Figure 4.

The time course of ⁵⁵Fe³⁺ ferrichrome uptake for mtsA (open circles), ftsB (open triangles), and ftsC (solid triangles) mutant and wild-type (solid circles) GAS strains. Each strain harvested at the mid-exponential growth phase from 40 ml culture, washed with 10 ml of THY, and incubated with 0.16 μM ⁵⁵Fe³⁺ ferrichrome in 4 ml of THY at room temperature. A triplet of 0.2 ml samples were taken from each mixture at the indicated times, and bacteria were immediately pelleted and washed twice with 0.4 ml of THY. Presented are the mean values ± SD of ⁵⁵Fe³⁺ radioactivity associated with the bacteria in a representative of three experiments.