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881.
Yu-Wei Wu Xiaofang Tang Misa Arizono Hiroko Bannai Pei-Yu Shih Yulia Dembitskaya Victor Kazantsev Mika Tanaka Shigeyoshi Itohara Katsuhiko Mikoshiba Alexey Semyanov 《Cell calcium》2014
Astrocytes produce a complex repertoire of Ca2+ events that coordinate their major functions. The principle of Ca2+ events integration in astrocytes, however, is unknown. Here we analyze whole Ca2+ events, which were defined as spatiotemporally interconnected transient Ca2+ increases. Using such analysis in single hippocampal astrocytes in culture and in slices we found that spreads and durations of Ca2+ events follow power law distributions, a fingerprint of scale-free systems. A mathematical model demonstrated that such Ca2+ dynamics can arise from intracellular inositol-3-phosphate diffusion. The power law exponent (α) was decreased by activation of metabotropic glutamate receptors (mGluRs) either by specific receptor agonist or by low frequency stimulation of glutamatergic fibers in hippocampal slices. Decrease in α indicated an increase in proportion of large Ca2+ events. Notably, mGluRs activation did not increase the frequency of whole Ca2+ events. This result suggests that neuronal activity does not trigger new Ca2+ events in astrocytes (detectable by our methods), but modulates the properties of existing ones. Thus, our results provide a new perspective on how astrocyte responds to neuronal activity by changing its Ca2+ dynamics, which might further affect local network by triggering release of gliotransmitters and by modulating local blood flow. 相似文献
882.
Margarita G. Skalnaya Alexey A. Tinkov Vasily A. Demidov Eugeny P. Serebryansky Alexandr A. Nikonorov Anatoly V. Skalny 《Biological trace element research》2014,161(1):13-19
The primary objective of the current study was to estimate the hair toxic metal content in adults in relation to body mass index. A total of 1,229 persons including 719 women and 510 men were examined. All subjects were divided into two age groups: 1 and 2 periods of adulthood. All men and women were also subdivided into groups in relation to their values of body mass index (BMI): underweight, normal weight, overweight and obese. Hair aluminium (Al), beryllium (Be), cadmium (Cd), mercury (Hg), lead (Pb) and tin (Sn) content was evaluated using mass spectrometry with inductively coupled plasma. It has been shown that increase in body weight is accompanied by elevated hair cadmium content in women. At the same time, no significant alteration of hair cadmium concentration was observed in males. Higher values of scalp hair mercury and lead content were observed in men and women with increased body mass index independently of their age. BMI-related elevation of hair tin content was registered only in men of the first period of adulthood. A significant correlation between hair metal content and the values of BMI was observed for mercury independently of the gender of the subjects, whereas BMI values correlated significantly with hair cadmium levels in women and lead and tin levels in men. It has been also estimated that hair cadmium, mercury and lead levels in men exceed the respective values in women. 相似文献
883.
Nikolay?P. Kutuzov Alexey?R. Brazhe Georgy?V. Maksimov Olga?E. Dracheva Vladimir?L. Lyaskovskiy Fedor?V. Bulygin Andrey?B. Rubin 《Biophysical journal》2014,107(4):891-900
We study orientational ordering of membrane compounds in the myelinated nerve fiber by means of polarized Raman microspectroscopy. The theory of orientational distribution functions was adapted to live-cell measurements. The obtained orientational distribution functions of carotenoids and lipid acyl chain clearly indicated a predominantly radial-like orientation in membranes of the myelin. Two-dimensional Raman images, made under optimal polarization of incident laser beam, corroborated the proposed carotenoid orientation within the bilayer. Experimental data suggested the tilted orientation of both carotenoid polyenic and lipid acyl chains. The values of maximum tilt angles were similar, with possible implication of carotenoid-induced ordering effect on lipid acyl chains, and hence change of myelin membrane properties. This study stages carotenoids of the nerve as possible mediators of excitation and leverages underlying activity-dependent membrane reordering. 相似文献
884.
Jason N. MacTaggart Nicholas Y. Phillips Carol S. Lomneth Iraklis I. Pipinos Robert Bowen B. Timothy Baxter Jason Johanning G. Matthew Longo Anastasia S. Desyatova Michael J. Moulton Yuris A. Dzenis Alexey V. Kamenskiy 《Journal of biomechanics》2014
High failure rates of femoropopliteal artery reconstruction are commonly attributed to complex 3D arterial deformations that occur with limb movement. The purpose of this study was to develop a method for accurate assessment of these deformations. Custom-made stainless-steel markers were deployed into 5 in situ cadaveric femoropopliteal arteries using fluoroscopy. Thin-section CT images were acquired with each limb in the straight and acutely bent states. Image segmentation and 3D reconstruction allowed comparison of the relative locations of each intra-arterial marker position for determination of the artery’s bending, torsion and axial compression. After imaging, each artery was excised for histological analysis using Verhoeff–Van Gieson staining. Femoropopliteal arteries deformed non-uniformly with highly localized deformations in the proximal superficial femoral artery, and between the adductor hiatus and distal popliteal artery. The largest bending (11±3–6±1 mm radius of curvature), twisting (28±9–77±27°/cm) and axial compression (19±10–30±8%) were registered at the adductor hiatus and the below knee popliteal artery. These deformations were 3.7, 19 and 2.5 fold more severe than values currently reported in the literature. Histology demonstrated a distinct sub-adventitial layer of longitudinally oriented elastin fibers with intimal thickening in the segments with the largest deformations. This endovascular intra-arterial marker technique can quantify the non-uniform 3D deformations of the femoropopliteal artery during knee flexion without disturbing surrounding structures. We demonstrate that 3D arterial bending, torsion and compression in the flexed lower limb are highly localized and are substantially more severe than previously reported. 相似文献
885.
