title: Isolation and prevalidation of an Escherichia coli tester strain for the use in mechanistic and metabolic studies of genotoxins.
abstract: We have isolated an Escherichia coli tester strain for the use in mechanistic and metabolic studies of genotoxins. We started with one of the more used and better characterized E. coli K-12 laboratory strains, AB1157. We isolated a lipopolysaccharide defective mutant of strain AB1886 which is an excision repair deficient derivative of AB1157 and introduced a newly constructed plasmid pKR11, encoding mucAB, resulting in strain MR2101/pKR11. A genotoxicity assay was designed, monitoring the reversion to arginine prototrophy and a preliminary validation was carried out against Ames tester strain TA100 with a set of diagnostic compounds. The results seem to indicate that strain MR2101/pKR11 is an adequate tester strain which can be a useful tool in mechanistic studies. Moreover, this strain can serve as mother strain to isolate improved and more specialized tester strains.
authors.affiliation: Department of Genetics, Faculty of Medical Sciences, UNL, Lisbon, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Kranendonk
authors.forename: M
authors.initials: M
authors.lastname: Ruas
authors.forename: A
authors.initials: A
authors.lastname: Laires
authors.forename: J
authors.initials: J
authors.lastname: Rueff
mesh_terms: D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008070:Lipopolysaccharides; D009152:Mutagenicity Tests / Q000379:methods*; D009153:Mutagens / Q000633:toxicity*; D009876:Operon; D011135:Polysaccharides, Bacterial / Q000235:genetics*; D015203:Reproducibility of Results; D013014:SOS Response, Genetics / Q000235:genetics*; D012486:Salmonella typhimurium / Q000187:drug effects; D014161:Transduction, Genetic
chemical_list: D008070:Lipopolysaccharides; D009153:Mutagens; D011135:Polysaccharides, Bacterial