FIG 4.

Effect of δ-ALA supplementation on the cytochrome content, growth, and O₂ consumption. (A) UV/visible difference absorbance (ΔA) spectra were recorded in Salmonella grown in LB broth with or without 100 μM δ-ALA. The absorption band at 560 and the Soret peak at 430 nm correspond to the fully reduced cytochrome b. (B) Inner membrane preparations from fur mutant Salmonella grown with or without δ-ALA. (C, D) Effect of 100 μM δ-ALA on the growth of log-phase wild-type and fur mutant Salmonella in the presence of 2 mM DETA (C) or DETA NONOate (D). Where indicated, the Salmonella strains for which the results are presented in panels C and D were grown to log phase in LB broth supplemented with 100 μM δ-ALA. The cells were then washed and exposed to NO in fresh LB broth. (E) Effect of 100 μM δ-ALA on the respiratory activity of fur mutant Salmonella grown to log phase in EG medium. Selected cultures were treated with 5 μM proli NONOate (arrows) when the concentration of O₂ in the cultures reached about 130 μM.