Protein Synthesis and Deoxyribonucleic Acid-Membrane Attachment During Thymineless Death in Escherichia coli

Abstract

The proteins synthesized during thymineless death in Escherichia coli B and B/r were analyzed by polyacrylamide gel elctrophoresis. It was found that the amount of a protein of molecular weight 80,000 to 88,000 is greatly increased during thymineless death compared to the amounts of other cell proteins. A technique for the isolation of cell membrane-deoxyribonucleic acid (DNA)-nascent ribonucleic acid (RNA) complex on detergent crystals was used to determine whether DNA might be detached from the cell membrane as a result of thymineless death. It was found that under no conditions of thymineless death or immunity to thymineless death was there any change in the attachment of DNA or pulse-labeled RNA to cell membrane. When thymine-requiring strains of Escherichia coli are deprived of thymine, there is a permanent loss of colony-forming ability. This phenomenon, termed thymineless death (TLD), was first discovered by Barner and Cohen in 1953 (1). Concomitant with cell death, ribonucleic acid (RNA) and protein synthesis continued, and it was possible to induce the synthesis of some enzymes with or without thymine present (4).

Influence of Thymine Starvation on the Integrity of Episomal and Chromosomal Deoxyribonucleic Acids in Escherichia coli CR34 (λ ind − )

“…On the other hand, sex factor DNA is likely to be associated with the bacterial membrane since it replicates during the growth cycle of the host and segregates at cell division. Thymine starvation apparently does not interfere with the attachment of bacterial DNA to the cellular membrane (2).…”