Construction and characterization of Pseudomonas aeruginosa protein F-deficient mutants after in vitro and in vivo insertion mutagenesis of the cloned gene

W. A. Woodruff, Robert Hancock

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Abstract

Mutants with insertion mutations in the Pseudomonas aeruginosa protein F (oprF) gene were created in vivo by Tn1 mutagenesis of the cloned gene in Escherichia coli and in vitro by insertion of the streptomycin resistance-encoding Ω fragment into the cloned gene, followed by transfer of the mutated protein F gene back to P. aeruginosa. Homologous recombination into the P. aeruginosa chromosome was driven by a bacteriophage F116L transduction method in the oprF::Tn1 mutants or Tn5-instability in the oprF::Ω mutants. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblotting demonstrated that the resultant oprF insertion mutants had lost protein F, whereas restriction digestion and Southern blotting experiments proved that the mutants contained a single chromosomal oprF gene with either Tn1 or Ω inserted into it. It has been proposed that protein F has a role in antibiotic uptake in P. aeruginosa. Measurement of antibiotic resistance levels showed small to marginal increases in resistance, compared with that of the parent P. aeruginosa strain, to a variety of β-lactam antibiotics. Protein F-deficient mutant had altered barrier properties as revealed by a three- to fivefold increase in the uptake of the hydrophobic fluorescent probe 1-N-phenylnaphthylamine.

Original languageEnglish
Pages (from-to)2592-2598
Number of pages7
JournalJournal of bacteriology
Volume170
Issue number6
DOIs
Publication statusPublished - 1 Jan 1988
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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