Vol 514, No 1 (2024)

On the example of 14 lake-type water bodies distributed over different latitudes of the northern hemisphere, it was shown that the efficiency of phytoplankton production transformation through heterotrophic bacterioplankton and non-predatory zooplankton to predatory zooplankton and planktivorous fish increases in the direction from eutrophic to oligotrophic water bodies. The highest ratios between autotrophic and heterotrophic organism production were found for lakes and reservoirs, where the contribution of allochthonous substances to the total energy flow is relatively high. Bacterioplankton utilizing allochthonous DOM is an additional source of energy for zooplankton, which, in turn, serves as a food object for planktivorous fish. Therefore, to predict the total biological productivity and production of the fish community, it is necessary to take into account the production of not only autotrophic plankton, but also that part of heterotrophic bacterioplankton that specializes in the utilization of DOM entering the water body from outside.

In 5 species of cestode plerocercoids parasitizing fish, free endings of peripheral neurosecretory neurons were found in the tegument in the ultrastructural study. These free terminals secreted vesicles on the tegument surface and into the host body. An increase in secretion under the influence of the blood serum of a fish host has been experimentally shown. In the body of cestodes, neurosecretory neurons (NN) form paracrine-type contacts near the cell membranes of the frontal glands, tegument, and muscles, performing the function of endocrine glands. Simultaneously, NN function as exocrine glands and secrete so-called manipulative factors that influence the physiology of the host.

An analysis of data on the content of 13C and 15N isotopes in the collagen of the bones of the small cave bear (Ursus (S.) rossicus Borissak, 1930) from localities in the Middle and Southern Urals was carried out. The bones date from the Interglacial (MIS 5) and Glacial (MIS 3) periods. The bones of males and females aged 3 years, 4 years and older than 4 years were studied. Sexual, geographical and chronological differences in the content of 13C and 15N isotopes were studied. Notable gender, geographic, and chronological differences between samples are shown. In the Middle Urals, during the interglacial period, females led a more predatory lifestyle than males, and during the transition to the glacial period, the trophic niches of males and females converged due to an increase in herbivory. During the interglacial period in the Southern Urals, males led a more predatory lifestyle than in the Middle Urals. In the Southern Urals, during this transition, the scale of changes in δ13C and δ15N values corresponds to the scale of differences between trophic levels.

Myosin 1C is a monomeric myosin motor with a truncated tail domain. Such motors are referred as slow “tension sensors”. Three isoforms of myosin 1C differ in short N-termed amino acid sequences, the functional differences between isoforms have not been elucidated. Myosin 1C isoform A has been described as a diagnostic marker for prostate cancer, but its role in tumor transformation remains unknown. Based on data on the functions of myosin 1C, we hypothesized the potential role of myosin 1C isoforms in maintaining the tumor phenotype of prostate cancer cells. In our work, we showed that a decrease in the expression level of myosin 1C isoform C leads to an increase in the proliferative activity of prostate tumor cells.

According to the World Health Organization, as of September 13, 2023, there have been approximately 23 million confirmed cases of COVID-19 reported in the Russian Federation, about 400 thousand of which were fatal. Considering the high rate of mutation of the RNA-containing virus genome, which inevitably leads to the emergence of new infectious strains (Eris and Pyrola), the search for medicinal antiviral agents remains an urgent task. Moreover, taking into account the actively mutating receptor-binding domain, this task requires fundamentally new solutions.

This study proposes a candidate immunoliposomal drug that targets the S protein of SARS-CoV-2 by the monoclonal neutralizing antibody P4A1 and ensures the penetration of a highly active ribonuclease into the virus-infected cell, which degrades, among cellular RNA, viral RNA too. We demonstrate a more than 40-fold increase in the neutralizing activity of the developed drug compared to the free monoclonal neutralizing antibody.

