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41.
A prokaryotic condensin/cohesin-like complex can actively compact chromosomes from a single position on the nucleoid and binds to DNA as a ring-like structure 下载免费PDF全文
Volkov A Mascarenhas J Andrei-Selmer C Ulrich HD Graumann PL 《Molecular and cellular biology》2003,23(16):5638-5650
We show that Bacillus subtilis SMC (structural maintenance of chromosome protein) localizes to discrete foci in a cell cycle-dependent manner. Early in the cell cycle, SMC moves from the middle of the cell toward opposite cell poles in a rapid and dynamic manner and appears to interact with different regions on the chromosomes during the cell cycle. SMC colocalizes with its interacting partners, ScpA and ScpB, and the specific localization of SMC depends on both Scp proteins, showing that all three components of the SMC complex are required for proper localization. Cytological and biochemical experiments showed that dimeric ScpB stabilized the binding of ScpA to the SMC head domains. Purified SMC showed nonspecific binding to double-stranded DNA, independent of Scp proteins or ATP, and was retained on DNA after binding to closed DNA but not to linear DNA. The SMC head domains and hinge region did not show strong DNA binding activity, suggesting that the coiled-coil regions in SMC mediate an association with DNA and that SMC binds to DNA as a ring-like structure. The overproduction of SMC resulted in global chromosome compaction, while SMC was largely retained in bipolar foci, suggesting that the SMC complex forms condensation centers that actively affect global chromosome compaction from a defined position on the nucleoid. 相似文献
42.
The product of the SUP35 gene of the saccharomycete yeast, the translation termination eRF3 factor, can be converted in prion, the heritable determinant of protein nature. The nucleotide sequence of this gene from the strain belonging to Peterhof genetic lines of the yeast Saccharomyces cerevisiae was determined. A comparison of the identified sequence with SUP35 sequences in the database of GenBank allowed the detection of polymorphic sites both in the SUP35 gene and its product. The location of polymorphic sites in the evolutionarily nonconserved N-terminal protein region confirmed that this eRF3 fragment lacks functions vital to life activity. Nevertheless, these sites are located in the vicinity of sites, whose role in the prion conversion of eRF3 has been established. Based on this, natural polymorphism of the primary eRF3 structure is assumed to be connected with the existence of different variants (strains) of its prion analog. 相似文献
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V. V. Alikaev A. A. Borshchegovskii V. V. Volkov M. M. Dremin Yu. V. Esipchuk A. M. Kakurin N. A. Kirneva A. Ya. Kislov D. A. Kislov I. V. Klimanov V. A. Kochin V. A. Krupin S. V. Krylov T. B. Myalton A. Yu. Novikov G. E. Notkin Yu. D. Pavlov V. V. Piterskii V. I. Poznyak I. N. Roi P. V. Savrukhin M. M. Stepanenko A. V. Sushkov V. M. Trukhin E. V. Trukhina V. V. Chistyakov 《Plasma Physics Reports》2000,26(12):991-999
In T-10 experiments, attempts were made to significantly exceed the Greenwald limit $\bar n_{Gr} $ during high-power (P ab=750 kW) electron-cyclotron resonance heating (ECRH) and gas puffing. Formally, the density limit $(\bar n_e )_{\lim } $ exceeding the Greenwald limit $({{(\bar n_e )_{\lim } } \mathord{\left/ {\vphantom {{(\bar n_e )_{\lim } } {\bar n_{Gr} }}} \right. \kern-0em} {\bar n_{Gr} }} = 1.8)$ was achieved for q L=8.2. However, as q L decreased, the ratio ${{(\bar n_e )_{\lim } } \mathord{\left/ {\vphantom {{(\bar n_e )_{\lim } } {\bar n_{Gr} }}} \right. \kern-0em} {\bar n_{Gr} }}$ also decreased, approaching unity at q L≈3. It was suggested that the “current radius” (i.e., the radius of the magnetic surface enclosing the bulk of the plasma current I p), rather than the limiter radius, was the parameter governing the value of $(\bar n_e )_{\lim } $ . In the ECRH experiments, no substantial degradation of plasma confinement was observed up to $\bar n_e \sim 0.9(\bar n_e )_{\lim } $ regardless of the ratio ${{(\bar n_e )_{\lim } } \mathord{\left/ {\vphantom {{(\bar n_e )_{\lim } } {\bar n_{Gr} }}} \right. \kern-0em} {\bar n_{Gr} }}$ . In different scenarios of the density growth up to $(\bar n_e )_{\lim } $ , two types of disruptions related to the density limit were observed. 相似文献
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A phospholipid chelate complexed with ytterbium (DMPE-DTPA:Yb3+) is shown to be readily incorporated into a model membrane system, which may then be aligned in a magnetic field such that the average bilayer normal lies along the field. This so-called positively ordered smectic phase, whose lipids consist of less than 1% DMPE-DTPA:Yb3+, is ideally suited to structural studies of membrane proteins by solid-state NMR, low-angle diffraction, and spectroscopic techniques that require oriented samples. The chelate, 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine diethylenetriaminepentaacetic acid, which strongly binds the lanthanide ions and serves to orient the membrane in a magnetic field, prevents direct lanthanide-protein interactions and significantly reduces paramagnetic shifts and line broadening. Similar low-spin lanthanide chelates may have applications in field-ordered solution NMR studies of water-soluble proteins and in the design of new magnetically aligned liquid crystalline phases. 相似文献
46.
