bluuebunny/crossref_metadata_2025 huggingface dataset:
Human strains of mutans streptococci show different cariogenic potential in the hamster model
Authors: Köhler Birgitta , Krasse Bo
Published: December 2007

The cariogenic potential of fresh humans strains of Streptococcus mutans and Streptococcus sobrinus was examined in hamsters maintained on a high sucrose d'et. The strains IB 16 (S. mutans) and B13 (S. sobrinus) isolated 20–25 yrs ago served as positive controls. Three series of experiments were run. Some strains Were tested once and some strains were tested in all 3 experiments. The animals infected with S. sobrinus strains generally showed lower caries scores than those‘nfected with S. mutans strains. Among the groups infected with the different strains of S. mutans the caries scores varied. In one of the experiments the caries score of the animals infected with one of the Icelandic S. mutans strains was significantly higher than that of the positive control group and the group infected W|th one of the fresh Swedish isolates. Thus, different strains of mutans streptococci where shown to induce varying caries activity in the hamster model.
Ingestion of Bacteroides buccae, Bacteroides oris, Porphyromonas gingivalis, and Fusobacterium nucleatum by human polymorphonuclear leukocytes in vitro
Authors: Kerosuo Eero , Haapasalo Markus , Alli Kristiina , Lounatmaa Kari
Published: December 2007

The phagocytic ingestion of clinical isolates and reference strains of Bacteroides buccae, Bacteroides oris, Porphyromonas gingivalis and Fusobacterium nucleatum by polymorphonuclear leukocytes (PMNs) was studied. Special attention was focused on the hydrophobicity of the strains. B. buccae strains, less or equally hydrophobic than PMNs, were poorly ingested without opsonization. Hydro‐phobic, but not hydrophilic, strains of B. oris and both hydrophilic and hydro‐phobic P. gingival's and F. nucleatum strains were readily ingested without opsonization. Hydrophobicity thus contributes to the adherence of bacteria to PMNs in some, but not all, species tested. Normal human serum enhanced the ingestion of B. buccae, but failed to do so after heat‐inactivation. Heat‐inactivation of the immune serum to B. buccae strain ES57 did not reduce opsonic activity suggesting that specific antibodies enhanced the ingestion of B. buccae.
Leukocidal activity of staphylococci isolated from human periodontal lesions
Authors: Iwase Masayasu , Slots Jørgen , Berthold Peter , Taichman Norton S.
Published: December 2007

Staphylococci isolated from subgingival samples of patients with advanced periodontitis were tested for leukocidal activity. Intact organisms, bacterial sonicates or bacterial culture supernatants were incubated with human neutrophils that had been prelabeled with 51chromium. The majority of Staphylococcus aureus periodontal isolates provoked dose–dependent extracellular release of the radiolabel. by contrast, other strains of staphylococci had marginal or no demonstrable lukocidal activity. Leukocidal activity was heat‐sensitive and was neutralized by horse anti‐leukocidin antibodies. The results indicate that 5. aureus colonizing human periodontal lesions elaborate a leukocidin that may conceivably destroy neutrophils that emigrate into the gingival region. This could adversely affect the overall status of this antimicrobial defense system in the gingival area and contribute to the pathogenicity of S. aureus as well as other potential periodontopathic organisms.
The hemagglutinating adhesin HA‐Ag2 of Bacteroides gingivalis is distinct from fimbrilin
Authors: Mouton Christian , Eidhin Déirdre Ni , Deslauriers Manon , Lamy Lucie
Published: December 2007

We carried out a series of immunoblots with antigenic preparations from the periodontal pathogen Bacteroides gingivalis using antisera of restricted specificity for the hemagglutinating adhesin HA‐Ag2, and for the major structural subunit of the fimbriae (fimbrilin). We have been able to show that these 2 antigens are distinct. The fimbrilin subunit had an apparent molecular weight of 42 kDa in all of the bacterial preparations tested. HA‐Ag2 occurred as a pair of bands at 43 and 49 kDa in outer membranes prepared as extracellular vesicles, and at 33 and 38 kDa in glass‐bead‐EDTA extracted antigens and in sheared‐cell outer membranes prepared in the presence of EDTA. No HA‐Ag2 was found in an enriched fimbrial preparation. The 2 antigens could thus be distinguished on the basis of their behaviour when subjected to different extraction techniques. The lower apparent molecular weight of HA‐Ag2 (a pair of bands at 33 and 38 kDa) was invariably associated with the presence of EDTA in the buffers used to prepare the extracts, and the effect could be partially prevented by adding MgCl2 to the extraction buffer. The difference in apparent molecular weight of HA‐Ag2 in the different extracts can thus be attributed either to an EDTA‐sensitive tertiary conformation of its component polypeptides, or to an EDTA‐sensitive linkage of each of these polypeptides to an unknown component of approximately 10 kDa.
DNA probe detection of Eikenella corrodens, Wolinella recta and Fusobacterium nucleatum in subgingival plaque
Authors: Lippke J. A. , Peros W. J. , Keville M. W. , Savitt E. D. , French C. K.
Published: December 2007

