[Effect of ionizing radiation on microbiological safety and activity of antioxidant enzymes in minced meat].

A number of studies have shown the effectiveness of meat irradiation at doses of 2-6 kGy to extend its shelf life when stored in vacuum packaging. It is known that the radiation treatment of meat can lead to a decrease in the content of natural antioxidants. Furthermore, the intensity of oxidative processes is significantly higher in meat products with a high fat content (20% or more). At the same time, the optimal modes of minced meat irradiation, which make it possible to ensure safety for the population and to increase the shelf life, have not yet been established. The purpose of the research was to study the effect of various doses of ionizing radiation on the content of aerobic, facultative anaerobic microorganisms and radiolysis products, and the activity of antioxidant enzymes in chilled minced meat during storage. Material and methods. The object of the study was minced meat, consisting of beef and pork (1 : 1) with 20% mass fraction of fat. The experimental samples were irradiated on an electron accelerator UELR-10-15-S-60-1 with an electron energy of 5-10 MeV at doses of 2, 2.5 and 3 kGy. The control sample of minced meat was not subjected to radiation treatment. Determination of the total count of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM) (CFU/kg) in control and experimental samples was determined on days 0, 7, 15 and 22. Methods for evaluating antioxidant activity included spectrophotometric determining the content of active radiolysis products that react with 2-thiobarbituric acid (TBA-AP) according to the Brajet method, total antioxidant capacity (TAOC) and activity of antioxidant enzymes in minced meat: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx). Results. Radiation treatment of minced meat at a dose of 2.0 kGy provided a normalized level of QMAFAnM in chilled minced meat for 22 days. It has been established that the treatment of minced meat with ionizing radiation in doses of 2.0-3.0 kGy leads to a dose-dependent decrease in its TAOC and the activity of antioxidant enzymes (SOD, CAT, GPx), as well as to an increase in TBA-AP content (р<0,05). Conclusion. The dose of ionizing radiation of 2.0 kGy helps to maintain the microbiological safety of minced meat for 22 days in terms of QMAFAnM with minimal changes in TAOC values, SOD, CAT and GPx activity and TBA-AP content.

[Dihydroquercetin influence on clinical and biochemical blood parameters of pigs under conditions of stress load].

In modern society, distress has become a widespread condition that negatively affects the functioning of all systems of the human organism. The study of biological mechanisms and changes in the organism under the influence of stress, as well as methods of their leveling, are relevant in medicine, animal science and veterinary medicine. Pigs are an excellent biological model that is closest to humans. The aim of the research was to study the hematological and biochemical parameters of pigs out of and under stress, including against the background of daily consumption of the flavonoid dihydroquercetin (DHQ) with feed. Material and methods. The research was conducted in the experimental yard of the L.K. Ernst Federal Science Center for Animal Husbandry on 3 groups of pigs [F2 hybrid (large white×Landrace)×Duroc] with an initial body weight of 30-35 kg (n=27). Group 1K consisted of control animals not exposed to stress (n=9); group 2K - control animals subjected to simulated stress by the rearrangement of animals (n=9); group 3O - experimental animals subjected to simulated stress and fed throughout the entire experiment DHQ (32 mg per 1 kg of feed) (n=9). On days 0, 42, and 76, blood was collected from the animals and their hematological and biochemical parameters were studied using conventional methods. Results. The positive effect of using DHQ in pigs' nutrition on enhancing the oxidizing function of blood, metabolic intensity, and increasing the endurance of animals under stress conditions has been manifested in maintaining leukocyte level with a higher content of erythrocytes and hematocrit. In animals fed DHQ, alanine aminotransferase activity was lower than in animals not receiving DHQ. Stress led to a significant increase in lactate dehydrogenase activity in group 2K on the 46th day, which was not observed in animals treated with DHQ. Conclusion. Long-term intake DHQ (up to 72 days inclusive) against the background of stress contributed to the preservation of blood values at the control level (without stress), within the physiological norm.

[The distinctive characteristics of the nutrient composition of reindeer meat from the Vorkuta district determined by the conditions of the region of origin].

Reindeer meat is an important source of crucial nutrients (protein, fat, minerals) in nutrition of Arctic indigenous people. The authentic meat properties are formed under the influence of many factors, the main of which are the lifetime factors including the region of production and peculiarities of keeping. The regional peculiarities of the reindeer meat composition are quite poorly reflected in the reference books on the chemical composition of food products and in the scientific publications. The aim of the work was to evaluate nutritional value, the level of amino acids, fatty acids, minerals and trace elements of reindeer meat from the Vorkuta district. Material and methods. The objects of the research were the samples of reindeer meat (m. longissimus dorsi) from the Vorkuta district obtained from the highly productive semi-domesticated young reindeers of the Nenets breed. The samples were taken from free-ranging male animals at the age of 8-10 month. The amino acid composition was analyzed by the chromatographic method, the mass fraction of tryptophan by the spectrofluorometrically method, oxyproline by the spectrophotometric method. The content of minerals and trace elements was detected by the flame atomic absorption method. The lipid extraction from the average sample was carried out by the extraction with chloroform/ methanol by the Folch method, the purity of the extracted lipids was controlled by the method of thin layer chromatography. The fatty acid composition was determined the gas chromatographic method. Results and discussions. The indicators of the chemical composition of reindeer meat from the Vorkuta district were established. The content of protein was 23.0%, the content of fat 1.2%. The high content of tryptophan (0.628 g/100 g of the product) was characteristic for this prodact. The ratio of tryptophan to oxyproline was 11.8, which exceeded the values in pork and chicken. The low level of polyunsaturated fatty acids (17.8% of total lipids), in particular linoleic acid (6.9%), was assigned to the special features of the composition of meat under investigation. With that, quite high content of saturated fatty acids (48.6% of total lipids) was observed, which explained increased meat stability to oxidative spoilage during long-term storage and processing. The content of calcium in the reindeer meat from the Vorkuta district was 72.25 mg/kg, potassium - 33.3 g/kg, magnesium - 310.25 mg/kg, iron - 55.54 mg/kg, zinc - 41.89 mg/kg, copper - 4.0 mg/kg. The level of iron, magnesium and copper in this type of meat was significantly higher than the data on reindeer meat presented in the reference literature. Conclusion. The obtained data on the chemical composition of reindeer meat from the Vorkuta district can be a basis for the development of the indicators of its authenticity and in the future can be used for identification in case of the need to confirm species and a region of origin of meat, as well as for solving tasks of formation and promotion of regional brands.

