α-Hemolysin is synthesized as a 1024-amino acid polypeptide, then intracellularly activated by specific fatty acylation. A second activation step takes place in the extracellular medium through binding of Ca2+ ions. Even in the absence of fatty acids and Ca2+ HlyA is an amphipathic protein, with a tendency to self-aggregation. However, Ca2+-binding appears to expose hydrophobic patches on the p...

The microelectrophoresis technique was used to determine the dependence of human erythrocyte surface potential on the concentration of various cations and anions. The interpretation of the results is based on the Gouy--Chapman--Stern theory. Values of pK, characterizing the binding of ions to the external surface of erythrocytes, as well as numbers of binding sites per unit area were determined...

Depolarization of membrane potential by high external K+ activates Ca2+ influx via voltage-dependent Ca2+ channels in GH4C1 cells (Tan, K.-N., and Tashjian, A. H., Jr. (1983) J. Biol. Chem. 258, 418-426). The involvement of this channel in thyrotropin-releasing hormone (TRH) action on prolactin (PRL) release was assessed by comparing the pharmacological characteristics of TRH-induced PRL releas...

The inositol 1,4,5-trisphosphate receptor (InsP3R), an intracellular calcium release channel, is found in virtually all cells and is abundant in the cerebellum. We used Mn2+ as a tool to study two aspects of the cerebellar InsP3R. First, to investigate the structure of the ion pore, Mn2+ permeation through the channel was determined. We found that Mn2+ can pass through the InsP3R; the selectivi...

We have studied the interactions of Ba ion with K channels. Ba2+ blocks these channels when applied either internally or externally in millimolar concentrations. Periodic depolarizations enhance block with internal Ba2+, but diminish the block caused by external Ba2+. At rest, dissociation of Ba2+ from blocked channels is very slow, as ascertained by infrequent test pulses applied after washing...

85Sr as radioindicator has been applied to strontium separation selectivity study using cisdicyclohexano-18-crown-6 (DCH18C6) extraction agent and picric acid counter ion with the aim contribute development of a rapid method extraction. The same used for fractionation in chosen soils by application Tessier- BCR sequential procedures. Experimental results have shown, that mentioned system is app...

To study the relative roles of sodium (Na+) and calcium ions (Ca2+) in the response of adrenal glomerulosa cells, we investigated the effects of different Na+ concentrations in the incubation media and the actions of substances that interfere with Ca2+ fluxes. Basal aldosterone secretion and response to angiotensin II (AII), adrenocorticotropic hormone (ACTH), or potassium (K+) were dependent o...

(Sr, Ca, Ba)Al₂O₄:Eu2+, Dy3+ phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, Ca)Al₂O₄:Eu2+,Dy3+ phosphors, the different phase formation from monoclinic SrAl₂O₄ phase to hexagonal SrAl₂O₄ phase to monoclinic CaAl₂O₄ phase was observed when...

Lithium, declared critical raw material by the European Union in 2020, is a competitor to hydrogen as alternative petroleum. Its use increasing while reserves are declining, boosting new sources, seawater desalination concentrates. In this work, computational study of most promising extractants, β-diketones and organophosphates combinations thereof, towards lithium presence metal ions found con...

Nucleation of barite (BaSO4) has broad implications in geological, environmental, and materials sciences. While impurity metals are common, our understanding how they impact nucleation remains dim. Here, we used classical optical microscopy compared to fast X-ray nanotomography (XnT) investigate heterogeneous on silica situ with Sr2+ as an ion. The observed rates were consistent theory (CNT), w...