COMPARISON OF LIPID COMPOSITION OF PLEUROPNEUMONIA-LIKE AND L-TYPE ORGANISMS

Abstract

The content of total lipid and nonsaponifiable lipid depended upon the type of organism; the greatest amounts were found in pleuropneumonia-like organisms that required cholesterol for growth and in L-1, the L-form of Streptobacillus moniliformis. Decreasing amounts were found in nonsterol-requiring strains of pleuropneumonia-like organisms, the stable L-form of Proteus, salt-requiring L-forms, and finally, the bacterial parents of the L-type organisms. Nonsterol-requiring pleuropneumonia-like organisms could synthesize their own nonsaponifiable lipid, but sterol-requiring strains could not. Ability or inability to synthesize nonsaponifiable lipid was often carried over to the L-type organisms from the bacterial parent. More nonsaponifiable lipid was found in the sedimentable fraction (cell membrane) than in the nonsedimentable fraction (protoplasm) of both pleuropneumonia-like and L-type organisms. None of the nonsaponifiable lipid synthesized by any organism tested appeared to be 3-[beta]-hydroxy sterol. Differences in ability of various organisms to take up cholesterol and to be lysed by digitonin were established.