title: Role of the uvr gene in the SOS function inducing activity of two tryptophan pyrolysis products, Trp-P-1 and Trp-P-2, in Escherichia coli K12.
abstract: Two tryptophan pyrolysis products, Trp-P-1 and Trp-P-2 were assayed in the SOS-chromotest using PQ 37 (uvr A) and PQ 35 (uvr+) E. coli K12 strains, in the presence of S9 fraction from Aroclor-induced rats. Both compounds were able to induce the expression of SOS functions in uvr A bacteria, in the following order: Trp-P-1 less than Trp-P-2 less than aflatoxin B1, at low concentrations (less than 125 ng/assay). In this range, the induction of SOS functions was significantly decreased in the uvr+ strain. This implies that the uvr gene product plays an important role in the repair of genotoxic damage induced by Trp-P-1 and Trp-P-2. At higher concentrations (125-500 ng/assay), Trp-P-1 became more efficient in inducing SOS functions than Trp-P-2 and excision repair was less efficient than at low concentration.
mesh_terms: D016604:Aflatoxin B1; D000348:Aflatoxins / Q000494:pharmacology; D001426:Bacterial Proteins / Q000502:physiology*; D002243:Carbolines / Q000494:pharmacology*; D004260:DNA Repair / Q000187:drug effects*; D004790:Enzyme Induction / Q000187:drug effects; D005798:Genes, Bacterial; D009152:Mutagenicity Tests
chemical_list: D000348:Aflatoxins; D001426:Bacterial Proteins; D002243:Carbolines; C019133:3-amino-1-methyl-5H-pyrido(4,3-b)indole; D016604:Aflatoxin B1; C019132:3-amino-1,4-dimethyl-5H-pyrido(4,3-b)indole