It has been shown that spontaneous release of non-covalent flavins (from flavoenzymes) begins after isolation of mitochondria from rat liver, which is hydrolyzed to riboflavin. This process is ...stopped by 1 mM EDTA in the incubation medium. In the presence of NADH, deflavinization of flavoproteins leads to formation of superoxide by at least of three processes. The first of these occurs in complex I as a result of the spontaneous release of FMN from the active center. This process is inhibited by adenosine and guanosine phosphates, as well as NAD, but amplified by nicotinamide. The second process is associated with enzymatic hydrolysis of FAD and FMN to riboflavin; it is blocked by EDTA, AMP, NA, NAD. The third process is associated with non-enzymatic hydrolysis of FAD by iron ions in matrix; it is blocked by EDTA and AMP.
•Mitochondrial flavins are released from flavoenzymes and subsequent hydrolysed with riboflavin formation after isolation of mitochondria.•The process cleavage of free FAD and FMN occurs by enzymes and non-enzymatically by iron ions.•The resulting free riboflavin interacts with NADH non-enzymatically, producing superoxide (under dark conditions).•This process is blocked by EDTA, AMP and NAD.•The release of FMN is prevented by AMP, GMP, NAD and is accelerated by nicotinamide.
The results of a study of the distribution of eggs of Baikal omul
Coregonus migratorius
in a large foothill watercourse in Siberia in 1935–2022 are presented. The distanse of omul spawning migration ...in the Selenga River (some of the migration parameters are taken into account since 1920) depends on a certain combination of abiotic environmental factors, biological parameters of spawners, timing of entry into the river, and the number of their spawning herd. The distance of migration has a high inverse correlation with the degree of maturity of the spawners, which is expressed by the maturity index of omul females, as well as with the timing of herd entry into the river and water consumption at the beginning of migration (September). The higher the maturity of the reproductive products of spawners, the shorter the migration route, and vice versa. In addition, the maturity of spawners also determines the timing (date) of stock entry into the river: less mature individuals enter the river earlier and are distributed at spawning grounds higher upstream, while more mature individuals enter the river later and spawn downstream of the river. The distance of omul spawning migration increases during a decrease in the water flow of the Selenga River in September and, on the contrary, decreases with increase in water flow. Finally, The distance of the spawning route of omul in Selenga is determined by the size of the spawning herd: the higher the number of spawners, the more area they need for spawning and the longer their spawning route. Water temperature does not influence the length of omul spawning migration. The spawning run takes place against the background of a decrease in water temperature in the river.
The thermal state of the northern rivers of Russia has undergone significant changes in the last 30–40 years due to climate warming, changes in water runoff. The purpose of this investigation is to ...study and explain only changes in heat flux, their long-term and spatial patterns in the northeast Asian part of Russia. Here, the heat flux of rivers is formed under the influence of climatic conditions, the altitude and latitude location of rivers, continuous permafrost, aufeis, glacial runoff and groundwater recharge, different water regime of rivers. An important feature of the research is the use of a large number of hydrological stations—145 and 231 gauging stations with data on water discharge and stream temperature, mainly from 1955 to 2012/2018. The abundance of data enabled to create unique maps of heat-flux and its deviations from the values of the base period. Empirical relationships between heat flux, on the one hand, and water runoff and water temperature, on the other, made it possible to improve the initial data, showed the leading role of water runoff in long-term fluctuations in heat-flux. However, climatic warming enhances the role of the temperature factor and transforms the relationship between water runoff and heat-flux, “shifting” them upwards. So far, these violations have not covered most of the gauging stations. The long-term “behavior” of heat flux is not unambiguous. Nevertheless, the period since the late 1980s is distinguished by higher values of heat flux. 20% of gauging stations demonstrate an increase in heat, compared to the previous period, by 10, 39% demonstrate an increase from 10 to 25%, 36% demonstrate >25%. Since the mid-second half of the 2000s, the heat flux of the rivers in the western part of the region has signs of stabilization and even a decrease. The reason is low water flow. A violation of the stationarity of the series in terms of dispersion (
F
-test) was found at 30% stations with reliable and long-term observations, mainly in the eastern part. Further changes in the heat flux of the regional rivers will depend on both changes in the river water flow and temperature. Within a year, almost all annual heat flux (90–95%) is generated in the summer months and has peaks in June and July. In the Vilyuy River basin, in the upper and middle part of the Kolyma River basin and on the coast of the Sea of Okhotsk, the proportion of summer months decreases to 65–90%. In addition to estimation of heat flux at the hydrological stations, the inflow of river waters into the mouths of the main rivers of the region and, in general, into the Arctic seas was assessed in various ways.
