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Infection and Immunity Sep 2001The ability of Actinomyces naeslundii to convert sucrose to extracellular homopolymers of fructose and to catabolize these types of polymers is suspected to be a...
The ability of Actinomyces naeslundii to convert sucrose to extracellular homopolymers of fructose and to catabolize these types of polymers is suspected to be a virulence trait that contributes to the initiation and progression of dental caries and periodontal diseases. Previously, we reported on the isolation and characterization of the gene, ftf, encoding the fructosyltransferase (FTF) of A. naeslundii WVU45. Allelic exchange mutagenesis was used to inactivate ftf, revealing that FTF-deficient stains were completely devoid of the capacity to produce levan-type (beta2,6-linked) polysaccharides. A polyclonal antibody was raised to a histidine-tagged, purified A. naeslundii FTF, and the antibody was used to localize the enzyme in the supernatant fluid. A sensitive technique was developed to detect levan formation by proteins that had been separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the method was used to confirm that the levan-synthesizing activity of A. naeslundii existed predominantly in a cell-free form, that a small amount of the activity was cell associated, and that the ftf mutant was unable to produce levans. By using the nucleotide sequence of the levanase gene of a genospecies 2 A. naeslundii, formerly Actinomyces viscosus, a portion of a homologue of this gene (levJ) was amplified by PCR and inserted into a suicide vector, and the resulting construct was used to inactivate the levJ gene in the genospecies 1 strain WVU45. A variety of physiologic and biochemical studies were performed on the wild-type and LevJ-deficient strains to demonstrate that (i) this enzyme was the dominant levanase and sucrase of A. naeslundii; (ii) that LevJ was inducible by growth in sucrose; (iii) that the LevJ activity was found predominantly (>90%) in a cell-associated form; and (iv) that there was a second, fructose-inducible fructan hydrolase activity produced by these strains. The data provide the first detailed molecular analysis of fructan production and catabolism in this abundant and important oral bacterium.
Topics: Actinomyces; Bacterial Proteins; Culture Media; Electrophoresis, Polyacrylamide Gel; Fructans; Gene Expression Regulation, Bacterial; Glycoside Hydrolases; Hexosyltransferases; Humans; Sucrase; Sucrose
PubMed: 11500409
DOI: 10.1128/IAI.69.9.5395-5402.2001 -
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 -
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 -
The Journal of Biological Chemistry Jul 1990Actinomyces naeslundii (ATCC 12104) and Actinomyces viscosus (ATCC 19246) were radiolabeled externally (125I) or metabolically (35S) and analyzed for their ability to... (Comparative Study)
Comparative Study
Actinomyces naeslundii (ATCC 12104) and Actinomyces viscosus (ATCC 19246) were radiolabeled externally (125I) or metabolically (35S) and analyzed for their ability to bind glycosphingolipids separated on thin layer chromatograms or coated in microtiter wells. Two binding properties were found and characterized in detail. (i) Both bacteria showed binding to lactosylceramide (LacCer) in a fashion similar to bacteria characterized earlier. The activity of free LacCer was dependent on the ceramide structure; species with 2-hydroxy fatty acid and/or a trihydroxy base were positive, while species with nonhydroxy fatty acid and a dihydroxy base were negative binders. Several glycolipids with internal lactose were active but only gangliotriaosylceramide and gangliotetraosylceramide were as active as free LacCer. The binding to these three species was half-maximal at about 200 ng of glycolipid and was not blocked by preincubation of bacteria with free lactose or lactose-bovine serum albumin. (ii) A. naeslundii, unlike A. viscosus, showed a superimposed binding concluded to be to terminal or internal GalNAc beta and equivalent to a lactose-inhibitable specificity previously analyzed by other workers. Terminal Gal beta was not recognized in several glycolipids, although free Gal and lactose were active as soluble inhibitors. The binding was half-maximal at about 10 ng of glycolipid. A glycolipid mixture prepared from a scraping of human buccal epithelium contained an active glycolipid with sites for both binding specificities.
