最新一期



卷 61, 编号 2 (2025)
Articles
The methods of antibacterial activity investigation and mechanism of antimicrobial action of drug molecules encapsulated in delivery systems
摘要
Due to the diversity of the structure and supramolecular architecture of existing antibacterial drug delivery systems, the question of choosing methods for in vitro properties research of the proposed drug forms (DF) and determining the effect of the carrier on the antimicrobial properties of the drug in the research laboratory is especially relevant. The review examines the main microbiological methods of antimicrobial activity investigation that are used in the study of DF, and provides recommendations for choosing a research method in accordance with the type and chemical nature of drug carrier. In addition, instrumental methods and experimental techniques for studying the mechanism of antimicrobial action of DF, as well as in vitro effects, which are most often observed in the literature when the drug is encapsulated in a carrier, are discussed. This review provides the researcher with a strategy for analyzing the antimicrobial properties of the DF based on the system’s physico-chemical properties that allows a more comprehensive assessment of the future prospects of drugs.



Ribosome disorganization and other effects of artificial RNase DL412 on Salmonella enterica cells
摘要
Cationic amphiphile DL412, which has RNase activity (D — DABCO (1,4-diazabicyclo[2.2.2]octane); L4 — tetramethylene linker; 12 — dodecyl residue), was synthesized at the ICBFM SB RAS, and showed pronounced antibacterial properties. A suspension of Salmonella enterica ATCC 14028 cells was incubated with DL412 (5 µM) for 15 and 30 min, or with ciprofloxacin (5 µM, reference compound). Intact cells served as controls. Samples were fixed with formaldehyde (4%, postfixed with 1% OsO4), or by the Reiter-Kellenberger method (1% OsO4, postfixed with 0.5% uranyl acetate), dehydrated and embedded into an Epon-Araldite mixture. Ultrathin sections were examined using an electron microscope Jem 1400 (“Jeol”, Japan). Within 15 min of incubation with compound DL412, visible ribosomes disappeared throughout the cytoplasm of S. enterica cells; In the periplasmic space, a homogeneous substance of average electron density was observed, its penetration into the cytoplasm was noted, in which polymorphic inclusions appeared. The ultrastructure of the nucleoids was significantly disrupted; they became rounded, and the DNA strands “stick together” into bundles. The ultrastructure of the outer membrane remained unchanged. The observed changes in the structure of S. enterica are due to a combination of RNase activity and amphiphilic properties of DL412 and did not differ depending on the fixation method. Such changes were not described in any publication. Our study made it possible for the first time to visualize the influence of RNase activity and the amphiphilic component of the compound DL412, which penetrated into the cell through two bacterial membranes without their visible damage.



Biosynthesis of suberiс acid from glucose through the inverted fatty acid β-oxidation by recombinant Escherichia coli strains
摘要
Using directly engineered derivatives of previously constructed adipate-producing Escherichia coli strains MG1655 lacIQ, ∆ackA-pta, ∆poxB, ∆ldhA, ∆adhE, PL-SDj10-atoB, Ptrc-ideal-4-SDj10-fadB, ∆fadE, PL-SDj10-tesB, ∆yciA, Ptrc-ideal-4-SDj10-fabI, PL-SDj10-paaJ, ∆aceBAK, ∆glcB и MG1655 lacIQ, ∆ackA-pta, ∆poxB, ∆ldhA, ∆adhE, PL-SDj10-atoB, Ptrc-ideal-4-SDj10-fadB, PL-SDj10-tesB, ∆yciA, Ptrc-ideal-4-SDj10-fadE, PL-SDj10-paaJ, ∆aceBAK, ∆glcB the feasibility of suberic acid biosynthesis from glucose by this bacterium resulting from the reversal of the native fatty acid β-oxidation pathway was demonstrated. The condensation of acetyl-CoA with succinyl-CoA and adipyl-CoA was ensured in recombinants by 3-oxoadipyl-CoA thiolase PaaJ, whereas the putative acetyl-CoA C-acetyltransferase YqeF was unable to catalyse the respective reactions. The biosynthesis of ~60 μM suberic acid was achieved upon significant enhancement in the strains of the expression of the bifunctional (S)-3-hydroxyacyl-CoA dehydrogenase/enoyl-CoA reductase gene, fadB. Subsequent inactivation of succinate dehydrogenase in the strains increased the intracellular availability of succinyl-CoA for the initiation of the first round of cycle reversal and favored an increase in the accumulation of the target compound by the recombinants to ~75 μM. The results provide a framework for the development of highly efficient producing strains for bio-based production of suberic acid from renewable raw materials.



