Applied Biochemistry and Microbiology最新文献

Inorganic polyphosphates (polyPs) are universal regulatory compounds and participate in the control of gene expression, stress adaptation, membrane transport, and cell motility. They play an important role in bone tissue development, thrombosis and inflammation processes, signal transmission in nerve cells, and amyloid formation. These polymers participate in phosphorus homeostasis in both living cells and natural and technogenic ecosystems. PolyPs are used as fertilizers, food additives, and water treatment compounds and flame retardants. Modern, highly sensitive, and specific methods for polyP analysis are necessary for solving fundamental problems for regulation of biochemical processes and for a number of practical tasks, such as monitoring the state of environmental objects, food quality, and developing new methods for treating bone diseases, the cardiovascular system, and neurodegenerative pathologies. Currently, efficient and highly specific methods for polyP assay have been developed, such as special extraction methods, enzymatic analysis, electrophoresis, DAPI staining, and microscopic methods, including micro-X-ray analysis. NMR retains its importance, especially for determining the polymer chain length. In this review, we consider polyP analysis methods from the point of view of problems solved in the study of various biological objects, with special attention to the most modern and widespread approaches.

This study concerns the antimicrobial effects of various natural polyphenols, namely resveratrol, dihydroquercetin, dihydromyricetin, baykalein, chrysin, rutin, and daidzein, using a model test culture of Bacillus subtilis VKPM B-4419 isolated from children’s dairy products. Pretesting of polyphenols on pathogenic microorganisms, including the species Staphylococcus aureus and Escherichia coli, and fungi of Candida albicans and Aspergillus niger, showed that four of the eight compounds tested, namely daidzein, resveratrol, dihydroquercetin, and dihydroquercetin, inhibited the growth of Gram-positive S. aureus and Gram-negative E. coli. Daidzein and resveratrol at a concentration of 15 mM proved most successful against bacterial pathogens, while dihydroquercetin blocked the growth of S. aureus at a concentration of 30 mM and dihydromyricetin inhibited the growth of E. coli at 150 mM. None of the polyphenols studied inhibited the growth of the fungal pathogens. Study of the impact of natural polyphenols on the growth and viability of the model nonpathogenic Gram-positive strain of B. subtilis VKPM B-4419 confirmed that daidzein and resveratrol inhibited its growth by 45–56% compared to that in the control. It was comparable to the action of the antibiotics vancomycin and chloramphenicol. Daidzein and resveratrol formed growth-free zones upon testing with the method of diffusion into agar. Daidzein inhibited bacterial metabolism at the stationary growth stage by 26%, while the combined effect of daidzein and chloramphenicol showed an additive action up to 76%, nearly equal to the impact of the compounds separately. We conclude that the application of the bacterial test model of nonpathogenic B. subtilis VKPM B-4419 is likely to be promising for the design and prescreening of medicine, including tests for synergism and additivity of the combined action of phytochemical compounds and antibiotics.

Immobilization of lactic acid bacteria (using Enterococcus faecium as an example) in silanol-humate gels (SHG) not only increases the number of viable cells during long-term storage compared to the control (as previously shown), but also enhances their potential probiotic properties. The antagonistic activity against test strains of microorganisms (E. coli, S. aureus, and Y. lipolytica) increases up to 0.7–5 times compared to planktonic cultures. The number of E. faecium in SHG under conditions of acid and enzymatic stress, simulating the conditions of the upper parts of the human gastrointestinal tract, is maintained at a level of 30–80% of the initial level, while in the control (unstabilized preparation), almost complete cell death is observed. The technological indicators of fermented milk products obtained using E. faecium immobilized in SHG as starters are improved: the time of clot formation is reduced from 48 to 44 hours and the organoleptic assessment is improved. The safety of SHG for animals has been demonstrated when ingested at doses not exceeding 5 g/kg/day. SHG can be recommended for use in veterinary medicine and the food industry as a feed additive–adsorbent and stabilizer of probiotic cultures as components of food products.

The currently available information on the properties of proteins of the transferrin family—multifunctional cationic proteins involved in various enzymatic, immune, and regulatory processes in the bodies of mammals and humans—is reviewed. The literature on the physiological role, structure, mechanism of metal ion binding, antibacterial properties, and the prospects for the practical use of transferrins and oligopeptide derivatives is summarized.

