Showing papers in "Ukraïns'kyĭ biokhimichnyĭ zhurnal in 2008"

Vibrational spectra of the steroid hormones, estradiol and estriol, calculated by density functional theory. The role of low-frequency vibrations.

Abstract: The structure of estrogen receptors and their interaction with 17β-estradiol and estriol are of particular interest today because the treatment of breast cancer and the cause of the disease are intricately linked to the activity of the estrogen receptor and the normal blood serum level of these hormones Molecular geometry and vibration frequencies of these steroid hormones are calculated by density functional theory with the B3LYP/ 6-31G** approximation Intensities of infrared absorption and Raman spectra for estradiol are in an agreement with the experiment data The assignments of all vibrational bands in the spectra of these hormones are presented on the basis of quantum chemical calculations of frequencies and normal modes For the large number of bands such an assignment is made for the first time The analysis of infrared spectra of both hormones indicates some nontrivial structure-spectra correlations A series of specific vibrations is predicted in the low-frequency region of the IR spectra; their role in hormone-receptor interaction and in energy transfer processes are discussed The search of the optimized geometrical structure by minimization of the total energy gradient is accompanied by the second derivatives calculation; diagonalization of the Hessian matrix leads finally to solution of vibration problem The 17β-estradiol molecule consists of 44 atoms and has 126 normal modes of internal vibrations All these normal modes are presented together with their analysis and comparison with experimental data From this comparison we have obtained an assignment of all absorption IR bands of 17β-estradiol recorded earlier in KBr For all stretching vibrations our assignment is in agreement with the previous one, obtained on the basis of the empirical rules Direct DFT calculation of vibrational frequencies cannot provide a 100% agreement with the experimental IR spectra and scaling factors in the range of 095–097 are used in order to fit theoretical and experimental data K e y w o r d s: 17β-estradiol, estriol, density functional theory, B3LYP/6-31G**, IR and Raman spectra of steroid hormone, vibrational frequency

[New amides of phenazine-1-carboxylic acid: antimicrobial activity and structure-activity relationship].

Abstract: Complex investigation of new phenazine-1-carboxylic acid (PCA-1) phenylamides allowed to reveal their ability for substantial growth retardation of three gram-positive bacterial strains--Micrococcus sp., Erysipelothrix rhusiopathiae and Staphylococcus aureus. The strong inhibitory activity of PCA-1 derivatives towards the RNA synthesis in in vitro T7-RNA-polymerase transcription system was also shown, and this property depended on concentration and structure of the tested compounds. The methods of computer modeling outlined the possible mechanism of RNA synthesis inhibition by PCA-1 amides: this process is arisen due to formation of stable complex of substances with enzyme at the position of substrate (rNTP) binding site. The revealed accordance of suppressor PCA-1 amides action in the enzymatic transcription system with antibacterial activity of these agents allows assuming that DNA-dependent RNA polymerase might be one of the cellular targets for tested bacteria. Such an approach permits to propose the use of such in vitro transcription model system to reveal biologically active substances among newly synthesized compounds, having close action mechanism.

Alternative splice variants of rat 6-phosphofructo-2-kinase/ fructose-2,6-bisphosphatase-4 mRNA.

Abstract: Expression of 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase-4 (PFKFB-4) mRNA was studied in different rat organs. Several new unique alternative splice variants of PFKFB-4 mRNA were identified. They have deletions or inserts in fructose-2,6-bisphosphatase region as well as different length and amino acid sequence of C-terminal part. However, 6-phosphofructo-2-kinase catalytic domains were identical in all variants. Moreover, the expression of different alternative splice variants of PFKFB-4 mRNA has shown tissue specificity. Expression of both alternative splice variants of PFKFB-4 mRNA significantly changed in rats treated by methyl tretbutyl ether, ecologically dangerous chemical compound. Results of this investigation indicate a possible role of PFKFB-4 splice isoforms in cell-specific regulation of glycolysis and demonstrate the sensitivity of the regulation of alternative splicing to the action of toxic chemical compounds, in particular methyl tertbutyl ether.

