Ginsenoside Rh2(S) is well-known for its therapeutic potential against diverse conditions, including some cancers, inflammation, and diabetes. The enzymatic activity of uridine diphosphate glycosyltransferase 51 (UGT51) from Saccharomyces cerevisiae plays a pivotal role in the glycosylation process between UDP-glucose (donor) and protopanaxadiol (acceptor), to form ginsenoside Rh2. However, the catalytic efficiency of the UGT51 has remained a challenging task. To this end, we employed site-directed mutagenesis on UGT51 to improve its catalytic efficiency for enhanced production of ginsenoside Rh2. The mutated structure, featuring four key mutations (E805A, S998A, R1031A, and L1032A), exhibited heightened stability, binding affinity, and active site accessibility for protopanaxadiol (PPD) compared to the wild type. Under in vitro conditions, three mutants (E805A, R1031A, and L1032A) demonstrated 10%, 58%, and 65% higher enzymatic activities compared to the wild strain. Notably, the double mutant R1031A/L1032A exhibited an 85% increase in activity. Employing a fed-batch technology with PPD as the substrate yielded a Rh2 production of 4.663 g/L. The molecular dynamics (MD) simulations were employed to investigate the movements and dynamic dynamics of UGT51 mutations and PPD complexes. The root mean square deviation (RMSD) analysis revealed substantial alterations in structural conformation, particularly in the R1031A/L1032A mutations, correlating with boosted catalytic efficiency. Furthermore, the root mean square fluctuation (RMSF) simulation study aligned with both the RMSD and the solvent-accessible surface area (SASA) analyses. The computationally guided site-directed mutagenesis approach holds promise for extending its application to the development of commercially significant enzymes.
- Klíčová slova
- Fed-batch technology, Ginsenoside Rh2, MD simulations, Site-directed mutagenesis, Uridine diphosphate glycosyltransferase 51,
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The advancement of nanotechnology underscores the imperative need for establishing in silico predictive models to assess safety, particularly in the context of chronic respiratory afflictions such as lung fibrosis, a pathogenic transformation that is irreversible. While the compilation of predictive descriptors is pivotal for in silico model development, key features specifically tailored for predicting lung fibrosis remain elusive. This study aimed to uncover the essential predictive descriptors governing nanoparticle-induced pulmonary fibrosis. METHODS: We conducted a comprehensive analysis of the trajectory of metal oxide nanoparticles (MeONPs) within pulmonary systems. Two biological media (simulated lung fluid and phagolysosomal simulated fluid) and two cell lines (macrophages and epithelial cells) were meticulously chosen to scrutinize MeONP behaviors. Their interactions with MeONPs, also referred to as nano-bio interactions, can lead to alterations in the properties of the MeONPs as well as specific cellular responses. Physicochemical properties of MeONPs were assessed in biological media. The impact of MeONPs on cell membranes, lysosomes, mitochondria, and cytoplasmic components was evaluated using fluorescent probes, colorimetric enzyme substrates, and ELISA. The fibrogenic potential of MeONPs in mouse lungs was assessed by examining collagen deposition and growth factor release. Random forest classification was employed for analyzing in chemico, in vitro and in vivo data to identify predictive descriptors. RESULTS: The nano-bio interactions induced diverse changes in the 4 characteristics of MeONPs and had variable effects on the 14 cellular functions, which were quantitatively evaluated in chemico and in vitro. Among these 18 quantitative features, seven features were found to play key roles in predicting the pro-fibrogenic potential of MeONPs. Notably, IL-1β was identified as the most important feature, contributing 27.8% to the model's prediction. Mitochondrial activity (specifically NADH levels) in macrophages followed closely with a contribution of 17.6%. The remaining five key features include TGF-β1 release and NADH levels in epithelial cells, dissolution in lysosomal simulated fluids, zeta potential, and the hydrodynamic size of MeONPs. CONCLUSIONS: The pro-fibrogenic potential of MeONPs can be predicted by combination of key features at nano-bio interfaces, simulating their behavior and interactions within the lung environment. Among the 18 quantitative features, a combination of seven in chemico and in vitro descriptors could be leveraged to predict lung fibrosis in animals. Our findings offer crucial insights for developing in silico predictive models for nano-induced pulmonary fibrosis.
