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| Scientific Researches of | |
| The scientific research carried out in Department has some directions of development. 1. One of them is the investigation of molecular mechanisms of intracellular metabolism regulation by hormones especially by steroids. Both genomic and some non genomic effects of steroids were studied in various target tissues of vertebrates. Some steroid inducible new enzymes were detected and the mechanism of their induction was investigated. The structural and functional changes of nuclei and its various structures such as nuclear membranes, nuclear matrix and chromatin were studied during the steroid induction. Although the main mechanism of steroid hormone action involves the high specificity interaction of steroid-receptor complexes with nuclear acceptor sites which leads to the induction of certain proteins some data obtained by scientists of Department show the estradiol ability to initiate as well as to modify the functioning of phosphoinositide mechanism resulting in protein modification via phosphorilation in brain synaptosomes. The redistribution among the polyphosphoinositide fractions in synaptosomes, nuclear membranes, nuclear matrix and chromatin during the steroid action were determined. The possible ways of interdependency between two mechanisms of steroid action on plasma membrane and nuclear level in various cells are studied. 2. The second direction of investigations devoted to study of the mechanisms of intracellular metabolism regulation in plant cells. These studies involve the following items. Study of phythohormones and different origin biological active substances molecular mechanisms of action. Use of the prolonged-passed cell cultures and protoplasts from different plant organisms for the receiving of the somatic hybrids. Study of the activity and isoenzyme composition of the main plant enzymes during ontogenesis and under action of the different origin biologically active substances. To reveal peculiarities of hybrid DNA received during gene engineering and cell hybridization. Definition of biologically active substances action and medicinal preparates different origin at the genetic apparatus. Definition of participation portion of parents genomes at the formation child genomes. Our preliminary results indicate on the nonequal participation of parent's genomes. 3. The third direction of investigations devoted to studies of structure of DNA and DNA-ligand complexes at different functional states of genome. Determination of DNA base composition based on the method of thermal denaturation and applying of these approaches for the investigation of properties of DNA and chromatin under the influence of factors of different origin. The investigation of chromatin, particularly the processes concerning the nucleosomal organization of chromatin during its activation under the action of biologically active substances. A new opportunity appeared to investigate the interaction of various ligands with B and Z forms of DNA. The enthalpy of the helix-coil transition of different GC-content DNAs was obtained. There have been used both integral and differential melting curves in the investigation of DNA with ligands at different origin. The theoretical and experimental study of conformational transitions of Complexes of DNA with ligands having several types of binding sites of different forms of DNA has been investigated. Interaction of ethidium bromide with single-stranded polynucleotides has been investigated. Analyses of the experimental data suggests that ethidium bromide may form at least two types of complexes with the single-stranded polymer. 4. Proton circulation through the bacterial membrane and its relation to potassium ion uptake and the other transport systems and key enzymes of anaerobic oxidation-reduction are of the interest. A hypothesis that the F0F1-ATP synthase in fermenting bacteria can associate with the K+ uptake TrkA system to form a supercomplex functioning as a proton-potassium pump has been advanced, and some evidences in favor tothis hypothesis have been obtained. Moreover, a local transfer of energy from F0F1 to TrkA is assumed to be carried out by a dithiol-disulfide interchange, reducing equivalents donated by formate through formate hydrogen lyase or by NADH, and/or proton potential are required. Regulatory pathways of such associations by one of the trk genes, the Arc system for control of synthesis of enzymes in aerobic (respiratory) metabolism as well as environmental factors (growth pH, redox potential etc) are being investigated. Although a role of these associations in cell physiology has not yet described, the two different phenomena of transport systems, associations each with other within the membrane and dual mode of operation can be general features among transport and enzymatic proteins of bacterial and the other membranes. 5. The next direction of investigations devoted to studies of free-radical peroxidation of lipids and structures contained lipids such as biomembranes by several methods of chemiluminescence, definition of MDA concentration, detection of activities of antioxidative enzymes during different pathologies. The antioxidative indexes of herbs and the comparative analysis of peroxidation level at various stages of evolutionary development of higher organisms were also studied. 6. Another direction of studies devoted to investigation of primary photophysical and photochemical processes. Study of effectiveness of primary light energy conversion in a photosynthetic plant apparatus under natural or technical air pollution is also. carried out . |
