Polyunsaturated fatty acids in neutral lipids and phospholipids of some freshwater insects

Citation

Ghioni C, Bell JG & Sargent JR (1996) Polyunsaturated fatty acids in neutral lipids and phospholipids of some freshwater insects. Comparative Biochemistry and Physiology - Part B: Biochemistry and Molecular Biology, 114 (2), pp. 161-170. https://doi.org/10.1016/0305-0491%2896%2900019-3

Abstract
The fatty acid compositions of total neutral lipids and total polar lipids from eight species of freshwater insects were determined: stonefly nymphs (Plecoptera), beetle larvae (Coleoptera), Chironomidae (Diptera), water boatmen (Corixidae and Notonecta; Heteroptera) and mayfly nymphs (Ecdyonurus venosus, Caenis, Ephemerella; Ephemeroptera). In addition, the compositions of individual phosphoglycerides were determined for four of the species (Plecoptera, Corixidae, Ecdyonurus venosus and Emphemerella). Saturated and monounsaturated fatty acids together represented up to 85% of the fatty acids of total neutral lipids with 16:0 (18-31%) being the most abundant saturated fatty acid and 16:1n-7 (10-28%), 18:1n-9 (6-12%) and 18:1n-7 (3-12%) the most abundant monounsaturates. Polyunsaturated fatty acids (PUFA) accounted for between 16% and 33% of the total fatty acids of neutral lipids, with 20:5n-3 (4-12%), 18:3n-3 (3-30%) and 18:2n-6 (1-8%) all being major components. Arachidonic acid, 20:4n-6 (0.4-1.0%) and 22:6n-3 were, respectivety, minor and insignificant components of total neutral lipids. PUFA were major fatty acids (34-56% of the total) in total polar lipids and in phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol. The major PUFA present were 20:5n-3 (14-27%) and 18:3n-3 (6-23%). The most abundant n-6 PUFA, especially in phosphoglycerides from Corixidae, was 18:2n-6 (3-11%). Arachidonic acid, 20:4n-6, was present in all phosphoglycerides accounting for 1-4% of the total fatty acids, except in the phosphatidylinositol of Corixidae where it accounted for 12% of the total. 22:6(n-3) was not present in significant amounts in any phosphoglyceride in any species. 18:1n-9 (8-20%) and 18:1n-7 (2-14%) were the most abundant monounsaturated fatty acids, especially in phosphatidylethanolamine. 16:0 was abundant in phosphatidylcholine (11-21%), and 18:0 (17-23%) was abundant in phosphatidylserine. The results are discussed in relation to the functions and origins of PUFA in freshwater insects.

Keywords
Freshwater; insects; lipids; phospholipids; polyunsaturated fatty acids

Journal
Comparative Biochemistry and Physiology - Part B: Biochemistry and Molecular Biology: Volume 114, Issue 2