Impact of agricultural land use on distribution of microbial biomass and activity within soil aggregates

The presence of aggregates of various sizes in the soil is an important condition for soil carbon sequestration. In this system, microbial biomass is a key link. This work was devoted to the study of the influence of land use systems on the distribution of SOС, MB-SIR, microbial activity and eco-physiological indices (qCO₂, QR, MB-SIR/SOС and qCO₂/SOС) in relation to the size of soil aggregates. The distribution of SOС, MB-SIR and mineralization activity among the aggregates was heterogeneous. In the soil of crop rotation, high mineralization activity and MB-SIR were found in the aggregates 0.5–0.1 mm, in the monoculture soil in aggregates <0.1 mm and in the control soil in the aggregates 1–0.25 mm. There was a general trend towards a decrease in microbial activity, MB-SIR and SOС availability with an increase in aggregate size. In agricultural soils, microbial activity was determined by large aggregates (>5 mm), while in the control soil, by the aggregates 5–1 mm. Depending on the type of site and the size of aggregates, the differences in microbial metabolism were revealed. The qCO₂ and QR values decreased, and the MB-SIR/SOС and qCO₂/SOС increased in the series: control soil > crop rotation > monoculture. In the control soil, the values of the eco-physiological indices decreased with decreasing aggregate size. And vice versa, in agricultural soils, these parameters were the highest in the microaggregates (<0.25 mm). The monoculture soil, in contrast to the control soil and crop rotation soil, turned out to be more energy efficient.     

Design of new α-conotoxins: from computer modeling to synthesis of potent cholinergic compounds

A series of 14 new analogs of α-conotoxin PnIA Conus pennaceus was synthesized and tested for binding to the human α7 nicotinic acetylcholine receptor (nAChR) and acetylcholine-binding proteins (AChBP) Lymnaea stagnalis and Aplysia californica. Based on computer modeling and the X-ray structure of the A. californica AChBP complex with the PnIA[A10L, D14K] analog, single and multiple amino acid substitutions were introduced in α-conotoxin PnIA aimed at compounds of higher affinity and selectivity. Three analogs, PnIA[L5H], PnIA[A10L, D14K] and PnIA[L5R, A10L, D14R], have high affinities for AChBPs or α7 nAChR, as found in competition with radioiodinated α-bungarotoxin. That is why we prepared radioiodinated derivatives of these α-conotoxins, demonstrated their specific binding and found that among the tested synthetic analogs, most had almost 10-fold higher affinity in competition with radioactive α-conotoxins as compared to competition with radioactive α-bungarotoxin. Thus, radioiodinated α-conotoxins are a more sensitive tool for checking the activity of novel α-conotoxins and other compounds quickly dissociating from the receptor complexes.     

Flood effect on CH4 emission from the alas in Central Yakutia,East Siberia

During four years (2006–2009), methane (CH₄) emission was measured at different biomes (dry, wet grasslands, lake and lake vegetation) of mature thermokarst depression located at the most typical thermokarst terrain on the east bank of the Lena River, Central Yakutia, Russia (62°08′N, 130°30′E). To estimate total CH₄ emission from the whole thermokarst depression ecosystem, CH₄ emissions via plant bodies and ebullition were measured in addition to diffusive CH₄ flux measurement. The lake area increased twice from 20.4 ha in 2006 to 43.3 ha in 2007 and then did not change significantly in 2008 and 2009 (46.5 and 44.4 ha, respectively). Ebullition was considered to be a minor source for CH₄ emission from the lake in the studied thermokarst depression. CH₄ emissions from the lake water surface and via the plant body of lake vegetation (hygrophyte and hydrophyte vegetation) were the main sources of CH₄ and these increased by flooding both CH₄ emission rate and area. Using spatial changes of these biomes, the annual emission of CH₄ was calculated taking into account different sources of CH₄. Total CH₄ emission from the studied alas (63.7 ha) was 5.7, 5.2, 20.1 and 50.1 Mg carbon (C) in 2006–2009, respectively, and its difference during this period reached about 10 times. An extreme increase in CH₄ emission from the lake occurred in the second year of continuous flooding (2008), which might have been caused by the decomposition of flooded organic C. So, the lake water ecosystem is the main source of CH₄ in thermokarst depression controlled by the duration of flooding. Under future global climate change, thermokarst depressions in Central Yakutia have potential for lake expansion, causing significant increase in CH₄ emission in the studied region.     

