Utilization of acetate by Tetrahymena geleii (S).

Tetrahymena geleii (S) (Colpidium camp&m) is a ciliated protozoan which has been shown to be capable of synthesizing lipides from protein at an unusually high rate (1, 2). The next obvious step in studies concerned with the metabolism of this organism, therefore, seemed to be a search for the compound, or compounds, serving as precursor of the lipide material. Acetate is known to play a key r&e in the metabolism of lipides, carbohydrates, and proteins (7). Rittenberg and Bloch (8, 9) and Ponticorvo, Rittenberg, and Bloch (10) have shown that acetate may condense to form fatty acids in mammalian tissue. Smedley-MacLean and Hoffert (11) and White and Werkman (12) have demonstrated that in yeast, also, the intact acetate molecule is converted to lipide material. It has also been demonstrated (13-16) that acetate may condense to form higher, non-reducing carbohydrates. The classical work of Schoenheimer and Rittenberg (17) demonstrated that carbohydrate may be transformed into lipides. It therefore seemed of interest to investigate the fate of acetate utilization by T. geleii (S) in an attempt to ascertain whether acetate can serve as a precursor of lipides, and, if so, whether it must first be converted to carbohydrate.