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61.
R.?B.?AisinaEmail author L.?I.?Mukhametova K.?B.?Gershkovich V.?N.?Yakovlev E.?I.?Goufman N.?B.?Tikhonova 《Russian Journal of Bioorganic Chemistry》2018,44(2):210-216
A method of ELISA for measuring the binding of different samples of immunoglobulin (IgG) and its fragments to human plasminogen (Pg) has been developed. Instead of plasminogen, the heavy chain of plasminogen (Pg-H) containing five ligand-binding kringle domains, immobilized on the surface of the plate, was used in this method as a detector. It was found that IgG treated with plasmin (IgGPm-t) binds to the immobilized Pg-H 2.84 times more strongly than intact IgG. Both IgG samples showed a weak nonspecific binding to the immobilized light chain of plasminogen (Pg-L). It was shown that 0.2 M L-lysine inhibits the binding of IgGPm-t and does not affect the nonspecific binding of intact IgG to the immobilized Pg-H, indicating the involvement of lysine-binding regions of Pg-H in binding to IgGPm-t. A preliminary treatment of IgG samples with carboxypeptidase В (CPB) inhibited the binding of IgGPm-t and did not affect the nonspecific binding of intact IgG to the immobilized Pg-H, which indicates a key role of the С-terminal lysine of IgGPm-t in the specific binding to the lysine-binding sites of Pg. The study of the effects of intact IgG and IgGPm-t on the rate of activation of Glu- and Lys-forms of Pg (Glu-Pg and Lys-Pg) by a tissue activator of Pg (tPA) and urokinase (uPA) in buffer showed that intact IgG completely inhibited the activation of Glu-Pg and Lys-Pg with both tPA and uPA. Presumably, the inhibitory effect of intact IgG is due to steric hindrances that it creates for protein–protein interactions of the activators with the zymogen. IgGPm-t accelerated the generation of plasmin from Pg. In this case, the stimulatory effect of IgGPm-t on the activation of Glu-Pg under the action of tPA was ~25% higher than on the activation of Lys-Pg, which is explained by more significant conformational changes in the Glu-Pg molecule compared with the Lys-Pg molecule after their binding to IgGPm-t. The results suggest that the specific cleavage of IgG by plasmin may be one of the ways by which the plasminogen/plasmin system is involved in various physiological and pathological processes. 相似文献
62.
Dyspessa peri sp. n. (Lepidoptera: Cossidae) is described from Sarobi in Central Afghanistan. The new species is closely related to D. tristis A. Bang-Haas, 1912, and is distinguished by peculiarities of the wing pattern and structure of the male genitalia.
http://www.zoobank.org/urn:lsid:zoobank.org:pub:D58AAAC5-90F2-4D06-9DB2-C4D3CDE36265 相似文献
63.
Predicting Calendar Aging in Lithium Metal Secondary Batteries: The Impacts of Solid Electrolyte Interphase Composition and Stability
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Sean M. Wood Chengcheng Fang Eric J. Dufek Shrikant C. Nagpure Sergiy V. Sazhin Boryann Liaw Y. Shirley Meng 《Liver Transplantation》2018,8(26)
Calendar aging of lithium metal batteries, in which cells' components degrade internally due to chemical reactions while no current is being applied, is a relatively unstudied field. In this work, a model to predict calendar aging of lithium metal cells is developed using two sets of readily obtainable data: solid electrolyte interphase (SEI) layer composition (measured via X‐ray photoelectron spectroscopy) and SEI stability (measured as a degradation rate using a simple constant current–constant voltage charging protocol). Electrolyte properties such as volume and salt concentration are varied in order to determine their effect on SEI stability and composition, with subsequent impacts to calendar aging. Lower salt concentrations produce a solvent‐based, more soluble SEI, while the highest concentration produces a salt‐based, less soluble SEI. Higher electrolyte volumes promote dissolution of the SEI and thus decrease its stability. The model predicts that lithium metal would be the limiting factor in calendar aging, depleting long before the electrolyte does. Additionally, the relative composition of the electrolyte during aging is modeled and found to eventually converge to the same value independent of initial salt concentration. 相似文献
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65.
