FIG 2.

Measurement of Cu⁺ production. Iron coupons were incubated with cell suspensions containing 4 mM CuSO₄ under either aerobic (●) or anaerobic (○) conditions. At the times indicated, samples were withdrawn, and the Cu⁺ formed was complexed with BCA, followed by spectrophotometric determination of Cu⁺ as described in Materials and Methods. The error bars indicate the standard deviations of three independent experiments.