Amino acid sequences of two immune-dominant epitopes of recoverin are involved in Ca<Superscript>2+</Superscript>/recoverin-dependent inhibition of phosphorylation of rhodopsin

Antibodies AB^60–72 and AB^80–92 against two immune-dominant epitopes of photoreceptor Ca²⁺-binding protein recoverin, 60-DPKAYAQHVFRSF-72 and 80-LDFKEYVIALHMT-92, which can be exposed in a Ca²⁺-dependent manner, were obtained. The presence of AB^60–72 or AB^80–92 results in a slight increase in Ca²⁺-affinity of recoverin and does not affect significantly a Ca²⁺-myristoyl switch mechanism of the protein. However in the presence of AB^60–72 or AB^80–92 recoverin loses its ability to interact with rhodopsin kinase and consequently to perform a function of Ca²⁺-sensitive inhibitor of rhodopsin phosphorylation in photoreceptor cells.     

Role of protein kinases of human red cell membrane in deformability and aggregation changes

The proteomic analysis has showed that red cell membrane contains several kinases and phosphatases. Therefore the aim of this study was to investigate the role of protein kinases of human red cell membrane in deformability and aggregation changes. Exposure of red blood cells (RBCs) to some chemical compounds led to change in the RBC microrheological properties. When forskolin (10 microM), an adenylyl cyclase (AC) and a protein kinase A (PKA) stimulator was added to RBC suspension, the RBC deformability (RBCD) was increased by 20% (p < 0.05). Somewhat more significant deformability rise appeared after RBC incubation with dB-AMP (by 26%; p < 0.01). Red cell aggregation (RBCA) was significantly decreased under these conditions (p < 0.01). Markedly less changes of deformability was found after RBC incubation with protein kinase stimulator C (PKC)--phorbol 12-myristate 13-acetate (PMA). This drug reduced red cell aggregation only slightly. It was inhibited red cell tyrosine phosphotase activity by N-vanadat and was obtained a significant RBCD rise and RBCA lowering. The similar effect was found when cells were incubated with cisplatin as a tyrosine protein kinase (TPK) activator. It is important to note that a selective TPK inhibitor--lavendustin eliminated the above mention effects. On the whole the total data clearly show that the red cell aggregation and deformation changes were connected with an activation of the different intracellular signaling pathways.     

Genetics of human populations of Caucasus: distribution of various immunological and biochemical markers in eastern Georgia

The distribution of genetic markers of blood groups (AB0, P, Rhesus, MNSs, Duffy, Lewis, Kell-Cellano), of the serum proteins (Hp, Gc, Tf, C'3), red-cell enzymes (AcP, EstD, GLO1) and also ABH-secretion among seven native populations of Eastern Georgia has been studied. The frequencies of genes and haplotypes were calculated for the polymorphic markers and the results obtained were used in analysis of interpopulation variation and genetic relationship of these populations to their geographical neighbours as well as to European and West Asian populations.     

The estimation of microcirculation state in cerebrovascular disorders by data of laser Doppler flowmetry and hemorheological parameters

The study was aimed to evaluate microvascular blood flow and theological blood properties in healthy volunteers (n = 27) and patients with cerebral accident (n = 30). To study cutaneous blood flow we used the multifunctional laser analyzer of blood microcirculation LAKK (LAZMA, Moscow) with spectrophotometric channel and wavelet analysis of blood flow oscillations. Viscosity of the whole blood, plasma, RBC aggregability and deformability were assessed. Results: microcirculation index was by 25% (p < 0.05) lower in patients compared to the control group. Computing amplitude-frequency range of blood flow oscillations revealed notable changes in the blood flow regulation mechanisms under cerebrovascular accident: the amplitudes of all active rhythms (endothelial, neurogenic and myogenic ones) were increased. In spite of such activization of regulatory mechanisms, aimed to keep essential blood supply to tissue, index of specific oxygen consumption by tissue was decreased by 21% (p < 0.05) under cerebrovascular disorders. Blood rheological properties in patients group were impaired compared to the healthy group: blood viscosity was increased because of elevated plasma viscosity, increased RBS aggreagation and decreased erythrocyte deformability. Thus, our results demonstrated the decrease of tissue perfusion, activization of vasodilating mechanisms, impaired blood rheology and the decrease of oxygen supply to tissue in patients with cerebrovascular accident. Statistical analysis revealed a number of significant correlations between the hemorheological parameters and passive rhythms of microcirculation in norm. In patients blood viscosity correlated to the amplitude of active regulatory rhythms (endothelial, neurogenic and myogenic oscillations). Close interralations between rheological and microcirculation parameters testified the important role of hemorheological factors in maintenance of microvascular blood flow and oxygen delivery to tissue.     

Anti-ischemic protection of the brain using water-soluble form of aspirin-acelisin]

The domestic water-soluble aspirin (acelisin) has been used as an anti-ischemic brain protector. The total brain ischemia has been implemented in accordance with an original technique for 17 to 35 min. The doses of acelisin from 25 to 250 mg/kg have been tested during experiments. The infusion of solutions has been carried out before ischemia, 15 min before reperfusion and just after the beginning of reperfusion. The functional status and survival of rats have been evaluated during a week. The best result has been reached with 150 mg/kg acelisin injected 30 min before ischaemia. A positive effect was reported when acelisin was used in early postischaemic period.     