Topics: Actinomyces; Antigens, CD; Bacterial Adhesion; Carbohydrate Sequence; Chromatography, Thin Layer; Epithelium; Erythrocytes; Fatty Acids; Gangliosides; Glycosphingolipids; Humans; Hydroxylation; Iodine Radioisotopes; Lactosylceramides; Molecular Sequence Data; Mouth; Structure-Activity Relationship; Sulfur Radioisotopes
PubMed: 2358461
DOI: No ID Found -
Infection and Immunity Feb 1988Actinomyces viscosus LY7 cells adsorbed in high numbers to experimental pellicles formed on hydroxyapatite (HA) from human parotid or submandibular saliva but not to...
Actinomyces viscosus LY7 cells adsorbed in high numbers to experimental pellicles formed on hydroxyapatite (HA) from human parotid or submandibular saliva but not to pellicles prepared from human plasma or serum. To determine the nature of the salivary components responsible for promoting adhesion, pellicles were prepared from fractions of submandibular and parotid saliva obtained by chromatography on Trisacryl GF 2000 columns. Adsorption of LY7 cells was promoted by two groups of fractions. Each group was rechromatographed on DEAE-agarose. Fractions which promoted adsorption of LY7 cells were found by polyacrylamide gel electrophoresis to contain the acidic proline-rich proteins (PRPs) and statherin. Pellicles prepared from 12-micrograms/ml solutions of pure PRP-1, PRP-2, or parotid isoelectric focusing (PIF-slow) variant promoted maximal adsorption of A. viscosus LY7 cells. Somewhat higher concentrations of PRP-3 and PRP-4 were required for maximal adsorption, indicating that the 44-residue carboxy-terminal segment of PRP-1, PRP-2, and PIF-slow enhances LY7 binding but is not essential. Much higher concentrations of statherin were required to promote LY7 adsorption. Adsorption of LY7 cells to pellicles prepared from PRP-1 was not affected over the range of pH 5 to 8. Adsorption was also not inhibited by 50 mM lactose, which is consistent with the notion that type 1 fimbriae, rather than type 2 fimbriae, were responsible. A. viscosus T14, Actinomyces odontolyticus ATCC 17982, and Actinomyces israelii 12597 also adsorbed to PRP-1 pellicles, whereas Actinomyces naeslundii ATCC 12104 did not. Although A. viscosus cells bind strongly to adsorbed PRP-1, the presence of PRP-1 or PRP-3 in solution did not inhibit adhesion. Similarly, [3H]PRP-1 did not bind to LY7 cells, nor was it degraded when incubated with the organism. However, LY7 cells adsorbed to [3H]PRP-1 pellicles. These data suggest that hidden molecular segments of PRP become exposed when the protein adsorbs to HA; these segments then react with adhesins of LY7 cells. The apparent ability of A. viscosus cells to recognize segments of PRPs which are exposed only in surface-adsorbed molecules provides a novel mechanism which enables the organism to attach to teeth when suspended in salivary secretions.
Topics: Actinomyces; Adsorption; Bacterial Adhesion; Dental Plaque; Fimbriae, Bacterial; Hydroxyapatites; Peptide Fragments; Salivary Proteins and Peptides
PubMed: 2892794
DOI: 10.1128/iai.56.2.439-445.1988 -
Metabolites Apr 2024The oral cavity contains a vast array of microbes that contribute to the balance between oral health and disease. In addition, oral bacteria can gain access to the...
The oral cavity contains a vast array of microbes that contribute to the balance between oral health and disease. In addition, oral bacteria can gain access to the circulation and contribute to other diseases and chronic conditions. There are a limited number of publications available regarding the comparative lipidomics of oral bacteria and fungi involved in the construction of oral biofilms, hence our decision to study the lipidomics of representative oral bacteria and a fungus. We performed high-resolution mass spectrometric analyses (<2.0 ppm mass error) of the lipidomes from five Gram-positive commensal bacteria: , , , , and ; five Gram-positive opportunistic bacteria: , , , , and ; seven Gram-negative opportunistic bacteria: , , , , , and ; and one fungus: . Our mass spectrometric analytical platform allowed for a detailed evaluation of the many structural modifications made by microbes for the three major lipid scaffolds: glycerol, sphingosine and fatty acyls of hydroxy fatty acids (FAHFAs).
PubMed: 38668368
DOI: 10.3390/metabo14040240 -
Indian Journal of Dental Research :... 2016This study evaluates the antimicrobial efficacy of commercially available chlorhexidine (CHX) mouthrinses of different concentrations. (Comparative Study)
Comparative Study
CONTEXT
This study evaluates the antimicrobial efficacy of commercially available chlorhexidine (CHX) mouthrinses of different concentrations.
