title: New translocation sequence mediating tetracycline resistance found in Escherichia coli pathogenic for piglets.
abstract: A discrete piece of deoxyribonucleic acid coding for tetracycline (Tc) resistance was found to move from one R plasmid to another in an Escherichia coli strain which is pathogenic for piglets. Since this phenomenon took place also in rec strains, the Tc segment was classified as a transposon and called Tn804. Restriction enzyme analysis with EcoRI, BglII, and HindIII indicated that Tn804 is related to Tn10, a well-known transposon that codes for resistance to tetracycline. Hybridization between plasmids carrying the two transposons provided proof of homology between Tn10 and prt of Tn804. Electron microscopic studies showed a transposon-like structure composed of one loop-stem structure with inverted repetitions of approximately 0.9 megadaltons inserted into the loop of a second loop-stem structure. It is suggested that Tn804 is composed of Tn10 plus another transposable sequence.
mesh_terms: D000818:Animals; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity; D011815:R Factors; D013552:Swine; D013553:Swine Diseases / Q000209:etiology*; D013754:Tetracyclines / Q000494:pharmacology*; D014178:Translocation, Genetic
chemical_list: D013754:Tetracyclines