title: Breaking the Permeability Barrier of Escherichia coli by Controlled Hyperporination of the Outer Membrane.
abstract: In Gram-negative bacteria, a synergistic relationship between slow passive uptake of antibiotics across the outer membrane and active efflux transporters creates a permeability barrier, which efficiently reduces the effective concentrations of antibiotics in cells and, hence, their activities. To analyze the relative contributions of active efflux and the passive barrier to the activities of antibiotics, we constructed Escherichia coli strains with controllable permeability of the outer membrane. The strains expressed a large pore that does not discriminate between compounds on the basis of their hydrophilicity and sensitizes cells to a variety of antibacterial agents. We found that the efficacies of antibiotics in these strains were specifically affected by either active efflux or slow uptake, or both, and reflect differences in the properties of the outer membrane barrier, the repertoire of efflux pumps, and the inhibitory activities of antibiotics. Our results identify antibiotics which are the best candidates for the potentiation of activities through efflux inhibition and permeabilization of the outer membrane.
authors.affiliation: University of Oklahoma, Department of Chemistry and Biochemistry, Norman, Oklahoma, USA.
authors.forename: Ganesh
authors.initials: G
authors.lastname: Krishnamoorthy
authors.affiliation: University of Oklahoma, Department of Chemistry and Biochemistry, Norman, Oklahoma, USA.
authors.forename: David
authors.initials: D
authors.lastname: Wolloscheck
authors.affiliation: University of Oklahoma, Department of Chemistry and Biochemistry, Norman, Oklahoma, USA.
authors.forename: Jon W
authors.initials: JW
authors.lastname: Weeks
authors.affiliation: University of Oklahoma, Department of Chemistry and Biochemistry, Norman, Oklahoma, USA.
authors.forename: Cameron
authors.initials: C
authors.lastname: Croft
authors.affiliation: University of Oklahoma, Department of Chemistry and Biochemistry, Norman, Oklahoma, USA.
authors.forename: Valentin V
authors.initials: VV
authors.lastname: Rybenkov
authors.affiliation: University of Oklahoma, Department of Chemistry and Biochemistry, Norman, Oklahoma, USA elenaz@ou.edu.
authors.forename: Helen I
authors.initials: HI
authors.lastname: Zgurskaya
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001089:Arabinose / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002462:Cell Membrane / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002463:Cell Membrane Permeability / Q000187:drug effects; D004917:Erythromycin / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D015870:Gene Expression; D019450:Genes, MDR; D005818:Genetic Engineering; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D018272:Porins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014169:Transformation, Bacterial; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D018272:Porins; D011994:Recombinant Proteins; D004917:Erythromycin; D014640:Vancomycin; D001089:Arabinose