| Project/Area Number |
10470387
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional basic dentistry
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
YAMADA Tadashi School of Dentistry, Tohoku Univ., Professor, 歯学部, 教授 (50005021)
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| Co-Investigator(Kenkyū-buntansha) |
IWAMI Yoshimichi School of Dentistry, Tohoku Univ., Associate Professor, 歯学部, 助手 (60005030)
TAKAHASHI Nobuhiro School of Dentistry, Tohoku Univ., Associate Professor, 歯学部, 助教授 (60183852)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥10,400,000 (Direct Cost: ¥10,400,000)
Fiscal Year 1999: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1998: ¥9,300,000 (Direct Cost: ¥9,300,000)
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| Keywords | Streptococcus mutans / sugar metabolism / metabolism of sugar alcohols / sorbitol / xylitol / oxygen / inhibition of metabolism |
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| Research Abstract |
1. The aim of this study was to examine the effect of temporary exposure of the streptococcal cells to air on the intracellular flux of glucose and sorbitol metabolism by measuring acid excretion, fluorescence dependent on cellular level of NADH, glycolytic intermediates and enzyme activities. The exposure of cells to air decreased the acid excretions during glucose and sorbitol metabolism. The analysis of the glycolytic intermediates and the fluorescence suggested that the reduced level of acid excretion in the air-exposed glucose metabolizing cells resulted from the decrease in pyruvate catabolism. In the presence of sorbitol, the decreased acid production resulted from the reduced rates of the reactions catalyzed by sorbitol-phosphoenolpyruvate phosphotransferase and sorbitol 6-phosphate dehydrogenase because of shortage of substrates for these enzymes in addition to the decrease in pyruvate catabolism.
2. The aim of this study was to examine glucose and sorbitol metabolism in Strept
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ococcus mutans cells exposed and not exposed to air at the coexistence of these compounds by measuring acid excretion, levels of fluorescence dependent on cellular NADH and glycolytic intermediates. A part of bacterial cells grown under strictly anaerobic conditions (anaerobic cells) was exposed temporarily to air (aerobic cells). When glucose was added to the anaerobic cells metabolizing sorbitol, the acid excretion was increased. At the same time, the level of NADH was decreased and then reached to the higher plateau level than that during glucose metabolism. The aerobic cells neither metabolized sorbitol nor contained cellular intermediates. At 2 min after glucose was added in the presence of sorbitol, the acid excretion was started slowly and the intermediates appeared. The level of NADH was decreased at first and then increased. These results suggested that the anaerobic S. mutans cells metabolized glucose and sorbitol simultaneously, and that in the presence of sorbitol the aerobic cells could start to metabolize glucose by addition of glucose at 2 min after glucose was added, as the intermediates (PEP potential) for the glucose transport were accumulated. Less
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