It has long been known that the phytohormone auxin plays a promoting role in tuber formation and stress tolerance in potatoes. Our study aimed to identify and characterize the complete sets of ...auxin-related genes that presumably constitute the entire auxin signaling system in potato (
L.). The corresponding genes were retrieved from sequenced genomes of the doubled monoploid
DM1-3-516-R44 (DM) of the Phureja group, the heterozygous diploid line RH89-039-16 (RH), and the autotetraploid cultivar Otava. Both canonical and noncanonical auxin signaling pathways were considered. Phylogenetic and domain analyses of deduced proteins were supplemented by expression profiling and 3D molecular modeling. The canonical and ABP1-mediated pathways of auxin signaling appeared to be well conserved. The total number of potato genes/proteins presumably involved in canonical auxin signaling is 46 and 108 in monoploid DM and tetraploid Otava, respectively. Among the studied potatoes, spectra of expressed genes obviously associated with auxin signaling were partly cultivar-specific and quite different from analogous spectrum in Arabidopsis. Most of the noncanonical pathways found in Arabidopsis appeared to have low probability in potato. This was equally true for all cultivars used irrespective of their ploidy. Thus, some important features of the (noncanonical) auxin signaling pathways may be variable and species-specific.
Heteroatom doping is a widely used method for the modification of the electronic and chemical properties of graphene. A low-pressure chemical vapor deposition technique (CVD) is used here to grow ...pure, nitrogen-doped and phosphorous-doped few-layer graphene films from methane, acetonitrile and methane-phosphine mixture, respectively. The electronic structure of the films transferred onto SiO
/Si wafers by wet etching of copper substrates is studied by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy using a synchrotron radiation source. Annealing in an ultra-high vacuum at ca. 773 K allows for the removal of impurities formed on the surface of films during the synthesis and transfer procedure and changes the chemical state of nitrogen in nitrogen-doped graphene. Core level XPS spectra detect a low
-type doping of graphene film when nitrogen or phosphorous atoms are incorporated in the lattice. The electrical sheet resistance increases in the order: graphene < P-graphene < N-graphene. This tendency is related to the density of defects evaluated from the ratio of intensities of Raman peaks, valence band XPS and NEXAFS spectroscopy data.
We propose a method for constructing asymptotic representations of solutions of linear degenerate second-order ordinary differential equations, which permits one to construct exact asymptotics of ...solutions in a neighborhood of the degeneracy point. An example where one finds a power-law asymptotics is given.
New results of experimental study of the process of rise of a spherically shaped group of monodisperse bubbles in the presence of a surfactant in the region of Reynolds numbers Re = 200–600 have been ...presented. The influence of the nature of a surfactant on the dynamics of rise of the group of bubbles has been analyzed. Experimental data have been obtained on the trajectory of rise of bubbles forming the group depending on the type of surfactant in the liquid. The authors were the first to obtain experimental data on the velocity and the coefficient of resistance of a group of monodisperse bubbles rising in the presence of different surfactants. Criterial dependences have been obtained for dimensionless velocity of rise of a group of monodisperse bubbles as a function of the type of surfactant in the liquid.
The non-competitive NMDA glutamate receptor antagonist memantine has neuroprotective properties and is the first non-cholinergic drug approved for the treatment of Alzheimer’s disease. The purpose of ...this work was to test the hypothesis that injections of memantine to healthy animals can affect the subunit composition of NMDA receptors in the brain, which may explain the effects of its chronic administration. For this, the expression of subunits GluN1, GluN2A, GluN2B, and GluN2C was studied in the hippocampus and prefrontal cortex of rats after single or five subchronic injections of memantine. The results showed that the GluN2C subunit (
GRIN2C
) plays an important role in the effects of memantine; against the background of memantine treatment, the expression of this subunit markedly decreased in the prefrontal cortex, but not in the hippocampus, which significantly affected the excitation/inhibition balance in cortical structures.
