Sterol manipulation that modulates the alteration in membrane fluidity of Tetrahymena pyriformis during temperature acclimation.
Our previous results [Umeki and Nozawa (1983) Biochem. Biophys. Res. Commun. 113, 96-101] suggested that ergosterol-replaced Tetrahymena cells (ergosterol-cells) accomplish an adaptive modification of fatty-acid composition by a preferential increase in palmitoyl-CoA desaturase activity, which is principally due to the increased content of the terminal component (cyanide-sensitive factor) of the desaturase system. The present study was designed to obtain information as to how the membrane fluidity of ergosterol-cells is changed during cold temperature acclimation. The order parameter (S) of liposomes prepared from ergosterol-cell lipids was reduced more rapidly after a temperature shift-down than that of control liposomes prepared from native cells containing tetrahymanol. These results indicate that, unlike native cells containing tetrahymanol, ergosterol-cells strive to accomplish cold temperature acclimation by undergoing a great modification of membrane fluidity because of the altered microsomal desaturase activity.
D000064:Acclimatization; D000214:Acyl Coenzyme A / Q000378:metabolism; D000818:Animals; D004875:Ergosterol / Q000378:metabolism*; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000502:physiology*; D008861:Microsomes / Q000378:metabolism; D013696:Temperature; D013769:Tetrahymena pyriformis / Q000502:physiology*
D000214:Acyl Coenzyme A; D005227:Fatty Acids; D008563:Membrane Lipids; D044943:Fatty Acid Desaturases; D004875:Ergosterol