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The dependence of the expression level of the wheat proteinase inhibitor gene EU 293132.1 on the degree of acetylation of chitooligosaccharides and the trophicity of the pathogen was revealed. When wheat plants were infected with hemibiotrophus Septoria nodorum, high stimulating effect on the activity of proteinase inhibitors was provided by chitooligosaccharides with a degree of acetylation of 30%, and when infected with necrotrophus Bipolaris sorokiniana – chitooligosaccharides with a degree of acetylation of 65%.

We investigated the effect of presowing treatment of seeds with salicylic (SA) and jasmonic (JA) acids on the growth of wheat Triticum aestivum L. seedlings, generation of hydrogen peroxide (Н2О2) therein, and transcriptional activity of the genes encoding defense proteins—oxalate oxidase (OxO), peroxidase (PO), and proteinase inhibitor (PI)—upon their inoculation with stinking smut pathogen Tilletia caries (DC.) Tull. SA and JA were found to reduce adverse effect of T. caries on growth of seedlings and the extent of their infection by the pathogen. Improvement of plant resistance to T. caries depended on a stimulatory effect of SA and JA on the formation of Н2О2 in plant tissues and changes in activity of ОхО, PO, and catalase. SA was shown to elevate transcriptional activity of the genes of oxalate oxidase and peroxidase. We detected a considerable stimulatory effect of JA on transcriptional activity of the gene encoding proteinase inhibitor. Revealed differences in the activation of defense proteins pointed to differing mechanisms of SA and JA action on protective potential of wheat plants infected with T. caries.

This review considers the main groups of hydrolytic enzymes associated with plant pathogens, as well as proteinaceous inhibitors of these enzymes, acting as the components of plant defense system. The role of hydrolases is described in the development of a pathological process in plant tissues. Significance of hydrolase inhibitors in the development of plant resistance to pathogens is analyzed. It is proposed that specific interactions in the “host plant–pathogen” system, involving hydrolytic enzymes and their proteinaceous inhibitors, depend on the nutritional specialization of fungi.

The influence of signal molecules (jasmonic acid, phytoprostanoid oxylipins, lipopeptides of the Bacillus subtilis 26D bacterium) on the Solanum tuberosum L. potato tuber proteome was studied upon infection with the Phytophtora infestans (Mont.) de Bary phytophthorosis causative agent. Processing by signaling molecules decreased the degree of oomycete development on potato discs and caused changes in the total spectrum of soluble proteins in a pH range of 6.0–7.0 and 7.5–8.7. Differences in the differential expression of 39 polypeptides under the influence of signal molecules and infection with a pathogen were detected. It was demonstrated that the maximal protective effect upon the potato tuber infection with a pathogen is caused by the induction of protective proteins in tissues with the following values of the molecular weight/pI ratio: 24/5.8, 75/6.45, 68/6.45, 19/6.5, 69/6.3. The presence of qualitative and quantitative changes in the expression of individual proteins indicated a differential mechanism of the effect of signal molecules on the protective potential of plant cells.

The kinetics and mechanism of the reaction between uracil and hydrogen peroxide in aqueous solution have been investigated. Iron ion admixtures in the solution have been demonstrated to bring about two reaction pathways, one free-radical and the other molecular. The mechanism of the reaction has been analyzed by mathematical modeling methods, kinetic curves illustrating the variation of intermediate product concentrations have been obtained, and the rate constants of elementary reactions have been calculated.

The free-radical chain oxidation of 1,4-dioxane in the presence of an inhibitor has been investigated by mathematical modeling. The forward kinetic problem has been solved, and complete kinetic information about the reaction has been gained, including the variation of the concentrations of all reaction participants. The inverse kinetic problem has also been solved to determine the rate constants of all elementary steps.

The kinetics of the reactions of 5-hydroxy-6-methyluracil and 6-methyluracil with hydrogen peroxide in aqueous solutions has been investigated. The reactions proceed via two competitive mechanisms, namely, free-radical and nonradical ones. The iron ions present in water as impurities make possible the free-radical mechanism.

The antiradical properties of a number of uracil derivatives are studied in initiated 1,4-dioxane oxidation as a model reaction. The antioxidant activity of the uracil derivatives as inhibitors is estimated. The antiradical activity of the compounds is quantitatively characterized in terms of the effective rate constant of inhibition, fkIn.

99 A number of pyrimidine derivatives (6 methyl uracil, 5 fluorouracil, 5 hydroxy 6 methyluracil) are pharmaceuticals exhibiting a wide spectrum of activ ity. The efficacy of pharmaceuticals as antioxidants is one of the main characteristics of their biological activity. However, the mechanism of inhibition of free radical induced chain oxidation by uracils has been poorly studied. The primary event of attack of poten tial antioxidant molecule by peroxyl radical plays an important role in the mechanism of oxidation retarda tion because it affects further reaction course. It is known [1] that the free radical oxidation of virtually equimolar amounts of 2,2' azobis(2 methylpropion amide) dihydrochloride and 5 methyluracil with atmospheric oxygen for 25 h at 313 K leads to the fol lowing products