BACKGROUND Despite evidence that altered membrane porins may impair microbial drug uptake thereby potentially compounding efflux pump-mediated multidrug resistance, few studies have evaluated gene transcription to identify multidrug-resistance-associated porins and other potential drug targets. METHODS Genes that encode six membrane porins (fadL, lamB, ompC, ompF, ompW and yiaT) and two membr...

BACKGROUND One of the most important resistance mechanisms in bacteria is the increased expression of multidrug efflux pumps. To combat efflux-related resistance, the development of new efflux pump inhibitors is essential. MATERIALS AND METHODS Ten phosphorus ylides were compared based on their MDR-reverting activity in multidrug efflux pump system consisting of the subunits acridine-resistan...

Objective: Overexpression of AcrAB-TolC protein complex is often associated with the virulence of multidrug-resistant bacteria. Development of an effective efflux pump inhibitors (EPI) can be a major strategy to enhance the effectivity of current antibiotics and to restrain the menace of antibiotic resistance among bacteria. Molecular docking based assessment of anticancer drugs as EPI with com...

This study aimed to investigate the properties of mutations of the active efflux pump genes acrA/B and tolC in Escherichia coli CVCC 1547 when induced by different drugs. The mutations were isolated in vitro by exposing E. coli CVCC 1547 to stepwise increases in the concentration of ceftriaxone (CRO), amikacin (AMK), or ciprofloxacin. The results showed that the minimum inhibitory concentration...

INTRODUCTION Infectious bovine keratoconjunctivitis (IBK) is an important ocular disease which affects cattle worldwide. To advance towards IBK effective prevention and treatment strategies, it is important to define the distribution and genetic diversity of potential virulence factors present in M. bovis and M. bovoculi. The objective of this work was to identify and to analyze Moraxella spp. ...

Colicin V (ColV) is peptide antibiotic secreted by Escherichia coli through a dedicated exporter composed of three proteins, CvaA, CvaB, and TolC. ColV secretion is independent of the E. coli general secretory pathway (Sec) but requires an N-terminal export signal specific for the CvaAB/TolC exporter. ColV secretion was characterized using genetic and biochemical methods. When the ColV N-termin...

The toxin HlyA is exported from Escherichia coli, without a periplasmic intermediate, by a type I system comprising an energized inner-membrane (IM) translocase of two proteins, HlyD and the traffic ATPase HlyB, and the outer-membrane (OM) porin-like TolC. These and the toxin substrate were expressed separately to reconstitute export and, via affinity tags on the IM proteins, cross-linked in vi...

As a representative fluoroquinolone antibacterial, ciprofloxacin is frequently used to treat infections caused by bacteria such as E. coli. It is much meaningful to explore ciprofloxacin susceptibility and investigate a possible mechanism of drug susceptibility changes in E. coli ATCC25922 exposed to the environmental stress of simulated microgravity. The subculture of E. coli lasted for 7 days...

The AcrAB system of Escherichia coli is a multidrug efflux system composed of an RND-type transporter AcrB and a periplasmic accessory protein AcrA, and pumps out a wide variety of lipophilic and amphiphilic inhibitors directly into the medium, presumably through the TolC outer membrane channel. AcrA, a highly elongated protein, is thought to bring the outer and inner membranes closer. It forms...

Extracellular electron transfer can play an important role in microbial respiration on insoluble minerals. The humic acid analog anthraquinone-2,6-disulfonate (AQDS) is commonly used as an electron shuttle during studies of extracellular electron transfer. Here we provide genetic evidence that AQDS enters Shewanella oneidensis strain MR-1 and causes cell death if it accumulates past a critical ...