Poly(ADP-ribose) polymerase 1 (PARP1) is a key enzyme that regulates important cellular processes, including DNA repair. PARP1 binds to a DNA damage site and synthesizes poly(ADP-ribose) chains ...(PARs), which serve as a signal of DNA damage for other DNA repair enzymes. PARP1 is a recognized target for the development of anti-cancer drugs. In this work, a method is developed that makes it possible to investigate the complex formation of PARP1 with DNA as well as its dissociation by detecting the fluorescence anisotropy of this complex during the poly(ADP-ribose) synthesis. The method allows investigation of the inhibition of PARP1 activity in the presence of its inhibitors. In this work, we demonstrated that PARP1 is activated by DNA duplexes containing a damage and a fluorophore at the 3′-end of one of the DNA duplex chains. The effects of the clinical inhibitor olaparib on the activity of PARP1 was studied. It was shown that olaparib has no influence on the binding of PARP1 to the model DNA structures used, but it significantly inhibits the poly(ADP-ribosyl)ation of PARP1. The proposed convenient method for the real-time determination of the PARP1 activity can be used to screen PARP1 inhibitors with the calculation of quantitative inhibition parameters.
The capacity of human poly(ADP-ribose) polymerase-1 (PARP-1) to interact with intact apurinic/apyrimidinic (AP) sites in DNA has been demonstrated. In cell extracts, sodium borohydride reduction of ...the PARP-1/AP site DNA complex resulted in covalent cross-linking of PARP-1 to DNA; the identity of cross-linked PARP-1 was confirmed by mass spectrometry. Using purified human PARP-1, the specificity of PARP-1 binding to AP site-containing DNA was confirmed in competition binding experiments. PARP-1 was only weakly activated to conduct poly(ADP-ribose) synthesis upon binding to AP site-containing DNA, but was strongly activated for poly(ADP-ribose) synthesis upon strand incision by AP endonuclease 1 (APE1). By virtue of its binding to AP sites, PARP-1 could be poised for its role in base excision repair, pending DNA strand incision by APE1 or the 5'-dRP/AP lyase activity in PARP-1.
We studied the influence of river discharge and timing of ice retreat on sinking fluxes of total particulate matter and its components in the Laptev Sea in August–September 2017 and 2018. Vertical ...fluxes were measured with short‐term sediment traps located on the shelf adjusted to the Lena and Khatanga Rivers inflows (four shallow stations in 2017) and in Vilkitski Strait/Trough area (two deeper stations) in 2018. One station outside the Khatanga plume was repeated in both years. The effect of river discharge manifested by high total particle flux (1–1.6 g m−2 d−1), high Si (0.3 g m−2 d−1) and Al (0.1 g m−2 d−1) fluxes, a high proportion of terrigenous organic carbon (10.7%–27.5% total organic carbon) was clearly recognizable only in the shelf area closest to the Lena inflow. Large contribution of the lithogenic matter to the flux on the Laptev shelf is suggested to result also from sediment resuspension (caused by the tidal mixing and upwelling events), lateral offshore transport of sediment just above the seabed, and coastal abrasion. The magnitude of vertical fluxes of total particulate matter and organic carbon was two to three times higher in 2017 (late ice retreat) than in 2018 (early ice retreat). Centric diatoms dominated protist flux in 2017 while in 2018, dinoflagellates and tintinnids dominated. The contribution of protists to the biogenic organic carbon flux reached 62% in 2018 versus <1% in 2017. Zooplankton fecal pellet flux was not influenced by river discharge but was higher soon after ice melt.
Plain Language Summary
A major process in the ocean carbon cycle assumingly vulnerable to climate changes in the export of carbon from the surface to the deep ocean via the sinking of particulate matter. As recent warming is especially important for the Arctic Ocean, studies on the vertical fluxes there attract increasing attention. The poorly studied Laptev Sea, which is located in the center of the Siberian shelf, is of particular interest due to the high freshwater inflow and ice production. We studied the magnitude and composition of the vertical fluxes affected by riverine discharge and the timing of ice retreat. The effect of the river discharge was manifested by the increase of the total particle flux dominated by the lithogenic component and a higher share of lithogenic carbon in the organic carbon flux than outside the freshwater plume. Elevated lithogenic flux on the Laptev shelf is related not only to the riverine discharge, but also to the sediment resuspension, lateral offshore transport of sediment just above the seabed, and coastal abrasion. The timing of ice cover melt appears crucial in determining the patterns of vertical export with the higher fluxes observed soon after the sea ice brake up.
