Effects of growth temperature on the fatty acid composition of the free-living nematodeCaenorhabditis elegans

The effects of growth temperature on the fatty acid compositions of the phosphatidylcholine (PC), phosphatidylethanolamine (PE), and total lipid (TL) fractions of the free-living nematodeCaenorhabditis elegans were investigated. A reduction in growth temperature from 25 to 15°C caused the proportions of eicosapentaenoic acid (20∶5n-3) to increase from 23.6 to 32.5% in the PC, from 7.4 to 10.8% in the PE, and from 12.9 to 19.9% in the TL fractions. Conversely, the levels of dihomo-γ-linolenic acid (20∶3n-6) and arachidonic acid (20∶4n-6) in these phospholipid fractions and the TL fraction both decreased with decreasing growth temperature. Analysis of the positional distribution of fatty acids in the PC fraction revealed that the change in the composition of C₂₀ polyunsaturated fatty acid was obvious in positionsn-2. Lowering the growth temperature induced an increase in the level of the diacyl subclass of PE from 58% at 25°C to 71% at 15°C, with a concomitant decrease in the levels of the alkylacyl and alkenylacyl subclass of PE ofC. elegans. These changes observed in the phospholipids ofC. elegans might be one mechanism for adaptation to low temperature. Lipids 31, 1173–1178 (1996).