Optimal conditions for preservation of isolated heart using creatine phosphate and vitamin E (an experimental study)

Functional and structural safety of the myocardium following 6-hour preservation at 4-6 degrees C in ion-balanced cardioplegic solution alone or in combination with pharmacological corrective was evaluated in rats. Langendorff and Neely model of isolated heart perfusion was used. The addition of creatine phosphate in a conservation of 10 mM/l to the solution or donor pretreatment with 70 mg/kg vitamin E was found to potentiate the protective properties of the solution under deep hypothermia. The combined use of the agents proved to warrant the initial intact structural and functional status of the rat myocardium.     

Effect of adenosine on hemodynamic changes during the development of neurogenic myocardial lesions

The influence of adenosine on hemodynamic changes induced by electrostimulation of reflexogenic zone of aorta was studied in this article. It was shown that 3-hour electrostimulation increased the total peripheral resistance and decreased cardiac output and aortic pressure. Intravenous infusion of adenosine during electrostimulation led to the normalization of main indices of hemodynamics.     

Two spreading states of human embryo mesenchymal cells in vitro

Spreading of mesenchymal cells of human embryo on plastic and on type I collagens (from rat, sheep, and ox) was studied. Spreading of the cells on collagens was stronger than that in control, but no differences between different collagens were revealed. The cell perimeter, the spreading coefficient, and the cell projection area on the substrate were used as morphometric parameters. The spreading of cells was monitored for 0.5–2 h after plating. During the spreading both on plastic and on collagen, groups of small cells were revealed as separate subpopulations. As a whole, such cells accounted for 9% of the cell population in control and for 2% in experiment. We assume that this cell type is associated with a special independent functional state of the cells that precedes cell spreading.     

Biochemical characteristics of the Ca2+ pumping ATPase in the peribacteroid membrane from broad bean root nodules

Ca²⁺-ATPase in the peribacteroid membrane (PBM) of symbiosomes isolated from Vicia faba root nodules was characterized in terms of its hydrolytic and transport activities. Both activities were found to be pH-dependent and exhibit pH optimum at pH 7.0. Translocation of Ca²⁺ through the PBM by the Ca²⁺-ATPase was shown to be fueled by ATP and other nucleotide triphosphates in the following order: ATP?>?ITP???GTP???UTP???CTP, the K _m of the enzyme for MgATP being about 100 μM. Ca-dependent ITP-hydrolytic activity of symbiosomes was investigated in the presence of the Ca-EGTA buffer system and showed the affinity of PBM Ca²⁺-ATPase for Ca²⁺ of about 0.1 μM. The transport activity of Ca²⁺-ATPase was inhibited by erythrosin B as well as orthovanadate, but markedly stimulated by calmodulin from bovine brain. These results allowed us to conclude that this enzyme belongs to IIB-type Ca²⁺-ATPases which are present in other plant membranes.     

Interannual Variability of Low-Molecular Metabolite Composition in <Emphasis Type="Italic">Ceratophyllum demersum</Emphasis> (Ceratophyllaceae) from a Floodplain Lake with a Changeable Trophic Status

The regularities that shape the composition of low molecular weight organic compounds (LMWOCs) in aquatic macrophytes in response to aquatic environment alterations remain poorly characterized. The aim of the present study consists of a comparative interannual investigation into LMWOC composition in rigid hornwort (Ceratophyllum demersum L.) from a Volga-Akhtuba floodplain lake with a variable trophic state. A high variability of LMWOC composition and individual compound levels in hornwort is detected as different trophic states of the water body are analyzed. Active allelochemicals are the predominant LMWOCs in the case of a “macrophytic” mesotrophic state of the lake, with fatty acids (the free fatty acid fraction) apparently being the most important in this group. Hornwort LMWOC composition in the case of a “cyanobacterial” eutrophic type of lake development is characterized by the predomination of compounds that enhance the protective reactions (manool being the most important) under the conditions of suppression by cyanobacteria, which is also manifested as an almost twofold decrease in the overall intensity of organiccompound biosynthesis.     

