Accumulation of reactive oxygen species in E. coli treated with oxolinic acid with or without resveratrol.

Exponentially growing E. coli cultures (~ 2.5 X 10⁸ cells/ml) were treated with 10 μM carboxy-H₂DCFDA for 20 min before cells were administered oxolinic acid alone (WT + Oxo; 20 X MIC, 8 μg/ml), resveratrol alone (WT + Res; 0.5 X MIC, 200 μg/ml), or oxolinic acid plus resveratrol (WT + Res + Oxo) for an additional 120 min. Samples taken before (A) and after (B) oxolinic acid treatment were subjected to flow cytometry analysis. Similar results were observed with 3 replicate experiments. Legend: Control samples (WT), black lines; resveratrol alone (WT + Res), green lines; oxolinic acid alone (WT + Oxo), red lines; and resveratrol plus oxolinic acid (WT+ Res + Oxo), blue lines.