Xanthine oxidase activity in the rat liver tissue in the process of oncogenesis

Abstract: The work is dedicated to the investigation of xanthine oxidase activity in liver homogenate of rats with tumour at different stages of Guerin carcinoma oncogenesis on the preliminary low-dose irradiation background. Special attention is paid to studying enzyme oxidase form activity, the level of its reactive oxygen species generation and content of thiol groups in protein fraction, which possesses xanthine oxidase activity. The period of Guerin carcinoma active growth is characterized by the increase of total xanthine oxidase activity in the liver. It was found that oxidase activity and the level of O2* generation increase in the preliminary irradiated organism in the period of Guerin carcinoma active growth, as a result of enzyme SH-groups oxidation. At the terminal stages of oncogenesis the decrease of xanthine oxidase activity is accompanied by degradation of the molecule protein part.

[Sensor system based on molecular-imprinted polymer membranes for the selective recognition of aflatoxin B1].

Abstract: lymer membranes, synthesized using acrylamide as a functional monomer, were characterized by sufficient mechanical stability and high adsorbtion capability towards aflatoxin B1. The molecularly-imprinted polymer membranes were characterized by the pronounced imprinting effect as well as by insignificant adsorbtion of aflatoxins B2 and G2. Therefore, the synthetic analogues of bioreceptors able to individual recognition of aflatoxin B1 were obtained and used as a basis for the optical sensor system for aflatoxin B1 detection in a concentration range 1-500 ng/ml.

[Hyaluronic acid, receptor CD44, and their role in diabetic complications].

Abstract: Hyaluronic acid (HA) is a straight chain glycosaminoglycan polymer composed of repeating units of the disaccharide [-D-glucuronic acid-beta1,3-N-acetyl-D-glucosamine-beta1,4-]n, and is found in vertebrates and certain microorganisms. The molecular weight of HA chains is usually equal to approximately 1-10 and MDa, n > 10(3-4), although it can exists as oligosaccharides under some physiological and pathological conditions. HA resides on the cell surface or in the extracellular space, but it also occurred inside the mammalian cells. HA is synthesized in mammals by three enzymes with polymers of varying chain length. The biological functions of HA include the maintenance of elastoviscosity of liquid connective tissues, control of tissue hydration, supramolecular assembly of proteoglycans in the extracellular matrix and besides numerous receptor-mediated functions in cell attachment, mitosis, migration, tumor development, wound healing and inflammation. The extensive repertoire of biological functions of HA corresponds to the existence of a large repertoire of HA-binding proteins (hyaladherins). Many hyaladherins contain a common structural domain, termed a Link module, which is involved in ligand binding. The most important member of the Link module superfamily is the main HA receptor, CD44. CD44 has diverse functions including not only the organization and metabolism of extracellular matrix, but also engage the cytoskeleton and co-ordinate signaling events to enable the cell responce to changes in the environment. HA has an extraordinary high rate of turnover, and at the cellular level it is considered to be degraded progressively by a series of enzymatic reactions that generate polymers of decreasing sizes. HA biological effects are known to be determined by the polymer size and depend on the cell type. For example, the native high molecular weight HA is anti-angiogenic, while its degradation products (6-20 saccharides) stimulate endothelial cell proliferation, migration and differentiation. In contrast, these fragments inhibit the proliferation of vascular smooth muscle cells, whereas high molecular weight HA promotes cell growth and migration. The dysregulation of HA metabolism is a typical feature of diabetes complications, and increased glucose level is considered to be the main cause of this phenomenon. The HA depolymerization due to the effect of free radicals and advanced glycation end products leads to the vitreous body liquefaction, and may be the reason of the proliferative retinopathy in diabetes. The enrichment of extracellular matrix with high molecular weight HA under the action of high glucose level was demonstrated for vascular smooth muscle cells, skin fibroblasts, endothelial and mesangial cells. This effect is considered to accelerate the development of atherosclerosis stimulating the proliferation of vascular smooth muscle cells, and to promote the transformation of acute wounds into chronic ulcers deepening the pathological state of dermal fibroblasts in diabetes. And, on the contrary, the accumulation of high molecular weight HA on the surface of endothelial cells may have positive value for the glycocalyx integrity. Since high molecular weight HA is known to possess the anti-inflammatory and anti-fibrotic effect, the enrichment of mesangial matrix with it may represent an endogenous mechanism to limit renal injury in diabetes. Thus, the investigation of HA metabolism in diabetes mellitus emphasizes the dependence of HA biological effects on cell type and demonstrates the importance of this molecule for tissue homeostasis.

