Biochemical and genetical characterization of Glucosyltransferases from Streptococcus mutans, and application for the estimation of the caries
Grant-in-Aid for Scientific Research (A)
|Allocation Type||Single-year Grants|
|Research Institution||Osaka University|
SOBUE Shizuo Department of Pedodontics, Osaka University Faculty of Dentistry, Professor, 歯学部, 教授 (60029973)
FUJIWARA Taku Department of Pedodontics, Osaka University Faculty of Dentistry, Assistant Prof, 歯学部・附属病院, 講師 (00228975)
南 貴洋 大阪大学, 歯学部・附属病院, 助手 (00263294)
|Project Period (FY)
1995 – 1997
Completed(Fiscal Year 1997)
|Budget Amount *help
¥10,400,000 (Direct Cost : ¥10,400,000)
Fiscal Year 1997 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1996 : ¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1995 : ¥7,500,000 (Direct Cost : ¥7,500,000)
|Keywords||Streptococcus mutans / glucosyltransferase / sucrose dependent adherence / gtf gene|
Steptococcus mutans has been implicated as a principal causative agent in the development of human dental caries. One of the most important virulence factors of this organism is a group of enzymes synthesizing watersoluble and -insoluble glucans from sucrose called glucosyltransferases (GTases). S.mutans produces at least three distinct GTases ; GTase-I,GTase-SI and GTase-S.The glucans synthesized de novo by these GTases contribute to the adherence of this organism to the tooth surface.
In this study, biochemical and molecularbiological properties of the GTases were investigated.
Results were as follows :
1. GTase-I and GTase-SI were separated by Bio-Scale Ceramic Hydoroxyapatite Type I Column.
2. Three GTase genes (gtfB,gtfC and gtfD) were cloned and sequenced from clinically isolated strains of S.mutans, MT8148 (serotype c), MT4239 (c), MT4245 (e), MT4467 (e) and MT4251 (f), respectivily.
3. Comparison of the gtf genes revealed that interstrain difference of gtfB and gtfD was limited, while gtfC showed significant interstrain variations.
4. GTase genes were inavtivated by insertion mutagenesis by allelic exchange and GTase (s) deficient mutants were generated.
5. Escherichia coli-Streptococcus shuttle vectors carrying the gtfB and gtfC gene were generated, then transformed into the GTase deficient mutants.
6. Determination of sucrose-dependent adherence of the GTase (s) deficient and complemented mutants indicated that GTase-SI dose play an essential role in the production of adhesive glucan that can lead to firm cellular adherence to solid surfaces.
Research Output (6results)