BINDING OF F-18 BY THE ORAL BACTERIUM, STREPTOCOCCUS-MUTANS

The binding of carrier-free fluorine-18 by resting cells of the cariogenic microorganism Streptococcus mutans GS-5 were assessed. A Ge(Li) γ-ray spectrometer attached to a 4096 channel pulse-height analyzer was used to measure the 18F bound and to check the radiochemical purity of 18F. The binding was dependent on time, pH, the amount of 18F used, the cell status and the fluoride concentration. The adherence of 18F to Strep. mutans did not require addition of an exogenous energy source, such as glucose, and proceeded equally well at 4-37 °C or at varying oxygen tensions. Under optimal conditions, resting cells of the strain bound approximately 109 atoms of 18F and more than 1013 atoms of total fluoride in the presence of 10 parts/106 NaF per mg dry weight of cells that were not removed by repeated washings. © 1979.