Comparative characteristic of thiamine antagonists on apoptosis induction in different types of nerve cell lines.

Abstract: Abnormalities in oxidative metabolism and inflammation accompany many neurodegenerative diseases. The mechanisms of neurodegeneration induced by thiamine deficiency remain incompletely elucidated. The susceptibility of various types of nerve cells to thiamine (vitamin B) antagonists--oxythiamine (OT), pyrithiamine (PT) and amprolium (Am) was investigated. Four cell lines (neuronally differentiated rat PC-12, rat astrocytes DITNC, neuronally differentiated human SH-SY5Y and human astrocytic cells 1321N1) were used for experiments as neural cell models. When different cell types were cultivated with thiamine antagonists, a significant decrease of viability was detected in a time- and dose-dependent manner as demonstrated by the WST-1 colorimetric assay. These data were similar to those of caspase 3 activity and DNA fragmentation induced by thiamine antagonists. All tested cell lines were more vulnerable to OT and PT than to Am. Am displayed a pronounced damaging action on neuronal cells and had a modest influence on astrocytes. The last observation gives the basis to suppose, that neuronal cells need external arrival of thiamine more than astrocytes. Thus, the results testify that various types of nerve cells have different susceptibility to the thiamine antagonists and this relates to extent of apoptosis development.

[Oxidative modification of proteins, its role in pathologic states].

Abstract: Generalized literature data covering principal mechanisms of oxidative modification of protein and its role in various pathologies are presented in the paper. It is emphasized that due to peculiarities of protein structure organization the process of oxidative modification is of complicated and specific character, which is determined by amino acid composition of the protein. Oxidative modification of protein can be connected with impairment of not only a polypeptide chain itself, but also particular amino acid residues with formation of several types of radicals. Mechanisms of formation of long-life hydroperoxides and their role in oxidative stress are discussed. The role of electron-transfer (migratory) reactions in formation of radical centers on a protein molecule surface is elucidated. Oxidative modification of protein is considered as a process of regulation of their synthesis and degradation connected with activation of multicatalytic proteases. Oxidative destruction of protein is one of early and most reliable markers of tissue lesion in reactive species pathology.

Expression of mouse 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 mRNA alternative splice variants in hypoxia.

Abstract: Expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB-3) mRNA alternative splice variants was studied in different mouse tissues in hypoxic conditions in vivo. Significant increase of the expression of PFKFB-3 mRNA was observed in the mouse lungs, testes and brain in hypoxia. Several new alternative splice variants of PFKFB-3 mRNA were identified in the lung, testis, brain and skeletal muscle. They have different length and amino acid sequence of C-terminal regulatory part. However, 6-phosphofructo-2-kinase and fructose-2,6-bisphosphatase catalytic domains were identical. Moreover, the expression of different alternative splice variants of PFKFB-3 mRNA has shown tissue specificity and different levels of induction in hypoxic conditions in vivo. Results of this investigation indicate a possible role of PFKFB-3 splice isoform in cell adaptation to hypoxic conditions.

[The role of mitochondrial permeability transition pore in transmembrane Ca2+-exchange in mitochondria].

