Structural and magnetic dimers in the spin-gapped system CuTe2O5

We investigated the magnetic properties of the system CuTe2O5 by susceptibility and electron spin resonance measurements. The anisotropy of the effective g-factors and the ESR linewidth indicates that the anticipated structural dimer does not correspond to the singlet-forming magnetic dimer. Moreover, the spin susceptibility of CuTe2O5 can only be described by taking into account interdimer interactions of the same order of magnitude than the intradimer coupling. Analyzing the exchange couplings in the system we identify the strongest magnetic coupling between two Cu ions to be mediated by super-super exchange interaction via a bridging Te ligand, while the superexchange coupling between the Cu ions of the structural dimer only results in the second strongest coupling

The valuable characteristics of oats genotypes and resistance to Fusarium disease

A comprehensive field- and laboratory-based assessment of the eco-geographical and intraspecific diversity of oats helps determine the parameters, on the basis of which it is possible to select genotypes that may serve as genetic sources for breeding. The study aims to analyze the relationship of agronomic traits of oat genotypes from the VIR collection with resistance to Fusarium disease. The agronomic characters and disease resistance of 340 genotypes of hulled and naked oats belonging to the cultivated species Avena sativa L., A. byzantina C. Koch, A. abyssinica Hoch. and A. strigosa Schreb. of different geographical origin have been tested in field and laboratory conditions in 2007–2009 and in 2014. The artificial infection with Fusarium sporotrichioides Sherb. was used to evaluate bacterial loads and mycotoxin contamination in the oat genotypes. An integral analysis has shown that the duration of the second half of the vegetation period, resistance to lodging and pathogen infection, plant height and panicle elongation facilitate grain infection. It has been found that A. strigosa and A. sativa are less susceptible to Fusarium than A. byzantina and A. abyssinica. Naked oats are more resistant to Fusarium disease if compared to the hulled ones. A comparison of evaluation results for the local and bred genotypes has shown that local accessions with the unilateral panicle and dark-colored floral glumes are more resistant to Fusarium disease. When considering the geographical origin, a higher degree of resistance was discovered in local varieties from China as well as in some accessions from Russia and USA and bred cultivars from Belarus. In total, the characters studied made it possible to identify oat genotypes with high yield and resistance to Fusarium disease

Viability of black currant pollen before and after cryopreservation in liquid nitrogen, and its morphological features

Background. Learning about morphological and biological features of pollen is very important to make correct estimations of plant productivity and breeding efficiency.Materials and methods. The viability of black currant pollen was analyzed in 2019 at the Laboratory for Long-Term Storage of Plant Genetic Resources, N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR). Eleven black currant cultivars of various ecogeographic and genetic origin maintained at Pushkin and Pavlovsk Laboratories of VIR served as the material for the research. Pollen viability was tested on an artificial medium with 10% sucrose and 0.8% agar. Morphological studies were carried out using light and confocal laser scanning microscopy at the Palynology Laboratory and the Core Centrum of Cell and Molecular Technologies in Plant Science housed by the Komarov Botanical Institute (BIN).Results and conclusion. The prevailing adverse weather conditions in 2019 produced a negative impact on the process of male generative structure formation. The level of pollen viability, depending on the cultivar, ranged from 17.98 to 58.60%. After exposure to liquid nitrogen (–196°C) for 6 months, the number of germinated pollen grains increased 1.1 to 3.2 times in all the studied cultivars, except one (‘Pozdnyaya poslevoennaya’, k-7652). A palynomorphological study revealed that reduced pollen viability in some cultivars (‘Krasnoyarskaya 1018’, k-7607; ‘Tsema’, k-25900; ‘Pozdnyaya poslevoennaya’, k-7652) was associated with morphological deviations in the sporoderm structure (small pollen grains, exine thickening and formation of verrucate mesoporium surfaces). A low positive correlation was observed between the level of pollen viability and the diameters of the pore (r = 0.43) and pollen grain (r = 0.27). An insignificant negative correlation was apparent between the level of viability and the exine thickness (r = –0.33)

Callus formation ability in cultivated peanuts (<i>Arachis hypogaea</i> L.)

