Applied Biochemistry and Microbiology最新文献

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.

Sugarcane molasses is a byproduct of the sugar industry. Its low cost and high remnant sugar content make it an ideal carbon source for bioethanol fermentation using the yeast Saccharomyces cerevisiae as a brewer. After long-term domestication, industrial S. cerevisiae became strongly adaptable to sugarcane molasses. To understand the related underlying mechanisms, we sequenced and analyzed the whole genome of the sugarcane-isolated diploid industrial S. cerevisiae A1015 strain. Compared to the S288c strain and two other wild isolates collected from the same environment, we observed that the A1015 strain possesses several specific genomic characteristics such as high heterozygous nucleotide variations (including single nucleotide polymorphisms and insertion/deletions). This result indicates that uneven distribution across all chromosomes appears through the outcrossing of compatible lineages and asexual reproduction-resulted relevant heterozygosity loss. In addition, we revealed a pericentric inversion caused by microhomology-mediated end joining in chromosome 16, potentially involving the positive selection of the SSU1 gene in ORF/promoter. The presence of genes such as the biotin prototrophic biosynthesis genes BIO1 and BIO6 or molasses toxicity resistance-related gene RTM1, as well as two copies of invertases, etc. reveals a phenotypic impact on industrial fermentation. Moreover, we identified numerous truncated ORFs in A1015 strain caused by non-triple insertions from tandem duplications, suggesting a unique genome evolution in the present industrial strain for molasses. Taken together, this study helps better understanding the genomic evolution of industrial S. cerevisiae for molasses fermentation.

TnpB is a protein encoded by a transposon and serves as a key component in the prokaryotic OMEGA system. It is predicted to be the “ancestor” of the Cas12 protein in the CRISPR system. TnpB is a programmable RNA-guided DNA endonuclease, which uses ωRNA molecules to guide the binding and cleavage of target DNA. Compared to proteins like Cas9 and Cas12, TnpB is smaller in size, consisting of approximately 400 amino acids. This smaller size offers an advantage in cellular delivery efficiency, as a single viral particle can carry it and facilitate its entry into the cell nucleus, where the genomic DNA is located. This article provides a detailed discussion of TnpB’s structure, function, its relationship with other gene-editing systems, and its potential applications in gene editing, offering a comprehensive reference for further research and application of TnpB.

According to the information available today, all types of microorganisms have common mechanisms for regulating the activity of virulence factors by the secondary messenger cAMP. They have been studied best in human and animal pathogens. At the same time, microorganisms that differ in specialization and habitat conditions, such as phytopathogens and mutualists, have mechanisms controlled by cAMP and adenylate cyclases that are fundamentally different from those in animal pathogens. The level of study of these processes in microorganisms of different specializations is uneven. This review attempts to systematize the available literature data and conduct a comparative analysis.

Alternative splicing (AS) is a non-canonical gene splicing process that allows a single gene to synthesise multiple protein isoforms and enhance a variety of protein functions. In this study, the involvement of AS in the generation of plant resistance to abiotic stresses was investigated using the VaCPK26 calcium-dependent protein kinase (CPK) gene, which is responsible for the resistance of Vitis amurensis Rupr. grapes to soil salinity and drought. The level of VaCPK26 transcription in grape leaves was studied under the influence of different environmental factors. Under low temperature exposure, in addition to the full-length VaCPK26 transcript, a short-spliced VaCPK26s1 transcript was obtained that lacked the 2nd exon out of the 7 exons that make up the full-length VaCPK26. Recombinant VaCPK26 increased the resistance of grape cells to salt stress and drought, and overexpression of the spliced VaCPK26s1 transcript in V. amurensis grape cell cultures had no effect on resistance to the stresses tested. These results show that AS can lead to the loss of properties of spliced transcripts characteristic of the original full-length form, which is important for complete understanding of the biological functions of CPK and alternative splicing.

In recent decades, the interest in Emericellopsis genus as producers of bioactive molecules has increased significantly due to the isolation of new compounds with potential pharmaceutical applications. Evaluation of the spectrum of antibiotic activity has allowed us to choose a promising producer of a new antibacterial compound, the strain Emericellopsis sp. E102 derived from saline soils. Strain E102, based on molecular and phylogenetic constructions, is allocated to a separate clade within the marine clade of Emericellopsis and is presumably a new species. The ethyl acetate extract of the E102 strain demonstrated significant efficacy at a concentration of 1000 μg/mL, resulting in the inhibition zones of 20.3–30.0 mm in size against Escherichia coli ATCC 25922; Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 700603, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212. The high-performance liquid chromatography analysis identified a compound with monoisotopic mass of the substance 724.5 g/mol. Using the Chemcalc.org service, the most probable gross formulas of the required component were determined. Based on the presented calculations, there is a high probability that the substance has a sterane framework.

The effects of the neurotransmitters serotonin (5-НТ), histamine, dopamine (DA), norepinephrine (NE), and acetylcholine (ACh) at concentrations of 0.1–10 μM on the contents of chlorophylls (а and b) and carotenoids in strains IPPAS B-239 and BM-1 of the microalga Haematococcus lacustris are considered. In the strain H. lacustris BM-1, all tested neurotransmitters except serotonin were found to stimulate carotenoid formation with an increase in the carotenoid content in the cells. The stimulatory effect was quite significant with acetylcholine and especially histamine and was manifested less with dopamine and norepinephrine. Carotenoid formation by strain IPPAS H-239 was only stimulated by acetylcholine and, to a lesser extent, by norepinephrine. The other neurotransmitters inhibited carotenoid formation. The total chlorophyll a and b content increased in the presence of all tested neurotransmitters except serotonin in strain BM-1. As for strain IPPAS H-239, its chlorophyll content was increased by acetylcholine and norepinephrine, whereas histamine and serotonin lowered the chlorophyll content. It is suggested that the tested neurotransmitters influence the vegetative cell—palmelloid cell—encysted cell transition, fixing it at the intermediate brown palmelloid stage characterized by significant chlorophyll and carotenoid contents.