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Shtyrlin Valery G. Borissenok Valery A. Serov Nikita Yu. Simakov Vladimir G. Bragunets Vyacheslav A. Trunin Ivan R. Tereshkina Irina A. Koshkin Sergey A. Bukharov Mikhail S. Gilyazetdinov Edward M. Shestakov Evgeny E. Sirotkina Anna G. Zakharov Alexey V. 《Origins of life and evolution of the biosphere》2019,49(1-2):1-18
Origins of Life and Evolution of Biospheres - Syntheses under shock in nitrogen bubbled samples of the water – formamide – bicarbonate – sodium hydroxide system at... 相似文献
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Sergiev PV Lesnyak DV Burakovsky DE Svetlov M Kolb VA Serebryakova MV Demina IA Govorun VM Dontsova OA Bogdanov AA 《Journal of molecular biology》2012,416(5):656-667
Catalysis of peptide bond formation in the peptidyl transferase center is a major enzymatic activity of the ribosome. Mutations limiting peptidyl transferase activity are mostly lethal. However, cellular processes triggered by peptidyl transferase deficiency in the bacterial cell are largely unknown. Here we report a study of the lethal G2061C mutant of Escherichia coli 23S ribosomal RNA (rRNA). The G2061C mutation completely impaired the puromycin reaction and abolished formation of the active firefly luciferase in an in vitro translation system, while poly(U)- and short synthetic mRNA-directed peptidyl transferase reaction with aminoacylated tRNAs in vitro was seemingly unaffected. Study of the cellular proteome upon expression of the 23S rRNA gene carrying the G2061C mutation compared to cells expressing wild-type 23S rRNA gene revealed substantial differences. Most of the observed effects in the mutant were associated with reduced expression of stress response proteins and particularly proteins associated with the ppGpp-mediated stringent response. 相似文献
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Waterbugs (Heteroptera: Nepomorpha and Gerromorpha) as sources of essential n‐3 polyunsaturated fatty acids in Central Siberian ecoregions 下载免费PDF全文
Nadezhda N. Sushchik Yuri A. Yurchenko Olga E. Belevich Galina S. Kalachova Anzhelika A. Kolmakova Michail I. Gladyshev 《Freshwater Biology》2016,61(10):1787-1801
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Vyacheslav?A.?Shmarov Vladimir?V.?Malashchenko Maksim?E.?Meniailo Natalia?D.?Gazatova Natalia?M.?Todosenko Olga?B.?Melashchenko Andrei?G.?Goncharov Victor?I.?SeledtsovEmail author 《European cytokine network》2016,27(4):102-107
CD3+ T lymphocytes were isolated by positive magnetic separation from the peripheral blood of healthy donors. In the absence of any additional activating stimuli, interleukin-7 (IL-7) was shown to augment the levels of T cells expressing CD25 activation marker both in CD4-positive and in CD4-negative effector memory (CD45RA-CD197-) T cell subsets, as well as in terminally differentiated (CD45RA+CD197-) T cells, without significantly affecting the activation status of naive (CD45RA+CD197+) and central memory (CD45RA-CD197+) T cells. In addition, IL-7 noticeably enhanced the production of IL-2, interferon-γ (IFN-γ), and IL-10, but not IL-4, in T cells. The direct effects of IL-7 on T cell activation induced in vitro by MACSiBead? particles coated with CD2, CD3, and CD28 antibodies (Abs) were also investigated. Upon cell activation, IL-7 significantly augmented the levels of CD25+ T cells in naive (CD45RA+CD197+), central memory (CD45RA-CD197+), and effector memory (CD45RA-CD197-) T-cell compartments. In addition, IL-7 facilitated activation of CD4- (but not CD4+) terminally differentiated effector (CD45RA+CD197-) T cells. Finally, IL-7 was found to upregulate the production of IL-2, IFN-γ, IL-4, and IL-10 by activated T cells. In conclusion, we speculate that IL-7 is capable of enhancing functional T cell activity without causing significant functional inbalance between various T cell subsets. 相似文献
17.
