Changes in fatty acid distribution and thermotropic properties of phospholipids following phosphatidylcholine depletion in a choline-requiring mutant of Neurospora crassa.
Growth of a choline requiring auxotroph of Neurospora crassa on medium lacking exogenous choline produces large changes in the levels of phosphatidylethanolamine and phosphatidylcholine. Whole cell fatty acid distributions were found to vary widely between different phospholipid species of normally growing, choline-supplemented cultures with phosphatidylcholine showing the highest levels of unsaturation and anionic phospholipids and cardiolipin having the lowest. In these lipids, choline deprivation produced little change in fatty acid profiles of phosphatidylethanolamine, whereas changes in fatty acids of phosphatidylcholine and acidic phospholipids resulted in increased levels of unsaturation at both growth temperatures. Microsomal phospholipids also showed fatty acid variability with sharp decreases in phosphatidylcholine unsaturates and increases in acidic phospholipid unsaturated fatty acids at low growth temperatures. Fluorescence polarization of 1,6-diphenylhexatriene in vesicles formed from total cellular and microsomal lipids showed that choline deprivation produces changes in thermotropic properties in the lipids in deprived cultures at either growth temperature. The effective differences in fluorescence polarization between choline-deprived and supplemented cultures grown at a given temperature were found to be comparable to those produced by temperature were found to be comparable to those produced by temperature acclimation in normally growing cultures over a temperature range of 22 K.
D002794:Choline; D005227:Fatty Acids / Q000378:metabolism*; D008433:Mathematics; D008560:Membrane Fluidity; D009154:Mutation; D009492:Neurospora crassa / Q000235:genetics / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism; D010743:Phospholipids / Q000032:analysis*; D013696:Temperature
D005227:Fatty Acids; D010713:Phosphatidylcholines; D010743:Phospholipids; D002794:Choline