Suchergebnisse

High-latitude terrestrial ecosystems are crucial to the global climate system and its regulation by vegetation. Since productivity of boreal forests is much limited by low summer temperatures, it is expected that trees subjected to warming are progressively decreasing their regional growth coherence in the last decades. In this study, we used a comprehensive network of indexed ring-width records to assess 20th-century spatiotemporal patterns of climatic sensitivity of forest growth around the Urals mountain range above 60 °N (ca. 750,000 km2). This area offers an excellent opportunity to test for warming effects as most north Eurasian conifers (including Larix, Picea and Pinus species) are found along a north-to-south temperature gradient across contrasting soil hydrothermal regimes (permafrost and permafrost-free). We observed positive associations between indexed ring-width and summer temperature over the past century, decreasing southwards. However, weaker (permafrost) or non-significant (permafrost-free) relationships were consistently found at the local and regional scales after 1960. A cointegration analysis indicated that tree-growth release from cold limitation significantly reduced the degree and spatial extent of synchronous growth at short- (annual) and long-term (decadal) scales, most likely by exposing forests to endogenous (local) factors (e.g., competition, soil properties, nutrient availability) and species-specific reactions. Whereas the loss of temperature sensitivity progressively reduced non-permafrost synchrony by 50% over the whole 20th century, permafrost forests decreased their synchrony only after the 1960s, by 20%. Radial growth was enhanced in permafrost sites, as suggested by increasing basal area increment. Our results unequivocally link a substantial decrease in temporal coherence of forest productivity in boreal ecosystems to a growth release from cold limitation that is concurrent with regional warming trends. This emerging pattern points to increasing dependence on local drivers of the carbon balance and the role as carbon sinks of forests in the northern Ural region. ; This study was funded by the European Union's Seventh Framework Programme (INTERACT project), grant agreement SYNCHROTREES, the Spanish Government (grant number AGL2015-68274-C3-3-R) and the Russian Science Foundation (project number 18-14-00072).

Quercetin (3,3ʹ,4ʹ,5,7-pentahydroxyflavon), one of the most common and studied flavonoids, possesses the antioxidant activity and demonstrates the pronounced therapeutic potential under a number of pathological conditions. The purpose of this work is to estimate the electronic structure of the quercetin and its semi-quinone radical molecules and to compare the antioxidant activities of quercetin and its inclusion complex with hydroxypropyl-β-cyclodextrin. Generation of maps of the electron density distribution in quercetin and quercetin semi-quinone radical molecules showed that the active electron orbitals (HOMO and LUMO) are delocalized over all phenolic rings providing the radical stabilization. We have showed that quercetin prevents the tert-butyl hydroperoxide-induced lipid peroxidation of erythrocytes (IC50= 25 ± 3 μM) and mitochondrial membranes (IC50= 31 ± 4 μM). The efficiency of quercetin inhibition the reduced glutathione oxidation in erythrocytes and mitochondria is much lower reflecting the lipophilicity of polyphenol. Quercetin also prevented the hypochlorite-induced lysis of red blood cells (IC50= 3 ± 0.5 μM). Our data revealed that the quercetin-hydroxypropyl-β-cyclodex-trin complex is more effective inhibitor of the membrane lipids peroxidation and glutathione oxidation processes.

Hypochlorous acid, HOCl, is one of the most powerful biological oxidants and the most important mediator of inflammatory damage of cells and tissues. The purpose of this study was to characterize the morphological features of HOCl – induced oxidative impairment in rat liver mitochondria in vitro and to compare the processes of HOCl-induced oxidation in mitochondria, erythrocytes and B14 cells.HOCl addition (300 μM) to mitochondrial suspension resulted in mitochondrial structural changes with a decrease in the mean total length of the crista and the average number of cristae in one mitochondria with no change in the length of one crista. There was shown a slight decrease in the average cross-sectional area of one mitochondria, mitochondrial profile elongation, an increase in the number of altered mitochondria and the heterogeneity of the population. Simultaneously we observed depolarization of the mitochondrial membrane, the rate and degree of which were determined by the concentration of HOCl. HOCl addition (25–150 μМ) induced lysis of erythrocytes for 60–180 s, which was preceded by a change in the shape and size of cells. The apparent dissociation constant for the HOCl – membrane complex was estimated to be Kd = 140 ± 25 μМ, and the Hill coefficient was to be 2.1. The B14 cell exposure to HOCl (100 μМ) led to a loss of ability to sorb on the substrate, to form associates, and to subsequent shrinkage of cells.Therefore, HOCl caused some morphological (and functional) changes in rat liver mitochondria, which may serve as one of the causes of cell death in inflammatory foci. At the level of the whole cells, the HOCl addition induced lysis of red blood cells and deep damage to B14 cells.

The article provides information about rare and newly described species for the flora of the Urals and adjacent territories, namely: Astragalus saphronovae Kulikov, Atraphaxis decipiens Jaub. et Spach., Carex amgunensis F. Schmidt, Galium densiflorum Ledeb., Jovibarba globifera (L.) J. Parn., Najas minor All., Potamogeton nodosus Poir., Pseudorchis albida (L.) Á. Löve et D. Löve, Salix myrsinites L., Veronica agrestis L. Essays include the information on the species ecology and short taxonomic notes. © 2021 Altai State University. All rights reserved. ; The work was supported by the state assignments: АААА-А19-119031290052-1 "Sosudistye rasteniia Evrazii: sistematika, flora, rastitelʹnye resursy" ["Vascular plants of Eurasia: systematics, flora, plant resources"], АААА-А18-118011990151-7 "Izucheniye, sokhraneniye i rasshireniye bioraznoobraziya rasteniy v prirode i pri introduktsii na Yuzh nom Urale i Priuralye" ["Study, conservation and expansion of plant biodiversity in nature and during introduction in the Southern Urals and the Cis- and Trans-Urals region"], AAAA-A17-117050400146-5 "Otsenka prostranstvennovremennoy izmenchivosti bioraznoobraziya i usloviy yego formirovaniya na Severe Zapadnoy Sibiri v svyazi s izmeneniyem klimata i osvoyeniyem neftegazovykh resursov" ["Assessment of the spatio-temporal variability of biodiversity and the conditions for its formation in the north of Western Siberia in connection with climate change and the development of oil and gas resources"], and by "Programmoy povysheniya konkurentosposobnosti Uralskogo federalnogo universiteta" ["The program for improving the competitiveness of the Ural Federal University"] (the decree no. 211 of the Government of the Russian Federation, contract no. 02.A03.21.0006).