. in types 1, 2 and 5, two glucosyltransferases synthesizing wate ... | 2003 | 12753469 |
| species-specific pcr method for identification of streptococcus downei. | to establish a rapid method to differentiate streptococcus downei and s. sobrinus by multiplex pcr. | 2004 | 14746543 |
| molecular characterization of dextranase from streptococcus rattus. | the complete nucleotide sequence of the dextranase gene of streptococcus rattus atcc19645 was determined. an open reading frame of the dextranase gene was 2,760 bp long and encoded a dextranase protein consisting of 920 amino acids with a molecular weight of 100,163 da and an isoelectric point of 4.67. the s. rattus dextranase purified from recombinant escherichia coli cells showed dextran-hydrolyzing activity with optimal ph (5.0) and temperature (40 c) similar to those of dextranases from stre ... | 2004 | 15031528 |
| first isolation of streptococcus downei from human dental plaques. | in this study, we isolated four bacterial strains grown on mitis-salivarius sucrose bacitracin agar. the strains had similar biochemical characteristics to biotypes i or ii of mutans streptococci. the four isolates were identified as streptococcus downei by 16s rdna and dextranase gene (dex) sequencing as well as polymerase chain reaction-restriction fragment length polymorphism (pcr-rflp) targeting dex. to our knowledge, this is the first report of the isolation and identification of s. downei ... | 2005 | 16002238 |
| differentiation of mutans streptococci by intact cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. | it is difficult to distinguish mutans streptococci on the species level, and even more so on the subspecies level. intact cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (maldi-tof-ms) (icm) was applied to reference strains of five of the species of the mutans group (streptococcus criceti, streptococcus downei, streptococcus mutans, streptococcus ratti, streptococcus sobrinus), nonmutans streptococci (streptococcus oralis, streptococcus mitis, streptococcus sali ... | 2005 | 16101961 |
| mutan produced in potato amyloplasts adheres to starch granules. | production of water-insoluble mutan polymers in kardal potato tubers was investigated after expression of a full-length (gtfi) and a truncated mutansucrase gene referred to as gtficat (gtfi without glucan-binding domain) from streptococcus downei. subsequent effects on starch biosynthesis at the molecular and biochemical levels were studied. expression of the gtficat gene resulted in the adhesion of mutan material on starch granules, which stained red with erythrosine, and which was hydrolysed b ... | 2005 | 17129316 |
| identification and characterization of an autolysin gene, atlh, from streptococcus downei. | an autolysin gene, atlh, was identified and sequenced from streptococcus downei mfe28 using degenerate polymerase chain reaction (pcr) and the gene-walking method. atlh protein encoded by atlh is composed of 879 amino acids, with a molecular weight of 95,902.26. atlh possesses four 15-amino-acid residue repeats in the putative cell-wall-binding domain and has a catalytic domain in the c-terminus. the deduced amino acid sequence of atlh showed homology to s. mutans autolysin atla (68.4% similarit ... | 2009 | 19093149 |
| pH landscapes in a novel five-species model of early dental biofilm. | Despite continued preventive efforts, dental caries remains the most common disease of man. Organic acids produced by microorganisms in dental plaque play a crucial role for the development of carious lesions. During early stages of the pathogenetic process, repeated pH drops induce changes in microbial composition and favour the establishment of an increasingly acidogenic and aciduric microflora. The complex structure of dental biofilms, allowing for a multitude of different ecological environm ... | 2011 | 21966490 |
| osteopontin reduces biofilm formation in a multi-species model of dental biofilm. | combating dental biofilm formation is the most effective means for the prevention of caries, one of the most widespread human diseases. among the chemical supplements to mechanical tooth cleaning procedures, non-bactericidal adjuncts that target the mechanisms of bacterial biofilm formation have gained increasing interest in recent years. milk proteins, such as lactoferrin, have been shown to interfere with bacterial colonization of saliva-coated surfaces. we here study the effect of bovine milk ... | 2012 | 22879891 |
| distribution of streptococcus troglodytae and streptococcus dentirousetti in chimpanzee oral cavities. | the aim of this study was to analyze the distribution and phenotypic properties of the indigenous streptococci in chimpanzee (pan troglodytes) oral cavities. eleven chimpanzees (aged from 9 to 44 years, mean ± sd, 26.9 ± 12.6 years) in the primate research institute of kyoto university were enrolled in this research and brushing bacterial samples collected from them. streptococci were isolated from the oral cavities of all chimpanzees. the isolates (n = 46) were identified as thirteen species by ... | 2013 | 23668608 |
| cryptic streptococcus mutans 5.6-kb plasmids encode a toxin-antitoxin system for plasmid stabilization. | in all streptococcus mutans strains, 5-13% carry a 5.6-kb plasmid. despite its frequency, little is known about its mediated functions with most of the information coming from a single study focussing on plasmid pua140. | 2013 | 23330057 |