Cytokinins (CKs) control many plant developmental processes and responses to environmental cues. Although the CK signaling is well understood, we are only beginning to decipher its evolution. Here, ...we investigated the CK perception apparatus in early-divergent plant species such as bryophyte
, lycophyte
, and gymnosperm
. Of the eight CHASE-domain containing histidine kinases (CHKs) examined, two CHKs, PpCHK3 and PpCHK4, did not bind CKs. All other CHK receptors showed high-affinity CK binding (
of nM range), with a strong preference for isopentenyladenine over other CK nucleobases in the moss and for
-zeatin over
-zeatin in the gymnosperm. The pH dependences of CK binding for these six CHKs showed a wide range, which may indicate different subcellular localization of these receptors at either the plasma- or endoplasmic reticulum membrane. Thus, the properties of the whole CK perception apparatuses in early-divergent lineages were demonstrated. Data show that during land plant evolution there was a diversification of the ligand specificity of various CHKs, in particular, the rise in preference for
-zeatin over
-zeatin, which indicates a steadily increasing specialization of receptors to various CKs. Finally, this distinct preference of individual receptors to different CK versions culminated in vascular plants, especially angiosperms.
Powders of various metals and boron are widely used in composite solid propellants to increase the combustion temperature and specific impulse of rocket engines. This paper presents the results of an ...experimental study of oxidation and ignition of ultrafine Alex aluminum powder, amorphous boron, microsized
Al aluminum powder, and AlB
2
and AlB
12
aluminum borides in air. Metal and boron powders are heated and ignited by a CO
2
laser in a heat flux density range of 65–190 W/cm
2
. It is revealed on the basis of thermal analysis data that the powder reactivity parameters are arranged in the following sequence (in descending order of activity): Alex
B
AlB
12
AlB
2
Al. The total specific heat release and the mass variation rate reach maximum values during the oxidation of amorphous boron and AlB
12
aluminum dodecaboride. The Alex, boron, and AlB
12
powders are easier to ignite in air under the action of an external radiant source. The power exponent
in a dependence between the ignition delay time
and the heat flux density
=
for the
Al, AlB
2
, and AlB
12
powders are approximately the same and equal to
2.0, and it is lower and reaches
= 1.5 and 1.0 for ultrafine Alex and boron powders, respectively.
The signaling of cytokinins (CKs), classical plant hormones, is based on the interaction of proteins that constitute the multistep phosphorelay system (MSP): catalytic receptors-sensor histidine ...kinases (HKs), phosphotransmitters (HPts), and transcription factors-response regulators (RRs). Any CK receptor was shown to interact in vivo with any of the studied HPts and
. In addition, both of these proteins tend to form a homodimer or a heterodimeric complex with protein-paralog. Our study was aimed at explaining by molecular modeling the observed features of
protein-protein interactions, accompanying CK signaling. For this purpose, models of CK-signaling proteins' structure from Arabidopsis and potato were built. The modeled interaction interfaces were formed by rather conserved areas of protein surfaces, complementary in hydrophobicity and electrostatic potential. Hot spots amino acids, determining specificity and strength of the interaction, were identified. Virtual phosphorylation of conserved Asp or His residues affected this complementation, increasing (Asp-P in HK) or decreasing (His-P in HPt) the affinity of interacting proteins. The HK-HPt and HPt-HPt interfaces overlapped, sharing some of the hot spots. MSP proteins from Arabidopsis and potato exhibited similar properties. The structural features of the modeled protein complexes were consistent with the experimental data.
This paper presents the results of an experimental study of the processes of thermal decomposition and ignition of high-energy materials (HEMs) containing an oxidizer, a combustible binder, and ...dispersed additives of aluminum, aluminum borides (AlB
2
and AlB
12
), and amorphous boron. A Netzsch STA 449 F3 Jupiter thermal analyzer and an experimental testbed, which includes a continuous-wave CO
2
laser, are used to investigate the response and ignition characteristics of two basic HEM compositions based on AP/SKDM/Me and AP/AN/MPVT/Me at different heating rates. It is revealed that ammonium nitrate at low heat flux densities (
W/cm
2
) decomposes and melts, forming a liquid layer on the reaction surface and increasing the delay time of the emergence of a HEM flame containing Al, AlB
2
, and AlB
12
. As the heat flux density becomes higher, the effect of the liquid layer on the reaction surface of the sample decreases due to an increase in the surface temperature, the outflow rate of gaseous decomposition products, and the layer evaporation.
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