title: Tn3 as the molecular basis of ampicillin resistance in E. coli--an epidemiological survey.
abstract: Plasmids of 31 E. coli strains coding for the TEM-1 beta-lactamase were analysed for the molecular basis of this enzyme. In transposition experiments we could demonstrate that only 50% of the plasmids were able to transpose their ampicillin-resistance gene. Two of the non-transposing structures were further examined. The 8.1 kb plasmid pBP738 contained Tn3 having suffered a point mutation within the transposase gene that could be complemented by an intact transposase. The 79 kb plasmid pBP749 carried a TEM-1 coding sequence, but the homology with Tn3 was limited to 1.18 kb.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D001435:Bacteriophages; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000648:ultrastructure; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008957:Models, Genetic; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010403:Penicillin Resistance; D011815:R Factors; D014170:Transformation, Genetic; D001618:beta-Lactamases / Q000032:analysis / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D000667:Ampicillin; D001618:beta-Lactamases