Nanotechnologies in Russia最新文献

The culturing conditions for the production of cells of the purple nonsulfur bacteria Rba. capsulatus, which possess a minimal capsule, are selected and the effectiveness of their use in induced transformation by electroporation to transfer exogenous DNA in comparison with cells cultivated on other types of conventionally used media is shown. It is found that, upon the electroporation of plasmid DNA (pDNA) into the cells of Rba. capsulatus according to the selected procedure, the survival rate of the culture is an unstable quantity, which requires optimization of the conditions for obtaining electrocompetent cells and careful selection of the electric-shock treatment mode. For the first time, the fundamental possibility of using an approach for protection against the destruction of pDNA by the restriction modification system (RMS) of Rba. capsulatus by means of in vitro methylation with a cell-free extract of this culture, as well as transformation of the treated pDNA into competent cells of this bacterium by electroporation is demonstrated.

The results of the microbial synthesis of extracellular silver nanoparticles (Ag NPs) in a liquid medium using the metal-reducing Shewanella oneidensis MR-1 strain and silver-nitrate salts are presented. The shape of the Ag NPs is determined by scanning transmission electron microscopy as close to spherical; more than 50% of Ag NPs have dimensions from 10 to 15 nm. The spectra of energy-dispersive X-ray microanalysis show the presence of Ag peaks in all samples of biogenic Ag NPs. The interplanar distances in the crystals of Ag NPs are 2.71 Å. Fourier-transform infrared (IR) spectroscopy confirms the presence of nitrogen-containing organic compounds of protein nature on the surface of the nanomaterial. The values of the hydrodynamic diameter, zeta-potential, and optical parameters of Ag NPs are determined by dynamic light scattering and spectrofluorimetry. It is shown that a large amount of Ag NPs is present on the surface of S. oneidensis MR-1 cells during biosynthesis. A technological approach is proposed to increase the yield of nanomaterial using the ultrasound treatment of cells, followed by the isolation of Ag NPs. It is shown that the compositions of the protein corona in Ag NPs obtained by the standard method and isolated from the cell surface after ultrasound treatment, as well as the size of Ag NPs, have some differences. A technological method for producing powdered preparations of nanomaterial by lyophilization (freeze drying) of aqueous suspensions of Ag NPs and cellular biomass containing Ag NPs is developed. The possibility of restoring preparations in the form of aqueous suspensions without the agglomeration and sedimentation of nanoparticles is shown. A high biocidal activity of all forms of the nanomaterial as antimicrobial agents of a wide spectrum of activity against gram-positive and gram-negative bacteria and microscopic fungi, including yeasts and phytopathogenic mold fungi, is established, which can be used to create polymer nanocomposites of varying nature with antibacterial properties.

A primary study of the quality of wastewater treatment and the composition of the microbial community of the activated sludge of the treatment plant and the storage pond of a pig farm is carried out. Activated sludge is widely represented by nitrogen-cycle microorganisms, including denitrifying and nitrifying bacteria (Nitrosomonas (4%), Nitrospira (8%), as well as, to a lesser extent, anammox microorganisms (Candidatus Kuenenia (0.2%)). Phosphorus is removed by phosphate-accumulating bacteria, primarily Thauera (5%) and Candidatus Accumulibacter (1%). Two-stage aerobic treatment has a very high degree of chemical oxygen demand (97%) and ammonium (99.7%) removal. At the same time, a rather high concentration of nitrates (569 mg/L) and phosphates (75 mg/L) in the treated water probably caused the dramatic development of purple sulfur bacteria of the genus Thiolamprovum in the storage pond, coloring the water a red-burgundy color (“borscht” color). To improve the quality of treatment, reduce energy costs, obtain an energy carrier in the form of biogas, as well as solve the problem of water bloom in the storage pond, a scheme for anaerobic-anoxic-aerobic wastewater treatment of the pig farm is proposed.

A field trial to study the effect of preplant and foliar treatment of potatoes (lat. Solanum tuberosum) of Red Scarlett variety with dispersions of silver nanoparticles stabilized with polyhexamethylene biguanide hydrochloride was conducted. Silver nanoparticles were obtained by chemical reduction and characterized by UV–Vis spectrophotometry, transmission electron microscopy, and dynamic light scattering. The obtained nanoparticles were roughly spherical shape with the average diameter of 4.92 ± 2.66 nm. Preplant treatment of potato tubers and foliar treatment of potato plants were conducted with dispersions of silver nanoparticles with the concentrations of 5 and 0.2 mg/L, respectively. The treatment of potato with the dispersions resulted in an increase in values ​​of morphological indicators such as stem height, tops weight and leaf weight which in turn caused a significant increase in the yield (from 10.6 to 21.9% compared to the control variant) and commercial quality of the tubers. Notably, the maximum increase in the yield was obtained with the largest number of the treatments. In addition, silver dispersions showed a phytoprotective effect on potato plants which manifested in a decrease in damage to leaves by Phytophthora infestans from 30 to 7–8%. An explanation for the observed phytoprotective effect of silver nanoparticles based on the analysis of enzymatic activity in plant leaf tissues was proposed. The obtained results demonstrate high potential of application of drugs based on silver nanoparticles in horticulture as means of stimulating of growth and protection of plants.

Infectious diseases of small domestic ruminants caused by viruses belonging to the Capripoxvirus genus are a serious economic threat. However, the diagnostic tools currently available for these pathogens do not provide sufficient strain information for effective disease control. This can be solved by sequencing and analysis of the full virus genome, which is currently achievable by the use of next generation sequencing technologies followed by metagenomic analysis. This review discusses the biology of Capripoxvirus pathogens, and the diagnostic and disease control tools in the context of introducing metagenomic analysis as the primary tool for pathogen identification.

The formation and maturation of stone fruits are complex processes that require the involvement of many genes and gene products. Early research on the peach fruit (Prunus persica (L.) Batsch) and the differences in ripening periods of its cultivars mainly focused on the already ripe fruit. However, in the early stages of fruit formation, there may be significant differences between cultivars that have different ripening periods. We identify and analyze differentially expressed genes (DEGs) between flowers, fertilized ovaries, and fruits at the S1 stage in cultivars that have different ripening periods, both between cultivars and from stage to stage. Gene expression in peach cultivars that have different ripening periods differs even in the early stages of fruit formation. The most significantly enriched categories of DEGs in this case are photosynthesis, redox reactions, and processes associated with cell-wall modification; thus, by the time the fruit forms, hormonal reception becomes more important.

An approach is proposed for solving two urgent problems: the environmentally safe conversion of metal-containing sludges and the creation of efficient and low-cost agricultural fertilizers from them. The highly dispersed state of the sludge makes it bioactive and its use in the form of a dispersed metallurgical sludge (S)‒natural component humic acids (HA) complex makes it biocompatible with plants and more environmentally safe. The optimum HAs : S concentration ratios (1 : 5) in the complex are determined when using it as a plant growth and development stimulator. A set of analytical methods, including optical and scanning electron microscopy, energy-dispersive X-ray microanalysis, X-ray diffraction, and infrared (IR) spectroscopy, is applied. An increase in the activity of catalase and peroxidase enzymes and, as a result, in wheat growth rates facilitates an increase in the yield by 20% when the complex is used.