Vol. 37 No. 1 (200) (2003)

Splitting of kaolinite by the aqueous solutions of mineral acids was investigated. The modifying ability of the split products by ortofosforic acid during the development of water-resistant glues is shown on the basis of polyvinyl acetate aqueous dispersion.

By calorimetric, viscosimetric and electroconductometric methods concentric solutions of CuCl₂ (0.01–0.06 mol/L) in H₂O–dimethylsulphoxide, H₂O–diethylsulphoxide, H₂O–acetone mixed solutions have been investigated at 298 K. Physicochemical properties of these systems depend not only on solvated state of ions, but on structural peculiarities of mixed solvent too.

  An interaction between platinum(IV) iodide acidocomplex and thiazine raw organic basic dye tetramethylthionine has been studied. Compound forming in the system is extracted by dichloroetane–carbon tetrachloride (1:1) binary mixture. Maximal light absorbance (extinction) for extracts of forming compound as well as for “blind” extracts is observed at 655 nm wavelength. 

  At the optimal acidity conditions (pH 1.0 by sulfuric acid) platinum(IV) is extracted almost quantitatively (R = 97.7%) to the organic solvent phase by means of single extraction during 2 minutes’ shaking. The formed ionic associate is stable during 50 hours’ period. The optimal concentration of potassium iodide is 0.4–0.6 mL·10^–2 mol/L; optimal quantity of tetramethylthionine is secured by the addition of 1.4–2.0 mL of 0.05% solution of the dye.

  Dichloretane–carbon tetrachloride extracts of colored compound submit to the photometry main law (Beer’s law) in the range of platinum(IV) content in aqueous phase 2.49-89.59 mcg/10 mL. The molar coefficient of extinction  ε₆₅₅ = 7.65 · 10⁴ L· mol^-1·cm^-1, C_min = 0.02 mcg Pt/mL (P = 0.95).

  The influence of a series of interfering and accompanying elements on the determination of the platinum(IV) has been studied. An extraction-absorptiometric method for determination of platinum by tetramethylthionine has been elaborated.

A number of new derivatives of 4,4-dimethyl-2-butene-4-olid have been synthesized by the interaction of 2-ethoxycarbonyl-3-brominemethyl-4,4-dimethyl-2-butene-4-olid with water, hydrochloric acid and a number of nucleophile agents (hydrazine, urea, thiourea, thiosemicarbazide) as well as kalium rodanide.

  The possibility of biosynthesis of exoproteases by mushrooms Flammulina velutipes and Panus tigrinus is shown by means of selection of the appropriate nutrient medium, being the waste of a food- and agricultural industry. The tested nutrient medium, considering the addition of proper quantity of mineral components, provides optimum biosynthesis of proteases. Proteases and intracellular free amino acids, not involved in biosynthesis of proteases, are allocated in cultural liquid.

  The influence of small and large doses of Armenian adder (Vipera raddei) venom on the basic and evoked (stimulation of n. ischiadicus) electrical activity of single interneurones of lumbo-sacral area (II–VI lamines at Rexed) and focal potentials of spinal cord on intact spinal rats and rats with chronical hemisection was investigated in acute experiments. The statistical analysis on-line was done. Significant increase of fone activity rate in the beginning and following depression or pronounced late lightning of it according to the venom dose was revealed.

  Formate hydrogenlyase, an enzyme of anaerobic fermentation, has obvious evolutionary link both to the NADH:ubiquinone oxidoreductase (complex l) known as an energy conserving fragment of a respiratory chain, and the [NiFe]-hydrogenases able to translocate protons. Formate hydrogenlyase activity is also F₀F₁– ATPase-dependent both in Escherichia coli and in Salmonella typhimurium. The detailed comparison of structural and functional features of enzymes formate hydrogenlyase with having electrogenic proton pump properties allows assuming that under anaerobic fermentative conditions and under the deficiency of energy formate hydrogenlyase components, the hydrogenases, posses energy-conserving function by coupling electron transfer and proton translocation.

  Summary The effect of mannan, β-1,3 glucan and ancymidol on the activity of enzymes involved in biosynthesis of lignans, podophyllotoxin, 5-metoxypodophyllotoxin and their derivatives production in the callus culture of Linum  austriacum was investigated. The activities of L-Phenylalanine ammonia-lyase, Polyphenoloxidase, Tyrosinase, soluble Phenolase, wall-bound and soluble Oxidases were determined. Effects of elicitation on different steps of metabolic pathways in L. austriacum callus cultures were revealed.

  It was concluded that elicitors, which could stimulate the biosynthetic pathways affecting on activity of key enzymes, could stimulate the production of podophyllotoxins.

  The study of functional state of central nervous system during the computerized solution of visual-spatial task has been the subject of present research. The method of defining of time of visual-motor reaction was used. There were selected two groups of examinees on the purposefulness of reactions time alteration. It was shown that for the first group of examinees during the stable effectiveness of their activity the growth of the time of reaction was observed. That testifies the promotion of fatigue weariness. As to the second group the growth of effectiveness is being correlated by the shortening of time of reaction. It witnesses of best correlation of excited-inhibited processes in the cerebral cortex. Taking this into consideration one may suppose that for the second group of examinees this task is adequate and is not a cause for the emotional tension.

Comet assay (CA) – single cells gel-electrophoresis can be used for effective estimate of DNA damage induced by endogenous agents. In cells of patients with periodic disease the increase of spontaneous and induced by endonuclease III levels of DNA damage compared with healthy subjects has not been revealed.

By the test of determination of sterility of pollen grains is investigated the quality of male gametophyte of some species of fruit trees in the zone of Armenian nuclear power-station, about 30 km from ANPS in the zone of Noragygh village. In the population of investigated examples different formation of gametophyte generation is detected. The genotypes with high and low-moderate degrees of microgametophytes defects are isolated.

The process of thermal decomposition of hydrargyllite and pyrite has been studied using methods of thermographic and thermogravimetric analyses. It has been approved that the size of grains exerts considerable influence on the whole process of decomposition.

  An interaction of chromium(VI) with basic dye of triphenylmethane row fuxine has been studied. Formed ion associate once-through extracted by the dichloroethane from pH 1.0 to 0.5 M hydrochloric acid solutions. The ion associate is submitted to the main law of spectrophotometry in the 0.012 – 5.0 mcg/mL range of chromium contents,  ε₅₃₇ = 5 · 10⁴ ± 500  (L · mol^-1 · cm^-1). The molar ratio between chromium(VI) anion and fuxine cation in formed compound has been determined, which is 1 : 1. The determination of chromium is hindered by iron and antimony. The suggested method was applied in microgram amounts of chromium(VI) ion determination in waste waters of galvanic manufacture in soils and haricot.

The process of adenin desamination in homogenates of yeasts Candida guilliermondii NP-4, the localisation of enzyme, as well as by influence of bivalent ions Mn⁺² and Zn⁺² on the activity of adenaze of the above menthioned culture have been studied. Comparatively high activity of the enzyme is shown at 30 mcmol concentration. By method of hel-filtration the partial purification of enzyme was realized . Two protein peaks to possess the adenine desamination enzymatic activity have been found.