| gbpc gene repertoire variation among mutans streptococci. | the human dental caries pathogen streptococcus mutans harbors one glucan-binding wall-anchored protein gene, gbpc, and another human pathogen, streptococcus sobrinus, has 4 gbpc homologues. as no 4 gbpc homologues have so far been detected in other mutans streptococci, however, we cannot say whether those in s. sobrinus are paralogous or orthologous. therefore, the purpose of this study was to identify and sequence the gbpc/dbl genes in streptococcus downei and streptococcus criceti. the finding ... | 2012 | 22790333 |
| streptococcus troglodytae sp. nov., from the chimpanzee oral cavity. | six strains, tku 25, tku 28, tku 30, tku 31(t), tku 33 and tku 34, were isolated from the oral cavity of a chimpanzee (pan troglodytes). colonies of strains grown on mitis-salivarius agar were similar in morphology to that of streptococcus mutans. the novel strains were gram-stain-positive, facultatively anaerobic cocci that lacked catalase activity. analysis of the partial 16s rrna gene sequences of these isolates showed that the most closely related strain was the type strain of s. mutans (96. ... | 2013 | 22447699 |
| secretion of functional salivary peptide by streptococcus gordonii which inhibits fimbria-mediated adhesion of porphyromonas gingivalis. | porphyromonas gingivalis, a putative periodontopathogen, can bind to human salivary components with its fimbriae. we have previously shown that fimbriae specifically bind to a peptide domain shared by a major salivary component, i.e., proline-rich (glyco)proteins (prps). the synthetic domain peptide prp-c (pprp-c) significantly inhibits the fimbrial binding to prps. in this study, a recombinant strain of streptococcus gordonii secreting pprp-c was generated as a model of a possible approach to p ... | 1999 | 10417138 |
| real-time pcr for quantification of streptococcus mutans. | a real-time polymerase chain reaction (pcr) assay was developed for the quantification of streptococcus mutans. primers targeting gtf genes of s. mutans were designed and tested for their specificity using 28 oral streptococcal strains, three other bacterial strains, and human dna. the primers could amplify specifically the target dna fragment from a mixture of oral streptococcus genomic dna containing about 10 fg to 10 ng of s. mutans genome dna. the real-time pcr produced a linear quantitative ... | 2002 | 12445641 |
| involvement of gln937 of streptococcus downei gtf-i glucansucrase in transition-state stabilization. | 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 alpha-amylase family (glycoside hydrolase family 13), which all have a (beta/alpha)8 barrel structure. in the glucansucrases, however, the alpha-helix and beta-strand elements are circularly permuted with respect to ... | 2000 | 10866815 |
| a dna probe specific to streptococcus sobrinus. | three dna fragments (ssb-1, -2 and -3) in the dextranase gene (dex) of streptococcus sobrinus were amplified by polymerase chain reaction and used as dna probes. the probes were examined for the specificity and the sensitivity of hybridization with dna of oral streptococcal species. while probes ssb-1 and ssb-2 were specific to both s. sobrinus and streptococcus downei, ssb-3 was specific only to s. sobrinus. ssb-3 was able to detect 5 ng of chromosomal dna purified from s. sobrinus nidr6715 and ... | 1999 | 10551167 |
| identification of mutans streptococci by restriction fragment length polymorphism analysis of polymerase chain reaction-amplified 16s ribosomal rna genes. | mutans streptococci are frequently isolated from dental plaque and carious lesions. these bacteria have been identified by conventional methods such as biochemical and serologic tests followed by the isolation of colonies on the mitis-salivarius agar, which are sometimes inconsistent. recently, species-specific polymerase chain reaction (pcr) has been reported to rapidly identify streptococcus mutans and streptococcus sobrinus. however, in the case of identification and classification into sever ... | 2003 | 12930526 |
| Rapid detection and identification of Streptococcus ratti by a species-specific PCR method. | To establish a rapid and species-specific detection and identification method of Streptococcus ratti by polymerase chain reaction, two PCR primer pairs specific to S. ratti were designed on the basis of the nucleotide sequence of the dextranase gene (dex) of S. ratti ATCC19645(T). The primer pairs specifically detected S. ratti, but none of the other mutans streptococci (16 strains of 6 species). The PCR procedure was capable of detecting 1 pg of genomic DNA purified from S. ratti ATCC19645. We ... | 2011 | 21924372 |
| identification and characterization of an antigen i/ii homologous gene, pah, from streptococcus downei. | antigen i/ii of streptococcus mutans is a cell surface protein involved in the adherence of cells to tooth surfaces. in this study, an antigen i/ii homologous gene, pah, was identified and sequenced from streptococcus downei mfe28 using degenerate polymerase chain reaction (pcr) and the gene-walking method. the pah gene encodes a cell-wall-anchoring protein, pah, containing 1565 amino acids. at the deduced amino acid sequence level, pah shows a strong similarity to pag of s. sobrinus (97.6% iden ... | 2008 | 18283515 |
| conserved repeat motifs and glucan binding by glucansucrases of oral streptococci and leuconostoc mesenteroides. | glucansucrases of oral streptococci and leuconostoc mesenteroides have a common pattern of structural organization and characteristically contain a domain with a series of tandem amino acid repeats in which certain residues are highly conserved, particularly aromatic amino acids and glycine. in some glucosyltransferases (gtfs) the repeat region has been identified as a glucan binding domain (gbd). such gbds are also found in several glucan binding proteins (gbp) of oral streptococci that do not ... | 2004 | 15576779 |