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result(s) for
"Pavlenko, Victor"
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KLF-1 orchestrates a xenobiotic detoxification program essential for longevity of mitochondrial mutants
2019
Most manipulations that extend lifespan also increase resistance to various stress factors and environmental cues in a range of animals from yeast to mammals. However, the underlying molecular mechanisms regulating stress resistance during aging are still largely unknown. Here we identify Krüppel-like factor 1 (KLF-1) as a mediator of a cytoprotective response that dictates longevity induced by reduced mitochondrial function. A redox-regulated KLF-1 activation and transfer to the nucleus coincides with the peak of somatic mitochondrial biogenesis that occurs around a transition from larval stage L3 to D1. We further show that KLF-1 activates genes involved in the xenobiotic detoxification programme and identified cytochrome P450 oxidases, the KLF-1 main effectors, as longevity-assurance factors of mitochondrial mutants. Collectively, these findings underline the importance of the xenobiotic detoxification in the mitohormetic, longevity assurance pathway and identify KLF-1 as a central factor in orchestrating this response.
Cytochrome P450 oxidases (CYPs) are enzymes that participate in the xenobiotic detoxification and their expression is enhanced in long-lived model organisms. Here the authors show that KLF-1 promotes
cyp
expression and ensures lifespan extension in
C. elegans
mitomutants by activating mitohormesis.
Journal Article
Succinate Dehydrogenase Upregulation Destabilize Complex I and Limits the Lifespan of gas-1 Mutant
by
Pujol, Claire
,
Bratic-Hench, Ivana
,
Trifunovic, Aleksandra
in
Animals
,
Biology
,
Caenorhabditis elegans
2013
Many Caenorhabditis elegans mutants with dysfunctional mitochondrial electron transport chain are surprisingly long lived. Both short-lived (gas-1(fc21)) and long-lived (nuo-6(qm200)) mutants of mitochondrial complex I have been identified. However, it is not clear what are the pathways determining the difference in longevity. We show that even in a short-lived gas-1(fc21) mutant, many longevity assurance pathways, shown to be important for lifespan prolongation in long-lived mutants, are active. Beside similar dependence on alternative metabolic pathways, short-lived gas-1(fc21) mutants and long-lived nuo-6(qm200) mutants also activate hypoxia-inducible factor -1α (HIF-1α) stress pathway and mitochondrial unfolded protein response (UPR(mt)). The major difference that we detected between mutants of different longevity, is in the massive loss of complex I accompanied by upregulation of complex II levels, only in short-lived, gas-1(fc21) mutant. We show that high levels of complex II negatively regulate longevity in gas-1(fc21) mutant by decreasing the stability of complex I. Furthermore, our results demonstrate that increase in complex I stability, improves mitochondrial function and decreases mitochondrial stress, putting it inside a \"window\" of mitochondrial dysfunction that allows lifespan prolongation.
Journal Article
SPTF-3/SP1 orchestrates mitochondrial biogenesis upon ribosomal stress and acute starvation
2023
When cells have increased energy demand, they respond by elevating the production of new mitochondria through the process of mitochondrial biogenesis. This complex physiological undertaking requires precise coordination of mitochondrial and nuclear gene expression to extend the existing mitochondrial network in the cell. Using C. elegans as a model system we have identified stress-induced transcription factor SPTF-3 as a novel regulator of mitochondrial biogenesis on-demand upon increased heat stress, dietary restriction, and acute starvation. We show that SPTF-3 also regulates ATFS-1, the main transcriptional regulator of UPRmt (mitochondrial unfolded protein response). Thus, by orchestrating two parallel programs – mitochondrial biogenesis and UPRmt, SPTF-3 safeguards mitochondrial wellbeing and function upon stress, thus allowing survival in unfavorable conditions. Mitochondrial biogenesis is induced by disturbances in cytoplasmic ribosomal assembly, which leads to preferential translation of SPTF-3. Importantly, we demonstrated that the role of SPTF-3 in the regulation of mitochondrial biogenesis upon nutrient deprivation is conserved in mammals through its homolog SP1.
