FIG. 2.

Kinetics of spontaneous DNA degradation in various E. coli strains. A full description of the strains is given in Table 1. Cells were pretreated with [³H]thymidine and then grown in nonradioactive medium. Samples were withdrawn at the indicated times, and the amounts of acid-precipitable ³H were determined. The values are averages of two to four independent measurements, with error bars representing standard deviations.