This cross‐sectional study used species‐specific DNA probes to examine subgingival plaque specimens for the presence of Eikenella corrodens, Wolinella recta, and Fusobacterium nucleatum in adults with untreated periodontitis or gingivitis and in healthy controls. W. recta and F. nucleatum were more prevalent in diseased sites from the periodontitis group when compared with the controls (81% vs 22% and 83% vs 20% respectively). E. corrodens was detected in 62% of the control sites and 81% of the periodontitis sites. Because the control sites commonly contained this organism, E. corrodens may not be useful in differentiating between health and disease. In addition, the relationship between the prevalence of W. recta and F. nucleatum and the prevalence of the established periodontal pathogens, Actinobacillus actinomycetemcomitans, Bacteroides intermedius and Bacteroides gingivalis, was examined. Positive detection of W. recta and F. nucleatum correlated closely with the presence of A. actinomycetemcomitans, B. intermedius and B. gingivalis. Therefore, W. recta and F. nucleatum do not appear to be unique indicators of periodontal disease.
Antimicrobial susceptibility of 1042 strains of Streptococcus mutans and Streptococcus sobrinus: comparison from 1985 to 1989
Authors: Liebana J. , Castillo A. , Peis J. , Baca P. , Piedrola G.
Published: December 2007

A total of 1042 strains of Streptococcus mutans and Streptococcus sobrinus isolated between 1985 and 1989 were tested to study the evolution of their sensitivity to penicillin, amoxycillin, amoxycillin/clavulanic acid, cefuroxime, tetracycline, erythromycin, spiramycin, acetyl spiramycin, lincomycin and clindamycin. The strains were taken from stock cultures and isolated from human saliva and dental plaque. The minimal inhibitory concentration (MIC) was determined by an agar dilution method. Except for spiramycin and acetyl spiramycin, all the antibiotics inhibited 100% of the strains with concentrations 2 μg/ml. Microorganisms from both species underwent a slow progressive loss of sensitivity to all the antibiotics over a 5‐year period of study, showing statistically significant results in most cases.
Biological qualities of saliva sterilized by filtration or ethylene oxide treatment
Authors: Kalfas Sotirios , Rundegren Jan
Published: December 2007

Stimulated whole saliva was centrifuged and sterilized either by filtration in the presence or absence of dithiothreitol (DTT) or by ethylene oxide treatment. Filtration was accomplished by 2 different techniques: conventional positive pressure filtration through prefilters and membranes with decreasing pore sizes and tangential flow microporous filtration. The sterile saliva samples were analyzed for enzyme activities of phosphatases, esterases, glucuronidase, and lysozyme. The samples were also tested by polyacrylamide electrophoresis, isoelectric focusing and for IgA concentration. Moreover, the samples were tested for support of bacterial growth of strains from the genera Actinomyces, Laclobacillus, Neisseria, Rothia and Streptococcus after the addition of glucose at a final concentration of 0.5%. The samples treated with ethylene oxide appeared to be more affected by this treatment than samples treated otherwise, as demonstrated by the electrophoretic analyses and analyses of enzyme activities. Ethylene oxide‐treated saliva also was the least favorable saliva sample to support growth of bacteria. The positive pressure technique gave more rapid filtration than the tangential flow technique. DTT treatment of saliva facilitated filtration and, in contrast to ethylene oxide treatment, it affected the qualities of saliva only to a minor extent compared with the original saliva sample.
Candida biotypes in human adult periodontitis
Authors: Rams Thomas E. , Slots Jørgen
Published: December 2007

Fifty‐five Candida isolates from human periodontal pockets were biotyped using the API 20C micromethod kit system. Candida albicans (11 biotypes) constituted 81.8% of all yeast isolates. A single biotype accounted for 57.8% of the subgingival C. albicans strains. The biotype distribution of C. albicans in human periodontal pockets appears to follow a selectivity pattern similar to that of other oral surfaces.
Characteristics of hemolytic and hemagglutinating activities of Treponema denticola
Authors: Grenier Daniel
Published: December 2007

Treponema denticola, a suspected periodontal pathogen, was shown to agglutinate and lyse human red blood cells. Both activities were cell‐associated, heat‐labile, and produced during the exponential growth phase. Hemolytic activity was time‐dependent and required incubation at 37°C; further incubation at 4°C increased the hemolysis. Hemagglutination was reduced in the presence of D‐glucosamine, EDTA or sodium salicylate, whereas hemolytic activity was affected by calcium chloride, magnesium chloride, EDTA or sodium salicylate. These biological activities may favor a higher concentration of hemin‐containing compounds in periodontal sites, and therefore represent additional potential virulence mechanisms.
Carbohydrate antigen of serotype g “Streptococcus milleri”: immunochemical characterization
Authors: Inoue Masakazu , Yakushiji Tsuyoshi , Konagawa Ryosuke
Published: December 2007

Cell wall carbohydrate antigen of the serotype g “Streptococcus milleri” was extracted with cold trichlorpacetic acid from purified cell walls of the type strain K1K. The extracts were then purified by a DEAE‐Sephadex A‐25 column, followed by a Sephadex G‐100 column. The immunoelectrophoresis revealed that the serotype g carbohydrate antigen preparation displayed a single precipitin band against the crude anti‐K1K serum. The purified type g antigen consisted of rhamnose, galactose, glucose and galactosamine in a ratio of 1.3:3.8:1.0:2.5. The quantitative precipitin inhibition test with various haptens indicated that galactosamine is a major immunodeterminant of the type g‐specific antigen.
Salivary IgA responses to Porphyromonas gingivalis in the cynomolgus monkey. I. Total IgA and IgA antibody levels to P. gingivalis
Authors: Blanchard Steven B. , Cox Sarah E. , Ebersole Jeffrey L.
Published: December 2007