The thermal state of the northern rivers of Russia has significantly changed during the last 30–40 years due to climate warming and changes in water runoff. The purpose of this study is to ...investigate and analyse these changes, their long-term and spatial patterns. In the northeast Asian part of Russia, including Chukotka, the northern districts of Yakutia and the Magadan Region, the thermal state of rivers is affected by cold climatic conditions, high altitudes, continuous permafrost, aufeis, glacial runoff and groundwater recharge. It is closely related to flow direction and dimension of rivers. The study uses dataset containing observations of river water temperature (mainly from 1955 to 2012/2018) at 231 gauging stations and records of 34 weather stations. The large dataset enabled to create seasonal and monthly air temperature maps, as well as maps of deviation of these parameters from the values of background period. The boundaries of ten altitude-thermal zones were set and for each zone a relationship between temperature and mean catchment height was established. Empirical relationships between water and air temperatures showed the leading role of air temperature in changes in stream temperature. It was found that, despite the huge size of the northeastern region and contrasting natural conditions, noticeable climatic warming (by 1–2°C) has been recorded almost at the same time (since 1988). To the east of the Indigirka River, it has been detected since the mid-1990s. The air temperatures increase in spring and autumn is higher than in summer when the main river heat-flux is generated. The beginning of the first noticeable increase in stream temperatures dates back to the late 1980s. The next time milestones were the mid-late 1990s, the first half of the 2000s (from the Indigirka River to the Anadyr River), the late 2000s–early 2010s (western part of the region). The rivers and territories with positive water temperature anomalies predominate. The average range of anomalies is from ‒0.2 to +1.5°C; extreme values are from ‒0.8 to +2°C. The Arctic rivers, the area at the intersection of the Vilyuy and Olenek river basins, and the rivers to the east of the Kolyma River have maximum positive water temperature anomalies. Observed trends create favorable conditions for the intensification of thermal erosion and an increase in turbidity of river water.
The change in phytoplankton along the length of the Ural River from Verkhneuralsk to Orenburg (on a site of more than 1000 km) has been studied for the first time. The powerful eutrophying effect of ...Magnitogorsk on the river for more than 150 km has been revealed. It manifests itself in the fact that the phytoplankton biomass in this area increases greatly, averaging about 15 mg/L (with the dominance of cyanobacteria
Microcystis aeruginosa
), whereas the species diversity index (Shannon index), on the contrary, reaches extremely low values of 0.25. This indicates a significant oppression of the plankton community and deterioration of water quality. In the Ural River above this site (from Verkhneuralsk to Magnitogorsk reservoir), as well as below it (from Orsk to Orenburg), phytoplankton indicators correspond to the usual values of 1.6–1.7 mg/L of biomass, with a Shannon index of 3.3–3.5 (on average for each site). This suggests that the conditions for the existence of plankton in the upper and lower areas are favorable. At the same time, the sites differ in the composition of algae: the first is dominated by diatoms and the second is mainly dominated by green algae. This may be due to geographical factors: in the north, the Ural River flows in the forest-steppe zone, and in the south it flows in the steppe.
The present-day dynamics of maximal water levels was evaluated, and space and time variations of level excess during unfavorable and hazardous events in North Caucasian rivers were analyzed. The ...study was based on data from 59 hydrological gages over period 1961–2017. The mathematical expectation of maximal water levels was found to increase everywhere from 1961–1990 to 1991–2017, and the increase in the variance was also a dominating trend in North Caucasian rivers. In the period under consideration, water levels of unfavorable and hazardous phenomena were exceeded by maximal water levels on the average in 19.3 and 10.6% cases, respectively. At some sections, this characteristic reached 93.2 and 88.6%, respectively. The marks of unfavorable and hazardous phenomena in the Kuban basin and in rivers of the Caucasian Black Sea coast was found to increase between 1961–1990 and 1991–2017. In rivers in the Terek and Kuma basins, the numbers of gages where the marks of unfavorable phenomena increased or decreased were the same; however, from 1961–1990 to 1991–2017, dominating are gages with a tendency toward a decrease in the number of cases with levels above the marks of hazardous phenomena.
