Mechanism of acid trelance of oral streptococci

口腔链球菌酸调节机制

• 批准号: 10671732
• 负责人: IWAMI Yoshimichi
• 金额: $ 1.98万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10671732/
• 关键词: NADH; streptococci; sugar metabolism; intracellualr pH; sorbitol; Streptococcus mutans; BCECF; 耐酸性

1. NADH-dependent fluorescence and acid excretion during glucose pulse to washed streptococcal cells were monitored simultaneously. Acid excretion started with addition of glucose. At the same time, the fluorescence dropped quickly to a minimum level and increased to a plateau level. When the acid excretion stopped, the fluorescence increased rapidly from the plateau to a maximum level. The results suggested that pyruvate metabolism started immediately after addition of glucose, then the rate of pyruvate metabolism became equal to the rate of glycolysis, and that the pyruvate metabolism stopped first when the acid excretion stopped.2. Bacterial intracellular pH (pHi) has been considered to be higher than extracellular pH (pHo) even if in the absence of energy source, such as glucose. The pHi and pHo were simultaneously measured when lactic acid was added to the S.mutans, S.sanguinis, S.salivarius cell suspensions. The pHi was measured by the BCECF method in the absence of glucose. The pHi was lower than the pHo at the range of pHo from 7.5 to 5.0 and was kept constant at pHo from 5 to 4. The pHi decreased at pHo from 4 to 3.3. It has been supposed that the rate of sorbitol metabolism in the air-exposed streptococcal cells could be limited by the inactivation of pyruvate formate-lyase by oxygen. The decreased acid production from sorbitol resulted from the reduced rates of the reactions catalyzed by sorbitol 6-phosphate dehydrogenase because of shortage of substrates for these enzymes in addition to the decrease in pyruvate catabolism. In the presence of sorbitol, the air-exposed cells could start to metabolize glucose 2 min after glucose was added, as the intermediates for the glucose transport were accumulated.

1。同时监测葡萄糖脉冲期间NADH依赖性的荧光和酸排泄，同时监测洗涤后的链球菌细胞。酸排泄始于添加葡萄糖。同时，荧光迅速下降至最低水平，并增加到平稳水平。当酸排泄停止时，荧光从高原迅速增加到最大水平。结果表明，丙酮酸代谢在添加葡萄糖后立即开始，然后丙酮酸代谢的速率等于糖酵解速率，而丙酮酸代谢停止后首先停止。2。细菌细胞内pH（PHI）被认为高于细胞外pH（PHO），即使在没有能源（例如葡萄糖）的情况下。当将乳酸添加到S.Mutans，S.sanguinis，S.Salivarius细胞悬浮液中时，同时测量了PHI和PHO。在没有葡萄糖的情况下，通过BCECF方法测量了PHI。 PHI在PHO范围从7.5到5.0的范围内低于PHO，并在PHO下从5到4保持恒定。pHI在PHO下从4降低到3.3。据认为，暴露于空气的链球菌细胞中的山梨糖醇代谢速率可以受到氧气灭活丙酮酸甲酸酯溶性的限制。山梨糖醇的酸产生降低是由于山梨糖醇6-磷酸脱氢酶催化的反应速率降低，因为这些酶的底物不足，除了丙酮酸分解代谢的降低外。在存在山梨糖醇的情况下，添加葡萄糖后2分钟的空气暴露细胞可以开始代谢葡萄糖，因为积累了葡萄糖转运的中间体。

项目成果

H.Miyasawa: "Growth-phase- and pH-dependent xylitol inhibition on acid production of Streptococcus mutans."J Dent Res. 79(in press). (2000)

H.Miyasawa：“生长阶段和 pH 依赖性木糖醇对变形链球菌产酸的抑制。”J Dent Res。

宮澤はるみ: "Xylitolによるミュータンスレンサ球菌の酸産生阻害とそれに及ぼすpHの影響"歯科基礎誌. 42. 92-92 (2000)

Harumi Miyazawa：“木糖醇对变形链球菌产酸的抑制及其 pH 值的影响”《牙科基础杂志》42. 92-92 (2000)。

Y.Iwami: "Intracellular flux of glucose metabolism in streptococcal cells by simultaneous monitoring of NADH-dependent fluorescence and acid excretion under strictly anaerobic conditions."Oral Microbiol Immun. 14. 220-224 (1999)

Y.Iwami：“通过在严格厌氧条件下同时监测 NADH 依赖性荧光和酸排泄来了解链球菌细胞中葡萄糖代谢的细胞内通量。”口腔微生物免疫。

Y.Iwami: "Rate-limiting steps of glucose and sorbitol metabolism in Streptococcus mutans cells exposed to air."Oral Microbiol and Immunol. 15(in press). (2000)

Y.Iwami：“暴露于空气的变形链球菌细胞中葡萄糖和山梨醇代谢的限速步骤。”口腔微生物和免疫学。

Y.Iwami: "Rate-limiting steps of glucose and sorbitol metabolism in Streptococcus mutans cells exposed to air."Oral Microbiology and Immunology. 15. 325-328 (2000)

Y.Iwami：“暴露于空气的变形链球菌细胞中葡萄糖和山梨醇代谢的限速步骤。”口腔微生物学和免疫学。