title: The fluidity of plasma membranes of Dictyostelium discoideum. The effects of polyunsaturated fatty acid incorporation assessed by fluorescence depolarization and electron paramagnetic resonance.
abstract: Two probe techniques, fluorescence depolarization (using diphenylhexatriene) and electron paramagnetic resonance (using 5-doxyl stearic acid), have been used to assess the fluidity of the purified plasma membranes of Dictyostelium discoideum. Both techniques indicate that a large incorporation of polyunsaturated fatty acids into the plasma membranes does not significantly change membrane fluidity In addition, phosphatidylcholines isolated from cells grown on both polyunsaturated fatty acid-supplemented and unsupplemented media exhibit similar mobilities of an incorporated spin probe when dispersed in aqueous solution. This result suggests that the enrichment of a membrane already high in content of fatty acyl chains containing two double bonds with those containing three or more double bonds does not markedly change fluidity.
mesh_terms: D002462:Cell Membrane / Q000502:physiology; D003497:Cyclic N-Oxides / Q000032:analysis; D004023:Dictyostelium / Q000502:physiology*; D004161:Diphenylhexatriene / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes / Q000494:pharmacology; D008560:Membrane Fluidity / Q000187:drug effects*; D010713:Phosphatidylcholines / Q000032:analysis; D010743:Phospholipids / Q000032:analysis; D011090:Polyenes / Q000494:pharmacology*; D013229:Stearic Acids / Q000032:analysis
chemical_list: D003497:Cyclic N-Oxides; D005231:Fatty Acids, Unsaturated; D005456:Fluorescent Dyes; D010713:Phosphatidylcholines; D010743:Phospholipids; D011090:Polyenes; D013229:Stearic Acids; D004161:Diphenylhexatriene; C005072:5-doxylstearic acid