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The phospholipids ofCorynebacterium diphtheriae, Corynebacterium xerosis, Corynebacterium equi andCorynebacterium ovis were examined, largely by chromatographic procedures. In all of these, lipids of the phosphoinositide and mannophosphoinositide type were prominent. In contrast to the mycobacteria, the mannophosphoinositides of the corynebacteria were all dimannophosphoinositides; however, as in mycobacteria, these dimannophosphoinositides apparently occurred in the diacylated and triacylated forms—the tetraacylated component prominent in mycobacteria was absent. Phosphatidylethanolamine and phosphatidylserine were also absent. InCorynebacterium diphtheriae the major single phospholipid corresponded to phosphatidylglycerol: cardiolipin also appeared to be a major lipid. The fatty acids of the corynebacterial phospholipids were distinguished by the presence of branched chain isomers of medium chain length. The importance of phospholipids in the taxonomy of the actinomycetes and related eubacteria is discussed.

Assay of nonesterified fatty acids in 100 μ l. of serum is described. The fatty acids are extracted with chloroform-heptane-methanol solvent, and their copper complexes are determined by atomic absorption spectrophotometry. This technic possesses the sensitivity (20 μ moles per 1.) and reliability (4.2% coefficient of variation) required for clinical analyses, such as the response of serum nonesterified fatty acids to oral glucose challenge, while maintaining simplicity and ease of operation.