- Klíčová slova
- biotransformation, lung fibrosis, nanosafety, nanotoxicity, predictive toxicology,
- MeSH
- buňky A549 MeSH
- kovové nanočástice * toxicita chemie MeSH
- lidé MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- plíce účinky léků patologie metabolismus MeSH
- plicní fibróza * chemicky indukované metabolismus patologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Hepatic fibrosis progresses concomitantly with a variety of biomechanical alternations, especially increased liver stiffness. These biomechanical alterations have long been considered as pathological consequences. Recently, growing evidence proposes that these alternations result in the fibrotic biomechanical microenvironment, which drives the activation of hepatic stellate cells (HSCs). Here, an inorganic ascorbic acid-oxidase (AAO) mimicking nanozyme loaded with liquiritigenin (LQ) is developed to trigger remodeling of the fibrotic biomechanical microenvironment. The AAO mimicking nanozyme is able to consume intracellular ascorbic acid, thereby impeding collagen I deposition by reducing its availability. Simultaneously, LQ inhibits the transcription of lysyl oxidase like 2 (LOXL2), thus impeding collagen I crosslinking. Through its synergistic activities, the prepared nanosystem efficiently restores the fibrotic biomechanical microenvironment to a near-normal physiological condition, promoting the quiescence of HSCs and regression of fibrosis. This strategy of remodeling the fibrotic biomechanical microenvironment, akin to "pulling the rug out from under", effectively treats hepatic fibrosis in mice, thereby highlighting the importance of tissue biomechanics and providing a potential approach to improve hepatic fibrosis treatment.
- Klíčová slova
- biomechanical microenvironment, collagen I, hepatic fibrosis, hepatic stellate cell quiescence,
- MeSH
- biomechanika MeSH
- buněčné mikroprostředí účinky léků MeSH
- flavanony farmakologie chemie MeSH
- jaterní cirhóza * farmakoterapie metabolismus patologie MeSH
- jaterní hvězdicovité buňky * metabolismus cytologie účinky léků MeSH
- kolagen typu I metabolismus MeSH
- kyselina askorbová * farmakologie metabolismus chemie MeSH
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- flavanony MeSH
- kolagen typu I MeSH
- kyselina askorbová * MeSH
Fresnel incoherent correlation holography (FINCH) was a milestone in incoherent holography. In this roadmap, two pathways, namely the development of FINCH and applications of FINCH explored by many prominent research groups, are discussed. The current state-of-the-art FINCH technology, challenges, and future perspectives of FINCH technology as recognized by a diverse group of researchers contributing to different facets of research in FINCH have been presented.
- Klíčová slova
- Fresnel incoherent correlation holography, color holography, computational coherent superposition, digital holographic microscopy, digital holography, fluorescence microscopy, incoherent holography, lattice light-sheet holography, metasurfaces, multiplexed imaging, phase-shifting interferometry, single-molecule localization microscopy,
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Thuricin 4AJ1, produced by Bacillus thuringiensis strain 4AJ1, showed inhibition activity against Bacillus cereus 0938 and ATCC 10987. It began to appear in the stationary phase and reached its maximum activity level of 209.958 U at 18 h against B. cereus 0938 and 285.689 U at 24 h against B. cereus ATCC 10987. Tricine-SDS-PAGE results showed that the partly purified thuricin 4AJ1 was about 6.5 kDa. The molecular weights of the known B. thuringiensis bacteriocins and the ones obtained by the two mainstream websites for predicting bacteriocins were inconsistent with the size of the thuricin 4AJ1, indicating that the bacteriocin obtained in this study may have a novel structure. Based on the biochemical properties, the thuricin 4AJ1 activities increased after treatment with proteinase K and lipase II, and were not affected by a-amylase, catalase, α-chymotrypsin VII and α-chymotrypsin II. It was heat tolerant, being active up to 90º C. In the pH 3-10 range, it maintained most of its activity. Finally, the sensitivity of the strain 4AJ1 to commonly used antibiotics was tested. In view of its stability and antibacterial activity, thuricin 4AJ1 may be applied as a food biopreservative.
