The Effect of Irradiation on Recombination in Escherichia Coli

Abstract

Several E. coli mutants were tested. Each was unable to synthesize several of the following; biotin, methionine, threonine, leucine and thiamin. When 2 strains with different deficiencies were grown together, organisms (prototrophs of the parent strain) were obtained up to 17 times more frequently after irradiation with u.-v. light. From 2 lactose-negative strains no lactose-positive organisms were found but with one lactose-positive and one lactose-negative strain, 28% of the prototrophs were lactose-positive whether irradiated or not. These data suggest that small amts. of irradiation stimulate a sexual mechanism in bacteria, as measured by the increased rate of recombination.