MICROBIOLOGICAL STUDY ON DENTAL CARIES PREVENTION USING SUGAR SUBSTITUTES

木糖醇抑制变形链球菌（S. mutans）的糖酵解和生长。在本研究中，我们研究了木糖醇在牙菌斑深层的严格厌氧条件下，在不同pH水平下对变形链球菌产酸的抑制作用。木糖醇抑制了葡萄糖产酸的速率，并改变了酸性终产物的形态，使其以乙酸为主，细胞内果糖1,6-二磷酸水平降低，细胞内木糖醇5-磷酸（X5P）积累。这些结果在pH 5.5-7.0时显著，但在pH 5.0时不明显。pH值越高，木糖醇磷酸烯醇丙酮酸磷酸转移酶活性越高，说明木糖醇在pH值越高时能被有效地掺入，由此积累的X5P能更有效地抑制变形链球菌的糖酵解。

Xylitol inhibits the glycolysis and growth of Streptococcus mutans (S. mutans). In this study, we studied the inhibitory effect of xylitol on the acid production of S. mutans at several pH levels under the strictly anaerobic conditions found in the deep layer of dental plaque. Xylitol inhibited the rate of acid production from glucose and changed the profile of acidic end products to formats-acetate dominance, with a decrease in the intracellular level of fructose 1,6-bisphosphate and an intracellular accumulation of xylitol 5-phosphate (X5P). These results were notable at pH 5.5-7.0,but were not evident at pH 5.0. Since the activity of phosphoenolpyruvate phosphotransferase for xylitol was greater at higher pH, it is suggested that xylitol could be incorporated more efficiently at higher pH and that the resultant accumulation of X5P could inhibit the glycolysis of S. mutans more effectively.