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Study of acid production and growth of oral streptococci under low pH and strictly anaerobic conditions.

低pH值和严格厌氧条件下口腔链球菌的产酸和生长研究。

基本信息

批准号：
62570826
负责人：
IWAMI Yoshimichi
金额：
$ 1.28万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

项目摘要

1. Production of formic arid acetic acids by Streptococcus mutatis JC2 decreased and lactic acid increased when the pH of culture medium lowered from 7.0 to 5.5. even under glucose-limitation and strictly anaerobic conditions. Two mechanisms seemed to be involved in the increased production of lactic acid at extracellular pli of 5.5. Firstly, lactate dehydrogenase(LDH) had a higher activity than pyruvate formate-lyase(PFL) in the cells. Secondly, the amount of LDH was increased remarkably in comparison to that of PFL during growth at pH 5.5.2. Anaerobic glycolysis of Streptococcus sanguis ATCC 10556 was inhibited more strongly by fluoride than aerobic glycolysis. The cells of S. sanguis had lower pliosphoenolpyruvate(PEP) potential(intracellular levels of 3-phosphoglycerate, 2-phosphoglycerate and phosphoenolpyruvate) under anaerobic conditions than aerobic conditions. Thus it was suggested that the low PEP potential accounted for the reduced transport of sugar by the PEP-dependent phosphotransport system and consequently the reduced glycolysis of the microorganism under anaerobic conditions.3. The acid produced by streptococci during their sugar metabolism was estimated with a pH-stat and a carboxylic acid analyzer. The amount of titratable acid estimated by the alkaline titration with the pH-stat was larger than the amount of total carboxylic acids estimated with the carboxylic acid analyzer. The results indicated that streptococci produced not only carboxylic acids, such as lactic, formic and acetic acid, but also non-carboxylic acid(s).

1.当培养基的pH值从7.0降低到5.5时，变形链球菌JC 2产生的甲酸和乙酸减少，乳酸增加。即使在葡萄糖限制和严格厌氧条件下也是如此。两种机制似乎参与了乳酸的生产增加在细胞外pli为5.5。首先，乳酸脱氢酶（LDH）的活性高于丙酮酸甲酸裂解酶（PFL）。其次，在pH 5.5.2的生长过程中，LDH的量与PFL相比显著增加。氟对血链球菌ATCC 10556的厌氧糖酵解的抑制作用强于有氧糖酵解。结果表明，S.与有氧条件相比，在厌氧条件下，血吸虫具有较低的磷酸烯醇式丙酮酸（PEP）潜力（3-磷酸甘油酸、2-磷酸甘油酸和磷酸烯醇式丙酮酸的细胞内水平）。因此，这表明低PEP电位导致PEP依赖性磷酸转运系统对糖的转运减少，从而导致微生物在厌氧条件下糖酵解减少.链球菌在糖代谢过程中产生的酸用pH-stat和羧酸分析仪估计。用pH-统计仪通过碱滴定估计的可滴定酸的量大于用羧酸分析仪估计的总羧酸的量。结果表明，链球菌不仅产生羧酸，如乳酸、甲酸和乙酸，而且还产生非羧酸。