A comparative assay of 2D gels of extracts from the Yarrowia lipolytica Po1f strain and its transformant of Y. lipolytica Po1f pUV3-Op with integrated intracellular histidine acid phytase from the Obesumbacterium proteus enterobacteria was performed. Upon the identification of protein profiles with MALDI-TOF mass spectrometry to determine differentially expressed proteins, seventeen protein zones were identified with some change in expression. Among the proteins with the decreased expression in the transformant of Y. lipolytica Po1f pUV3-Op, there were noted Peptidase M20, Carboxypeptidase, Proteasome assembly proteins Proteasome chaperone 2, and YALI0C01221p. The proteins with increased expression in the Po1f transformant pUV3-Op contained Nucleoside diphosphate kinase, proteins with chaperone properties of YALI0B15840p, glycerol kinase acetylated at the N-terminal edge of the molecule. Using the analysis of the proteomic profiles of two strains of the Y. lipolytica yeast we concluded that the protein composition of the transformant of Y. lipolytica Polf pUV3-Op carrying the phytase gene microencapsulated in a yeast cell possesses some metabolic features that let it, on the one hand, successfully synthesize and accumulate a heterologous functional target enzyme in the cells, and, on the other one, induce the response to endogenous stress caused by active synthesis and folding of a heterologous protein due to moderate suppression of proteasome degradation and promotion of chaperone protection.

The escalating threat of multidrug-resistant (MDR) pathogens necessitates urgent exploration of natural antimicrobial alternatives. This study identified a novel surfactin-producing Bacillus subtilis strain ZCK-1 isolated from environmental soil. Whole-genome sequencing revealed a 4 043 370 bp (GC content: 43.73%) encoding 4041 protein-coding genes, including biosynthetic gene clusters for lipopeptides. A surfactin extract was obtained through XAD 16N macroporous resin adsorption coupled with ethanol elution and vacuum rotary evaporation. The surfactin demonstrated potent antibacterial activity against clinically critical Gram-positive pathogens, notably Streptococcus pneumoniae, Corynebacterium striatum, and drug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). Mechanistic studies revealed dual modes of action: disrupting bacterial membrane integrity and degrading genomic DNA. The compound exhibited remarkable thermal stability (100°C, 30 min) and tolerance to extreme pH (2.0–13.0), proteases (trypsin/pepsin), while remaining susceptible to lipase-mediated degradation. Acute oral toxicity assays in murine models confirmed biosafety (LD₅₀ > 5000 mg/kg). These findings position surfactin from B. subtilis ZCK-1 as a promising candidate for combating MDR infections in clinical and industrial settings.

In this paper, we describe mechanochemical approach as an environmentally friendly method for the functionalization of chitosan with gallic acid. Coupling with a polysaccharide is one way to stabilize antioxidants and improve their bioavailability. Since gallic acid is a solid compound with limited solubility and a high melting point (220–240°C), it was of interest to conduct its interaction with chitosan using solid-state synthesis technique under shear deformations. The experimental conditions were selected using a pilot twin-screw extruder designed for processing solid dispersions. DSC and WAXD data were used for study of response of the system to shear deformation. The insertion of gallate groups onto the polymeric backbones was confirmed by ¹H NMR, FTIR and UV–vis analyses. It was found that gallate groups are predominantly linked to chitosan via salt bonds. Depending on the synthesis conditions, the amount of bound gallic acid was more than 600 mg per 1 g of chitosan. In contrast to the physical mixing of components, the resulting products swelled well and partially dissolved in water, and tended to form aggregates with an average size of 206 ± 36 µm in aqueous media. It was shown that the obtained compositions have moderate antibacterial activity against Gram-positive bacteria (Bacillus subtilis). The proposed approach is promising for the creation of biologically active solid compositions capable of being processed into final products due to ultradispersion and gelation in water with the possibility of use in the form of hydrogels, sprays, and sponge materials.

