Capillary isotachophoresis study of lipoprotein network sensitive to apolipoprotein E phenotype. 1. ApoE distribution between lipoproteins

Sixteen patients differing widely in plasma triglyceride content were divided into three groups by their apolipoprotein E (apoE) phenotype—E33 homozygotes, E23, and E34 heterozygotes. The plasma lipid and apoE distribution between individual lipoproteins was followed by capillary isotachophoresis (CITP) of plasma samples pre-stained with lipid fluorescent probe NBD-C6-ceramide and by fluorescein-labeled apoE, respectively. Among 12 peaks visualized by ceramide staining, an individual peak with very low density lipoproteins (VLDL) was identified. The VLDL cholesterol and apoE content determined by CITP directly in whole plasma were significantly related to their content as determined by conventional analysis with isolated VLDL. The ceramide distribution among lipoprotein pools was insensitive to apoE phenotype (49–53 : 7–11 : 39–43% for HDL, VLDL, and IDL/LDL, respectively) while the preferential binding of apoE to VLDL was observed in E34 patients compared to E33 (62 : 19 : 20 vs. 70 : 9 : 22%). In a study of apoE/F displacement from lipoproteins at plasma titration by apoC-III in vitro, apoE was found to bind more tightly to VLDL from E34 compared to E33 patients as evidenced by both the increased non-displaceable apoE pool, the increased VLDL sorbtion capacity for apoE, and the decreased displacement parameter in a “container” model of lipoprotein binding. Two different types of apoE package in a whole lipoprotein profile were observed. ApoE structure in a particular lipoprotein may underlie the phenotype-sensitive apoE distribution and apoC-III interference in hypertriglyceridemia.     

The effect of synthetic antioxidants,anphen derivatives,on erythrocyte morphology

The effect of new synthetic antioxidants, anphens, on erythrocyte morphology was studied. Insignificant cell transformations induced by the hydrophilic derivative of anphen-1 into echinocytes, as well as cell transformations into stomatocytes under the action of hydrophobic derivatives of anphens-2, 3, and 4 were revealed. The data we obtained indicate the intercalation of these compounds into the erythrocyte membrane. The distribution of compounds in the intra-membrane space depends on their hydrophobicity. A hydrophilic compound, anphen-1, is predominantly located in the outer monolayer of the membrane, while hydrophobic derivatives occur in the inner monolayer. It is proposed that the biological activities of anphen-3 and anphen-4 can occur in both monolayers as they move through the membrane, while the hydrophilic compound, anphen-1, exerts an insignificant membranotropic effect and can act only in the outer monolayer of the membrane. Variability in the efficiency of the concentration-dependent modifying action of the compounds with different hydrophobic properties has been found.     

Molecular motility of a fluorescent probe in binding sites of albumin molecules

The molecular mobility of the fluorescent probe, N-(carboxymethyl)imide of 4-(dimethylamino)naphthalic acid (K-35) in three types of binding sites on a human serum albumin (HSA) molecule has been studied. The time-resolved decay of K-35 polarized fluorescence in HSA has been studied and it has been shown that probe molecules bound to different sites have different fluorescence decay time, which poses problems in the interpretation of polarization decay. However, it has been found that, in the case of rather slow thermal rotation of the probe, the decay of each of vertical and horizontal polarized fluorescence components can be approximated by three exponentials corresponding to three types of binding sites. The mobility of the probe in different sites was estimated. The mobility was different but hindered by tens of times in all sites as compared with the rotation of K-35 in water. The slowest motion occurred in the sites of the first type localized in the region of the well known first drug-binding site: here the rotational correlation was close to 72 ns or more. In the sites of the second type, the time was about 40 ns, and in the sites of the third type, the time was about 10 ns. It was found that the higher the rotation rate, the higher the fluorescence quenching rate. Probably, it is this motion that is responsible for different fluorescence decay times in different HSA sites.     

Effect of chemical chaperones on properties of lysozyme and the reaction center protein from Rhodobacter sphaeroides

The influence of three chemical chaperones: glycerol, 4-hexylresorcinol, and 5-methylresorcinol on the structure, equilibrium fluctuations, and the functional activity of the hydrophilic enzyme lysozyme and the transmembrane reaction center (RC) protein from Rb. sphaeroides in a broad range of concentrations has been studied. Selected chemical chaperones are strongly different by the structure and action on hydrophilic and membrane proteins. The influence of the chemical chaperones (except methylresorcinol) on the structure, dynamics, and functional properties of lysozyme and RC protein are well described within the frames of extended models of preferential hydration and preferential interaction of protein with a chemical chaperone. A molecule of hexylresorcinol consists of a hydrophobic (alkyl radical) and a hydrophilic (aromatic nuclus) moieties. This fact provides additional regulation of functional activity of lysozyme and RC by hexylresorcinol. The influence of methylresorcinol on proteins differs from that of glycerol and hexylresorcinol. Methylresorcinol interacts with the surface of lysozyme directly, not via water hydrogen bonds. This leads to a decrease in denaturation temperature T(d), and an increase in the amplitude of equilibrium fluctuation, which allows him to be a powerful activator. Methylresorcinol interacts with the membrane RC protein only by the condensation of hydration water, which is negligible in the case of methylresorcinol. Therefore, methylresorcinol does not effect the functional properties of the RC protein. It was concluded that various chaperones at one and the same concentration and chaperones at different concentrations form diverse 3D structures of proteins, which differ by dynamic and functional characteristics.     

