Glycerolipid metabolism in Ascaris lumbricoides

Abstract

Homogenates of ovarian tissue from the pig roundworm Ascaris lumbricoides rapidly incorporate fatty 14C-acids, fatty 14C-acyl-CoA derivatives, glucose, and glycerol into lipid, the most highly labeled fraction after prolonged incubation periods being the triglycerides (except with glucose). Data from studies on the time course of incorporation of these precursors is consistent with the operation of the phosphatidic acid – diglyceride pathway for biosynthesis of these lipids. However, formation and acylation of monoglyceride may also contribute to their synthesis. Determination of the composition and labeling pattern of the triglyceride species indicated that some species turn over more rapidly than others, perhaps reflecting different metabolic roles. In these experiments, only small amounts of the precursors were incorporated into phospholipids other than phosphatidic acid.

Biosynthesis of lipids during embryogenesis of Ascaris lumbricoides eggs.

“…The concentrations of the branched C15 fatty acid, are 1.6 to 2.0% of the total fatty acid in eggs at all stages of embryonation. This observation is consistent with the results previously mentioned by Jezyk (1968) and Tarr and Fairbairn (1973), who reported 1.9% and 1.24% of the fatty acid in ovarian triglyceride of Ascaris him bricoides, respectively. In aerobic conditions, it was observed that the incorporation of radioactivity in C18,1 acid was decreased and that in branched C15 fatty acid was greatly increased in the second stage larvae compared with the first stage larvae.…”

“…The increase of acetate-1-14C incorporation into isopentadecanoic acid in second stage larvae observed in this investigation suggests that there may be a developmental change in fatty acid synthesis in the larvae during embryonation of Ascaris eggs. The fatty acid, isopentadecanoic acid, has been found in only a small percentage (1.9 %) in ovarian triglyceride of Ascaris lumbricoides (Jezyk 1968). In contrast, the free living spirochete Treponema zuelzerae contains a large amount of the iso-15 : 0 fatty acid (16.4%) (Meyer and Meyer 1971).…”

“…The synthesized fats of the adult are stored in the eggs and larvae where they may be utilized as an energy source in development (Fairbairn 1960). The general characteristics and metabolism of the lipids of Ascaris (Beanies et al 1967) and triglyceride utilization or the conversion of triglycerides to carbohydrates in devoloping eggs of Ascaris lumbricoides are known in some detail (Jezyk andFairbairn 1969: Barrett et al 1970), but information on the fatty acid biosynthesis of the larvae is quite limited. The present report deals with changes in the ability to synthesize lipids and fatty acid biosynthesis during the embryonation in Ascaris lumbricoides eggs.…”

Studies on the hydrolysis and utilization of long chain acyl CoA thioesters by liver microsomes

“…Alternatively, 3H-palmitoyl CoA was used as the substrate, and the reaction stopped at the appropriate time by addition of 5 volumes of chloroformmethanol, 2:1 (5). The extracted lipids were separated by thin layer chromatography (TLC), each fraction scraped from the plates and the radioactivity determined in a Nuclear-Chicago liquid scintillation spectrometer (6).…”

Hepatic Lipid Metabolism in Hypophysectomized and Growth Hormone-Treated Hypophysectomized Rats

“…This separation scheme yielded four discrete fractions of the following composition: neutral lipids (vials 1-3) ; acidic lipids (vials 4-6), consisting of phosphatidic acid, cardiolipin, swine phosphoglycerides, and some inositol phosphoglycerides; cephalin (vials 7-10), consisting of ethanolamine and inosi to1 phosphoglycerides ; and lecithin (vials [11][12][13][14], consisting of choline phosphoglycerides and sphingomyelin. The lipid content of each of these fractions was determined by thin-layer chromatography as previously described (9).…”