FIG 2.

Arginine decarboxylase assay. RpoC modulates arginine-dependent pH rise in strain B11-1 but not in strains F9-2 and H9-1. Unique rpo point mutations found in the acid-evolved strains were reverted to represent the original ancestral W3110 sequence for strain B11-1 (A) as well as strains H9-1 and F9-2 (B). The method described in the legend of Fig. 1B was modified for kinetic recording of absorbance ratios. Absorbance readings were taken every 2 h for 48 h. Replicates for each strain are shown as curves of the same color.