TEMPERATURE-ACCLIMATION OF MARINE CRABS - CHANGES IN PLASMA-MEMBRANE FLUIDITY AND LIPID-COMPOSITION

1. Crabs were acclimated for 3 weeks to cold and warm temperatures. Pl asma membranes prepared from leg muscle were analysed for fluidity and lipid composition. 2. Plasma membranes from cold-acclimated crabs wer e more fluid and had lower cholesterol to phospholipid ratios than tho se from warm-acclimated crabs. The ratio saturated/unsaturated fatty a cids was little altered by temperature acclimation. 3. Plasma membrane s from the stenothermal species (Cancer pagurus) were slightly more fl uid (at DPH probe level) and had lower cholesterol/phospholipid ratios than those from the eurythermal species (Carcinus maenas). 4. Plasma membranes from crabs acclimated in spring had more saturated and less polyunsaturated fatty acids than those from crabs acclimated in autumn .