| Project/Area Number |
11470451
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | Osaka University |
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Principal Investigator |
SOBUE Shizuo Graduate School of Dentistry, Osaka University, Professor, 大学院・歯学研究科, 教授 (60029973)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Taku Dental Hospital, Osaka University, Assistant Professor, 歯学部・附属病院, 講師 (00228975)
OOSHIMA Takashi Graduate School of Dentistry, Osaka University, Associate Professor, 大学院・歯学研究科, 助教授 (80116003)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥13,700,000 (Direct Cost: ¥13,700,000)
Fiscal Year 2001: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2000: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1999: ¥7,700,000 (Direct Cost: ¥7,700,000)
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| Keywords | Streptococcus oralis / glucosyltransferase / mutans streptococci / PCR / S. oralis / S. mutans / グルコシウトランスフェラーゼ |
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| Research Abstract |
Streptococcus oralis is a member of the oral streptococcal family and an early colonizing microorganism in the oral cavity of humans. S. oralis is known to produce glucosyltransferase (Gtase), which synthesizes glucans from sucrose. The enzyme was purified chromatographically from a culture supernatant of S. oralis ATCC10557. The purified enzyme, Gtase-R, showed a 173 kDa molecular mass and a 6.3 pi value. This enzyme mainly synthesized water soluble glucans with no primer dependency. Addition of Gtase markedly enhanced the sucrose-dependent resting cell adhesion of Streptococcus mutans at a similar level as found in growing cells of S. mutans. The antibody against Gtase-R inhibited the glucan synthesizing activities of Streptococcus gordonii and Streptococcus sanguis, as well as S. oralis. The N-terminal amino acid sequence of Gtase-R exhibited no similarities to known Gtase sequences of oral streptococci. Using degenerate PCR primers, an 8.1 kb DNA fragment, carrying the gene (gtfR) coding for Gtase-R and its regulator gene (rgg), was cloned and sequericed. Comparison of the deduced amino acid sequence revealed that the rgg genes of S. oralis and S. gordonii exhibited a close similarity. The gtfR gene was found to possess a species specific nucleotide sequence corresponding to the N-terminal 130 amino acid residues. Insertion of erm or aphA into the rgg or gtfR gene resulted in decreased Gtase activity by the organism and changed the colonial morphology of these transformants. These results indicate that S. oralis Gtase may play an important role in the subsequent colonizing of mutans streptococci.
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