Figure 3
The effects of amino acid composition on transition of wild type and relaxed BW25113 E. coli strains from stationary phase to new exponential growth.
After 15 hours in the stationary phase in M9 medium supplemented with 0.4% glucose, cells were gently pelleted, washed with M9 and diluted into fresh M9 medium supplemented with either 19 amino acids (A–C) or with one amino acid (D–F). Omitted (A–C) or added (D–F) amino acids are indicated by standard three-letter abbreviations with colours grouping amino acids to their biosynthesis pathways as per Keseler and colleagues55 with an exception of grey symbols for Arg, Pro and His which are synthesized via unrelated ad hoc pathways. Empty symbols designate the M9 medium without the addition of any amino acids. Growth resumption was followed for E. coli wild type (A,D) and ΔrelA (B,E) cultures. The ratio of OD600 for ΔrelA to OD600 of the wild type strain (C,F) serves as a numerical measure of the difference in growth resumption kinetics between the two. The results are shown as mean values of biological replicates (n ≥ 3). The error bars (too small to be seen for some of the points) indicate standard error of the mean and for the sake of clarity are omitted on traces lacking specific effects.
