Oxidative Assimilation of Acetate by Euglena. Carbon Balance and Effects of Ethanol*

Oxidative assimilation of acetate by Euglena gracilis was studied using methyl‐ and carboxyl‐labeled radioactive acetate. Of the total carbon utilized, 40% was oxidized to CO2 and 60% was assimilated; 20% of the CO2 produced was derived from the methyl carbon, and 80% from the car‐boxyl carbon of acetate. Seventy % of the carbon assimilated was derived from the methyl carbon and 30% from the carboxyl. The results suggest that assimilation involves decarboxylation of Krebs‐cycle oxalacetate and assimilation of the resulting pyruvate. In the presence of ethanol a greater proportion of the acetate carbon is assimilated, though the total acetate consumption is almost unchanged.