Doklady Biological Sciences

The changes in the fatty acid composition of pink salmon smolts during the migration process (from start to finish) in the Indera River and as part of an experiment at the locations where cages were installed (river, estuary, White Sea), taking into account differences in water temperature and salinity were studied. Changes in the quantitative composition of fatty acids were found in pink salmon smolts in the middle of their downstream migration and in the experimental group of smolts kept in cages in the sea for 72 hours (higher content of total saturated and monounsaturated fatty acids and lower polyunsaturated fatty acids). The qualitative composition of the dominant fatty acids in pink salmon smolts is the same for all studied groups (16:0, 18:1(n-9) and 20:5(n-3) and 22:6(n-3)) and is similar to that at earlier stages of pink salmon development. In the framework of experimental works, variations in the content of 20:5(n-3) and 22:6(n-3) were established, which confirm the important role of these PUFAs in the processes of adaptation of pink salmon smolts to the transition from a freshwater river ecosystem to living in the sea.

The formation and maintenance of memory throughout life remains one of the central unsolved problems in neuroscience. Although many experimental models have been developed to study memory, there is currently a lack of paradigms that would allow for reliably investigating the mechanisms underlying highly stable memory over timescales comparable to the lifespan. In this study, we examined the ability of mice to form highly stable long-term memory using a contextual fear conditioning paradigm, an adapted model of post-traumatic stress disorder (PTSD) with varying intensities of aversive stimulation. We developed a one-trial learning model in which mice reliably formed long-term associative memories that persisted for at least six months, demonstrating a promising tool for investigating mechanisms of memory retention across the lifespan.

For the first time, an integrative analysis of the morphological, structural, and biochemical characteristics of buckwheat seeds of several varieties growing in contrasting conditions of the monsoon climate of Primorsky region and the temperate continental climate of the Central region of Russia has been carried out, which allows us to provide important practical recommendations for the application of a new seed assessment method. Minor differences in their color and weight indicators of varieties, as well as the weight and structure of fruit shells (FS) were revealed. In all varieties, the amount of total protein in the seeds (SD) was almost equal, and the protein composition differed only due to minor components. For SD, there were fairly similar indicators in terms of the total phenolic compounds (TPC), phenylpropanoids (PhP), flavans (FL) and proanthocyanidins (PA) content, which in most cases were lower than those for FS, with the exception of the new generation of the Desire variety. The significant accumulation of PA (polyphenol oligomers with high antioxidant activity) in buckwheat seeds, which we noted, can be used for their subsequent application in various sectors of the national economy.

This paper is devoted to the morphological features of the humerus and forearm of a Middle Pleistocene (Chibanian) camel, previously not found in Western Transbaikalia. Against the background of all previous finds in Central Asia, represented mainly by hand and foot bones, fossils from the Selenga middle mountains (Ust-Kiran locality, Chikoy River valley) provide a rare opportunity to most fully outline the morphosculpture of the long tubular bones of the forelimb. Their morphological features indicate that they belonged to the camel Camelus cf. knoblochi, and their sizes indicate that it was significantly larger than the Pliocene and modern forms. It occupied various biotopes in the middle mountains, where foothill trains directed towards river valleys and intermountain depressions were widespread.

The morphophysiological parameters of the oocytes of the Azov flounder were characterized during maturation and spawning in the Sea of Azov, as well as the analysis of the composition of fatty acids in the gonads based on samples from their three divisions in each studied fish: head (cranial), middle and caudal. The dynamics of morphophysiological characteristics and composition of fatty acids in flounder caviar during the spawning period has been established. It was found that physiologically significant oleic and docosahexaenoic fatty acids were dominant in the caviar of the studied fish species. At the same time, multidirectional trends in the content of these acids were established: the content of docosahexaenoic acid was higher in individuals at the beginning of spawning than in those at the peak of spawning, where oleic acid prevailed.

Syngenetic models are widely used in experimental oncology both for modeling tumor diseases and for testing anticancer drugs. However, when testing targeted drugs aimed at human tumor-associated antigens, the presence of target antigens in the animal's body is important. In this work, a syngenetic cell line with stable expression of two genes — ERBB2 gene encoding human epidermal growth factor type 2 HER2, and NaoLuc luciferase gene — was created based on human murine mammary gland carcinoma. Optical bioimaging methods have proven that the created cell line is characterized by stable expression of ERBB2 and NanoLuc in vitro and in vivo, retains the aggressiveness growth of the original 4T1 cell line in animals, and forms spontaneous metastases that are detected in the animal's body by intravital biovisualization methods.

DHX9 helicase and its ortholog MLE in D. melanogaster participate in different stages of gene expression. Both helicases are important for the formation and functioning of the nervous system in humans and D. melanogaster, respectively. However, the role of helicase activity of DHX9 and MLE in the regulation of gene expression has been poorly studied, and the existing data are quite contradictory. This work is devoted to the study of the role of helicase activity of MLE in the regulation of gene expression in D. melanogaster. On chromosome 4 of D. melanogaster, in locus 102F, a site of intense MLE binding was found. It was shown that MLE is a co-activator of expression of the Dyrk3, Toy, Sox102F, Shaven and Fuss genes located in this locus. For this, the helicase activity of MLE is required. Genes whose expression depends on MLE are expressed at a high level in the nervous system of D. melanogaster and are necessary for its proper development. The obtained data contribute to the study of potentially evolutionarily conserved functions of MLE.

The fatty acid (FA) composition of the mantle, foot (muscle) and hepatopancreas of the European pearl mussel Margaritifera margaritifera from the Kem River (estuary), the Ukhta River, and the Vozhma River (Republic of Karelia, Russia) was studied for the first time. All tissues of the pearl mussel from the studied rivers were found to have a higher content of saturated and polyunsaturated FAs compared to monounsaturated ones, which may be due to the post-spawning period. In the hepatopancreas of the pearl mussel was shown a predominance of polyunsaturated FAs due to the FAs of n-3 family, as well as a higher value of FA – 16:1(n-7), 18:1(n-7), 18:3(n-3), 20:5(n-3), 22:6(n-3) and a lower amount – 16:0, 18:0, 18:1(n-9), 20:1(n-11) and 20:4(n-6) FAs compared to the foot and mantle. An important distinctive feature of M. margaritifera is the high amount of 20:1(n-11) FA. Mollusks from the estuary of the river Kem were distinguished by a higher content of 18:0, 20:5(n-3) FA in all the studied tissues and a lower content of 18:1(n-7), 18:2(n-6), 22:6(n-3) FA. The obtained data are important for monitoring work to assess the state of pearl mussel populations in different rivers of the European North, including using physiological and biochemical indicators.