Applied Biochemistry and Microbiology最新文献

The method of subcritical and supercritical ethanolysis was used to determine its impact on the degree of fermentolysis of wheat straw polysaccharides and the yield of sugars. The heat treatment of raw materials in ethanol was performed in the temperature range of 130–355°C (30 MPa, 10 min). The intensity of biomass delignification and hydrolysis of straw polysaccharides during processing is determined by the temperature. Chemical processes occurring in the wheat straw biomass under subcritical ethanolysis conditions can contribute to the enzymatic hydrolysis of polysaccharides of technical cellulose and are associated with the destruction of easily hydrolyzable pentosans and lignin. Upon the transition to the supercritical region, the intensity of hydrolysis of straw polysaccharides increases, resulting in an increase in the yield of the fraction of water-soluble compounds at 355°C to 14.5% dry mass and a decrease in the yield of insoluble straw residue (technical cellulose) to 26%. Under these conditions, cellulose is the main source of soluble carbohydrates. The low yield of technical cellulose obtained at ethanolysis temperatures above 285°C and the high content of lignin in it make it unsuitable for the enzymatic production of sugars. In the temperature range of 200–250°C, the yield of technical cellulose was 77–87% dry mass and the yield of sugars during its enzymatic hydrolysis was 27–33% dry mass. The results substantiate the possibility of using subcritical ethanolysis as an activation method for the enzymatic hydrolysis of straw cellulose.

A biotechnological method based on the use of aqueous dispersions, or colloidal solutions, of fullerene-containing compounds for the treatment of seed material, which provides growth stimulation and contributes to an increase in plant yield, has been proposed. It was found that aqueous dispersions of fullerene C₆₀ and salts of amino acid derivatives of fullerene C₆₀ possess pronounced antioxidant activity and a wide range of other properties of biological activity. The growth-stimulating effect of aqueous dispersions of fulle-rene C₆₀ and salts of amino acid derivatives of fullerene C₆₀ on plants was shown to be effective in the case of their application for pre-sowing treatment (soaking) of seeds. In field experiments on the example of spring wheat of the “Lada” variety, the increase in plant yield, weight, and number of grains in the ear, which was promoted by pre-sowing treatment of seeds in the presence of fullerene-containing aqueous dispersions, was demonstrated. The proposed biotechnological approach has prospects for effective application in agriculture for seed treatment and increasing yields of important food crops.

The isolation and identification to species of 85 strains of osmotolerant yeasts related to Ascomycota from bees and bee-associated substrates, such as honeycombs, bee bread, and honey flowers collected in the republics of the Caucasus region including Dagestan, Kabardino-Balkaria, North Ossetia, and the Chechen Republic, as well as from candied fruits and fruit leather, are reported. Due to elective selection conditions and specific substrates, the isolated yeasts did not show much species diversity. Representatives of the genera Zygosaccharomyces and Starmerella prevailed among the isolated osmotolerant yeasts. When the levels of glycerol accumulation by the representatives of the identified genera were studied, the highest glycerol production in the absence of sulfites inhibiting the fermentation process was recorded in the Y-5206 and Y-5190 strains belonging to the species Pichia kudriavzevii, namely, 5.9 and 7.8 g/L, respectively. Under the sulfite stress conditions, when the medium pH was 8.0, the highest glycerol production level of 23.5 g/L was recorded in the S. cerevisiae Y-5189 yeast. The highest rate of glucose-to-glycerol conversion (46.3%) was shown by the Zygosaccharomyces roxii yeast strain Y-5182 in the presence of sulfites. The strains of osmotolerant yeasts belonging to the species Zygosaccharomyces roxii, as well as to all species in the genus Starmerella, which are characterized by the highest glucose-to-glycerol conversion levels at a low level of ethanol production and are able to accumulate extracellular glycerol efficiently in the absence of sulfite stress, may be of potential interest for further studies aimed at developing biotechnologies for production of this alcohol.

The results of application of an original antimicrobial polymer hydrogel based on polyvinylpyrrolidone as a local depot of antibacterial drugs for the prevention of chronicization of the infectious process during hip joint prosthetics in implant-associated infection in rabbits are presented. At the first stage, intramedullary osteomyelitis of the femur of the animals was modeled by implantation of the infected limb. On the 14th day, a second surgical intervention with sanitation of the focus of infection, removal of the limb, and unipolar hip arthroplasty was performed. All rabbits were divided into two groups: experimental, with application of the experimental gel at the stage of endoprosthesis (n = 3), and control, without gel (n = 3). After withdrawal from the experiment on the 90th day, a morphological study with evaluation of changes in the soft tissues and medullary canal, as well as microbiological analysis of samples of soft tissues, bone structures, and the removed endoprosthesis stem were carried out. In the control group, Staphylococcus aureus contamination was detected in two out of three animals, while in the experimental group, such bacteria were not detected in any of the samples tested. A comparative analysis of the cellular infiltrate in soft tissues revealed that the amount of multinucleated giant cells was significantly higher in the experimental group, and the amount of neutrophylic granulocytes, as indicators of the activity of the infectious process, were significantly higher in the control group. Thus, the use of the experimental antimicrobial polymeric hydrogel allowed us to prevent the development of a chronic infectious process, despite the fact that endoprosthesis was performed during sanitation of the osteomyelitis focus and a short course of antibacterial therapy. The presence of a pronounced giant cell reaction in soft tissues requires further investigation and at a later time after surgical intervention.

