Incorporation of a naturally occurring fluorescent fatty acid into lipids of cultured mammalian cells.

A fluorescent fatty acid, cis-parinaric acid (cis-PnA), has been biosynthetically incorporated by cultured mammalian cells. The fatty acid probe is predominantly incorporated into phospholipids, with a small amount of incorporation into the neutral lipid fraction. Both phosphatidylethanolamine and phosphatidylcholine are labeled with the fluorescent probe. The temperature dependence of the fluorescence intensity of cis-PnA, either biosynthetically incorporated or added as the free fatty acid, suggests thermally induced structural reorganizations in phospholipids isolated from cultured cells enriched in palmitic acid. Results are essentially identical with both forms of the probe.