Fig. S2.

Kinetics of ⁵⁵Fe incorporation from ⁵⁵Fe(III) citrate into O. tauri growing cells. ⁵⁵Fe(III) citrate (1 µM) was added to cultures of O. tauri inoculated at 10 × 10⁶ cells/mL at day 1 after 24 h of culture. Cell growth was monitored by flow cytometry for 1 wk (black circles). The amount of intracellular iron was quantified by scintillation counting after the cells were washed twice with an oxalate/EDTA buffer. The cell cultures reached stationary phase (70 × 10⁶ cells/mL) after 4 to 5 d. After 5 d in culture, more than 99% of added Fe(III) citrate had been incorporated by the cells (red squares). Data shown are the mean of two independent experiments.