R-Factor elimination by thymine starvation

Abstract

SUMMARY R-factor 1818, which is refractory to curing by acridines or ethidium bromide from Escherichia coli K 12 and Klebsiella aerogenes 418 hosts, was eliminated from thymineless mutants of these organisms under conditions of thymine starvation. Neither R-7268 nor R-TEM could be eliminated by this method. The concurrence of R-TEM with R-1818 inhibited the curing of R-1818, whereas R-7268 had no effect on R-1818 elimination