Vol. 37 No. 3 (202) (2003)

Analysis of literature data concerning the solvent influence on some benzoylperoxide–amine reactions rate constant using solvents empiric polarity parameters has been done. It has been taken into consideration solvents ability to solvate reagents either as nucleofiles or as electrophile. When the considered peroxide–amin reaction occurs by radical mechanism the solvent acts as nucleophile, but in the case of nonradical mechanism (molecular, ionic) the solvent’s electrophile property prevails. It has been established that in those reactions the β₂ and π* descriptors reflect the nonspecific solvation effects.

Ionic state of Re(VII), Mo(VI), V(V) and W(VI) ions in mineral acid solutions has been studied using “Fixion-50” cationite fixed layers depending on nature of acids, their concentration and activation of ionite layers. The ranges of acidity and concentration where ions exist in the definite ionic state were specified by using ion-exchange thin-layer chromatography method. It has been shown that the indicated version of chromatography has some advantages in comparison with column ion-exchange chromatography method – expressness of carrying out experiments, simple instrumental requirements, reproducibility, reliability and accuracy of results. New methods for separation of above mentioned elements’ mixtures have been elaborated.

An interaction spectrophotometric between tellurium(IV) with phenylthiourea has been studied by spectrophotometric and amperometric methods. It has been shown that complex compound is formed with 1:4 molar ratio of components. The optimal conditions of the reaction: acidity, ranges of the submitting to the main laws of spectrophotometry and amperometry have been revealed.

N-Derivatives of isatin have been synthesised by interaction of its sodium salt (I) with various dihalogencontaining compounds (II–IV). 4-(N-isatinomethyl)-4'-chlormethyl-diphenylether (V), 4,4'-bis-(N-isatinomethyI)-diphenylether (VI), 4-(N-isatinomethyl)-4'-chlormethyl-diphenylketone (VII), 4,4'-bis-(N-isatinomethyl)-diphenylketone (VIII), 4-(N-isatinomethyl)-4'-chlormethyl-diphenylthioether (V), 4,4'-bis-(N-isatinomethyl)-diphenylthioether (VI) have been obtained.

The optimal conditions for maximal extraction of proteins, during which about 65 per cent of total amount of protein is extracted, have been estimated. The acid hydrolysate of precipitated proteins has been obtained and its amino acid composition has been determined. It appeared, that the yeasts Sacch. cerevisiae (the wastes of beer production) have rich amino acid composition and can be used as a source of amino acid mixtures.

The content of total nitrogen and amino acid composition of proteins (both free and structural amino acids) for some representatives of mossies section was investigated. This field was studied till now insufficiently. Some patterns of quantitative expression of amino acid composition were revealed as well as the differences between species were marked in amino acid composition.

Approaches to improve phenylalanine-producing strains in Corynebacterium lactofermentum based on precursor fluxes increasing towards biosynthesis of the mentioned amino acid have been studied. Mutations in enzymes involved in piruvate metabolism were shown to effect phenylalanine productivity.

The mutagenic activity of subterranean waters from two bore-holes in Ararat valley used both for drinking and irrigation was investigated. The frequency of somatic recessive mutations in stamen hair and micronucleus in tetrades was determined by using the clone 02 of Tradescantia. It is revealed the increase of the recessive mutations frequency is 4.4–5.4 times higher and for the quantity of mucronucleei is 1.4–1.5 times higher in comparision with the control. Changes of mutations frequency were registered dependent on the depth of bore-holes water, and on the Na⁺ ions concentration in them.

The problem of brain’s guarantee features of fulfilment of maze-model tasks at left-handeds is considered in this article. The outcomes of testing on unverbal intelligence have revealed, that 90% of the examinees was characterized by the Raven's test high IQ, and 70% – executed the offered task with high efficiency. It is shown that the brain maintenance of effective fulfilment maze-model task at the left-handed examinee is carried out at the expense of left occipital and right frontal and parietal areas.

The features of EtBr complex-formation with DNA are investigated. It is shown, that the chromophore ring of ligand can be inserted into a plane between the next bases in one of strands of double-stranded (ds-DNA) (semi-intercalation complex). The binding curves by semi-intercalative interaction of EtBr with DNA are obtained and the parameters of interaction binding constant (K) and the number of the bases (n), corresponding to one binding site, are determined. It is revealed, that EtBr may bind with completely denatured, single-stranded (ss) DNA, thus, the mechanism of interaction of ligand with ss-DNA also has semi- intercalative character, and the binding parameters  K and n coincide with those received at semi-intercalative interaction of EtBr with ds-DNA.

Purifying of ornithine cyclase has been realized by dialysis with following fractionation on sefadex G-I00. It has been discovered that enzime of haricot beetlefly loses its activity during dialysis, but larvas enzime is rather stabile and considerably active than the enzime of beetles. During fractionation of cell-free extracts of larvas and beetles on sefadex G-100 ornithine cyclase of beetles is elutioned with one peak, but larvas enzime – with two peaks possessing, rather high activity.

The analysis of UV-induced DNA damage permits to reveal the comparative sensitivity of cells towards different DNA damaging agents. The comet assay has been used to estimate spontaneous and UV-induced DNA breaks in cells of two groups of genetic risk. In cells of patients with periodic disease and Chernobyl accident clean-up workers the statistically significant increase of UV-induced levels of DNA damage compared with healthy subjects has been revealed. But the level of spontaneous DNA damage in both groups does not differ from the control one. The role of repair processes in revealed effects is discussed.