Porphyromonas gingivalis has been associated with the subgingival plaque of advancing disease lesions in various types of periodontitis. Additionally, this species of oral microorganism has been found to increase dramatically in ligature‐induced periodontitis in nonhuman primates (Macaca fascicularis) and has recently been shown to induce progressing disease when implanted into the subgingival plaque in this animal model. Although systemic antibody responses have been demonstrated to P. gingivalis in both human and nonhuman primate with periodontitis, no information is available on the oral secretory IgA antibody response to this bacteria. This report describes the methods for reproducible collection of salivary secretions from cynomolgus monkeys and the development of methods for analyzing salivary IgA levels and specific IgA antibody in the saliva reactive with P. gingivalis. Purification of monkey salivary IgA allowed quantification of IgA using an enzyme‐linked immunosorbent assay (ELISA). Estimation of total IgA levels in saliva showed approximately a 20% greater level of IgA in whole versus parotid saliva from a group of 13 monkeys, with a 2–3 fold variation in levels among this group of animals. Naturally occurring salivary IgA antibody to P. gingivalis, as measured by ELISA, were routinely detectable but low in whole saliva; however, many of the parotid saliva specimens collected exhibited negligible levels of antibody to this microorganism. The IgA antibody in whole saliva showed nearly an 18‐fold variation among the samples from the monkeys. Correlational analyses indicated that, although there was a positive relationship between antibody levels in whole and parotid saliva, the majority of natural IgA antibody in whole saliva appears to be derived from other sources. Additionally, a positive correlation between IgA antibody to P. gingivalis and total IgA levels in parotid saliva indicated a lack of a selective secretory immune response to P. gingivalis in the major salivary glands of normal monkeys. The results of these baseline studies of the nonhuman primate secretory immune responses show that naturally occurring salivary IgA antibody to P. gingivalis is low and the methods developed should facilitate future immunization experiments that can examine the interaction of salivary IgA antibody with the emergence and transmission of P. gingivalis within the oral cavity.
Fc‐binding components: a virulence factor in Actinobacillus actinomycetemcomitans?
Authors: Tolo Kåre , Helgeland Kristen
Published: December 2007

Actinobacillus actinomycetemcomitans (ATCC 33384) can produce and release components that bind to the Fc part of IgG. Fc‐binding components were observed in whole bacteria, capsular material and medium from broth cultures. The components were separated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and immunoblotted with biotinylated Fc‐fragments and myeloma proteins. In a phagocytosis assay with human granulocytes and sheep erythrocytes, pre incubation of opsonized erythrocytes with protein A reduced phagocytosis by 90%. In contrast, preincubation of the opsonizing antibody with medium components from a culture of A. actinomycetemcomitans enhanced the opsonizing effect of the antibody. The enhanced binding of erythrocytes may be caused by formation of aggregates between opsonizing antibody and bacterial Fc‐binding components. Aggregated IgG can bind to low‐affinity Fc gamma II and gamma III receptors that cannot bind monomeric IgG. Release of Fc‐binding components from bacteria may contribute to the periodontal lesion through interference with the phagocytic activity of granulocytes and with the complement system. Fc‐binding components may also interfere with down regulation of the B‐cell response.
Identification of Selenomonas species by whole‐genomic DNA probes, sodium dodecyl sulfate‐polyacrylamide gel electrophoresis, biochemical tests and cellular fatty acid analysis
Authors: Maiden M. F. J. , Tanner A. , Moore W. E. C.
Published: December 2007

Nonisotopic, whole‐genomic DNA probes, sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE), biochemical tests in microtiter trays and cellular fatty acid (CFA) analysis were compared for the identification of 5 oral Selenomonas species. DNA probes were prepared by biotin‐labeling DNA extracted from the type strains of Selenomonas noxia, Selenomonas flueggei, Selenomonas artemidis, Selenomonas infelix and Selenomonas spittigena. The probes were hybridized with DNA from 21 reference strains, 18 fresh isolates of Selenomonas species, and 21 strains of other oral gram‐negative species. Target DNAs were obtained by in situ extraction of colonies blotted onto filter paper. Streptavidin‐linked alkaline phosphatase was used to detect homologous reactions of probe and target DNA. Each Selenomonas species DNA probe reacted with reference strains of only that species. All Selenomonas strains that reacted with the DNA probe for a particular species gave similar biochemical test results, SDS‐PAGE protein profiles, and CFA profiles to those of the type strain of the corresponding species. All the methods tested were useful for identifying the species, and all yielded similar identifications of the fresh isolates. The DNA probes, however, had the potential for identifying Selenomonas species directly from primary isolation plates or plaque samples.
Effect of sampling strategy on the false‐negative rate for detection of selected subgingival species
Authors: Haffajee A. D. , Socransky S. S.
Published: December 2007

Subgingival plaque samples were obtained from the mesial surface of each tooth (maximum 28 samples per subject) in 62 subjects with prior evidence of destructive periodontal disease. The resulting 1596 samples were evaluated for their content of 14 selected taxa using a colony lift method and DNA probes. The present investigation compared the ability of 6 sampling strategies to detect a species known to be present in a subject as determined by the 28‐site sampling procedure. On average, a species was not detected in 68% of the positive subjects if only the upper right first molar was sampled; 55% of subjects if both upper first molars were sampled; 36% of subjects if the 4 first molars were sampled; 28% of subjects if the 6 Ramfjord teeth were sampled; 60% of subjects if the deepest pocket was sampled and 25% of subjects if the 4 deepest pockets were sampled. The error rate was greatest for species that were infrequently detected in plaque samples such as Actinobacillus actinomycetemcomitans scrotype b. This species was not detected in 49% of positive subjects, when the 6 Ramfjord teeth were sampled and 38%) of subjects when the 4 deepest pockets were sampled. The data indicated that multiple plaque samples are needed to minimize false‐negative rates.
Comparative studies of three proteases of Porphyromonas gingivalis
Authors: Fujimura S. , Shibata Y. , Nakamura T.
Published: December 2007

