Prikladnaia biokhimiia i mikrobiologiia最新文献

In this review we summarize the available research on enzymatic biocatalysis in the chemical synthesis of drugs. We focus on oxydoreductsases, particularly ketoreductases, that are widely used in biotechnological processes: alpha- and omega-transaminases, lipases, nitrile hydrolases, and aldolases. The potential for the extended use of novel enzymes produced via bioengineering is discussed.

It has been shown that the membranotropic homeostatic tissue-specific bioregulator isolated from rat liver tissue contains a nanosized peptide-protein complex consisting of low-molecular peptides (1–6.5 kDa) and a protein from the serum albumin family. This bioregulator modulated the peptide biological activity and determined the tissue specificity.

Cytokines are a family of signaling polypeptides involved in cell-cell interactions in the process of the immune response, as well as in the regulation of a number of normal physiological functions. Cytokines are used in medicine for the treatment of cancer, immune disorders, viral infections, and other socially significant diseases, but the extent of their use is limited by the high production cost of the active agent. The development of this area of pharmacology is associated with the success of genetic engineering, which allows the production of significant amounts of protein by transgenic organisms. The review discusses the latest advances in the production of various cytokines with the use of genetically modified plants.

The content of apigenin, naringenin, pisatin, dibutyl-ortho-phthalate, and N-phenyl-2-naphthyl-amine were assayed in root exudates of pea (Pisum sativum L.) seedlings one day after their inoculation with Rhizobium leguminosarum, bv. viceae or Pseudomonas siringae pv. pisi, which represent, respectively, mutualistic and antagonistic strategies of interaction with a host plant. After inoculation with either bacteria, the concentrations of apigenin and pisatin in the root exudates were equal, whereas the concentrations of naringenin and N-phenyl-2-naphthylamine were different and those of dibutyl-o-phthalate were unchanged. A certain role is suggested for the phenolic compounds in an accomplishment of symbiotic relations of bacteria with a host plant.

A number of alkylated (quaternized) and acylated derivatives of low-molecular weight chitosan were obtained. The structure and composition of the compounds were confirmed by the results of IR and PMR spectroscopy, as well as conductometric titration. The effect of the acyl substituent and the degree of substitution of N-(2-hydroxy-3-trimethylammonium) with the propyl fragment appended to amino groups of the C2 atom of polymer chains on antibacterial activity against typical representatives of gram-positive and gram-negative microorganisms (Staphylococcus epidermidis and Escherichia coli) was studied. The highest activity was in the case of N-[(2-hydroxy-3-trimethylammonium)propyl]chitosan chloride with the maximal substitution (98%). The minimal inhibitory concentration of the derivative was 0.48 µg/mL and 3.90 µg/mL for S. epidermis and E. coli, respectively.

The aim of the work was to find the mode of cultivation of unicellular flagellate Euglena gracilis, favorable for the simultaneous accumulation of α-tocopherol and β-carotene. Cells were grown either in photoautotrophic or photoheterotrophic conditions in the presence of 100 mM ethanol (variant Et) or 40 mM glutamate (variant Gt), or their combination (variant EtGt). The exogenous substrates significantly stimulated light-dependent growth of E. gracilis. The largest increase of biomass was recorded on the 20th day in the variant EtGt and exceeded the autotrophic control by 7 times. The content of β-carotene and chlorophyll (Chl) per cell in mixotrophic cultures exceeded the control by 2-3 and 1.6-2 times, respectively. At the same time, α-tocopherol accumulation in autotrophic cells was greater than in the cells of mixotrophic cultures by 2-7 times. Total yield of tocopherol per unit volume of culture medium, which depended not only on its intracellular content, but also on the amount of accumulated biomass was highest in EtGt variant. A correlation between the accumulation of the antioxidants and the equilibrium concentration of oxygen in the growth medium, which depended on the intensities of photosynthesis and respiration has been analyzed.

Fluorescent and optical spectroscopy were used to study the interaction of alcohol dehydrogenase (ADH) with negatively charged polystyrene sulfonate (PSS) and dextran sulfate (DS), as well as positively charged poly(diallyldimethylammonium) (PDADMA). As found, DS and PDADMA did not affect the structural and catalytic enzyme properties. In contrast, PSS slightly decreased the protein self-fluorescence over 1 h of incubation, which is associated with partial destruction of its quaternary (globular) structure. Investigation of the ADH activity with and without PSS showed its dependency on the incubation time and the PSS presence. Sodium chloride (2.0 M and 0.2 M) or ammonium sulfate (0.1 M) added to the reaction mixture did not completely protect the enzyme quaternary structure from the PSS action. However ammonium sulfate or 0.2 M sodium chloride stabilized the enzyme and partially inhibited the negative PSS effect.

A platform for the cloning and expression of active human butyrylcholinesterase (BuChE) in the yeast Pichia pastoris is first presented. Genetic constructs for BuChE gene expression, separately and in conjunction with a proline-rich peptide called proline-rich attachment domain (PRAD), are based on the vector pPICZαA. It is shown that the highest level of production is achieved in the expression of a BuChE gene without PRAD pPICZαA. It is found that one can obtain up to 125 mg of active enzyme from 1 L of culture medium at an optimal pH environment (pH 7.6), an optical seed culture density of 3 o.u., and an optimum methanol addition mode of (0.5% methanol in the first day and 0.2% thereafter from the second day).

The influence of colonization of the pea (Pisum sativum L.) by aerobic methylobacteria of five different species (Methylophilus flavus Ship, Methylobacterium extorquens G10, Methylobacillus arboreus Iva, Methylopila musalis MUSA, Methylopila turkiensis Sidel) on plant resistance to paraquat-induced stresses has been studied. The normal conditions of pea colonization by methylobacteria were characterized by a decrease in the activity of antioxidant enzymes (superoxide dismutase, catalase, and peroxidases) and in the concentrations of endogenous H2O2, proline, and malonic dialdehyde, which is a product of lipid peroxidation and indicator of damage to plant cell membranes, and an increase in the activity of the photosynthetic apparatus (the content of chlorophylls a, b and carotenoids). In the presence of paraquat, the colonized plants had higher activities of antioxidant enzymes, stable photosynthetic indices, and a less intensive accumulation of the products of lipid peroxidation as compared to noncolonized plants. Thus, colonization by methylobacteria considerably increased the adaptive protection of pea plants to the paraquat-induced oxidative stress.

Three malate dehydrogenase isoforms (65-, 60-, and 71-fold purifications) with specific activities of 4.23, 3.88, and 4.56 U/mg protein were obtained in an electrophoretically homogenous state from Rhodovulum steppense bacteria strain A-20s chemotropically grown under aerobic conditions. The physicochemical and kinetic properties of malate dehydrogenase isoforms were determined. The molecular weight and the Michaelis constants were determined; the effect of hydrogen ions on the forward and reverse MDH reaction was studied. The results of the study demonstrated that the enzyme consists of subunits; the molecular weight of subunits was determined by SDS-PAGE.