Translocation of a plasmid DNA sequence which mediates ampicillin resistance: molecular nature and specificity of insertion.
AUTOR(ES)
Heffron, F
RESUMO
A series of recombinant plasmids was generated in Escherichia coli in which the TEM beta-lactamase translocon (TnA) was inserted into the small plasmid RSF1010. RSF1010 is a 5.5 X 10(6) dalton nonconjugative plasmid which confers resistance to streptomycin and sulfonamide. The recombinant plasmids can be classified into three clearly defined phenotypic groups. Group I is ampicillin-, streptomycin- and sulfonamide-resistant. Group II is ampicillin- and sulfonamide-resistant but has lost streptomycin resistance. Group III is ampicillin-resistant but is sensitive to sulfonamide and shows a simultaneous 30-fold reduction in the minimal inhibitory concentration of streptomycin. It was possible to map the site of insertion of TnA within RSF1010 by electron microscope studies of DNA heteroduplexes formed between RSF1010 and recombinant plasmids. Insertions of TnA occur at, at least, 12 distinct sites in a region corresponding to one-third of the RSF1010 DNA molecule. Those insertions giving rise to particular phenotypes are clustered. Insertions of TnA-like insertion sequences (IS) appear to give rise to strongly polar mutations.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=433048Documentos Relacionados
- Transposition of a plasmid deoxyribonucleic acid sequence that mediates ampicillin resistance: independence from host rec functions and orientation of insertion.
- Transposition of a plasmid deoxyribonucleic acid sequence that mediates ampicillin resistance: identity of laboratory-constructed plasmids and clinical isolates.
- Molecular nature of a streptomycin and sulfonamide resistance plasmid (pBP1) prevalent in clinical Escherichia coli strains and integration of an ampicillin resistance transposon (TnA).
- Cloned segment of Drosophila melanogaster rDNA containing new types of sequence insertion.
- Transposable plasmid deoxyribonucleic acid sequence in Pseudomonas aeruginosa which mediates resistance to gentamicin and four other antimicrobial agents.