AIMS
To evaluate and compare the antimicrobial efficacy of commercially available CHX mouthrinses of different concentrations (0.2%, 0.12%, and 0.1%) against specific standard strains of oral microflora at full strength (FS) and 1:1 dilution at 24 h.
SETTINGS AND DESIGN
Ten commercially available 0.2% (Rexidine, Hexidine, Smilehex, Chlorhex, Hexidale, Hex, Everfresh, and Gargwell), 0.12% (Periogard), and 0.1% (Eludril) CHX mouthrinses were selected to evaluate the efficacy against specific oral microflora using agar well diffusion Method.
MATERIALS AND METHODS
The standard strains of Streptococcus mutans American Type Culture Collection (ATCC 21293), Streptococcus sanguis Microbial Type Culture Collection (MTCC 442), Actinomyces viscosus (ATCC 3268), Staphylococcus aureus (ATCC 25923), Streptococcus pyogenes (MTCC 442), and Candida albicans (MTCC 183) were selected. The antimicrobial efficacy was calculated by measuring mean inhibitory zones formed on agar media.
STATISTICAL ANALYSIS USED
Independent t-test, one-way ANOVA, Kruskal-Wallis tests, and Tukey's Post hoc analysis were used.
RESULTS
Among 0.2% of CHX mouthrinses at FS and 1:1 dilution, hexidine was effective against most of the microorganisms except with S. pyogenes and C. albicans, where Hex and Hexidale were effective, respectively. When the concentration of 0.1% and 0.12% CHX was considered, Eludril was more effective at FS against all except with S. aureus and S. pyogenes which were more sensitive to Periogard at both FS and 1:1 dilution.
CONCLUSIONS
0.12% and 0.1% of CHX mouthrinses showed comparable efficacy with 0.2% CHX mouthrinses irrespective of their formulations.
Topics: Actinomyces; Anti-Infective Agents, Local; Candida albicans; Chlorhexidine; Microbial Sensitivity Tests; Mouthwashes; Staphylococcus
PubMed: 27054861
DOI: 10.4103/0970-9290.179816 -
Biomedicines Jun 2020Dental caries is considered to be a preventable disease, and various antimicrobial agents have been developed for the prevention of dental disease. However, many...
BACKGROUND
Dental caries is considered to be a preventable disease, and various antimicrobial agents have been developed for the prevention of dental disease. However, many bacteria show resistance to existing agents.
METHODS/PRINCIPAL FINDINGS
In this study, four known 1,4-naphthoquinones and newly synthesized 10 pyrimidinone-fused 1,4-naphthoquinones, i.e. KHQ 701, 702, 711, 712, 713, 714, 715, 716, 717 and 718, were evaluated for antimicrobial activity against and Pyrimidinone-fused 1,4-naphthoquinones were synthesized in good yields through a series of chemical reactions from a commercially available 1,4-dihydroxynaphthoic acid. MIC values of KHQ 711, 712, 713, 714, 715, 716, 717 and 718 were 6.25-50 μg/mL against (CCARM 5511) 6.25-25 μg/mL against (KACC11954) and (CCARM 3506), 1.56-25 μg/mL against (KACC 13234), 3.125-100 μg/mL against (KACC16833), 1.56-100 μg/mL against (KCTC5809) and (KCTC 5352), 3.125-50 μg/mL against (KCTC 9146) and 3.125-12.5 μg/mL against (KCTC 2640) with a broth microdilution assay. A disk diffusion assay with KHQ derivatives also exhibited strong susceptibility with inhibition zones of 0.96 to 1.2 cm in size against . Among the 10 compounds evaluated, KHQ 711, 712, 713, 715, 716 and 717 demonstrated strong antimicrobial activities against the 9 types of pathogenic oral bacteria. A pyrimidin-4-one moiety comprising a phenyl group at the C2 position and a benzyl group at the N3 position appears to be essential for physiological activity.
CONCLUSION/SIGNIFICANCE
Pyrimidinone-fused 1,4-naphthoquinones synthesized from simple starting compounds and four known 1,4-naphthoquinones were synthesized and showed strong antibacterial activity to the 9 common oral bacteria. These results suggest that these derivatives should be prospective for the treatment of dental diseases caused by oral bacteria, including drug-resistant strains.