Abstract: Ca2+-uptake accompanied with mitochondrial permeability transition pore (MPTP) opening is studied in rat liver mitochondria. In conditions of MPTP opening, as well as in conditions of MPTP blockage by cyclosporine A (CsA), Ca2+-uptake in mitochondria is counterbalanced by proton efflux into incubation medium. Independent of MPTP opening, observed stoichiometry of this exchange is 1Ca2+ : 1H+. MPTP opening dramatically decreases Ca2+-uptake in mitochondria: from approximately 400 nmol/mg protein in the presence of CsA to approximately 80-100 nmol/mg protein due to the increased mitochondrial membrane permeability. In the absence of CsA Ca2+-uptake is accompanied by the insensitive to Ca2+-uniporter blocker, ruthenium red (RR), release of Ca2+ from mitochondria which corresponds to as well RR-insensitive, but sensitive to CsA uptake of H+ into mitochondrial matrix. This calcium-proton exchange resulting from MPTP opening is observed only when Ca2+ uptake into matrix exceeds some basal level. The data are consistent with an assumption that, contrary to Ca2+-uniporter, MPTP has its own proton conductance. MPTP opening provides exchange of Ca2+ between mitochondria and medium which is coupled to the counterflow of protons into matrix space. Obtained data elucidate the physiological role of MPTP as regulatory mechanism for control of Ca2+-uptake level and intramitochondrial pH.

Elastolytic activity of bronchoalveolar lavage fluid in acute lung inflammatory injury

Abstract: Elastolytic activity in bronchoalveolar lavage fluid in the lung with acute inflammatory injury and properties of different proteinase inhibitors for its correction was established. It was determined, that 4/5 of elastolytic activities are submitted to neutrophile serine proteinase (EC 3.4.21.37) and 1/5 of elastolytic activities - metalloenzymes macrophages origin (EC 3.4.24.65). Inhibition of elastase-like activity with the use of three proteinase inhibitors: contrycal, ingiprol and thermo- and acid-stable proteinase inhibitor from rabbit blood showed more intensive ability of thermo- and acid-stable proteinase inhibitor to inhibit pancreatic elastase and pull of neutrophil and macrophage elastase. Preventive use and treatment of proteinase inhibitors effectively suppressed activation of proteinases in the acute lung inflammatory injury.

[Cytochrome P450 2E1 expression in mice liver after exposure to continuous and acute gamma-radiation].

Abstract: The effect of continuous low-intensity and acute high-intensity ionizing radiation in low and high doses on expression of cytochrome P450 2El (1.14.14.1) in mice liver was studied. It was shown, that changes of Cyp2e1 amount depended on the dose and intensity of ionizing radiation. Low doses of continuous gamma-radiation caused reliable decrease of Cyp2e1 expression on protein mRNA levels. Low doses of acute gamma-radiation lead to an increase of Cyp2el amount, while high doses--to a corresponding decrease. We showed, that low and high doses of acute gamma-radiation caused a significant decrease of Cyp2e1 mRNA level. We suppose that the detected changes of Cyp2el expression are associated with peroxidation process and development of oxidative stress.

[Immunosuppressive characteristics of N-stearoylethanolamine a stable compound with cannabimimetic activity].

Abstract: Results of investigation of biochemical mechanisms of N-stearoylethanolamine (NSE) influence on the processes of allergic responses of immediate and delayed type (anaphylactic shock in guinea pigs and contact hypersensitivity to 2,4-dinitrochlorobenzene in mice) are presented in the paper. NSE was given per os during two weeks. It was found that in anaphylactic animals, NSE prevented the growth of histamine levels in the heart, kidneys and spleen, suppressed NO2(-) level increase in these organs and promoted its normalization. At the same time NSE prevented the decrease of the level of stable metabolite of nitrogen oxide - nitrite-anion (NO2(-)) in the liver and to a lesser degree in the lungs, and also decreased the activity both inducible and constitutive NO-synthases. NSE normalized the content of TBA-reactive products in the lungs and decreased it in the heart, diminished the decline of activity of glutathione peroxidase, catalase and superoxide dismutase. Effects of NSE depended on its daily dose. About 70% of animals which received NSE in a dose 65 mg/kg of body weight had no fatal outcome after the induction of anaphylactic shock. NSE suppressed the delayed type hypersensitivity response and normalized NO2(-) content in the blood plasma of mice but only at the dose of 50 mg/kg of weight. In the thymus of sensitized mice NSE diminished the content of NO2(-). Thus, though NSE has no affinity for specific CB receptors, in other words, it is not a typical endocannabinoid, its ability to influence the immediate and delayed type allergic reactions opens a perspective for creation of new medications which differ principally from existing pharmacological drugs with anti-allergic and immunosuppressive properties.

