Abbe K, Takahashi S, Yamada T
J Bacteriol. 1982 Oct;152(1):175-82. doi: 10.1128/jb.152.1.175-182.1982.
Streptococcus mutans JC2 produced formate, acetate, ethanol, and lactate when suspensions were incubated with an excess of galactose or mannitol under strictly anaerobic conditions. The galactose- or mannitol-grown cell suspensions produced more formate, acetate, and ethanol than the glucose-grown cells even when incubated with glucose. The levels of lactate dehydrogenase and fructose 1,6-bisphosphate were not significantly different in these cells, but the level of pyruvate formate-lyase was higher in the galactose- or mannitol-grown cells, and that of triose phosphate was lower in the galactose-grown cells. This suggests that the regulation of pyruvate formate-lyase may play a major role in the change of the fermentation patterns. The cells of S. mutans grown on glucose produced a significant amount of volatile products even in the presence of excess glucose under strictly anaerobic conditions. However, when the anaerobically grown cells were exposed to air, only lactate was produced from glucose. When cells were anaerobically grown on mannitol and then exposed to air for 2 min, only trace amounts of fermentation products were formed from mannitol under anaerobic conditions. It was found that the pyruvate formate-lyase in the cells was inactivated by exposure of the cells to air.
在严格厌氧条件下，当变形链球菌JC2的菌悬液与过量的半乳糖或甘露醇一起孵育时，会产生甲酸盐、乙酸盐、乙醇和乳酸盐。即使与葡萄糖一起孵育，用半乳糖或甘露醇培养的细胞悬液产生的甲酸盐、乙酸盐和乙醇也比用葡萄糖培养的细胞多。这些细胞中乳酸脱氢酶和果糖1,6 -二磷酸的水平没有显著差异，但在半乳糖或甘露醇培养的细胞中，丙酮酸甲酸裂解酶的水平较高，而在半乳糖培养的细胞中磷酸丙糖的水平较低。这表明丙酮酸甲酸裂解酶的调节可能在发酵模式的变化中起主要作用。即使在严格厌氧条件下存在过量葡萄糖，在葡萄糖上生长的变形链球菌细胞也会产生大量挥发性产物。然而，当厌氧生长的细胞暴露于空气中时，葡萄糖仅产生乳酸。当细胞在甘露醇上厌氧生长然后暴露于空气中2分钟时，在厌氧条件下甘露醇仅形成微量发酵产物。发现细胞中的丙酮酸甲酸裂解酶通过细胞暴露于空气中而失活。