COMPARISON OF INFLUENZA A VIRUS INHIBITION IN VITRO BY SIRNA COMPLEXES WITH CHITOSAN DERIVATIVES, POLYETHYLENEIMINE AND HYBRID POLYARGININE-INORGANIC MICROCAPSULES.

Anti-influenza drugs and vaccines have a limited effect due to the high mutation rate of virus genome. The direct impact on the conservative virus genome regions should significantly improve therapeutic effectiveness. The RNA interference mechanism (RNAi) is one of the modern approaches used to solve this problem. In this work, we have investigated the antiviral activity of small interfering RNA (siRNA) against the influenza A/PR/8/34 (H1N1), targeting conserved regions of NP and PA. Polycations were used for intracellular siRNA delivery: chitosan's derivatives (methylglycol and quaternized chitosan), polyethyleneimine, lipofectamine, and hybrid organic/non-organic microcapsules. A comparative study of these delivery systems with fluorescent labeled siRNA was conducted. The antiviral activity of three small interfering RNAs targeting the NP (NP-717, NP-1496) and PA (PA-1630) influenza A viruses genes was demonstrated, depending on the chosen carrier. The most effective intracellular delivery and antiviral activity were observed for hybrid microcapsules.

Russian and Chinese consumers' acceptability of boar meat patties depending on their sensitivity to androstenone and skatole.

The aim of this work was to study the sensitivity of Chinese and Russian female consumers to androstenone and skatole and to identify their preference for pork patties from entire male pigs compared with those from castrated pigs. One-hundred-twenty women in each country were enrolled. The sensitivity of the consumers to both compounds was tested using smell strips and triangular tests. Pairwise tests were performed comparing patties from castrated male pigs with patties from boars with different levels of androstenone and skatole. Approximately 70% of the Russian and 60% of the Chinese consumers were sensitive to skatole and 37% and 32% were sensitive to androstenone, respectively. Nevertheless, a higher percentage of sensitive Russian consumers compared to Chinese consumers disliked the smell of both compounds. In Russia, the consumers' preferences were higher for patties with low levels of both compounds, while no differences were found in China. In both countries, consumers who were sensitive to skatole also preferred patties with low levels of both compounds. Thus, the levels of androstenone and skatole affect boar patty preferences.

New nanocomposites for SERS studies of living cells and mitochondria.

A great enhancement in Raman scattering (SERS) from heme-containing submembrane biomolecules inside intact erythrocytes and functional mitochondria is demonstrated for the first time using silver-silica beads prepared using a new method involving aerosol pyrolysis with aqueous diamminesilver(i) hydroxide as a unique source of plasmonic nanoparticles for SiO2 microspheres. The recorded SERS spectra reveal a set of characteristic peaks at 750, 1127, 1170, 1371, 1565, 1585 and 1638 cm-1, resulting from the normal group vibrations of the pyrrole rings, methine bridges and side radicals in the heme molecules. The SERS spectra of functional mitochondria are sensitive to the activity of the mitochondrial electron transport chain, thus making the method a novel label-free approach to monitor the redox state and conformation of cytochromes in their natural cell environment. The developed nanocomposites are highly suitable for the analysis of biological objects due to their robust synthesis and superior spatial and temporal signal reproducibility, which was preserved for a period of at least one year.

[Effect of GDNF on the behavior of ASC mice with high hereditary predisposition to catalepsy].

ASC mice, which were selected for high predisposition to catalepsy, are convenient genetic model for research of central mechanisms related to disorder of motor regulation. The aim of the work was to study the effect of glial cell line-derived neurotrophic factor (GDNF) on catalepsy, locomotor activity, stereotyping behavior in the marble burying test and on the dopamine level in striatum of ASC mice. It was shown that GDNF increased the locomotor activity in the open field, reduced catalepsy expression and stimulated the stereotyping obsessive-compulsive behavior. These changes in behavior were accompanied by increasing dopamine level in striatum.

The role of chain rigidity in lipid self-association: comparative study of dihexanoyl- and disorbyl-phosphatidylcholines.

In the course of structure-function investigations of lipids a phosphatidylcholine molecule with short and rigid tails, di-2,4-hexadienoylphosphatidylcholine (DiSorbPC), was synthesized and studied in comparison with its saturated analog, dihexanoylphosphatidylcholine (DHPC). Conjugated double bonds in the acyl chains in DiSorbPC reduce considerably the number of possible conformers of the lipid within an aggregate. This leads to impaired packing of unsaturated acyl chains and thus, to a surprisingly high (115 Å(2)) area per molecule for DiSorbPC at the air-water interface and failure to form micelles of regular size and shape. Details on DiSorbPC aggregation and packing provided by a set of experimental techniques combined with molecular dynamics simulations are presented.