Mutants ofEscherichia colisensitive to methylene blue and acridines

Abstract

A mutant (Mb-s) ofEscherichia coliK12 which is more sensitive than wild-type (Mb-r) to such dyes as methylene blue or acridines was studied. TheMb-smutant can also be disinfected of F factor with lower concentrations of acridine orange thanMb-rbacteria. TheMblocus was mapped by crosses between Hfr and F−, F-duction with F13, and transduction with phage P1. It was found to be situated between thepurandT₆loci on the chromosome. Moreover, it was found to be contained in the chromosomal fragment carried by the F-prime, F13. In a heterogenote obtained by F-duction, theMb-rgene is dominant over theMb-sgene. TheMbgene was transduced jointly with thepurgene by phage P1.