THE EFFECT OF GLUCOSE ON THE DEVELOPMENT OF RESPIRATION BY ANAEROBICALLY GROWN YEAST

Abstract

Yeast cells grown anaerobically on glucose supplemented with yeast extract, hydrolyzed casein, and oleic acid developed a respiratory capacity on exposure to air. The time course of development of respiration was characteristic with an abrupt onset of oxygen consumption. The magnitude of the uptake of oxygen and the kinetics of its onset were determined by the concentration of glucose to which the yeast was exposed during growth and by the relative amounts of glucose and yeast present during the time of adaptation. A source of amino acids was necessary during the time of adaptation for the consistent development of respiration. Under the growth conditions used, adaptive development of respiration occurred most efficiently when the cells were harvested immediately prior to the onset of the stationary phase. Cytochrome oxidase was virtually absent from the anaerobically grown cells. The kinetics of its adaptive formation were not the same as those for the development of respiration. Cytochrome oxidase appeared before respiration became appreciable. When these anaerobically grown yeast cells were added to the adaptation medium there was a burst of gas output. The identity of the gas is unknown but it is likely to be CO2, H2S, or H2. The role of glucose and other factors in the adaptive development of respiration in yeast is discussed.