The epidermal growth factor (EGF) is a peptide of the EGF-like growth factor family with a common conserved EGF-like domain formed by three intramolecular disulfide bonds. This article describes changes in the spatial structure of EGF and its mutant form with the D46G substitution in its C-terminal fragment observed upon disulfide bonds reduction in the corresponding synthetic peptides in a 0.01 M phosphate buffer (pH = 7.4). The structure was analyzed using circular dichroism spectroscopy, spectrofluorimetry, native polyacrylamide gel electrophoresis, and centrifugal ultrafiltration. It was shown that disulfide bonds reduction changes the geometry of the EGF-like domain towards an increase in the content of the beta-structure, while these peptides remain in dimeric form. According to the molecular modeling results, this can lead to the elongation of the main beta-hairpin of the EGF-like domain, to the elongation of the intermolecular beta-structure, or to the formation of a new beta-structure between the N- and C-terminal fragments of each molecule, which will change the intermolecular interface in dimeric form. Disulfide bonds reduction prevents EGF dimer dissociation to monomers. Under physiological conditions, this can lead to the inability of EGF to form binding sites for EGFR (epidermal growth factor receptor) and to cause its activation.

The state of lipid peroxidation (LPO), respiration and oxidative phosphorylation, mitochondrial permeability transition pore (mPTP), and the antiradical activity of rat liver mitochondria in the streptozotocin (STZ)-induced diabetes condition were studied with the consideration of the ways of correcting detected membrane damages using gossitan isolated from the cotton plant Gossypium hirsutum L. It was shown that the rate of respiration of liver mitochondria in states V3 and V4 increases during STZ-induced diabetes, which significantly reduces the respiratory control (RC) and ADP/O coefficients in comparison with the control. The findings suggest that the uncoupling of respiration and oxidative phosphorylation takes place during STZ-induced diabetes. It was shown that in the STZ-induced diabetes condition, the rate of swelling of rat liver mitochondria is higher than that of the healthy ones; this means that mPTP of rat liver mitochondria is in the open state. Gossitan recovers mPTP to the normal condition, thereby removing the STZ effect on mitochondria. Gossitan (a personal dose is 10 mg/kg of body weight, during 8 days) eliminates the detected functional disorders of rat liver mitochondria, probably due to its antioxidant properties.

To solve the problem of delivering pharmacologically promising 3ʹ,5ʹ-cyclic diadenosine monophosphate (cyclo-diAMP) to target cells in humans and animals, the complexes of the above-mentioned dinucleotide with natural polymer – chitosan were originally synthesized by ionotropic gelation technique. It was found that the binding degree of cyclo-diAMP to this biopolymeric carrier reaches 60 %; wherein the capacity of the obtained complexes with respect to the dinucleotide is 800–860 µg/mg of the produced complex. Cyclo-diAMP has also been shown to elute from the chitosan complex to the citrate-phosphate buffer (pH 7.4) up to 36 % by 21 hours. The obtained results testify in favor of potential application of cyclodiAMP complex with chitosan for prolonged delivery of the studied cyclic dinucleotide to target cells.

Cultures of Bacillus amyloliquefaciens BIM B-1267 D, B. mojavensis BIM B-1268 D, Priestia megaterium BIM B-1269 D and B. amyloliquefaciens BIM B-1270 D bacteria, which form the basis of the bioproduct “Bioproductin”, have mutually complementary properties – pronounced antimicrobial, nitrogen-fixing, phosphate-mobilizing and phytostimulating activities, the ability to synthesize a number of hydrolytic enzymes (proteinase, endo-1.4-β-xylanase, endo-1.4-β-glucanase, α-amylase and phytase), indolylacetic acid, siderophores. In the genomes of the studied bacterial strains, the presence of genes encoding the synthesis of bacillen, bacillibactin, bacillomycin, difficidin, phengicin, macrolactin, surfactin, and iturin was established, which confirms their significant antimicrobial potential. It is also shown that the genes determining the synthesis of indolylacetic acid – the main hormone of plant growth – are present in the bacterial chromosome.

It was found that the synthesis of surfactants by R. pyridinivorans 5Ap bacteria can be increased by exposing them to a short temperature shock (55 °C for 20 minutes) after 24 hour cultivation in a minimal medium containing molasses (3 %) and hexadecane (2 %) (9 % increase in the emulsification index). Gene activation encoding global regulators of cell metabolism, including those performing a protective function under stress, was recorded in this cultivation mode. In particular, the mRNA amount determining the synthesis of the alternative transcription factor SigH increased 90.8 times and containing in the promoters its binding sites fmdB cochaperone – 59.3 times, hsp22.5 chaperone – 81.1 times, and the trxB gene encoding thioredoxin reductase – 73.1 times. In addition, it was shown that the transcriptional activation of groEL1, groEL2 and dnaJ genes determining the synthesis of heat shock proteins was 2.2, 2.6 and 4.4 times, respectively. The obtained results suggest that an increase in the alternative factor sigma H synthesis, which activates protective cellular metabolism, as well as structural, heat shock proteins under short temperature stress, leads to an increased production of surfactants, which can be used to optimize the synthesis of these secondary metabolites for biotechnological use.

