Metabolic Activity of the Bacterial Cell at Various Phases of the Population Cycle

Abstract

EARLIER STUDIES OF BACTERIAL METABOLISM Nitrogen metabolism. Studies of bacterial metabolism have, in general, centered about either nitrogen or carbon metabolism or the interrelationship of these two processes. The general principles of nitrogenous metabolism in relation to cell structure, synthesis, katabolism, proteolysis and putrefaction, utilization of atmospheric nitrogen or ammonia and the like have recently been concisely and clearly reviewed by Rettger (1928). Some of the well established points of particular bearing on the present study are that an available source of nitrogen is the sine qua non of bacterial growth; that organic nitrogen compounds may also be utilized as sources of carbon and energy; that this utilization is accompanied by changes in the various non-protein nitrogen substances yielding a balance different from that which occurs when a carbohydrate is present; that sugar inhibits proteolysis by raising the acidity of the medium and in other ways as well; and that both utilization and production of ammonia are common properties of practically all bacteria. The carbohydrate metabolism of bacteria has also been recently reviewed by Kendall (1928) in far more detail than could be here set forth. Historical aspects, structural carbon requirements , energy requirements, available compounds, preferential I