Immediately upstream from and adjacent to the oprP gene, which codes for the phosphate-specific porin OprP of Pseudomonas aeruginosa, lies the PR region (oprO), which cross-hybridizes with oprP DNA. To determine the function of this region, the oprO gene was expressed behind the lactose promoter in Escherichia coli, and the resultant OprO protein was purified and reconstituted into planar lipid...

The outer membrane-spanning (Oms) proteins of Borrelia burgdorferi have been visualized by freeze-fracture analysis but, until recently, not further characterized. We developed a method for the isolation of B. burgdorferi outer membrane vesicles and described porin activities with single-channel conductances of 0.6 and 12.6 nS in 1 M KCI. By using both nondenaturing isoelectric focusing gel ele...

We performed transposon mutagenesis of a two-color fluorescent reporter strain to identify new regulators of the porin genes ompF and ompC in Escherichia coli. Screening of colonies by fluorescence microscopy revealed numerous mutants that exhibited interesting patterns of porin expression. One mutant harbored an insertion in the gene encoding the histidine kinase CpxA, the sensor for a two-com...

Two clinical isolates of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae were noted to be less susceptible than expected to imipenem. Both were missing outer membrane proteins that serve as channels for antibiotic entry. The role of beta-lactamase in resistance was investigated by eliminating the original ESBL and introducing plasmids encoding various ESBLs and AmpC beta...

BACKGROUND Multidrug-resistant Pseudomonas aeruginosa has emerged as one of the most important healthcare-associated pathogens. Colistin is regarded as the last-resort antibiotic for multidrug-resistant Gram-negative bacteria, but is associated with high rates of acute kidney injury. The aim of this in vitro study is to search for an alternative treatment to colistin for multidrug-resistant P. ...

Clinical isolates of Klebsiella pneumoniae resistant to carbapenems are being isolated with increasing frequency. Loss of the expression of the major nonspecific porins OmpK35/36 is a frequent feature in these isolates. In this study, we looked for porins that could compensate for the loss of the major porins in carbapenem-resistant organisms. Comparison of the outer membrane proteins from two ...

The neisserial porin P.I is a GTP binding protein that forms a voltage-gated channel that translocates into mammalian cell membranes and modulates host cell signaling events. Here, we report that P.I confers invasion of the bacterial pathogen Neisseria gonorrhoeae into Chang epithelial cells and that this event is controlled by GTP, as well as other phosphorus-containing compounds. Bacterial in...

Gram-negative bacteria cause the majority of highly drug-resistant bacterial infections. To cross outer membrane complex cell envelope, antibiotics permeate through porins, trimeric channel proteins that enable exchange small polar molecules. Mutations in porins contribute to development phenotypes. In this work, we show a single point mutation porin PorB from Neisseria meningitidis, causative ...

Antimicrobial Susceptibility Pattern and Mutations of Outer Membrane Porin in Clinical Isolates Klebsiella pneumoniae