Effects of xylitol and fluoride on the response to glucose pulses of Streptococcus mutans T8 growing in continuous culture.
Streptococcus mutans T8 was grown glucose-limited at pH 7.0 in a chemostat and pulsed, under pH free-fall conditions, with glucose, xylitol or a mixture of the two. Experiments were conducted in the absence or continual presence of low levels (1 mmol.l-1) of fluoride. Culture filtrates of samples taken at frequent intervals were assayed for carbohydrate and fermentation end-products. Fluoride had little effect on the organism's response to glucose until the culture pH fell to ca. 5.0, at which point the rate of lactate production was reduced some 3-fold. Xylitol affected the response to glucose but its effect was most marked in the presence of fluoride. Under these conditions, the rate of lactate production was reduced at least 3-fold, the pH did not fall to 5.0 and only about 50% of the added glucose was consumed. This suggests that xylitol can augment the metabolic effects on S. mutans of low levels of fluoride.
Rogers
A H
AH
Department of Dentistry, University of Adelaide, South Australia.
Bert
A G
AG
D005459:Fluorides / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D007773:Lactates / Q000096:biosynthesis; D013295:Streptococcus mutans / Q000187:drug effects* / Q000378:metabolism; D014993:Xylitol / Q000494:pharmacology*
D007773:Lactates; D005947:Glucose; D005459:Fluorides; D014993:Xylitol