FIG. 4.

Effect of NO on growing cells of Synechocystis. (A) Paper disks soaked with water (1) or 5 μl (2) or 15 μl (3) of a 0.5 mM SNP solution were placed on agar plates spread with a layer of Synechocystis cells. Left plate, mutant M321; right plate, wild type. Inhibition zones occurred after incubation for 36 h. (B) Suspensions of Synechocystis cells in BG-11 medium containing 0.6% agar were grown in glass tubes sealed with a rubber septum. WT, wild type; M320 and M321, norB-negative mutant strains. NO gas (10 mM) was injected before incubation (+NO).