Oxidative damage and induced mutations in m13mp2 phage DNA exposed to N-nitrosopyrrolidine with UVA radiation.

N:-Nitrosopyrrolidine (NPYR) is carcinogenic in rodents and undergoes alpha-hydroxylation upon microsomal CYP450 metabolism, giving rise to mutations. Previously, we reported the direct mutagenicity of NPYR, under ultraviolet A (UVA) irradiation, towards Salmonella typhimurium and phage M13mp2. In the present study, we measured the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) in a replicative form of M13mp2 DNA exposed to NPYR plus UVA.

Induced mutations in M13mp2 phage DNA exposed to N-nitrosopyrrolidine with UVA irradiation.

It is known that N-nitrosopyrrolidine (NPYR), a carcinogen in rodents, is metabolically activated by microsomal cytochrome P450 to form an alpha-hydroxylated derivative, which induces mutations. The mutations have been demonstrated by use of Salmonella typhimurium and Escherichia coli. We discovered directly acting mutagenicity of NPYR plus ultraviolet light-A (UVA) in bacteria and phage.