Doklady Biological Sciences最新文献

Cold exposure, especially in combination with exercise, is a common procedure to fortify the body. However, its effects in old age are poorly understood. Using the homeostasis stability coefficient as an indicator, the body response to a 20-min swim in cold water was for the first time studied comprehensively in old and young Wistar rats. Effects on the hormonal, hematological, and morphofunctional systems of the liver and thymus were assessed. Unfavorable age-related changes in the stability of homeostasis were observed in old rats. The changes complicated the recovery after cold stress and required the involvement of a greater number of homeostatic mechanisms than in young rats. The liver was found to be the most vulnerable to cold stress. It was concluded that fortifying the body by cold exposure is possible to use in old age, but with due regard to age-related restrictions.

Phytochemical characteristics and antimicrobial properties of extracts were studied in Nonea rossica Steven (Boraginaceae), which is widespread in Russia. The aerial part (herb) of N. rossica was harvested from a steppe meadow in the Novosibirsk region during flowering. The qualitative composition of biologically active compounds (BACs) was determined by thin-layer chromatography. Quantitative assays were carried out by spectrophotometry; flavonoids, hydroxycinnamic acids, and coumarin-like compounds were measured with reference to rutin, caffeic acid, and coumarin, respectively. Antimicrobial activity was determined by the serial dilution method. Gram-positive bacterial (Staphylococcus aureus ATCC 6538 FDA 209P and Bacillus cereus ATCC 10702) and fungal (Candida albicans NCTC 885-653) strains were used as test cultures. Phenolic BACs (hydroxycinnamic acids, flavonoids, and coumarins) were detected, and their quantitative contents determined. The highest yield of phenolic BACs was achieved using 40-70% ethanol as an extractant. Antimicrobial activity against S. aureus and B. cereus and antifungal activity against C. albicans were detected in N. rossica herb extracts prepared using 40-70% ethanol. The extracts were tested for the contents of caffeic acid and coumarin. Synergistic interactions of these compounds determined the bactericidal and fungistatic properties of the extracts.

The composition and content of polyphenols in leaves was studied in Spiraea aquilegifolia Pall. plants from nine natural populations of the Republic of Buryatia (Western Transbaikalia) by high-performance liquid chromatography (HPLC). At least 24 compounds were detected in hydroethanolic extracts of S. aquilegifolia leaves by HPLC. Of these, three phenol carboxylic acids (chlorogenic, p-hydroxybenzoic, and p-coumaric acids) and six flavonols (hyperoside, isoquercitrin, avicularin, astragalin, quercetin, and kaempferol) were identified. Hyperoside (2.9-8.2 mg/g), avicularin (3.0-5.8 mg/g), and isoquercitrin (0.8-2.5 mg/g) were the main flavonols found in leaf hydroethanolic extracts. Plants from populations located at the northern distribution limit in Western Transbaikalia were found to have higher contents of phenol carboxylic acids (near the village Koma) and flavonols (near the village Klyuchi). Plants from populations located at the eastern limit (near the villages Kusoty and Zagan) showed the lowest concentration of the identified phenolic compounds. The contents of the identified free phenolic acids and flavonols were moderate or high in S. aquilegifolia leaves as compared to other Spiraea species examined, rendering it important to further study the composition of phenolic compounds in S. aquilegifolia.

Conformational changes in DNA and protein biomolecules were studied in ischemic stroke (IS) cases varying severity by Raman spectroscopy. The conformational structure of hematoporphyrin was found to change in IS patients, leading to a higher (I₁₃₅₅/I₁₅₅₀)/(I₁₃₇₅/I₁₅₈₀) ratio (hemoglobin affinity of for ligands) and an increase in I₁₃₇₅/I₁₁₇₂ (a change in pyrrole conformation). Changes in genomic DNA spectra were observed at frequencies caused by stretching vibrations of primary amines (3400 cm^-1), secondary amines and hydroxyls involved in hydrogen bonding (3100 cm^-1), and CH₂ groups of sugar phosphates (2900 cm^-1) and vibrations of vibrational bonds between nitrogenous bases and sugars (1400 cm^-1). The significant changes observed in genomic DNA and hemoglobin spectra were assumed to indicate conformational rearrangements of the molecules in IS. Severe IS was associated with maximum changes in DNA and hemoglobin spectra.

Using high-performance liquid chromatography (HPLC), the contents of main classes of biologically active polyphenols in leaf extracts were analyzed in the medicinal species Spiraea chamaedryfolia L. (Rosaceae) and Lonicera caerulea subsp. altaica L. (Caprifoliaceae). Their features were studied in relation to the macroelement and trace element contents in soil and phytomass in sites with sporadic occurrence of serpentinites in the Altai Mountains. A total of 16 polyphenolic compounds were identified for the first time in S. chamaedryfolia leaf extracts. Of these, three compounds were attributed to phenol carboxylic acids; ten, to flavonols; two, to flavones; and one was identified as a flavanone. In L. caerulea subsp. altaica, the analysis confirmed the polyphenolic composition measured earlier, including hydroxycinnamic acids, flavonols, and flavones, and identified an additional compound as a flavanone. Species-specific shifts in plant secondary metabolism were found to occur in response to specific edaphic properties and the accumulation of macroelements and trace elements in leaves of plants growing in an area with a natural geochemical anomaly.

