title: A recombinagenic effect of strychnine in Salmonella typhimurium.
abstract: The aroC321 allele in Salmonella typhimurium permits a positive selection for genetic duplications. Bacteria that contain a large genetic duplication are detected as tryptophan prototrophs in aroC321 strains and occur at a spontaneous frequency greater than 1/10(4) cells plated on the selection medium. Duplications originate by a recombinational mechanism, and the induction of duplications by chemicals or radiation may therefore be considered to be a recombinagenic effect. We have found that strychnine is a potent recombinagen in this system; it causes a dose-dependent increase in the frequency of genetic duplications, and very high frequencies of duplications are recovered at high doses. In contrast, brucine, the 2,3-dimethoxy derivative of strychnine, caused no increase in duplication frequencies under the identical conditions.
mesh_terms: D005810:Multigene Family / Q000187:drug effects*; D011995:Recombination, Genetic / Q000187:drug effects*; D012486:Salmonella typhimurium / Q000187:drug effects*; D013331:Strychnine / Q000494:pharmacology*
chemical_list: D013331:Strychnine