Biogenic manganese oxides (BMOs) formed in a culture of the Mn(II)-oxidizing fungus Acremonium strictum strain KR21-2 are known to retain enzymatic Mn(II) oxidation activity. Consequently, these increasingly attracting attention as substrate for eliminating toxic elements from contaminated wastewaters. In this study, we examined Ba2+ sequestration potential enzymatically active BMOs with and wi...

A peralkaline granite of the Ilimaussaq Complex, South Greenland, contains rare mineral henrymeyerite [(Ba0.92Na0.05Ca0.03)1.0(Ti6.87Fe2+1.04Nb0.03)7.9O16], a low-Fe Ba titanate [(Ba0.74Ca0.02Na0.05)0.8 (Ti4.9oFe2+0.15Nb0.04)5.1O11], and an unidentified titanosilicate. Both titanates show coupled substitution 2Na+ + Si4+ → Ba2+ Ti4+. The minerals are present as tiny crystals fringing ilmenite i...

In the context of designing efficient photocontrolled ion-release systems, we propose a ”simple” computational strategy able to predict cation photoejection. Our is based on TD-DFT calculations and analysis charge transfer (CT) parameters excited states that can be populated for given excitation wavelength, in Franck–Condon region. With help CT descriptors (the variation electronic density, so-...

Arterial potassium permeability is increased in hypertension. In this study we conducted voltage-clamp experiments to determine whether the whole-cell K+ current is increased in a Ca(2+)-dependent manner in aortic smooth muscle cells from stroke-prone spontaneously hypertensive rats (SHRSP). Aortic cells from Wistar-Kyoto (WKY) rats and SHRSP demonstrated an outward rectifying current elicited ...

Members of the Kir2 subfamily of inwardly rectifying K+ channels characterized by their strong current rectification are widely expressed both in the periphery and in the CNS in mammals. We have cloned from rat brain a fourth subfamily member, designated Kir2.4 (IRK4), which shares 53-63% similarity to Kir2.1, Kir2.2, or Kir2.3 on the amino acid level. In situ hybridization analysis identifies ...

Potassium channels are ubiquitous, being present in all living organisms. These proteins share common structural elements, which confer common functional features. In general, all K+ channels have a high selectivity for K+, and are blocked by cations of similar dimensions, such as Cs+ and Ba2+. Mutations in the pore region tend to lead to either the total loss of function or K+ selectivity. We ...

We investigated membrane currents activated by intracellular divalent cations in two types of molluscan pacemaker neurons. A fast and quantitative pressure injection technique was used to apply Ca2+ and other divalent cations. Ca2+ was most effective in activating a nonspecific cation current and two types of K+ currents found in these cells. One type of outward current was quickly activated fo...

The mode of inhibition of the phospholipase A2 (PLA2) enzyme from the Chinese cobra (Naja naja atra) by Zn2+ is qualitatively different from inhibition by Ba2+. Inhibition by Ba2+ shows the kinetic characteristics of a conventional competitive inhibitor acting to displace Ca2+ from a single essential site, but Zn2+ has the paradoxical property of being more inhibitory at high than at low Ca2+ c...

Most of the whole-cell calcium current of frog sympathetic neurons is an N-type current, blocked by omega-conotoxin GVIA (omegaCGVIA). Thus, these cells should be an excellent system to study the properties of single N-type channels. However, a channel that is active near -10 mV in isotonic Ba2+, originally identified as "N-type," corresponds more closely to a omegaCGVIA-resistant component of ...