Phase Equilibria of the In–Pd–Sn System at 500 °C and 800 °C: Experimental Study and CALPHAD Modeling
by
Kareva, Maria A.
,
Ptashkina, Evgeniya A.
,
Kuznetsov, Victor N.
in
Alloys
,
Analysis
,
Annealing
2023
Phase equilibria in the In–Pd–Sn system were investigated by a combination of key experiments and thermodynamic modeling. Partial isothermal sections at 500 °C and 800 °C of the In–Pd–Sn system for Pd contents above 66 at.% have been plotted experimentally using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX) and X-ray diffraction (XRD). The solubility of the third component in binary compounds InPd3 and Pd3Sn was determined. The new ternary compound τ1 was found in Pd contents ranging from 20 to 25 at.% and at Sn contents varying from 5 to approximately 17 at.% Sn. This compound crystallizes in an Al3Ti-type tetragonal structure. Isostructural InPd2 and Pd2Sn phases from the In–Pd and Pd–Sn binary compositions form a continuous phase field in the ternary system at both temperatures. The temperatures of the solidus, liquidus, and phase transitions of the alloys along the Pd–In50Sn50 line were measured using DTA/DSC. Thermodynamic calculation of the In–Pd–Sn ternary system is performed using the CALPHAD method using the Thermo-Calc® software. The thermodynamic properties of the disordered fcc and liquid phases were described by the Redlich–Kister–Muggianu model. To describe intermetallic phases, namely, InPd3, Pd3Sn, τ1 and Pd2(InxSn1−x), a two-sublattice models was used. Thermodynamic description of the In–Pd–Sn system obtained in this study is in good agreement both with our results and the published experimental data
Journal Article
A Pilot Study of Changes in the Level of Catecholamines and the Activity of α-2-Macroglobulin in the Tear Fluid of Patients with Parkinson’s Disease and Parkinsonian Mice
2021
Development of differential and early (preclinical) diagnostics of Parkinson’s disease (PD) is among the priorities in neuroscience. We searched for changes in the level of catecholamines and α-2-macroglobulin activity in the tear fluid (TF) in PD patients at an early clinical stage. It was shown that TF in patients is characterized by an increased level of noradrenaline mainly on the ipsilateral side of pronounced motor symptoms (72%, p = 0.049), a decreased level of adrenaline on both sides (ipsilateral—53%, p = 0.004; contralateral—42%, p = 0.02), and an increased α-2-macroglobulin activity on both sides (ipsilateral—53%, p = 0.03; contralateral—56%, p = 0.037) compared to controls. These changes are considered as potential biomarkers for differential diagnosis. Similar changes in the TF were found in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice when modeling clinical and preclinical stages of PD. These data show the adequacy of models to the pathogenesis of PD along the selected metabolic pathways, and also suggest that the found TF changes can be considered as potential biomarkers for preclinical diagnosis of PD. In Parkinsonian mice, the level of catecholamines also changes in the lacrimal glands, which makes it possible to consider them as one of the sources of catecholamines in the TF.
Journal Article
Phase Equilibria in the Au-Cu-In-Pd System at 500 °C and 800 °C: Experimental Study and Modeling
by
Kareva, Maria A.
,
Ptashkina, Evgeniya A.
,
Kuznetsov, Victor N.
