DNA Segregation in Escherichia coli: Observations by Means of Tritiated Thymidine Decay

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Science  03 Jan 1964:
Vol. 143, Issue 3601, pp. 44-46
DOI: 10.1126/science.143.3601.44


Escherichia coli, strain 15T-L-, inactivation by H3-thymidine decay was used in a study of DNA segregation. Two characteristics of the inactivation curves due to H3-thymidine decay, the initial slope and stable fraction, enable the mode of segregation to be defined. The results suggest that the segregation pattern is consistent with a semiconservative model of DNA replication. The data on the stable fraction indicate that the DNA of strain 15T-L-, under our experimental conditions, may be organized into one duplex structure. Since colony-forming ability was used as the means of assay, it is possible to compare these experiments with those in which DNA segregation is examined on a structural basis.