The formulation of microbial biomass represents a critical step in advancing the commercial development of prospective biological control products. Trichoderma asperellum has demonstrated biological control capability against Fusarium head blight. In the present studies, Trichoderma asperellum was grown in liquid media of differing composition. The effect of various amendments on the preservation of the viability and competitiveness, in vitro, of fungal mycelium and spores in a liquid paste was determined. The amendments with greatest effect were the addition of starch as a food base, reduction of metabolic activity by lowering the pH of the biomass paste and the addition of small amounts of copper. Oxygen availability was also shown to be important in maintaining biomass viability and competitiveness. Optimization of these factors produces a biomass paste formulation of T. asperellum that remains active, in vitro, for at least 6 months at room temperature.
We study a phenomenon of stationary pattern formation in colonies of imperfect mycelial fungi. Conditions required in order for patterns to appear and general features of spatial structures are investigated. A mathematical model is proposed for the description of this macroscopic self-organizing system. The model is demonstrated to be consistent with experimental data. Computer simulation results show that the ability of fungi to produce inhibitors is necessary for zone formation. According to the model a certain ratio of substrate and metabolite concentrations and also of corresponding diffusion coefficients has a significant influence on general parameters of spatial distribution of fungi.
Oxygen-active disinfectants are widely used for nonspecific prevention of infectious diseases: hydrogen peroxide, chlorine dioxide, potassium fluoride peroxohydrate, perborates, persulfates, perphosphates, percarbonates. These compounds have a broad spectrum of antimicrobial activity against bacteria (including Mycobacterium tuberculosis), viruses, fungi and spores of bacilli. The primary "target" of exposure to oxygen-containing disinfectants in bacterial cells are proteins and lipids of cytoplasmic membranes, and in bacterial spores - proteins and lipids of spore membranes. When exposed to hydrogen peroxide on a bacterial cell at the stage of contact with the cytoplasmic membrane, hydrogen peroxide decomposes into highly reactive hydroxyl radicals, which have a destructive effect on the membranes. Hydroxyl radicals are powerful oxidizing agents, have a short period of existence, interact with lipids, proteins, nucleic acids. Oxidation of lipids, especially unsaturated fatty acids, leads to an increase in membrane permeability. During the oxidation of membrane proteins consisting of amino acids with disulfide bonds, the latter are converted into SH-radical, as a result of which cross-links are formed at amino groups, protein-lipid complexes are formed; proteins are oxidized and denatured, which leads to cell death. Not only hydroxyl radicals have a damaging effect, but also other intermediate products of the decomposition of hydrogen peroxide: hydronium cation - H3O +; perhydroxylanion - HO2-.
This is a personal testimony of the experience of a teacher of literature, who was facing a class of frightened students on February 24, 2022. The young people wanted an explanation for what was happening. The teacher did not have one and is trying to come to terms with the Russian invasion of her country by reviewing some aspects of Russia culture which have been a guiding light to her in her career as a literature teacher. Obstructing any form of dissemination of Russian culture amongst student in Ukraine is the knowledge that the Russian Federation’s aim is the total negation of Ukrainian culture and nationhood.
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