| Project/Area Number |
62560313
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied veterinary science
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| Research Institution | Kitasato University |
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Principal Investigator |
SUGII Shunji Kitasato University, 衛生学部, 講師 (70162865)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1988: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1987: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Carbohydrate specificity / bacterial lectin / enterotoxin / Vibrio choleare / 毒素原性大腸菌 |
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| Research Abstract |
The carbohydrate specificities of the combining sites of cholera toxin (CT) and heat-labile enterotoxin (LT) produced by enterotoxigenic escherichia coli were studied by hemagglutination inhibition and competitive binding assays. Both toxins were found to strongly agglutinate enzyme-treated human and animal erythrocytges but not untreated erythrocytes. Hemagglutination by both CT and LT was effectively inhibited by mono- and disaccharides, and glycoproteins but not by ganglioside GM_1 at the highest concentration used, whereas the binding of ^<125>I-labeled these toxins to treated human erythrocytes was effectively inhibited by ganglioside GM_1 but not by other subsatnces.
These suggest that the interaction of these toxins with ganglioside GM_1 may be somehow different in hemagglutination. In competitive binding assays, the binding of ^<125>I-labeled these toxins to human erythrocytes was most effectively inhibited by ganglioside GM_1 which was at least 10^4 times more potent than glycoproteins. These suggest that the predominant binding substance on human erythrocytes for both CT and LT may be ganglioside GM_1. Of different gangliosides tested as inhibitors, their inhibitory abilitirs were as follows: GM_1 > GD_<1b> > GD_<1a> > GM_2 > GT_<1b> > GM_3. From chemical structures of these gangliosides reported previously, the combining sites of both CT and LT may be specific for terminal nonreducing Gal-GalNAc-linked portion of genglioside GM_1.
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