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’.
Goldin, A., Venditti, J. M., and Kline, I., Cancer Res., 19, 429 (1959).
Skinner, W. A., Gram, H. F., Greene, M. O., Greenberg, J., and Baker, B. R., Med. Pharm. Chem. (in the press).
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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Antonie van Leeuwenhoek (1963)