Vol. 42 No. 2 (216) (2008)

The interaction of molybdenum (VI) with citric acid is studied by the methods of ion exchange and spectral photometry. It is determined that the complex formation takes place in discrete steps to MoO$^{2+}_2$  HC₆H₅O$^{2-}_7$  equal to 1:1 and 1:2 at ionic force μ=1 and at temperature 20℃. Stepwise and general stability constants for the complexes are defined.

Rhodium (III) interacts with thionine yellow in hydrochloric acid solutions. The formed ion associate could be extracted by the dychlorethan–carbon tetrachloride (2.5 + 2.5) plus aceton (5 mL) mixture, maximal extinction is observed at the value of wavelength 588 nm. Optimal acidity of aquas solutions is pH 1.0 by HCl. The optimal quantity of dye is 1.2–1.8 mL of 0,05% solutions. The coefficient of extraction is 98.6%. The range of determined concentration is 2.2–35.1 mcg of Rh(III) in 10 mL of aqueous phase. The value of seeming coefficient of thionine yellow tetrachlorrhodiate (III) ionic associates organic extracts molar extinction  $\epsilon_{588}=$1.05·10⁴ L ·mol^-1· cm^-1 . The molar ratio beetwin thionine cation and tetrachlorrodiate (III) is 1:1.

The interaction of platinum (II) with iodide has been studied by means of spectrophotometry method. The optimal conditions for determination (medium acidity, iodide concentration, and the optical density maximum value development period) have been determined. The possibility of spectrophotometric determination of platinum (II) in the presence of palladium (II) has been shown. The relative error of determination does not exceed 5.2%.

Synthesis of benz-substituted 2-methyl-3-alkyl-4-quinolines thiuronium salts was accomplished by the interaction of 2-methyl-3-alkyl-4-chloroquinolines with thiocarbamide. The alkaline hydrolysis of these compounds results to corresponding 2-methyl-3-alkyl-4-mercaptoquinoline.

Influence of Vipera lebetina obtusa venom on level of free-radical oxidation of homogenates and lipids, purified from nervous tissue of poikilothermal and homothermal vertebrates was studied using chemiluminescence and spectrophotometric measurement of malonic dialdehide concentration. It was shown that action of toxin leads to inhibition of this process, which probably is accounted for antioxidant mechanism of interaction. Manifestation of this effect is not similar for every of studied organisms. This phenomenon may be related to the degree of saturation in fatty acids of lipids in researched tissue of different vertebrates.

Melting of DNA and it complexes with ethidium bromide (EtBr) and Hoechst 33258 has been carried out at μ=2·10^-3 and μ=2·10^-2 M Na⁺ ionic strength of solution. It is revealed, that specificity of Hoechst 33258 to the AT sequences is observed at μ=2·10^-2 M Na⁺ ionic strength, whereas decreasing of ionic strength in one order leads to disappearance of specificity. It is shown that EtBr doesn’t show specificity to the obtained sequences in the same conditions.

Comparative research of melting of complexes cis-dichlordiamineplatinum and cis-dichlordiaminepalladium with DNA is carried out. It is revealed, that melting temperature – Т_m of complexes of DNA with both compounds at low concentrations grows, while at increase of concentration of these compounds on the contrary, Т_m decreases.

Some heavy metal resistant thermophilic bacilli isolated from samples of silt of Lake Yerevan and thermal mineral source of Hankavan have been investigated. The stability of isolated cultures was demonstrated in the presence of 1 mg/L Cu⁺⁺, Zn⁺⁺, Cd⁺⁺ and Ni⁺⁺ ions in growth medium. On the basis of the complex of morphological, cultural, physiological and biochemical properties the taxonomical position of isolated cultures was established.

Isolated cultures of A. genevensis collected from different altitudes of mountain Aragats were obtained. Comparative research of tendency of calliformation and regeneration of plants from obtained calli was done.

Persistence of entomopathogenic bacteria on the leaves of apple tree after spray has been studied. By experimental data it was established that insecticidal strains are maintained no more than two months, without losing their ability to produce spores and entomocide crystals.

The genotoxicity of 5 samples of waters of r. Hrazdan and r. Marmarik were investigated with the use of Tradescantia clone 02 somatic mutations stamen hairs (SH) and micronucleus (MN) testing. It was found out that during the three months of investigation the highest level of somatic mutation was observed in SH watering from r. Hrazdan in Hrazdan city and in MN – from r. Hrazdan in Yerevan City. The results approve that the mentioned tests can be used to value the genotoxcity of water enviroment pollutants.

The article presents the list of wild growing fruit and berry plants of Armenia, made up in accordance with existing literature and own investigations. There are 17 families and 59 species of fruit and berry plants, growing in Armenia. The table shows existing fruit-consumption levels (widely consumed and sold in markets, locally used by population for personal needs, potentially usable), the usage of the plants in scientific and folk medicine and representation in the Red Book of Armenia is marked in the table as well.

In this work the effect of porphyrines, AgTOEtPyP, on the cell population kinetics was studied in vitro using morphological and biochemical techniques. The results suggested that AgTOEtPyP action consisted in the simultaneous suppression of the cell growth and activation of the cell death. About 40% of the cells were shown to die via apoptotic pathway. So, the porphyrin studied may be attributed to inducers of both necrotic and apoptotic processes. The results obtained support our previous assertion that AgTOEtPyP may be considered as a potential chemotherapeutic agent.

The micronucleus (MN) level in exfoliated buccal mucosa cells of women from Yerevan and Aragatsotn region of RA was observed. The results revealed that the MN level in two studied groups didn’t show statistically significant increase during the investigated periods (2005 and 2006). Nevertheless, the tendency of increased level of MN was observed in women from villages.

We have conducted the following investigations: inventory of discovered in Armenia ectomycorrhizal fungi, the biogeographic and genetic research of some species of Inocybe. The genus Inocybe is emphasized in the phylogeographic work, because of its abundance and importance to forests. It has been revealed 29 species, from which 20 are ectomycorrhizal fungi and 9 – humus saprotrophs. As a result of taxonomic study the detailed database for Inocybe is created.