Regulation of membrane lipid fluidity in Acholeplasma laidlawii: effect of carotenoid pigment content.

摘要: Abstract Acholeplasma laidlawii (oral strain) cells were grown in a lipid-extracted medium supplemented with arachidic acid (C20:0). The carotenoid content of the plasma membrane was appreciably dependent upon levels acetate or propionate present growth medium. 1. Membranes isolated from (5 g/l) contained low level carotenoids, approximately 11 wt% total lipids. Neither fatty acyl composition nor lipid/protein ratio altered. However, spin-labelling experiments demonstrated greater lipid fluidity those membranes, as compared to an containing characterized by higher buoyant density, osmotic fragility and lower glycerol permeability. 2. Growing 20 g/l instead acetate, decreased 57-fold. For (20 g/l), high pigments (about 38 lipids) obtained; fewer arachidoyl more unsaturated groups found Spin-labelling showed only very slight difference between two types membrane. 3. These results suggest that rigidify organism maintains its within narrow range modifying