[tRNA-dependent editing of errors by prolyl-tRNA synthetase from bacteria Enterococcus faecalis].

Abstract: Maintenance of amino acid specificity by aminoacyl-tRNA synthetases, particularly prolyl-tRNA synthetase, requires for not only specific recognition of homologic amino acid, but also missynthesized products hydrolysis, known as editing. The speeding-up of the enzymatic hydrolysis of missynthesized alanyl adenylate by bacteria Enterococcus faecalis prolyl-tRNA synthetase in the presence of tRNAPro, and also importance for this function of 2'- and 3'-hydroxyle groups of tRNA 3'-terminal adenosine ribose is shown in the work. Furthermore, results are shown, that support the absence of editing (INS) domain role in alanyl adenylate hydrolysis. Possible significance of tRNA-dependent alanyl adenylate hydrolysis by prolyl-tRNA synthetase for prolyl-tRNAPro synthesis specificity maintenance is discussed.

[Use of flow cytometry to determine Ca2+ content in mitochondria and influence of calmodulin antagonists on it].

Abstract: Ca ions accumulation in isolated myometrium mitochondria was investigated using flow cytometry and fluorescent probe fluo 3-AM. The addition of 1 mM of Ca2+ and 5 microM of A23187 to the incubation medium resulted in the shift to the right of geometrical peak position of fluorescence probe intensity compared with that registered in the absence of Ca ions. The increase of Ca concentration in the medium resulted in the increase of fluorescence intensity. In the conditions of Ca(2+)-uniporter functioning modelling the probe fluorescence intensity also increased depending on an increase of Ca concentration and did not change at primary presence of the 1 microM CCCP. Ca2+ accumulation in mitochondria was completely inhibited by 10 microM calmidazolium or 100 microM trifluoperazine, known as calmodulin antagonists. It was also shown that these calmodulin antagonists caused mitochondria membrane depolarization. The membrane potential was measured using fluorescent probe TMRM. It is supposed that the inhibitory action of calmodulin antagonists on Ca ions accumulation in myometrium mitochondria can occur due to direct inhibition of Ca(2+)-uniporter and/or due to membrane potential dissipation.

Cyanidin as endogenous chelator of metal ions in maize seedling roots

Abstract: The property of cyanidin complexation with different metal ions in maize seedlings roots was established using parameters of reflectance spectroscopy and colorimetry. The spectral criteria of pigment association with metals in vivo were evaluated.

[Intramolecular double-stranded helices of polyadenylic acid and their possible biological significance].

Abstract: Under protonation of the single-stranded polyadenylic acid so called "frozen" form arises simultaneously with formation of two double-stranded forms. It has been shown that a portion of the polyadenylic acid "frozen" form increases with the size of poly(A) and ionic strength of solution, i. e. with an increase of polymer chain flexibility. These findings may be considered as evidences in favor of our earlier supposition on poly(A) ability to fold with formation of intramolecular double-stranded helices. Ten years ago we also proposed a hypothesis that such double-stranded helices can be formed in poly(A) tracts of cellular RNAs and they can participate in several biological processes. An analysis of literature data published later evidences for the hypothesis adequacy and shows that it still remains urgent.

[A model of three-dimensional structure of Mycobacterium tuberculosis tyrosyl-tRNA synthetase].

