ENDOGENOUS RESPIRATION AND OXIDATIVE ASSIMILATION IN NOCARDIA CORALLINA

Abstract

The respiratory quotients for the endogenous respiration of N. corallina Strain S, grown for different times on various C substrates were all in the range 0.89 to 1.00. The rates of endogenous respiration were increased with certain concentrations of Na azide and 2,4-dinitrophenol. A relationship was demonstrated between the rate of substrate oxidation (with acetate, propionate and glucose) and the rate of endogenous respiration of the cells used. Cells showing no endogenous respiration oxidized acetate, and the mechanism presumably involved the glyoxylate by-pass system. Oxidative assimilation was shown to occur during the oxidation of l-Cl4-acetate, 3-Cl4-propionate, and U-C14-glucose by cell suspensions. The release of C14 from the labelled cells was faster for cells oxidizing unlabelled propionate and acetate than for cells respiring endogenously. Glucose had little effect on the release of Cl4O2 from the cells. The distribution of C14 in the constituents of cells which had oxidized C14-labelled substrates was studied.