FILAMENT FORMATION AND RESISTANCE TO 1-METHYL-3-NITRO-1-NITROSOGUANIDINE AND OTHER RADIOMIMETIC COMPOUNDS IN ESCHERICHIA COLI

Abstract

A group of compounds, most of which have antitumor activity and are considered radiomimetic, were tested against Escherichia coli strain S and first and second step mutants resistant to 1-methyl-3-nitro-1-nitrosoguanidine (S/Ng 1 and S/Ng 2). The effects on growth as measured by diameter of zone of inhibition, turbidity, and cell division (measured by the presence or absence of filaments) were observed. All the compounds tested, except 6-diazo-5-oxo-L-norleucine and alkylating agents with benzimidazole as a carrier, produce filaments in E. coli. The methyl-nitrosoguanidine-resistant strains were resistant to all the nitrosoguanidines tested, including 1 condensed, imidazolfne compound. These strains were not resistant to any of the other agents tested, but were hypersensitive to Mitomycin C and to nitrogen mustard. Neither first nor second step mutants responded to the compounds by filament formation. The tendency toward filament formation in the presence of radiomimetic compounds was lost with the first step toward nitro-soguanidine resistance.