Two groups of fruit flies (Drosophila melanogaster) were maintained on different diets. Mitochondria were isolated, proton leak was measured and phospholipid fatty acid composition determined. Mitochondria from flies fed on corn-base meal (containing high amounts of polyunsaturated fatty acids, 18:2(n-6) and 18:3(n-3) and low amounts of monounsaturated fatty acid, 18:1(n-9)) contained more poly...