We used alkA′-lacZ′ and umuC′-lacZ′ fused genes and determined the ability of various alkylating agents to induce adaptive and SOS responses. The degree of induction of expression of these genes was quantitatively measured by a simple colorimetric assay of ß-galactosidase activity. SN1 type methylating agents, such as N-methyl-N′-nitro-N-nitrosoguanidine and B-methyl-N-nitrosourea, were more effective inducers for the alkA than for the umuC system, while SN1 type ethylating agents, such as N-ethyl-N′-nitro-N-nitrosoguanidine and N-ethyl-N-nitrosourea, were more potent inducers for the umuC than for the alkA system. Similar but less striking effects on the two systems were obtained with SN2 type alkylating agents.
All Science Journal Classification (ASJC) codes