ABSTRACT
The kinetics of degradation of bacterial deoxyribonucleic acid (DNA) after infection of Escherichia coli with T4D, ultraviolet-irradiated T4D, and two amber mutants, N122 and N94, was studied by zone sedimentation through linear glycerol gradients. Within 5 min after infection with any of the bacteriophages, breakdown of host genome was evident. The first product was a high-molecular-weight material (50S to 70S) and further degradation appeared to occur in discrete steps. Rapid and extensive breakdown of bacterial DNA was seen after infection with am N122 and T4D. Infection with ultraviolet-irradiated phage or with am N94 resulted in an accumulation of high-molecular-weight material. These results suggest that the observed degradation of host DNA begins early and requires sequential action of several phage-induced endo- as well as exodeoxyribonucleases.
FOOTNOTES
↵2 Supported by Public Health Service training grant 3T1-GM-151 from the National Institute of General Medical Sciences. Present address: Division of Medical Genetics, Department of Medicine, Washington University School of Medicine, St. Louis, Mo.
↵3 Recipient of National Institutes of Health Research Career Development Award 1-K3-GM-20, 789.
↵1 Presented in part at the 67th Annual Meeting of the American Society for Microbiology, New York, N.Y., 1967.
- Copyright © 1968 American Society for Microbiology
