Activity of trypsin inhibitors in wheat seedlings exposed to pathogenic fungus Tilletia caries and phytohormones

We compared the effect of common bunt (caused by fungus Tilletia caries Tul.) and treatment with phytohormones IAA, ABA, and cytokinins (CK) on the activity of trypsin inhibitors (TI) in wheat seedlings. The experiments were conducted with pathogen-susceptible species of wheat Triticum aestivum L. (cv. Zhnitsa) and resistant species T. timopheevii Zhuk. (accession k-58666 from the collection of All-Russian Institute of Plant Industry). In the resistant wheat, the fungus elevated the activity of TI and the content of CK, whereas in the susceptible wheat, it induced accumulation of IAA. In the seedlings of wheat T. aestivum, TI activity increased under the effect of CK, same as upon the action of pathogen. ABA briefly increased the activity of TI, whereas IAA did not considerably affect it. It was concluded that among the investigated hormones, CK play a leading role in the regulation of defense responses of wheat plants involving TI.     

Morphological and functional features of the blood in humans during a nine-day stay in an oxyargon environment with various oxygen contents

Biochemical parameters of the red blood and oxygen transportation of hemoglobin by erythrocytes were studied in subjects who volunteered for chamber experiments (0.15 MPa) with normal and hypoxic oxygen-nitrogen-argon (O₂-N₂-Ar) gas environments. Erythrocyte metabolism, lipid and phospholipid spectra, and the efficiency of oxygen releasing and retention by hemoglobin were studied in the period of collecting baseline data, on the sixth day of stay in a hyperbaric normoxic O₂-N₂-Ar gas environment (13.7% O₂), on the third day of stay in a hyperbaric hypoxic O₂-N₂-Ar environment (9.9% O₂), and on the first and the tenth days of a postexperimental rehabilitation period. The high pressure, hypoxia, and the subsequent decompression resulted in a decrease in the ATP levels, which is probably due to the changes within the membrane and increased G6PD activity associated with cell repair. Changes in the lipid and phospholipid compositions of the membrane indicate an altered phase state of the plasma membrane, i.e., an increased viscosity, which may be related to possible changes in the membrane’s permeability. As a rule, hyperbaric conditions lead to a decrease in oxygen transportation in the blood of the subjects. Hypoxia against the background of hyperbaria had different effects on the subjects, namely, the absence of changes, a decrease, or an increase in the efficiency of oxygen transportation, which can be explained by the selectivity and individual sensitivity of the subjects to the experimental factors. A decrease in the efficiency of oxygen transportation by hemoglobin is most likely to be related to an increase in the viscosity of the plasma membrane, which may affect the conformation of hemoporphyrin of the membrane-bound hemoglobin and obstruct oxygen transportation through the membrane.     

The Usage of Plasmalemmal Vesicles Inverted by Brij 58 Treatment for Studying Processes,which Occur on the Cytosolic Membrane Surface

We studied the possible use of the detergent Brij 58 in physiological experiments for the reorientation of right-side-out plasmalemmal vesicles, which were isolated from wheat (Triticum aestivum L.) coleoptiles. The activities of K⁺, Mg²⁺-ATPase and the ATP-dependent H⁺-potential were higher in Brij 58-treated vesicles, whereas membrane permeability for K⁺ and Na⁺ remained unchanged. Brij 58 did not suppress the ATP-dependent IAA transport into vesicles and RNA polymerase II activation by IAA–protein plasmalemmal complexes in the system of isolated nuclei. The conclusion was that, using Brij 58, we could obtain the plasmalemmal fraction, which consisted almost completely of closed inverted vesicles. These vesicles can be applied for the in vitro study of the processes, which occur on the cytosolic plasmalemmal surface.     

Effect of weak static magnetic fields on the excitability of a neuron

Changes in the excitability of the neuron (amplitude, excitability threshold, rate of action potential transduction), as well as changes in the viscosity of the plasma membrane of the nerve and membranes of subcellular organelles, induced by the action of a weak magnetic field, have been studied by the methods of extracellular registration of membrane potential and combination scattering. It was found that only the threshold of excitability in intact nervous fibers increases by the action of this field. It was proven that the conformation of C40 carotenoids localized not only in plasma membranes but also in subcellular membranes of the neuron changes in a weak magnetic field. It is assumed that the changes in the excitability of the neuron by the action of weak magnetic field are due to changes in the orderliness of membrane lipids and the content of oxygen in the cytoplasm.     

Effects of nitric oxide on protein-lipid interactions in the membranes of the myelinated nerve fiber

The influence of nitric oxide (NO) on the myelinated nerve fiber and the impact of modification of SHgroups of axon and myelin membrane proteins on the amplitude and propagation velocity of action potential (AP), amount of the membrane-bound calcium (Ca _mb ²⁺ , viscosity of the axon membrane, and saturation factor of phospholipid fatty acids (Sf) of myelin have been investigated. We established that the decrease in the number of extracellular SH-groups in membrane proteins induced by p-chloromercuribenzoate (pCMB, 10^?4 M), led to a decrease in the AP amplitude and a reversible desorption of Ca _mb ²⁺ but did not affect the axolemma viscosity and Sf. Nitric oxide (NO) caused a decrease in the AP amplitude and propagation velocity, an increase in the axolemma viscosity and a decrease in Sf of myelin; it also induced a reversible desorption of Ca _mb ²⁺ . Pretreatment of the nerve fiber with pCMB weakened the NO-induced desorption of Pretreatment of the nerve fiber with K⁺-channel blocker tetraethylammonium (10^?2 M) completely abolished the NO-induced change in the amount of Ca _mb ²⁺ . We suppose that NO-mediated changes in axolemma viscosity, Sf of myelin and desorption of Ca _mb ²⁺ affect protein-lipid interactions in axolemma and myelin, which in their turn influence the propagation of AP.     

Environmental changes recorded in deposits of the Izyubrinye Salontsi Lake,Sikhote-Alin

Paleoecological changes during the development of Lake Izyubrinye Solontsi from the Solontsovskie (Shanduyskie) Lakes located in the midlands of the Eastern Sikhote-Alin have been reconstructed. Lake formation is related to landslides on the paleovolcano slopes. A complex study of the peat-bog section (botanical, diatom, spore-pollen, and radiocarbon analysis) allows reconstructing paleoenvironmental changes with high resolution. A considerable variability of lake and swamp environments highly responsive to climate changes in the late Holocene has been revealed. Peat accumulation began about 4000¹⁴С BP. The main peat-forming plants were Sphagnum mosses and herbs, except for the period 2330?1530 ¹⁴C BP (2360?1480 cal. BP), when a swamp overgrown by larch forests and predominantly woody peat accumulated. Forest ecosystems on the lake coasts were quite stable. The role of fir and broadleaved species increased in the composition of dark coniferous forests with Korean pine during the warm phases and the role of birch, in the cold phases; secondary forests occupied the low slopes during the last 1000 years. The age of paleofires has been determined.     

Comparative analysis of the level of gene transcription in two types of HIV-associated lymphoma

In order to characterize the molecular mechanisms of lymphoma formation in HIV-infected humans, a method of two-staged substractive cloning was used, which adequately detects genes whose expression is increased in cells of one lymphoma in comparison with another. Using this method, we determined the spectrum of genes whose expression was increased in centroblastic non-Hodgkin's lymphoma in comparison with immunoblastic non-Hodgkin's lymphoma. Several gene groups were distinguished in this spectrum; their probable involvement in lymphogenesis is discussed.