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At least 19 recordsLinked to original sources
PubMed1978

Inhibitory effects of extracellular products from oral bacteria on human fibroblasts and stimulated lymphocytes.

Extracellular products of 12 strains of Streptococcus mutans and 5 additional species of oral bacteria were analyzed for their ability to inhibit proliferation of fibroblastoid cells (HeLa and AV3) and blast transformation of human peripheral blood lymphocytes obtained from normal individuals. Products from S. mutans strains AHT and BHT, Streptococcus intermedius, and Actinomyces viscosus inhibited [3H]thymidine uptake by fibroblastoid cells and phytohemagglutinin-stimulated lymphocytes. Products from S. mutans E49, Streptococcus salivarius, and Actinomyces naeslundii inhibited blast transformation of human lymphocytes but did not significantly inhibit the growth of fibroblastoid cells. Preparations from S. intermedius gave the greatest inhibitory activity against both target cell types; initial characterization of this preparation suggested a single factor active in both assays, in that the heat lability and Sephadex G-200 elution profile were similar for the inhibitory activity seen with the two cell types. The molecular weight of the inhibitor, estimated by gel filtration on Sephadex G-200 and Ultragel AcA34, was approximately 160,000. The results strongly suggest that oral bacteria produce heat-labile substances that interfere with fibroblast proliferation and alter the lymphocytic immunological response.

Actinomyces↗
PubMed1979

Inhibitory activity of Streptococcus mitis against oral bacteria.

The antagonistic properties of three strains of Streptococcus mitis were investigated. They were found to inhibit a wide range of oral bacteria; Gram-positive and Gram-negative, facultative and anaerobic species being susceptible. The S. mitis strains were shown to be producing hydrogen peroxide, this being partially responsible for the aerobic inhibitory activity. A second inhibitory factor(s) was also produced, aerobically and anaerobically, although this could not be isolated. A limited characterization of this factor was undertaken using plate cultures.

Actinomycetaceae↗
PubMed1977

Interdependence of in vitro responsiveness of cord and maternal blood lymphocytes to antigens from oral bacteria.

A group of thirty-five mothers and their babies at parturition were examined by the in vitro lymphocyte transformation test to determine sensitization by oral bacterial antigens, B-cell mitogens and dental plaque. Lymphocytes from babies of sensitized mothers with gingival or periodontal disease gave the highest frequency (70 and 63%) and magnitude (mean stimulation index of 3.4 and 3.3) of response in cultures stimulated by Actinomyces viscosus and Veillonella alcalescens. However, IgM antibodies to V. alcalescens antigen were absent from cord sera. With one exception, stimulation of lymphocytes from babies of unsensitized mothers with clinically healthy gingiva was not found with these antigens. The response of cord lymphocytes from mothers with gingival or periodontal disease to antigens from oral bacteria, as compared with the response of cord lymphocytes from mothers with clinically healthy gingiva, seemed specific, since a corresponding difference in response to unrelated antigen PPD was not found. The response of cord and maternal lymphocytes to B-cell mitogens was also determined. Maternal lymphocytes responded in the following decreasing order of effectiveness: dextran sulphate, levan, lipopolysaccharide and dextran B1355; whereas cord lymphocytes were stimulated in the reverse order of effectiveness.

Adolescent↗
PubMedDate not supplied

Inhibition and killing of oral bacteria by silver ions generated with low intensity direct current.

Silver cations generated by passing low intensity direct current through pure silver electrodes were found to be sufficiently antibacterial to cause sterilization of samples of infected dentin. The optimal procedure involved a 5 microA current applied for 20 minutes with the anode then left in contact with the sample. Minimal inhibitory concentrations of electrically generated silver ions for representative oral bacteria were essentially equal to those for silver ions added as nitrate or fluoride salts, and medium constituents, including sodium thioglycolate, antagonized antibacterial action. A major advantage to the use of the electrode method is that it allows for continuous, focal application of antibacterial silver cations.

Bacteria↗
PubMed1979

Phospholipid composition of gliding bacteria: oral isolates of Capnocytophaga compared with Sporocytophaga.

The distribution of acetone-soluble (neutral glycolipid) and acetone-insoluble (phospholipid isoprenoids) lipids in oral isolates of gram-negative gliding bacteria of the genus Capnocytophaga was compared with those in a non-host-related gliding bacterium, Sporocytophaga myxococcoides. The acetone-soluble material accounted for 34 to 55% of the extracted lipids; the remainder was acetone-insoluble material. The major phospholipid was phosphatidylethanolamine (67%), with lesser amounts of lysophosphatidylethanolamine and several unidentified phosphate-containing compounds. Capnocytophaga also contained significant amounts of an ornithine-amino lipid.

Cytophagaceae↗
PubMed1979

Fatty acid composition of gliding bacteria: oral isolates of Capnocytophaga compared with Sporocytophaga.

The extractable and bound lipids and cellular fatty acids of the gram-negative gliding bacteria, Capnocytophaga sputigena, C. gingivalis, and C. ochracea were compared to the non-host-related gliding bacterium Sporocytophaga myxococcoides. The extractable lipids represented between 17 and 28% of the cell dry weight, whereas only 2 to 4% of the lipids were in the bound fraction. The methyl esters of the cellular fatty acids were mainly aC15:0, which accounted for 69 to 73% of the total extractable fatty acids; S. myxococcoides had a similar distribution of branched-chain fatty acids; however, aC17:0 was the predominant fatty acid in this free-living gliding organism.

Cytophagaceae↗
PubMed1979

Surface ultrastructure of some oral bacteria.

Adhesion of Streptococcus sanguis, Fusobacterium nucleatum and an Actinomyces sp. to enamel and epon and their interspecies cohesion was studied with scanning and transmission electron microscopy. For adhesion studies enamel or epon was coated with salivary macromolecules and then cells of S. sanguis and in some experiments also with F. nucleatum or Actinomyces sp. Cells of S. sanguis were seen scattered over the surface of a thin "pellicle" that was heavily stained, and F. nucleatum and Actinomyces sp. adhered to S. sanguis or directly to the "pellicle". For studies of cohesion S. sanguis was brought to cohere with F. nucleatum or Actinomyces sp. and then processed for transmission electron microscopy. The morphology of the cell surface structures involved was studied in negatively stained preparations or in thin sections of material treated with ruthenium red or poststained with uranyl and lead salts, phosphotungstic acid or periodic acid-thiocarbohydrazide-osmium tetroxide. S. sanguis demonstrated a fuzzy coat of fimbriae that seemed to unfold in areas of contact with other cells, while cells of F. nucleatum had 6-10 polar pilus-like fimbriae, which appeared to be instrumental in cohesion, as did a dense coat of long, slender fimbriae that covered cells of Actinomyces sp.

Actinomyces↗