Allosteric regulation by cytosolic Ca2+ of Na(+)/Ca2+ exchange activity in the Ca2+ efflux mode has received little attention because it has been technically difficult to distinguish between the roles of Ca2+ as allosteric activator and transport substrate. In this study, we used transfected Chinese hamster ovary cells to compare the Ca2+ efflux activities in nontransfected cells and in cells e...

1. An electrophysiological method was used to estimate the half-times for sodium and potassium entry to, and efflux from, the extra-axonal space in peripheral nerve and central nervous connectives of two species of crustacean. Results from crab (marine) and crayfish (fresh water) were qualitatively similar. 2. Peripheral nerve showed no evidence for diffusion barriers, potassium entry and efflu...

Escherichia coli is one of the most frequent causes of urinary tract infections. Efflux system overexpression is reported to contribute to E. coli resistance to several antibiotics. Our aim in this study was to investigate the relation between antibiotic resistance and the expression of the efflux pump genes acrA and mdfA in E. coli by real-time reverse transcription-PCR. We tested the in vitro...

A method is described for investigating the rate of loss of water and carbon dioxide from terrestrial insects by absorbing tritiated water and 14CO2 from a gas stream flowing past the insect. The loss of water and carbon dioxide can be studied simultaneously with a time resolution (nominal) down to 2 min. The theoretical and experimental bases of analysing the data are considered in detail. The...

Abstract Tripartite efflux pumps built around ATP-binding cassette (ABC) transporters are membrane protein machineries that perform vectorial export of a large variety drugs and virulence factors from Gram negative bacteria, using ATP-hydrolysis as energy source. Determining the number ATP molecules consumed per transport cycle is essential to understanding efficiency substrate transport. Using...

The present study aimed at exploring the potential of the P-glycoprotein (P-gp) transporters as a barrier to the repaglinide (REG) epithelial permeability. In-vitro intestinal absorption models, the everted gut sac, and Caco-2 cell line, were used to study the possible role of P-gp in intestinal transport of REG. In the everted gut sacs, apparent permeability coefficients showed cargo concentra...

The adeH and adeS Efflux Pump Genes in Imipenem Colistin-Resistant Acinetobacter baumannii Clinical Isolates

Carbonates in soils may act as a potential source of CO? efflux from calcareous to the atmosphere. However, its seasonal dynamics and relationships with soil temperature or moisture are not well?understood. A 5?yr warming experiment was performed evaluate effects symmetric (all season) asymmetric (seasonal) on organic fraction (SOC)?derived carbonate?derived (partitioned by ?¹³C signature) kars...