THE SYNTHESIS OF NUCLEIC ACIDS IN CULTURES OF ESCHERICHIA COLI, STRAINS B AND B/R

Abstract

A study of the synthesis of ribose nucleic acid (RNA) and desoxyribose nucleic acid (DNA) in cultures of E. coli B and E. coli B/r, made by means of the orcinol and diphenylamine tests, respectively, revealed that large amts. of the nucleic acids were synthesized during the lag phase. This was confirmed by the use of radiophosphorus as an indicator of nucleic acid synthesis. In cultures of both strains, the avg. increase per cell during the lag phase was, for RNA, 5- to 10-fold, and for DNA, 2-fold. Cells of the B/r strain, when taken from a 24-hr. broth culture, however, contain 3-4 times more DNA than cells of the B strain when taken from a culture of similar age. After division commenced, the avg. DNA content of the B/r cells fell to approx. 1/4 the initial content. In the B cells the avg. DNA content fell to its initial figure.