title: Plasmid R46 fails to protect Escherichia coli against double-strand DNA-binding agents but increases their mutagenic activities.
abstract: Plasmid R46 was tested for its ability to increase survival and mutagenesis of Escherichia coli strain AB1157 following exposure to agents that produce a variety of structural defects in DNA. The plasmid enhanced the mutagenic activities of adriamycin (ADM), N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU), bleomycin (BLM), methyl methanesulphonate (MMS), mitomycin C (MTC), nitrofurazone (NFZ), 4-nitroquinoline-N-oxide (NQO), cis-platinum (II) diaminodichloride (PDD) and proflavine (PF). Furthermore, R46, which is known to protect against BLM and MMS, increased the survival of strain AB1157 following exposure to NFZ, NQO or PDD but not ADM, BCNU, MTC or PF. In fact the plasmid appeared to slightly sensitise its host to the latter drugs. The results are discussed in terms of the nature of the DNA damage produced by these inhibitors and the possible role of plasmid-encoded products in the repair of DNA.
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002273:Carcinogens / Q000494:pharmacology*; D004260:DNA Repair; D004269:DNA, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D009152:Mutagenicity Tests; D009153:Mutagens; D009154:Mutation; D010957:Plasmids
chemical_list: D000970:Antineoplastic Agents; D002273:Carcinogens; D004269:DNA, Bacterial; D009153:Mutagens