Adapting Agricultural Water Use to Climate Change in a Post-Soviet Context: Challenges and Opportunities in Southeast Kazakhstan

The convergence of climate change and post-Soviet socio-economic and institutional transformations has been underexplored so far, as have the consequences of such convergence on crop agriculture in Central Asia. This paper provides a place-based analysis of constraints and opportunities for adaptation to climate change, with a specific focus on water use, in two districts in southeast Kazakhstan. Data were collected by 2 multi-stakeholder participatory workshops, 21 semi-structured in-depth interviews, and secondary statistical data. The present-day agricultural system is characterised by enduring Soviet-era management structures, but without state inputs that previously sustained agricultural productivity. Low margins of profitability on many privatised farms mean that attempts to implement integrated water management have produced water users associations unable to maintain and upgrade a deteriorating irrigation infrastructure. Although actors engage in tactical adaptation measures, necessary structural adaptation of the irrigation system remains difficult without significant public or private investments. Market-based water management models have been translated ambiguously to this region, which fails to encourage efficient water use and hinders adaptation to water stress. In addition, a mutual interdependence of informal networks and formal institutions characterises both state governance and everyday life in Kazakhstan. Such interdependence simultaneously facilitates operational and tactical adaptation, but hinders structural adaptation, as informal networks exist as a parallel system that achieves substantive outcomes while perpetuating the inertia and incapacity of the state bureaucracy. This article has relevance for critical understanding of integrated water management in practice and adaptation to climate change in post-Soviet institutional settings more broadly.     

Ca<Superscript>2+</Superscript>-ATPase in the symbiosome membrane from broad bean root nodules: further evidence for its functioning as ATP-driven Ca<Superscript>2+</Superscript>/H<Superscript>+</Superscript> exchanger

To date, it has been established that the symbiosome membrane (SM), i.e., plant-derived membrane of symbiosomes, nitrogen-fixing compartments of legume root nodules, is equipped with Ca²⁺-ATPase transporting Ca²⁺ ions through the SM from the cytosol of infected cells into the symbiosome space (SS). Earlier in the experiments on the SM vesicles isolated from broad bean root nodules some data indicating the action of the Ca²⁺-ATPase as ATP-driven Ca²⁺/H⁺ antiporter were obtained. In the present work performed on isolated symbiosomes from the same plant object, further evidence in favor of calcium-proton countertransport mechanism of the pump operation was obtained. These were expressed in vanadate-sensitive alkalinization of the SS coupled with Ca²⁺ uptake by symbiosomes catalyzed by the SM Ca²⁺-ATPase, stimulation of the kinetics of the latter process in the response to artificial acidification of the SS and expectable modulation of ITP-hydrolyzing activity of this enzyme caused by the variation of pH within this compartment. The above findings are discussed in the framework of the model describing the mechanism of Ca²⁺-ATPase operation as an ATP-driven Ca²⁺/H⁺ exchanger and on this base allow us to put forward the hypothesis about the involvement of this enzyme in symbiosome signaling in a Ca²⁺- and pH-dependent manner.     

Effect of nickel chloride on seed germination and morphophysiological parameters of seedlings of <Emphasis Type="Italic">Alisma plantago-aquatica</Emphasis> L. and <Emphasis Type="Italic">Sium latifolium</Emphasis> L.

The effect of nickel chloride concentrations in the range of 1–1000 mg/L on seed germination and the development of organs and pigment system in seedlings of the helophyte common water-plantain Alisma plantago-aquatica L. and hygrohelophyte greater water-parsnip Sium latifolium L. has been studied. It is shown that nickel chloride has practically no effect on the germination of the common water-plantain; however, it suppresses the germination of the greater water-parsnip. It is demonstrated that the toxicant suppresses the growth of seedlings and synthesis of photosynthetic pigments. The length of cotyledons and hypocotyl is less variable, with a much stronger effect on roots and leaves. It is determined that the morphometric parameters are less sensitive to the toxicant when compared to physiological ones. In general, the common water-plantain is more resistant to the effect of nickel chloride than the greater water-parsnip.