Quantitative radioautographic studies on exponentially growing cultures of Escherichia coli. The distribution of parental DNA, RNA, protein, and cell wall among progeny cells.

Exponentially growing cultures of E. coli were examined by quantitative radioautographic techniques to determine the distribution of labeled DNA, RNA, protein, and cell wall among the progeny cells of successive generations. It was found that DNA is in large structures, non-randomly distributed in the progeny. About one-half of the cells have four such structures and approximately one-half contain these four structures plus four smaller ones. These structures show remarkable stability. Fewer than 3.5 per cent of the large structures break in one division time. Protein, RNA, and cell wall are all distributed randomly among progeny cells. The number of units of each component that show random segregation must be 200 or more.