Cellular fatty acid composition with special reference to the existence of hydroxy fatty acids, and the occurrence of squalene and sterols in species of Rhodospirillaceae genera and Erythrobacter longus.

Cellular fatty acids, squalene, and sterols in the bacteriochlorophyll-containing bacteria, which include Rhodospirillaceae genera, and Erythrobacter, were investigated. Hydroxy fatty acid composition, and the existence of squalene, Hop-22(29)-ene and Hopan-22-ol explained the heterogeneity of Rhodospirillaceae genera.Erythrobacter longus is distinguished from Rhodospirillaceae species on the basis of hydroxy fatty acid composition. Protomonas extorquens is similar to Rhodopseudomonas palustris and Rhodopseudomonas rutila on the basis of DNA base composition, the quinone system, cellular fatty acid composition, hydroxy fatty acid composition, and occurrence of Hop-22(29)-ene and Hopan-22-ol.