Combination Breeding and Marker-Assisted Selection to Develop Late Blight Resistant Potato Cultivars

(1) Background: Although resistance to pathogens and pests has been researched in many potato cultivars and breeding lines with DNA markers, there is scarce evidence as to the efficiency of the marker-assisted selection (MAS) for these traits when applied at the early stages of breeding. A goal of this study was to estimate the potential of affordable DNA markers to track resistance genes that are effective against the pathogen Phytophthora infestans (Rpi genes), as a practical breeding tool on a progeny of 68 clones derived from a cross between the cultivar Sudarynya and the hybrid 13/11-09. (2) Methods: this population was studied for four years to elucidate the distribution of late blight (LB) resistance and other agronomical desirable or simple to phenotype traits such as tuber and flower pigmentation, yield capacity and structure. LB resistance was phenotypically evaluated following natural and artificial infection and the presence/absence of nine Rpi genes was assessed with 11 sequence-characterized amplified region (SCAR) markers. To validate this analysis, the profile of Rpi genes in the 13/11-09 parent was established using diagnostic resistance gene enrichment sequencing (dRenSeq) as a gold standard. (3) Results: at the early stages of a breeding program, when screening the segregation of F1 offspring, MAS can halve the workload and selected SCAR markers for Rpi genes provide useful tools

The Structure of Carbon Gels Obtained by Carbonization of Organic Xerogels Based on Larch Bark Tannins and Pine Cellulose

Впервые предложено получать углеродные гели путем карбонизации органических гелей, синтезированных золь-гель конденсацией формальдегида с таннинами коры лиственницы и целлюлозой сосны. По данным метода БЭТ, введение целлюлозы в состав органического таннин-формальдегидного геля меняет такие характеристики пористой структуры получаемых углеродных гелей, как удельная поверхность, общий объем пор, удельная поверхность микропор, объем микропор, объем мезопор, средний диаметр пор. Развитие пористой структуры углеродных гелей, полученных с использованием добавок растворенной целлюлозы (10 и 20 мас%), происходит в результате формирования мезопор со средним диаметром 22.83 и 21.54 нм. Введение порошка целлюлозного аэрогеля в исходный органический гель способствует формированию микропор в получаемом углеродном геле. Наиболее развитую микропористую структуру имеет углеродный гель, полученный карбонизацией органического таннин-целлюлозного геля, содержащего 20 мас% целлюлозного аэрогеля (удельная поверхность 754 м2/г, из них 80 % (606 м2/г) приходится на поверхность микропор). Методом сканирующей электронной микроскопии установлено, что морфологию поверхности углеродных гелей, получаемых карбонизацией органических таннин-целлюлозных гелей, можно регулировать путем вариации как концентрации целлюлозы, так и её состояния (раствор целлюлозы или порошок целлюлозного аэрогеля) при синтезе исходного органического геляFor the first time, it was proposed to obtain carbon gels by carbonization of organic gels synthesized by sol-gel condensation of formaldehyde with larch bark tannins and pine cellulose. According to the BET method, the introduction of cellulose into the composition of an organic tannin- formaldehyde gel changes such characteristics of the porous structure of the obtained carbon gels as specific surface area, total pore volume, micropore surface area, micro- and mesopore volume, and average pore diameter. The development of the porous structure of carbon gels obtained with the use of dissolved cellulose additives (10 and 20 wt%) occurs as a result of the formation of mesopores with an average diameter of 22.83 and 21.54 nm. The introduction of cellulose aerogel powder into the original organic gel promotes the formation of micropores in the resulting carbon gel. The most developed microporous structure has a carbon gel obtained by carbonization of an organic tannin-cellulose gel containing 20 wt% cellulose aerogel (specific surface 754 m2/g, of which 80 % (606 m2/g) relates to the surface of micropores). Using scanning electron microscopy, it was found that the surface morphology of carbon gels obtained by carbonization of organic tannin-cellulose gels may be controlled by varying both the concentration of cellulose and its state (cellulose solution or cellulose aerogel powder) during the synthesis of the initial organic ge

Diversity of Late Blight Resistance Genes in the VIR Potato Collection

Late blight (LB) caused by the oomycete Phytophthora infestans (Mont.) de Bary is the greatest threat to potato production worldwide. Current potato breeding for LB resistance heavily depends on the introduction of new genes for resistance to P. infestans (Rpi genes). Such genes have been discovered in highly diverse wild, primitive, and cultivated species of tuber-bearing potatoes (Solanum L. section Petota Dumort.) and introgressed into the elite potato cultivars by hybridization and transgenic complementation. Unfortunately, even the most resistant potato varieties have been overcome by LB due to the arrival of new pathogen strains and their rapid evolution. Therefore, novel sources for germplasm enhancement comprising the broad-spectrum Rpi genes are in high demand with breeders who aim to provide durable LB resistance. The Genbank of the N.I. Vavilov Institute of Plant Genetic Resources (VIR) in St. Petersburg harbors one of the world’s largest collections of potato and potato relatives. In this study, LB resistance was evaluated in a core selection representing 20 species of seven Petota series according to the Hawkes (1990) classification: Bulbocastana (Rydb.) Hawkes, Demissa Buk., Longipedicellata Buk., Maglia Bitt., Pinnatisecta (Rydb.) Hawkes, Tuberosa (Rydb.) Hawkes (wild and cultivated species), and Yungasensa Corr. LB resistance was assessed in 96 accessions representing 18 species in the laboratory test with detached leaves using a highly virulent and aggressive isolate of P. infestans. The Petota species notably differed in their LB resistance: S. bulbocastanum Dun., S. demissum Lindl., S. cardiophyllum Lindl., and S. berthaultii Hawkes stood out at a high frequency of resistant accessions (7–9 points on a 9-point scale). Well-established specific SCAR markers of ten Rpi genes—Rpi-R1, Rpi-R2/Rpi-blb3, Rpi-R3a, Rpi-R3b, Rpi-R8, Rpi-blb1/Rpi-sto1, Rpi-blb2, and Rpi-vnt1—were used to mine 117 accessions representing 20 species from seven Petota series. In particular, our evidence confirmed the diverse Rpi gene location in two American continents. The structural homologs of the Rpi-R2, Rpi-R3a, Rpi-R3b, and Rpi-R8 genes were found in the North American species other than S. demissum, the species that was the original source of these genes for early potato breeding, and in some cases, in the South American Tuberosa species. The Rpi-blb1/Rpi-sto1 orthologs from S. bulbocastanum and S. stoloniferum Schlechtd et Bché were restricted to genome B in the Mesoamerican series Bulbocastana, Pinnatisecta, and Longipedicellata. The structural homologs of the Rpi-vnt1 gene that were initially identified in the South American species S. venturii Hawkes and Hjert. were reported, for the first time, in the North American series of Petota species

