Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Streptococcus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1976

Antagonistic action of Streptococcus salivarius and Streptococcus faecalis to Mycobacterium tuberculosis.

Streptococcus salivarius and Streptococcus faecalis were found to inhibit the growth of Mycobacterium tuberculosis on Löwenstein-Jensen and Middlebrook 7H11 agars, but not on the latter medium when antibacterial drugs were added. S. faecalis was found to be more inhibitory than S. salivarius to 15 strains of M. tuberculosis. S. salivarius produced little or no inhibition of growth of Runyon group III organisms but was very antagonistic to Runyon group I mycobacteria.

Agar↗
PubMed1977

Transfection of Streptococcus sanguis by phage deoxyribonucleic acid isolated from Streptococcus mutans.

Streptococcus sanguis ATCC 10556 cells were infected with free phage DNA of S, mutans strain PK 1. Two transformants were isolated which made colonies with large mucoid forms on mitis-salivarius agar. Both transformants had an increased ability to synthesize insoluble glucan and showed an adhesive nature on glass surfaces. These characteristics of the transformants bear a resemblance to S. mutans. These transformants had many physiological characteristics by which they could be recognized as S. sanguis. However, they resembled S. salivarius in forming a large amount of soluble fructan. Furthermore, the transformant cells did not produce ammonia from arginine, whereas their parent cells did.

Bacteriolysis↗
PubMed1977

Molecular basis for the different sucrose-dependent adherence properties of Streptococcus mutans and Streptococcus sanguis.

The enzymatic and adherence properties of Streptococcus mutans GS5 and S. sanguis ST3, both isolated from human carious lesions, have been compared. During growth in sucrose media, S. mutans GS5 adheres to smooth surfaces approximately three times more effectively than dose S. sanguis ST3. However, strain ST3 does not display sucrose-dependent adherence under nongrowth conditions, whereas strain GS5 displays significant adherence. Although both organisms synthesize both water-soluble and -insoluble glucans, the glucosyltransferases from S. mutans GS5 synthesize much more adherent glucan molecules than do the comparable enzymes from S. sanguis ST3. Both cell types bind exogenous glucosyltransferases synthesized by strain ST3 equally well, whereas cells of strain GS5 bind the comparable enzyme fraction that it synthesizes to a greater degree than do cell of S. sanguis ST3. However, in contrast to the results with cells of S. mutans GS5, the absorption of the glucosyltransferase activity synthesized by S. mutans GS5 to the surface of S. sanguis ST3 results in low levels of subsequent sucrose-dependent adherence. These results are discussed in terms of the molecular basis for the sucrose-dependent adherence of the oral streptococci to smooth surfaces.

Adhesiveness↗
PubMed1978

Specificity of salivary-bacterial interactions: role of terminal sialic acid residues in the interaction of salivary glycoproteins with Streptococcus sanguis and Streptococcus mutans.

Four highly purified salivary glycoproteins were used to study salivary-bacterial interactions. One pair of glycoproteins was mucin-like in composition, whereas the second pair was not. By an agglutination assay, it was found that only the mucin-glycoproteins agglutinated Streptococcus sanguis and S. mutans. Removal of sialic acid from these molecules resulted in a loss of agglutination of S. sanguis but not of S. mutans. The agglutination phenomenon was shown to require a salivary macromolecule of at least 150,000 daltons.

Agglutination↗
PubMed1978

Isolation and characterization of a Streptococcus mutans bacteriocin inhibitor from Streptococcus pyogenes.

An inhibitor of Streptococcus mutans strain GS5 bacteriocin was released from a bacteriocin-sensitive strain of S. pyogenes by sonic treatment and partly purified by gel filtration on a Sepharose 6B column. The inhibitory factor was sensitive to heat, trypsin, and periodate and possessed a molecular weight of approximately 93,000. This factor may be the receptor for the S. mutans bacteriocin.

Bacterial Proteins↗
PubMed1978

Effects of local immunization with glucosyltransferase fractions from Streptococcus mutans on dental caries in hamsters caused by homologous and heterologous serotypes of Streptococcus mutans.

