STUDIES ON THE ENDOGENOUS METABOLISM OF ESCHERICHIA COLI.

1. The endogenous metabolism of Escherichia coli has been studied by examining changes in cellular composition and of the suspending fluid during starvation of washed suspensions of the organism, in water or in phosphate buffer, at 37 degrees under aerobic and anaerobic conditions. 2. When E. coli is grown in glucose-ammonium salts media the cells contain glycogen, which is utilized rapidly during subsequent starvation of the cells. 3. Ammonia is released by starved cells only after a lag period, which corresponds to the time taken for the cellular glycogen to be almost completely utilized. 4. If cells are grown under conditions that permit incorporation of (14)C into protein but not into glycogen and are then starved, release of (14)CO(2) commences immediately and continues at a linear rate throughout the period of glycogen utilization; it is concluded that the presence of glycogen in the cell prevents the net degradation of nitrogenous materials but does not suppress protein turnover. 5. RNA is degraded by the cells immediately they are starved, ribose is oxidized and ultraviolet-absorbing materials are released to the suspending medium. 6. There is no significant utilization of lipid during the starvation of glucose-grown E. coli. 7. There is no loss of viability during the initial 12hr. period of starvation under either aerobic or anaerobic conditions, but thereafter the cells die more rapidly under conditions of anaerobiosis. 8. These results are discussed in relation to the known patterns of endogenous metabolism and survival of other bacteria.