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21.
V. I. Kharuk I. A. Petrov M. L. Dvinskaya S. T. Im A. S. Shushpanov 《Contemporary Problems of Ecology》2018,11(4):388-395
The influence of climate changes on larch (Larix sibirica Ledeb.) radial increment under conditions of a limited (forest steppe) and sufficient (high-altitude Kuznetsk Alatau, floodplain stands) humidification is considered. The relationship between growth index of larch trees (N = 257) and ecological and climatic variables is analyzed. In the forest steppe, with the onset of warming, a decrease in the aridity of the climate, an increase in the duration of the growing season (1980s), and an increase in the larch growth index followed by its depression in the 1990s have been observed. Radial-increment depression is caused by an increase in vapor-pressure deficit and arid climate due to a rising air temperature. In the 2000s, radial-increment fluctuations with average values not exceeding those before the beginning of current climate warming period occurred. In the highlands, since the 1970s, there has been a general increase in the larch radial increment closely associated with the main limiting factor of growth—air temperature. At the same time, in arid years, the radial-increment depression of larch trees in highland and floodplain larch forests is also noted. When implementing “hard” climate scenarios (RCP 6.0 and RCP 8.5), it is likely that the larch growth index in a forest steppe will decrease further and its increase in areas of sufficient moisture will be observed. 相似文献
22.
The dynamics of meteorological parameters in Siberia and the Altai–Sayan region in the 20th–21st centuries are analyzed. Significant trends characterizing the dynamics of the average temperature, precipitation, and standardized precipitation evapotranspiration index (SPEI) are revealed. Growing wildfire frequency in the area under study since the end of the 20th century has been detected. The annual variation of wildfires has a phase coincidence with the dynamics of mean temperatures, positively correlates with climate dryness, and negatively correlates with averaged precipitation data. An abrupt increase in wildfire frequency has been observed in the late 20th–early 21st centuries. The spatial redistribution of wildfires in the Altai–Sayan region in the early 21st century is revealed. 相似文献
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24.
Neustroev KN Golubev AM Sinnott ML Borriss R Krah M Brumer H Eneyskaya EV Shishlyannikov S Shabalin KA Peshechonov VT Korolev VG Kulminskaya AA 《Glycoconjugate journal》2006,23(7-8):501-511
Comparative studies of the transglycosylation and hydrolytic activities have been performed on the Rhodothermus marinus β-1,3-glucanase (laminarinase) and its M133A, M133C, and M133W mutants. The M133C mutant demonstrated near 20% greater rate
of transglycosylation activity in comparison with the M133A and M133W mutants that was measured by NMR quantitation of nascent
β(1-4) and β(1-6) linkages. To obtain kinetic probes for the wild-type enzyme and Met-133 mutants, p-nitrophenyl β-laminarin oligosaccharides of degree of polymerisation 2–8 were synthesized enzymatically. Catalytic efficiency
values, k
cat/K
m, of the laminarinase catalysed hydrolysis of these oligosaccharides suggested possibility of four negative and at least three
positive binding subsites in the active site. Comparison of action patterns of the wild-type and M133C mutant in the hydrolysis
of the p-nitrophenyl-β-D-oligosac- charides indicated that the increased transglycosylation activity of the M133C mutant did not result
from altered subsite affinities. The stereospecificity of the transglycosylation reaction also was unchanged in all mutants;
the major transglycosylation products in hydrolysis of p-nitrophenyl laminaribioside were β-glucopyranosyl-β-1,3-D-glucopy- ranosyl-β-1,3-D-glucopyranose and β-glucopyranosyl-β-1,
3-D-glucopyranosyl-β-1,3-D-glucpyranosyl-β-1,3-D- glucopyranoxside.
In a memoriam of Dr. Kirill N. Neustroev. All we, his friends and colleagues, mourn for his sudden death. He was a bright
and talented scientist, brilliant manager and good friend. 相似文献
25.
Vera Malysheva Viacheslav Spirin Otto Miettinen Viviana Motato-Vásquez Hernawati Jaya Seelan Sathiya Seelan Karl-Henrik Larsson 《Mycological Progress》2018,17(7):805-814
Three species currently addressed to Protohydnum (Auriculariales) are studied with morphological and DNA methods. The genus Protohydnum is retained for the type species only, P. cartilagineum, recently re-collected in Brazil. The European species, P. piceicola, is not congeneric with P. cartilagineum and, therefore, placed in its own genus, Hyalodon, gen. nov. Another Hyalodon species, H. antui, is described from East Asia. The third member of Protohydnum sensu lato, P. sclerodontium from South-East Asia, is transferred to Elmerina. 相似文献
26.
As shown by morphological and molecular (ITS, nrLSU and tef1 sequences) evidence, the current concept of Myxarium nucleatum covers four species in the Nordic countries: M. cinnamomescens, M. hyalinum, M. nucleatum s.s. and M. populinum. These species are redescribed here, their nomenclature is discussed and all relevant names are typified. Exidia cartilaginea and E. villosa are typified and shown to be conspecific with the North American species E. candida. Based on morphological differences, E. cartilaginea is retained as a variety of E. candida. Exidia subrepanda is treated as a synomym of E. saccharina, and Heterochaete europaea as a synomym of E. thuretiana. 相似文献
27.
