The net light-induced O2 evolution rate Pobs
(A), dark respiration rate R (B) and the adjusted O2 evolution rate Padj
(C) of the ΔAB cells dropped gradually after glucose deprivation (time constant ca. 8 h). The exponentially grown cells were harvested, washed and re-suspended in fresh BG-11 medium without glucose and kept at 30°C and under 1 µmol photons·m−2s−1 light prior to experiments. A final concentration of 10 mM NaHCO3 was added before each measurement. For each panel, data from 3 independent experiments were normalized to the maximal rate (right before glucose deprivation) and combined. For each rate, 100% activity is the activity before the sample was deprived of glucose. (D) Recovery of the net light-induced O2 evolution rate (Pobs) (closed circles) and the dark respiration rate (R) (open circles) after glucose (5 mM) was supplied to the 42 h glucose-depleted ΔAB cells. Since 5 mM glucose was enough to maintain cell growth until stationary phase, the remaining glucose concentration during/after the measurements was assumed to be sufficient.