ADAPTIVE CONTROL OF TERMINAL RESPIRATION IN PASTEURELLA PESTIS

Abstract

P. pestis, strain A1122 (avirulent) was grown under aerobic and anaerobic conditions in a casein hydrolysate mineral glucose medium and tested for ability to oxidize glucose, pyruvate, acetate, and tri carboxylic acid cycle compounds. Anaerobically-grown cells oxidize glucose slowly and incompletely, accumulating large amts. of pyruvate and other organic end-products which they are either incapable of oxidizing further or oxidize at a very low rate, while aerobically grown cells carry out an essentially "complete" oxidation of glucose. Other differences in metabolic pattern also exist: anaerobic cells cannot oxidize pyruvate, acetate, or the C4-dicarboxylic acids at appreciable rates, whereas all these compounds are oxidized rapidly by aerobic cells. Anaerobic cells can be converted to the physiological pattern of aerobic cells by aeration for several hrs. in a glucose-casein hydrolysate medium, with negligible increase in the number of cells; this conversion is blocked by u.-v. irradiation. O2 appears to act as an inductor of respiratory enzyme formation, entirely comparable to the results obtained in yeast.