A Factor in Agar which reverses the Antibacterial Activity of 1-Methyl-3-nitro-1-nitrosoguanidine


WHILE working with 1-methyl-3-nitro-1-nitrosoguanidine, an anticancer agent in mice1,2 and an antibacterial agent in vitro, we observed that Difco agar contained a factor which inhibited the activity of 1-methyl-3-nitro-1-nitrosoguanidine against Escherichia coli strain S. The activity of this compound was tested by the filter paper disk-assay method on minimal3 medium pH 6.8, containing 2 per cent agar. The zones of inhibition were smaller when the medium was sterilized by steaming for 20 min. than when sterilized by autoclaving (15 lb./sq. in.) for the same length of time (Table 1). Several lots of Difco agar had the same property, but other commercially available agars did not. These latters agars are : BBL (Baltimore Biological Laboratory), NBC (Nutritional Biochemical Co.), ‘Ion Agar No. 2’ (Oxo, Ltd., London), and Difco ‘Noble Agar’.


  1. 1

    Goldin, A., Venditti, J. M., and Kline, I., Cancer Res., 19, 429 (1959).

  2. 2

    Skinner, W. A., Gram, H. F., Greene, M. O., Greenberg, J., and Baker, B. R., Med. Pharm. Chem. (in the press).

  3. 3

    Davis, B. D., and Mingioli, E. S., J. Bact., 60, 17 (1950).

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GREENBERG, J. A Factor in Agar which reverses the Antibacterial Activity of 1-Methyl-3-nitro-1-nitrosoguanidine. Nature 188, 660 (1960). https://doi.org/10.1038/188660a0

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