Fig. 1. Effect of glucose concentration on the rate and spectrum of mutations in E. coli strain K-12 MG1655 wild-type and ΔluxS deletant. (a) Spontaneous mutation rate to rifampicin resistance measured by the fluctuation test (mean±se from n=182 independent populations for each estimate). (b) Spectrum of spontaneous mutations in wild-type MG1655 and ΔluxS deletant under high and low glucose treatments, showing increased AT>GC transitions in low glucose for both strains (*χ12=5.44, P=0.020), elevated GC>TA transversions for the ΔluxS deletant (†χ12=5.21, P=0.022) and a greater frequency of indels in the wild-type MG1655 background (‡χ12=5.47, P=0.019). Note that relative frequencies are shown due to uneven sample sizes among treatments.
