Figure 2.

Initial rates of iron accumulation by C. velia and S. cerevisiae. C. velia was grown in iron-rich (1 μm; black squares) or iron-limited (10 nm; white squares) Mf medium. S. cerevisiae was grown in iron-rich (1 μm; black circles) or in iron-deficient (white circles) medium. Cells were washed once with iron-free Mf medium containing 1 mm EDTA and twice with iron-free Mf medium (C. velia) or 50 mm citrate buffer (S. cerevisiae), and resuspended in the same final media at 100 × 10⁶ cells/mL. For yeast, 2% Glc was added to the citrate buffer. Cells were incubated in the light at 25°C or 30°C, respectively, in the presence of 1 μm ⁵⁵Fe(III)-citrate (1:20). Aliquots were taken at intervals and washed three times with Mf medium containing 1 mm EDTA before counting. Means ± sd from six experiments are given.