Calcium ions in the external medium stabilize the resting state of voltage-dependent channels, including Na channels. This effect of calcium on channel gating is usually explained in terms of the surface charge hypothesis, which proposes that local adsorption of calcium ion to the outside of the membrane alters the intramembranous electric field, thus influencing channel behavior indirectly. Ca...

In this study we examined changes in magnesium and calcium ion concentrations depending on Zebra Mussel biomass, pH values and temperature. We performed field experiments in years with different weather conditions using twelve 200 litre polycarbonate containers filled with 150 litres of non-filtered water from lowland, eutrophic reservoirs. Three treatments of the experiment were represented by...

statement of problem: dental caries is one of the most common chronic diseases in children. the balance between demineralization and remineralization of the decayed teeth depends on the calcium and phosphate content of the tooth surface. therefore, if a product such as casein phospho peptides - amorphous calcium phosphate (cpp- acp) which can significantly increase the availability of calcium a...

Calcium to calcium exchange between intracellular and extracellular pools has been imaged directly in individual cells using stable 44Ca (98.78% enrichment) in the nutrient medium and an isotopic imaging technique, ion microscopy. Observations were made by imaging mass 40 to determine the native intracellular calcium (40Ca), and mass 44 to localize the 44Ca from the extracellular medium that ex...

Ion channel selectivity is essential for their function, yet the molecular basis of a channel's ability to select between ions is still rather controversial. In this work, using a combination of molecular dynamics simulations and electrophysiological current measurements we analyze the ability of the NaChBac channel to discriminate between calcium and sodium. Our simulations show that a single ...

Structure-function studies have shown that it is possible to convert a sodium channel to a calcium-selective channel by a single amino acid substitution in the selectivity filter locus. Ion permeation through the "model selectivity filter" was modeled with a reduced set of functional groups representative of the constituent amino acid side chains. Force-field minimizations were conducted to obt...

The amino-terminal regulatory domain of cardiac troponin C (cNTnC) plays an important role as the calcium sensor for the troponin complex. Calcium binding to cNTnC results in conformational changes that trigger a cascade of events that lead to cardiac muscle contraction. The cardiac N-terminal domain of TnC consists of two EF-hand calcium binding motifs, one of which is dysfunctional in binding...

Disc-shaped bicelles are formed by mixing long-chain lipids with short-chain lipids at suitable molar ratios and they have a relatively uniform size, typically around a few tens of nanometers in diameter. Different from the typically formulated cationic or anionic liposome–DNA complexes, which are used as nonviral vectors for improving the transfection efficiency of gene therapy, a novel way of...