It has been established that 20 species (including two species complexes) of freshwater gastropods from 7 families live in water bodies on the territory of the PSRER, in which 51 species of trematodes from 21 families with a predominance of species of the Echinostomatidae family (10 species) parasitize at the parthenitis stage. The maximum number of trematode species was registered in the mollusks Lithoglyphus naticoides and Planorbarius corneus – 8 species of parasites with an infestation of 11.0 and 28.4 %, respectively. In the exclusion zone of the Chernobyl NPP, the circulation of natural focal helminthiasis caused by parasitization of trematodes Opisthorchiidae (Metorchis bilis, Pseudamphistomum truncatum, Opisthorchis felineus) identified in the studied animal species was established. For the mollusk Bithynia leachii, a high degree of infection (43.1 %) with the trematode O. felineus was noted.

Field studies and a retrospective analysis of distribution and life cycle features of the glacial relict Mysis relicta (Loven) on Lake Yuzhny Volos on the southern border of distribution of the species on the European continent were carried out. The size-age structure, number and density of the mysida population did not change over a half-century period on Lake Yuzhny Volos. Life cycle features, which consist in the existence of parallel lines of alternating one-year and two-year generations, remain stable. The mysida production characteristics were determined. It is shown that the somatic production of two-year generation females at the level of the individual and the population is two times higher than that of one-year generation females. During the gestation of juveniles, the female consumes the body weight energy equivalent, which is equal to 2.13 cal·individual–1 for a one-year generation and 7.32 cal·individual–1 for a twoyear generation, 9.5·108 and 25.5·108 cal for all individuals of one-year and two-year generations. Egg production for life in the mysida population was 29.5·108 cal, which is comparable to the total somatic production. The exuvial production of mysids at the level of the individual and the population turned out to be ten times higher than the somatic one. The energy spent for respiration is 900 times higher than the somatic production values for one-year generation females and 1200 times for twoyear generation females. The coefficient K2 values appeared to be close for the both generations (0.032–0.034) and are represented by very low values compared to the freshwater macrozoobenthos of temperate latitudes.

The article discusses the research results of the radiological efficiency of the carbon ferrocin-containing ¹³⁷Cs sorbent produced at the Institute of Nature Management of the National Academy of Sciences of Belarus on cattle and small farm animals.

The experiment was held at the Branch of the “Agro-Vetka” JSC “Vetka Agroservice” farm located in the Vetka district, Gomel region, Belarus, and involved two groups of lactating cows, 5 heads each. The experiment group, unlike the control one, was given a sorbent at a rate of 40 g per head per day mixed in the diet. Milk samples of the cows of the experiment and control groups were taken on the 0, 5, 8, 11, 14, 17 and 20th day of the experiment. Starting from the 5th day and up to the 20th day of sorbent feeding, a 1.7 to 4.5 time decrease in the ¹³⁷Cs content in milk was observed.

The sorbent cost in the experiment group per 1 thousand Bq of the obtained difference (against the control group) in the 137Cs content in milk was 0.65 rubles. The ferrocin use for the same purpose can be approximately 5.2 times more expensive.

The adsorption efficiency of ¹³⁷Cs by domestic sorbents based on carbon and ferrocin on small farm animals was studied. The experiment lasted 30 days and involved 4 groups of the 3-month Pannon White male rabbits, including 1 control and 3 experiment groups, three rabbits per each group. The experiment groups were formed using a pair matching method. Ferrocin and carbon-modified sorbents were mixed into the composition of rabbit compound feed.

The 1st group received 0.2 g ferrocin per head at a rate of 100 mg per 1 kg of live weight. The 2nd and 3rd groups were given 2 and 4 g of carbon ferrocin-containing sorbent per head, respectively, at a rate of 1 and 2 g per 1 kg of live weight, respectively. The effect of the carbon and ferrocyanide (5 %)-modified sorbent at a dose of 2 and 4 grams per rabbit is by a factor of 1.4 and 2.6, respectively, more effective than the application of ferrocin alone. A dose of 4 grams of the carbon-modified sorbent is by a factor 1.8 more effective than that of 2 grams.

The costs associated with 1 thousand Bq difference in accumulation of ¹³⁷Cs in rabbit meat in the “carbon sorbent 2 g/head” and “carbon sorbent 4 g/head” groups is respectively 0.93 rubles, or 7.6 times, and 0.83 rubles, or 4.0 times, lower than those in the “ferrocyn” group.

A scheme for measuring the plastic features of the brown bullhead, including 28 morphometric characteristics, has been proposed. Based on the cluster analysis of morphometric characteristics, the size groups of species of a model water body were determined (Karpin village pond, Maloritsky district, Brest region).

The change in the exterior parameters of the brown bullhead during its ontogenesis has been shown for the first time. It is proposed to divide brown bullhead individuals into 3 size groups for analysis: A – young individuals not involved in reproduction (body length without a caudal fin up to 135.0 mm); B – mature individuals that have started breeding (sizes from 136.0 to 174.0 mm); C – adults, actively breeding individuals (sizes from 175.0 to 187.0 mm).