title: Transfer of episome F'lac+ and chromosomal trp+ genes from Erwinia amylovora to Salmonella typhimurium.
abstract: The F'lac+ episome of Escherichia coli origin was transferred by conjugation with frequencies of 10(-7) to 10(-5) from Erwinia amylovora to 14 out of 15 Salmonella typhimurium trp female parents. The chromosomal trp+ genes were transferred with frequencies of 10(-7) to 10(-6) only to one trpB and 2 trpD female parents, which have a point mutation in the 2nd and fourth structural genes, respectively, of the tryptophan operon. The transferred male trp+ genes became integrated at the selected sites of the S. tryphimurium chromosome. The resulting Trp+ hybrids were phenotypically stable, lacked a cryptic trp allele selected against in the female parent, had high genetic homology values in the tryptophan region, and showed biochemical reactions and pathogenicity typical of S. typhimurium.
mesh_terms: D000818:Animals; D002876:Chromosomes, Bacterial; D003227:Conjugation, Genetic; D004885:Erwinia / Q000378:metabolism* / Q000472:pathogenicity; D005111:Extrachromosomal Inheritance; D005144:F Factor; D005796:Genes; D007785:Lactose / Q000378:metabolism; D051379:Mice; D010935:Plant Diseases; D010957:Plasmids; D012486:Salmonella typhimurium / Q000378:metabolism* / Q000472:pathogenicity; D014161:Transduction, Genetic; D014364:Tryptophan / Q000378:metabolism
chemical_list: D014364:Tryptophan; D007785:Lactose