Background: Russia is one of the largest peanut importing countries. At the same time, in the south of the country, several zones meet the requirements for peanut cultivation. It is possible to increase the yield of the existing peanut varieties by using modern biotechnology methods, in particular agrobacterial transformation. It is known from the literature data that different peanut genotypes and explants from various sources react differently to in vitro regeneration. Successful regeneration depends on the correct protocol, including both the type of regeneration and the composition of media promoting growth and in vitro induction.Objectives: a technique for obtaining peanut regenerants in in vitro culture.Materials and methods: Eight peanut accessions from the VIR collection of different origin were used in the work. Embryonic explants were grown on Murashige-Skoog medium supplemented with the hormone 2,4-dichlorophenoxyacetic acid (2,4-D).Results and conclusions: As a result of assessing the regenerative ability of peanuts grown on Murashige-Skoog medium with the hormone 2,4-D at a concentration of 2 g/L, differences in the callus formation ability were revealed in different accessions. Those with catalog numbers k-793, k-2054 and k-2055 did not form organogenic calli, while accessions k-698 and k-1987 showed the highest percentage of callus formation from embryonic explants

The trait-specific collection of large-seeded sunflower at VIR: ba source for breeding cultivars and hybrids

Background. In recent years, an increase has been observed in the share of sunflower seeds in the confectionery and food industries. There are 30 cultivars and only 3 hybrids for confectionery use among 839 zoned sunflower cultivars and hybrids listed in the State Register for Selection Achievements Admitted for Usage in 2023. Thus, the development of source material for breeding large-seeded cultivars and hybrids remains a relevant task.Materials and methods. The studied material included 90 accessions selected for their large seed size from VIR’s sunflower collection. The following characters were assessed: 1000 seed weight, days from sprouting to maturation, plant height, head diameter, cypsela color and size, and resistance to downy mildew. DNA markers were used to identify accessions with the Rf1 gene and CMS.Results. Accessions k-2818 (Primorsky Territory), k-3633, k-3748, k-3782 (China), and k-3578 (Ukraine) were the best in 1000 seed weight. Russian cvs. ‘Alekseyevsky Krupnoplodny 2’ (k-3552), ‘Gyar-Gyar’ (k-1589), ‘SPK’ (k-3426), and ‘Lakomka’ (k-3526) confirmed their large seed size. The sterile type of cytoplasm was identified in 12 accessions. Fourteen accessions with fertile cytoplasm had diagnostic markers of the nuclear Rf1 gene.Conclusion. The large-seeded cultivars developed at VNIIMK, ‘SPK’, ‘Lakomka’, and k-3782 from China were the best not only in their large seed size but also in downy mildew resistance. As a result of long-term studies, a trait-specific collection was established for the large seed size trait. It included 90 accessions that can be used in the development of confectionery cultivars. Large-seeded sunflower accessions carrying the Rf1 gene were identified. Some of them became the ancestors of donor lines for both pollen fertility restoration genes and large seed size

Биоэтические аспекты совершенствования производства антирабического иммуноглобулина в России

The main objective of the present research was to review the studies that look into ways of improving production of anti-rabies immunoglobulin in terms of bioethical principles: ensuring patients’ right to receive quality pharmaceutical care, and compliance with the 3R principles. At the same time, compliance with bioethical principles should contribute to the improvement of production technology and the product quality, which is especially important for antirabies immunoglobulin due to the existing high demand for it. The paper analyses the current trends in avoidance of animal use in the production of rabies immunoglobulin. It summarises the main methods of production of serum products for post-exposure prophylaxis of rabies. The example of heterologous rabies immunoglobulin is used to substantiate the need to improve quality control of drugs by following the 3R principles. The paper highlights the potential use of cell cultures for determination of rabies immunoglobulin specific activity. The authors formulated the objectives that include development and use of pyrogen detection methods which do not involve animal use and are consistent with the current pharmacopoeial standards. They assessed the possibility and feasibility of removing Abnormal Toxicity Test for heterologous rabies immunoglobulin in accordance with the current international trends. The formulated objectives imply optimisation of production of heterologous rabies immunoglobulin in Russia in order to improve the quality of antirabies measures. The objectives include higher production volumes to ensure the availability of the product to patients, reduction of the product reactogenicity by using cell-culture technologies for obtaining rabies antigen, as well as development and implementation of in vitro test methods for product quality control in terms of Specific activity, Pyrogenicity, and Abnormal toxicityОсновной целью работы явилась оценка исследований, направленных на развитие производства антирабического иммуноглобулина, с точки зрения биоэтических принципов: обеспечение права пациента на получение качественной фармацевтической помощи и соответствия концепции 3R. При этом следование биоэтическим принципам должно способствовать совершенствованию технологии производства и повышению качества лекарственного средства, что особенно актуально в отношении препарата антирабического иммуноглобулина вследствие его высокой востребованности. В статье проведен анализ современных тенденций по исключению животных в технологии производства антирабического иммуноглобулина. Показаны основные современные направления получения сывороточных препаратов для постэкспозиционной профилактики бешенства. На примере препарата гетерологичного антирабического иммуноглобулина обоснована необходимость совершенствования контроля качества лекарственных средств путем следования принципам 3R. Показан потенциал применения клеточных культур при определении специфической активности антирабического иммуноглобулина. Определены задачи по разработке и применению методов контроля содержания пирогенных примесей без использования животных в соответствии с актуальными фармакопейными документами. Проведена оценка возможности и целесообразности исключения показателя «Аномальная токсичность» в отношении гетерологичного антирабического иммуноглобулина в соответствии с современными международными тенденциями. Определены задачи совершенствования российского производства гетерологичного антирабического иммуноглобулина, направленные на улучшение качества обеспечения антирабической помощи, включающие увеличение объемов производства для обеспечения доступности препарата пациентам, снижение реактогенности препарата за счет получения рабического антигена с применением культуральных технологий, а также разработку и внедрение методов in vitro для проведения контрольных исследований качества препарата по показателям «Специфическая активность», «Пирогенность», «Аномальная токсичность»

