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Infection and Immunity Feb 1977A levansucrase was demonstrated in the growth medium and in association with the cell surface of Actinomyces viscosus. The amount of enzyme produced relative to cell...
A levansucrase was demonstrated in the growth medium and in association with the cell surface of Actinomyces viscosus. The amount of enzyme produced relative to cell density is not significantly affected by the growth conditions. Sugar alcohols inhibit growth of the cells. The levansucrase hydrolyzes sucrose to produce free glucose and levan; some free fructose is also formed. There is no requirement for cofactors. The Km for sucrose is 12 mM. A variety of heavy metal ions and two disaccharides, lactose and cellobiose, inhibit the enzyme. The levansucrase was purified to homogeneity and has a specific activity of 90 micronmol of glucose release per min per mg. The enzyme has a molecular weight of 220,000 and is composed of subunits of molecular weight 80,000. The levan product contains both beta(2 leads to 1) and beta(2 leads to 6) linkages. The enzyme remains tightly bound to the levan product, resulting in the formation of high-molecular-weight polymer on the order of 10(8) daltons. The possible role of the levan and levansucrase of A. viscosus in the pathogenesis of periodontal disease is discussed.
Topics: Actinomyces; Concanavalin A; Disaccharides; Fructose; Glucose; Hexosyltransferases; Hydrogen-Ion Concentration; Kinetics; Metals; Molecular Conformation; Molecular Weight; Myeloma Proteins; Polysaccharides, Bacterial; Sucrose; Temperature; Tromethamine
PubMed: 14893
DOI: 10.1128/iai.15.2.518-526.1977 -
Oral Microbiology and Immunology Aug 1994The sorbitol fermentation by Actinomyces viscosus and Actinomyces naeslundii was studied with washed sorbitol-grown cells. The fermentation was followed by titration of... (Comparative Study)
Comparative Study
The sorbitol fermentation by Actinomyces viscosus and Actinomyces naeslundii was studied with washed sorbitol-grown cells. The fermentation was followed by titration of acids produced at pH 7.0 under anaerobic conditions. Metabolic end-products and intracellular levels of NAD, NADH and glycolytic intermediates during the fermentation were also analyzed. Cell extracts were examined for certain enzyme activities. Bicarbonate was required for acid production from sorbitol and from a mixture of glucose and sorbitol. Malate and fumarate could also support the acid production of A. viscosus. The main end-products were succinate and lactate but not ethanol. Cell extracts showed no activities of alcohol and aldehyde dehydrogenases, but they had activities of malate dehydrogenase and fumarate reductase. In the absence of bicarbonate, malate or fumarate, the intracellular NADH/NAD ratio increased and the levels of 3- and 2-phosphoglycerate and phosphoenolpyruvate decreased. The results indicate that oral sorbitol-fermenting actinomyces lack the ethanol pathway that can contribute to NADH oxidation. To maintain intracellular redox balance during anaerobic sorbitol fermentation, these bacteria can oxidize surplus NADH through a succinate pathway.
Topics: Actinomyces; Actinomyces viscosus; Dental Plaque; Fermentation; Fumarates; Glucose; Glycolysis; Humans; Lactates; Maleates; NAD; Sodium Bicarbonate; Sorbitol; Succinates
PubMed: 7478761
DOI: 10.1111/j.1399-302x.1994.tb00061.x -
The American Journal of Pathology Mar 1983The histopathologic features of experimental actinomycotic lesions produced in mice by Actinomyces israelii, Actinomyces naeslundii, and Actinomyces viscosus were... (Comparative Study)
Comparative Study
The histopathologic features of experimental actinomycotic lesions produced in mice by Actinomyces israelii, Actinomyces naeslundii, and Actinomyces viscosus were examined. In lesions caused by A israelii the outer edge of the bacterial granule exhibited an eosinophilic fringe with no evidence of penetration of polymorphonuclear leukocytes (PMNs) into the bacterial granule. Chronic lesions after 6 weeks contained lobulated advancing fronts as well as areas of resolution showing heavy penetration by phagocytic cells. The number of macrophages and plasma cells in these lesions increased with time. In contrast, lesions caused by A viscosus and A naeslundii showed cellular evidence of resolution during the early stages of the infection (3-6 weeks). The bacterial core was readily penetrated and fragmented by PMNs in early A viscosus lesions. In lesions caused by A naeslundii there was less penetration of the central core by PMNs, and the bacterial granule tended to retain its structural integrity. Elongated crystals of hyaloid material appeared in lesions caused by all species. These protein-rich bodies appeared to be associated with resolving areas of the lesions. The observed contrast in the histopathologic appearance of actinomycotic lesions caused by A israelii, A naeslundii, and A viscosus is suggestive of important differences in the immune response of the host to infections caused by these three species.