Secondary metabolites, some of which have antimicrobial activity, are a key tool that helps filamentous fungi to occupy a wide variety of ecological niches. In particular, some of these microorganisms are capable of growing on painting materials, which leads to their deterioration. However, this natural reservoir has not been screened for antimicrobial compounds. In the current work, we studied the activity of fungi-destructors of tempera painting isolated in the State Tretyakov Gallery from: the Orthodox icon “Prophet Solomon” of the 18th century—Penicillium chrysogenum STG-117; the Old Russian icon of Sergiev Posadsky school dating to the 15th century—Penicillium rubens STG-305, Penicillium sp. STG-333, P. chrysogenum STG-344, Aspergillus fumigatus STG-345, Penicillium sp. STG-348; and from the Old Believer icon “Descent into Hell” of the 16th century—Syncephalastrum sp. STG-160, Cladosporium sphaerospermum STG-161. The strain Simplicillium lamellicola STG-96 was isolated in Hall 61 of the State Tretyakov Gallery. Optimization of cultivation conditions was carried out for the three strains, STG-96, STG-117 and STG-344, that demonstrated promising antimicrobial activity against panel of representative test cultures on two nutrient media—Czapek-Dox and #2 Gause, with different pH values, in the range of 5.0–10.0. The highest antimicrobial activity was observed at the second and third week of culturing. The antimicrobial activity was also tested for novel isolates: STG-160, STG-161, STG-305, STG-333, STG-345 and STG-348. Strains from the Aspergillaceae family showed high activity against such representative test cultures as methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Mycobacterium smegmatis. Our work demonstrates that fungi-destructors of tempera painting are promising producers of antimicrobial compounds.

Oxidative stress can produce high levels of reactive oxygen species following exposure of cells to endogenous and exogenous factors. Recent experiments show that oxidative stress plays an important role in the cytotoxicity of many materials. The aim of this study was to measure the antiproliferative effect of hawthorn Crataegus pinntifida doped with chitosan hydrogels on cultured HCT-116 colon cancer cells and intracellular malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) activities. Cell proliferation on hydrogels was examined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay. Cell viability results showed that hydrogels showed significant cytotoxicity activity in HCT116 cells compared to cisplatin. Furthermore, MDA, SOD and CAT activities in HCT-116 colon cancer cells cultured on all hydrogels showed significant differences compared to the control group and each other. The hydrogels showed a significant decrease in MDA levels in HCT116 cells and considerable increase of CAT and SOD activities. According to our findings, we suggest that hawthorn extract hydrogels doped into chitosan may have anticancer activity.

The plant Calendula officinalis L. (marigold, belonging to the Asteraceae family) underwent foliar salicylic acid (SA) elicitation in both greenhouse and open-field experiments. Spectrophotometric analysis revealed variations in flavonoid levels in C. officinalis flowers from seven varieties cultivated in the greenhouse after applying four different concentrations of the elicitor (0.1–2 mM), with the highest flavonoid content observed at 1 mM SA. High-performance liquid chromatography with photodiode array and ion trap time-of-flight mass spectrometry (HPLC–PDA–IT–TOF–MS) analysis of the Golden Sea variety indicated significant changes in its phenolic profile, which contained 19 compounds in its original state and 35 compounds after 1–2 mM SA treatment. A total of 30 flavonols, primarily isorhamnetins, belonging to the quercetin and isorhamnetin series, were identified as acylated and non-acylated O-glycosides. Chromatographic separation of the SA-treated C. officinalis extract led to the isolation of a new flavonoid, identified using ultraviolet (UV) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry (MS) as isorhamnetin 3-O-(4′′-O-acetyl-6′′-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside (calendoside V). The application of 1 mM SA resulted in the 2.2-fold increase in flavonoid content in C. officinalis flowers compared to the control. This increase was primarily attributed to a greater accumulation of isorhamnetin glycosides, which increased by 129.3% compared to the control, while quercetin derivatives exhibited a more modest increase of 10.9%. A similar trend was observed in an open-field experiment, where increased flower productivity and flavonoid levels were noted, particularly in relation to isorhamnetin accumulation. The elicitation of C. officinalis with SA is a straightforward and cost-effective method for improving the quality of this medicinal plant and for producing raw materials with the desired composition.