Vol 18, No 3 (2020)

Basic innate immunity in plants is achieved via interactions between highly conserved pathogen-associated molecular structures and plant pattern recognition receptors, leading to elicitation of signaling cascades triggering molecular and cell defense mechanisms. At present, most of the components of basic innate immunity in barley have not been identified yet. Here, an overview of current knowledge on mechanisms underlying innate immunity in cereals is presented, based mostly on the data obtained for representatives of Triticeae and Oryzaeae, with a focus on the relationship between immunity, induction of autophagy and elicitation of programmed cell death during the defense response in barley.

Annexins belong to the superfamily of calcium-dependent phospholipid binding proteins. The participation of these proteins in the regulation of structural organization of membranes, vesicular transport and a variety of signal transduction pathways is important for many cellular processes. Despite the structural similarity with animal annexins, plant annexins are characterized by significant variability of the N-terminal region and modification of calcium-binding motifs in II and III repeats, while calcium-binding motifs in I and IV repetitions remain conservative. However, the physiological role of animal and plant annexins, as well as mechanisms of their influence on calcium metabolism, may be similar. This review focused on the latest data about the structure and functioning of plant annexins.

Background. Rats’ natural ability to swim and dive provides adaptation in the wildlife and is widely applied as an instrument in experimental physiology. Nevertheless there’s little scientific evidence on diving behaviour in rats itself. Meanwhile this behavioural pattern might be a notable trait to shed light on functional features of the nervous system, the higher nervous activity structure and evolutional adaptability in animals, including inherited ones.

Materials and methods. In the present work we compared the performance of the spontaneous diving behaviour in the Morris water maze and forced diving behaviour in the “Extrapolation escape task” in two selected rat strains genetically differing in the nervous system excitability threshold.

Results. We found a greater extent and adaptive pattern of both types of the diving behaviour in the high-excitable LT strain. This may be due to such basic features of this strain as high exploratory activity and an increased level of fear reactions. It was also shown that the second, low-excitable HT rat strain, demonstrates maladaptive jumping behaviour in the “Extrapolation escape task” due to higher anxiety level in the stress conditions.

Conclusion. Observed differences between two strains allow us to consider the diving behaviour performed by high-excitable rats an inherited strain characteristic resembling adaptive rat behaviours in the wild and look forward to investigate its genetic mechanisms.

Background. Spoil heaps chronosequences are convenient models to analyze the succession of microbiome during restoration of anthropogenically disturbed landscapes. The investigation of the heavy metal content in lands with mining activity, can be used as an indicator of ecosystem recovery.

Materials and methods. Objects were technozems of 1-year, 25- and 50-year-old embryonic soils, and control soil under forest. Quantitative polymerase chain reaction (qPCR) and NGS-sequencing of V4 region of 16S rRNA gene were applied. Results. During the soil-forming process, an increase organic carbon and nitrogen, as well as a gradual increase archaeal 16S rRNA gene copies and in the number of Bradyrhizobiaceae, Blastocatellaceae, Xantobacteriaceae. Although we found a number of taxa that increased during soil-forming process (Thaumarchaeota, Bradyrhizobiaceae, Blastocatellaceae, Xantobacteriaceae), technozems of different ages had a similar structure and diversity of prokaryotic communities, differing from a nature soil. Biodiversity analysis revealed that technozems generally had a similar structure and diversity of prokaryotic communities, significantly differing from the mature soil a specific clusterization of microbiomes. The HM contents and bacterial abundances remained at the same level in chronosequence.

Conclusions. The 50 years of soil development on overburden spoil heaps is not enough for the recovery from HM contamination and restoration of soil ecosystem functioning.

Background. The alpha-test allows to detect inherited genetic changes of different types, as well as phenotypic expression of primary DNA lesions before the lesions are fixed by repair. Here we investigate ability of the alpha-test to detect base modifications induced by 6-N-hydroxylaminopurine (HAP) and determine frequency of inherited and non-inherited genetic changes in yeast strains treated with HAP.

Materials and methods. The alpha-test is based on mating type regulation and detects cell type switch from α to a in heterothallic yeast Saccharomyces cerevisiae. The frequency of mating type switching reflects level of both spontaneous and induced by a mutagen DNA instability. The alpha-test may be performed in two variants: “illegitimate” hybridization and cytoduction. Conducting both complementary tests and analysis of phenotypes of the “illegitimate” hybrids and cytoductants allows to detect the full spectrum of genetic events that lead to mating type switching, such as chromosome III loss and chromosome III arm loss, mutations and temporary lesions, recombination and conversion.

Results. HAP increases the frequency of illegitimate hybridization by 5-fold, and illegitimate cytoduction by 10-fold. A large proportion of the primary lesions induced by HAP causes temporary mating type switch and the remainder parts are converted into inherited point mutations.

Conclusion. The alpha-test can detect HAP-induced base modifications and may be used to investigate the ratio between correct and error-prone processing of such primary DNA lesions. Like other genetic toxicology tests the alpha-test has limitations, which are discussed.

Background. Active ribosomal genes and DNA repair genes play an important role in restoring genome integrity. Therefore we were studied relationship of active ribosomal genes dose and DNA repair genes polymorphisms with high level of chromosomal disorders in miners.

Materials and methods. The DNA damage level was assessed using chromosomal aberrations (CA) at 288 coal miners and 676 men in the control group. The dose of active ribosomal gene (AcRG) has been analyzed using Ag-NORS staining regions of chromosomes and cytogenetic semi-quantitative evaluation method. Real-time PCR and allele-specific PCR techniques were used to analyze polymorphic variants of the XPG (rs17655), XPD (rs13181), XRCC2 (rs3218536), and XRCC3 (rs861539) genes.

Results. A statistically significant (p = 0.0001) increase of the СА level at miners was found in comparison with the control group. The association XPD 2251T>G locus with increasing CA level is revealed of in recessive inheritance model (p_adj = 0.0001). The association XPG 3310G>C locus with increasing СА level is revealed at the smoking workers (p_adj = 0.017). An average dose of AcRG was registered a statistically significant increase in the frequency of single fragments (p = 0.016) at the miners.

Conclusion. The obtained data on associations of chromosomal aberrations with different variants of DNA repair genes and the dose of active ribosomal genes are useful for the formation of high-risk groups.