Three thiol‐activated proteases, designated Qa, Ra, and Sa, in the soluble fraction of the cell extract of Porphyromonas gingivalis ATCC 33277 were purified by combinations of gel filtration, ion exchange chromatography and electrophoresis, and characterized. The molecular weights estimated by gel filtration method were 43 kDa (Sa), 87 kDa (Ra), and 170 kDa (Qa). However, they were found to have the same molecular weight (43 kDa), when estimated by SDS‐PAGE, indicating that Sa is a monomeric, Ra is a dimeric and Qa is a tetrameric form. The 3 enzymes showed quite similar biochemical properties, and they could degrade not only the synthetic substrates but immunoglobulins, fibrinogen and albumin.
The establishment of human T cell lines reactive with specific periodontal bacteria
Authors: Ishii T. , Mahanonda R. , Seymour G. J.
Published: December 2007

Human T cell lines (TCLs) were obtained by stimulation of peripheral blood mononuclear cells (PBMCs) with the 2 periodontopathic bacteria, Porphyromonas gingivalis FDC‐381 and Fusobacterium nucleatum FDC‐263. After the first round of stimulation and rest, the cells responded specifically to the bacteria originally used to establish each line. Throughout the culture period, the responsiveness of each of the TCLs to their specific bacteria increased. Phenotypic analysis of the TCLs revealed heterogeneity of cell types. In both TCLs approximately 80% of the cells were T cells, all of which bore the αβ T cell receptor. The P. gingivalis‐reactive TCL (PG‐TCL) showed approximately equal proportions of CD4+ and CD8+ cells, whereas the P. nucleatum‐reactive TCL (FN‐TCL) was predominantly CD4+. The expression of CD25, HLA‐DR, CD45RA and CD29 on these CD4+ cells varied throughout the culture period of 45 days. These results demonstrate that it is possible to establish long‐term T cell lines reacting to specific periodontopathic bacteria.
Laminin binding to Prevotella intermedia
Authors: Kalfas S. , Tigyi Z. , Wikström M. , Naidu A. S.
Published: December 2007

The interaction of laminin (Lm), a basement membrane protein abundant in the periodontium, with 66 strains of Prevotella intermedia isolated from diseased pockets, was tested in a 125I‐labeled protein binding assay. The mean binding value was 28% of the total protein added. The binding significantly increased to 35% when the environmental pH decreased from 7 to 6. The Lm interaction was characterized in a highly binding (about 65%) strain, OMGS105. The binding was rapid and required about 1 min and 1–2 h for 50% and 100%) equilibrium respectively. The 125I‐Lm binding was maximum in the pH interval 3.0 to 6.5 and could not be displaced by unlabeled Lm or inhibited by other proteins and carbohydrates. The interaction was stable in the presence of NaCl or urea (concentrations up to 4 M) but was dissociated by ≥ 1 M KSCN. The Lm‐binding component was thermolabile and sensitive to proteolytic enzymes. Sodium dodecylsulfate‐polyacrylamide gel electrophoresis and Western blot analysis revealed a ∼62 kDa Lm‐binding protein, both in the whole cell extract and the outer membrane preparation. Weaker binding was also observed to other proteins. These data establish the ability of P. intermedia to interact with Lm via certain cell surface proteins, a property that might contribute to the colonization of this bacterium in the periodontal pocket.
Actinobacillus actinomycetemcomitans, Capnocytophaga and Porphyromonas gingivalis in subgingival plaque of adolescents with Down's syndrome
Authors: Barr‐Agholme M. , Dahllöf G. , Linder L. , Modéer T.
Published: December 2007

Levels of Actinobacillus actinomycetemcomitans, Capnocytophaga and Porphyromonas gingivalis were determined in subgingival plaque samples from 37 adolescents with Down's syndrome and 37 healthy controls matched with respect to age and sex. Gingival inflammation, supra‐ and subgingival calculus, periodontal pockets (>4 mm) and alveolar bone loss were registered. Alveolar bone loss was more frequent in Down's syndrome subjects (32%) than in the controls (3%). A. actinomycetemcomitans was detected in the subgingival plaque in 35% of the Down's syndrome adolescents and in 5% of the controls. On site level, A. actinomycetemcomitans and Capnocytophaga were more frequent in the subgingival plaque samples of Down's syndrome children than in those of controls. Comparing Down's syndrome subjects positive or negative for A. actinomycetemcomitans and Capnocytophaga, no significant differences were found in terms of gingival inflammation, periodontal pockets (>4 mm) or number of sites with alveolar bone loss. The results indicate an altered microbial composition of the subgingival plaque of Down's syndrome subjects compared with healthy controls, with higher frequency of A. actinomycetemcomitans.
Experimentally induced infection by oral anaerobic microorganisms in a mouse model
Authors: Baumgartner J. C. , Falkler W. A. , Beckerman T.
Published: December 2007

