Comparative evaluation of the influence of no-till and traditional treatment on the biological activity of agricultural chernozem of the Stavropol region

Using the method of inoculation on elective nutrient media, the abundance and activity of taxonomic (bacteria, actinomycetes, micromycetes) and functional (nitrogen fixers, ammonifiers, denitrifiers of amylolytic, cellulolytic) groups of microorganisms in agrochernozems of the Stavropol region under the influence of various tillage systems – direct seeding (no-till) and moldboard plowing with the turnover of soil horizon (traditional treatment). Analyzes were carried out for such crops as winter wheat, corn, sunflower and soybean with/without application of mineral fertilizers. Traditional tillage for the majority of crops leads to increased activity of aerobic ammonifiers, cellulolytics, denitrifiers, actinomycetes and micromycetes. No-till technology, in its turn, increases the intensity of anaerobic cellulolytics and nitrogen fixers, aerobic diazotrophs and amylolytics activity. The most responsive crop, under which the biological activity of almost all groups of microorganisms increased in the no-till variant, was corn, while winter wheat contributed to the increase in the number of microorganisms in the moldboard plowing variant. The use of mineral fertilizers provoked the growth of soil biological activity under sunflower sown directly in the soil, while conventional tillage resulted in higher soil biological activity without application of mineral fertilizers

Optimization of fixation methods for observation of bacterial cell morphology and surface ultrastructures by atomic force microscopy

Fixation ability of five common fixation solutions, including 2.5% glutaraldehyde, 10% formalin, 4% paraformaldehyde, methanol/acetone (1:1), and ethanol/acetic acid (3:1) were evaluated by using atomic force microscopy in the present study. Three model bacteria, i.e., Escherichia coli, Pseudomonas putida, and Bacillus subtilis were applied to observe the above fixation methods for the morphology preservation of bacterial cells and surface ultrastructures. All the fixation methods could effectively preserve cell morphology. However, for preserving bacterial surface ultrastructures, the methods applying aldehyde fixations performed much better than those using alcohols, since the alcohols could detach the surface filaments (i.e., flagella and pili) significantly. Based on the quantitative and qualitative assessments, the 2.5% glutaraldehyde was proposed as a promising fixation solution both for observing morphology of both bacterial cell and surface ultrastructures, while the methonal/acetone mixture was the worst fixation solution which may obtain unreliable results

Low-Dose Ionizing Radiation Affects Mesenchymal Stem Cells via Extracellular Oxidized Cell-Free DNA: A Possible Mediator of Bystander Effect and Adaptive Response

We have hypothesized that the adaptive response to low doses of ionizing radiation (IR) is mediated by oxidized cell-free DNA (cfDNA) fragments. Here, we summarize our experimental evidence for this model. Studies involving measurements of ROS, expression of the NOX (superoxide radical production), induction of apoptosis and DNA double-strand breaks, antiapoptotic gene expression and cell cycle inhibition confirm this hypothesis. We have demonstrated that treatment of mesenchymal stem cells (MSCs) with low doses of IR (10 cGy) leads to cell death of part of cell population and release of oxidized cfDNA. cfDNA has the ability to penetrate into the cytoplasm of other cells. Oxidized cfDNA, like low doses of IR, induces oxidative stress, ROS production, ROS-induced oxidative modifications of nuclear DNA, DNA breaks, arrest of the cell cycle, activation of DNA reparation and antioxidant response, and inhibition of apoptosis. The MSCs pretreated with low dose of irradiation or oxidized cfDNA were equally effective in induction of adaptive response to challenge further dose of radiation. Our studies suggest that oxidized cfDNA is a signaling molecule in the stress signaling that mediates radiation-induced bystander effects and that it is an important component of the development of radioadaptive responses to low doses of IR

Laser beam synthesis of cooper phthalocyanine based films with low dimensional structuring

Thin films of copper phthalocyanine (CuPc) and CuPc - polystyrene (PS) composites were prepared by laser evaporation in vacuum. The crystalline structure and morphology of films were investigated by ТЕМ, AFM and optical absorption methods in relation with dc dark electrical conduction, photoconduction and adsoфtion-гesistive response to NO2