Figure 2. Thiourea does not protect cells from the superoxide that is generated by a redox-cycling antibiotic.

Cells growing in aerobic glucose medium were treated with paraquat (PQ) starting at t=0. All cells (MG1655, KCI746) were SodB+; where indicated, strains lacked the inducible SodA superoxide dismutase, in order to establish that the growth defect arose from superoxide. (A) Thiourea (TU, 150 mM) was supplemented as indicated. (B) Parallel sodA cultures were supplemented with 10 mM glutathione (GSH), 10 mM N-acetylcysteine (NAC), 0.1 mM edaravone (Eda), 10 mM Tiron, or 5 mM ascorbate (Asc).