Victor V. Revin

Mitochondrial Aging and Age-Related Dysfunction of Mitochondria

Age-related changes in mitochondria are associated with decline in mitochondrial function. With advanced age, mitochondrial DNA volume, integrity and functionality decrease due to accumulation of mutations and oxidative damage induced by reactive oxygen species (ROS). In aged subjects, mitochondria are characterized by impaired function such as lowered oxidative capacity, reduced oxidative phosphorylation, decreased ATP production, significant increase in ROS generation, and diminished antioxidant defense. Mitochondrial biogenesis declines with age due to alterations in mitochondrial dynamics and inhibition of mitophagy, an autophagy process that removes dysfunctional mitochondria. Age-dependent abnormalities in mitochondrial quality control further weaken and impair mitochondrial function. In aged tissues, enhanced mitochondria-mediated apoptosis contributes to an increase in the percentage of apoptotic cells. However, implementation of strategies such as caloric restriction and regular physical training may delay mitochondrial aging and attenuate the age-related phenotype in humans.

Effect of wood modification on lignin consumption and synthesis of lignolytic enzymes by the fungus Panus (Lentinus) tigrinus

Lignin consumption and synthesis of lignolytic enzymes by the fungus Panus (Lentinus) tigrinuscultivated on solid phase (modified and unmodified birch and pine sawdusts) were studied. The fungus grew better on and consumed more readily the birch lignin than the pine wood. Peroxidase activity was higher in the case of pine sawdust; laccase and lignolytic activities, in the case of birth sawdust. Treatment with ammonia or sulfuric acid decreased lignin consumption by this fungus cultivated on either medium. Modification of sawdust by ultrasound increased lignin consumption and may be recommended for accelerating biodegradation of lignocellulose substrates.

Optimizing the Conditions of Dextran Synthesis by the Bacterium Leuconostoc mesenteroides Grown in a Molasses-Containing Medium

Maximal dextran production (54–55 g/l) by the bacterium Leuconostoc mesenteroides strain V-2317D was observed in molasses-containing media in the presence of 17.5% glucose at pHinit 6.75. The beginning of dextran production depended on the amount of inoculate; maximum yield was observed at a shaker rate of 200 rpm. The dextran produced by L. mesenteroides grown in the molasses-containing medium was representative of three fractions differing in molecular weight and composition: the high-(∼54.5%), medium- (∼ 27.9%), and low-molecular-weight (∼2.85%) fractions.

The effect of copper ions on the production of laccase by the fungus Lentinus (Panus) tigrinus

The basidiomycete Lentinus tigrinus was cultured in media containing copper ions added at different growth stages. Copper ions at increased concentrations decelerated of the fungal biomass accumulation. The later Cu2+ ions were added, the better the fungal mycelium developed, and the toxic effect of Cu2+ was less pronounced. The maximum laccase activity (47 U/ml) was observed in the presence of 1.5–2.0 mM Cu2+ added on day 4 of cultivation.

Quantitative Assessment of Heteroplasmy of Mitochondrial Genome: Perspectives in Diagnostics and Methodological Pitfalls

The role of alterations of mitochondrial DNA (mtDNA) in the development of human pathologies is not understood well. Most of mitochondrial mutations are characterized by the phenomenon of heteroplasmy which is defined as the presence of a mixture of more than one type of an organellar genome within a cell or tissue. The level of heteroplasmy varies in wide range, and the expression of disease is dependent on the percent of alleles bearing mutations, thus allowing consumption that an upper threshold level may exist beyond which the mitochondrial function collapses. Recent findings have demonstrated that some mtDNA heteroplasmic mutations are associated with widely spread chronic diseases, including atherosclerosis and cancer. Actually, each etiological mtDNA mutation has its own heteroplasmy threshold that needs to be measured. Therefore, quantitative evaluation of a mutant allele of mitochondrial genome is an obvious methodological challenge, since it may be a keystone for diagnostics of individual genetic predisposition to the disease. This review provides a comprehensive comparison of methods applicable to the measurement of heteroplasmy level of mitochondrial mutations associated with the development of pathology, in particular, in atherosclerosis and its clinical manifestations.

