Cellular redox status during growth of M. smegmatis mc2155 (A) and M. smegmatis mshD::Tn5 (B). •, A600; ▾, MSH; ♦, Cys; ○, fCys-GlcN-Ins; □, succ-Cys-GlcN-Ins; ▪, Cys-GlcN-Ins. Results from two independent cultures are shown. The average deviation from the mean was ≤30%, except for the results shown in panel B, where the average deviation was 45% for MSH and 55% for succ-Cys-GlcN-Ins.