Shai Efrati Haim Golan Yair Bechor Yifat Faran Shir Daphna-Tekoah Gal Sekler Gregori Fishlev Jacob N. Ablin Jacob Bergan Olga Volkov Mony Friedman Eshel Ben-Jacob Dan Buskila 《PloS one》2015,10(5)
BackgroundFibromyalgia Syndrome (FMS) is a persistent and debilitating disorder estimated to impair the quality of life of 2–4% of the population, with 9:1 female-to-male incidence ratio. FMS is an important representative example of central nervous system sensitization and is associated with abnormal brain activity. Key symptoms include chronic widespread pain, allodynia and diffuse tenderness, along with fatigue and sleep disturbance. The syndrome is still elusive and refractory. The goal of this study was to evaluate the effect of hyperbaric oxygen therapy (HBOT) on symptoms and brain activity in FMS.ConclusionsThe study provides evidence that HBOT can improve the symptoms and life quality of FMS patients. Moreover, it shows that HBOT can induce neuroplasticity and significantly rectify abnormal brain activity in pain related areas of FMS patients.
Trial Registration
ClinicalTrials.gov NCT01827683相似文献47.
N M Gulaia G L Volkov V K Lishko N N Govseeva E P Klimenko 《Ukrainski? biokhimicheski? zhurnal》1986,58(1):44-48
The paper deals with functional characteristics of fast sodium channels modified by liposomes of differentiated neuroblastoma cells. Cells with a 60% increased total cholesterol content were used. The cells were found to contain lysolecithin. In lecithin the amount of polyunsaturated fatty acids was enhanced. It is established that veratrin added to the culture medium of cholesterol-enriched cells increased the rate of 86Rb release to a greater extent than in the control cells. When studying the temperature dependence of veratrin-activated transport of Rb+ in the intact and lecithin-cholesterol-lyposomes-modified cells it was shown that the veratrin-activated Rb+ release is more sensitive to temperature fluctuations than nonactivated one. In this case it is higher in lecithin-cholesterol-lyposomes-modified cells than in intact ones. 相似文献
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Volkov V Hachez C Moshelion M Draye X Chaumont F Fricke W 《Journal of experimental botany》2007,58(3):377-390
A pressure probe technique and an osmotic swelling assay were used to compare water transport properties between growing and non-growing tissues of leaf three of barley. The epidermis was analysed in planta by pressure probe, whereas (predominantly) mesophyll protoplasts were analysed by osmotic swelling. Hydraulic conductivity (Lp) and, by implication, water permeability (Pf) of epidermal cells was 31% higher in the leaf elongation zone (Lp=0.5+/-0.2 microm s-1 MPa-1; Pf=65+/-25 microm s-1; means+/-SD of n=17 cells) than in the, non-growing, emerged leaf zone (Lp=0.4+/-0.1 microm s-1 MPa-1; Pf=50+/-15 microm s-1; n=24; P<0.05). Similarly, water permeability of mesophyll protoplasts was by 55% higher in the elongation compared with emerged leaf zone (Pf=13+/-1 microm s-1 compared with 8+/-1 microm s-1; n=57 and 36 protoplasts, respectively; P<0.01). Within the leaf elongation zone, a small population of larger-sized protoplasts could be distinguished. These protoplasts, which originated most likely from parenchymateous bundle sheath or midrib parenchyma cells, had a three-fold higher water permeability (P<0.001) as mesophyll protoplasts. The effect on Lp and Pf of known aquaporin inhibitors was tested with the pressure probe (Au+, Ag+, Hg2+, phloretin) and the osmotic swelling assay (phloretin). Only phloretin, when applied to protoplasts in the swelling assay caused an average decrease in Pf, but the effect varied between isolations. Technical approaches and cell-type and growth-specific differences in water transport properties are discussed. 相似文献
50.
Knowledge of neural interactions amongst cortical sites is important for understanding higher brain function. We studied such interactions using Granger causality (GC) to analyze auditory event-related potentials (ERPs) recorded directly and simultaneously from two physiologically identified and functionally interconnected auditory areas of cerebral cortex in human neurosurgical patients. Two methods of GC analysis were used and the results compared. Both approaches involved adaptive autoregressive modeling but differed from each other in other ways. Results obtained by using the two methods also differed. Fewer false-positive results were obtained using the method that suppressed the ERP non-stationarity and that expressed the GC as the sum of model coefficients, which suggests that this is the more appropriate approach for analyzing ERPs recorded directly from the human cortex. 相似文献