FIG. 6.

Stannous chloride prevents uptake of ⁷⁵Se by T. denticola. Actively growing cultures were treated with stannous chloride (5, 10, 25, and 50 μg/ml), followed by the addition of ⁷⁵Se (sodium selenite). Cultures were incubated for 20 min at 37°C. Cells were harvested by centrifugation and washed with phosphate-buffered saline. Total uptake of ⁷⁵Se was analyzed by using a model 1470 gamma counter (Perkin-Elmer, Wellesley, ME) and is reported as percent uptake (compared to level in control). Data shown are from at least three independent cultures. Error bars indicate standard deviations.