Double-strand scission of DNA involved in thymineless death of Escherichia coli 15 TAU
Review articleOpen access
1973/01/19 Full-length article DOI: 10.1016/0005-2787(73)90293-1
Journal: Biochimica et Biophysica Acta (BBA) - Nucleic Acids and Protein Synthesis
AbstractDouble-strand DNA scissions occurring during thymineless death of Escherichia coli 15 TAU were assayed by neutral sucrose gradient sedimentation of [3H]thymidine-labelled DNA isolated from cells lysed under mild conditions. It was found that, under thymineless conditions, the sedimentation rate of DNA started to decrease only after the cells began to lose their viability. When thymine was added to thymine-starved cultures, the progress of thymineless death was stopped and viable cells began to increase. However, the sedimentation rate of the labelled DNA was not restored to that of the original DNA. These results indicate (1) that thymineless death is accompanied by double-strand scission of DNA, (2) that thymine starvation does not per se cause the DNA scissions but only when cell death ensues, and (3) that the broken DNA cannot be converted back into its original form. It is suggested that double-strand scission of DNA is the principal cause for thymineless death in this case.
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