FIG 4.

Efflux of potassium ions from living cells due to the rapid pore formation induced by fonticins. Baseline shows untreated cells of Pragia fontium 24647. Potassium efflux was measured using potassium-selective electrodes in a vessel containing 6 mL of cell suspension with OD₄₅₀ of 0.2. The maximum potassium efflux was achieved by disruption of all cells by sonication (lysed cells). The data were converted to parts per million. Before each measurement, the calibration of potassium-selective electrodes was measured using precisely defined amounts of KCl solution (0.1, 1, and 10 ppm). The data were aligned to zero by subtracting the initial baseline value. Original values of the baseline and lysed cells were 0.30 and 0.36 V of electrical potential, respectively. Representative results from three separate measurements are shown.