| At the department of biochemistry of YSU the main subject of research is the examination of urea biosynthesis through the main mechanism of ammonia neutralization. In our previous works the urea biosynthesis has been studied from comparative and evolutionary viewpoint to reveal the formation mechanism of ureothelism in the course of evolution. Based on this study the following viewpoint was put forward: the formation of ureothelism is conditioned by the connection of ureothelic arginase to the four enzymes which ensure the arginine biosynthesis, when it becomes biologically vital for urea to be the final product of nitric metabolism. It is known that reptiles, particularly frogs, are ammonothelic in the earlier stages of development, though all the enzymes neccessary for urea biosynthesis are found in liver, whereas after metamorphosis they turn into ureothelic organisms, that is the enzymes maintaining the urea biosynthesis start operating as a unified mechanism. Having as a basis the viewpoint put forward by prof. Davtian about the existance of ureothelic and non-ureothelic arginases in nature it was proved that the formation of ureothelism in the liver of reptiles is not the result of enzyme modification existing before the metamorphosis and their combination on that ground in the form of urea biosynthesis mechanism. It is the result of combination in the process of metamorphosis of a new enzyme of ureothelic arginase induction and the four enzymes ensuring the arginine biosynthesis. Thus it turns into a mechanism ensuring the urea biosynthesis. Our researches continue in the direction of enriching this principle viewpoint with new facts. It has been shown that the arginase isoensymes in reptile liver are essentially different before and after metamorphosis, particularly, the number of isoenzymes of argingine, their sensitivity to the reagent linking the thiolic (EDTA) and metal ions , the nature of inactivation under the influence of acid pH (because of spliting into subunits) are different. Some valuable data has been obtained, which contrary to existing opinions speak for the absence of the role of Mn++ ions in the arginine activation in mammalian liver. There is also new data concerning the activity of proline oxydase. In particular, it has been shown, that the intermediate product of the activity of this enzyme is proline-5-carboacid. The latter turnes into glutamic acid in the presence of NAD. In case of low concentrations arginine has a stimulating influence on this process. There are some very interesting results concerning the stimulation of the induction of D- and L-aminoacid oxidases, which are the enzymes ensuring thedeamination of D- and L- amino acids, previously found out by us in yeast. Particularly, the stimulating influence of a small quantity of certain fractions obtained through helfiltration of yeast homogenate on the growth of yeast, on the assimilation of D- and L-amino acids from the environment and on the induction of aminoacid oxidase. The deam nation of L-amino acids in rat liver, kidney and brain sections and homogenates was investigated. It has been shown that in sections amino acids are deaminated, whereas in sections ammonia is constantly being removed and its concentration is always low. It has been shown that in liver homogenates the aminoacids stimulate the urea biosynthesis probably after being deaminated. Some preliminary data has been obtained on the following: if in various tissue homogenates artifical conditions for ammonia linking are created (for example, the inclusion of ammonia in carbamylphosphate biosynthesis) the deamination in homogenates will also be possible. |