Abstract: The search of new effective antibacterial drugs against infectious agents also lately include inhibitors of some aminoacyl-tRNA synthetases. In this regard, tyrosyl-tRNA synthetase from M. tuberculosis (MtTyrRS) is one of especially attractive target due to its key role in cell metabolism and significant differences between spatial structures of eubacterial and human TyrRSs. In this article the theoretic homology modeling of spatial structure of catalytic module of MtTyrRS (region Met1-Ser321) has been carried out based on experimentally determined structures of homologous TyrRSs from other eubacteria, and the comparison of the structures of their active sites was performed. Most of MtTyrRS catalytic site residues, particularly those, which form special hydrogen bonds with low-molecular-weight ligands (Tyr36, Asp80, Tyrl71, Asp178, Gly194 and Asp196) as well catalytic residues Lys231 and Lys234 from KFGK motif of interdomain loop and Arg87, are conservative in evolution.

The effect of pesticide acetamiprid on biochemical markers in tissues of fresh water bivalve mussels Anodonta cygnea L. (Unionidae)

Abstract: The effects of ecological real concentration of pesticide "Mospilan" (active substance - acetamiprid) on the status of oxidative stress biomarkers, neurotoxicity and metallothioneins' (MTs) characteristics of freshwater bivalve mussels Anodonta cygnea were investigated. The prooxidative changes (decrease of superoxide dismutase activity, reduced glutathione content, increase of content of lipid and proteins peroxidation products) and decrease of the MTs content in gills and especially in digestive gland in the experimental group were reflected, whereas acetylcholinesterase activity was not changed. The effect of acetamiprid induces the appearance of additional chromatographic MTs form.

Fluorescein transport and antioxidant systems in the yeast Saccharomyces cerevisiae under acid stress

Abstract: The influence of acetic acid induced stress on the activity of fluorescein extrusion system and cell survival in the yeast Saccharomyces cerevisiae has been studied. It was shown that acetic acid caused the inhibition of fluorescein efflux from the cells of both parental strain and its derivative defective in the transcriptional factor War1 which regulates the system of acetate efflux from the cell. The stress induced by 200 mM CH3COOH decreased almost 10 times the survival of strains deficient in the regulatory proteins War1 and Yap1 as compared with respective wild strains. However, pretreatment of the yeast by sublethal concentrations of hydrogen peroxide resulted in the increased resistance to acid stress. Thus it may be supposed that several systems exist which are responsible for acetate extrusion from the yeast cells. Regulatory proteins War1 and Yap1 are involved in the yeast adaptation to the stress induced by acetic acid.

Acid stress in yeast Saccharomyces cerevisiae

Abstract: The data concerning the influence of weak organic acid on microorganisms, particularly yeast Saccharomyces cerevisiae are summarized in the work. The main pathways of weak organic acid arrival into the cell and their metabolism are presented. Responsible mechanisms of microorganism's resistance to the action of weak acids are described. The information regarding the role of H+-ATPase, ABC-transporters and antioxidant enzymes in yeast during acid stress adaptation is given. Special attention is paid to the role of a transport protein Pdr12 and its transcription factor War1 in the response of S. cerevisiae to the stress induced by high concentration of weak organic acid anions in the cell.

Noninvasive monitoring of the hepatocellular carcinoma growth by the method of 1H and 23Na nuclear magnetic resonance

Abstract: Using diffusion weighted 1H, single-quantum 23Na and triple-quantum-filtered 23Na magnetic resonance imaging water apparent diffusion coefficient (ADC), total tissue Na+ and intracellular Na+ were monitored in hepatocellular carcinoma (HCC) in rats and in the surrounding liver tissue. The tumor water ADC was approximately 50% higher compared to the nearby healthy liver tissue but did not increase during 28 days of tumor growth (double time 3.9 days). The HCC growth was associated with an increase in both total tissue and intracellular 23Na signal intensity especially after 21 days post-cell inoculation reflecting possible changes in extracellular space and in intracellular ionic metabolism.

[Role of alpha-tocopherol in oxidative stress of rat thymocytes induced by hydrogen peroxide and menadione].

