Fig. 2. Response of SOD activity to experimental hyperoxia. (A) SOD activity of the three separated compartments of A. viridis (Ec, ectoderm; Ed, endoderm; FIZ, freshly isolated zooxanthellae). (B) Total extract of A. schmidti in two conditions: control (C; air saturated) and hyperoxia (H_,; O₂-saturated seawater), revealed by native PAGE (8%) and NBT staining, either without KCN (–KCN) or with (+). Arrows indicate pharmacological identification of bands: MnSOD (black arrows), CuZnSOD (open arrows) and FeSOD (grey arrows). (d) Corresponds to an O₂-induced SOD isoform (AsSODd). Cytosolic fractions containing a quantity of 150 µg of protein was loaded in each well. These patterns were reproducible in four independent experiments for each species.