Quinone systems and cellular fatty acid composition in species of Rhodospirillaceae genera.

Forty nine strains of 12 species of purple nonsulfur phototrophic bacteria (Rhodospirillaceae) and one strain of facultatively methylotrophic bacteria, Protomonas extorquens were investigated with regard to their quinone systems and cellular fatty acid composition. These bacteria had the ubiquinone systems. Some strains had in addition a small amount of menaquinone system, which had the same isoprenoid chain length as the major ubiquinones. The strains in the genera Rhodobacter, Rhodomicrobium, Rhodospirillum, Rhodopseudomonas except for Rhodopseudomonas viridis, and Protomonas extorquens had Q-10 as a major component. Out of the above mentioned strains, the strains of Rhodopseudomonas acidophila also had MK-10 concurrently. The strains of Rhodopila globiformis and Rhodopseudomonas viridis had Q-9 and MK-9. Most of the Rhodocyclus gelatinosus strains had Q-8 and MK-8. The strains of Rhodocyclus gelatinosus contained large amounts of C16:0 acid and C16:1 acid. The strains in the genera Rhodopseudomonas except for Rhodopseudomonas acidophila, Rhodomicrobium, Rhodobacter, and Rhodopila, and in Protomonas extorquens, contained a large amount of C18:1 acid. The strains of Rhodospirillum rubrum, and Rhodopseudomonas acidophila contained large amounts of C16:0 acid, C16:1 acid, and C18:1 acid. Based on these results along with information on other taxonomic properties such as morphology and phylogeny, the relationship of the facultatively methylotrophic bacterium Protomonas extorquens to the species of Rhodospirillaceae genera is discussed.