A mouse model was developed to study the abscessogenic potential of pure and mixed cultures of oral anaerobes associated with infections of endodontic origin. Maximum subcutaneous lesions were seen on their backs between 3 and 14 d after inoculation. Strains of Fusobacterium nucleatum, Peptostreptococcus anaerobius, and Veillonella parvula were pathogenic in pure culture. A mixed culture of F. nucleatum with either Porphyromonas gingivalis or Prevotella intermedia was significantly more pathogenic than F. nucleatum in pure culture. Histopathological examination of tissue sections from control mice injected with India ink in the medium demonstrated a pathway of particulate migration from the backs of the mice to their abdomen.
Glucosyltransferase phase variation in Streptococcus gordonii modifies adhesion to saliva‐coated hydroxyapatite surfaces in a sucrose‐independent manner
Authors: Vickerman M. M. , Clewell D. B. , Jones G. W.
Published: December 2007

Phase variation of Streptococcos gordonii between high (Spp+) and low (Spp−) levels of glucosyltransferase (GTF) activity resulted in the greater adhesion of Spp− strains to saliva‐coated hydroxyapatite (S‐HA) in a washed‐cell adhesion test. Specific GTF mutants did not show this response. Although washed Spp+ cells produced 5‐fold or more glucan from sucrose than Spp− cells did under the conditions of the adhesion test, sucrose elevated the adhesion of both phenotypes to hydroxyapatite (HA) equally, but had no effect on adhesion to S‐HA. This effect was not sucrose‐specific, however, because equimolar amounts of other carbohydrates and NaCl elevated adhesion of both Spp types to levels similar to those seen with sucrose. Adhesion did not correlate with relative changes in cell hydrophobicity. These results suggest that, in addition to changes in GTF activity, other changes relevant to adhesion may occur during Spp phase variation.
Tetracycline inhibition identifies the cellular origin of interstitial collagenases in human periodontal diseases in vivo
Authors: Suomalainen Kimmo , Sorsa Timo , Ingman Tuula , Lindy Otso , Golub Lorne M.
Published: December 2007

Mammalian interstitial collagenases (E.C.3.4.24.7) are considered as key initiators of collagen degradation in periodontal diseases. However, the cellular sources of collagenases present in gingival crevicular fluid have not been completely clarified. Resident fibroblasts and epithelial cells as well as infiltrating neutrophils and monocyte/macrophages are potential sources of the enzymes. We have recently found significant differences in tetracycline inhibition between human neulrophil and fibroblast interstitial collagenases. To address the cellular source of collagenase present in gingival crevicular fluid in 2 distinct periodontal diseases, we studied the tetracycline inhibition of collagenase in gingival crevicular fluid of patients with localized juvenile periodontitis and adult periodontitis. Gingival crevicular fluid samples were collected from deep (<5 mm) periodontal pockets and assayed for collagenase in the presence of 0‐1000 μM doxycycline as well as a chemically modified tetracycline devoid of antimicrobial activity (4‐de‐dimethylaminotelracycline). The drug concentration required to inhibit 50% of collagenase activity (IC50) in localized juvenile periodontitis gingival crevicular fluid was 280 μM for doxycycline and 470 μM for 4‐de‐dimethylaminotetracycline. Significantly lower values, 10–20 μM, were obtained for collagenase in gingival crevicular fluid of patients with adult periodontitis. We propose that systemic letracycline levels are efficient inhibitors of collagenase in gingival crevicular fluid in affected sites of patients with adult periodontitis but not of patients with localized juvenile periodontitis and that the fibroblast type interstitial collagenase is the predominant collagenase type in gingival crevicular fluid in affected sites of patients with localized juvenile periodontitis and the neutrophil collagenase in adult periodontilis gingival crevicular fluid. Furthermore, specific tetracycline inhibition can be used as a simple and practical “probe” to identify the cellular source of interstitial collagenases from in vivo samples.
Reduction in adherence of Actinomyces viscosus after exposure to low‐frequency acoustic energy
Authors: McInnes C. , Engel D. , Moncla B. J. , Martin R. W.
Published: December 2007

The ability of low‐frequency (200 Hz) acoustic energy to reduce the adherence of Actinomyces viscosus T14V to saliva‐treated hydroxyapatite (SHA) disks was studied. An acoustic pressure range between 0 and 65 kPa and exposure durations between 0 and 8 min were used to study the levels necessary to significantly alter adherence. The effects of acoustic exposure on both bacteria in liquid and bacteria already adhering to SHA disks were studied. A modified enzyme‐linked immunosorbent assay was used to assess bacterial adherence. For bacterial suspensions exposed prior to addition to SHA disks, it was found that reductions in adherence were greater for lower bacterial concentrations. Exposure of bacteria already adhering to SHA disks resulted in a decrease in adherence that was independent of the bacterial concentration and linearly related to the logarithm of the exposure duration. In addition to affecting adherence, acoustic energy also dispersed bacterial aggregates. Our results support the concept that low‐frequency sonic energy applied orally may be of therapeutic value in reducing adherence and colonization of the teeth by plaque bacteria.
The age‐dependence of bacterial presence on oral epithelial surfaces in vivo
Authors: Vaahtoniemi L. H. , Räisänen S. , Stenfors L.‐E.
Published: December 2007

Epithelial cells obtained by gentle scraping with a brush tip from the gingival margin of d 11 or 51, adjacent labial mucosa and buccal mucosa of children, adolescents and adults were stained with acridine orange and examined under a fluorescence microscope. The amount of bacteria appearing on the epithelial cells was assessed and the form of the adhered bacteria was evaluated. An age‐related descending trend (negative Pearson's r in all sites) could be seen in the number of colonized cells (> 50 bacteria present) in gingival, labial and buccal areas. Adolescents and adults had significantly fewer epithelial cells with colonization of bacteria in the labial and buccal areas compared with children under 6 years. Only cocci‐formed bacteria were seen associated with the epithelial cells. By studying bacterial adhesion according to methods outlined in the present study, it should be possible to more closely investigate the bacteria‐host relationships as they appear in nature.
Coaggregation studies of the Eubacterium species
Authors: George K. S. , Falkler W. A.
Published: December 2007

