Fatty acids of membrane phospholipids in Drosophila melanogaster lines showing rapid and slow recovery from chill coma.

We investigated the fatty acid compositions of phospholipids in Drosophila melanogaster lines showing rapid (CR), intermediate (CTL), or slow (CS) recovery from chill coma, which were established by artificial selection or by free recombination without selection. Compared to CTL, CS showed a low composition of dienoic acids and a small number of double bonds in the fatty acids. The ratio of unsaturated fatty acids and saturated fatty acids (UFAs/SFAs) was significantly lower in CS than in CTL. CR had higher monoenoic acid composition and lower dienoic acid composition than CTL. In addition, the amount of SFAs was lower and therefore the UFAs/SFAs ratio considerably higher in CR than in CTL. These changes in phospholipid fatty acids probably contributed to losing and maintaining the homeoviscosity of the cellular membranes in CS and CR, respectively, at low temperature and therefore produced their distinct phenotypes in recovery from chill coma.