Oxidative stress tolerance of the wild-type
PCC7120 (WT) and An4641
. (A) Three-day-old Anabaena cultures were inoculated in a fresh growth medium and subjected to H2O2 (1 mM) stress for 2 days. Later, cultures were transferred onto a microtitre plates and photographed. (B) The chlorophyll a content of cultures shown in (A) was determined immediately (day 0) or after two days of exposure to H2O2. (C) Rapid light curves of ETR (II). Data were collected through the light response reaction from untreated (control cells) or cells treated with H2O2 (1 mM) as indicated in the figure. (D) The rate of 14CO2 fixation [μmoles of CO2 fixed (μg chlorophyll a)−1 h−1] of the wild-type Anabaena PCC7120 (WT) or An4641+ cells after treatment with 1 mM H2O2 for 24 h. (E) The wild-type Anabaena PCC7120 (WT) or An4641+ cells after treatment with H2O2 (1 mM) for 2 days were spotted (100 μl each) on BG-11 agar plate. The plates were incubated under continuous illumination and photographed after 14 days of incubation.