| Researches are being conducted into two principal fields. As per higher plants,- investigations aim at studying flora of mosses and medicinal plants, and carpo-anatomycal patterns in principal directions of mycological investigations are: revealing the biodiversity (flora, morphology, systematic) and physiology of Fungi. Accumulated material and monographic processing are reflected in 7 volume publication "Mycoflora of Armenian SSR", dedicated to orders Peronosporales, Agaricales, Aphyllophorales, Hyphales, Uredinales, Pychidiales. There have been and studied the following ecological groups of fungi: phytothrophs, geothrophores, caprothrophs predotory fungi of household and industrial fasilities, contaminants-destructers of vegetable and animal foodstuffs, medicinal and industrial materials and finished goods made of them. Their physiological activity, adaptivness to the extreme conditions of existence, significance in practical activities of man are also being studied. Special attention is paid to toxigenic activity of fungi contaminating foodstuffs and drugs. There have been worked out the State Standards according to the methods of investigation of toxigenic fungi and isolation of mycotoxins in foodstuffs and also pharmocopeic article. There has been also worked out a concept on securing safety of the food in Armenia in the period of transition to the market economy. Investigations are being conducted regarding the problem of biodestruction of industrial materials and articles made of them (glue, components, paper, pulp etc.). During last years investigations on biotechnology have been conducted. Prospective strains of bazidial macromycetes for getting food and forage biomass and drugs are technogenic extreme factors on growth, development, and physiological activity of fungi are examined. In this regard there are investigations on monitoring of ethiology of fungi- contaminants while producing foodstuffs as well as in epicentral zone of Spitak earthquake and in the vicinity of the Armenian Nuclear Power Station and a number of other industrial sites. |
| At the Department of Human & Animal Physiology by neurophysiological and neuropharmacological methods there is investigated neuronal and neurochemical organization of central mechanisms of regulation of some viscero-somatic functions of organism in norm and in conditions of extremal factors influence (vibration, hypoxia, mental work etc.). It were studied neurophysiological mechanisms of functional state of different areas of cerebral hemispheres at the modelling of long-term monotonous work on the display. On the base of data received it was presented methodics recommendations for the neurophysiological and neuropharmacological correlation of nervous system functions disturbances in conditions of influence of different extremal factors. |
| ENP focuses on environmental issues such as evaluation of pollution level in ecosystems, water quality and environmental management of lake Sevan and his basin, environmental Impact assessement and biodiversity, soil protection, clean tectologies. |
| From 1996 researches are being conducted into two principal fields. At the Department of Genetics and Cytology and Research Laboratory of Cytogenetics the monitoring of Armenian Nuclear Power Plant is continued. It includes the genetic monitoring of Nuclear Power Plant workers, and also its environment: plant populations and sewage water and ambient air (by sensitive model indicator of environmental pollution- clones of Tradescantia). We are summarizing the results of Chernobyl accident liquidators from Armenia genetic and cytogenetic research for the presence of clastogenic factor in their blood, that can cause chromosome aberrations and DNA damages, detected by "Comet assay" technique (single cell electrophoresis). Earlier for few years was conducted cooperative research with Paris VI University (Dr. I Emerit) on cytogenetics of Chernobyl Armenian liquidators. It gave practical results on the treatment of liquidators by means of antioxidants. Also the genetic mechanisms of the Familial Mediterranean fever are investigated. The role of free-radical processes in the revealed genetic defects is demonstrated. The final goal of research is the formation and testing of complex system of population and individual estimates in the groups of genetic risk . |
| The members of the Department conduct investigations directed to the elucidation of the role of hybridisation for the formation of species; specify the composition of species of Cheiroptera, study some questions of their biology; carry out the zoogeographical analysis of parasite fauna of fishes in the reservoires in Armenia; study some questions of ecology and bioacoustics of widely-distributed amphibia in Armenia. New for Armenia species of bees and parasites of fishes, reptiles, cheiroptera are described. At the Department the influence of the anthropogenic factor on the populations of fishes in the Lake Sevan is studied as well. The work on improvement of biotechnics of the marketable fish-breeding of some fishes in the reservoires of Armenia is carried out. Some regularities of restoration and compesatory-adaptive processes during post-traumatic regeneration of internals of various vertebrates are revealed by means of histological, histochemical and morphometric investigations ;support-motor apparatus of mouselike rodents are also studied). |
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