Ichiro Takazoe

The Relationship between Serum IgG Levels to Subgingival Gram-negative Bacteria and Degree of Periodontal Destruction

The relationship between the serum IgG antibody titer against seven species of Gram-negative periodontopathic bacteria and clinical parameters (including plaque index, gingival index, periodontal pocket depth, and alveolar bone loss) was studied in 38 subjects. IgG antibody titer against the sonicated antigens was determined by micro-ELISA. A statistically significant correlation was found between the serum antibody titer against B. gingivalis and the degree of clinical parameters, especially pocket depth. The serum IgG levels against the seven micro-organisms in 16 periodontal patients before and after clinical treatment were also determined. Responses to B. gingivalis decreased (p<0.001), whereas responses to E. corrodens (p<0.01) increased slightly. No marked differences were noted between pre- and post-treatment sera in titers against B. intermedius, B. loescheii, F. nucleatum, A. actinomycetemcomitans, and C. ochracea.

Colonization of the Subgingival Area by Bacteroides gingivalis

The initial event in colonization of the subgingival area by B. gingivalis is its attachment to host cells and Gram-positive bacteria in pre-formed plaque. The level of B. gingivalis is partly governed by products of other plaque bacteria, especially by sanguicin. Once B. gingivalis resides in its nidus and starts to proliferate, expulsion of pre-existing residents may occur, especially of attached Gram-positive bacteria, through the inhibitory action of the B. gingivalis product, hematin. The bacteriocin produced by black-pigmented Bacteroides also seems to play an important role in their establishment. Melaninogenicus possessed strong inhibitory activity against Actinomyces species. This was not completely confirmed with fresh isolates of B. gingivalis from advanced periodontitis patients. Various factors other than inhibitory substances produced by B. gingivalis and related bacteria can also affect the colonization of this species. Since the crevice area is influenced by gingival fluid, the nature of specific antibody and the other affecting components should be considered collectively with the interaction between new predominant colonizers and other pre-existing residents.

A Semi-Quantitative Determination of Streptococcus mutans Using Its Adherent Ability in a Selective Medium

A method differentiating the critical level of Streptococcus mutans in whole saliva was developed. The procedure is as follows: 100 μl whole saliva is inoculated into 2 ml of MSB broth, the test tube is set tilted at a 60° angle and incubated aerobically at 37 °C for 24 h. The degree of adherence is then scored. When the adherence score is + + +, S. mutans may be assumed to be present at a level higher than 105/ml of whole saliva. On the other hand, if adherence is scored – or + S. mutans is present at a level lower than 104/ml of whole saliva. The method is useful for handling many samples in preventive practice and epidemiological studies, because of its simplicity.

The Role of Bacteroides Gingivalis in Periodontal Disease

The microbial flora in adult advanced periodontitis lesions is comprised of Gram-negative rods, with Bacteroides gingivalis as one of the major representatives. This review deals with biological properties of surface antigens, hemagglutinin (attachment factor), and capsular structure of B. gingivalis. Sera containing high IgG antibody levels to B. gingivalis enhanced the complement-mediated bactericidal activity in vitro, although the susceptibility to complement-mediated lysis differed among B. gingivalis strains. The protective effect of immunization against B. gingival is infection was examined in hamsters in which cotton threads had been tied to the gingival margins of the mandibular first molar. Repeated oral topical application of hyper-immune sera against B. gingivalis resulted in effective elimination of the organisms from the periodontal lesions in the experimental animals.

Susceptibility of Bacteroides gingivalis to Bactericidal Activity of Human Serum

Susceptibility of Bacteroides gingivalis strains to the complement-mediated bactericidal activity of human serum was examined under anaerobic conditions. Serum containing high concentrations of IgG antibody to B. gingivalis enhanced the bactericidal activity. No enhancement was found in serum which did not contain the specific antibody or in serum absorbed with intact cells. The sensitivity to the killing by pooled serum differed among B. gingivalis strains. Cells of B. gingivalis activated the pooled human serum complement not only through the classic pathway but also through an alternative pathway. It was found that the susceptibility of B. gingivalis to the bactericidal activity was classic-pathway-dependent.

Fatty acid composition and Shwartzman activity of lipopolysaccharides from oral bacteria.

