The influenza NS1 protein is involved in suppression of the host immune response. Recently, there is growing evidence that prion-like protein aggregation plays an important role in cellular signaling ...and immune responses. In this work, we obtained a recombinant, influenza A NS1 protein and showed that it is able to form amyloid-like fibrils in vitro. Using proteolysis and subsequent mass spectrometry, we showed that regions resistant to protease hydrolysis highly differ between the native NS1 form (NS1-N) and fibrillar form (NS1-F); this indicates that significant structural changes occur during fibril formation. We also found a protein fragment that is capable of inducing the process of fibrillogenesis at 37 °C. The discovery of the ability of NS1 to form amyloid-like fibrils may be relevant to uncovering relationships between influenza A infection and modulation of the immune response.
•Recombinant NS1 protein is capable of forming amyloid-like fibrils.•Native form NS1 features a protease-resistant fragment from a.a. residues 1 to 78.•The fibrillar NS1 form's C-terminus is hydrolyzed by trypsin least of all.•During fibril formation, SDS-resistant non-native dimers form.•The NS1 Beta domain likely plays an important role in conformational transition.
Dormancy is the final stage of tuber life serving to preserve tubers as organs of vegetative reproduction under unfavorable growth conditions. Since the duration of potato tuber dormancy and their ...sprouting time have significant economic importance, much attention is given to the study of the regulation of these processes. This review considers metabolite, genetic, and hormonal aspects of regulation of potato (Solanum tuberosum L.) tuber dormancy and sprouting. Particular attention is paid to the relationship between processes occurring in different parts of the tuber: its storage tissues and buds. The interaction of hormonal and metabolite (carbohydrate) regulation of dormancy and sprouting is discussed.
The biological activity in oligotrophic peatlands at the margins of the Vasyugan Mire has been studied. It is shown found that differently directed biochemical processes manifest themselves in the ...entire peat profile down to the underlying mineral substrate. Their activity is highly variable. It is argued that the notion about active and inert layers in peat soils is only applicable for the description of their water regime. The degree of the biochemical activity is specified by the physical soil properties. As a result of the biochemical processes, a micromosaic aerobic–anaerobic medium is developed under the surface waterlogged layer of peat deposits. This layer contains the gas phase, including oxygen. It is concluded that the organic and mineral parts of peat bogs represent a single functional system of a genetic peat profile with a clear record of the history of its development.
This paper presents the results of a study of the dielectric response in single crystals of barium strontium niobate doped with thulium of various concentrations. It is shown that the dielectric ...permittivity increases with increasing concentration of thulium. For as-grown samples the dispersion of the permittivity is observed in the frequency region of 10
6
Hz. The dependence is not observed for the samples polarized under DC field. For all the samples studied, the switched polarization increases and the coercive field decreases under action of an AC field.
—To describe the processes of fuming copper smelting slags by the products of methane conversion by oxygen at oxygen consumption coefficients (α) varying from 0.25 to 0.75 in the temperature range ...1473–1773 K, we have developed a thermodynamic modeling technique for open systems with fractional introduction of an initial reducing gas and periodic removal of a metallic phase and waste gases from a working medium. Relations between the contents of iron and zinc oxides in an oxide melt and the degrees of their reduction and the temperature and the amount of the introduced reducing agent are revealed. The thermodynamic equilibrium of a system is calculated on the assumption that solutions are ideal; that is, the activity coefficient of zinc oxide is 1. Under the real conditions of the slag melt of copper smelting,
a
ZnO
is close to 3. Therefore, the quantitative indicators of industrial smelting differ from the calculated ones. However, the change in the smelting parameters relative to each other would be the same. The main result of this work is a comparative analysis of the processes depending on the reducing gas temperature and composition. The amount of conversion products and, accordingly, natural gas required for their production, which is necessary for metal reduction to a given degree of zinc recovery, significantly depends on the gas temperature and composition. The data obtained are useful for predicting the thermal extraction processes that occur during the extraction of useful components from nonferrous metallurgy slags.
