Influence of starvation for methionine and other amino acids on subsequent bacterial deoxyribonucleic acid replication.

Abstract

Billen, Daniel (University of Texas M. D. Anderson Hospital and Tumor Institute, Houston, Tex.), and Roger Hewitt. Influence of starvation for methionine and other amino acids on subsequent bacterial deoxyribonucleic acid replication. J. Bacteriol. 92:609-617. 1966.-A study has been made of the subsequent replicative fate of deoxyribonucleic acid (DNA) synthesized during amino acid starvation by several multiauxotrophic strains of Escherichia coli. Using radioisotopic and density labels and a procedure whereby total cellular DNA is analyzed, we have confirmed and extended a recent report that the DNA made during amino acid starvation behaves anomalously during subsequent DNA replication. When 5-bromouracil (BU) serves as the density lable, 40% or more of the DNA synthesized during starvation will subsequently fail to replicate during three cell generations. Selective amino acid effects were noted. In two methionine-requiring bacteria, methionine deprivation appeared to be of singular importance in influencing the subsequent replicative fate of the DNA made in its absence. When a non-BU density label (N(15), C(13)) was utilized, the effects of amino acid starvation were less obvious. Although the DNA synthesized during complete amino acid starvation in a methionine-requiring E. coli was subsequently more slowly replicated, most of the DNA was finally duplicated during three generations of growth. If methionine was present during starvation for other required amino acids, the subsequent replication rate of the DNA synthesized during this time was more nearly normal, and complete replication was observed. The results have been interpreted as indicating that DNA synthesized during amino acid starvation, and especially during methionine starvation, is somehow altered, and that BU substitution for thymine may interfere with the restoration of such DNA to its replicative state.