Figure 4
Growth on glucose and a poor nitrogen sources can be improved by increasing cAMP levels by genetic means or external supplement.
(a) Different mutant strains with glucose as a carbon source (0.2%) and arginine (10 mM) as a nitrogen source. Reporter concentration (GFP/OD) and growth rate (hr−1) were determined for the same time window at mid exponential phase. Each point is the average of 3 independent experiments with 6 experimental replicates in each experiment. Due to very low GFP levels for the ΔcyaA strain promoter activity was very noisy and we therefore show GFP per OD unit instead of promoter activity (b) Exponential growth rate of NCM3722 strain in glucose (0.2%), with different nitrogen sources (18.7 mM ammonia or 10 mM of the amino acids) and externally added cAMP in the indicated levels, normalized to growth rate in the absence of cAMP. Growth rate in each condition is the average of 2–4 independent experiments on different days with 6 experimental replicates in each experiment. Error bars are the standard deviation of biological repeats.