in
Ceramics
,
Composites
,
Copper
2024
Phase equilibria in the Pd rich region of the Au-Cu-In-Pd quaternary at 500 °C and 800 °C are investigated by SEM, EDX and XRD techniques. Part of the isothermal tetrahedron was constructed accounting for published data for bounding ternaries obtained earlier by the present authors. No quaternary phases were detected. The solubility of copper in the
τ
1
phase of the Au-In-Pd ternary (AuCu
3
structural type) does not exceed 5 at.%. Gold solubility in the InPd
2
Cu phase of the Cu-In-Pd ternary is not less than 18 at.% at 500 °C, and at least 15 at.% at 800 °C. Analytical description of the boundaries of the FCC solid solutions in the equilibrium with the InPd
3
, InPd
2
Cu and ternary
τ
1
phase was performed for bounding Cu-In-Pd and Au-In-Pd ternaries as well as for the quaternary. The tie-lines of the equilibria, i.e. the compositions of the two phases in equilibrium, were described as a single entity. To this end, the approach used in the literature for regression analysis of phase compositions of the (
γ
+
γ
′) Ni based superalloys was modified. The parametric descriptions of the two-phase tie-lines’ centers and those of the distribution coefficients of the components between the phases were built. The choice of parametrization is discussed. In particular cases of the ternaries and quaternary studied using the content of one or two of the components as parameters proved to be quite satisfactory. Very good description of the solubility lines and solubility surface including rather fine details has been achieved.Please check and confirm the edit made in the article title.Ok
Journal Article
On the features of diffusion combustion of hydrogen microjets
2024
This paper presents the results of an experimental investigation of the diffusion combustion scenario of a round hydrogen microjet flowing from a cylindrical thin-walled micronozzle with a diameter of 200 μm when ignited near and at any distance from the nozzle exit. A review of the literature on the research topic is presented and a comparison is performed in dimensionless parameters based on the Reynolds number. It has been established that stabilization of the torch during the expiration of a round microjet of hydrogen is associated with heating of the nozzle by the laminar region of the flame. A hysteresis of the process of diffusion combustion of round hydrogen microjets was discovered depending on the region of ignition of the microjet (laminar or turbulent region of the torch) and on changes in the jet velocity.
Journal Article
Ecotourism as an effective direction for a healthy lifestyle
2024
Ecotourism is one of the effective ways to ensure a healthy lifestyle. The paper is devoted to the study of the possibilities of developing ecotourism at the Crimean resorts in the northern Black Sea region of Russia. Today, eco-tourism is becoming increasingly popular. Every year more people are looking for outdoor recreation, away from noisy cities and all-inclusive hotels. This paper also substantiates the idea that ecotourism in Crimea is not only an opportunity to enjoy the natural beauty of the peninsula, but also to gain new emotions and impressions. Crimea is a unique region where you can visit the mountains, the sea coast, steppe plains or virgin forests. Such a variety of landscapes makes it possible to create eco-tourism programs that find their admirers. Accommodation in eco-estates is another option for those who want to relax in nature. Some of them offer truly unusual living conditions, for example, in artificial caves, where there is everything you need for a comfortable stay.
Journal Article
Using DTA/DSC data for assessment of the Toop and Muggianu predictive models for the Ag–Au–In ternary
by
Kuznetsov, Victor N.
,
Kabanova, Elizaveta G.
,
Khoroshilov, Andrey V.
in
Analysis
,
Analytical Chemistry
,
Chemistry
2019
The relative performance of the Muggianu and Toop methods of preliminary prediction of thermodynamic properties of solution phases is tested using Ag–Au–In ternary as a model system, which was recently studied by the present authors. The temperatures of solids, monovariant reaction (where appropriate) and liquids, as well as the heat of melting of solid solutions, were measured by DTA/DSC for five ternary samples. Different extrapolation models generate very different descriptions of phase equilibria. However, accounting for ternary interactions brings all the results into moderately close agreement. In both methods, the values of ternary parameters for liquid phase are more negative than for solid phases (about twice in modulo in Muggianu one and up to ten times in Toop case). This implies the stabilization of liquid in central concentration region. Neither predictive model captures this without accounting for ternary interactions.
Journal Article
Dynamic properties of reactor steels Kh16N15M3T1 and Kh13V2 under shock-wave loading of submicrosecond scale
by
Mokrushin, Sergey S.
,
Pavlenko, Alexander V.
,
Mayorova, Anna S.
in
Elastic limit
,
Light gas guns
,
Metallography
2018
Kh16N15M3T1 and Kh13V2 reactor steels were investigated. The study was carried out using a light-gas gun with the deformation velocities ranging from 4·10 4 to 3·10 6 s -1 and shock-loading pulses in 0.05-1 μs duration range. Dependences of the spallation strength and dynamic elastic limit in a wide temperature range are obtained. The recovered specimens were used to carry out the metallography analysis.
Journal Article