Fig. 3. (a) Effect of substrate incubation time on fluorescence of E. coli cells expressing MAO-N D5 stained with 50 μM C-H₂DCFDA and incubated with AMBA, compared to a non-induced control. (b) Effect of probe concentration on the maximum fluorescence of E. coli cells stained with C-H₂DCFDA determined by the addition of 10 mM H₂O₂ (blue line) prior to analysis, in comparison to the fluorescence of C-H₂DCFDA stained cells after incubation with AMBA for 5 (red line) and 20 (green line) minutes.