In the Russian climate, the security of populations and economic security are often limited by dangerous ice phenomena. Not only ice-jam floods, but also some processes lead to the violation of ...operating conditions of various facilities (water intakes, roads, bridges) and damage hydraulic structures and shipping. Currently, rivers’ ice regime characteristics change under the influence of both natural (primarily climatic) and anthropogenic factors. Changes have been analyzed in detail on the basis of observations of 300 hydrological stations in the period from 1936 to 2013. Changes of ice phenomena hazards have been estimated. Hazard assessment of flooding caused by ice jams has been carried out for the Northern Dvina River reach from the Velikiy Ustyug City to Kotlas, the most problematic ice jam flooding area in European Russia. The modeling was performed on the basis of
STREAM_2D
software complex for current conditions and taking into account the possible construction of various protective structures. Methods for the prevention of negative impact of water at the site are examined.
When processing animals and birds in the form of by-products, a fairly large amount of keratin-containing waste (horns, hooves, hair, wool, fluff and feather) was formed. In secondary poultry ...evisceration products, almost 80% of the protein is found in feather-down raw materials, so solving the problem of converting pen keratin into a digestible form is more important from the point of view of mobilization of native protein reserves and environmental problems. To produce a high-quality feed product, which preserves the biological value of the raw materials as much as possible, it is necessary to minimize the time of heat treatment. At the same time, it is desirable to use cost-effective and environmentally friendly technologies. The latest biological waste recycling techniques that meet these requirements include extrusion technologies. The article proposes the technology of obtaining a forage protein supplement, which can completely replace fish flour in the diet without reducing the zootechnical and feasibility indicators of growing poultry, valuable species of fish and furry animals. The main advantage is that none of the existing technologies in the world without rigorous chemical treatment is not able to bring the digestion of keratin of feather raw materials to 85-90 % in 1.5 minutes of processing with maximum preservation of the most valuable amino acids. We presented the results of the production check on the effectiveness of feeding extruded feed with feed additive from keratin-containing waste for fish, providing a significant increase in body weight growth and improvement of meat.
The Kolyma is the largest river, the basin of which lies entirely in the zone of continuous permafrost and is subject to considerable climate changes, which affects its hydrological regime. The ...current dynamics of water flow and runoff-formation factors over 1979–2020 are analyzed, and the sensitivity of water regime characteristics of the Kolyma River to changes in climate parameters is studied. The comparison of the mean values of meteorological characteristics in the Kolyma basin over 2000–2020 with the mean values over 1979–1999 showed an increase in the normal annual air temperature by 1.3°C, the total annual precipitation increased by 8.3% with the most abrupt increase in September and March. According to observation data, the annual river runoff at the Kolymskoe gage (283 km from the Kolyma mouth), increased by 5.2%. Physical-mathematical models of river runoff formation have gained in popularity as a tool for studying the features of the water regime and its dynamics. In this study, the ECOMAG model is applied to the Kolyma R. basin, where its calibration and verification for two gages showed a good reproducibility of the actual water discharges. To better understand the mechanisms of the response of Kolyma water regime to changes in the climate characteristics based on ECOMAG model, the sensitivity of runoff characteristics to air temperature and precipitation was analyzed.
The Republic of Kalmykia is located in the northwestern part of the Caspian Region and belongs to arid regions. The issue of water resources availability is extremely relevant here. Groundwater plays ...an important role in this aspect as a main and often the only source of drinking water supply. However, its use is limited because of its low natural quality. An approach to an increase in the operational groundwater reserves is its artificial replenishment. The Russian Research Institute for Integrated Use and Protection of Water Resources in 2020–2021 studied the possibility of replenishing water resources of subsurface water bodies in the Republic of Kalmykia by the accumulation of surface water. The results of the studies suggested a conclusion that the artificial replenishment of groundwater in the territory of the Republic of Kalmykia is inexpedient, because even in years with the surface runoff volume with 50% exceedance probability, the volume of surface runoff will be not enough for freshening groundwater within a year to the standard level (TDS ≤1.0 g/dm
3
). The formation of a permanent freshwater lens (the presence of which is of particular importance in dry years) in an aquifer within the system including infiltration basin and water well is impossible because its full drawdown will take place every year.
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