Topics: Actinomyces; Actinomycosis; Animals; Granulocytes; Male; Mice; Species Specificity
PubMed: 6829706
DOI: No ID Found -
Infection and Immunity Jan 1981Human strains of Actinomyces viscosus and A. naeslundii differ in the time of their appearance and in their patterns of colonization in the mouth. Strains of these... (Comparative Study)
Comparative Study
Human strains of Actinomyces viscosus and A. naeslundii differ in the time of their appearance and in their patterns of colonization in the mouth. Strains of these organisms were found to differ in their abilities to adsorb to saliva-treated hydroxyapatite (S-HA) surfaces, thought to mimic the teeth, and these differences parallel their patterns of colonizing the dentition. Thus, strains of A. viscosus tended to adsorb in higher numbers to hydroxyapatite (HA) treated with saliva of older children and adults than with saliva of younger children (ages 6 to 11). These salivary changes may account for the increased frequency with which this organism can be isolated from the mouths of children as they grow older. In contrast, strains of A. naeslundii and Streptococcus mutans did not show a preference for attaching to either type of S-HA. Strains of A. viscosus also generally adsorbed in higher numbers than A. naeslundii to HA treated with adult saliva; this may explain why higher proportions of A. viscosus are usually recoverable from the teeth of adults, even though A. naeslundii is generally present in higher proportions in saliva. Significant variation was noted between strains and between saliva samples collected from different donors. The differences in adsorptive behavior of strains of these species suggests that they are binding to different receptors in the salivary glycoprotein coating on HA surfaces. Adsorption of A. naeslundii ATCC 12104 was enhanced when S-HA was pretreated with neuraminidase, but this had little effect upon the adsorption of other Actinomyces strains tested. Adsorption of strain ATCC 12104 to S-HA was also strongly inhibited by fructose and sucrose and weakly inhibited by glucose, maltose, galactose, and lactose. However, other strains of A. naeslundii tested were affected less, or not at all, by these sugars. Adsorption of two strains of A. viscosus was not affected by any of the sugars or amines tested.
Topics: Actinomyces; Adsorption; Adult; Amines; Carbohydrates; Child; Humans; Hydroxyapatites; Neuraminidase; Saliva; Species Specificity
PubMed: 7216448
DOI: 10.1128/iai.31.1.261-266.1981 -
Oral Microbiology and Immunology Feb 1991Treatment of hydroxyapatite (HA) with human type I or type III collagen strongly promoted adhesion of Actinomyces viscosus LY7 cells. Treatment with human type V...
Treatment of hydroxyapatite (HA) with human type I or type III collagen strongly promoted adhesion of Actinomyces viscosus LY7 cells. Treatment with human type V collagen was somewhat less effective while treatment with human type IV or rat type I collagen was significantly less effective. Electron microscopic observations revealed that A. viscosus cells also attached to fibrils prepared from human type I collagen. The alpha 1 (1) polypeptide chain derived from type I collagen was ineffective in promoting binding and the alpha 2 (1) polypeptide chain exhibited moderate activity. Heat- or urea-denatured type I collagens were also ineffective in promoting binding. Mutants of A. viscosus that possess type 1 fimbriae, but not type 2 fimbriae or no fimbriae, also bound to collagen-treated HA; this suggests that the adhesin responsible was associated with type 1 fimbriae. Strains of Actinomyces israelii and Actinomyces odontolyticus also exhibited strong binding to collagen-treated HA, while Actinomyces naeslundii ATCC 12104 did not. The avidity of Actinomyces species for collagen would seem to be at least partially responsible for the high proportions of these organisms found on cemental and root tooth surfaces.
Topics: Actinomyces viscosus; Bacterial Adhesion; Bacterial Proteins; Collagen; Dental Plaque; Fimbriae, Bacterial; Humans; Hydroxyapatites; Salivary Proteins and Peptides
PubMed: 1682868
DOI: 10.1111/j.1399-302x.1991.tb00443.x -
Journal of Dental Research Apr 1978
Topics: Actinomyces; Adult; Dental Plaque; Humans; Saliva; Tooth
PubMed: 280567
DOI: 10.1177/00220345780570040201 -
Oral Microbiology and Immunology Dec 1994The initial steps of sorbitol catabolism were studied in 4 strains of Actinomyces naeslundii and Actinomyces viscosus that had been isolated from human dental plaque....