Eubacterium species are gram‐positive anaerobic rods that are frequently isolated from subgingival plaque of periodontal pockets. Five Eubacterium species were tested for their ability to coaggregate with 33 oral bacterial strains. Using visual and turbidimetric assays, Coaggregation was observed among Eubacterium brachy, Eubacterium nodatum, Eubacterium alactolyticum and Eubacterium limosum strains only when tested with Fusobacteriitm nucleatum strains; Eubacterium saburreum displayed only weak coaggregation ability. Coaggregation between F. nucleatum and the Eubacterium species was observed over a wide range of concentrations of each organism. The F. nucleatum strains contained a heat labile and the Eubacterium species a heat stabile Coaggregation receptor. Arginine, histidine, lysine and glycine inhibited the Coaggregation between F. nucleatum and the Eubacterium species. Sugars and other amino acids tested did not inhibit the observed Coaggregation. Rabbit anti‐F nucleatum serum completely inhibited Coaggregation, but anti‐E. brachy serum and normal rabbit serum did not. As these anaerobic microorganisms are frequently isolated from the same oral lesions, the surface interactions observed may be important in the pathogenesis of these polymicrobic infections.
Inhibition of Candida albicans by the peroxidase/SCN−/H2O2 system
Authors: Lenander‐Lumikari M.
Published: December 2007

Effects of the salivary peroxidase (SPO) system on the growth, glucose uptake and metabolic activities of oral bacteria are well documented but the effects on oral fungi are virtually unknown. Therefore, the viability of Candida albicans (ATCC 28366) exposed to the peroxidase/SCN−/H2O2: system was studied in sterilized saliva, in phosphate‐buffered saline (PBS) and in potassium chloride. The growth of C. albicans in glucose‐supplemented saliva was faster at pH 5.5 than at pH 7. The addition of the complete SPO (or lactoperoxidase) system to either sterilized saliva, KC1 (50 μM) or PBS at pH 5.5 inhibited dose‐dependently the viability of C. albicans in KC1, but no inhibition was found in PBS or saliva. Maximal inhibition was achieved in 2 h and with > 320 μM of peroxidase‐generated HOSCN/OSCN−. However, physiological salivary concentrations of phosphate (> 1.0 μM) and PBS blocked the antifungal effect of HOSCN/OSCN−. The relative proportions of SCN− and H2O2: were critical to the antifungal effects. With 0.2 mM KSCN, a complete loss of viability was achieved, though the HOSCN/OSCN− concentrations did not exceed 100 μM. It is concluded that C. albicans is sensitive to HOSCN/OSCN− but salivary concentrations of phosphate block the antifungal effect of the peroxidase systems.
Evaluation of a non‐radioactive DMA probe for detecting Porphyromonas gingivalis in subgingival specimens
Authors: Tay F. , Liu Y. B. , Flynn M. J. , Slots J.
Published: December 2007

This study compared the ability of a nonradioactive digoxigenin‐labeled DNA probe and anaerobic culture to identify subgingival Porphyromonas gingivalis. Total cellular DNA from P. gingivalis ATCC 33277T was labeled using the GeniusTM kit from Boehringer Mannheim Biochemicals. Anaerobic culture was performed using VMGA III transport medium and enriched brucella blood agar. The DNA probe could detect as little as 1000 P. gingivalis cells added to supragingival plaque. Also, the probe could detect P. gingivalis when it was present in proportions too low to be visualized on overgrown bacterial plates. The probe showed no visible reaction with strains of various oral species or with thousands of non‐P. gingivalis colonies from plaque samples. VMGA III could maintain the viability of P. gingivalis for up to 6 days, as evidenced by DNA probing of colony blot of subgingival cultures. A total cellular DNA probe for detecting P. gingivalis seems to offer a simple and reliable method of detecting the organism in subgingival specimens.
Oral streptococcal colonization of infants
Authors: Smith D. J. , Anderson J. M. , King W. F. , van Houte J. , Taubman M. A.
Published: December 2007

The objective of this study was to determine the prevalence and proportions of different streptococcal species among the streptococcal flora during infancy. A total of 60 oral samples were collected by oral swabbing of the buccal mucosa and alveolar ridges of 18 infants before tooth eruption and from buccal and lingual surfaces of teeth after tooth eruption. A total of 549 isolates on mitis salivarius agar were speciated, principally by recently revised biochemical criteria of Kilian et al. Streptococcus mitis biovar 1 predominated, both in prevalence (89%) and proportion of oral streptococci recovered in each sample (median = 87% of streptococcal flora). Streptococcus salivarius was also prevalent (94%) but generally represented a small percentage of the total streptococcal flora (median = 3%). Streptococcus oralis and Streptococcus anginosus strains were detected in approximately one third of predentate and dentate infants in the first year of life. Streptococcus sanguis strains were not detected before tooth eruption, but could be detected in 7/14 of the infants with teeth. Thus, S. mitis constitutes the major component of the initially colonizing streptococcal microbiota of the young infant.
Attachment of Treponema denticola strains to monolayers of epithelial cells of different origin
Authors: Keulers R. A. C. , Maltha J. C. , Mikx F. H. M. , Wolters‐Lutgerhorst J. M. L.
Published: December 2007

