FIG 5.
Antibiotics and iron chelation induce excessive iron accumulation. E. coli CP9 was cultured in BHI medium in the presence or absence of an antibiotic (VAN at 250 μg/ml, CTX at 62.5 ng/ml, or LVX at 0.01 μg/ml), DFP (150 μg/ml), or both. After 18 h, the amount of iron present in the cell pellet (A), calculated as the number of iron atoms per cell, or the total iron present in the sample (B) (Fesupernatant plus Fecell pellet), was determined by ICP-OES. The data in panel A were normalized to the level of iron present in untreated cells (left columns). Data are the mean values and standard deviations from three independent experiments. P values were determined by Student's t test.