International Winter Wheat Improvement Program: history,activities, impact and future

International Winter Wheat Improvement Program (IWWIP) was established in 1986 between the Government of Turkey and CIMMYT with three main objectives: (1) develop winter/facultative germplasm for Central and West Asia, (2) facilitate global winter wheat germplasm exchange, and (3) training wheat scientists. ICARDA joined the program in 1991 making it a three-way partnership that continues to work effectively. The germplasm developed by IWWIP as well as the winter wheat cultivars and lines received from global cooperators are assembled into international nurseries. These nurseries are offered annually to public and private entities (IWWIP website) and distributed to more than 100 cooperators in all continents. IWWIP impact has primarily been in new winter wheat cultivars combining broad adaptation, high yield potential, drought tolerance and disease resistance. A total of 93 IWWIP cultivars have been released in 11 countries occupying annually an estimated 2.5–3.0 Mha. IWWIP cooperation with researchers in Turkey, Central and West Asia and several US universities has resulted in a number of publications reviewed in this paper. Important IWWIP impacts include national inventories of wheat landraces in Turkey, Tajikistan and Uzbekistan, their collection, characterization, evaluation and utilization.     

Genome-wide association study reveals favorable alleles associated with common bunt resistance in synthetic hexaploid wheat

Genetic resistance to common bunt is a cost-effective, environmentally friendly, and sustainable approach to controlling the disease. To date, 16 race specific common bunt resistance genes (Bt1-Bt15 and Btp) have been reported in wheat. However, a limited number have been mapped and few markers have been identified, which limits the usage of molecular markers in a marker-assisted breeding program. A total of 125 synthetic hexaploid wheats (SHWs) were evaluated for reactions to a mixture of common bunt races under field conditions in Turkey in 2016 and 2017. The objectives of this study were to identify common bunt resistant genotypes, identify genomic regions conferring resistance to common bunt using 35,798 genotyping-by-sequencing derived single nucleotide polymorphisms (SNPs), and investigate the significant SNPs present within genes using the functional annotations of the underlying genes. We found 29 resistant SHWs that can be used in wheat breeding. The genome-wide association study identified 15 SNPs associated with common bunt resistance and a haplotype block comprising three SNPs in perfect linkage disequilibrium. Five of them were novel and were located on chromosomes 2A, 3D, and 4A. Furthermore, seven of the 15 SNPs were found within genes and had annotations suggesting potential role in disease resistance. This study identified several favorable alleles that decreased common bunt incidence up to 26% in SHWs. These resistant SHWs and candidate genomic regions controlling common bunt resistance will be useful for wheat genetic improvement and could assist in further understanding of the genetic architecture of common bunt resistance.     

The importance of dust material in urban soil formation: the experience on study of two young Technosols on dust depositions

Purpose

The volume of dust deposition on the soil surface in Moscow is big enough and make several tens of grams per square meter annually. The role of dust as a soil-forming material is especially high in places with practically no other soil parent materials. It is necessary to consider solid atmospheric precipitation as a parent soil material in urban conditions and its impact on soil properties.

Materials and methods

Samples of two soil bodies were taken near two major highways of Moscow, and airborne solid deposit samples were collected from the roadside barrier in summer and from plant leaves after snowmelt. The fallout samples were studied by methods used for soil because of its silicate matrix (Si～30 % total). Main complex characteristics of samples were obtained by chemical analysis and with a scanning electron microscope with energy-dispersive X-ray spectrometer. Bulk elemental composition, available phosphorus and potassium, carbonates, organic carbon and oil hydrocarbon contents, pH, redox potential, magnetic susceptibility, and particle-size distribution of dust and soils were determined.

Results and discussion

Near the highways, where the process of dust transfer is activated, there are possibilities of dust inclusion into soil and formation of new soil horizons on these deposits. Pedofeatures are formed during a very short period of time. The soil-forming processes are connected with both soil organic matter and mineral compound transformation. Chemical properties of the studied soils correspond to those of usual Moscow soil horizons and dust samples studied previously by Prokofyeva et al. (2011) and Prokof’eva et al. (2015). It was established that atmospheric solid aerosol imports organic carbon, carbonates, and other salts; pollutants such as oil hydrocarbons; and heavy metals into the soil. Airborne deposits influence soil physical properties by enriching the soil with clay and coarse silt fractions.

Conclusions

Investigation of dust deposit composition provides data for characterizing material being continuously deposited on the urban soil surface. The atmospheric fallouts together with construction waste and natural rocks provide the common geochemical properties of urban soils.

