Effects of environmental fluctuations on sugar metabolisms of plaque bacteria.

环境波动对菌斑细菌糖代谢的影响。

• 批准号: 03454425
• 负责人: YAMADA Tadashi
• 金额: $ 0.45万
• 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 (B)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03454425/
• 关键词: Sugar metabolism; Dental caries; Dental plaque; Streptococci; Actinomyces; Acid production; Anaerobic conditions; Change in pH

When oral streptococci was cultured at low pH in continous culture under strictly anaerobic conditions, more lactate was produced with a concomitant decrease in formate and acetate, compared with at neutral pH. Two mechanisms seemed to be mainly involved in the increased production of lactate at acidic pH in the chemostat. Firstly, lactate dehydrogenase (LDH) had lower optimum pH than that of pyruvate formate-lyase (PFL). Secondly, the amount of LDH was markedly increased due to the acidification in the cells. In contrast to other streptococci S. mutans could produce more acid even at pH 5.1-5.5 because of acid tolerance of ATPase which excrete proton from the cells. These properties were considered to render S. mutans higher cariogenicity.It is essential for plaque microorganisms to keep intracellular NADH/NAD balance under anaerobic conditions. Oral streptococci employed the PFL system to metabolize sorbitol anaerobically. Lactobacilli could regenerate NAD to keep the balance via the conversion of acetate into ethanol and metabolize sorbitol in the presence of availabe acetate, even when PFL was irreversibly inactivated. Actinomyces could regenerate NAD via succinate pathway when bicarbonate was available, and increased the rate of acid production three- to four-fold. These effects were not observed in streptococci.Various environmental factors affect sugar metabolisms of several plaque microorganisms, but these effects are quite different depend on bacterial species.

当口腔链球菌在严格厌氧条件下的低pH连续培养中培养时，与在中性pH下相比，产生了更多的乳酸，同时甲酸和醋酸盐的减少。在酸性pH下，趋化器中乳酸产量的增加似乎主要涉及两个机制。首先，乳酸脱氢酶（LDH）的最适pH值低于丙酮酸解甲酸酶（PFL）。其次，由于细胞酸化，乳酸脱氢酶的数量明显增加。与其他链球菌相比，变形链球菌在pH为5.1-5.5时也能产生更多的酸，这是由于atp酶的耐酸性，atp酶能从细胞中分泌质子。这些特性被认为使变形链球菌具有更高的致病性。在厌氧条件下，斑块微生物保持细胞内NADH/NAD平衡是必不可少的。口服链球菌采用PFL系统厌氧代谢山梨醇。即使PFL不可逆失活，乳酸杆菌也可以通过将醋酸转化为乙醇来再生NAD以保持平衡，并在有效醋酸存在的情况下代谢山梨醇。当碳酸氢盐存在时，放线菌可以通过琥珀酸途径再生NAD，使产酸速率提高3 ~ 4倍。在链球菌中没有观察到这些作用。不同的环境因素会影响几种菌斑微生物的糖代谢，但这些影响因细菌种类而异。

项目成果

N.Takahashi: "Stimulatory effect of bicarbonate on the glycolysis of Actinomyces viscosus and its biochemical mechanism." Oral Microbiol.Immunol.7. 165-170 (1992)

N.Takahashi：“碳酸氢盐对粘性放线菌糖酵解的刺激作用及其生化机制。”

Y. Iwami: "Change of intracellular pH in Streptococcus mutans during sugar metabolism" Jpn. J. Oral Biol.34. 73 (1992)

Y. Iwami：“糖代谢过程中变形链球菌细胞内 pH 值的变化”Jpn。

K.Abbe: "Oxygen and the sugar metabolism in oral streptococci" Proc. Finn. Dent. Soc.87. 477-487 (1991)

K.Abbe：“口腔链球菌中的氧和糖代谢”Proc。

Y.Iwami: "Acid production by streptococci growing at low pH in a chemostat under anaerobic conditions." Oral Microbiol.Immunol.7. 304-308 (1992)

Y.Iwami：“链球菌在厌氧条件下在恒化器中的低 pH 值下生长产生酸。”

N.Takahashi: "Stiumulatory Effect of Bicarbonate on on the Glycolysis of Actinomyces viscosus and its biochemical mechanism." Oral Microbiology and Immunology. (1992)

N.Takahashi：“碳酸氢盐对粘性放线菌糖酵解的刺激作用及其生化机制。”