Applied Biochemistry and Microbiology最新文献

Polyextremophilic red microalgae of the genus Galdieria, which inhabit hot sulfur springs under conditions unusual for eukaryotes, are capable of heterotrophy. Among the dozens of exogenous organic substrates identified for Galdieria, ethanol is not mentioned as a possible energy source. It turned out that ethanol did not alter the growth of the model species Galdieria sulphuraria when grown in the dark. By contrast, the growth of microalgae is activated in the light, despite the known cell stressor effect of ethanol. The effect of ethanol as an oxidative stress factor has been indicated by the increase in cellular respiration observed in the dark and also in the light even before the activation of photosynthesis. The marked acceleration of growth of G. sulphuraria culture in the light is most likely due to the stimulation of respiration by ethanol with generation of CO₂ and its use by chloroplasts as an additional carbon substrate during the photosynthetic process. Compared to the classical organic substrate glucose, the light-induced growth of G. sulphuraria culture in the presence of ethanol is less intense. It can be speculated that ethanol stress in light induces a system of two consecutive key enzymes in the primary alcohol metabolism chain (alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase), which then leads to the eventual complete oxidation of ethanol, resulting in accelerated growth of G. sulphuraria.

Therapeutic effect of many plants is associated with the presence of various bioactive substances in them. The plant hormones—phytohormones—can be distinguished among these substances. When ingested into the human body, they affect physiological processes such as inflammation, glucose uptake, cell division, and resistance to diseases. It is hypothesized that phytohormones may be used as drugs with no side effects. One of them could be the phytohormone indolyl-3-acetic acid (IAA), which is a heteroauxin and can be synthesized by some microorganisms and animals, including mammals. This phytohormone is an important derivative of indole, which is catabolized from dietary tryptophan by the intestinal microbiota. IAA can scavenge free radicals, inhibit oxidative stress, and reduce the production of proinflammatory cytokines. As a ligand of the aryl hydrocarbon receptor, IAA can regulate intestinal homeostasis and suppress inflammatory responses. This review summarizes the current literature data on the vital role of IAA in the treatment of cancer, type 2 diabetes, rheumatoid arthritis, liver disease, Alzheimer’s disease, dental diseases, and microbial skin diseases. The purpose of this review is to draw attention and interest to IAA as a promising therapeutic drug.

The role of reactive oxygen species (ROS) and nitric oxide (NO) in the defense of Triticum aestivum L. (common wheat) against the rust fungus Puccinia graminis f. sp. tritici Erikss. and Henn. (Pgt) was studied using the example of the interaction between the resistant line of the cultivar Thatcher carrying the Sr25 gene from the tall wheatgrass Thinopyrum ponticum (TcSr25) and the susceptible cultivar Saratovskaya 29 (C29). The seedlings were treated with salicylic acid (SA) as an ROS inducer, verapamil as a Ca²⁺ channel inhibitor, sodium nitroprusside (NP) as a NO donor, and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (c-PTIO) as NO scavenger. Isolates with reaction 0 (immunity) and 1 (resistance with hypersensitive reaction, HR) were used to infect the seedlings. NO stimulated the growing tube orientation and the formation of the Pgt appressoria on the surface of resistant plants, as well as increased colony growth in susceptible plants if plants were treated one day before or simultaneously with infection. The generation of superoxide anion was the main cause of Pgt appressoria death on the stomata of resistant plants, while NO did not affect tissue penetration. ROS induced HR and accelerated the destruction of the cell cytoplasm, and NO contributed to the expansion of the necrosis zone in resistant plants.

Volatilomes of the basidial wood-destroying white rot fungus Trametes hirsuta LE-BIN 072 growing on a glucose–peptone medium (GP) with different types of wood sawdust (birch, alder, and pine) are represented by the following main groups of compounds: terpenes, aromatic compounds, fatty acid derivatives, and alkanes. The addition of sawdust to the cultivation medium led to a change in the spectrum of terpene and sesquiterpene compounds synthesized by fungus, as well as to a change in the ratio of the VOC component composition. On the control GP medium, β-elemene, β-barbatene, and γ-muurolene were detected; on the media with birch, alder, and pine sawdust, α-bulnesene, γ-cadinene, Δ3-carene, and camphene were detected. In silico analysis of the T. hirsuta 072 genome predicted ten genes encoding terpene synthases. Phylogenetic analysis showed that the proteins clustered with other basidiomycete terpene synthases into four major clades, suggesting that the enzymes in each cluster may produce related terpenes and sesquiterpenes.

Plasmid DNA (pDNA) is one of the possible types of vectors used in gene therapy. Escherichia coli is the most common bacterium for the production of pDNA. Lipopolysaccharides are the main component of the outer membrane of E. coli. Lipopolysaccharides are strong endotoxins, and their presence in pharmacological substances is highly undesirable. One of the approaches to eliminating endotoxin contamination of target substances is knocking out the genes of the lipopolysaccharide biosynthesis pathway. Using the CRISPR/Cas9 genome editing technology, we obtained a mutant form of the E. coli strain SCS110. We knocked out the genes kdsD, gutQ, lpxM, lpxL, lpxP, pagP, and eptA. As a result, lipopolysaccharide contamination of pDNA samples isolated by different methods from the mutant E. coli SCS 110 was significantly lower (19 to 295 times) than in pDNA samples from the original strain.

