Figure 1.

Growth, NDH-CET activity, and transposon insertion site of high-light-sensitive mutants of Synechocystis 6803. A, Growth of the wild type (WT) and mutants under normal light (40 µmol photons m⁻² s⁻¹) and high light (200 µmol photons m⁻² s⁻¹). B, Analysis of NDH-CET activity using Chl fluorescence. The top curve shows a typical trace of Chl fluorescence in wild-type Synechocystis 6803. The Chl a concentration was adjusted to 10 µg mL⁻¹ before measurement. Cells were exposed to actinic light (AL; 620 nm, 45 µmol photons m⁻² s⁻¹) for 30 s. AL was turned off, and the subsequent change in the Chl fluorescence level was recoded. The activity of NDH-CET in the wild type and mutants was compared from the height and the relative rate of postillumination increase in Chl fluorescence. C, Schematic with the arrow indicating the transposon insertion site in mutants 1 and 2 probed by PCR analysis using the primers listed in Supplemental Table S1.