Peculiarities of Structure, Polymorphism, and Resistance to Oxidation of Fish Hemoglobins

The paper presents data on peculiarities of structural organization of fish hemoglobin molecules. The existence of symmetric and asymmetric complexes and their importance for formation in some types of complex heterogeneous hemoglobin systems is considered. The comparative characteristics of the primary structure of - and -chains of the respiratory pigments in higher and lower vertebrates are presented. The causes of low resistance of fish hemoglobins to oxidation are discussed. Protective action of Cl^– under conditions of nitrite intoxication, as well as role of several intraerythrocytic molecular systems in maintaining the pigment ferroform (superoxide dismutase, catalase, peroxidase, and NADH-diaphorase) are considered.     

New Molecular Determinant for Inactivation of the Human L-Type α1C Ca2+ Channel

Molecular cloning of the human fibroblast Ca²⁺ channel pore-forming α_1C subunit revealed (Soldatov, 1992. Proc. Natl. Acad. Sci. USA 89:4628-4632) a naturally occurring mutation g²²⁵⁴→ a that causes the replacement of the conservative alanine for threonine at the position 752 at the cytoplasmic end of transmembrane segment IIS6. Using stably transfected HEK293 cell lines, we have compared electrophysiological properties of the conventional α_1C,77 human recombinant L-type Ca²⁺ channel with those of its mutated isoform α_1C,94 containing the A752T replacement. Comparative quantification of steady-state availability of the current carried by α_1C,94 and α_1C,77 showed that A752T mutation prevented a large (≈25%) fraction of the current carried by Ca²⁺ or Ba²⁺ from fully inactivating. This mutation, however, did not appear to alter significantly the Ca²⁺-dependence and kinetics of decay of the inactivating fraction of the current or its voltage-dependence. The data suggests that Ala752 at the cytoplasmic end of IIS6 might serve as a molecular determinant of the Ca²⁺ channel inactivation, possibly regulating the voltage-dependence of its availability. Received: 14 January 2000/Revised: 20 June 2000     

Principles of calcium signaling. Salisbury Cove, Maine, June 28-30, 2007

A three-day International Symposium entitled "Principles of Calcium Signaling" organized by James N. Weiss, Yale E. Goldman, Stéphane Hatem, Lars Cleemann and Nikolai M. Soldatov in honor of the research contributions of Professor Martin Morad was held at the Mount Desert Island Biological Laboratory, Salisbury Cove, Maine. Support for this meeting was provided in part by GlaxoSmithKline, Leica Microsystems, Nikon Corp., St. Jude Medical, Inc., UCLA Cardiac Arrhythmia Center, Dr. Donald S. Orkand, Bob Hillis Family and OML, and Mount Desert Island Biological Laboratory. The symposium featured sessions on Cardiac physiology, Ion channels and Calcium signaling.     

Identification of plasma membrane macro- and microdomains from wavelet analysis of FRET microscopy

In this study, we sought to characterize functional signaling domains by applying the multiresolution properties of the continuous wavelet transform to fluorescence resonance energy transfer (FRET) microscopic images of plasma membranes. A genetically encoded FRET reporter of protein kinase C (PKC)-dependent phosphorylation was expressed in COS1 cells. Differences between wavelet coefficient matrices revealed several heterogeneous domains (typically ranging from 1 to 5 microm), reflecting the dynamic balance between PKC and phosphatase activity during stimulation with phorbol-12,13-dibutyrate or acetylcholine. The balance in these domains was not necessarily reflected in the overall plasma membrane changes, and observed heterogeneity was absent when cells were exposed to a phosphatase or PKC inhibitor. Prolonged exposure to phorbol-12,13-dibutyrate and acetylcholine yielded more homogeneous FRET distribution in plasma membranes. The proposed wavelet-based image analysis provides, for the first time, a basis and a means of detecting and quantifying dynamic changes in functional signaling domains, and may find broader application in studying fine aspects of cellular signaling by various imaging reporters.     

Participation of dihydropyridine-sensitive calcium channels in psychotropic effects of nootropic drugs

Administration of Ca-entry blockers with different chemical structure before the braining sessions produced the reduction of memory retention in mice and rats in the one-trial passive avoidance tests. This effect was absent in animals treated immediately after training test. Nootropic drugs piracetam and oxiracetam corrected the retention of memory when injected just after training test. Chronic treatment of rats with increasing doses of the nootropic drugs produced about two-fold tissue-specific elevation in the density of DHP-receptors, associated with L-type Ca-channels in synaptosomal membranes of rat cerebral cortex. Maximal effect was observed in a dose of 10 mg/kg. Diltiazem, administrated in a dose of 10 mg/kg, produced about two-fold decrease in the receptors density measured 24 hrs after the first injection. Oxiracetam (10 mg/kg) completely antagonized the effect of Ca-entry blocker. These data imply that nootropic action of piracetam and oxiracetam is mediated by L-type Ca-channels.     

Distribution Function of Relativistic Electrons Produced by the Tunneling Ionization of a Gas by an Intense Electromagnetic Wave

The distribution function of the relativistic electrons produced in the interaction between an intense electromagnetic wave and a neutral gas is derived and is shown to be nonequilibrium and anisotropic. The drift plasma current is calculated, and the applicability conditions for the results obtained are determined.     

Mice in Bion-M 1 Space Mission: Training and Selection

After a 16-year hiatus, Russia has resumed its program of biomedical research in space, with the successful 30-day flight of the Bion-M 1 biosatellite (April 19–May 19, 2013). The principal species for biomedical research in this project was the mouse. This paper presents an overview of the scientific goals, the experimental design and the mouse training/selection program. The aim of mice experiments in the Bion-M 1 project was to elucidate cellular and molecular mechanisms, underlying the adaptation of key physiological systems to long-term exposure in microgravity. The studies with mice combined in vivo measurements, both in flight and post-flight (including continuous blood pressure measurement), with extensive in vitro studies carried out shortly after return of the mice and in the end of recovery study. Male C57/BL6 mice group housed in space habitats were flown aboard the Bion-M 1 biosatellite, or remained on ground in the control experiment that replicated environmental and housing conditions in the spacecraft. Vivarium control groups were used to account for housing effects and possible seasonal differences. Mice training included the co-adaptation in housing groups and mice adaptation to paste food diet. The measures taken to co-adapt aggressive male mice in housing groups and the peculiarities of “space” paste food are described. The training program for mice designated for in vivo studies was broader and included behavioral/functional test battery and continuous behavioral measurements in the home-cage. The results of the preliminary tests were used for the selection of homogenous groups. After the flight, mice were in good condition for biomedical studies and displayed signs of pronounced disadaptation to Earth''s gravity. The outcomes of the training program for the mice welfare are discussed. We conclude that our training program was effective and that male mice can be successfully employed in space biomedical research.