Variations des phospholipides au cours de la métamorphose de Tribolium confusum (Coléoptère)

The changing phospholipid pattern of the last instar larva and during metamorphosis has been studied by a new method. After extraction by the usual method of Folch et al. (1957), the total lipids were separated into polar and neutral fractions by a fixation technique on silicic acid. The phospholipids were subfractionated into classes and quantities estimated by thin-layer chromatography. Phosphatidylcholine and phosphatidylethanolamine were the major constitutents. Sphingomyelin was found in relatively high concentration but other constituents identified were lysophosphatidylcholine, lysophosphatidylethanolamine, phosphatidylserine, and cardiolipin. A relationship was found between this last group of compounds and oxygen consumption. The major changes were noted at the time of pupation and adult emergence. At the beginning of pupal period, a considerable amount of phosphatidylcholine is transformed into lysophosphatidylcholine. Reacylation of lysophosphatidylcholine to form phosphatidylcholine is suggested for the first time in an insect. There is a probability of phosphatide transfer between serine and phosphatidylethanolamine on adult emergence. The significance of these variations is discussed.