Uptake of fluoride by cells of Streptococcus mutans in dense suspensions.

Fluoride uptake by nongrowing cells of Streptococcus mutans GS-5 was assessed by means of the space technique. Uptake was highly concentrative at low fluoride concentrations or low pH. In all, it appeared that fluoride uptake is predictably related to its weak-acid properties and that fluoride can be used, as certain other weak acids are, to estimate intracellular pH.