Key Points
New insights on the impact of riverine discharge and time of ice retreat on vertical particle fluxes in the Laptev Sea is presented
The effect of the river discharge was manifested by the increase of the total particle flux dominated by the lithogenic component
The timing of ice retreat is crucial in determining the patterns of vertical export with higher fluxes observed soon after ice break up
The basic scheme of the work of an intelligent control system for the dynamic processes of seed preparation for sowing, which allows accelerating the transition to progressive technologies of crops ...cultivation, is considered. The intelligent control system built into the biotech system works proactively in real-time and is designed to make the operator's work easier and faster. The intelligent control system allows timely and effortless control of the preparation and the treated seeds. The use of an intelligent control system reduces the mental and physical stress on the operator during work by 50% or more, without reducing the quality of seed processing; improves the quality of decisions made; reduces the duration of control by more than two times in comparison with the existing methods of control and management of the process of pre-sowing seed treatment.
The research was done on the basis of monthly samples collected by sediment trap exposed over the outer shelf of the Kara Sea from September 2018 to July 2019. Vertical fluxes of phytoplankton and ...its dominating components, as well as tintinnids and stinging cells of coenenterates, were evaluated. The maximum phytoplankton sedimentation, in which large-size centric diatoms dominated, was observed in May and associated with the formation of spacious polynya in seasonal ice cover. The maximum number of phytoplankton reached 6.5 × 10
6
cells/m
2
/day, the wet biomass was 17.7 mg/m
2
/day, and the carbon biomass was 1.17 mgС/m
2
/day. The vertical flux of particulate organic matter (POM) was low (4.1 mgС/m
2
/day), and the phytoplankton contribution to POM reached its maximum of 28.5% for the whole observation period. High numbers and biomass of phytoplankton with domination of species typical for ice blooms were registered in the June sample in the period of seasonal ice melting. The minimal values of algae abundance in sediment samples were observed from January to April. With the exception of May, the share of phytoplankton in POM did not exceed 3%. The numbers of tintinnids were highest in September–November, and those of stinging cells of coenenterates from September to December and in May. In autumn months, the contribution of tintinnids to POM was comparable with that of phytoplankton.
The material was obtained on July 18–24, 2016 in the area comprising the Ob River estuary and the adjacent shelf of the Kara Sea (71°28.3′–74°38.8′ N).
Euglena
sp. bloom (class Euglenophyceae, order ...Euglenales), unique for estuarine regions of large Siberian rivers and the Arctic shelf, is described and quantitatively characterized. Bloom was clearly confined to the outer wide part of the Ob River estuary. In the areas of maximum abundance of
Euglena
sp
.
, its average population density reached 2.9 × 10
6
cells/L in the water column; this species accounted for more than 80% of the total phytoplankton abundance; the share of spores in total abundance did not exceed 2.5%. The shallow shelf adjacent to the Ob River estuary was the area of
Euglena
sp
.
removal, as evidenced by a more than fourfold decrease in the abundance of this species and the predominance of spores in the population (75–98%).
Euglena
sp
.
bloom was associated exclusively with the outer part of the Ob River estuary. The dominance of this species in the phytoplankton community of this area made it possible to report for the first time on the presence of a specific quantitatively rich phytocoenose, developing under certain conditions and confined to the estuary of a large Arctic river.
