In vitro and in vivo [ 14C]acetate incorporation during development of insects

Abstract

A comparative study on the in vitro and in vivo incorporation of [ 14C]acetate into different classes of lipids by the insect Ceratitis capitata has been carried out. The pattern of labelled lipids obtained in the in vitro experiments depends on both the time of incubation and the stage of development of the insect. Larval homogenates and pharate adult homogenates incorporate rapidly [1- 14C]acetate during the first 60 minutes, mainly into phospholipids. In the in vivo experiments triglycerides account for the highest percentages of incorporation in both stages of development, whereas free fatty acids and phospholipids exhibit lower levels of incorporation. Radioactivity of individual fatty acids present in the lipid classes was determined by gas-liquid radio-chromatography. The specific activity of fatty acids present as free fatty acids in triglycerides increased during the larval-pharate adult transition, whereas that of those present in phospholipids decreased. Relative abundance of monoenoic fatty acids synthesized de novo generally decreased from larvae to pharate adults. Triglycerides from both larvae and pharate adults showed the highest levels of unsaturation.