Vol 513, No 1 (2023)

The dentary of Mustela strandi Kormos, 1934 is described from the Lower Pleistocene deposits (Late Villafranchian, 1.8–1.5 Ma) of the Taurida cave in Crimea. It is the first finding of M. strandi in Russia. This extinct mustelid species is rarely found in the Lower and Middle Pleistocene of Central Europe.

Data on the content of δ¹³C and δ¹⁵N isotopes in the collagen of bones of the Ural cave bear (Ursus (S.) kanivetz Verestchagin, 1973) from the Northern and Middle Urals were analyzed. The bones date from the first half of MIS 3. The bones of newborn individuals, individuals at the age of 1 year, males and females at the age of 2 years, 3 years, 4 years and older than 4 years were studied. Differences in δ13С values between age, sex, and geographical samples are not significant. With age, the value of δ15N significantly decreases, which is associated with the transition from milk nutrition to independent nutrition. The proportion of meat food in the diet of adult bears in the Middle Urals was higher than in the diet of adult bears in the Northern Urals. There are no noticeable differences in isotope signatures between males and females of different ages. The large cave bears of the Urals and Europe had a similar type of diet.

In the framework of this study, an experiment was carried out on the introduction of constant artificial lighting (24LD) into the standard technology for growing salmon juveniles under conditions of the southern region (Republic of North Ossetia-Alania) and its effect on the composition of fatty acids (FA) of total lipids in muscles and liver parr and smolts of the Atlantic salmon Salmo salar L. It has been established that the FA spectrum of fish is characterized by a change in the key FA factors, indicating the full completion of smoltification and the readiness of smolts for new habitat conditions: a significant increase in the content of polyene FAs (PUFAs) due to (n–3)PUFA, and in them FA of the “marine” type – 22:6(n–3), high values of the ratios (n–3)/(n–6)PUFA, 22:6(n–3)/18:3(n–3).The most significant changes were noticed in the muscles, and for all experimental groups it was found that a decrease in saturated fatty acids (SFA) and an increase in total lipid unsaturation occurs primarily due to PUFAs, while monoene FAs decrease along with SFAs. The data of experimental studies of the lipid and fatty acid composition of salmon youngs, as well as a higher proportion of smolts in the studied groups of fish, indicate that the most successful process of smoltification restructuring occurred in groups with constant lighting and 24 hours feeding and a natural regime of lighting and feeding.

For the first time, using GPS-GSM trackers, long-term seasonal flights of greater noctule bat (Nyctalus lasiopterus) from summer habitats in Russia to wintering areas in Europe have been recorded. One of the seasonal migratory flights is a record distance for bats (2515 km). The maximum daily flight was 445 km. One of the animals abruptly changed the direction of migration from southwest to north on the third day of flight after crossing the Kursk magnetic anomaly.

Previously, it was shown that the non-conventional toxin WTX from the venom of the cobra Naja kaouthia, when administered intravenously, caused a decrease in blood pressure (BP) and an increase in heart rate (HR) in rats (Ogay et al., 2005). To identify the site of the toxin molecule responsible for these effects, we studied the influence of synthetic peptide fragments of the WTX on BP and HR in normotensive male Sprague Dawley rats under general anesthesia induced by Telazol and Xylazine. It was found that peptides corresponding to the WTX central polypeptide loop, stabilized by a disulfide bond, at intravenous injection at concentrations from 0.1 to 1.0 mg/ml caused a dose-dependent decrease in BP, the HR increasing only in the first 5–10 minutes after administration. Thus, WTX fragments corresponding to the central polypeptide loop reproduce the decrease in blood pressure caused by the toxin.

Following the transcription step, the newly synthesized mRNA is exported from the nucleus to the cytoplasm and further to the translation site. The TREX-2 complex is involved in the step of mRNA export from the nucleus to the cytoplasm. This complex in Drosophila melanogaster consists of four proteins: Xmas-2, PCID2, ENY2, Sem1p. In our work, we have shown that deletion of the C-terminal sequence of PCID2 leads to a decrease in the interaction of the protein with RNA and to impaired mRNA export from the nucleus to the cytoplasm in D. melanogaster.

Forum-domains are 50–100-kb stretches of DNA delimited by the hot sport of DSBs. These domains possess coordinately expressed genes. However, molecular mechanisms of such regulation are not clear. It is supposed that the proteins specifically binding at the termini of domains could be involved in coordinated regulation of expression. In this study we used the results of precise mapping of hot spots of DSBs and ChIP-Seq data for ten nuclear proteins in HEK293T cell line for a search of proteins specifically binding at forum-domains termini. We detected that two proteins – CBP and RAD24-, which are known to be involved in epigenetic regulation of gene expression and formation of 3D chromosomal structures, bind at the termini. We suppose that these proteins could be involved in coordinated expression of genes in forum-domains.

The TREX-2 protein complex is the key complex involved in the export of mRNA from the nucleus to the cytoplasm through the nuclear pores. Previously, a joint protein complex of TREX-2 with ORC was isolated in D. melanogaster, it was shown that the interaction of TREX-2 with ORC is necessary for efficient mRNA export from the nucleus to the cytoplasm. In this work, we show that the TREX2-ORC joint complex is also formed in human cells.