The search for new cytotoxic agents capable of lysing tumor cells is an important task in the fight against cancer. Here we have shown that the protein HspBP1, the chaperone of the heat shock protein Hsp70, is able to form a complex with the previously discovered peptide (17.1) of the innate immunity protein Tag7. Experiments using thermophoresis have demonstrated that the affinity of the Tag7 protein peptide 17.1 to the HspBP1 molecule is 100 times higher than that of the full-sized Tag7 molecule. The addition of the 17.1-HspBP1 complex to tumor cells induces apoptosis and necroptosis in them. The results obtained in this work can be used to develop promising antitumor drugs.

A new in vitro model of Huntington's disease (HD) has been developed, based on the direct reprogramming of dermal fibroblasts from patients with the disease into striatal neurons. Direct reprogramming makes it possible to obtain neurons, preserving the epigenetic information inherent in the cells of a specific donor, and, consequently, the age-associated phenotype of the disease. The new model resembles the main histopathological feature of Huntington's disease – the accumulation of aggregates of the mutant huntingtin protein in striatal neurons obtained from the patient's fibroblasts. Conducting experiments on induced neurons from patients in culture, obtained using direct reprogramming, allows us to individually assess the degree of progression of neuropathology and implement a personalized approach in choosing a treatment strategy and selecting drugs for therapy. The in vitro model of Huntington's disease can be used for preclinical drug studies, for the treatment of neurodegenerative diseases and for assessing their effectiveness on neurons of specific patients.

Buttonquails (family Turnicidae of the order Charadriiformes) are a morphologically specialized group of small, predominantly tropical birds of open landscapes, extremely poorly represented in the fossil record. The article describes a fragmentary humerus of a buttonquail from the Lower Pleistocene of the Taurida Cave in central Crimea. This is the first find of the family Turnicidae in Eurasia in the chronological interval from the Pliocene through the Middle Pleistocene. This find highlights the limited available information on the taxonomic composition of Early Quaternary Eurasian avifaunas, even at the family level, and also sheds light on the Late Cenozoic evolutionary history of Turnicidae.

An analysis of data on the content of 13C and 15N isotopes in the collagen of the bones of the small cave bear (Ursus (S.) rossicus Borissiak, 1930) from three regions of Western Siberia was carried out. The bones are dated to Marine Isotope Stage (MIS) 3. The bones of mature males and females were studied. Differences between some samples appear only in the δ15N values. Bears from all samples belong to the same trophic level. Trophic shifts have been established between females and males in one area and between males in two areas. The small cave bear of Western Siberia differed from the small cave bear of the Southern Urals in a much more predatory way of life. The level of differences between the bears of the Urals and Siberia corresponds to different trophic levels.

In mammals, the main contribution to the variability of pigmentation is made by two groups of genes directly related to the metabolic pathways of pigment synthesis and controlling the transport of melanosomes in melanocytes to keratinocytes. In order to identify the genetic basis of pigmentation variants, the nucleotide sequences of the melanophilin gene were compared in two groups of ferrets – silver-colored and wild-type animals using sequencing of 16 exons. In carriers of silver color, a single nucleotide deletion was detected in the 9th exon, leading to a shift in the reading frame and the formation of a stop codon downstream. The protein encoded by the mutant allele is almost completely devoid of the C terminal domain of the protein responsible for the contact of melanosomes with actin during their muving to the periphery of melanocytes, but it retains the leading domain involved in the formation of melanosomes. The combination of the preservation of the N domain and the defect of the C domain of the mutant protein for the first time makes it possible to explain the incomplete dominance of the wild-type protein in heterozygotes.

PHF10 is a subunit of the PBAF complex, which regulates the expression of many genes in developing and maturing organisms. PHF10 has four isoforms that differ in domain structure. The PHF10A isoform, containing a DPF domain at the C-terminus and 46 amino acids at the N-terminus, is necessary for the expression of gene proliferation; the functions of the other isoforms are less studied. In this work, we have established that upon contact inhibition of mouse and human cell proliferation caused by the establishment of a tight junction and adherence junction between cells, the expression of the PHF10A isoform stops and instead the PHF10D isoform is expressed, which does not contain DPF-domain and N-terminal sequence. The function of the PHF10D isoform may be associated with the establishment of intercellular contacts.