Washing of corn root tissue increases the electrical potential difference, negative inside, across the membranes of epidermal cells. There is no lag period in the development of the extra potential, and the entire increase is electrogenic as evidenced by collapse with the uncoupler, (p-trifluoromethoxy)-carbonyl cyanide-phenylhydrazone.Proton extrusion by the tissue declines with washing but ca...

Fluoroquinolone resistance is mainly caused by mutations in quinolone resistance-determining regions of DNA gyrase and topoisomerase IV in Escherichia coli. The AcrAB-TolC efflux pump contributes to resistance against fluoroquinolone and other antimicrobials. In this study, we investigated a high-level mechanism of fluoroquinolone resistance in E. coli that was isolated from human clinical samp...

Eleven multidrug-resistant Escherichia coli isolates (comprising 6 porcine and 5 bovine field isolates) displaying fluoroquinolone (FQ) resistance were selected from a collection obtained from the University Veterinary Hospital (Dublin, Ireland). MICs of nalidixic acid and ciprofloxacin were determined by Etest. All showed MICs of nalidixic acid of >256 μg/ml and MICs of ciprofloxacin ranging f...

Factors modifying calcium efflux from rabbit skeletal muscle sarcoplasmic reticulum vesicles were examined after phosphate-supported calcium uptake reached steady state. Increasing external Ca”+ promoted calcium efflux by a mechanism that exhibited Michaelis-Menten kinetics; V,,, at 25” with 5 mM MgATP as substrate and 50 mM phosphate as calcium-precipitating anion was -400 nmol/mg/min and the ...

Efflux pump inhibitors are of great interest since their use as adjuvants of bacterial chemotherapy can increase the intracellular concentrations of the antibiotics and assist in the battle against the rising of antibiotic-resistant bacteria. In this work, we have described the mode of action of the 2-phenylquinoline efflux inhibitor (4-(2-(piperazin-1-yl)ethoxy)-2-(4-propoxyphenyl) quinolone -...

p-glycoprotein (p-gp) is a trans-membrane drug efflux pump. several drugs are p-gp substrates. some drugs may affect the activity of p-gp by inhibiting its function, resulting in significant drug-drug interactions (ddis). it is critical to understand which drugs are inhibitors of p-gp so that adverse ddis can be minimized or avoided. this study investigated the effects of gliclazide, metformin,...

In bacteria, multidrug-resistance pumps (MDRs) confer resistance to chemically unrelated amphipathic toxins. A major challenge in developing efficacious antibiotics is identifying antimicrobial compounds that are not rapidly pumped out of bacterial cells. The plant antimicrobial berberine, the active component of the medicinal plants echinacea and golden seal, is a cation that is readily extrud...

Reduced susceptibility to antimicrobials in Gram-negative bacteria may result from multiple resistance mechanisms, including increased efflux pump activity or reduced porin protein expression. Up-regulation of the efflux pump system is closely associated with multidrug resistance (MDR). To help investigate the role of efflux pumps on compound accumulation, a fluorescence-based assay was develop...

Background: For understanding the roles of fatty acids on the induction of acrosome reaction which occurs under association of cholesterol efflux and PKA or PKC pathways in boar spermatozoa, metabolic fate of alone and combined radiolabeled 14C-oleic acid and 3H-linoleic acid incorporated in the sperm was compared, and behavior of cholesterol and effects of PKA and PKC inhibitors upon fatty aci...