     

Synthesis of the Oligosaccharides Related to Branching Sites of Fucosylated Chondroitin Sulfates from Sea Cucumbers

Natural anionic polysaccharides fucosylated chondroitin sulfates (FCS) from sea cucumbers attract great attention nowadays due to their ability to influence various biological processes, such as blood coagulation, thrombosis, angiogenesis, inflammation, bacterial and viral adhesion. To determine pharmacophore fragments in FCS we have started systematic synthesis of oligosaccharides with well-defined structure related to various fragments of these polysaccharides. In this communication, the synthesis of non-sulfated and selectively O-sulfated di- and trisaccharides structurally related to branching sites of FCS is described. The target compounds are built up of propyl β-d-glucuronic acid residue bearing at O-3 α-l-fucosyl or α-l-fucosyl-(1→3)-α-l-fucosyl substituents. O-Sulfation pattern in the fucose units of the synthetic targets was selected according to the known to date holothurian FCS structures. Stereospecific α-glycoside bond formation was achieved using 2-O-benzyl-3,4-di-O-chloroacetyl-α-l-fucosyl trichloroacetimidate as a donor. Stereochemical outcome of the glycosylation was explained by the remote participation of the chloroacetyl groups with the formation of the stabilized glycosyl cations, which could be attacked by the glycosyl acceptor only from the α-side. The experimental results were in good agreement with the SCF/MP2 calculated energies of such participation. The synthesized oligosaccharides are regarded as model compounds for the determination of a structure-activity relationship in FCS.     

Impact of soil organic matter on calcium carbonate equilibrium and forms of Pb in water extracts from Kastanozem complex

Purpose

Accounting for ionic strength and ion association, the degree of calculated supersaturation with CaCO₃ of gleyic solonetz and molic solonetz soil solution is high. The purpose of the research was to reveal the effect of the water-dissolved organic matter (DOM) on the calcium carbonate equilibrium (CCE) in soil solution, to create a thermodynamic model of carbonate association and complexation with DOM and heavy metals (HMs), and to correct the principal of soil management.

Materials and methods

Object of research—Kastanozem complex of the dry steppe, Rostov Oblast, Russia. The water extraction of soluble salts was made at the water-to soil-ratio 5:1 and analyzed using standard methods. DOM content was determined by Strosser (J Agrobiol 27:49–60, 2010). The soil solution macro-ion equilibrium composition was calculated using ION-2 program (Endovitsky et al. 2009). DOM role in soil solution supersaturation with СаСО₃ was assessed, comparing C content in real solution and in identical artificial solution prepared without organic matter. Taking into account the ion association, the molar fractions of free and bound HM ion were calculated using microelement association coefficient, k_as(ME). The soil liquid-phase saturation with CaCO₃ was characterized by the ratio of the real solubility product (S) to the thermodynamic solubility product (S⁰): К?=?S/S⁰.

Results and discussion

The soil solution supersaturation with CaCO₃ was characterized by the product of analytical concentrations (S), equilibrium concentrations [accounting ion activity (S^I), ion association (S^II), ion association and complexation (S^III)], and the thermodynamic solubility product (S⁰). To evaluate the role of DOM in soil solution supersaturation with CaCO₃, the initial pure Ca (HCO₃)₂ solution series was prepared. The humic and fulvic acids from the illuvial horizon of gleyic solonetz with concentrations of 20 mg C L^?1 and 120 mg C L^?1 decreased the CaCO₃ precipitation compared with initial soil solution. The release of CaCO₃ from soil water extracts containing water-soluble organic matter was 1.2–1.9 times less compared with identical artificial solution not containing organic matter. The HM binding by carbonates is proportional to the DOM content.

Conclusions

In molic solonetz and gleyic solonetz, the neutralization of the soda should be assessed by the soil solution supersaturation with CaCO₃. To calculate the degree of HM passivation in soil solution containing DOM, the coefficient of soil solution oversaturation with CaCO₃ is proposed. For reducing soil organic matter and DOM mobility and loss from soil, as well as for Pb passivation, intra-soil mechanical processing, intra-soil waste management, and intra-soil watering are proposed.

     

Circle of life: the common hamster (Cricetus cricetus) adaptations to the urban environment

Traditionally, urbanization has been seen as a negative phenomenon for biota. However, changes in the environmental parameters induced by urbanization might be favorable for some species. Over the past half‐century, the common hamster has actively populated cities, establishing populations in some European, Russian and Kazakhstan cities. Based on integrative methods, we investigated free‐range common hamsters inhabiting Simferopol from 2015 to 2018 to reveal possible adaptations to the urbanized environment across several parameters, including lifespan, hibernation period, reproductive activity and body mass. Results show that in urban areas, the common hamster demonstrates an extremely short hibernation period compared to other localities, possibly due to enhanced food resources from urban forestry (walnuts, locus and hazelnut), allowing the species to start breeding very early (February) and finish as late as October. We present the first evidence of polyandry for this species: mating of receptive females with several males and subsequent confirmation of multiple paternity. Despite high reproductive potential, the lifespan of the common hamster in urban conditions is generally very short (less than 1 year). We speculate that in the process of synurbization, the common hamster's innate plasticity across many life history traits permits it to successfully colonize throughout a wide range of habitats, with the ability to form novel adaptations to urban environments.