title: Temperature-induced membrane-lipid adaptation in Acanthamoeba castellanii.
abstract: A method has been developed for the separation of the major membrane fractions of Acanthamoeba castellanii after growth at different temperatures. The acyl-lipid compositions of individual membrane fractions, microsomal membranes, plasma membrane and mitochondria were analysed after a shift in culture temperature from 30 degrees C to 15 degrees C. The major change in lipid composition observed was an alteration in the relative proportions of oleate and linoleate. This reciprocal change was seen in all the membrane fractions, but occurred most rapidly in the phosphatidylcholine of the microsomal fraction. Thus, there appears to be a rapid induction of delta 12-desaturase activity in A. castellanii after a downward shift in growth temperature. Changes were also seen in the proportions of the n-6 C20 fatty acids, with a decrease in the proportions of icosadienoate and increases of icosatrienoate and arachidonate. However, unlike the alteration in oleate/linoleate ratios, this change was not seen in all the individual lipids of each membrane fraction.
authors.affiliation: Department of Biochemistry, University of Wales College of Cardiff, U.K.
authors.forename: A L
authors.initials: AL
authors.lastname: Jones
authors.forename: A C
authors.initials: AC
authors.lastname: Hann
authors.forename: J L
authors.initials: JL
authors.lastname: Harwood
authors.forename: D
authors.initials: D
authors.lastname: Lloyd
mesh_terms: D000048:Acanthamoeba / Q000378:metabolism*; D000222:Adaptation, Physiological; D000818:Animals; D002458:Cell Fractionation; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000648:ultrastructure; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis / Q000378:metabolism; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism; D008563:Membrane Lipids / Q000032:analysis / Q000378:metabolism*; D008861:Microsomes / Q000648:ultrastructure; D008928:Mitochondria / Q000648:ultrastructure; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D010713:Phosphatidylcholines / Q000032:analysis / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000032:analysis / Q000378:metabolism; D013696:Temperature
chemical_list: D005227:Fatty Acids; D008041:Linoleic Acids; D008563:Membrane Lipids; D009829:Oleic Acids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D019301:Oleic Acid; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; C040448:delta-12 fatty acid desaturase