Influence of the Hall effect on the plasma dynamics in an MTF/MAGO chamber

The role of the Hall effect in experiments on the magnetic implosion of a D-T plasma in a cylindrical MTF/MAGO chamber fed from a helical explosive magnetic generator is investigated. The plasma dynamics is simulated numerically by a 2D code developed for solving the set of MHD equations with account of the Hall effect. In simulations, the generator, the break switch, and other units were replaced with LR circuits. It is shown that taking into account the Hall effect provides better agreement between numerical simulations and experimental data.     

On the importance of dimensionality of space in models of space-mediated population persistence

Spatially explicit models have become widely used in today's mathematical ecology to study persistence of populations. For the sake of simplicity, population dynamics is often analyzed with 1-D models. An important question is: how adequate is such 1-D simplification of 2-D (or 3-D) dynamics for predicting species persistence. Here we show that dimensionality of the environment can play a critical role in the persistence of predator-prey interactions. We consider 1-D and 2-D dynamics of a predator-prey model with the prey growth damped by the Allee effect. We show that adding a second space coordinate into the 1-D model results in a pronounced increase of size of the domain in the parametric space where predator-prey coexistence becomes possible. This result is due to the possibility of formation of a number of 2-D patterns, which is impossible in the 1-D model. The 1-D and the 2-D models exhibit different qualitative responses to variations of system parameters. We show that in ecosystems having a narrow width (e.g. mountain valleys, vegetation patterns along canals in dry areas, etc.), extinction of species is more probable compared to ecosystems having a pronounced second dimension. In particular, the width of a long narrow natural reserve should be large enough to guarantee nonextinction of species via interaction of 2-D population patches.     

Acute and remote biochemical and physiological effects of exhaustive weightlifting exercise

The goal of the work was a study of exhaustive weightlifting exercise effect on prolonged changes in physiological and biochemical variables characterized functional status of skeletal muscles. An exercise gave rise to significant blood lactate concentration increase that was indicative of an anaerobic metabolism to be a predominant mechanism of muscle contraction energy supply. A reduction of m. rectus femoris EMG activity (amplitude and frequency), tonus of tension and an increase in tonus of relaxation were found immediately after exercise. Both EMG amplitude and frequency were increased 1 day post-exercise. However, after 3 days of recovery, EMG amplitude and frequency were decreased again and, in parallel, blood serum creatine kinase (CK) activity was significantly increased. After 9 recovery days, all measured variables with the exception of CK were normalized. A significant reverse correlation was found between blood serum lactate concentration and m. rectus femoris EMG activity at the same time points. Blood serum CK activity and m. rectus femoris EMG and tonus variables were observed to be significantly reversely correlated on the 3rd post-exercise day. Presented data demonstrate that exhaustive exercise-induced muscle injury resulted in phase alterations in electrical activity and tonus which correlated with lactate concentration and CK activity in blood serum.     

Proteomic and electron microscopy study of myogenic differentiation of alveolar mucosa multipotent mesenchymal stromal cells in three-dimensional culture

Myocyte differentiation is featured by adaptation processes, including mitochondria repopulation and cytoskeleton re-organization. The difference between monolayer and spheroid cultured cells at the proteomic level is uncertain. We cultivated alveolar mucosa multipotent mesenchymal stromal cells in spheroids in a myogenic way for the proper conditioning of ECM architecture and cell morphology, which induced spontaneous myogenic differentiation of cells within spheroids. Electron microscopy analysis was used for the morphometry of mitochondria biogenesis, and proteomic was used complementary to unveil events underlying differences between two-dimensional/three-dimensional myoblasts differentiation. The prevalence of elongated mitochondria with an average area of 0.097 μm² was attributed to monolayer cells 7 days after the passage. The population of small mitochondria with a round shape and area of 0.049 μm² (p < 0.05) was observed in spheroid cells cultured under three-dimensional conditions. Cells in spheroids were quantitatively enriched in proteins of mitochondria biogenesis (DNM1L, IDH2, SSBP1), respiratory chain (ACO2, ATP5I, COX5A), extracellular proteins (COL12A1, COL6A1, COL6A2), and cytoskeleton (MYL6, MYL12B, MYH10). Most of the Rab-related transducers were inhibited in spheroid culture. The proteomic assay demonstrated delicate mechanisms of mitochondria autophagy and repopulation, cytoskeleton assembling, and biogenesis. Differences in the ultrastructure of mitochondria indicate active biogenesis under three-dimensional conditions.     

Universal method for single nucleotide substitution identification

A new approach to the identification of point mutations by allele-specific PCR was proposed. The mutation R408W of the human phenylalanine hydroxylase gene was used as a model. A high specificity of the approach was achieved by the use of primers partially complementary to the genomic DNA. Polyethylene glycol covalently attached to one of the allele-specific primers provides for the differential identification of the PCR products due to a change in electrophoretic mobility.     

The influence of cyclic heating and cooling on Escherichia coli survival

Repeated heating and cooling in lethal (2-52 degrees C) and nonlethal (2-37 degrees C) temperature ranges resulted in cell death of Escherichia coli B/r and E. coli B(S-1) suspended in 0.01 M phosphate buffer, pH 7.0 at varying osmotic pressure, but not in cow's milk. The lethal effect increased with the rate of heating and with increasing suspension media tonicity; it may be caused by the temperature destabilization of cellular osmotic homeostasis.     

Rap1 couples cAMP signaling to a distinct pool of p42/44MAPK regulating excitability,synaptic plasticity,learning, and memory

Learning-induced synaptic plasticity commonly involves the interaction between cAMP and p42/44MAPK. To investigate the role of Rap1 as a potential signaling molecule coupling cAMP and p42/44MAPK, we expressed an interfering Rap1 mutant (iRap1) in the mouse forebrain. This expression selectively decreased basal phosphorylation of a membrane-associated pool of p42/44MAPK, impaired cAMP-dependent LTP in the hippocampal Schaffer collateral pathway induced by either forskolin or theta frequency stimulation, decreased complex spike firing, and reduced the p42/44MAPK-mediated phosphorylation of the A-type potassium channel Kv4.2. These changes correlated with impaired spatial memory and context discrimination. These results indicate that Rap1 couples cAMP signaling to a selective membrane-associated pool of p42/44MAPK to control excitability of pyramidal cells, the early and late phases of LTP, and the storage of spatial memory.     

Spectrum and methods of detection of mutations in a phenylalanine hydroxylase gene from patients with phenylketonuria from the Novosibirsk region]

Phenylketonuria (PKU) is a widespread autosome recessive hereditary disease caused by a deficiency of the liver enzyme phenylalanine hydroxylase, which results in the distortion of phenylalanine metabolism and accumulation of toxic metabolites. The knowledge of molecular bases of PKU is of a high social importance as it enables phenotypic correction of the disease in the case of its early diagnostics. This disease is known to be associated with mutations in the phenylalanine hydroxylase gene, the distribution and mutation spectrum having pronounced ethnic and regional features. We studied the spectrum of mutations in the phenylalanine hydroxylase gene in a group of patients with PKU from the Novosibirsk region to reveal 10 missense point mutations, 1 mutation in the splice donor site, and 1 microdeletion. For these mutations, most widely distributed in the region, we used straightforward detection methods based on the restriction fragment length polymorphism (RFLP), artificial constructed restriction sites (ACRS) PCR, and denaturing gradient gel electrophoresis (DGGE).