Seven serotypes of Streptococcus mutans have been identified. The biochemical, genetic, and serological characteristics of these serotypes have indicated that certain serotypes are quite similar, whereas others are quite distinct. The effect of local immunization with glucosyltransferase (GTF) enzymes from serotypes a, c, or g on infection and disease caused by homologous or heterologous cariogenic S. mutans is reported. Organisms with either similar (a and g) or different (c and g) biochemical and serological characteristics were selected for heterologous challenge. NIH white hamsters were injected four times at weekly intervals with GTF prepared by 6 M guanidine-hydrochloride elution from water-insoluble glucan of serotypes a, c, or g, which resulted in enzyme (homologous) inhibitory activity in sera and salivas. After infection of GTF-immunized and sham-immunized groups of hamsters with cariogenic S. mutans of the same serotype as the injected antigen (homologous infection) or with S. mutans of a different serotype from the injected antigen (heterologous infection), the numbers of streptomycin-labeled S. mutans, caries, and lesions were determined. Immunization with GTF preparations from each of the three serotypes resulted in statistically significant reductions in the extent of infection and disease and number of lesions caused by infections with homologous cariogenic S. mutans. Statistically significant reductions in these three parameters were also observed in groups immunized with enzyme from serotype a (strain E49) and challenged with cariogenic serotype g (strain 6715) organisms; or immunized with enzyme from serotype c (strain Ingbritt) and challenged with cariogenic serotype g (strain 6715) organisms; or immunized with enzyme from serotype g (strain 6715) and challenged with cariogenic serotype c (strain Ingbritt) organisms. These studies suggest that soluble antigen preparations containing GTF from one serotype may elicit a protective immune response against infection with cariogenic S. mutans from many or possibly all serotypes.

Animals↗
PubMed1978

Brain abscess due to Streptococcus MG-intermedius (Streptococcus milleri).

Three cases of brain abscesses due to Streptococcus MG-intermedius are reported, and the literature pertaining to this subject is reviewed. The importance of careful and complete identification of these etiological agents of infection is stressed. The clinical presentation, the origin of S. MG-intermedius producing brain abscess, and its relation to hepatic abscesses and endocarditis are discussed.

Adolescent↗
PubMed1979

Enzymatic deacylation of lipoteichoic acid by protoplasts of Streptococcus faecium (Streptococcus faecalis ATCC 9790).

High-molecular-weight, micellar lipoteichoic acid (LTA) was converted to a lower-molecular-weight, apparently deacylated polymer when the former was incubated in the presence of growing protoplasts of Streptococcus faecium (S. faecalis ATCC 9790), but not when incubated in fresh or spent protoplast medium. The mobility of the low-molecular-weight polymer upon agarose gel electrophoresis was indistinguishable from that of native extracellular lipoteichoic acid LTA(X) from this organism or from chemically deacylated LTA. Native LTA(X) was shown to contain less than one fatty acid equivalent per 18 LTA(X) molecules, in contrast to the 4:1 ratio of fatty acids to polyglycerolphosphate chains in micellar LTA.

Enterococcus faecalis↗
PubMed1977

Interaction of hydroxyapatite and protein-coated hydroxyapatite with Streptococcus mutans and Streptococcus sanguis.

The present study showed that S. mutans and S. sanguis behaved like negatively-charged particles in their interaction with hydroxyapatite in vitro. Phosphate in the system inhibited bacterial uptake by apatite, whereas calcium increased the uptake. A layer of acidic protein inhibited the uptake of bacteria by hydroxyapatite. The opposite was true when a basic protein was first adsorbed to the apatite. A saliva film on the apatite decreased the uptake of bacteria, supporting the view that acidic proteins are selectively adsorbed by hydroxyapatite from saliva. The results indicate clearly that electrostatic forces may be involved in bacterial interaction with tooth surface.

Adsorption↗
PubMed1976

[The immunobiology of M-proteins of Streptococcus pyogenes. I. Isolation and purification of M-proteins from group A streptococci (Streptococcus pyogenes) type 1].

Streptococci of group A, type 1, are lysed by use of phage associated lysin, which is characterized as a N-Acetyl-D-glucosaminidase. This enzyme has no proteolytic activity. Type specific protein antigens are isolated and purified by ion exchange chromatography on CM-cellulose and DEAE-cellulose of the crude extract, concentrated by precipitation with ammonium sulfate. The immunization tests are carried out on monkeys and rabbits.

Animals↗