ADAPTATIONS TO TEMPERATURE IN THE CELLULAR MEMBRANES OF CRUSTACEA - MEMBRANE-STRUCTURE AND METABOLISM

1. 1.|Acute changes in environmental temperature have deleterious effects on the structure and function of cellular membranes of crustaceans, as well as other poikilothermic animals. Low temperature increases membrane order, and decreases "fluidity", in addition to influencing the activity of membrane-bound enzymes. 2. 2.|Crustaceans adapt to prolonged exposure to low temperatures by increasing the fluidity of membrane lipids, which serves to restore membrane function. 3. 3.|Membrane fluidity is regulated by changing the proportions of saturated and unsaturated fatty acids on membrane phosphatides at different temperatures. Unsaturation increases at low temperatures. 4. 4.|The proportion of different phospholipid head groups also changes in response to temperature, particularly among winter-active crustaceans. Ethanolamine phosphatides increase at the expense of choline phosphatides at low temperatures. 5. 5.|The experimental evidence for various metabolic mechanisms of membrane restructuring in crustaceans is discussed. © 1990.