FIG. 1.

Impact of deletion of single c-type cytochrome genes on reduction of AQDS (left panels) and the Elliott soil humic acid standard (right panels) for strains with the (a) omcS, (b) omcE, (c) omcB, or (d) omcZ gene deleted. The rates of reduction for the mutant strains were compared with the rate of reduction for a batch of wild-type cells grown and analyzed simultaneously. Incubation was carried out with acetate as the electron donor and (in controls) without added acetate. The data are the means ± standard errors for triplicate incubations.