FIG. 3.

Complementation of the cya triple mutant with cyaA, cyaB, or cyaC. The mutant (□) was deficient in anaerobic respiration with DMSO (A), Fe(III) citrate (B), and fumarate (C). Introduction of cyaC (○) restored the ability of the triple mutant to grow with these electron acceptors. Introduction of cyaA (▵) led to wild-type levels of growth only when fumarate was used as the electron acceptor. Introduction of cyaB (*) into the mutant did not restore anaerobic respiration with any of the electron acceptors. The data are the means and standard deviations of three independent experiments. O.D. 600, optical density at 600 nm.