Figure 4. Effects of glpR overexpression on the appearance of Glp⁺ mutants in a crp glpR genetic background when cells were grown on LB agar plates without glycerol (A) or on minimal M9 plates plus glycerol (B).

glpR expression in pBAD24 was induced by adding L-arabinose and IAA (inducers) to the media at 1 mM and 0.5 mM final concentrations, respectively. For the LB agar plate assay, ~100 cells were applied onto each plate. After incubation at 30°C for two days, individual colonies were examined for total and Glp⁺ cell populations. For the M9 + glycerol plate assay, Glp⁺ mutations and total populations were determined as described in Methods.