Vol 519, No 1 (2024)

The incomplete skull of Hapalodectes (Hapalodectidae, Mesonychia) is described from the Upper Paleocene Naran Member of the Naran Bulak Formation of the Khaychin-Ula 2 locality in the Bugin Tsav Basin in the south of Mongolia. This is the first discovery of the skull of a Paleocene member of the genus. The skull corresponds in size and dental occlusion to the species H. dux Lopatin, 2001, previously known only from a lower jaw from the Upper Paleocene Zhigden Member of the Naran Bulak Formation of the Tsagan-Khushu locality in the Nemegt Basin. In the structure of the facial part of the skull, H. dux exhibits features shared with Mesonychidae, namely the significant participation of the lacrimal and jugal in the preorbital region. The upper molars of H. dux were found to have distinct conules (a first for Hapalodectidae). The evolutionary changes in the structure of the upper molars of Hapalodectes (disappearance of the conules, decrease of the metacone, and narrowing of the lingual lobe) are determined. They were correlated with the transformations of the lower molars (reduction of the metaconid, protocristid, and entoconid, transverse compression of the trigonid and talonid) and together with them were aimed at enhancing the shearing action of the longitudinal blades of the posterior part of the dentitions.

A parasitological analysis was carried out on 29 samples of dog coprolites, soil and manure obtained from the cultural layer of the Mangazeya settlement (66°42'N, 82°16'E), which dates back to 1601–1670s (end of the late Holocene). For the first time in the north of Western Siberia, eggs of the nematode Dioctophyme renale (Goeze, 1782), which infects the kidneys of carnivores, were found in coprolites of dogs (Canis familiaris L., 1758). Currently, this species is not recorded in the helminth fauna of the region. The giant kidney worm could have entered the region with dogs brought by the Russian population from European Russia during the development of Siberia, however, the introduction of the helminth did not lead to the formation of a new stable natural focus of dioctophymiasis.

For the first time, it was shown that the development of resistance to antibiotics (amoxicillin and clarithromycin) in vitro in the probiotic strain Lactiplantibacillus plantarum 8p-a3, associated with large-scale genomic rearrangements, a change in the profile of phenotypic sensitivity to antimicrobials of different groups, and the evolution of virulence, is also accompanied by significant changes in the lactobacillus-derived extracellular membrane vesicles transferring lipids, polysaccharides, proteins, and nucleic acids. The changes are related to the structure and cargo of vesicles, as well as their activity against biofilms of opportunistic bacteria. The data obtained are relevant for understanding the molecular mechanisms of survival of microorganisms under the selective pressure of antimicrobials, the functional potential of the probiotic vesicles and assessing their safety.

The activity of key enzymes of energy and carbohydrate metabolism (cytochrome c oxidase (CO), lactate dehydrogenase (LDH), aldolase, glucose-6-phosphate dehydrogenase (G6PDH) and 1-glycerophosphate dehydrogenase (1-GPDH)) was studied in smolts of pink salmon Oncorhynchus gorbuscha (Walb.) from the White Sea in a cage experiment simulating its transition from freshwater to marine environment. A decrease in the activity of CO, G6PDH, 1-GPDH and an increase in LDH and aldolase in juveniles with increasing water salinity were revealed. The obtained results allow us to assume that in the studied pink salmon there is a redistribution of energy substrates between the reactions of aerobic and anaerobic metabolism towards an increase in anaerobic ATP synthesis. This may indicate the realization of adaptive mechanisms of metabolic restructuring in pink salmon juveniles, aimed at providing energy for the osmoregulation process when the salinity regime of the habitat changes.

The content of the main classes of storage lipids – triacylglycerols, cholesterol esters and waxes – in the muscles and liver of the beaked redfish (Sebastes mentella) and their changes in the depth gradient and in different areas of the North Atlantic were studied. Significant differences in the quantitative content of reserve lipids in beaked redfish’s from different fishing horizons were established. The analyzed changes the lipids in tissues and organs of fishes with increasing depth indicate the use of triacylglycerols, cholesterol esters and waxes as energy sources, as well as for maintaining buoyancy of the organism during vertical migration. The results of the study can be used for further study of the migration biochemical mechanisms of the commercial sea bass species of the North Atlantic – the beaked redfish, as well as other aquatic organisms with similar swimming activity. Reliable differences in the quantitative content of reserve lipids in sea bass from different fishing horizons were established.

The humoral immune system of Drosophila, the most studied among eukaryotes, is activated by the canonical IMD and Toll signaling pathways. Recently, new potential regulators of the innate immune response have been identified, such as long non-coding RNAs (lncRNAs) and genes encoding short polypeptides. S2 cells, being a macrophage-like cell line, are used as a model system to study the molecular mechanisms of immune response gene activation. We used this cell line to analyze the effect of Escherichia coli and Micrococcus luteus bacteria on the transcription of lncRNA-CR30055 and the CG45045 and CG44404 genes encoding short polypeptides. It was found that pathogens activate only CG45045, while the transcription levels of CR30055 and CG44404 remain unchanged. No activation of the Cecropin C gene and some Bomanin family genes was observed, indicating differences in the activation patterns of immune response genes in S2 cells and adult flies. The highest activation of CG45045 was observed between 6 and 12 hours of cell incubation with pathogens. The patterns of CG45045 activation after exposure to E. Coli and M. Luteus were similar, which may indicate common mechanisms of transcriptional activation of this gene. Thus, CG45045 may be a novel gene involved in the humoral immune response of Drosophila.

The phenotypic manifestations of increased expression of the Bap170 and e(y)3 (SAYP) genes in D. melanogaster were analyzed. Using the wing disc model, we show that moderate co-expression of Bap170 and e(y)3 genes in wing discs leads to abnormalities in wing veining. which was probably caused by suppression of EGFR/Ras/MAPK signaling pathways. Strong induction of co-expression of the above genes in wing discs leads to complete suppression of wing development in adults. Ubiquitous co-expression of Bap170 and e(y)3 is lethal at the 1st instar larval stage and leads to the formation of melanotic tumors. The above phenotypes are observed exclusively when Bap170 and e(y)3 are co-expressed. This evidence suggests a robust synergistic effect of the combined action of these genes, which is manifested in the hyperactivity of cell proliferation and differentiation.

Demyelinating diseases are a group of heterogeneous pathologies that affect the nervous system and reduce the quality of life. One such disease is multiple sclerosis (MS), an inflammatory autoimmune neurodegenerative disease of the central nervous system (CNS). At the initial stages, MS can mimic some infectious, neoplastic, genetic, metabolic, vascular and other pathologies. Accurate differential diagnosis of this disease is important to improve the quality of life of patients and reduce possible irreversible damage to the central nervous system. In this work, we confirmed the possibility of using our previously proposed candidate panel of MS biomarkers to distinguish MS from neuromyelitis optica spectrum diseases (NMOSD) and amyotrophic lateral sclerosis (ALS). We have shown that our proposed panel (SPTAN1_601-644 + PRX_451-494 + PTK6_301-344 + LMP1_285-330) allows us to distinguish MS from ALS (AUC = 0,796) and NMOSD (AUC = 0,779).