| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2005: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
1.Analysis of major outer membrane proteins among various P.gingivalis strains.
Major outer membrane proteins, such as RagA and Pgm6/7,were found in all strains tested in a similar distribution pattern. However, mobility and reaction of RagB against specific antibody was different among strains, indicating RagB heterogeneity.
2.Effect of culture environment factors on the expression of P.gingivalis major outer membrane proteins
When effect of several factors was examined on the expression of major outer membrane proteins, temperature was the most important factor. As temperature increased, expression of RagA,RagB and gingipains as well as fimbriae and short fimbriae decreased.
Then, we used continuous culture in which regulation of culture environment was possible. With increase of growth rate, production of fimbriae and short fimbriae increased, while amount and activity of gingipains decreased. In a nutrient-poor medium, fimbriae and short fimbriae decreased. When atmosphere was changed
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from anaerobic to aerobic condition, activity of gingipains decreased. Protein spots whose amount increased under oxidative stress was observed by 2-dimensional gel electrophoresis, and those were identified by mass spectrometry
3.Characterization of major outer membrane proteins using gene-deletion mutants.
Major outer membrane proteins Pgm6/7, which were homologous to OmpA protein from Escherichia coli, existed in outer membrane forming heterotrimers. Since numerous vesicle-like structures were observed in the case of Pgm6/7 gene-deletion mutants by electron microscopy, Pgm6/7 might be involved in stabilization of outer membrane integrity. Since construction of RagA and RagB-deletion mutants have been finished, we are characterizing the mutants.
4.Immunological reactions of sera from patients with periodontitis to P.gingivalis major outer membrane proteins.
To examine immunoreactive antigens in P.gingivalis, sera from patients with periapical periodontitis were used. More than half of the sera showed strong immunological reaction to P.gingivalis cell components, especially, outer membrane proteins RagB and gingipains. Clinical symptoms such as percussion and periapical translucency were related to immnoreactivity to P.gingivalis. Less
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