The impact of the high dose-refuge strategy on the Bt-crop yield. Mathematical simulations

A mathematical model is presented, which describes interactions between Bt-plants and pests in terms of the plant growth rate, plant annual reseeding, consumption of plant biomass by pests, the action of Bt toxins, and the emergence of Bt-resistant insects. It has been shown that the migration of Bt-susceptible insects affects the Bt-crop yield dynamics and provides the exclusion of Bt-resistant pests if the migration exceeds the threshold value.     

Kinetic chemiluminescence as a method for the study of free radical reactions

The review gives concepts of analysis of kinetics of complex reactions with the participation of free-radicals. The concepts are based on the comparison of the kinetic curves of the chemiluminescent reactions in the presence of a physical enhancer coumarin C-525 with the simulated kinetic functions. This method was applied to the investigation of the mechanism of a branched-chain reaction of lipid peroxidation in biological and phospholipid membranes as well as to the effect of antioxidants and determination of their activities. It was also used for studying the reaction of the formation of free radicals in the complex of cytochrome c with cardiolipin. This reaction plays a key role in the initiation of apoptosis.     

Noninvasive estimation of the oxygen state of experimental tumor by diffuse optical spectroscopy

The potentialities of diffuse optical spectroscopy for the noninvasive estimation of the oxygen state of experimental tumors have been demonstrated. The distribution of total, oxygenated and deoxygenated hemoglobin, as well as the level oxygen saturation of blood have been shown using two tumor models differing in the histological structure and functional characteristics. The results obtained by the optical method have been verified by immunohistochemical examination of tissue specimens with the exogenous hypoxia marker pimonidazole.     

Assessment of soil degradation in areas of nuclear explosions at the Semipalatinsk nuclear test site

The degree of the soil cover degradation at the Balapan and Experimental Field test sites was assessed on the basis of the Allium-test of soil toxicity and international guidelines on the radioactive restriction of solid materials (IAEA, 2004) and the environment (Smith, 2005). Large scale soil-cover degradation maps (1: 25000) were made. The main part of the mapped area contains highly contaminated toxic degraded soil. It was found that the relationship between soil toxicity and total radionuclide activity concentration is described by power functions. When the calculated value (413–415 Bq/kg of air-dried soil) increases, the soil becomes toxic to plants. This value is 7.8 times higher than the maximum value for background territories (53 Bq/kg) surrounding the SNTS. The Russian sanitary and hygienic guidelines (Radiation safety standards, 2009; Sanitary regulations of radioactive waste management, 2003) underestimate the degree of soil radioactive contamination for plants.     

miR-126 inhibits proliferation of small cell lung cancer cells by targeting SLC7A5

Despite intensive efforts to improve therapies, small cell lung cancer (SCLC) still has a dismal median survival of 18 months. Since miR-126 is under-expressed in the majority of SCLC tumors, we investigated the effect of miR-126 overexpression on the proliferation and cell cycle distribution of H69 cells. Our results demonstrate that miR-126 inhibits proliferation of H69 cells, by delaying the cells in the G1 phase. Short interfering RNA (siRNA) mediated suppression of SLC7A5, a predicted target of mir-126, has the same effect on H69 cells. We also show for the first time that SLC7A5 is a direct target of miR-126.     

Comparative cytogenetic analysis of hexaploid Avena L. species

Using C-banding method and in situ hybridization with the 45S and 5S rRNA gene probes, six hexaploid species of the genus Avena L. with the ACD genome constitution were studied to reveal evolutionary karyotypic changes. Similarity in the C-banding patterns of chromosomal and in the patterns of distribution of the rRNA gene families suggests a common origin of all hexaploid species. Avena fatua is characterized by the broadest intraspecific variation of the karyotype; this species displays chromosomal variants typical of other hexaploid species of Avena. For instance, a translocation with the involvement of chromosome 5C marking A. occidentalis was discovered in many A. fatua accessions, whereas in other representatives of this species this chromosome is highly similar to the chromosome of A. sterilis. Only A. fatua and A. sativa show slight changes in the morphology and in the C-banding pattern of chromosome 2C. These results can be explained either by a hybrid origin of A. fatua or by the fact that this species is an intermediate evolutionary form of hexaploid oats. The 7C-17 translocation was identified in all studied accessions of wild and weedy species (A. sterilis, A. fatua, A. ludoviciana, and A. occidentalis) and in most A. sativa cultivars, but it was absent in A. byzantina and in two accessions of A. sativa. The origin and evolution of the Avena hexaploid species are discussed in context of the results.