Vol 15, No 4 (2017)

Background. Rhizobial Nod factors (NFs), the key regulators of legume-rhizobia symbiosis, act in low concentrations and their biological activity depends on structural features, that suggests the presence of specific receptors in plants. Putative receptors, LysM-receptor-like kinases (LysM-RLKs), were found in model legumes L. japonicus and M. truncatula. However, binding capacity with NFs was only studied for L. japonicus LysM-RLKs. In pea a few candidates for NF receptors like Sym10, Sym37 and K1 were found. Analysis of mutants revealed the importance of these proteins for symbiosis development. However, the biochemical function of these receptors has not been studied.

Materials and methods. Sequences encoding extracellular domains (ECDs) of LysM-RLKs Sym10, Sym37, and K1 were cloned in the pRSETa vector. Constructs were introduced in E. coli strain C41 to produce proteins with His6 residues on either the amino or carboxyl terminus. Protein purification was carried out using metal chelate affinity chromatography. The binding capacity with ligand was evaluated using ProteonXPR36 biosensor.

Results. To study binding capacity with NFs, we have developed approaches for the synthesis of LysM-RLK Sym10, Sym37 and K1 in soluble form in heterologous system. The high level of protein synthesis was achieved at +28 °C using 0,5 mM IPTG in 2-16 hours. Analysis of binding capacity of ECDs with NFs revealed the low affinity using the surface plasmon resonance.

Conclusion. The possibility of recombinant receptor synthesis in soluble state in E. coli at high level was demonstrated. Analysis of binding capacity with NFs showed the potential interaction, but with low affinity.

Background. Exome polymorphism is a rich source of information on the structure and function of proteins and metabolic pathways. The traditional diet of native populations of Northeast Asia (Eskimos, Chukchi and Koryaks) is enriched with fatty acids, which presupposes the existence of adaptive rearrangements of the lipid metabolism system among northern aborigines. Carnitine acyltransferases are the most important group of enzymes that metabolize fatty acids.

Materials and methods. To study adaptive changes in the genes encoding for the carnitine acyltransferases, we performed a screening of polymorphisms in the exons of CPT1A, CPT1B, CPT1C, CPT2, CRAT, and CROT genes in various populations of native inhabitants of Siberia.

Results. In exons of five genes (with the exception of CROT), 16 non-synonymous substitutions were identified. Of these, three substitutions were detected at high frequencies in populations of Northeast Asia (in Eskimos, Chukchi and Koryaks): at the loci rs80356779 of the CPT1A gene (replacement of P479L) and rs763273578 of the CPT1C gene (T740A), as well as a new polymorphism at position 131866581 of chromosome 9 at the CRAT gene (S99F). Exome analysis showed that among native populations of Northeast Asia, new non-synonymous substitutions with high pathogenicity indices appeared in the genes of energy metabolism and lipid exchange (genes GK2, ABHD6, NCOA2, OSPL3, LRP10, TTN, and PTTG2).

Conclusion. It is assumed that new variants of non-synonymous polymorphism arose as a result of genetic adaptation of native peoples to the extremely cold climate and a specific “Arctic” diet of aborigines of the Far North.

Background. Maintaining radon safety is one of the most critical challenges in modern ecology and genetic toxicology. Radon (²²²Rn) and its decay daughter products (²¹⁸Po, ²¹⁴Po, ²¹⁴Pb and ²¹⁴Bi) can interact with biological tissues and induce DNA damage. Because transcribed copies rDNA are necessary for DNA damage repair, we examined whether genomic dosages of active ribosomal genes modulate the genotoxic effects of exposure to high doses of radon.

Materials and methods. Chromosome aberration assay in peripheral blood lymphocytes was performed in pupils of the boarding school of Tashtagol (Kemerovo region, Russia) with long-term resident exposure to radon (n = 345) and in childrenof the Kemerovo Region living in radiation-safe conditions (n = 233). The dose of active (transcription-capable) ribosomal gene (AcRG) in the studied groups has been analyzed using Ag-NOR_S staining regions of chromosomes and cytogenetic semi-quantitative evaluation method.

Results. A statistically significant increase in the level of chromosome aberrations in exposure group has been revealed compared with the children of the Kemerovo Region living in radiation-safe conditions (p = 0.00001). It was found that the level of chromosomal abnormalities in Tashtagol’s children was higher in medium-dose carriers of AcRG compared to owners of a low dose (4.27 ± 0.22% vs. 3.24 ± 0.29%, p = 0.003). Perhaps the low level of chromosomal aberrations in children with low-dose AcRG is associated with an increase in cell death from damaged DNA under genotoxic exposure to radon.

Conclusion. The obtained results testify to the significant contribution of the individual characteristics of ribosomal genes in the formation of genotoxic effects of exposure to high doses of radon.

At least 30 subspecies of the honeybee Apis mellifera L. were formed allopatrically during the evolution, which spreaded throughout all Africa, Europe and West Asia. The dark forest bee Apis mellifera mellifera is the only and most valuable subspecies for the Northern and Western Europe countries, adapted to productive living in the hard-continental climate of Eurasia. In the past 100 years, natural geographical isolation of subspecies has been disrupted as a result of a human activities. Mass transportations of honeybee colonies beyond the boundaries of their area have been threatened of loss the identity of gene pool of subspecies as a result of hybridization. Preservation of the gene pool of subspecies is possible only when controlling the transportation of honeybee colonies using the methods of identification of taxonomic affiliation of honeybee colonies. Now, dozens of methods have been developed to identify the taxonomic affiliation of honeybee's colony, which are based on the variability of body parts, allozyme loci, mitochondrial DNA loci, microsatellite nuclear loci, sites of single nucleotide polymorphism (SNP). The variability of microsatellite loci and the single nucleotide polymorphism sites have shown the greatest informativeness in identification of the taxonomic affiliation of honeybee's colony.

The aim of the work was an investigation of the effect of hydrocarbons on bacterial and fungal cenoses of sod-podzolic soils on the territory adjacent to the oil storage in the village Malye Kolpany, Leningrad Region. NGS methods were used to analyze the taxonomic composition and structure of the bacteriocenosis and the method of direct microscopy by Demkina-Mirchink to determine the length of the fungal mycelium and the number of spores. Taxonomic and structural changes in the bacterial community led to the dominance of genera containing numerous species-oil destructors. It is established that the main role in the decomposition of oil in the investigated territorybelongs to prokaryotes related to the genera Pseudoxanthomonas, Methylobacterium and Nocardioides. Mycocenosis showed high sensitivity and low adaptability to oil contamination.