Figure 6

Estimation of the expression of cytochromes in mixotrophically growing cells. The expression of cytochromes was determined under the following cultivation conditions, which allowed a high expression of photosynthetic pigments and mixotrophic growth in the respective strains: L. syltensis DSM 22749^T was cultured in SYMHC medium under air atmosphere (red line), C. halotolerans DSM 23344^T (blue line) and P. rubra DSM 19751^T (green line) in defined medium containing 10 mM DL-malate at an initial head space gas atmosphere of 20% (v/v) O₂. The position of distinct peaks of the spectra is indicated. A.U., arbitrary units of absorbance. A. Dithionite-reduced minus ferricyanide-oxidized redox difference spectra of extracts from whole cells solubilized with 0.3% (w/v) N,N-dimethyldodecylamine-N-oxide. Peaks at 424 and 553 nm indicate the presence of cytochrome c and the peak around 602 nm cytochrome a; shoulders in the Soret region at 434 and 445 nm the presence of cytochromes b and a, respectively. B. CO and dithionite-reduced minus dithionite-reduced difference spectra of intact cells. Troughs in the Soret region at 433 and 446 nm could indicate the binding of CO by heme b and aa₃, respectively.