The interaction between the secondary structure elements is the key process, determining the spatial structure and activity of a membrane protein. Transmembrane (TM) helix-helix interaction is known ...to be especially important for the function of so-called type I or bitopic membrane proteins. In the present work, we present the approach to study the helix-helix interaction in the TM domains of membrane proteins in various lipid environment using solution NMR spectroscopy and phospholipid bicelles. The technique is based on the ability of bicelles to form particles with the size, depending on the lipid/detergent ratio. To implement the approach, we report the experimental parameters of “ideal bicelle” models for four kinds of zwitterionic phospholipids, which can be also used in other structural studies. We show that size of bicelles and type of the rim-forming detergent do not affect substantially the spatial structure and stability of the model TM dimer. On the other hand, the effect of bilayer thickness on the free energy of the dimer is dramatic, while the structure of the protein is unchanged in various lipids with fatty chains having a length from 12 to 18 carbon atoms. The obtained data is analyzed using the computer simulations to find the physical origin of the observed effects.
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•Approach to measure the free energy of dimerization in bicelles was developed.•Membrane contents affect the stability of transmembrane dimer.•Membrane thickness does not influence the structure of a dimer.•Membrane contents effects are not explained by any single factor of the environment.
Abstract
Hematological and histopathological study results of adult carp from a private fish farm are presented. Abnormalities in the main hematological parameters (blood elements ratio, leukocyte ...formula, erythropoiesis level, possible pathologies of erythrocytes) were not revealed. One third of the examined fish were found to have abnormalities in the tissues of gills, liver, and heart muscle in the form of minor focal formations (detachment of the gill epithelium, dissection of myofibrils, disorders of glycogen metabolism, foci of necrosis and infiltration) which indicates the initial stage of the pathological process. Kidneys, gonads, and somatic muscle fibers showed no signs of pathology. The main factors determining the primary signs of internal organ diseases are water quality (water saturated with magnesium, calcium, and iron salts, increased hardness) and an unbalanced diet (primarily, an insufficient amount of raw protein) that does not meet the standards adopted in fish farming. The registered initial signs of the pathological process in the gills, liver and heart muscle can be leveled by improving the carp keeping conditions.
Abstract
The article proposes a technical solution for a multi-frequency meter of electrical impedance parameters based on a precision impedance converter AD5933 from analog devices. The technical ...solution can be used in the development of portable devices for the diagnosis of biological objects.
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A radiometric complex for astronomical and atmospheric research in the 3-mm wavelength range has been developed. The radiometer is assembled according to the modulation scheme with a mechanical ...obturator based on oversized quasi-optical waveguides. A Cassegrain antenna with 1° far-field pattern at a −3 dB level is used as the antenna system. Calibration is carried out using a built-in noise generator. The receiving system of the radiometer, together with the antenna, is placed on a two-coordinate turntable for observations in a selected region of the celestial sphere. Control, as well as capture and processing of experimental data, are performed remotely using the developed software.
In the case of soluble proteins, chemical shift mapping is used to identify the intermolecular interfaces when the NOE-based calculations of spatial structure of the molecular assembly are impossible ...or impracticable. However, the reliability of the membrane protein interface mapping based on chemical shifts or other relevant parameters was never assessed. In the present work, we investigate the predictive power of various NMR parameters that can be used for mapping of helix–helix interfaces in dimeric TM domains. These parameters are studied on a dataset containing three structures of helical dimers obtained for two different proteins in various membrane mimetics. We conclude that the amide chemical shifts have very little predictive value, while the methyl chemical shifts could be used to predict interfaces, though with great care. We suggest an approach based on conversion of the carbon NMR relaxation parameters of methyl groups into parameters of motion, and one of such values, the characteristic time of methyl rotation, appears to be a reliable sensor of interhelix contacts in transmembrane domains. The carbon NMR relaxation parameters of methyl groups can be measured accurately and with high sensitivity and resolution, making the proposed parameter a useful tool for investigation of protein-protein interfaces even in large membrane proteins. An approach to build the models of transmembrane dimers based on perturbations of methyl parameters and TMDOCK software is suggested.
