Figure 1.

Nitrogen starvation conditions for Synechocystis sp. PCC 6803. (A) Schematic representation of the experimental procedure to capture the early acclimation to the nitrogen starvation examined by RNA-seq and ChIP-seq in this study, before prolonged starvation leads to chlorosis. (B) In situ analysis of GS activity from Synechocystis cells growing in BG11C+NH₄ or after incubation for 4 h in nitrogen-free BG11C medium. A sample of 1 ml of Synechocystis culture was used for each assay. Transferase activity was measured after 5 min of incubation. Activity measures represent arithmetic means of three independent experiments, and their standard deviation values. C, control without adding cells. (C) Image of Synechocystis cultures used for RNA-seq and ChIP-seq experiments, after growing in either BG11C+NH₄ or nitrogen-free BG11C medium for 24 h.