Fig. 3.

Dose response curves of potassium bromate, benzo[a]pyrene plus visible light and 4-nitroquinoline-1-oxide (4-NQO). Closed black circles, Salmonella typhimurium TA1535; closed red circles, YG3001 (same as TA1535 but ΔmutM); closed black squares, TA1975 (same as TA1535 but uvrB⁺); closed red squares YG3003 (same as TA1975 but ΔmutM). When the mutagenicity of benzo[a]pyrene in the presence of visible light, plates were exposed to fluorescent light 15 W lamps at a distance of 30 cm during incubation at 37°C for two to three days. The data are from references (63,64).