Isolation and Analysis of Extractives from White Cinquefoil (<Emphasis Type="Italic">Potentilla alba</Emphasis> L.) Grown under Different Conditions

Potentilla alba L. is used as a medicinal plant that contains a variety of biologically active substances. Natural resources are not meeting the needs of the pharmaceutical industry. We obtained the first biomass of P. alba plant-regenerants using hydroponics technique with clonal micropropagation. We have conducted a comprehensive study of the chemical composition of a vegetable raw materials P. alba, obtained in the Biotechnology Department (plant-regenerants) in comparison with raw material obtained from plants grown under field conditions (intact plants). We have established the quantitative content of the structural components in the samples: cellulose in roots and rhizomes of intact plants, 15.4%, in the roots of plant-regenerants, 4.3%, in the leaves of plant-regenerants, 2.5%; lignin in roots and rhizomes of intact plants, 40.7%, in the roots of plant-regenerants, 37.0%, and in the leaves of plant-regenerants, 36.8%. We determined the content of extractives in P. alba samples, recovered by sequential treatment with hexane, 96% and 40% ethanol solution, water and 1% aqueous sodium hydroxide solution. We identified the total content of extractives in the roots and rhizomes of intact plants at 15.3%, in the roots of plants-regenerants, 11.2%, and in the leaves of plant-regenerants, 5.1%. We characterized the chemical composition of extractives by UV-spectroscopy. Phenolic substances (λ = 279.5–280.0 nm) were dominant in the composition of the extracts. We have established the authenticity of the samples by the TLC chromatography based on the presence of flavonoids and tannins. We showed the identity of the phytochemical composition of vegetable raw materials produced by micropropagation and grown hydroponically for two months.     

Taphonomy and compositional fidelity of Quaternary fossil assemblages of terrestrial gastropods from carbonate-rich environments of the Canary Islands

Quaternary aeolian deposits of the Canary Islands contain well‐preserved terrestrial gastropods, providing a suitable setting for assessing the taphonomy and compositional fidelity of their fossil record over ~13 kyr. Nine beds (12, 513 shells) have been analysed in terms of multivariate taphonomic and palaeoecological variables, taxonomic composition, and the stratigraphic and palaeontological context. Shells are affected by carbonate coatings, colour loss and fragmentation. Shell preservation is size‐specific: juveniles are less fragmented and show colour preservation more commonly than adults. In palaeosols, the adult shell density correlates negatively with the proportion of fragmented adults, negatively with the proportion of juveniles, and positively with the proportion of adults with coatings. High bioturbation intensity in palaeosols is associated with low shell fragmentation and high proportion of shells with coatings. These relationships imply that high adult density in palaeosols was driven by an increase in shell production rate (related to a decrease in predation rates on adults and a decrease in juvenile mortality) and a decrease in shell destruction rate (related to an increase in durability enhanced by carbonate precipitation). In dunes, the relationships between taphonomic alteration, shell density and bioturbation are insignificant. However, dune assemblages are characterized by a lower frequency of shells with coatings and higher rates of colour loss, indicating lower shell durability in dunes than in palaeosols. Additionally, non‐random differences in the coating proportion among palaeosols imply substantial temporal variation in the rate of carbonate crust formation, reflecting long‐term changes in bioturbation intensity that covaries positively with shell preservation. Dunes and palaeosols do not differ in species abundances despite differences in the degree of shell alteration, suggesting that both weakly and strongly altered assemblages offer data with a high compositional fidelity. Carbonate‐rich terrestrial deposits originating in arid conditions can enhance the preservation of gastropods and result in fossil assemblages that are suitable for palaeoecological and palaeoenvironmental studies of terrestrial ecosystems.     

Applications of nanoparticles in biology and medicine

Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. Their unique size-dependent properties make these materials superior and indispensable in many areas of human activity. This brief review tries to summarise the most recent developments in the field of applied nanomaterials, in particular their application in biology and medicine, and discusses their commercialisation prospects.     

Search for Functionally Significant Motifs and Amino Acid Residues of Actin

The scientific interest to the structural and functional properties of actin is determined by its abundance in cells. Being an important component of the cytoskeleton, actin is involved in many protein-protein interactions. Using crystal structures and molecular models, we have mapped the amino acid residues that are involved in these interactions and form the ATP-binding site of the actin monomer. Moreover, using mass spectrometry and high-performance liquid chromatography methods, we have discovered the regions of the amino acid sequence of actin that form the core of the actin fibril. According to the bioinformatic analysis, these regions are amyloidogenic and are located in the C-terminal region and in the hinge between the first and third subdomains. The data obtained are applicable to chordate actin, because multiple alignment revealed highly conserved amino acid sequences. In turn, the comparison of the chordate actin with the bacterial homologs showed the presence of numerous amino acid substitutions and insertions.