Effect of fermentation by Lactobacilli on the organoleptic properties of pea protein isolate
摘要
The work investigated the effect of fermentation with three bacterial preparations (BK-Uglich-K, BK-Uglich- AV and BK-Uglich-P) on the smell and taste of pea protein isolate, as well as on the content of 1-hexanal, phytates and phenolic compounds in the isolate. It was shown that fermentation improves the odor characteristics of the isolate. It was possible to significantly reduce the severity of the bean smell and grassy smell, as well as reduce the content of 1-hexanal. At the same time, fermentation also improved the taste of the isolate: it was possible to significantly reduce the severity of such interfering flavors as bean, tart, bitter and grassy; at the same time, the content of phytates and phenolic compounds in the isolate decreased. The obtained results made it possible to select a bacterial preparation (BK-Uglich-AV) to improve the organoleptic parameters of pea protein isolates intended for the production of analogues of meat and dairy products.



Respiratory activity and biosynthesis of alkaloids by the fungus Penicillium citrinum Thom
摘要
The fungus Penicillium citrinum VKM F-4043D isolated from ancient permafrost deposits in the Arctic is an active producer of quinoline alkaloids (quinocitrinines A and B) and clavine ergot alkaloids (agroclavine-I and epoxyagroclavine-I). During fungal growth in a medium with two non-fermentable substrates — succinate and mannitol, the dynamics of respiratory activity was studied. Oxygen consumption by cells was shown to be associated with the dynamics of two-phase synthesis of biomass and alkaloids, the maximum respiratory activity had been coincided with the maximum rates of alkaloid synthesis and biomass accumulation. As shown by inhibitory analysis of fungal respiration, along with the main, cytochrome, respiratory chain, an alternative, cyanide-resistant, electron transfer pathway functions, which is suppressed by benzhydroxamic acid. It has been shown that the fungus P. citrinum is capable of growing in the presence of antimycin A, an inhibitor of electron transfer in the cytochrome region of the respiratory chain. In this case, the alternative oxidase functions as the only terminal oxidase capable of supporting fungal growth and alkaloid biosynthesis. When glucose was used as a growth substrate, biosynthesis of both alkaloids and cyanide-resistant oxidase was not observed.



Modulation of antioxidant enzyme activity levels and chaperone levels in different Cucurbitaceae genotypes under heat stress
摘要
Factors determining plant resistance to abiotic stress include many stress defense systems. The most significant of them are the antioxidant and chaperone systems. However, the mechanisms of interaction between these systems have not been sufficiently studied. In this work, we studied the effect of heat stress on the activity levels of antioxidant enzymes (superoxide dismutase; SOD and catalase; CAT) and the levels of heat shock proteins (cytoplasmic HSP70 and chloroplast HSP70B) in the leaves of pumpkin seedlings of three genotypes (Cucurbita moschata, C. pepo, C. maxima) differing in their resistance to environmental stress. It was shown that under heat stress, the levels of CAT activity increased in all the studied genotypes. After heat stress, a noticeable drop (48.9%) in the level of CuZn-SOD activity was shown in C. moschata, compared with an increase in the enzyme activity by (2–14.6%) in the other two genotypes. The level of cytoplasmic HSP70 proteins decreased by 36, and chloroplast HSP70B by 34% in C. moschata plant cells after heat stress. In contrast, the level of cytoplasmic heat shock proteins HSP70 increased in C. pepo and C. maxima genotypes by 20 and 18%, respectively, and in the case of chloroplast HSP70B proteins, the increase was 43 and 10%. It was found that the modulation of the activity levels of CuZn-SOD (the main representative of the enzyme in the cell) and the levels of cytoplasmic HSP70 and chloroplast HSP70B chaperones in Cucurbitaceae genotypes is coordinated, indicating the interaction of these two cellular defense systems under heat stress. Thus, HSP70, HSP70B levels and CuZn-SOD activity levels are reliable early warning signals of heat stress, allowing the stress to be detected before it causes serious damage to the plant.