Lines resistant to downy mildew in the sunflower genetic collection at VIR

Background. Downy mildew (DM) caused by the fungus Plasmopara halstedii (Farl) Berl. &amp; De Toni) is one of the most harmful diseases of sunflower (Helianthus annuus L.). Due to the pathogen’s attacks, annual seed harvest losses range between 30% and 70%. Lines resistant to new races of the pathogen should be obtained for the development of commercial sunflower hybrids.Materials and methods. Downy mildew resistance of 323 lines and 10 cultivars from the sunflower collection was assessed in the field at the Kuban Experiment Station of VIR in 2017–2018. Line VIR 845, susceptible during all years of observations, was used as a control. Resistance genes were identified by means of the molecular analysis using diagnostic markers of the Plarg, Pl6 and Pl8 genes that confer resistance to many known P. halstedii races.Results. The founder varieties of VIR’s lines were susceptible to a varying extent. Thirty-nine lines were resistant in 2016 and 2018; among those, 36 lines were susceptible in 2017. Presumably, a more virulent P. halstedii race became widespread in 2017, compared to the races that prevailed in 2016 and 2018, so the genes that determined resistance in 2016 and 2018 turned out to be ineffective. Lines ТА 716-18, VIR 768, and VIR 800, having originated from interspecific hybrids, exhibited absence of pathogenic damage during 3 years of the trials. Molecular markers of the Plarg, Pl6 and Pl8 genes were detected in most lines that demonstrated resistance in 2016 and 2018. There were no markers in lines VIR 768 and VIR 800, whereas in ТА 716-18 the markers of Plarg and Pl8 were present.Conclusion. As a result of the long-term studies, a trait-specific genetic collection was established for sunflower. It comprises genotyped lines with various effective DM resistance genes. Lines ТА 716-18, VIR 768 and VIR 800 appeared highly resistant to the pathogen and probably possess new resistance genes/alleles introgressed from wild species

The crystal growth and properties of novel magnetic double molybdate RbFe5_{5}(MoO4_{4})7_{7} with mixed Fe3+^{3+}/Fe2+^{2+}states and 1D negative thermal expansion

Single crystals of new compound RbFe$_5$(MoO$_4$)$_7$ were successfully grown by the flux method, and their crystal structure was determined using the X-ray single-crystal diffraction technique. The XRD analysis showed that the compound crystallizes in the monoclinic space group P21/m, with unit cell parameters a = 6.8987(4), b = 21.2912(12) and c = 8.6833(5) Å, β = 102.1896(18)°, V = 1246.66(12) Å$^3$, Z (molecule number in the unit cell) = 2, R-factor (reliability factor) = 0.0166, and T = 293(2) K. Raman spectra were collected on the single crystal to show the local symmetry of MoO$_4$ tetrahedra, after the confirmation of crystal composition using energy dispersive X-ray spectroscopy (EDS). The polycrystalline samples were synthesized by a solid-state reaction in the Ar atmosphere; the particle size and thermal stability were investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) analyses. The compound decomposes above 1073 K in an Ar atmosphere with the formation of Fe(III) molybdate. The thermal expansion coefficient along the c direction has the value α = −1.3 ppm K$^{−1}$ over the temperature range of 298–473 K. Magnetic measurements revealed two maxima in the magnetization below 20 K, and paramagnetic behavior above 50 K with the calculated paramagnetic moment of 12.7 μB per formula unit is in good agreement with the presence of $_3$Fe$^{3+}$ and $_2$Fe$^{3+}$ in the high-spin (HS) state. The electronic structure of RbFe5(MoO4)7 is comparatively evaluated using X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations