The U.V. sensitivity of bacteria: its relation to the DNA replication cycle

Author: Hanawalt, P.C.

Description: A striking increase in the shoulder of the UV survival curve but no change in the limiting slope is obtained when cultures of Escherichia coli strain TAU complete the DNA replication cycle in the absence of concommitant protein synthesis prior to irradiation. The UV sensitivity of protein synthesis or RNA synthesis is not altered significantly by this treatment.

In contrast to the result for strain TAU, there is no significant change in the UV survival curve for the UV sensitive E. coli Bs-1 when its DNA replication cycle is completed under similar conditions.

Following a period of inhibited protein synthesis, there is a delay in the reinitiation of the normal DNA replication cycle when protein synthesis resumes. This delay would allow time for an intracellular repair system to operate before the attempted resumption of normal replication. Strain Bs-1, which is deficient in this repair system, would not be expected to benefit from such a delay, as consistent with the observed results. A model is presented to account for lethality due to attempted DNA replication during a period of repair synthesis. The maximum survival for a given UV dose would be predicted for a culture which has completed the normal DNA replication cycle prior to irradiation and which is not permitted to reinitiate the cycle until all possible repair synthesis is completed.

Subject headings: DNA, Bacterial; Escherichia coli/radiation effects; Ultraviolet Rays; Nuclease

Publication year: 1966

Journal or book title: Photochemistry and Photobiology

Volume: 5

Issue: 1

Pages: 1-12

Find the full text :

Find more like this one (cited by):,16&hl=en

Type: Journal Article

Serial number: 530