Figure 2.
Effect of antioxidants on UVA- and UVB-induced early mutagenesis. Cells were exposed to 321 kJ/m2 UVA- (A) or 8.1 kJ/m2 UVB radiation (B). The cells were grown with or without antioxidants in ordinary medium for 8 days after ultraviolet irradiation. Subsequently, the cells were seeded in medium containing 5 μg/ml 6-thioguanine and no antioxidants. 0: medium without antioxidants, CAT: catalase, GSH: glutathione, SOD: superoxide dismutase. Error bars = standard error from 3–10 independent experiments each with 3–4 parallel dishes. *: significantly different from unirradiated cells (Mann-Whitney rank sum test, p < 0.05). ◆: significantly different from cells not treated with antioxidants (Mann-Whitney rank sum test, p < 0.05). Mutant frequency = number of mutant colonies per million cells seeded.