One of the most frequent causes of endocrine system pathologies is hormonal imbalance. Special enzymes, 17β-hydroxysteroid dehydrogenases, are involved in the regulation of the biological activity of androgens and estrogens in the body. To date, 15 types of these enzymes have been discovered. They play an important role in the biosynthesis or inactivation of various steroid hormones. Studying the structure of these enzymes allows the development of highly specific inhibitors as potential therapeutic agents for the control of hormone-dependent diseases and suggests the ways to modify similar enzymes for biotechnological hormone production. This paper presents an optimized protocol for the isolation and purification of 17β-hydroxysteroid dehydrogenase type 5 from Mus musculus, as well as analysis of the structure of this enzyme by the methods of dynamic light scattering and small-angle X-ray scattering.

The use of synthetic methane-consuming communities is a promising direction for increasing the efficacy of cultivation of methanotrophic bacteria. Non-methanotrophic satellites as a part of bacterial associations are able to utilize metabolites and lysis products that inhibit growth of a dominant bacterial culture. This research allowed us to determine the positive effect of Brevibacillus brevis on biomass accumulation during co-cultivation with the methanotrophic bacteria of the genera Methylosinus and Methylocystis. It was also revealed that the stationary phase occurs later for methane-consuming bacteria in association with Brevibacillus brevis, Cupriavidus necator, and Azospirillum lipoferum. During cultivation of binary associates, including Azospirillum lipoferum and Brevibacillus brevis, an increased growth rate was observed for selected methanotrophic bacteria in the presence of the inhibitory methanol concentration. An increase in the proportion of protein was found in the biomass of binary associates with Cupriavidus necator as a satellite. It was shown that the actinobacteria Nocardia farcinica has a negative impact on the growth rate of synthetic methane-consuming communities. Cultivation of methanotrophs with selected non-methanotrophic bacteria in synthetic microbial communities allows us to intensify the growth of the desired bacterial culture and potentially enhance cultivation productivity.

L-threonine is an essential amino acid that is used in the agricultural, pharmaceutical, and food industries. In the present study, L-threonine production was significantly increased in a producer strain of Escherichia coli when grown on various carbon sources through an integrated approach to alter the metabolism of the strain. First, increasing the ability of E. coli to assimilate acetate through adaptive laboratory evolution has reduced its negative impact on the fermentation process and threonine production. Secondly, strengthening the deacetylation process at the later stages of the fermentation process made it possible to achieve a significant increase in the productivity of the strains.

Three-dimensional bioprinting (3D bioprinting) is a new emerging field that is currently having a significant impact on medicine and biology. This technology has attracted the attention of many researchers from various academic disciplines. In biology and medicine, bioprinting is currently used mainly to create functional tissue structures. This technology makes it possible to produce structures quickly in automatic mode with high accuracy. This review provides information on the use of 3D bioprinting in medicine and biology and describes examples of the creation of various tissue structures using this technology.

Escherichia coli strains are widely used in biotechnology for the production of compounds of great interest, such as L-amino acids and recombinant proteins. The aim of this study was to determine the effect of protein Nε-lysine acetylation processes on the metabolism of commonly used E. coli strains MG1655 and BL21(DE3), as well as strains producing the amino acids L-threonine and L-proline. We demonstrate that the acetylation profile of one of the key enzymes of glycolysis, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), depends on the strain in which this protein was synthesized. Deletion of genes involved in acetate metabolism and acetylation of the ε-amino group of protein lysine affects the metabolism of the producer strains and the productivity of the target amino acids. Approaches involving modulation of protein acetylation may be useful in metabolic engineering in creating more efficient producer strains.

The creation of potato cultivars with resistance to virus Y (PVY) will allow one to solve successfully the problems of yield losses of this important vegetable and industrial agricultural crop. For replication and systemic spread, PVY recruits the translational apparatus of potato cells by interacting with host eIF4E translation initiation factors. By reducing the expression of genes encoding plant eIF4E, it is possible to limit both potyvirus replication in the host cell and further spread. Here, the production of potato cv. La Strada plants with inhibition of SteIF4E1 and SteIF4E2 gene expression through the use of RNA-interference technology is described. As a result of transformation with the marker-free expression cassette consisting of potato gene fragments (promoter and terminator of the StLhca3 gene and two inverted repeats of the SteIF4E1 gene separated by the Strbcs1 intron), transgenic lines with a high degree of suppression of target genes were obtained. Downregulation of SteIF4E1 and SteIF4E2 expression resulted in stunted growth and reduced overall productivity of potato plants and, at the same time, stable resistance to PVY infection. The use of a marker-free strategy in genetic transformation ensured the production of virus-resistant potato lines without inserting foreign reporter genes into their genome, which is extremely important from the point of view of environmental safety and public acceptance of genetically modified agricultural crops.