Fig. 3
Ferrireductase activity and iron uptake activities of O. tauri and C. reinhardtii. O. tauri and C. reinhardtii cells were grown for one week in their respective standard media (see Methods), washed once in iron-free medium and they were then used to inoculate Mf (O. tauri) or modified TAP medium (C. reinhardtii) with either no added iron (open symbols) or with the addition of 5 μM Fe(III)-citrate (closed symbols). Cells were harvested at intervals, and ferrireductase activity (A) and iron uptake activities (B, C) were determined. a Ferrireductase activity was measured as described in the methods. Circles: O. tauri; squares: C. reinhardtii. Values are expressed in pmole/h/mm2 of cell surface to facilitate comparison (see in Methods). b Iron uptake by O. tauri cells, measured with either 1 μM Fe(II)-ascorbate (1:1000) (squares) or 1 μM Fe(III)-EDTA (1:5) (circles). c Iron uptake by C. reinhardtii cells, measured with either 1 μM Fe(II)-ascorbate (1:1000) (squares) or 1 μM Fe(III)-EDTA (1:5) (circles). Means ± SD from 3 experiments