The synthesis of fatty acids from acetate by intact tissue and muscle extract of Ascaris lumbricoides suum

1. 1. Acetate-1- 14C is incorporated into the lipids of Ascaris muscle and reproductive tissue. 2. 2. Determination of the distribution of radioactivity in the various classes of lipids indicates that 70–80 per cent of the acetate is incorporated into ascaroside esters. Six to ten per cent of the radioactivity is incorporated into the glycerides and 1–5 per cent appears in the phospholipids. 3. 3. Acetate- 14C is incorporated into non-volatile fatty acids of both tissues. The saturated 16-carbon acid contains a high percentage of the total radioactivity in both the muscle and ovary-oviduct. Small, but significant radioactivity is present in the unsaturated 18-carbon acids and the acids with 15, 17 and 19 carbons. 4. 4. The supernatant fraction of Ascaris muscle catalyzes the incorporation of acetate into non-volatile acids. Cofactor requirements for the system are similar to those reported for the malonyl-CoA pathway of vertebrates. 5. 5. Adenosine triphosphate activity in Ascaris muscle extract is quite high. The presence of this hydrolytic activity interferes with determinations of fatty acid synthesis in the tissue.