Vascular Endothelium: Functioning in Norm, Changes in Atherosclerosis and Current Dietary Approaches to Improve Endothelial Function

The endothelium represents not only a simple cellular monolayer that lines the vascular tree in humans and other vertebrates. Depending on the location, the endothelium shows significant morphological and functional heterogeneity through differentiated expression of pro- and anticoagulant factors, presence and frequency of intercellular contacts, variable contractility, cell shape, and volume. Altogether, these properties are crucial for adjustment of the endothelial function and further maintenance of the adequate homeostasis in response in local microenvironmental changes. Endothelial cells (ECs) play a critical role in coordinated regulation of blood flow. This is achieved due to the capacity of ECs to create the active anti-thrombotic surface that supports blood fluidity and transfer of blood cells and biomolecules. However, in certain vascular regions that can occur in inflamed sites or in sites with high hydrodynamic shear stress, ECs could lost their anti-thrombotic properties and switch their normal quiescent phenotype towards the prothrombotic, proadhesion, and proinflammatory state. In such an athero-prone site, the proper endothelial function is impaired that increases risk for formation of the atherosclerotic plaque. The endothelial dysfunction not only precedes atherosclerosis but greatly contributes to atherogenesis in all disease stages. Healthy lifestyle and regular intake of correct antioxidant-rich diet such as fresh fruits, vegetables, olive oil, red wine, and tea have beneficial effects on endothelial function and could therefore reduce the cardiovascular risk.

Extracellular oxidases of the lignin-degrading fungus Panus tigrinus.

Two extracellular oxidases (laccases) were isolated from the extracellular fluid of the fungus Panus (Lentinus) tigrinus cultivated in low-nitrogen medium supplemented with birch sawdust. The enzymes were purified by successive chromatography on columns with TEAE-cellulose and DEAE-Toyopearl 650M. Both oxidases catalyze oxidation of pyrocatechol and ABTS. Moreover, oxidase 1 also catalyzes oxidation of guaiacol, o-phenylenediamine, and syringaldazine. The enzymes have identical pH (7.0) and temperature (60–65°C) optimums. Absorption spectra of the oxidases differ from the spectra of typical “blue” laccases and are similar to the spectrum of yellow oxidase.

The impact of interferon-regulatory factors to macrophage differentiation and polarization into M1 and M2

The mononuclear phagocytes control the body homeostasis through the involvement in resolving tissue injury and further wound healing. Indeed, local tissue microenvironmental changes can significantly influence the functional behavior of monocytes and macrophages. Such microenvironmental changes for example occur in an atherosclerotic plaque during all progression stages. In response to exogenous stimuli, macrophages show a great phenotypic plasticity and heterogeneity. Exposure of monocytes to inflammatory or anti-inflammatory conditions also induces predominant differentiation to proinflammatory (M1) or anti-inflammatory (M2) macrophage subsets and phenotype switch between macrophage subsets. The phenotype transition is accompanied with great changes in the macrophage transcriptome and regulatory networks. Interferon-regulatory factors (IRFs) play a key role in hematopoietic development of monocytes, their differentiation to macrophages, and regulating macrophage maturation, phenotypic polarization, phenotypic switch, and function. Of 9 IRFs, at least 3 (IRF-1, IRF-5, and IRF-8) are involved in the commitment of proinflammatory M1 whereas IRF-3 and IRF-4 control M2 polarization. The role of IRF-2 is context-dependent. The IRF impact on macrophage phenotype plasticity and heterogeneity is complex and involves activating and repressive function in triggering transcription of target genes.

The role of laccase and peroxidase of Lentinus (Panus) tigrinus fungus in biodegradation of high phenol concentrations in liquid medium

The possibility of the usage of Lentinus tigrinus fungus strain VKM F-3616D for biodegradation of high (up to 5%) phenol concentrations in liquid medium and the involvement of laccase and peroxidase in this process have been studied. L. tigrinus fungus was demonstrated to effectively degrade phenol with easy biomass deletion from the liquid. Decrease in phenol concentration was accompanied by increased secretion level and laccase activity at the preliminary stages of biodegradation, while that of peroxidase was at the latest stages of biodegradation. These enzyme secretions in distinct ratios and consequences are necessary for effective phenol biodegradation. An effective approach for phenol concentration decrease in the waste water of smoking shops in meat-processing factories using L. tigrinus fungus was described.

Increased Secretion of Lignolytic Enzymes by the Lentinus tigrinus Fungus after Addition of Butanol and Toluene in Submerged Cultivation

We studied the effects of butanol and toluene on secretion of lignolytic enzymes by the Lentinus tigrinus fungus during submerged cultivation. Addition of butanol and toluene during the trophophase was followed by an increase in laccase and peroxidase activity of the culture and change in the composition of phospholipids and fatty acids. The ratio of phosphatidylcholine and phosphatidic acid decreased, while the amount of lysophosphatidylcholine, phosphatidylethanolamine, phosphoinositides, phosphatidylserine, and unsaturated fatty acids decreased. These changes resulted in an increase in the unsaturation index.