The shape of the plots of initial reaction rate (ν) versus initial substrate concentration ([S]0) and versus initial concentration of allosteric effector ([F]0) for the model of allosteric enzyme of Monod, Wyman &; Changeux (1965) and for the model of dissociating regulatory enzyme has been analysed by means of the inconstant exponent (q) for substrate or effector concentration, respectively. It has been shown that allosteric interactions in above-mentioned models with “indirect” co-operativity may be manifested not only by the sigmoidal shape of the plot of ν versus [S]0 or ν versus [F]0 (with one point of inflexion) but also by the increase in the magnitude of exponent q in progress of saturation process of the enzyme by the substrate or by the effector in the absence of the sigmoidal shape of these plots. It has been shown also that the plot of ν versus [S]0 has two inflexion points when the parameters have certain definite values. One of these inflexion points (or even both at definite values of the parameters) is hardly discernible. At certain definite values of the parameters two inflexion points may be kinetically manifested by such phenomenon as “negative” co-operativity (q < 1). This is possible if one of the interconvertable enzyme forms exceeds another not only in the affinity to the substrate but also in the value of the rate constant for catalytic breakdown of the enzyme-substrate complex. 相似文献
66.
Sergiy Tyukhtenko Ioannis Karageorgos Girija Rajarshi Nikolai Zvonok Spiro Pavlopoulos David R. Janero Alexandros Makriyannis 《The Journal of biological chemistry》2016,291(6):2556-2565
The serine hydrolase monoacylglycerol lipase (MGL) functions as the main metabolizing enzyme of 2-arachidonoyl glycerol, an endocannabinoid signaling lipid whose elevation through genetic or pharmacological MGL ablation exerts therapeutic effects in various preclinical disease models. To inform structure-based MGL inhibitor design, we report the direct NMR detection of a reversible equilibrium between active and inactive states of human MGL (hMGL) that is slow on the NMR time scale and can be modulated in a controlled manner by pH, temperature, and select point mutations. Kinetic measurements revealed that hMGL substrate turnover is rate-limited across this equilibrium. We identify a network of aromatic interactions and hydrogen bonds that regulates hMGL active-inactive state interconversion. The data highlight specific inter-residue interactions within hMGL modulating the enzymes function and implicate transitions between active (open) and inactive (closed) states of the hMGL lid domain in controlling substrate access to the enzymes active site. 相似文献
67.
68.
Recent evidence suggests that alterations in oxidative metabolism induced by thiamine deficiency lead to neuronal cell death. However, the molecular mechanisms underlying this process are still under extensive investigation. Here, we report that rat pheochromocytoma PC-12 cells differentiated in the presence of NGF into neurons undergo apoptosis due to thiamine deficiency caused by antagonists of thiamine - amprolium, pyrithiamine and oxythiamine. Confocal laser scanning fluorescence microscopy revealed that annexin V binds to PC-12 cells in presence of thiamine antagonists after 72 h incubation. Results also show that thiamine antagonists trigger upregulation of gene expression of mitochondrial-derived apoptosis inducing factor, DNA fragmentation, cleavage of caspase 3 and translocation of active product to the nucleus. We therefore propose that apoptosis induced by amprolium, pyrithiamine or oxythiamine occurs via the mitochondria-dependent caspase 3-mediated signaling pathway. In addition, our data indicate that pyrithiamine and oxythiamine are more potent inducers of apoptosis than amprolium. 相似文献
69.
New data on the species composition and comparative analysis of gamasid mites occurring on small mammals in the semi-desert territories of Saratov Trans-Volga region are reported. In all, 18 species of gamasid mites (9 genera, 5 families) were found, including 9 species which had not been previously recorded in the region: Hypoaspis (Stratiolaelaps) miles Berlese, 1882, H. (Geolaelaps) heselhausi Oudemans, 1912, H. (G.) lubrica Oudemans et Voigts, 1904, Laelaps multispinosus Banks, 1909, L. jettmari Vitzthum, 1930, Cyrtolaelaps mucronatus G. et. R. Canestrini, 1881, Haemogamasus citelli Bregetova et Nelzina, 1952, Hirstionyssus eusoricis Bregetova, 1956, and Hi. ellobii Bregetova, 1956; 5 of these species are new to Saratov Province. 相似文献
70.
Differentiation of neuronal stem cells into astrocytes or neurons is important in maintaining brain function. Oxidative stress and inflammation are now shown to bias differentiation toward astrocytes by modulating activity of the anti-ageing gene Sirt1. These findings link a longevity gene to the activity of neuronal stem cells and their response to stress. 相似文献