Dithiocarbamates as Effective Reversible Addition–Fragmentation Chain Transfer Agents for Controlled Radical Polymerization of 1-Vinyl-1,2,4-triazole

Narrow dispersed poly(1-vinyl-1,2,4-triazole) (PVT) was synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization of 1-vinyl-1,2,4-triazole (VT). AIBN as the initiator and dithiocarbamates, xanthates, and trithiocarbonates as the chain transfer agents (CTA) were used. Dithiocarbamates proved to be the most efficient in VT polymerization. Gel permeation chromatography was used to determine the molecular weight distribution and polydispersity of the synthesized polymers. The presence of the CTA stabilizing and leaving groups in the PVT was confirmed by 1H and 13C NMR spectroscopy. The linear dependence of the degree of polymerization on time confirms the conduct of radical polymerization in a controlled mode. The VT conversion was over 98% and the PVT number average molecular weight ranged from 11 to 61 kDa. The polydispersity of the synthesized polymers reached 1.16. The occurrence of the controlled radical polymerization was confirmed by monitoring the degree of polymerization over time

Synthesis and Characterization of Silver-Containing Nanocomposites Based on 1-Vinyl-1,2,4-triazole and Acrylonitrile Copolymer

Insoluble silver-containing nanocomposites based on 1-vinyl-1,2,4-triazole and acrylonitrile copolymer was synthesized and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, atomic absorption, X-ray diffraction, and thermogravimetric data analysis. The silver content of the nanocomposites varied from 8.0 to 23.5% (the silver content depends on the ratio of the copolymer-silver salt). Synthesis of silver nanocomposites was carried out by thermal treatment of a polymer complex of copolymer-silver salt without the use of an additional reducing agent. X-ray diffraction was used to control the formation of silver nanoparticles at different temperatures (210°С, 220°С, and 250°С). Synthesis of nanocomposites shows a developed porous structure with a channel diameter in most cases of 1-4 microns. The EPR monitoring of the nanoparticle germination and growth reveals that the generation of the nanocomposites proceeds via a stage of complex formation between the polymeric matrix and silver ions. The synthesized nanocomposites possess paramagnetic properties and show a narrow EPR symmetric signal with the concentration of unpaired electrons of 1020 spin/g, a g-factor 2.0050, and signal width 5-6 Gs. Thermal stability of silver-containing nanocomposites is up to 270-320°C

Contamination of Hospital Surfaces with Bacterial Pathogens under the Current COVID-19 Outbreak

The SARS-CoV-2 pandemic remains a global health issue for several reasons, such as the low vaccination rates and a lack of developed herd immunity to the evolution of SARS-CoV-2, as well as its potential inclination to elude neutralizing antibodies. It should be noted that the severity of the COVID-19 disease is significantly affected by the presence of co-infections. Comorbid conditions are caused not only by pathogenic and opportunistic microorganisms but also by some representatives of the environmental microbiome. The presence of patients with moderate and severe forms of the disease in hospitals indicates the need for epidemiological monitoring of (1) bacterial pathogens circulating in hospitals, especially the ESKAPE group pathogens, and (2) the microbiome of various surfaces in hospitals. In our study, we used combined methods based on PCR and NGS sequencing, which are widely used for epidemiological monitoring. Through this approach, we identified the DNA of pathogenic bacteria (Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, CoNS, and Achromobacter spp.) on various surfaces. We also estimated the microbiome diversity of surfaces and identified the potential reservoirs of infections using 16S rRNA profiling. Although we did not assess the viability of identified microorganisms, our results indicate the possible risks of insufficient regular disinfection of surfaces, regardless of department, at the Infectious Diseases Hospital. Controlling the transmission of nosocomial diseases is critical to the successful treatment of COVID-19 patients, the rational use of antimicrobial drugs, and timely decontamination measures

Evaluation of the Safety and Toxicity of the Original Copper Nanocomposite Based on Poly-N-vinylimidazole

A new original copper nanocomposite based on poly-N-vinylimidazole was synthesized and characterized by a complex of modern physicochemical and biological methods. The low cytotoxicity of the copper nanocomposite in relation to the cultured hepatocyte cells was found. The possibility to involve the copper from the nanocomposite in the functioning of the copper-dependent enzyme systems was evaluated during the incubation of the hepatocyte culture with this nanocomposite introduced to the nutrient medium. The synthesized new water-soluble copper-containing nanocomposite is promising for biotechnological and biomedical research as a new non-toxic hydrophilic preparation that is allowed to regulate the work of key enzymes involved in energy metabolism and antioxidant protection as well as potentially serving as an additional source of copper