THE ENDOGENOUS RESPIRATION OF MICROORGANISMS

Abstract

Cells of the alga Chlorella vulgaris. the fungus Zygorhyncus moelleri, and baker s yeast were made radioactive with C14.The effect of the presence of various substrates and inhibitors on the rate of evolution of Cl4O2 was investigated. Generally, the C14O2 production in the presence of an external oxidizable substrate was either unaffected or was somewhat stimulated. Sodium azide and 2;4-dinitrophenol stimulated both the endogenous respiration and the C14O2 evolution; the presence of glucose together with inhibitor suppressed the increased rate of C14O2 evolution. ALthough these results appear to indicate that the endogenous respiration is not suppressed by the presence of an external substrate, it is pointed out that other interpretations are possible.