Composition and content of carotenoids in body of the Black sea gastropod Rapana venosa (Valenviennes, 1846)

The composition and content of carotenoids were studied in the body of Black sea gastropod Rapana venosa. The methods of thin layer and high performance liquid chromatography, mass-spectra and the spectra in UV-VIS diapason were used for isolation and identification of compounds belonging to this group. 84–87% of carotenoids were identified. The main part of them is presented by mytiloxanthin—28–30%. Other—pectenolon, diatoxanthin, alloxanthin—composed 10–15% of total content, with exception of β-carotene—3–4%. The fraction containing complex esters of pectenolon, diatoxanthin, alloxanthin and mytiloxanthin was also isolated. It composes 17–20% of the pigments of carotene row. The minor components were not determined. Study discusses the pathways of carotenoid metabolic transformation in the R. venosa tissues studying trophic system “mollusc-filter—mollusc-predator” on examples of Mytilus galloprovincialis and R. venosa.     

Forecasting possible changes in zonal vegetation boundaries in European Russia and Western Siberia in connection with global warming

This paper discusses the relationships of zonal vegetation boundaries with some climatic indicators. Possible changes in subzonal vegetation boundaries in the territory of European Russia and Western Siberia are forecasted within the framework of one of the global warming scenarios. The revealed regularities make it possible to suggest a mathematical cartographic model of vegetation zonality for the 2046–2065 period.     

Dynamic parameters of the dipole layer formed during pulsed photoemission discharging of a plane vacuum diode

The parameters of the current and dipole moment that arise during the discharging of a plane vacuum diode by a short photoemission pulse are studied analytically and numerically. Electron emission is induced by the ionizing radiation incident obliquely on the cathode. An approximate analytic model is developed that, under certain conditions, makes it possible to reduce the problem to that having a known solution for the normally incident ionizing radiation. In the case of a short pulse, scaling relationships for the parameters of the dipole layer are obtained as functions of the diode parameters (the interelectrode gap and applied voltage) and the angle of incidence of the ionizing radiation.     

Differential role of the alpha1C subunit tails in regulation of the Cav1.2 channel by membrane potential, beta subunits, and Ca2+ ions

Voltage-gated Ca(v)1.2 channels are composed of the pore-forming alpha1C and auxiliary beta and alpha2delta subunits. Voltage-dependent conformational rearrangements of the alpha1C subunit C-tail have been implicated in Ca2+ signal transduction. In contrast, the alpha1C N-tail demonstrates limited voltage-gated mobility. We have asked whether these properties are critical for the channel function. Here we report that transient anchoring of the alpha1C subunit C-tail in the plasma membrane inhibits Ca2+-dependent and slow voltage-dependent inactivation. Both alpha2delta and beta subunits remain essential for the functional channel. In contrast, if alpha1C subunits with are expressed alpha2delta but in the absence of a beta subunit, plasma membrane anchoring of the alpha1C N terminus or its deletion inhibit both voltage- and Ca2+-dependent inactivation of the current. The following findings all corroborate the importance of the alpha1C N-tail/beta interaction: (i) co-expression of beta restores inactivation properties, (ii) release of the alpha1C N terminus inhibits the beta-deficient channel, and (iii) voltage-gated mobility of the alpha1C N-tail vis a vis the plasma membrane is increased in the beta-deficient (silent) channel. Together, these data argue that both the alpha1C N- and C-tails have important but different roles in the voltage- and Ca2+-dependent inactivation, as well as beta subunit modulation of the channel. The alpha1C N-tail may have a role in the channel trafficking and is a target of the beta subunit modulation. The beta subunit facilitates voltage gating by competing with the N-tail and constraining its voltage-dependent rearrangements. Thus, cross-talk between the alpha1C C and N termini, beta subunit, and the cytoplasmic pore region confers the multifactorial regulation of Ca(v)1.2 channels.     

Direct comparison of turbulence measurements by Langmuir probe technique and by reflectometry

A comparative analysis of the experimental results from two diagnostic methods—reflectometry and Langmuir probe technique—is carried out, and advantages and drawbacks of these methods are considered; in particular, a comparison is made between their spectral characteristics. The problems arising in interpreting the experimental reflectometric results are thoroughly discussed. To resolve these problems, a stochastic turbulence model with statistical, spectral, and correlation turbulent plasma properties close to the measured ones is constructed. The model is used to simulate the propagation of an electromagnetic wave in a model turbulent plasma. A comparison of the numerical results with the experimental data shows a high spatial locality of reflectometric measurements.     

Effect of hypoxia on the content and stoichiometry of cytochromes in muscle of the gray mullet Liza aurata

The maintenance of the gray mullet Liza aurata under conditions of hypoxia ( $ P_{O_2 } The maintenance of the gray mullet Liza aurata under conditions of hypoxia ( 55–82 GPa) for 1–2 days led to a decrease of oxygen tension in arterial blood by 47%, while in venous blood—by 28%. The mean muscle oxygen tension decreased by 19.2%. The number of hypoxic and anoxic zones in muscle tissue decreased significantly, in particular in red muscle. The maintenance of the fish in hypoxic waters for 15 days led to a rise of the content of cytochromes in muscle and a qualitative readjustment of the mitochondrial respiratory chain manifested in an increase of the content of cytochromes a and a3 and a decrease of cytochrome b. In discussion, literature data are presented which support the described regularity. Original Russian Text ? A. A. Soldatov, M. V. Savina, 2008, published in Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, 2008, Vol. 44, No. 5, pp. 508–512.     

State of the antioxidant enzyme complex of tissues of the Black Sea mollusc Mytilus galloprovincialis under conditions of natural oxidative stress

The state of the antioxidant (AO) system (AOS) and the content of products of lipid peroxidation (LPO) in hepatopancreas, gill, and foot of the Black Sea mollusc Mytilus galloprovincialis Lam. were studied in norm and under conditions of natural oxidative stress (spawning). It has been established that under conditions of spawning, the AO-protection of hepatopancreas cells is predominantly oriented to inactivation of high concentrations of peroxide compounds with participation of glutathione peroxidase and catalase. In the foot tissue, on the contrary, the main role in AO-processes is played by enzymatic inhibition of superoxide anionradical with aid of superoxide dismutase. The highest level of oxidative stress in the spawning state is revealed in the mollusc gill, which is indicated by the maximal increase of the content of TBK-active products.     

Peculiarities of Organization and Functioning of the Fish Red Blood System

The review presents information on localization of sites of erythropoiesis in the fish organism, morphological peculiarities and proliferative activity of erythroid elements at different stages of differentiation, and life span of circulating erythrocytes. Data about effects of various factors on production of erythrocytes by hemopoietic tissue, such as erythropoetin and several other biologically active substances, are presented. Peculiarities are considered of organization of fish spleen as an organ storing and destroying old erythroid forms. Significance of production and destruction processes in the red blood system in correction of erythrocytic homeostasis in the fish organism is discussed.__________Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 3, 2005, pp. 217–223.Original Russian Text Copyright © 2005 by Soldatov.