Bacteriophage development in lysogenic Escherichia coli and mutations in fungi induced with analogs of tris(1‐aziridinyl) phosphine oxide, TEPA

Tris(1‐aziridinyl)phosphine oxide, TEPA, an alkylating agent used to sterilize insect males, five diaziridinyl analogs, one monoaziridinyl analog, and HEMPA, a nonalkylating analog, have been tested for induction of bacteriophage development in two lysogenic strains of Escherichia coli , K12(Λ) and K39(Δ). The inductive capacity depends on the number of aziridinyl rings. TEPA was the most effective, and HEMPA was without effect. The varying length of the carbon chain in the alkyl groups of the diaziridinyl compounds did not significantly influence induction capacity. E. coli K12(Λ) was much more sensitive to the killing effect of the alkylating compounds than strain K39(Λ). The bifunctional compounds were as toxic as the trifunctional TEPA, while the monofunctional compound tested was much less toxic. The results indicate that alkylation per se is more important than cross‐linking of the DNA twin‐strands for induction of phage development. TEPA and four diaziridinyl analogs induced back‐mutations to prototrophy in a methionine‐requiring strain of Schizosaccharomyces pombe. TEPA was not mutagenic in Ophiostoma multiannulatum or Saccharomyces cerevisiae but induced respiration deficiency in Saccharomyces. The results are discussed and compared with the biological effects obtained in other organisms with TEPA and analogs.