Characterizations of Pneumocystis carinii and rat lung lipids: glyceryl ethers and fatty alcohols

Pneumocystis carinii carinii and rat lung phospho- lipids contained 3-6% 1-alkyl-2-acyl glycerols composed of the glyceryl ether species, 1-O-octadecyl glycerol (batyl alco- hol), 1-O-octadec-9-enyl glycerol (selachyl alcohol), 1-O- hexadecyl glycerol (chimyl alcohol), and 1-O-hexadec-9-enyl glycerol. Of the major phospholipid classes, phosphatidyl- inositol (PI) and phosphatidylserine contained the highest percentage of alkyl acyl glycerols. Methylprednisolone treat- ment caused an increase in alkyl acyl PI of rat lung lipids from 12% to 45%. As the PI concentration in lung phospho- lipids increases in rats treated with methylprednisolone, the increase in alkyl acyl PI was substantial; the proportions of alkyl acyl phosphatidylethanolamine and alkyl acyl lyso phosphatidylcholine (PC) also increased. Pneumocystis phos- pholipids contained higher proportions of alkyl acyl PC than the phospholipids of the lungs from normal and im- munosuppressed uninfected rats. The glyceryl ether compositions of P. carinii carinii PC and lyso PC were simi- lar, which suggests that lyso PC in the organism is derived by phospholipase A 2 action on PC. This was not the case for PC and lyso PC of the lung controls. Analysis of the free fatty alcohols, precursors of glyceryl ethers identified only saturated species in P. carinii carinii and rat lung controls. Thus, the introduction of a double bond in the alcohol moi- ety of glyceryl ethers occurs after formation of the ether linkage between fatty alcohol and the glyceryl backbone.— Kaneshiro, E. S., Z. Guo, D. Sul, K. A. Kallam, K. Jayasim- hulu, and D. H. Beach. Characterization of Pneumocystis car- inii and rat lung lipids: glyceryl ethers and fatty alcohols. J. Lipid. Res. 1998. 39: 1907-1917.