Effect of Some Inhibitors Derived from Nitrite on Macromolecular Synthesis in Bacillus cereus

The effect of several inhibitors derived from nitrite on incorporation of [14C]uracil into ribonucleic acid of Bacillus cereus during outgrowth and vegetative growth has been determined. A heat-induced inhibitor presumably of the Perigo type was compared with the nitrosothiols of thioglycolate and beta-mercaptoethanol. All were found to effectively inhibit uracil incorporation at all stages tested. Phase-contrast microscopy revealed that inhibition of morphological events occurred either before germination or during early outgrowth, depending on inhibitor concentration. It was also found that a precursor to the heat-induced inhibitor could be isolated from dialyzable tryptone (a pancreatic digest of casein), which chromatographed as a single species on diethylaminoethyl-cellulose and Sephadex G-25, with an apparent molecular weight of about 2,000.