The Response of Sugarcane (Saccharum officinarum) Cultured Cells to Anoxia and the Selection of a Tolerant Cell Line

The effect of anoxia on the sugarcane (Saccharum officinarum L.) cultured cells was studied in order to elaborate a technique for in vitro selection of cell lines, which would be tolerant to anaerobic stress. Inhibitory and lethal doses of anaerobic incubation were established from the state of the mitochondrial ultrastructure during the anaerobic incubation of cells either with or without exogenous glucose, as well as from the pattern of the post-anaerobic callus growth. An intact state of the mitochondrial ultrastructure and the viability of some cells in the presence of 3% glucose were shown to be maintained for at least 14 days of anaerobic incubation, while the index of post-anaerobic growth decreased by almost 50% even after 72-hour-long anaerobiosis. In the absence of exogenous glucose, a marked destruction of mitochondria and a twofold decrease in the callus growth index were observed as early as after six-hour-long anaerobic stress. A 48-hour-long incubation under these conditions resulted in the maintenance of the intact ultrastructure only in 7–10% of cells, while a 96-hour-long anaerobiosis brought about the complete degradation of the subcellular structure and cell death. A 48-hour-long anaerobiosis without exogenous glucose was chosen for selecting the anoxia-tolerant cell lines. After three cycles of selection, the anoxia tolerance of the selected cell line exceeded the respective index of the initial callus several-fold. In selected line, about 50% of cells retained viability and could resume growth even after 96-hour-long anaerobic incubation. The experimental results obtained were used to determine the possible causes of the heterogeneity of callus cells as regards their anoxia resistance.     

Divalent cation chelators citrate and EDTA unmask an intrinsic uncoupling pathway in isolated mitochondria

We demonstrate a suppression of ROS production and uncoupling of mitochondria by exogenous citrate in Mg²⁺ free medium. Exogenous citrate suppressed H₂O₂ emission and depolarized mitochondria. The depolarization was paralleled by the stimulation of respiration of mitochondria. The uncoupling action of citrate was independent of the presence of sodium, potassium, or chlorine ions, and it was not mediated by the changes in permeability of the inner mitochondrial membrane to solutes. The citrate transporter was not involved in the citrate effect. Inhibitory analysis data indicated that several well described mitochondria carriers and channels (ATPase, IMAC, ADP/ATP translocase, mPTP, mKATP) were not involved in citrate’s effect. Exogenous MgCl₂ strongly inhibited citrate-induced depolarization. The uncoupling effect of citrate was demonstrated in rat brain, mouse brain, mouse liver, and human melanoma cells mitochondria. We interpreted the data as an evidence to the existence of a hitherto undescribed putative inner mitochondrial membrane channel that is regulated by extramitochondrial Mg²⁺ or other divalent cations.     

The interaction between algal viruses and the mussel <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> Lamarck, 1819 (Bivalvia: Mytilidae) in experiments

The utilization (possible assimilation and concentration in organs) of 99% of algal viruses from the water by the Black Sea mussel Mytilus galloprovincialis was confirmed experimentally. This index depends on the duration of the experiment, the complexity of the morphology of the virus, the age (size) of the mussels, and the presence of a nonindicatory microalga, which allows the experimental conditions to be close to natural and is conducive to the agglutination of viruses in pseudofeces and their enhanced utilization by mussels. It was found that some algal viruses concentrated by filter-feeding mussels return to the environment in the feces and are transported to the bottom (where they can be used by benthivores) or diffuse back into the pelagic zone. The results indicate that mussels have a role in the circulation of marine viruses, utilizing and transferring them from the pelagic to the benthic biotope.     

Interhemispheric Differences in Indices of α Activity Spectral Power Electroencephalogram during Bicycle Ergometry

An EEG study during bicycle ergometry in the prone position with the load growing stepwise to submaximal heart rate was carried out in 30 volunteers in order to investigate the spectrum parameters and interhemispheric differences in α activity on the encephalogram. Comparative analysis of EEG data showed a statistically significant increase in α power indices in both hemispheres at the final stage of aerobic exercise and in the course of recovery period with the highest power values recorded in the left hemisphere. Analysis of interhemispheric differences demonstrated right-hemisphere activation during the entire period of the research.     

