Effects of Gamma-Radiation on DNA Damage in Onion (Allium cepa L.) Seedlings.

The effect of γ-radiation on the level of nuclear DNA damage in onion seedlings (Allium-test) was studied using the comet assay. DNA breaks were first found in cells of onion seedlings exposed to low-dose radiation (≤ 0.1 Gy). Dose dependence of DNA damage parameters showed nonlinear behavior: a linear section in the low-dose region (below 0.1 Gy) and a dose-independent plateau in the dose range between 1 and 5 Gy. Thus, the comet assay can be used to estimate the biological effects of low-dose γ-radiation on Allium cepa seedlings.

[Apoptosis as the basic mechanism of cytotoxic action of ursolic and pomolic acids in glioma cells].

Pentacyclic triterpene acids are of great interest as compounds that exhibit selective cytotoxicity against malignant tumor cells. If earlier studies were carried out mainly in cancer cells of epithelial origin, in the present work the cytotoxic effect of ursolic and pomolic acids on the primary and permanent glioma cell lines was analyzed. Both compounds are toxic to oncotransformed cells and induce apoptosis in U-87 MG line. Using molecular docking, it has been shown that Akt1 and MDM2 may be potential targets of the studied triterpene acids. It has been suggested that ursolic and pomolic acids induce apoptosis in glioma cells through inhibition of the PI3K/Akt signaling pathway, and they can be considered as potentially promising agents for the treatment of glioblastoma.

Genotoxicity assessment of low-level doses of gamma radiation with the SOS chromotest and the Ames test.

This is the first study to present data on the genotoxicity of low γ-irradiation doses for E. coli and S. typhimurium cells obtained using the SOS chromotest and the Ames test. The most pronounced effect was recorded in the first 24 h of γ-irradiation. After 72 h in the Ames test and after 96 h in the SOS chromotest, a significant effect of γ-irradiation on bacterial cells was detected. The absence of genotoxicity at the later stages can be explained by the adaptation of bacterial cells to the conditions of exposure. The findings allow the bacterial test system to be used for studying the effects of low doses at the early stages of exposure to radiation.

[Genotoxic and Mutagenic Properties of Synthetic Betulinic and Betulonic Acids].

Synthesis of betulinic acid was performed from the birch bark extract (Betula pendula). Betulonic acid was intermediate of the synthesis. Both acids were isolated with purity 95%. Genotoxicity and mutagenicity of obtained compounds were analyzed by Ames test and SOS chromotest, none of these properties have been detected.

[Mutagenic Activity of Four Aminoazo Compounds with Different Carcinogenicity for Rat Liver in the Ames Test].

In this paper in the bacterial Ames test we compared the mutagenicity of four aminoazo compounds, previously studied by other researchers and used for activation of rat liver enzymes, with the carcinogenicity in the rat liver. It was found that in the Ames test they have mutagenic activity, however, this activity does not correlate quantitatively with rat sensitivity to their hepatocarcinogenic action. Thus, the most active carcinogen 3'-methyl-4-dimethylaminoazobenzene causes mutations almost 2.5 times less than weakly carcinogenic ortho-aminoazotoluene, and exactly the same number of mutations as non-carcinogenic N,N-diethyl-4-aminoazobenzene.

[Isolation of pomolic acid from Chamaenerion angustifolium and evaluation of its genotoxicity by microbiological tests].

Fireweed (Chamaenerion angustifolium) lipophilic constituents were investigated by GC-MS analysis. 28 aliphatic and 6 triterpenic acids were found out at first time. Pomolic acid genotoxicity and mutagenicity were analyzed by Ames test and SOS chromotest. Genotoxic and mutagenic properties of pomolic acid were not detected.

[Genetic aspects of potato resistance to phytophthorosis]. / Генетические аспекты устойчивости картофеля к фитофторозу.

Phytophthora infestans Mont. de Bary is the main oomycete pathogen of cultivated crops in the family Solanaceae, especially potato (Solanum tuberosum). Because potato is the fourth most cultivated crop worldwide, its annual losses from late blight are tremendous. Studies of the basic mechanisms of interaction between potato and the late blight pathogen not only expand the fundamental knowledge in this area, but also open up new possibilities for regulating these interactions in order to increase resistance to the pathogen. The interaction of potato and the late blight pathogen can be considered from a genetic point of view, and it is interesting to consider both the response of the potato to the colonization process by P. infestans and the change in gene activity in late blight during plant infection. We can also investigate this process by changing the profile of secondary metabolites of the host and the pathogen. In addition to fundamental work in this area, applied work in the form of the development of new preparations for protecting potatoes is of no less importance. This review briefly describes the main stages of studies of potato resistance to late blight, starting almost from the first works. Much attention is paid to key works on changing the profile of secondary metabolites phytoalexins. A separate section is devoted to the description of both qualitative and quantitative characteristics of potato resistance to the late blight pathogen: their contribution to overall resistance, gene mapping, and regulation capabilities. Both types of traits are important for potato breeding: quantitative resistance due to R-genes is quickly overcome by the pathogen, while quantitative trait loci make it possible to create varieties with almost absolute resistance due to the pyramid of effective genes. The latest approaches in molecular biology make it possible to study translatomic profiles, which makes it possible to look at the interaction of potatoes and the late blight pathogen at a different angle. It has been shown that the process of potato colonization affects not only the activity of various genes and the profile of secondary metabolites: proteins-markers of the response to infection from potatoes have also been identified: they are pathogen-bound proteins and plastid carbonic anhydrase. On the part of P. infestans, fungal cellulose synthase proteins and haustorium-specific membrane protein were markers of infection. Thus, the review contains information on the most relevant complex studies of the genetic mechanisms of potato resistance to late blight.