| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
Some human oral treponemes have been associated with soft-tissue damages, and eventually these lead to periodontal tissue destruction in certain types of periodontal disease. We planed to distinguish these diverse microorganisms by molecular and biological characteristics.
1. We examined the phenotypic, serologic, and genetic characteristics of an isolated medium-sized treponeme, compared the results with data for reference species, and proposed a new species, Treponema medium. Its GC content was 51 mole%. The DNA-DNA relatedness of this organism to other Treponema species were less than 30%, suggesting that this microorganism is genetically distinct from the established oral Treponema species.
2. Type I-, IV-, and V-collagen-binding polypeptides (CBPs) were detected in the preparations from both T.denticola and T.socranskii subsp. buccale. Few CBPs, however, were detected in the preparations from T.medium. Immunoelectron microscopy using rabbit antisera against the CBPs demonstrated tha
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t the CBPs were located on the outer envelopes. The adherence of T.denticola to the collagen-coated surfaces was significantly greater than that of T.medium.
3. PCR assay using primers specific for the genomic DNA segment coding 165 rRNA of T.medium was examined for detecting the organism in subgingival plaque samples from patients with periodontitis. The PCR analysis resulted in a single band of the PCR products. The PCR assay detected 10 to 100 T.medium cells. The primers reacted with both T.medium and T.vincentii, while neither of the primers reacted with other oral or non-oral bacterial species. The PCR analysis showed a definite relativity in subgingival plaque samples of patients with moderate to severe periodontitis.
4. T.medium strongly coaggregated with fimbriate P.gin givalis strains, but not with afimbriate strains. Heated P.gingivalis cells lost their ability to bind the heated or unheated T.medium cells. The antiserum against the fimbriae of P.gingivalis ATCC 33277 produced different "aggregates' consisting of P.gingivalis cells with few spirochetes, but the preimmune serum did not disturb the coaggregation reaction. A heat-stable 37kDa surface protein of T.medium attached to the P.gingivalis fimbriae. This is the first report of fimbriae-mediated coaggregation between human oral spirochetes and P.gingivalis. Less
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