Abstract: T paper deals with studying the effect of alpha-tocopherol and its analogues (alpha-tocopheryl acetate and alpha-tocopheryl quinine) showing no antioxidant properties on rat thymocytes survival and intracellular content of reactive oxygen species (ROS) at H2O2 and menadione-induced oxidative stress. It is established, that the ability of alpha-tocopherol to inhibit the thymocytes destruction induced by the development of oxidative stress is insignificant. It does not depend on the presence of free OH-group in the structure of alpha-tocopherol molecule responsible for development of antioxidant properties, and does not correlate with its influence on intracellular ROS content. The efficiency of the glutathione synthesis predecessor N-acetyl-L-cysteine in the given model testifies to the involving of other systems of antioxidative protection in these processes. The obtained data allow to conclude, that alpha-tocopherol does not play the main role in the protection of cells against ROS damaging action that calls into question its ability to prevent the oxidative stress.

Functioning of tyrosine protein kinases and phosphatases in gastric mucosa cells under conditions of oxidative and nitrosative stress in gastric lesions

Abstract: Acute cold stress caused lesions of gastric mucosa as a result of its attack by active oxygen and nitrogen compounds. The tissue regeneration is regulated by a cascade of tyrosine protein kinases. Gastric ulceration leads to a decrease in activity of tyrosine protein kinases and phosphatases, following by fall in phosphotyrosine content in proteins of plasma membranes of gastric mucosa cells. No changes in superoxide dismutase activity, slight increase in catalase activity, inhibition of glutathione peroxydase, significant increase in OH* content and decrease in zinc level were observed in the gastric mucosa cells of stressed rats. That increased oxidative damage can lead to inactivation of protein tyrosine phosphatases. Nitric oxide synthase activity was three times higher in gastric mucosa cells after the cold stress. That can promote nitrosylation of tyrosine residues. During following days nitric oxide synthase activity remains high. Superoxide dismutase is activated on the 4 and 5th day after the stress. Catalase activity normalizes after second day. Tyrosine protein kinase activity increases in membranes with maximum on the 4th day, and remains inhibited in cytosole. Tyrosine protein phosphatases keep inhibited as well. Gluthatione peroxydase activity and zinc level decreased on the 5th day. Obtained results can be the evidence of violations in signal transduction through protein tyrosine kinase cascades, due to the reduction in tyrosine phosphorylation, as a result of increase in the content of active oxygen and nitrogen species.

Comparative characteristics of lactate dehydrogenase from the liver and white muscles of common carp (Cyprinus carpio)

Abstract: Lactate dehydrogenase from the liver and white muscles of common carp (Cyprinus carpio) was purified by the differential precipitation of supernatants with ammonium sulfate. The results of native electrophoresis of partially purified lactate degydrogenase (LDH) and LDH from some tissues exhibited the different isozyme composition there. However, the kinetic properties of these isozymes from two tissues were not different, except for the value of K(m) for pyruvate, which was 72.5 +/- 11 and 217 +/- 32 microM for the liver and muscle, respectively. LDH from the liver and white muscle had similar pH-dependences with pH-optima for the both LDH activities between 6.75 and 8.00. But studied isozymes demonstrated different thermostability. The partially purified LDH from the liver showed 450% activity after 2 h at 50 degrees C. In contrast, the partially purified LDH from the muscle exhibited about 300% activity after 3 h at 65 degrees C. The heating of partially purified LDH from the muscle caused complete purification of this isozyme.

Effect of metal microelements on biochemical indices of probiotic bacteria

Abstract: The influence of metal-microelements (Zn, Cu, Ag, Au) in colloid and ionic form on the main biochemical parameters (ATP-ase activity, transmembrane potential and respiratory activity) of E. coli G35 N#1-413 and Ent. faecalis G35 N#4-410 probiont-strains has been studied with the goal to create complex metal-bearing probiotic preparations. Monotonous dose-dependent inhibitory influence of all mentioned metals in ionic form on the bacteria functional activity has been established. Metals' colloids had certainly stimulating influence on microorganisms' biochemical parameters in the same concentration limits with the following maximum positive effects: for Zn - 2x10(-7)-2x10(-4) mg/ml, for Cu - 8.4x10(-7)-8.4x10(-6) microg/ml, for Ag - 23x10(-7)-23x10(-4) microg/ml, for Au - 5x10(-6) microg/ml by metals. It has been shown, that cultural characteristics of probiont-bacteria in the presence of both ionic and colloid forms of studied metals remain stable. Certain stimulation of probiont-bacteria' main enzymes and life-support processes by colloidal forms of the studied metals-microelements in determined concentration and particle dimension limits is the evidence of a possibility of metals' colloids application in probiotic preparations' composition in order to increase the resistance and functional activity of probiont-microorganisms.