Late Pleistocene origin of the entire circumarctic range of the arctic‐alpine plant Kalmia procumbens 下载免费PDF全文
Hajime Ikeda Pernille Bronken Eidesen Valentin Yakubov Vyacheslav Barkalov Christian Brochmann Hiroaki Setoguchi 《Molecular ecology》2017,26(20):5773-5783
The circumarctic ranges of arctic‐alpine plants are thought to have been established in the late Pliocene/early Pleistocene, when the modern arctic tundra was formed in response to climate cooling. Previous findings of range‐wide genetic structure in arctic‐alpine plants have been thought to support this hypothesis, but few studies have explicitly addressed the temporal framework of the genetic structure. Here, we estimated the demographic history of the genetic structure in the circumarctic Kalmia procumbens using sequences of multiple nuclear loci and examined whether its genetic structure reflects prolonged isolation throughout the Pleistocene. Both Bayesian clustering and phylogenetic analyses revealed genetic distinction between alpine and arctic regions, whereas detailed groupings were somewhat discordant between the analyses. By assuming a population grouping based on the phylogenetic analyses, which likely reflects a deeper intraspecific divergence, we conducted model‐based analyses and demonstrated that the intraspecific genetic divergence in K. procumbens likely originated during the last glacial period. Thus, there is no need to postulate range separation throughout the Pleistocene to explain the current genetic structure in this species. This study demonstrates that range‐wide genetic structure in arctic‐alpine plants does not necessarily result from the late Pliocene/early Pleistocene origin of their circumarctic ranges and emphasizes the importance of a temporal framework of the current genetic structure for understanding the biogeographic history of the arctic flora. 相似文献
18.
The density of the noninductive current generated due to collisionless motion of α-particles in the tokamak magnetic field is calculated. The analysis is based on fully three-dimensional calculations of charged particle trajectories without simplifying assumptions typical for drift and neoclassical approaches. The current is calculated over the entire cross section of the plasma column, including the magnetic axis. It is shown that the current density is not a function of a magnetic surface and is strongly polarized over the poloidal angle. The current density distribution in the tokamak poloidal cross section is obtained, and the current density as a function of the safety factor, the tokamak aspect ratio, and the ratio of the particle Larmor radius on the axis to the tokamak minor radius is determined. It is shown that, when the source of α-particles is spatially nonuniform, the current density in the center of the tokamak is nonzero due to asymmetry of the phase-space boundary between trapped and passing particles. The current density scaling in the tokamak center differs from the known approximations for the bootstrap current and is sensitive to the spatial distribution of α-particles. 相似文献
19.
Oxygen consumption in Mn-depleted photosystem II (PSII) preparations under continuous and pulsed illumination is investigated. It is shown that removal of manganese from the water-oxidizing complex (WOC) by high pH treatment leads to a 6-fold increase in the rate of O2 photoconsumption. The use of exogenous electron acceptors and donors to PSII shows that in Mn-depleted PSII preparations along with the well-known effect of O2 photoreduction on the acceptor side of PSII, there is light-induced O2 consumption on the donor side of PSII (nearly 30% and 70%, respectively). It is suggested that the light-induced O2 uptake on the donor side of PSII is related to interaction of O2 with radicals produced by photooxidation of organic molecules. The study of flash-induced O2 uptake finds that removal of Mn from the WOC leads to O2 photoconsumption with maximum in the first flash, and its yield is comparable with the yield of O2 evolution on the third flash measured in the PSII samples before Mn removal. The flash-induced O2 uptake is drastically (by a factor of 1.8) activated by catalytic concentration (5-10 μM, corresponding to 2-4 Mn per RC) of Mn2+, while at higher concentrations (> 100 μM) Mn2+ inhibits the O2 photoconsumption (like other electron donors: ferrocyanide and diphenylcarbazide). Inhibitory pre-illumination of the Mn-depleted PSII preparations (resulting in the loss of electron donation from Mn2+) leads to both suppression of flash-induced O2 uptake and disappearance of the Mn-induced activation of the O2 photoconsumption. We assume that the light-induced O2 uptake in Mn-depleted PSII preparations may reflect not only the negative processes leading to photoinhibition but also possible participation of O2 or its reactive forms in the formation of the inorganic core of the WOC. 相似文献
20.
Veshkurova O Golubenko Z Pshenichnov E Arzanova I Uzbekov V Sultanova E Salikhov S Williams HJ Reibenspies JH Puckhaber LS Stipanovic RD 《Phytochemistry》2006,67(21):2376-2379
The isolation and structure of a phytoalexin, malvone A (2-methyl-3-methoxy-5,6-dihydroxy-1,4-naphthoquinone) is reported. Malvone A formation is induced in Malva sylvestris L. by the plant pathogen Verticillium dahliae. In a turbimetric assay for toxicity to V. dahliae, it had an ED50 value of 24 microg/ml. The structure of malvone A was determined by MS and NMR spectroscopy, and by X-ray crystallographic analysis. The X-ray analysis showed water molecules were located in channels that run along the a-axis. 相似文献