Variation in the Phosphorus Content of Escherichiu coli during Cultivation

SUMMARY: Wide fluctuations of phosphorus concentration in the cells occur during the cultivation of Escherichia coli (Bacterium coli) on aerated media. The concentra-tion of cell phosphorus increases rapidly during the stationary phase and early lag phase to a peak which coincides with the formation of half the first generation; it declines until the end of this generation and increases once again to a second peak, declining subsequently when growth and division rates fall off. Analyses of the cells during cultivation show that the different concentrations of ribonucleic acid largely account for these variations. The association of the initial phosphorus peak with the first generation has been observed during the cultivation of Esch. coli on several liquid media and on CCY medium a t different temperatures. The increase in phosphorus concentration during the first generation can be associated quantitatively with the increase in average cell weight. Variations in the phosphorus concentration of bacteria at different periods of growth were recorded by Leach (1906) and by Dawson (1919), but the bacteria used were for the most part derived from agar surfaces and were in consequenc