The attachment of 10 different Treponema denticola strains to monolayers of 4 types of epithelial cells derived from rat palatal epithelium, guinea pig ear, human buccal epithelium and human corneal epithelium was screened microscopically. Most T. denticola strains were able to attach to all four types of epithelial cells. The T. denticola strains seemed to attach better to epithelial cells derived from primary cultured material. The T. denticola strains showed different degrees of attachment. Scanning electron microscopy studies revealed that the attachment of T. denticola was not only tip‐associated but occurred also at random points in close contact with microvilli of the epithelial cells. Attached spirochetes were non‐uniformly distributed over the monolayers, indicating the presence of receptive subpopulations of epithelial cells in the monolayers.
Hybridization patterns of Actinobacillus actinomycetemcomitans serotypes a‐e detected with an rRNA gene probe
Authors: Saarela M. , Asikainen S. , Jousimies‐Somer H. , Asikainen T. , von Troil‐Lindén B. , Alaluusua S.
Published: December 2007

This study reports a genetic characterization of Actinobacillus actinomycetemcomitans strains in relation to serotypes by using rRNA gene restriction patterns. Eighty‐eight clinical strains were isolated from 20 unrelated subjects at one or several occasions. The strains were serotyped by using serotype‐specific rabbit antisera against serotypes a, b, c, d or e. Three subjects harbored 2 A. actinomycetemcomitans serotypes, 15 subjects I serotype and 2 subjects untypable strains. Chromosomal DNA was digested with restriction endonuclease ClaI, BamHI, BglI or HindIII and hybridized to the rrnB ribosomal RNA operon of the Escherichia coli chromosome. Isolates belonging to the same serotype were genetically identical in the same individual but nonidentical if they belonged to different serotypes. Isolates of the same or different serotypes were genetically nonidentical in different individuals. The banding patterns of A. actinomycetemcomitans isolates recovered from the same individuals during several years always remained identical. The hybridization method using pKK3535 as a probe seemed suitable as an epidemiological tool for comparing the clonal identity of A. actinomycetemcomitans strains.
Salivary effects on polymorphonuclear leukocyte functions
Authors: Fumarulo R. , Giordano D. , Laforgia A. , Larocca A. , Quarto M.
Published: December 2007

Respiratory burst, enzymatic degranulation and bacterial killing were investigated on peripheral blood polymorphonuclear leukocytes (polymorphonuclear leukocytes) incubated with a pool of salivary fluids elicited from healthy donors. Low saliva concentrations primed polymorphonuclear leukocytes for enhancement of O2 consumption, O2‐ and β‐glucuronidase release and Staphylococcus aureus killing. Whole saliva, on the contrary, depressed all tested phagocytic activities.
Cytotoxicity of Porphyromonas gingivalis toward cultured human gingival fibroblasts
Authors: Morioka M. , Hinode D. , Nagata A. , Hayashi H. , Ichimiya S. , Ueda M. , Kido R. , Nakamura R.
Published: December 2007

Direct Cytotoxicity of black‐pigmented anaerobic rods was studied on the confluent monolayer of human gingival fibroblasts in vitro. Only strains of Porphyromonas gingivalis caused morphological alteration (cell‐rounding) and notable depression of viability of fibroblasts. To determine the location of the Cytotoxicity, bacterial surface components, i.e., outer membrane, lipopolysaccharide, fimbriae and outer membrane vesicles were prepared from P. gingivalis and their cytotoxicity was assessed. Among these preparations, only outer membrane vesicles are supposed to have high affinity to human gingival fibroblasts, and the cytotoxicity of outer membrane vesicles was found to be much stronger than that of the other constituents. This cytotoxic factor seemed to consist largely of protein and to be associated with the enzyme activity of outer membrane vesicles. The effects of some protease inhibitors and L‐cysteine on the cytotoxicity of outer membrane vesicles suggest that the mechanism of cell‐rounding is different from that of cell death.
Viscosity‐dependent locomotion of oral spirochetes
Authors: Klitorinos A. , Noble P. , Siboo R. , Chan E. C. S.
Published: December 2007

Spirochetes are thought to remain motile in environments (such as intercellular spaces) that immobilize extracellularly flagellated eubacteria. This attribute suggests that the viscosity of the milieu is of importance to locomotion. We sought to determine the interdependence of oral spirochete locomotion with media viscosity. Video time‐lapse microscopy using darkfield optics was used. The motility of the spirochetes in media of different viscosities (various concentrations of Noble agar was measured. Treponema denticola exhibited the fastest speed (18.7 ± 4.4 μ/min) at a viscosity of 30 mPa s. The highest speeds for Treponema vincentii and Treponema socranskii were 41.9 ± 14.9 and 33.4 ± 13.2 μm/min, respectively, at 88 mPa s. These data show that optimal migration of spirochetes is viscosity‐dependent. The results support the hypothesis that such viscosity‐dependent locomotion could be a virulence factor that enables oral spirochetes to initiate and sustain periodontal disease.
The role of reactive oxygen intermediates in the pathogenesis of chronic apical periodontitis
Authors: Marton I. J. , Balla G. , Hegedus C. , Redl P. , Szilagyi Z. , Karmazsin L. , Kiss C.
Published: December 2007

