The Metabolic Activity of Various Colon-group Organisms at Different Phases of the Culture Cycle

Abstract

Comparative studies on Escherichia coli, Salmonella pullorum and S. gallinarum, when cultivated under continuous aeration, indicate that the production of CO2 per cell per hr. is essentially independent of the species of organism studied and of the medium used. At various stages of the culture cycle, however, the rate of metabolic activity varies very widely; at the beginning of the phase of logarithmic increase, it is 50 times as high as in the stable phase on the 2d day. A part, but only a part, of this increase is due to variation in cell size. In comparison with other organisms the bacteria, even in the stable 2d-day phase, produce more than 40 gms. of CO2 per hr. per kgm. of body weight. This indicates an activity 40 times as great as that shown by a protozoan, 100 times as great as that shown by man, and 4 times as great as that shown by the sparrow.