The Synthesis of Nucleic Acids in Cultures of Escherichia Coli, Strains B and B/r.

Although many investigations concerning the content of nucleic acids in bacterial cells have been reported (Stacey, 1948; Belozersky, 1947; Boivin, 1948), no systematic study of nucleic acid synthesis during growth was undertaken until the studies of Malmgren and his co-workers (1945, 1947a,b,c,d,e) and of Cohen (1948). The results of the study of Malmgren and co-workers showed that the total nucleotide content of the individual cells of a culture changed during the growth of the culture, being at a maximum in cells near the end of the lag phase of the culture cycle. Cohen observed the rapid synthesis of ribose nucleic acid in his cultures following inoculation. These observations are in agreement with those of Belozersky and Boivin, who observed that cells from young cultures contained more nucleic acid than those from old cultures. Preliminary to a study of the effects of ultraviolet and X radiation on the metabolism of nucleic acids in Escherichia coli, strains B and B/r, the present study was undertaken to establish, by means of microchemical procedures and with the use of radiophosphorus, the normal patterns of synthesis of ribonucleic and desoxyribonucleic acids in cultures of these microorganisms.