Bacterial infections still remain one of the main problems for healthcare, due to difficulties in timely diagnosis and increasing microbial resistance. Based on advanced nanotechnologies, in particular, nanozymes, as artificial enzymes with a wide spectrum of action, it is possible to create completely new tools for detecting infectious agents. Recent advances in the development of luminescent nanozymes capable of identifying pathogenic bacteria are discussed. The basic information about nanozymes with luminescent properties and their advantages over other variants of nanozymes are considered, and the key mechanisms for generating a luminescent signal that make it possible to detect bacterial cells are revealed. The main focus of the review is on the comprehensive characterization of luminescent sensor systems developed to date, which are aimed at visualizing bacteria, both in a free-living form and in biofilm formation. In addition, a description is given of nanozyme-based sensors that selectively detect biomarkers of bacterial infections using a luminescent signal. This review is focused on further progress in the development of luminescent nanozymes for the detection of bacterial pathogens, as well as on the search for innovative nanozyme technologies that expand the capabilities of clinical microbiology.

Beta-lactam antibiotic cephalexin is poorly recognized by bacterial beta-lactam binding proteins and therefore cannot be reliably detected by a group-specific receptor assay. For effective and rapid monitoring of cephalexin concentration in food products, the test systems based on high-affinity and selective binding of this antibiotic to polyclonal antibodies have been developed. The principle of the method for the test systems of enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay (LFIA) is based on the competitive interaction of (a) cephalexin, potentially contained in the samples, and (b) a cephalexin-protein conjugate immobilized in the wells of a microplate or on the membrane of a test strip, with (c) polyclonal antibodies against cephalexin conjugated with peroxidase or adsorbed on gold nanoparticles. The high specificity of the obtained polyclonal antibodies against cephalexin and the absence of cross-reactivity to a number of cephalosporins, penicillins, and antibiotics of other classes have been confirmed. In the ELISA system in a buffer solution and in a milk matrix, the detection limit, the IC₅₀ value, and the range of detected concentrations were 0.02, 1.0 and 0.025–100 ng/mL respectively. The limit of detection for visual and instrumental determination of cephalexin in the LFIA system were 1.5 and 0.1 ng/mL, and the working range of quantitatively measured concentrations was from 0.05 to 1.5 ng/mL. For both systems, the coefficient of variation of measurements was in the range of 2.5–8.0%. The test systems allow to detect cephalexin in milk without sample preparation. The recovery of cephalexin added to the milk samples was 90.0–106.7%. The presented developments can serve as the basis for kits of reagents for monitoring the content of cephalexin in food products.

All living systems are characterized by fundamental properties such as the ability to adaptation and self-regulation. Mammalian nonnuclear erythrocytes also have the ability to adapt to external effects, but their regulatory capabilities are limited by cytoplasmic mechanisms, including phase transitions of proteins and membranes. This is one of the most ancient mechanisms of adaptation of living systems to external and internal conditions. Erythrocytes under changes in plasma composition, aging, and energy depletion, undergo a reversible morpho-functional transformation, the transition from a discocyte to an echinocyte. The metabolic shifts occurring in this case correspond to a complex of universal changes that take place during erythrocyte transition to metabolic depression. As a rule, echinocytosis is considered as a pathological process preceding eryptosis and hemolysis. However, it can be also considered as the first stage of the implementation of a universal program of passive cell adaptation, the ultimate goal of which is to transfer the system to a state of suspended animation. The energy status of an erythrocyte is determined by the equilibrium of soluble and membrane-bound hemoglobin (Hb) forms. Compounds with pronounced electrophilic properties—nitric oxide and methylglyoxal—affecting this equilibrium can induce cell’s transition from one metabolic state to another. The mechanism of their action is largely related to the modification of thiol groups of membrane and cytoskeleton proteins, including reactive SH-groups of Hb. It seems relevant to consider their effect on the state of Hb and erythrocytes.

Adaptive Laboratory Evolution (ALE) is a novel approach to generating microbial strains with desired characteristics and producing value-added products. Additionally, ALE is employed as a means of enhancing comprehension of the genetic and/or metabolic pathways of evolution. The objective of this review is to analyze the results of studies that elucidate and demonstrate the potential of microorganisms as model objects for laboratory evolutionary experiments. These experiments are becoming increasingly prevalent in the study of adaptation, the evaluation of evolutionary dynamics, and the testing of various evolutionary hypotheses. Concurrently, ALE has demonstrated itself to be a promising and efficacious methodology, which, when employed for biotechnological applications, has already resulted in the generation of novel and useful microbial strains. It is important to note that the current achievements not only demonstrate the power and versatility of this approach but also highlight a number of unanswered questions. The conclusions drawn on the basis of ALE require a cautious interpretation of the results obtained.