We analyzed the taxonomic structure and spatial variability of phytoplankton abundance and biomass in the Chukchi and Beaufort Seas during spring and summer seasons of the SBI program. Phytoplankton ...samples were collected during two surveys from May 10 to June 13 and from July 19 to August 21 of 2002. In May and June, ice cover exceeded 80% over most of the study area and there was no vertical stratification, indicating that the successional state of the phytoplankton corresponded to the end of the winter biological season. The phytoplankton abundance ranged from a few tens to a few thousands of cells per liter, while biomass varied from 0.1 to 3.0
mg
C
m
−3. Small areas of high phytoplankton abundance (0.13–1.3×10
6
cells
L
−1) and biomass (22–536
mg
C
m
−3), dominated by early spring diatoms
Pauliella taeniata and
Fragilariopsis oceanica in the surface waters, which indicated the beginning of the spring bloom, were observed only in the southeastern part of the Chukchi shelf and off Point Barrow. In July and August summer period, more than a half of the study area had <50% ice cover and the water column was stratified by temperature and salinity. Over the Chukchi shelf and continental slope of the Beaufort Sea, the phytoplankton abundance and biomass were an order of magnitude higher in July–August than in May–June. The taxonomic diversity of algae also increased due to the appearance of late-spring and summer diatoms, dinoflagellates, and coccolithophorids (
Emiliania huxleyi). Interestingly, the seasonal differences between phytoplankton abundance and taxonomic composition in the spring and summer periods varied the least over the Chukchi Sea slope and in the deep-water area of the Arctic Ocean. High algae concentrations in summer were located in the lower layers of the euphotic zone, suggesting that the spring bloom on both the Chukchi shelf and in the western part of the Beaufort Sea occurred in late June/early July. In the spring and summer, the microalgal community was characterized by a high abundance of 4–10
μm flagellates, which exceeded the abundance of all other taxonomic groups. In both seasons studied, phytoplankton reached its maximum abundance within restricted areas in the southern part of the Chukchi Sea southwest of Point Hope, in the northern part of the Chukchi shelf between the 50- and 100-m isobaths, on the shelf northwest of Point Barrow, and over the continental slope in the Beaufort Sea. The pronounced spatial difference in the seasonal state was a characteristic feature of the phytoplankton community in the western Arctic.
A neutron collimator is developed to attenuate the neutron flux and reduce the residual induced activity in the interportal space of the diagnostic system of neutral particle analyzers of the ITER ...tokamak reactor. The collimator is installed in the port plug of the ITER vacuum vessel in front of an inlet to the vacuum pipeline of the diagnostic system. The collimator design has a cellular structure with 80% transparency for the neutral atom beam that goes out of the plasma and is recorded by the analyzers. However, because of increased scattering of neutrons in the collimator, their flux in the interportal room in the service zone of diagnostic systems of equatorial port no. 11 is significantly reduced and allows the equivalent dose rate in this zone to be decreased by several times. Thermal analysis showed that, during the reactor operation in modes with generation of the maximum power of 500 MW, the plasma radiation will cause the heating of the collimating grid to a temperature not exceeding 250°C, which makes it possible to select the stainless steel (316L(N)-ITER grade) as a material for manufacturing the collimator. In this case the cyclic strength of the collimator meets the ITER requirements, and it can be used without replacement during the entire deuterium-tritium experiment of the tokamak reactor.
In the conditions of agriculture biologization an urgent problem is to exclude the destruction of seeds and reduce their injury by the working bodies of machines. The advantages of using equipment ...with highly elastic working bodies in shock-absorbing technologies for preparing seeds for sowing are described. The process of interaction of seeds with reflective work surfaces was studied experimentally on a specially developed laboratory installation. Elastic working bodies of such devices provide a "gentle shock wave" mode, the impact of which on easily injured legume and potato seeds contributes to the development of positive dynamics of physiological processes in the seed, without injury and destruction of seeds. The impulse pressure is created by the shaking action of the elastic shell on the seeds. By adjusting the amplitude and frequency of vibrations of the elastic shell, it is possible to achieve the necessary value of the impact on the seeds, creating an impulse pressure on the seeds within the limits of those norms. The last, on the one hand, do not have a destructive effect on the seeds. On the other hand, contribute to increasing seed productivity. The developed shock-absorbing technology makes it possible to combine the use of both chemical and biological means of seed protection in large agricultural holdings, as well as in medium and small agricultural enterprises.
The deep structure of the Earth’s crust and the surface of the mantle lithosphere of the East European platform are considered. In the three main layers (lower, middle, and upper) of the Earth’s ...crust, as well as in the surface of the mantle lithosphere, deformations expressed in the changing thickness of the layers have been identified for the first time. Deformations in all layers were compared to distinguish active centers and principal (cross-cutting) and local (manifested in separate layers) regions. The boundaries of these regions are active zones of different ranks. The observed occurrence of cross-cutting deformations from layer to layer or in separate layers indicates the subhorizontal stratification and vertical divisibility of the Earth’s crust. Deformations of the deep layers are compared with the latest near-surface platform, which revealed a connection between near-surface and deep deformations and indicated that the deep deformations are the latest ones. This study is relevant for solving fundamental problems on the origin of the latest structures and a number of practical problems.
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