Influence of cattle cord blood fraction below 5 kD on biochemical parameters of blood in experimental chronic stomach ulcer in rats

Abstract: Influence of cattle cord blood fraction (below 5 kD) on lipid peroxidation product content and alkaline phosphatase activity-in peripheral blood was studied on the experimental subchronic stomach ulcer model in rats. It has been shown that the fraction administrations normalize thiobarbituric-active product content and alkaline phosphatase activity in blood, which testifies to decreasing inflammatory reaction in the mucous membrane of the stomach. The fraction administrations accelerate the processes of regeneration of the mucous membrane of the stomach up to complete healing of ulcer defects. Cord blood fraction below 5 kD from cattle possesses antiulcer activity which is analogous to the actovegin activity. It has been shown by gel-penetrating chromatography that the pattern of cord blood fraction low molecular substances is different from the actovegin pattern both qualitatively and quantitatively.

[Effect of 2,4-dinitrophenol on the rat liver respiratory activity and ATP content after hypothermic storage and following reperfusion].

Abstract: The influence of oxidative phosphorylation uncoupler 2,4-dinitrophenol (DNP) presence in preserving solution on the rat liver respiratory activity and ATP content after 18 h of hypothermic storage (HS) and following normothermic reperfusion (NR) was investigated. DNP presence on the HS stage led to decrease of ATP level as compared with the control. After DNP removal during NR the gradual recovery of oxidative phosphorylation coupling occurred. This fact resulted in improvement of mitochondrial functional state (V4 respiration rate decrease, respiratory control and ATP level increase).

[Effect of phosphatidic acid on the reaction of linoleic acid oxidation by 5-lipooxygenase from potatoes].

Abstract: Influence of anionogenic phospholipid of phosphatidic acid (PA) on oxidation of linoleic acid by 5-lipoxygenase (5-LO) from Solanum tuberosum was studied. The influence of PA was studied in micellar system which consisted of mixed micelles of linolenic acid (LK), Lubrol PX and different quantity of enzyme effector PA. The reaction was initiated by addition of 5-LO. It was established that 5-LO had two pHopt. in the presence of 50 microM phosphatidic acid: pH 5.0 and 6.9. In concentration of 50 microM PA was able to activate 5-LO 15 times at pH 5.0. The reaction maximum velocity (Vmax) coincided with Vmax of lipoxygenase reaction without the effector at pH 6.9 under such conditions. It was found that 30-50 microM phospholipid in the reaction mixture decreased the concentration of half saturation by the substrate by 43-67%. The enzyme demonstrated positive cooperation in respect of the substrate, the reaction is described by the Hill equation. Hill coefficient value (h) of the substrate was 3.34 +/- 0.22 (pH 6.9) and 5.61 +/- 0.88 (pH 5.0), that is with the change of pH to acidic region the number of substrate molecules increased and they could interact with the enzyme molecule. In case of substrate insufficiency the enzyme demonstrated positive cooperation of PA, it added from 4 to 3 effectors' molecules at pH 5.0, that is the phospholipid acted as the allosteric regulator of 5-LO. A comparative analysis of the influence of 4-hydroxy-TEMPO displayed, that the level of nonenzymatic processes in the case of physiological pH values was lower by 15-50% in the presence of PA in the range of 30-80 microM than without the effector.

The influence of lectins on some repair processes in mammalian cells in vitro

Abstract: The influence of plant lectins on primary DNA damage repair and on expression of repair enzyme alkylguanine-DNA alkyltransferase (MGMT) in mammalian cells in vitro has been investigated. Those lectins have been shown to modify DNA damage repair process, and to induce the MGMT expression increasing its level in the used model system.