The initial steps of sorbitol catabolism were studied in 4 strains of Actinomyces naeslundii and Actinomyces viscosus that had been isolated from human dental plaque. Cell-free extracts were prepared from cells grown in the presence of either sorbitol, xylitol or glucose. The extracts from all strains grown on sorbitol had nicotinamide adenine dinucleotide-linked dehydrogenase activities for sorbitol and xylitol and reduced nicotinamide adenine dinucleotide-linked reductase activities for fructose and xylulose. Two of the strains also exhibited these activities when grown in the presence of xylitol, and all glucose-grown cells lacked them. The results indicate that sorbitol metabolism in oral actinomyces involve oxidation of sorbitol to fructose by an inducible enzyme, nicotinamide adenine dinucleotide-linked sorbitol dehydrogenase. This step is followed by the phosphorylation of fructose with guanosine triphosphate as a main phosphoryl donor. Thus, the initial catabolic pathway of sorbitol in A. naeslundii and A. viscosus is different from those described for other oral bacteria.
Topics: Actinomyces; Actinomyces viscosus; Enzyme Induction; Fructosephosphates; Hexokinase; L-Iditol 2-Dehydrogenase; NAD; NADH, NADPH Oxidoreductases; Oxidoreductases; Sorbitol
PubMed: 7870473
DOI: 10.1111/j.1399-302x.1994.tb00288.x -
Infection and Immunity Feb 1982Germfree Osborne-Mendel rats were monoassociated with Actinomyces viscosus or Streptococcus mutans. The adherence and subsequent growth of these organisms on the tooth... (Comparative Study)
Comparative Study
Germfree Osborne-Mendel rats were monoassociated with Actinomyces viscosus or Streptococcus mutans. The adherence and subsequent growth of these organisms on the tooth surface was studied by means of total viable cell counts. Both A. viscosus and S. mutans showed a lag phase and an exponential growth phase, similar to logarithmic growth in batch cultures. The exponential growth rates of S. mutans and A. viscosus were 0.63 h-1 (doubling time [td] = 1.1 h) and 0.24 h-1 (td = 2.9 h), respectively. After a period of rapid growth, the rate declined and the populations approached a steady state. The presence of a sucrose-containing diet did not significantly influence the exponential growth rates of A. viscosus and S. mutans, but had a slight negative effect on the initial adherence of S. mutans at the tooth surface.
Topics: Actinomyces; Adhesiveness; Animals; Diet, Cariogenic; Germ-Free Life; Kinetics; Rats; Starvation; Streptococcus mutans; Tooth
PubMed: 7056576
DOI: 10.1128/iai.35.2.583-587.1982 -
Infection and Immunity Nov 1979Human A, B, and O erythrocytes (RBC) were agglutinated by many human strains of Actinomyces viscosus and A. naeslundii. At 37 degrees C, these bacterium-mediated...
Human A, B, and O erythrocytes (RBC) were agglutinated by many human strains of Actinomyces viscosus and A. naeslundii. At 37 degrees C, these bacterium-mediated hemagglutination reactions required the action of bacterial neuraminidase upon the RBC; however, at 4 degrees C, the requirement for neuraminidase was not as striking. Bacterial cell suspensions which caused hemagglutination at 37 degrees C contained both soluble extracellular and cell-associated neuraminidase activities as shown by enzyme assays using a soluble substrate (i.e., alpha 1-acid glycoprotein). Bacterium-mediated hemagglutination occurred only in the presence of soluble neuraminidase activity, and the rate of hemagglutination could be inhibited by 2-deoxy-2,3-dehydro-N-acetylneuraminic acid, a competitive inhibitor of purified soluble neuraminidase from A. viscosus T14V. Suspensions of bacteria which contained only cell-associated neuraminidase activity were unable to initiate hemagglutination, but they caused immediate hemagglutination when mixed with neuraminidase-treated RBC. All hemagglutination reactions were reversible in the presence of 0.02 M lactose and were abolished by heating (85 degrees C for 30 min) the actinomycete cells but not the RBC. The proposed mechanism of hemagglutination involves two sequential steps: (i) the action of neuraminidase to unmask galactose-containing receptors on the RBC and (ii) the multivalent binding of these receptors by many low-affinity lection sites on the bacterial surface.
Topics: Actinomyces; Chemical Phenomena; Chemistry; Clostridium perfringens; Cold Temperature; Dental Plaque; Erythrocytes; Glycoproteins; Hemagglutination; Humans; Neuraminidase; Sialic Acids; Solubility; Species Specificity
PubMed: 232691
DOI: 10.1128/iai.26.2.563-572.1979 -
American Journal of Veterinary Research Jul 1972
Topics: Actinomyces; Actinomycosis; Animals; Dog Diseases; Dogs; Female; Fluorescent Antibody Technique; Goats; Male; Swine; Swine Diseases
PubMed: 4557020
DOI: No ID Found