The level of malondialdehyde, a stable end product of lipid peroxidation induced by reactive oxygen intermediates and the activity of two potent antioxidant enzymes, superoxide dismutase and glutathione peroxidase, was investigated in tissue homogenates of 22 surgical periapical granuloma specimens. Malondialdehyde levels were significantly higher and glutathione peroxidase activity was significantly lower in periapical granuloma samples than in healthy gingival tissue homogenates, which were used as controls. The activity of superoxide dismutase was similar in periapical granuloma and in control samples. Our results indicate an altered balance between the production and the elimination of toxic oxygen metabolites in chronic apical periodontitis. We hypothesize that reactive oxygen intermediates, which are being produced by activated phagocytic cells abundantly present in peripical granulomas, can contribute to periapical tissue injury and bone loss in this disease.
Common and specific antigens of several treponemes detected by polyclonal antisera against major cellular proteins
Authors: Nakamura Y. , Umemoto T. , Nakatani Y. , Namikawa I. , Wadood A.
Published: December 2007

Thirteen polypeptide antigens with molecular weights ranging from 34 kDa to 83 kDa were selected and their antigenic behaviors and distribution were examined in 12 strains of microorganisms including Treponema, Borrelia, Leptospira and Leptonema. Immunoblot analysis demonstrated that 45 kDa and 83 kDa polypeptides of Treponema socranskii subsp. buccale ATCC 35534, 53 kDa antigen of Treponema denticola ATCC 33520 and 44 kDa polypeptide of the strain G7201 were strain‐specific. The 34, 62, 66 and 84 kDa polypeptide antigens were detected in all 8 treponemal strains examined. T. denticola ATCC 33520 and ATCC 35404 possessed 38 kDa, 48 kDa, 52 kDa and 72 kDa common polypeptide antigens. All 12 strains possessed the 84 kDa polypeptide antigen. Immunoelectron microscopy demonstrated that the 34 kDa and 38 kDa polypeptide antigens were located on the axial flagella and that other polypeptide antigens were located on the outer envelopes or wall‐membrane complexes.
Beta‐hemolytic streptococci in advanced periodontitis
Authors: Flynn M. J. , Slots J.
Published: December 2007

The distribution of serotypes of beta‐hemolytic streptococci was examined in 718 periodontitis patients. Subgingival samples were obtained with paper points from the 3 deepest lesions in each patient, transported in VMGA III, plated onto brucella agar with 5% sheep blood and incubated anaerobically for 7 days. Serotyping and speciation were performed with MeritecTM‐Strep Beta‐Hemolytic Streptococcus Grouping Set and the Analytab 20STM Streptococcus System. Beta‐hemolytic streptococci were recovered from 33.7% of patients and averaged 10.5% of the total viable counts in culture‐positive subjects. The organisms occurred with higher prevalence in patients 35 years or older than in younger patients. The predominant serotypes were F (62.9%), non‐typeable (18.1%), B (6.9%), C (6.9%) and G (5.2%). 100% of beta‐hemolytic streptococci were sensitive to penicillin, but less than 5% were sensitive to tetracycline, metronidazole or ciprofloxacin. Beta‐hemolytic streptococci may contribute to inflammatory periodontal disease and may interfere with healing after therapy.
Acquired resistance and persistence of Candida albicans following oral candidiasis in the mouse: a model of the carrier state in humans
Authors: Lacasse M. , Fortier C. , Chakir J. , Côté L. , Deslauriers N.
Published: December 2007

In our experimental model of oral candiasis in the CD1 mouse, the primary infection showed reproducible Candida overgrowth kinetics with a peak level on day 5 of the infection. After day 7, the population stabilized at about 300 colony‐forming units per excised mucosal tissue. The primary infection triggered an inflammatory response that resolved in under 8 days. At this point, the histological pattern of the mucosa reached a new equilibrium between recruited and resident mononuclear cells. The primary infection also rapidly stimulated cellular immunity, as measured from day 4 by a delayed‐type hypersensitivity footpad reaction. Following a second topical challenge with Candida 30 days after the primary infection, the infection was barely delectable and a typical local delayed‐type hypersensitivity reaction occurred between 24–72 h. It is proposed that acquired resistance, in conjunction with low‐level persistence of Candida in our model, mimics the carrier stale in sensitized humans.
Factors influencing the growth and viability of Actinobacillus actinomycetemcomitans
Authors: Sreenivasan P. K. , Meyer D. H. , Fives‐Taylor P. M.
Published: December 2007

The metabolic requirements for the routine growth of Actinobacillus actinomycetemcomitans were investigated by the addition of nutrients to conventional bacteriological and tissue culture media. Commonly used tissue culture media required fetal bovine serum as an additive to sustain bacterial growth rates comparable to those obtained with bacteriological media. The addition of increasing concentrations of yeast extract to bacteriological medium increased the growth rate of several A. actinomycetemcomitans strains. In an attempt to identify the components of yeast extract that enhanced the growth of A. actinomycetemcomitans, a number of vitamins, essential and non‐essential amino acids were tested for their role in promoting growth. The addition of L‐cystine resulted in bacterial growth rates comparable to those with yeast extract. Thiamine increased the growth of several A. actinomycetemcomitans strains but did not result in growth rates comparable to those with yeast extract. The addition of physiological concentrations of steroid hormones to bacteriological medium enhanced the growth of A. actinomycetemcomitans. Additional iron compounds and fat‐soluble vitamins had no influence on A. actinomycetemcomitans growth. However, the requirement of iron for bacterial growth remains unclear. The optimal pH range for growth of A. actinomycetemcomitans was between pH 7.0–8.0 in a medium containing 0.5–1% Nacl. Several interesting observations on the viability of A. actinomycetemcomitans were made. A rapid reduction of A. actinomycetemcomitans viability occurred following suspension in distilled water. The presence of the detergent Triton X‐100 at concentrations above 2% (v/v) also decreased the viability of A. actinomycetemcomitans within 10 min.