The composition and the nature of the linkage of fatty acids and the Shwartzman activity of lipopolysaccharide (LPS) preparations derived from oral gram‐negative bacteria including Bacteroides gingivalis, Bacteroides loesheii, Eikenella corrodens, Fusobacterium nucleatum, and Actinobacillus actinomycetemcomitans were examined. 3‐Hydroxylated and nonhydroxy fatty acids of various chain lengths were found in all of the LPS preparations. All nonhydroxy fatty acids were found to be ester‐bound, and part of the 3‐hydroxy fatty acids in the LPS of B. gingivalis, E. corrodens, F. nucleatum, and A. actinomycetemcomitans were shown to be involved in ester linkage. It was also suggested that the hydroxy group of the ester‐bound 3‐hydroxy fatty acid of the LPS of F. nucleatum and A, actinomycetemcomitans is at least partly substituted by another fatty acid, but in the LPS of B. gingivalis and E. corrodens it is not. The main amide‐linked fatty acid of the LPS of B. gingivalis, E. corrodens, F. nucleatum, and A. actinomycetemcomitans was 3‐hydroxyheptadecanoic, 3‐hydroxydodecanoic, 3‐hydroxyhexadecanoic, and 3‐hydroxytetradecanoic acid, respectively. The results of the Shwartzman assay showed that the E. corrodens LPS was the most active among the preparations tested, and that the Shwartzman toxicity of Bacteroides LPS is extremely low.

Bacteroides heparinolyticus sp. nov. Isolated from Humans with Periodontitis

We describe a new species of nonpigmented, saccharolytic Bacteroides, Bacteroides heparinolyticus, which is frequently isolated from human periodontitis lesions. This species produces an enzyme that hydrolyzes heparin. The major product from glucose is succinic acid. B. heparinolyticus strains have membranes typical of gram-negative cells and external surface structures that stain with ruthenium red and glutaraidehyde-osmium. The guanine-plus-cytosine content of the deoxyribonucleic acid is 47 to 49 mol%. Strains of this species have negligible deoxyribonucleic acid homology with other Bacteroides species described previously. Strain HEP (= ATCC 35895) is the type strain. B. heparinolyticus strains are serologically distinct from other Bacteroides species on the basis of cell agglutination and gel diffusion tests.

Inhibitory Effects of Funoran on the Adherence and Colonization of Mutans Streptococci

Funoran, a sulfated polysaccharide extracted from the seaweed Gloiopeltis furcata strongly inhibited the absorption of mutans streptococci to saliva-coated hydroxyapatite (S-HA), but enhanced that of Streptococcus sanguis ATCC 10556 and Streptococcus oralis ATCC 10557. Furthermore, funoran had a strong desorption activity against mutans streptococci preadsorbed to S-HA. In the presence of sucrose, the absorption of cells of Streptococcus sobrinus B13, Streptococcus mutans Ingbritt, and S. mutans MT8148R to S-HA was strongly inhibited by 0.01% funoran. The colonization of S. sobrinus 6715 inoculated on the molar teeth of experimental rats that were administered funoran was less frequent than that in a funoran-free group. The mean buccal and lingual, sulcal, and total caries scores of rat groups administered funoran were significantly lower than those of the funoran-free group.

Electron Microscopy of Intracellular Mineralization of Oral Filamentous Microörganisms in Vitro

Recent electron-microscopic observations have revealed that the filamentous micro6rganisms in dental calculus are calcifiable during later stage of calculus formation.l-5 Parallel with these studies that were carried out in vivo, Ennever and Snyder,6 Ennever,7 and Takazoe8 have demonstrated in their histochemical and X-ray diffraction studies that some oral filamentous microorganisms are capable of forming hydroxyapatite intracellularly in vitro. The work being reported dealt with an electron-microscopic study of pure cultures of oral filamentous microorganisms that were experimentally mineralized in a calcifying solution.

Experimental Formation of "Corn Cob" In Vitro

Organisms isolated from corn cob were examined for aggregation with Bacterionema matruchotii. Such aggregations, interpreted as corn cob formation, in vitro, occurred with five isolates identified as Streptococcus sanguis. A cell-surface component of Streptococcus sanguis or a phospholipid-related substance of Bacterione ma matruchotii appeared to be involved.