Publications by authors named "Vladimir I Tishkov"

The problem of antibiotic resistance is currently very acute. Numerous research and development of new antibacterial drugs are being carried out that could help cope with various infectious agents. One of the promising directions for the search for new antibacterial drugs is the search among the probiotic strains present in the human gastrointestinal tract.

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Ribonucleoside hydrolases are enzymes that catalyze the cleavage of ribonucleosides to nitrogenous bases and ribose. These enzymes are found in many organisms: bacteria, archaea, protozoa, metazoans, yeasts, fungi and plants. Despite the simple reaction catalyzed by these enzymes, their physiological role in most organisms remains unclear.

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The expression of multifunctional proteins can facilitate the setup of a biotechnology process that requires multiple functions absolved by different proteins. Herein the functional and conformational characterization of a formate dehydrogenase-monooxygenase chimera enzyme is presented. The fused enzyme (FDH-PAMO) was prepared by linking the C-terminus of the mutant NADP-dependent formate dehydrogenase from Pseudomonas sp.

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In order to accelerate Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), here we propose an optimized version of the technique enabled by experimental tuning reinforced by theoretical description. In the resulting system, the gel buffer was diluted twofold and supplemented with glycine at a low concentration, whereas a higher voltage was applied. This approach reduced runtime from 90 to 18 min.

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Article Synopsis
  • Oxidized nicotinamide adenine dinucleotide (NAD) is crucial for cellular metabolism and signaling, and this research develops a reliable enzymatic assay to measure NAD levels in human blood.
  • The study compares NAD concentrations between healthy individuals and patients with cardiac or neurological diseases, finding significant reductions in NAD levels among these patient groups.
  • The assay not only confirms expected NAD levels in healthy subjects but also highlights its potential as a diagnostic tool by offering better differentiation between cardiac and neurological patients through NAD ratio comparisons with other blood markers.
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  • This study compares the effectiveness of 2-oxoglutarate mimetics and branched-tail oxyquinoline inhibitors in activating HIF prolyl hydroxylase, focusing on their performance in a luciferase reporter assay.
  • Novel oxyquinoline inhibitors identified in this research showed significantly higher potency than existing drugs like roxadustat and vadadustat, especially when 2-methyl substitution was applied.
  • Transcriptomic analysis revealed that the new inhibitors stimulated HIF1 and HIF2 pathways similarly to roxadustat but had distinct effects on alternative pathways involving p53 and NF-κB, suggesting a specific action of the 2-methyl variant on HIF PHD2.
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  • Researchers fused genes from cytochrome P450 BM3 and formate dehydrogenase to create multifunctional enzymes aimed at improving stability and activity.
  • The study varied the arrangement of the genes and linkers and compared the fused enzymes with individual ones in terms of substrate conversion and stability.
  • A significant increase in activity (up to threefold) was noted for the fusion constructs, indicating that the fusion may cause conformational changes in P450 BM3, although no NADPH channeling was observed.
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  • - The increasing importance of NAD in medical research necessitates efficient methods for quantifying it in complex samples.
  • - A novel fluorometric assay using formate dehydrogenase allows for specific and straightforward measurement of NAD without needing complicated separation techniques.
  • - This method has been successfully tested on rat brain cortex and mitochondria extracts, demonstrating its reliability and stability in various conditions.
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The emergence of new antibiotic-resistant bacterial strains means it is increasingly important to find alternatives to traditional antibiotics, such as bacteriolytic enzymes. The bacteriolytic enzyme lysozyme is widely used in medicine as an antimicrobial agent, and covalent immobilization of lysozyme can expand its range of possible applications. However, information on the effect of such immobilized preparations on whole bacterial cells is quite limited.

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Background: "Branched tail" oxyquinolines, and adaptaquin in particular, are potent HIF prolyl hydroxylase inhibitors showing promising results in in vivo hemorrhagic stroke models. The further improvement of the potency resulted in identification of a number of adaptaquin analogs. Early evaluation of toxicity and metabolism is desired right at the step of lead selection.

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L-Ascorbate (L-Asc), but not D-isoascorbate (D-Asc) and N-acetylcysteine (NAC) suppress HIF1 ODD-luc reporter activation induced by various inhibitors of HIF prolyl hydroxylase (PHD). The efficiency of suppression by L-Asc was sensitive to the nature of HIF PHD inhibitor chosen for reporter activation. In particular, the inhibitors developed to compete with alpha-ketoglutarate (αKG), were less sensitive to suppression by the physiological range of L-Asc (40-100 μM) than those having a strong iron chelation motif.

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  • Flavonoids can activate genetic responses to low oxygen and oxidative stress by interacting with estrogen receptors or activating certain kinases.
  • * The study evaluated various compounds like flavones and catechols to identify their ability to stabilize key transcription factors HIF1 and Nrf2, which are crucial for hypoxic and antioxidant defenses.
  • * It was found that NDGA, a compound from the Creosote bush, effectively stabilizes HIF1 and Nrf2 and shows strong neuroprotective effects in a Parkinson's Disease animal model, outperforming typical flavonoids due to its better bioavailability and stability.
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Endo-1,4-β-glucanase from Penicillium verruculosum (PvEGIII) belongs to family 12 of glycoside hydrolases (GH12). Analysis of the enzyme 3D model structure showed that the amino acid residue Asp98 may directly affect the pH-profile of enzyme activity since it is located at the distance of hydrogen bond formation from Glu203 that plays the role of a general acid in catalysis. The gene encoding the PvEGIII was cloned into Escherichia coli.

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The analysis of the 3D model structure of the ternary complex of recombinant formate dehydrogenase from soya Glycine max (EC 1.2.1.

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New small cytochrome c (TniCYT) was purified from haloalkaliphilic sulfur-oxidizing bacterium Thioalkalivibrio nitratireducens. The protein was analyzed by mass spectrometry as well as using visible, CD and EPR spectroscopy. It was found that TniCYT is a monomer with a molecular mass of 9461 Da which contains two hemes per molecule.

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This paper describes the clonal diversity of vancomycin-resistant Enterococcus faecium isolated from patients with haematological malignancies in Russia. Pulsed-field gel electrophoresis (PFGE) typing of 129 vanA-positive E. faecium strains revealed 23 independent restriction profiles with two predominant clonal types.

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A membrane-based high-throughput screening (HTS) assay for active D-amino acid oxidase (DAAO) in liquid samples as well as in intact Escherichia coli cells has been developed and optimized. The detection limit of the assay was less than 1 ng per sample. The method proposed can be used for quantitative DAAO determination in the range of 0.

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The role of the conserved glutamic acid residue in anionic plant peroxidases with regard to substrate specificity and stability was examined. A Glu141Phe substitution was generated in tobacco anionic peroxidase (TOP) to mimic neutral plant peroxidases such as horseradish peroxidase C (HRP C). The newly constructed enzyme was compared to wild-type recombinant TOP and HRP C expressed in E.

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Laccases are members of the blue multi-copper oxidase family that oxidize substrate molecules by accepting electrons at a mononuclear copper centre and transferring them to a trinuclear centre. Dioxygen binds to the trinuclear centre and, following the transfer of four electrons, is reduced to two molecules of water. Crystals of the laccase from Cerrena maxima have been obtained and X-ray data were collected to 1.

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Laccases are members of the blue multi-copper oxidase family. These enzymes oxidize substrate molecules by accepting electrons at a mononuclear copper centre and transferring them to a trinuclear centre. Dioxygen binds to the trinuclear centre and following the transfer of four electrons is reduced to two molecules of water.

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