PubMed: 32549271
DOI: 10.3390/biomedicines8060160 -
Infection and Immunity Dec 1982Glucose uptake was examined by using whole-cell suspensions of Streptococcus mutans (strains BHT, Ingbritt, and GS-5), Streptococcus mitis (strains 9811 and 72x41), and... (Comparative Study)
Comparative Study
Glucose uptake was examined by using whole-cell suspensions of Streptococcus mutans (strains BHT, Ingbritt, and GS-5), Streptococcus mitis (strains 9811 and 72x41), and Actinomyces viscosus (strains T6 and WVU626) incubated for up to 90 min in 0 to 82% (vol/vol) human whole salivary supernatant. Glucose uptake by the S. mutans strains was completely inhibited at all saliva concentrations. Dithiothreitol (DTT), present during saliva incubation, prevented saliva inhibition. Glucose uptake was also restored when saliva-inhibited cells were subsequently exposed to DTT. The inclusion of catalase in the saliva incubation mixtures resulted in protection equal to that obtained with DTT. The S. mitis strains were also inhibited by saliva but to a far lesser extent that S. mutans. DTT and catalase also protected S. mitis from saliva inhibition. Both A. viscosus strains were completely refractory to saliva inhibition of glucose uptake. Based on (i) the sensitivity of the catalase-negative streptococci and the resistance of catalase-positive actinomyces to saliva inhibition and (ii) the equal and complete protection to saliva inhibition afforded by DTT and catalase, we conclude that the lactoperoxidase-SCN(-)-H(2)O(2) system in saliva was the only antibacterial system expressed under our experimental conditions. The relative resistance of S. mitis 9811 (compared with S. mutans BHT) to saliva inhibition was shown not to result from poor H(2)O(2) production in either glucose-supplemented buffer or saliva solutions. S. mitis produced inhibitory quantities of H(2)O(2) that equaled or exceeded S. mutans H(2)O(2) accumulation. It is suggested that S. mitis might possess a greater ability to repair lactoperoxidase-mediated damage than does S. mutans. Every organism studied exhibited a saliva concentration-dependent, cell growth-independent stimulation of glucose uptake after 60 to 90 min of incubation. The A. viscosus and S. mitis strains showed saliva stimulation (or stabilization) of glucose uptake with unsupplemented saliva. In the case of S. mutans, saliva stimulation was only observed when DTT was present. The possible role of salivary lactoperoxidase as a modulator of the intraoral site specificities exhibited by S. mutans is discussed.
Topics: Actinomyces; Biological Transport; Catalase; Dithiothreitol; Glucose; Humans; Hydrogen Peroxide; Kinetics; Saliva; Streptococcus; Streptococcus mutans
PubMed: 7152663
DOI: 10.1128/iai.38.3.1060-1067.1982 -
Infection and Immunity Dec 1978The morphology and serology of Actinomyces viscosus T14V and T14AV were compared. When grown in supplemented tryptic soy broth, the virulent strain (T14V) possessed an... (Comparative Study)
Comparative Study
The morphology and serology of Actinomyces viscosus T14V and T14AV were compared. When grown in supplemented tryptic soy broth, the virulent strain (T14V) possessed an extensive network of cell surface fibrils. In this medium, the avirulent strain (T14AV) possessed a microcapsule, absent on strain T14V, and a comparatively small number of surface fibrils. Mild acid extraction (Lancefield procedure) solubilized common antigenic components on both strains as well as components detectable only in the virulent strain T14V (virulence-associated antigens 1 and 2). When grown in Socransky chemically defined medium or Carlsson complex medium, the avirulent strain possessed increased amounts of surface fibrils and virulence-associated antigens. Whole cells and extracts of avirulent cells grown in Socransky medium absorbed antibodies to virulence-associated antigens with approximately the same efficiency as did whole cells and extracts of strain T14V, suggesting antigenic similarity between the two cell types. The results strongly support the hypothesis that observable differences between A. viscosus strains T14V and T14AV represent quantitative, rather than qualitative, differences in particular cell surface components. In addition, the magnitude of these differences can be modified by changing growth conditions.
Topics: Actinomyces; Antigens, Bacterial; Cell Membrane; Culture Media; Species Specificity
PubMed: 730385
DOI: 10.1128/iai.22.3.934-944.1978