The article describes the first find of a bird from the Paleogene of Siberia. A fragment of tibiotarsus from the Eocene Tavda Formation of the Tyumen Region (Western Siberia) is assigned to Procellariiformes. The bird is morphologically closer to Procellariidae, but comparable in size to albatrosses (Diomedeidae) and is assumed to represent the stem members of the family. The find indicated for the first time that either stem albatrosses or similar large Procellariiformes could have had a worldwide distribution as early as the Eocene.

The LEPR gene encodes a leptin hormone receptor, and its mutations are associated with morbid obesity, dysregulation of lipid metabolism, and fertility defects in humans. Spontaneous Lepr mutations have been described in rodents, and Lepr knockout animals have been generated, in particular, using the CRISPR/Cas9 system. Lipid metabolism in rodents significantly differs from that in humans or rabbits, and rabbits are therefore considered as the most relevant model of morbid obesity and lipid metabolism dysregulation in humans. LEPR knockout rabbits have not been reported so far. In this work a LEPR knockout rabbit was generated by introducing a deletion of the region around LEPR exon 10 using the CRISPR/Cas9 system. The body weight of the knockout rabbit was significantly higher than the average body weight of the wild type rabbits. CRISPR/Cas9-mediated generation of LEPR knockout rabbits will allow the development of a model of morbid obesity and endocrine defects due to leptin receptor mutations in humans.

For the first time in Russia, the intraspecific structure of the brown rat Rattus norvegicus was studied using the mitochondrial control region (D-loop) as a molecular marker. The mtDNA sequence was determined in brown rats from eight regions of European and Asian Russia. Three rat clades were identified, including one in European Russia and two in Asian Russia. The synanthropic subspecies R. n. norvegicus was found to have two, European and Asian, lineages. The European lineage included haplotypes from central and southern regions of Russia, and the Asian lineage included haplotypes from Eastern Siberia and the Russian Far East. The exoanthropic subspecies R. n. caraco from the Russian Far East formed a separate genetic lineage.

The transcription factor Z4 (putzig) is one of the key proteins that determine the chromatin structure in Drosophila. Z4 is found at the boundaries of bands on polytene chromosomes, and the bands are currently thought to correlate with chromatin domains. Z4 is a component of a protein complex that additionally includes Chromator and BEAF-32, and a conserved domain is necessary to occur at the N end of Z4 to ensure its interaction with the two proteins. In this study, a zinc finger-associated domain (ZAD) domain was identified in Z4. The capability of dimerization was confirmed for the domain by biochemical methods. A dimer model of the domain was obtained using AlphaFold2, and the model structure was confirmed using small-angle X-ray scattering (SAXS). The dimer structure shows a fold typical of ZAD domains.

Logging in mature stands where part of the forest is harvested in one or several cuts and part is retained (clearcutting and alternate strip cutting) results in the formation of an ecotone complex (EC), which includes a forest (F) zone, a forest edge (FE) as a transition from the forest to the clear-cut under the canopy, a clear-cut edge (CE) as a transition from the forest to the clear-cut outside of the canopy, and the clear-cut proper (C). The composition and structure of ground vegetation and natural regeneration of woody species (Pinus sylvestris L., Picea abies (L.) H. Karst., Betula sp., Populus tremula L., Sorbus aucuparia L., and Juniperus communis L.) were studied in a bilberry pine forest-clear-cut ecotone complex 12-15 years after stand removal. Specific structural features of ground vegetation and undergrowth (including tree regeneration) were observed in each of the four zones of the ecotone complex formed after logging of the mature forest. A typical forest habitat (zone F) showed a minimum number of young regeneration of Pinus sylvestris, Picea abies, Betula sp., Populus tremula, and Sorbus aucuparia and the highest abundance of the lingonberry V. vitis-idaea L. and bilberry Vaccinium myrtillus L. with a maximum height and a maximum yield of bilberry plants. The amount of tree regeneration in the FE zone was much the same as in the F zone. The projective cover, maximum shoot height, and yield of bilberry and the maximum shoot height of lingonberry in the FE zone were significantly lower than in the F zone. The transitional zone on the clear-cut side (CE) and the clear-cut proper (C) strikingly differed from the forest (F and FE) zones of the ecotone complex by a greater number of deciduous and pine regeneration and a low abundance of dwarf shrubs. The clear-cut proper (C) differed from the CE zone by a higher abundance of grasses and forbs and an established tree regeneration layer composed of pine, birch, and aspen.