A method for 13C enrichment of phospholipid acyl chains using Tetrahymena

A method has been devised for obtaining highly 13C enriched (20-25%) phospholipids and membranes from the ciliate Tetrahymena, the enrichment occurring in the acyl chains. This method provides both phosphatidylcholine and phosphatidylethanolamine with enriched chains. The central feature of the method is the monoaxenic growth of Tetrahymena on an E. coli mutant which has a high incorporation of exogenous acetate into fatty acid chains. The 13C NMR spectra of the phospholipids are sufficiently enriched to permit NMR relaxation studies.