THE EFFECT OF CYANIDE ON RESPIRATION IN PARAMECIUM CAUDATUM AND PARAMECIUM AURELIA

Abstract

Using proper absorption mixtures in Barcroft-Warburg manometers, it was found that O2 consumption in P. caudatum and P. aurelia is partially inhibited by KCN and that the extent of inhibition is dependent upon the food content of the organisms as well as upon the conc. of cyanide in soln. Starved specimens proved to be non-sensitive to cyanide while old specimens (with low food content) were not as sensitive as young specimens (with high food content). The effect of cyanide on respiration in Paramecium evidently depends upon the degree of saturation of the respiratory mechanism with carbohydrates for, in a 0.1 M dextrose soln., inhibition by cyanide was much greater than in the same soln. minus dextrose.