卷 55, 编号 2 (2019)

Reversible protein binding with membrane components and the cytoskeleton is one of mechanisms of cell metabolism control. This is a crucial mechanism for the regulation of metabolism in nuclear-free cells, mammal erythrocytes, in which it is realized via hemoglobin modification to the membrane-bound state. Hemoglobin can interact with the membrane in different ligands and redox statuses. Thus, this protein can function as a sensor of redox and oxygen conditions. Depending on the oxygen conditions, deoxyHb changes the energetic metabolism, morphology, and deformability of erytrocytes, as well as the release of vascular tone regulators, NO and ATP. This is fulfilled via interaction with the main integral protein of erythrocyte membrane, the band 3 protein. The products of hemoglobin oxidative denaturation, irreversible hemichromes, also carry out a signaling function. Accumulating over time or as result of oxidative stress, chemichromes contain information on the redox conditions and the longevity of erythrocyte functioning. It has been hypothesized that erythrocytes have a program that initiates intracellular hemolysis. The participation of hemoglobin and its membrane-bound form (MBHb) in the realization of this program is discussed. The role of NO donors in the regulation of erythrocyte stability is debated as well. The use of data on the MBHb content in erythrocytes is proposed for clinical diagnostics.

L-lysine-imprinted polymeric sorbents based on methacrylic acid and ethylene glycol dimethacrylate have been synthesized. The equilibrium and kinetics of amino acid sorption on the synthesized sorbents and control sorbent (a nonimprinted analog) are compared. It is shown that the enantioselective separation of the D,L-lysine racemic mixture was most effectively performed on polymeric sorbent synthesized in the presence of 6 mol % L-lysine. The amino acid was fixed on the surface layer of this sorbent at energy-equivalent, specific binding sites.

Ginsenosides Rb1, Rb2 and Re were converted into corresponding intermediates and aglycones using a multienzyme complex produced by Cellulosimicrobium cellulans F16. The whole conversion processes were monitored at different time points by UPLC-PDA-MS. The hydrolysates and the conversion routes were identified using standard samples and electrospray ionization MS. Ginsenosides Rb1, Rb2, and Re were finally converted to the product protopanaxadiol and ginsenoside Rg2. The results indicated that the multienzyme complex Xyl I produced by C. cellulans F16 can be an efficient tool for the transformation of ginsenosides.

The new natural 36DCP strain, which is capable of using 4-chlorophenoxyacetic acid (4-CPA) as the sole source of carbon and energy, was characterized. A culture isolated from a soil sample contaminated with chemical waste was identified according to physiological, biochemical, cultural, morphological features and analysis of the 16S rRNA gene sequence as a strain belonging to the Pseudomonas genus. In the batch culture, Pseudomonas sp. 36DCP degraded 45% of 4-CPA from the initial concentration after 5 days of incubation. Based on the identified intermediate metabolites in the culture medium (para-benzoquinone and hydroquinone), it was found that the conversion of 4-CPA in Pseudomonas sp. 36DCP proceeds through the hydroquinone pathway. This degradation pathway of monochlorinated phenoxyacetic acids has not previously been described in bacteria.

The ability of 22 strains of the Emericellopsis alkalina species to synthesize the antimicrobial peptaiboles A118-35, A118-36, and A118-37 with antifungal activity was studied. The ability to synthesize peptaibols is typical for 72% of the studied strains of the species. It was established that peptaibol production is a strain-specific feature and depends on the cultivation conditions and the concentration of sugars and carbon sources. The isolated peptaibol A118-37 was active against opportunistic Candida albicans yeast and Apergillus niger mold fungus, as well as against clinical fungal isolates of mycosis pathogens with multiple resistance.

Lactate dehydrogenase activity (LDH, EC 1.1.1.27) was induced in pea (Pisum sativum L.) leaves by culturing plants under flood conditions. The enzyme was purified to an electrophoretic homogeneous state with a multistage purification process including ammonium sulfate fractionation, ion exchange chromatography on DEAE-sephacel, and gel chromatography on Sephadex G-200. The LDH preparation had a specific activity of 41.9 E/mg protein, with a purification rate of 101 and a yield of 26.8%. Its physical and chemical features were studied. The molecular weight of the native LDH molecule (148 kD) was determined, and the enzyme was shown to consist of four subunits, the molecular mass of which was determined by PAGE-Na electrophoresis in the presence of SDS-Na equal to 37 kD. The kinetic and regulatory properties, such as the Michaelis constants, the substrate inhibition constants, the effects of hydrogen-ion and temperature on the direct and reverse reactions, were studied.

The effect of the colonization of barley plants (Hordeum vulgare L.) by the associative microorganisms Pseudomonas putida BS3701 on the adaptation of the photosynthetic apparatus to high light intensity was studied. A number of differences were found in the functioning and structure of the photosynthetic apparatus of the control plants and plants colonized by P. putida BS3701 grown at 100 µmol quanta/m² s. The barley plants colonized by P. putida BS3701 were shown to have an increased resistance to high light intensity (1000 µmol quanta/m² s) when compared to the control plants. It was established that the adaptive decrease in the PSII antenna size was characterized by the same molecular mechanism in both the control plants and plants colonized by P. putida ВS3701. However, the decrease in PSII antenna size was more pronounced in plants colonized by P. putida ВS3701. It can be assumed that this might be the cause of more efficient protection of the photosynthetic apparatus of plants colonized by P. putida BS3701 against photoinhibition under high illumination.

Three bacterial strains (SPB1, SPB2, and SPB3) isolated from the activated sludge of treatment facilities most efficiently oxidized (as compared to other strains) a model solution based on glucose and glutamic acid in the presence of a ferrocene mediator. The possible use of isolated strains as a basis for a mediator-type amperometric BOD biosensor was studied. Analysis of 16S rRNA genes demonstrated that the SPB1, SPB2, and SPB3 strains are 99.79–100% similar to the Paracoccus yeei BAA-599^T, Pseudomonas veronii DSM 11331^T, and Bacillus proteolyticus TD42^T strains, respectively. It was established that the bioreceptor element based on the P. yeei SPB1 strain possessed the best characteristics. It was stable in storage at 4°С for 22 days, and the lower limit of detectable concentrations was 1.3 mg О₂/dm³. In order to search for the most efficient electron transfer mediator for this strain, nine compounds, including ferrocene, thionine, methylene blue, potassium hexacyanoferrate(III), and 2,6-dichlorophenolindophenol, were screened. The mediator electron transfer signals were obtained for each of them. Ferrocene was the most efficient in terms of sensitivity and the amount of substrate oxidation that can be registered in the presence of the mediator. An analysis of ten samples of wastewater (before and after purification) and the rivers of Tula oblast demonstrated that the use of ferrocene and P. yeei SPB1 strain cells made it possible to obtain data with a high correlation (R = 0.9934) with the results of the standard method.