APPLICATION OF SUGAR ALCOHOLS COCKTAILS TO HUMAN CARIES PREVENTION

木糖醇抑制变形链球菌的糖酵解和生长。我们研究了木糖醇在几种pH水平下对牙菌斑深层严格厌氧条件下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轮廓，以甲酸-乙酸为主，果糖1，6-二磷酸和木糖醇5-磷酸（X5 P）的细胞内积累的水平下降。这些结果在pH 5.5-7.0下显著，但在pH 5.0下不明显。由于木糖醇的磷酸烯醇式丙酮酸磷酸转移酶活性在较高pH下更高，因此，木糖醇在较高pH下可以更有效地掺入，由此产生的X5 P积累可以更有效地抑制变形链球菌的糖酵解。乳糖（L）或蔗糖（5）作为能量源，但果糖（Fr）对生长的抑制较小。木糖醇抑制来自G、Gal、M、L或5的变形链球菌的洗涤细胞的酸产生（12-83%抑制）。当变形链球菌在木糖醇存在下发酵这些糖时，它们通过磷酸烯醇化酸-木糖醇磷酸转移酶系统（PEP-木糖醇PTS）的活性在细胞内积累木糖醇5-磷酸（X5 P）。然而，在Fr的存在下，没有观察到酸产生的抑制。此外，尽管存在PEP-木糖醇PTS活性，但Fr发酵过程中X5 P的量小于其他糖的量。这些结果表明，沿着XSP的细胞内积累，木糖醇降低变形链球菌的生长和产酸的存在下，除了Fr的各种膳食糖。

Xylitol inhibits the glycolysis and growth of Streptococcus mutans. 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 formate-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.In addtion, xylitol retarded the growth of mutans streptococci in the presence of glucose (G), galactose (Gal), maltose (M), lactose (L) or sucrose (5) as an energy source, though the inhibition of growth on fructose (Fr) was small. Xylitol inhibited acid production by washed cells of S.mutans from G,Gal,M,L or 5 (12-83% inhibition). S.mutans accumulated xylitol 5-phosphate (X5P) intracellularly through activity of the phosphoenolpyruvate-xylitol phosphotransferase system (PEP-xylitol PTS) when they fermented these sugars in the presence of xylitol. However, in the presence of Fr, no inhibition of acid production was observed. In addition, the amounts of X5P during the fermentationof Fr were smaller than those of other sugars in spite of the presence of PEP-xylitol PTS activity. These results suggest that along with the intracellular accumulation of XSP, xylitol decreases the growth and acid production of mutans streptococci in the presence of various dietary sugars except Fr.