—The fuming of copper smelting slag in a Vanyukov furnace by the products of methane conversion by oxygen, water vapor, and carbon dioxide in the temperature range 1473–1773 K is thermodynamically ...modeled. For this purpose, a technique is developed to describe the changes in the phase compositions in the systems under study during their bubbling as functions of the amount of an introduced reducing gas; this technique is characterized by cyclic calculations and the removal of the formed gases and metal phase from the working medium composition. The calculation results demonstrate that the interaction of the gas with melt oxides proceeds in two stages regardless of the melt composition. At the first stage, Fe
3
O
4
is reduced to FeO and ZnO, to Zn. Therefore, the content of Fe
3
O
4
and ZnO in the melt decreases and that of FeO increases. At the second stage, metallic iron appears and the content of iron and zinc oxides decreases. A significant influence of temperature on fuming is shown. When the temperature increases from 1473 to 1773 K, the fuming process is significantly intensified, which is accompanied by a fourfold decrease in the amount of the reducing gas required to achieve close degrees of zinc recovery. The gas composition weakly affects the process. The most effective reducing agent is shown to be the gas formed by the steam conversion of methane, which is due to the minimal costs of its production. The results obtained make it possible to predict the indicators of the process of fuming by methane conversion products and will be useful for creating new technologies.
Swamps and wetlands in forested areas, as well as nonforest swamps, are collectively involved in the global carbon cycle. They play an important role in depositing greenhouse gases. This article ...analyzes the long-term dynamics of concentration of greenhouse gases (CO
2
and CH
4
) in a peat deposit and their emission in a natural and reclaimed oligotrophic bog in the southern taiga zone of Western Siberia. It is shown that a significant role in the dynamics of CO
2
and CH
4
concentration in peat deposits is played by weather conditions in each month of the warm period, as well as by the botanical composition, the activity of biochemical processes, and the structure and physical and mechanical properties of peat deposits. We have also identified the intradeposit spatial and temporal dynamics of indices of greenhouse gas concentrations. It has been proven that there are multicomponent dependences of CO
2
and CH
4
concentrations on parameters of external and intradeposit conditions. Parameters of concentrations in the peat deposit of the oligotrophic bog from the swampy catchment basin of the Klyuch River have been determined as follows: extreme concentrations of CO
2
were 0.002–3.64 mmol/dm
3
and extreme concentrations of CH
4
were 0.003–2.03 mmol/dm
3
; normalized CO
2
fluxes varied from /–22.2/ to 157.8 mg C/(m
2
h), the extreme values of normalized CH
4
fluxes were /–3.0/–5.3 mg C/(m
2
h), CO
2
fluxes for the warm period were 20–110 g C/(m
2
year), and CH
4
fluxes for the warm period were 0.8–3.7 C/(m
2
year). A slight increase in the activity of normalized CO
2
fluxes has been recorded at the forest reclamation site compared to a natural swamp, while the concentrations of greenhouse gases in the peat deposit have proven to be comparable in both cases. It is shown that the absence of an operating drainage system leads to rebogging. The vast areas of swamps on the West Siberian Plain and the aggressive pattern of bogging implies moderate and selective forest reclamation for its taiga zone.
Tuber formation is a complex process comprising several stages: stolon formation and growth, induction of tuberization, tuber initiation, and tuber growth. This review considers successive stages of ...tuber formation and their hormonal regulation. Special attention is paid to the effects on tuber formation of such phytohormones as gibberellins, cytokinins, jasmonic acid, and auxins. Physiological and some molecular-genetic aspects of their action on tuber photoperiodic induction and initiation are discussed.
The density and surface tension of homogeneous molten slags from the joint smelting of nickel saprolite and copper pyrite ores have been experimentally assessed (maximum bubble pressure method) using ...model samples of iron-containing slage (8.9 wt.% CaO + 11.8 wt.% MgO + 12.5 wt.% Al
2
O
3
+ 47.4 wt.% SiO
2
+ 13.3 wt.% FeO + 5.0 wt.% Fe
2
O
3
) and iron-free slag (12.5 wt.% CaO + 16.0 wt.% MgO + 9.4 wt.% Al
2
O
3
+ 58.3 wt.% SiO
2
), which represent the composition and structure of real prototypes in the temperature ranges of 1550–1300°C and 1550–1400°C, respectively. A decrease in temperature leads to an increase in the density and surface tension of these slags in the ranges of 1.85–2.21 and 2.23–2.29 g·cm
–3
and 144–250 and 340–345 mN·m
–1
, respectively. The structural changes after the change over from the former composition to the latter one are due to the decrease in basicity from 0.7 to 0.6 and the replacement of Fe
2+
by Ca
2+
and Mg
2+
. The latter factor makes the major contribution to the increase of the characteristics themselves and their temperature coefficients (from –0.0015 to –0.0004 g·cm
–3
·°C
–1
and from –0.4 to –0.1 mN·m
–1
·°C
–1
, respectively). The regression analysis of the experimental data was performed to obtain empirical models that accurately predict the density and surface tension of real slags from the smelting of copper and nickel raw materials in the temperature range considered. The results obtained can be used in developing and improving metallurgical technologies and in the glass and ceramic industries.
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