| Project/Area Number |
13672158
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | Kyushu University |
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Principal Investigator |
OHO Takahiko University Dental Hospital, Assistant Professor, 歯学部附属病院, 講師 (50160940)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMAZAKI Yoshihiro Faculty of Dental Science, Research Associate, 大学院・歯学研究院, 助手 (10291519)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2001: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Dental caries / Streptococcus mutans / Adherence / Bovine milk / Lactoferrin |
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| Research Abstract |
Bovine milk inhibits the saliva-induced aggregation of S. mutans. In this study, the milk component that possesses inhibitory activity against this aggregation was isolated and found to be lactoferrin. Surface plasmon resonance analysis indicated that bovine lactoferrin binds more strongly to salivary agglutinin than to recombinant PAc. To identify the saliva-binding region of bovine lactoferrin, 11 truncated bovine lactoferrin fragments were constructed. A fragment corresponding to the C-terminal half of the lactoferrin molecule had a strong inhibitory effect on the saliva-induced aggregation of S. mutans, whereas a fragment corresponding to the N-terminal half had a weak inhibitory effect. Seven shorter fragments corresponding to lactoferrin residues 473 to 538 also showed a high ability to inhibit the aggregation of S. mutans. These results suggest that residues 473 to 538 of bovine lactoferrin are important in the inhibition of saliva-induced aggregation of S. mutans.
Next, the effect of bovine milk lactoferrin on S. mutans adherence to a salivary film was investigated. Bovine lactoferrin molecule and relatively long lactoferrin fragments containing residues 473-538 strongly inhibited S. mutans adherence to saliva-coated hydroxyapatite beads. Each cysteine residue in Lf411 (residues 473-538) was substituted by a serine residue, and the mutants Lf411-C481S and Lf411-C532S strongly inhibited S. mutans adherence. These results suggest that the functional domain of lactoferrin that binds to a salivary film lies in residues 473-538, and that the region might be concealed by disulfied bond formation between Cys481 and Cys532 in the Lf411 fragment.
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