Biosynthesis and Composition of Sterols in Annelida. Ii. Investigations On Some Oligochaetes

The oligochaetes Lumbricus terrestris, Tubifex tubifex and Enchytraeus buchholtzi are able to synthesize saponifiable and non-saponifiable lipids from sodium acetate or DLmevalonate. The aquatic Tubifex and the terrestrial Enchytraeus were also capable of synthesizing sterols from sodium acetate-1-¹⁴C. On the contrary the terrestrial Lumbricus terrestris did not show any biosynthesis of sterols either from sodium acetate-1-or 2-¹⁴C, or from DL-mevalonate-2-¹⁴C. It seems unlikely that this phenomenon in Lumbricus is correlated to its terrestrial way of living. Sterol composition of the species investigated show strong resemblance; cholesterol in all cases being the main sterol. 22-Dehydrocholesterol was only present in the aquatic species, desmosterol only in the terrestrial ones. In Lumbricus trace amounts of ergosterol were present, suggesting that part of the diet consists of fungi.