Characterization of cytochrome c accumulation in white and pink strains ofUstilago violacea using low-temperature spectroscopy and amino acid analysis

The extent of cytochrome c accumulation in 46 pink and white strains ofUstilago violacea was determined using low-temperature spectroscopy. Pink strains accumulated approximately 14 times more cytochrome c than white strains. Cytochrome c was extracted and purified from two pink (2A2, 1.C429) and two white (15.10, 900-42.1) strains ofU. violacea and subjected to amino acid analysis. One pink (2A2) and one white (15.10) strain were genetically related; the others (900-42.1, 1.C429) were not. One white strain (900-42.1) contained spectrally distinct cytochrome c. Comparisons of the amino acid compositions of the cytochrome c from these four strains ofU. violacea using divergence calculations and computer-assisted cluster analysis indicated a high degree of relatedness for the two pink strains, a moderate degree of relatedness for the pink strains and white strain 15.10, and a low degree of relatedness for white strain 900-42.1 with the others. These results support the hypothesis that there are two distinct cytochrome c loci inU. violacea.