Vol 52, No 5 (2018)

Microsatellite DNA markers were used to identify and compare the genotypes of 80 samples of grapes and their presumptive parental forms. Both presumptive parental forms were confirmed for 51 samples. Further statistical evaluation showed that the probability of descent from particularly the pair of parents identified at the previous stage (X × Y) was higher than the probability of descent from any random varieties not included in the study. The X × Y index ranged from 10³ to 10¹². The identity of one of the parents was not confirmed for four samples due to nonmatching allele profiles of the microsatellite loci studied. Genotypes of the ancestral forms were used in pedigree analysis of 22 samples from the set, because plants of the presumptive parental forms were physically unavailable and there was no information on the composition of their microsatellite profiles.

Several mammalian species are resistant to diphtheria toxin (DT). The DT receptor, proHB-EGF in resistant and sensitive species, has a different primary structure due to the amino acid substitutions; however, there is no definite opinion regarding how the difference in primary receptor structure alters the process of DT internalization by resistant cells compared to sensitive. The aim of the present study was to evaluate the role of DT internalization in the development of DT resistance of mammalian cells. It was shown that L929 cells resistant to toxin and derived from the C3H mouse strain absorb the recombinant fluorescent subunit B of DT with the value of binding constant K_b that was close to that of African green monkey Vero cells highly sensitive to toxin (0.269 and 0.372 μM, respectively). Endocytosis dynamics analysis by confocal microscopy indicated that the amount of subunit B internalized by Vero varied from nearly equal (at early stages of the process) to approximately 2‒5 times bigger (after 30 min) compared to L929 cells. The obtained results suggest that, at the initial stages, DT is internalized by resistant cells as rapidly as by sensitive cells. Nevertheless, at further stages of uptake, toxin amount in cells sufficiently varies depending on the receptor expression level and physiological features of the cell culture. It was concluded that the internalization and, therefore, the resistance of cells to the DT depends insufficiently on receptor structure in resistant and sensitive species but may be dependent on subsequent endosomal transport and accumulation of DT molecules in cells at late stages of internalization.

This study presents the results and comparison of the distinctive features of the modifying effect of astaxanthin (20.0 μg/mL) on γ-radiation-induced chromosomal instability in human peripheral blood lymphocytes that were irradiated in vitro (1.0 Gy) at the G₀, S, and G₂ stages of the cell cycle. The study showed that the effect of astaxanthin on cells irradiated at cell cycle stages S and G₂ did not lead to changes in the mean frequencies and the spectrum of radiation-induced chromosomal aberrations (p > 0.05). A powerful protective effect of astaxanthin on the level of radiation-induced chromosomal instability (p < 0.001) was observed only in cells that were irradiated at the G₀ stage. Thus, the dependence of the radioprotective effect of astaxanthin on the mitotic cycle stage at which the cells were exposed to radiation was established.

The research results of studies on genome variation in triticale, which occurs during in vitro cultivation and is observed at different levels of its organization, are presented in the review. Data on alterations detected in studying the karyotype, nuclear, chloroplast, and mitochondrial DNA sequences of triticale cell cultures and regenerant plants are analyzed.