Increased amplification of pBR322 plasmid deoxyribonucleic acid in Escherichia coli K-12 strains RR1 and chi1776 grown in the presence of high concentrations of nucleoside

Abstract

When pBR22 plasmid-harboring E. coli strains RR1 or .chi.1776 were grown in the presence of 1 mg of uridine or cytidine/ml and later treated with chloramphenicol, as much as 3 times more plasmid DNA was recovered than would normally be obtained by routine plasmid amplification procedures.