Vol 509, No 1 (2023)

Taxonomic diversity of the Late Cretaceous Hesperornithidae (Aves: Hesperornithidae) of the European part of Russia and Eastern Europe as a whole remain poorly understood, and the morphology of these large flightless birds is poorly known. New finds of Hesperornithidae in the Karyakino locality (Saratov oblast, Russia) confirm the coexistence of two forms of these flightless seabirds in the Campanian (mid-Late Cretaceous) of the Lower Volga region. For Hesperornis rossicus Nessov et Yarkov, 1993, a femur is described for the first time; it indicates a morphological distinctiveness of this large species as compared to the North American H. regalis Marsh, 1872.

The effect of modeling septoplasty and modeling sensory deprivation of the olfactory analyzer in rats on changes in the frequency domain of heart rate variability was compared. Bulbectomy provokes more pronounced changes in heart rate variability in rats, compared with septoplasty simulation.

In the estuaries of the largest Arctic rivers, namely, the Yenisei, Lena and Mackenzie, marine worms of the family Siboglinidae have been found. Their metabolism is provided by symbiotic chemoautotrophic bacteria. The strong salinity stratification characteristic of the estuaries of the largest Arctic rivers ensures high salinity at depths of 25–36 m, where siboglinids were found. High concentrations of methane necessary for the metabolism of siboglinids arise because of dissociation of permafrost gas hydrates under the influence of river runoff in the conditions of Arctic warming

The purpose of the article is to assess the biodiversity of gutless marine worms of the family Siboglinidae (Annelida), whose metabolism is provided by symbiotic bacteria that oxidize hydrogen sulfide and methane. Within the geographical boundaries of the Laptev Sea, 7 species of siboglinids were found, another 1 species was found in the adjacent sector of the Arctic basin. The largest number of finds and the greatest biological diversity of siboglinids were found in the eastern part of the Laptev Sea in the field of numerous methane. One find was noted in the estuary area of the Lena River at a depth of 25 m. The possible connection of siboglinids with methane seepage areas is discussed.

The northern three-toed jerboa Dipus sagitta was long considered to be a single polytypic species. Earlier, a high genetic diversity of D. sagitta was revealed on the basis of several mitochondrial and nuclear genes, and the existence of several separate species within it was hypothesized. However, a small number of available nuclear genes prevented the establishment of relationships between identified phylogenetic lineages. Here, we significantly expand the set of utilized nuclear DNA loci, which resulted in a sufficiently higher resolution of the phylogenetic tree for 10 forms of D. sagitta. The identified species structure mainly confirms the topology and relationship of the mtDNA lineages. At the same time, the mitochondrial and nuclear phylogenies are not completely consistent. Hence, a part of the genetic lineages of D. sagitta is apparently a product of reticular evolutionary processes. This taxon is thus the diverse species complex D. sagitta sensu lato, in which long-diverged lineages are not always reproductively isolated.

The TREX-2 complex integrates several stages of gene expression, such as transcriptional activation and mRNA export. In D. melanogaster TREX-2 consists of four main proteins: Xmas-2, ENY2, PCID2, and Sem1p. Xmas-2 protein is the core subunit of the complex with which other TREX-2 subunits interact. Xmas-2 homologues have been found in all higher eukaryotes. Previously, it was shown that the human Xmas-2 homologue, GANP protein can undergo cleavage into two parts, probably during apoptotic cell death. We showed that the Xmas-2 protein of D. melanogaster also can split into two fragments. The resulting fragments of the protein correspond to the two large domains of Xmas-2. Protein splitting is observed both in vivo and in vitro. However, Xmas-2 cleavage in D. melanogaster is observed under normal conditions and is probably a part of the mechanism of transcription and mRNA export regulation in D. melanogaster.

The Drosophila transcription factor СР190 is one of the key proteins that determine the activity of housekeeping gene promoters and insulators. CP190 has an N-terminal BTB domain that allows for dimerization. Many of known Drosophila architectural proteins interact with the hydrophobic peptide-binding groove in the BTB domain, which is supposed to be one of the mechanisms for recruiting CP190 to regulatory elements. To study the role of the BTB domain in the interaction with architectural proteins, we obtained transgenic flies expressing CP190 variants with mutations in the peptide-binding groove, which disrupts their interaction with architectural proteins. As a result of the studies, it was found that mutations in the BTB domain do not affect binding of the CP190 protein to polytene chromosomes. Thus, our studies confirm the previously obtained data that CP190 is recruited to regulatory elements by several transcription factors interacting in addition to BTB with other CP190 domains.

The effect of the phytohormone – methyl jasmonate (MJ) on the expression of the TaGS1 and TaPCS1 genes encoding glutathione synthetase and phytochelatin synthase, respectively, which are key enzymes in the synthesis of glutathione and phytochelatins in wheat (var. Moskovskaya 39), was studied. For the first time, it has been shown, that pretreatment of plants by exogenous MJ (1 μM) leads to an increase in the accumulation of transcripts of the TaGS1 and TaPCS1 genes in leaves without cadmium effect. When cadmium (CdSO₄, 100 μM) was added into the nutrient solution, the transcript level of TaGS1 gene increased in plants pretreated by MJ (compared to untreated plants), while the transcript level of TaPCS1 remained unaffected. The pretreatment of plants by MJ leads to a lower accumulation of cadmium in the roots and leaves of wheat. At the same time, MJ had no effect on the linear growth parameters of plants, but had a positive effect on the accumulation of biomass under cadmium. It has been suggested that MJ is involved in plant tolerance to cadmium by increasing the expression of the TaGS1 and TaPCS1 genes and, as a result, enhancing the synthesis of chelating compounds, as well as by reducing the supply of metal ions to plants.

The COVID-19 pandemic has shown the urgent need for new treatments for coronavirus infections. Nucleoside analogs have been successfully used to inhibit replication of some viruses, through the incorporation into the growing DNA or RNA chain. However, the replicative machinery of coronaviruses contains nsp14, a a non-structural protein with a 3'→5'-exonuclease activity that removes misincorporated and modified nucleotides from the 3' end of the growing RNA chain. Here we studied the efficiency of hydrolysis of RNA containing various modifications in the 3'-terminal region by SARS-CoV-2 nsp14 exonuclease and its complex with the auxiliary protein nsp10. Single-stranded RNA was a preferable substrate compared to double-stranded, consistent with the model of transfer of the substrate strand to the exonuclease active site proposed on the basis of structural analysis. Modifications of the phosphodiester bond between the penultimate and last nucleotides had the greatest effect on nsp14 activity.

A comparative analysis of natural antibodies to β-endorphin, angiotensin, dopamine, serotonin, parameters of the cardiovascular system and anxiety levels was carried out for 241 athletes of various qualifications and sports. The obtained indicators of the cardiovascular system were compared with reference values. A significant increase in the level of natural antibodies to angiotensin was established for all groups of athletes. In the case of dopamine, serotonin, these differences are associated with the qualification of the athlete, for β-endorphin, differences in the level of the indicator depending on the sport were found. A group of individuals with high levels of situational and personal anxiety was found among highly qualified athletes. An increase in blood pressure in athletes of cyclic sports and martial arts is adaptive, and in athletes of speed-strength sports it leads to a change in the walls of the myocardium. As a result of the study, the possibility of a comprehensive determination of natural antibodies and functional indicators as diagnostic markers for assessing the state of the human cardiovascular system has been shown.