Growth-regulating activity of brassinosteroid compositions with ferulic acid on spring wheat plants
摘要
The influence of steroid phytohormones (24-epibrassinolide and 24-epicastasterone), ferulic acid and their mixtures at all stages of ontogenesis on growth, morphoformation, physiological and biochemical processes and grain productivity of spring wheat (Triticum aestivum L.) was studied. Compounds and their mixtures (in equimolar ratio) were used by spraying plants with solutions of substances in optimal concentrations. The dynamics of changes in the content of steroid phytohormones at the early stages of plant development and ontogenesis have been studied. It was shown that treatment of plants by spraying with brassinosteroids or ferulic acid led to the activation of growth processes, the productivity of morphogenesis and reproduction, and an increase in the level of endogenous brassinosteroids, free radical oxidation and pigments. The combined use of brassinosteroids and ferulic acid increased the effectiveness of their action, exhibiting a synergistic interaction in stimulating growth and metabolic processes and leading to an increase in yield, as well as an improvement in grain quality.



Effect of the mineral composition of sulfide raw materials on bioleaching of sulfide minerals
摘要
Bioleaching of nickel-copper sulfide ore, 2 sulfide copper-nickel concentrates, and copper-zinc concentrate was studied. It was shown that specific rates of nickel leaching were similar in experiments with all studied raw materials. It was 59.3, 58.7, and 54.4 mg/(g·d) in the case of the ore, concentrate 1, and concentrate 2, respectively. Specific rate of zinc leaching from copper-zinc concentrate was 248.6 mg/(g·d). Copper extraction level reached 98.5%, while its content decreased from 7.4% (in the concentrate) to 0.21% (leaching residue). Specific copper leaching rate (7.3–14.8 mg/(g·d)) was lower than those of nickel and zinc. In contrast to nickel and zinc, copper content in bioleaching residue increased in comparison to the concentrate: in the case of copper-nickel concentrates it increased from 15.1 to 17.8% (concentrate 1) and from 19.1 to 19.7% (concentrate 2), while in the case of copper-zinc concentrate, it increased from 10.1 to 16.1%. Thus, bioleaching of all studied concentrates made it possible to obtain copper concentrates with comparatively high copper content (16–19%), which can be commercial products for pyrometallurgy. A comparative analysis of the leaching processes of the selected raw materials will allow to assess the prospects of using the approach under study for processing concentrates and ores of various compositions and with different ratios of non-ferrous metal minerals.



Combined systems of recombinase polymerase amplification and membrane immunochromatography or enzyme linked immunoassay for quantitative determination of Salmonella enterica bacterial DNA
摘要
The combined bioanalytical systems for the detection of Salmonella enterica bacteria in milk have been developed and studied. These test systems are based on isothermal recombinase polymerase amplification (RPA) of a fragment of the invA gene and detection of the DNA amplicons containing biotin and fluorescein residues by a rapid membrane chromatography on test strips or an enzyme-linked immunosorbent assay (ELISA) in microplates. It was shown that the developed test systems are specific, sensitive and easy to perform. The RPA procedure requires 20 min at a temperature of 40°C. The immunochromatographic detection of amplicons provides rapid testing within 10 min as well as possible visual recording of the result. ELISA takes 75 min, allows to analyze a large number of samples and quantify the result. It has been established that the developed bioanalytical systems are characterized by broad specificity for various serotypes of Salmonella enterica subspecies enterica, belonging to serogroups B, C, D and E. The detection limit of genomic DNA of S. enterica in the test systems was 0.5 fg. The detection limit of Salmonella enterica bacteria in artificially contaminated milk samples was 8 × 102 CFU/ml. After enrichment for 6 h, the detection limit proved to be 2 × 100 CFU per 25 g of milk.



Determination of bacterial sensitivity to a bacteriophage by using a compact acoustic analyzer
摘要
The work demonstrates for the first time the potential of a compact acoustic sensor system for assessing the impact of bacteriophages on microbial cells and assessing their bacteriophage sensitivity. It was found that using the developed system one can evaluate the activity of bacteriophages against microbial cells within 5 min without taking into account the time of cultivating microbial cells for analysis. The results obtained are promising for the further development of the acoustic sensory system in the phage therapy.



Congratulations to Doctor of Biological Sciences Alexey Fedorovich Topunov on his 70th birthday
Congratulations to doctor of biological sciences Alexey Fedorovich Topunov on his 70th birthday