Peculiarities of the Mechanism of Interactions of Catalytic Antibodies with Organophosphorus Substrates

Catalytic antibodies are a promising model for creating highly specific biocatalysts with predetermined activity. However, in order to realize the directed change or improve their properties, it is necessary to understand the basics of catalysis and the specificity of interactions with substrates. In the present work, a structural and functional study of the Fab fragment of antibody A5 and a comparative analysis of its properties with antibody A17 have been carried out. These antibodies were previously selected for their ability to interact with organophosphorus compounds via covalent catalysis. It has been established that antibody A5 has exceptional specificity for phosphonate X with bimolecular reaction rate constants of 510 ± 20 and 390 ± 20 min^–1M^–1 for kappa and lambda variants, respectively. 3D-Modeling of antibody A5 structure made it possible to establish that the reaction residue L-Y33 is located on the surface of the active site, in contrast to the A17 antibody, in which the reaction residue L-Y37 is located at the bottom of a deep hydrophobic pocket. To investigate a detailed mechanism of the reaction, A5 antibody mutants with replacements L-R51W and H-F100W were created, which made it possible to perform stopped-flow kinetics. Tryptophan mutants were obtained as Fab fragments in the expression system of the methylotrophic yeast species Pichia pastoris. It has been established that the effectiveness of their interaction with phosphonate X is comparable to the wild-type antibody. Using the data of the stopped-flow kinetics method, significant conformational changes were established in the phosphonate modification process. The reaction was found to proceed using the induced-fit mechanism; the kinetic parameters of the elementary stages of the process have been calculated. The results present the prospects for the further improvement of antibody-based biocatalysts.     

Molecular mechanisms of cardiomyogenesis and perspectives of cardiomyocyte regeneration in cardiac failure

This review analyzes the current state in investigations of molecular, genetic and cellular mechanisms of cardiac development as well as perspectives to use this knowledge for treatment of cardiac failure by means of replenishing cardiomyocytes in damaged myocardium.     

Electron microscopic study of Burkholderia cepacia biofilms

Using the methods of transmission electron microscopy, the structure of the biofilms formed by the bacterium Burkholderia cepacia (clinical isolate and mutants with an increased and decreased ability to produce biofilms) were investigated. The biofilms were obtained on a liquid nutrient medium or on an abiotic surface (polystyrene). It has been demonstrated that the cultures of the studied strains differ in some morphological and functional characteristics. In biofilms, changes in the size and submicroscopic organization of all the components of bacterial cells occur. Staining biofilms with ruthenium red revealed the presence of exopolysaccharides in the intercellular space. The differences in the ultrastructure of bacterial films formed on nutrient medium and abiotic surfaces were demonstrated.     

Structural and Functional Investigation of White Sea Water and Bottom Sediments

Statistical analysis of dynamic indices of biopolymers enzymatic destruction in unstratified and stratified White Sea water has revealed specific properties of protease and amylase activities. We analyzed the component composition and hydrolytic enzymatic activities in the surface layer of the bottom sediments (0–2 cm). The relationship between protease and amylase enzymatic activities in the surface sediments with different content of pelite fraction is discussed.     

Investigation on the mechanisms of leukocyte alteration in patients with intolerance to some drugs (with novocaine as a model)

The mechanisms of novocain damaging action on blood cells in persons with increased sensitivity to this drug were studied in the leukocyte alteration test. The leading role of histamine liberated from basophils was established. The increased sensitivity to novocain was shown not to be passively transferred to the cells of healthy donors with patient serum with intolerance to the drug; moreover, the joint action of both cell-mediated and thermolabile humoral factors was found to be necessary for the realization of leukocyte alteration under the action of novocain. The comparison of the information content of a number of methods--skin testing, dosed provocation, leukocyte alteration test and chemiluminescence--for revealing increased sensitivity to novocain in 30 persons with adverse reactions to this preparation registered in their medical history. The two in vitro tests were shown to be comparable in their diagnostic significance with the method of dosed provocation.