Mikhail Baboshin Tanya Ivashina Alexey Chernykh Ludmila Golovleva 《Biodegradation》2014,25(5):693-703
The genes of two ring-hydroxylating dioxygenases (RHDs) of Sphingomonas sp. VKM B-2434 were cloned and expressed in Escherichia coli. The relative values of the RHD specificity constants were estimated for six polycyclic aromatic hydrocarbons (PAHs) based on the kinetics of PAH mixture conversion by the recombinant strains. The substrate specificity profiles of the enzymes were found to be very different. Dioxygenase ArhA was the most specific to acenaphthylene and showed a low specificity to fluoranthene. Dioxygenase PhnA was the most specific to anthracene and phenanthrene and showed a considerable specificity to fluoranthene. Knockout derivatives of Sphingomonas sp. VKM B-2434 lacking ArhA, PhnA, and both dioxygenases were constructed. PAH degradation by the single-knockout mutants was in agreement with the substrate specificity of the RHD remaining intact. Double-knockout mutant lacking both enzymes was unable to oxidize PAHs. A mutant form of dioxygenase ArhA with altered substrate specificity was described. 相似文献
886.
887.
888.
Jinquan Luo Alexey Teplyakov Galina Obmolova Thomas J. Malia Winnie Chan Steven A. Jacobs Karyn T. O'Neil Gary L. Gilliland 《Proteins》2014,82(7):1527-1533
The crystal structure of an N‐terminal β‐strand‐swapped consensus‐derived tenascin FN3 alternative scaffold has been determined. A comparison with the unswapped structure reveals that the side chain of residue F88 orients differently and packs more tightly with the hydrophobic core of the domain. Dimer formation also results in the burial of a hydrophobic patch on the surface of the domain. Thus, it appears that tighter packing of F88 in the hydrophobic core and burial of surface hydrophobicity provide the driving forces for the N‐terminal β‐strand swapping, leading to the formation of a stable compact dimer. Proteins 2014; 82:1527–1533. © 2014 Wiley Periodicals, Inc. 相似文献
889.
Aaron Moulin Magali Mathieu Catherine Lawrence Russell Bigelow Mark Levine Christine Hamel Jean‐Piere Marquette Josiane Le Parc Christophe Loux Paul Ferrari Cecile Capdevila Jacques Dumas Bruno Dumas Alexey Rak Julie Bird Huawei Qiu Clark Q. Pan Tim Edmunds Ronnie R. Wei 《Protein science : a publication of the Protein Society》2014,23(12):1698-1707
Various important biological pathways are modulated by TGFβ isoforms; as such they are potential targets for therapeutic intervention. Fresolimumab, also known as GC1008, is a pan‐TGFβ neutralizing antibody that has been tested clinically for several indications including an ongoing trial for focal segmental glomerulosclerosis. The structure of the antigen‐binding fragment of fresolimumab (GC1008 Fab) in complex with TGFβ3 has been reported previously, but the structural capacity of fresolimumab to accommodate tight interactions with TGFβ1 and TGFβ2 was insufficiently understood. We report the crystal structure of the single‐chain variable fragment of fresolimumab (GC1008 scFv) in complex with target TGFβ1 to a resolution of 3.00 Å and the crystal structure of GC1008 Fab in complex with TGFβ2 to 2.83 Å. The structures provide further insight into the details of TGFβ recognition by fresolimumab, give a clear indication of the determinants of fresolimumab pan‐specificity and provide potential starting points for the development of isoform‐specific antibodies using a fresolimumab scaffold. 相似文献
890.
Konstantin N. Belosludtsev Natalia V. Belosludtseva Maxim S. Kondratyev Alexey V. Agafonov Yuriy A. Purtov 《The Journal of membrane biology》2014,247(3):281-288
Phospholipase A of the bacterial outer membrane (OMPLA) is a β-barrel membrane protein which is activated under various stress conditions. The current study examines interaction of inhibitors of eucaryotic phospholipases A2—palmitoyl trifluoromethyl ketone (PACOCF3) and aristolochic acid (AA)—with OMPLA and considers a possible involvement of the enzyme in the Ca2+-dependent permeabilization of the outer membrane of Escherichia coli. Using the method of molecular docking, it has been predicted that PACOCF3 and AA bind to OMPLA at the same site and with the same affinity as the OMPLA inhibitors, hexadecanesulfonylfluoride and bromophenacyl bromide, and the substrate of the enzyme palmitoyl oleoyl phosphatidylethanolamine. It has also been shown that PACOCF3, AA, and bromophenacyl bromide inhibit the Ca2+-induced temperature-dependent changes in the permeability of the bacterial membrane for the fluorescent probe propidium iodide and suppressed the transformation of E. coli cells with plasmid DNA induced by Ca2+ and heat shock. The cell viability was not affected by the eucaryotic phospholipases A2 inhibitors. The study discusses a possible involvement of OMPLA in the mechanisms of bacterial transmembrane transport based on the permeabilization of the bacterial outer membrane. 相似文献