Sepcific fragmentation of DNA heteroduplex molecules of two bacteriophage lambda mutants with endonuclease Si from Aspergillus oryzae.

Heteroduplex DNA molecules of two bacteriophage mutants (lambda b2 and lambda i434ct68) were obtained by the method of molecular hybridization. These heteroduplexes possessed two types of loops formed as a result of: a) deletion in one of the DNA strands; and b) substitution of a DNA fragment for nonhomological one. The digestion of heteroduplexes with single-stranded specific nuclease SI from Aspergillus oryzae produced two fragments at 37 degrees C and three ones at 55 degrees C. The separation of fragments and determination of their molecular weight were carried out by means of electrophoresis in agarose. The molecular weights both measured and preliminarily calculated proved to be close. One of the fragments was identificated by its biological activity in CaCl2-dependent infectious system with helperphage.     

Ultrastructure of the sensory formations of the internal ear in the common frog

By means of scanning electron microscopy method, sensory formations of the membranous labyrinth has been studied in the frog (Rana temporaria). The form of sensory fields and morphological peculiarities of the hair cells are described. For the saccular macula, amphibian and basilar papillae, the number of the hair cells is calculated, orientation of the hair cell poles is demonstrated.     

Properties of pig liver transketolase]

Some properties of homogeneous transketolase from pig liver were studied. It was shown that the pH optimum of the transketolase reaction lies within the range of 7.8--8.2. The isoelectric point is at pH 7.6--7.8. The molecular weight of transketolase is 138,000 +/- 3,000 as determined by the sedimentation equilibrium method and about 152,000 according to the data from gel filtration through Sephadex G-200. The enzyme molecule is a tetramer of the alpha 2 beta 2 type. The molecular weights of the alpha- and beta- subunits determined by polyacrylamide gel in the presence of sodium dodecyl sulfate are 52,000--56,000 and 27,000--29,000, respectively. Transketolase contains about two moles of TPP per mole of protein and does not require metal ions for its catalytic activity.     

Cytomorphological and cultural characteristics of tylosin-producing strains with different antibiotic activity]

Cytomorphological and cultural characteristics of highly and low active collection strains of Streptomyces fradiae producing tylosin were studied. The strains were grown on agarized and liquid media. It was shown that unlike the low active strain, the highly active one was less sporogenic, the difference being more pronounced when tylosin was added to the agarized medium. When the strains were grown in the fermentation medium there were detected differences between them in the growth type and microcolony structure at the early stages of the fermentation process. During intensive synthesis of tylosin spheric structures were found to form near the hyphal surfaces. The phenomenon was previously observed in cultures producing other antibiotics. In the low active strain the structures were single while in the highly active strain they formed in large numbers.     

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.     

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.     

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.     

The role of laboratory-scale bioreactors at the semi-continuous and continuous microbiological and biotechnological processes

Applied Microbiology and Biotechnology - Laboratory-scale bioreactors represent an important part of microbiological, biotechnological, and biochemical researches. The small volume bioreactors...     

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.