Landa LR Harbeck M Kaihara K Chepurny O Kitiphongspattana K Graf O Nikolaev VO Lohse MJ Holz GG Roe MW 《The Journal of biological chemistry》2005,280(35):31294-31302
Ca2+ and cAMP are important second messengers that regulate multiple cellular processes. Although previous studies have suggested direct interactions between Ca2+ and cAMP signaling pathways, the underlying mechanisms remain unresolved. In particular, direct evidence for Ca2+-regulated cAMP production in living cells is incomplete. Genetically encoded fluorescence resonance energy transfer-based biosensors have made possible real-time imaging of spatial and temporal gradients of intracellular cAMP concentration in single living cells. Here, we used confocal microscopy, fluorescence resonance energy transfer, and insulin-secreting MIN6 cells expressing Epac1-camps, a biosynthetic unimolecular cAMP indicator, to better understand the role of intracellular Ca2+ in cAMP production. We report that depolarization with high external K+, tolbutamide, or glucose caused a rapid increase in cAMP that was dependent on extracellular Ca2+ and inhibited by nitrendipine, a Ca2+ channel blocker, or 2',5'-dideoxyadenosine, a P-site antagonist of transmembrane adenylate cyclases. Stimulation of MIN6 cells with glucose in the presence of tetraethylammonium chloride generated concomitant Ca2+ and cAMP oscillations that were abolished in the absence of extracellular Ca2+ and blocked by 2',5'-dideoxyadenosine or 3-isobutyl-1-methylxanthine, an inhibitor of phosphodiesterase. Simultaneous measurements of Ca2+ and cAMP concentrations with Fura-2 and Epac1-camps, respectively, revealed a close temporal and causal interrelationship between the increases in cytoplasmic Ca2+ and cAMP levels following membrane depolarization. These findings indicate highly coordinated interplay between Ca2+ and cAMP signaling in electrically excitable endocrine cells and suggest that Ca2+-dependent cAMP oscillations are derived from an increase in adenylate cyclase activity and periodic activation and inactivation of cAMP-hydrolyzing phosphodiesterase. 相似文献
28.
Genetic and biochemical determinants of abnormal monovalent ion transport in primary hypertension 总被引:6,自引:0,他引:6
Orlov Sergei N.; Adragna Norma C.; Adarichev Viacheslav A.; Hamet Pavel 《American journal of physiology. Cell physiology》1999,276(3):C511
Data obtainedduring the last two decades show that spontaneously hypertensive rats,an acceptable experimental model of primary human hypertension, possessincreased activity of both ubiquitous and renal cell-specific isoformsof theNa+/H+exchanger (NHE) andNa+-K+-2Clcotransporter. Abnormalities of these ion transporters have been foundin patients suffering from essential hypertension. Recent geneticstudies demonstrate that genes encoding the - and -subunits ofENaC, a renal cell-specific isoform of theNa+-K+-2Clcotransporter, and 3-, 1-, and 2-subunits of theNa+-K+pump are localized within quantitative trait loci (QTL) for elevated blood pressure as well as for enhanced heart-to-body weight ratio, proteinuria, phosphate excretion, and stroke latency. On the basis ofthe homology of genome maps, several other genes encoding these transporters, as well as theNa+/H+exchanger andNa+-K+-2Clcotransporter, can be predicted in QTL related to the pathogenesis ofhypertension. However, despite their location within QTL, analysis ofcDNA structure did not reveal any mutation in the coding region of theabove-listed transporters in primary hypertension, with the exceptionof G276L substitution in the1-Na+-K+pump from Dahl salt-sensitive rats and a higher occurrence of T594Mmutation of -ENaC in the black population with essential hypertension. These results suggest that, in contrast to Mendelian forms of hypertension, the altered activity of monovalent ion transporters in primary hypertension is caused by abnormalities ofsystems involved in the regulation of their expression and/or function.Further analysis of QTL in F2hybrids of normotensive and hypertensive rats and in affected siblingpairs will allow mapping of genes causing abnormalities ofthese regulatory pathways. 相似文献
29.
Nikolaev VO Hoffmann C Bünemann M Lohse MJ Vilardaga JP 《The Journal of biological chemistry》2006,281(34):24506-24511
To characterize the mechanism by which heterotrimeric G-proteins interpret the signals coming from various neurotransmitters of diverse efficacies (agonists and partial agonists) acting on alpha(2A)-adrenergic receptors, we used a fluorescent resonance energy transfer-based approach to study the effects of these partial agonists on the activation process of both the alpha(2A)-adrenergic receptor and its cognate G(i)-protein. We show that ligands of different efficacies switch the receptor into distinct conformational states, which in turn set the speed and extent of the G(i)-protein signaling. Thus, in cells the efficacy by which a receptor responds to diverse ligands is caused by the ability of the G-protein to differentiate between distinct receptor conformations. The data provide a new key characteristic underlying the mechanism of partial agonism at G-protein-coupled receptors. 相似文献
30.
Siti H. Sheikh Abdul Kadir Michele Miragoli Shadi Abu-Hayyeh Alexey V. Moshkov Qilian Xie Verena Keitel Viacheslav O. Nikolaev Catherine Williamson Julia Gorelik 《PloS one》2010,5(3)