The effect of ultra-fast (induction) heating of a commercial Fe–3% Si alloy strip (grain oriented electrical steel) at a rate of ~100°С/s on the magnetic properties of finished product is studied in ...this work. This heating is accomplished after cold rolling followed by recrystallizing decarburizing annealing. It is shown that, in parallel with a reference sample, the ultra-fast heating leads (1) after recrystallizing decarburizing annealing to an increase in the average ferrite grain and, within the near-surface layer, to an increase in the edge component of the {110}〈001〉 texture and decrease in the fraction of {111}〈112〉 component; (2) after the second cold rolling at the final stages of annealing before secondary recrystallization, to an increase in the sharpness of the {110}〈001〉 component; and (3) in the finished product, to a decrease in the average macrograin size by 1.5 times (from ~9 to ~6 mm) and a decrease in the average angle of deviation of easy magnetization axes 〈001〉 from the rolling direction from ~7° to ~6°. The magnetic properties of the studied material exceed those of the comparison metal in all cases. The effect of ultra-fast heating on the texture transformations in the alloy and the formation of the final properties are explained by different nucleation places of grains of different orientations upon primary recrystallization.
The parasite fauna of the monkey goby
Neogobius fluviatilis
has been studied from the lower part of the Saratov Reservoir. Six species of parasites are recorded, for one of which (the goby-specific ...plerocercoid
Triaenophorus crassus
) the monkey goby is recorded as an additional host for the first time. The 100% invasion of the goby by the alien fluke
Nicolla skrjabini
makes it possible to attribute it to the main definitive hosts of the parasite in the water body.
Baby-MIND neutrino detector Mefodiev, A. V.; Kudenko, Yu. G.; Mineev, O. V. ...
Physics of particles and nuclei,
11/2017, Letnik:
48, Številka:
6
Journal Article
Recenzirano
Odprti dostop
The main objective of the Baby-MIND detector (Magnetized Iron Neutrino Detector) is the study of muon charge identification efficiency for muon momenta from 0.3 to 5 GeV/
c
. This paper presents the ...results of measurement of the Baby-MIND parameters.
Tokamak research at the Ioffe Institute Bakharev, N.N.; Abdullina, G.I.; Afanasyev, V.I. ...
Nuclear fusion,
11/2019, Letnik:
59, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Recent research at three small tokamaks with different parameters located at the Ioffe Institute-the spherical tokamak Globus-M, the large aspect ratio tokamak FT-2 and the compact tokamak ...TUMAN-3M-are reviewed. This overview covers energy confinement (Globus-M and FT-2), L-H transition (TUMAN-3M and FT-2), Alfvén waves (Globus-M and TUMAN-3M), ion cyclotron emission (TUMAN-3M), major plasma discharge disruption (Globus-M) and scrape-off layer (Globus-M) studies. A full-f global gyrokinetic modeling benchmark using synthetic diagnostics in FT-2 is described. Anomalous absorption and emission in electron cyclotron resonance heating experiments due to the parametric excitation of localized upper hybrid waves are analyzed theoretically. Progress in the development of the neutral particle analysis, gamma-ray spectrometry and divertor Thomson scattering combined with laser-induced fluorescence diagnostics for ITER is discussed. The status of the new Globus-M2 spherical tokamak is reported.
The infestation of fish in the Saratov Reservoir with the cestode Triaenophorus crassus (Cestoda, Pseudophyllidea) was studied. The material was collected in 2009–2015 from the middle part of the ...reservoir; complete parasitological dissection of Neogobius melanostomus (Pallas) – 320 ind., Neogobius iljini (Vasiljeva et Vasiljev) – 146 ind., Proterorhinus marmoratus (Pallas) – 21 ind., and Esox lucius (Linnaeus) – 49 ind. was carried out. The plerocercoids of T. crassus were mainly found in the muscles of gobies, also alien to the Saratov Reservoir. The highest invasion rates (50%, 2.15 ind.) were registered in N. iljini, a second intermediate host of the cestode in the Saratov Reservoir. The parasite reaches maturity in pike, a definitive host. The high level of pike infection with the cestode (55.1%, 6.4 ind.) can be due the key role of gobies in pike feeding. The obtained results confirm the ongoing transformation of the system of food chains and the successful adaptation of T. crassus in the reservoir.
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