CHARACTERIZATIONS OF NEUTRAL LIPID FATTY-ACIDS AND CIS-9,10-EPOXY OCTADECANOIC ACID IN PNEUMOCYSTIS-CARINII CARINII

Pneumocystis carinii causes pneumonitis in immunodeficient individuals and is a prevalent opportunistic infection of patients with AIDS, Thi s pathogen resides extracellularly in the hypophase lining the alveola r epithelium, which is highly enriched in lung surfactant lipids, Proc edures yielding highly pure organism preparations that enable reliable biochemical analyses of organisms isolated from the lungs of infected laboratory animals have been developed, The results of the present st udy revealed that the fatty acid profiles of total lipids, the neutral lipid fraction, and individual neutral lipid classes of lungs from no rmal and immunosuppressed rats as well as P. carinii were grossly simi lar, although some quantitative differences were detected, One qualita tive exception found was the detection in P. carinii of the rare fatty acid cis-9,10-epoxy stearic acid, which was not detected in the lipid s of rat lungs, The detection of this fatty acid in P. carinii may als o have important taxonomic implications, Unlike phospholipids, many of the fatty acids of nonmembrane neutral lipids may be utilized by P. c arinii for other cellular functions, such as stored reserves for energ y production and precursors for organism-specific membrane lipids, The present study represents the first report of detailed fatty acid anal yses of individual neutral lipid classes of this important opportunist ic pathogen.