1990 Fiscal Year Final Research Report Summary
Role of Inhibitors in Bacterial Aggregation by Bacteroides Gingivalis
| Project/Area Number |
01480482
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
小児・社会系歯学
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| Research Institution | Osaka University |
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Principal Investigator |
TSUNEMITSU Akira Osaka Univ. Fac. of Dent. Prof., 歯学部, 教授 (40034160)
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| Co-Investigator(Kenkyū-buntansha) |
IWAKURA Katsuko Osaka Univ. Fac. of Dent. Res. Asst., 歯学部, 助手 (60168549)
AMANO Atsuo Osaka Univ. Fac. of Dent. Res. Asst., 歯学部, 助手 (50193024)
TAKESHITA Tetsuo Osaka Univ. Fac. of Dent. Res. Asst., 歯学部, 助手 (10163396)
INOSHITA Eiji Osaka Univ. Fac. of Dent. Res. Asst., 歯学部, 助手 (00135724)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Bacteroides gingivalis / Bacterial aggregation / Histatin / Fibrinogen |
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| Research Abstract |
In this study, we explored the effects of human saliva and plasma on the coaggregation of Bacteroides gingivalis and Streptococcus Bmitis. We also investigated the mechanism on inhibition of the coaggregation by inhibitors such as histatin and fibrinogen. Human plasma and saliva were able to inhibit the coaggregation in a dose dependent reaction. Histidine-rich peptide as the potent inhibitor was purified from human parotid saliva. The peptide contained 12 amino acid residues whose amino acid sequence was unexpectedly the same as histatin 8. The histain was able to bind to B. Gingivalis but not S. Mitis cells. The number of histatin binding sites per cell was 36,000, and the dissociation constant was on the order of 10^<-16> M. Fibrinogen was the most potent inhibitor of the plasma-derived proteins tested. Preincubation of either B. Gingivalis or S. Mitis with fibrinogen disappear e inhibitory effect of fibrinogen. When several thiol-protease inhibitors was added to the preincubation mixture with B. Gingivalis, the inhibition of fibrinogen reappeared. While addition the protease inhibitors to the preincubation mixture with S. Mitis did not affect the coaggregation activity. Fibrinogen was also able to bind B. Gingivalis but not S. Mitis cells. Furthermore, the coaggregation and the binding of fibrinogen to B. Gingivalis cells were inhibited by L-arginine and L-lysine, although these reactions were not unaffected by the sugars tested. Thus, the inhibition of coaggregation by histatin and fibrinogen caused by binding of both inhibitors to B. Gingivalis, and may be involved in cationic amino acid residues in molecule of the inhibitors.
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