- Klíčová slova
- Agar spot assay, Bacillus cereus, Bacillus thuringiensis, Thuricin, Well diffusion method,
- MeSH
- antibakteriální látky farmakologie MeSH
- Bacillus cereus účinky léků MeSH
- Bacillus thuringiensis chemie metabolismus MeSH
- bakteriociny chemie izolace a purifikace farmakologie MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- molekulová hmotnost MeSH
- potravinářská mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antibakteriální látky MeSH
- bakteriociny MeSH
- thuricin MeSH Prohlížeč
Microbial contamination poses a great threat to aviation system security through mechanisms such as microbiologically influenced corrosion (MIC), fuel filter clogging, and fuel deterioration. In this study, a survey of microbial contamination in aviation fuel obtained from aircraft fuel tanks was performed to test the relationship between microbial contamination and aircraft service life. The contaminating microorganisms were counted, isolated, identified, and subjected to preliminary characterization. A low risk of microbial contamination in the selected samples was confirmed, and there was no significant difference in the counts between culturable bacteria and fungi (p > 0.05). Phylogenetic analysis tree indicated that the diversity of culturable microorganisms was rather low, with 17 bacterial isolates belonging to 13 genera and 12 fungal isolates belonging to 5 genera. No yeast was isolated. The growth characteristics of these isolates indicated that the aircraft fuel tanks harbored various microorganisms that were able to utilize the aviation fuel as a source of carbon and energy. Meanwhile, some isolates caused emulsification and produced acid. The conclusions of this study were that various hazardous microorganisms can root in aircraft aviation fuel tanks. There was no relationship between microbial contamination and aircraft service life (p > 0.05), and continuous good maintenance suppressed microbial proliferation.
- MeSH
- Bacteria klasifikace genetika růst a vývoj izolace a purifikace MeSH
- benzin analýza mikrobiologie MeSH
- fylogeneze MeSH
- houby klasifikace genetika růst a vývoj izolace a purifikace MeSH
- letadla MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- benzin MeSH
Mastitis in dairy cows is generally considered to be the most expensive disease for dairy farmers worldwide. The overuse of antibiotics is a major problem in the treatment of bovine mastitis, and bacteriophage therapy is expected to provide an alternative treatment. The primary aim of this study was to evaluate the efficacy of a phage cocktail against mastitis in a mouse model. First, a Staphylococcus aureus strain was isolated from milk samples taken from mastitis cows from dairy farms in Xinjiang, China, and it was designated as Sau-XJ-21. Next, two phages (designated as vBSM-A1 and vBSP-A2) with strong lytic activity against Sau-XJ-21 were isolated from mixed sewage samples collected from three cattle farms in Xinjiang. Phages vBSM-A1 and vBSP-A2 were identified as members of the Myoviridae and Podoviridae families, respectively. The two phages exhibited a wide range of hosts, especially phage vBSM-A1. To evaluate the effectiveness of the two phages in the treatment against mastitis, female lactating mice were used 10-14 days after giving births. The mice were divided into six groups; one group was kept as healthy control, while the remaining five groups were inoculated with the isolated S. aureus strain to induce mastitis. Four hours after bacterial inoculation, mice in these groups were injected with 25 μL phosphate buffer saline (negative control), ceftiofur sodium (positive control), or phage, either individually or as a cocktail. The mice were sacrificed 20 h later, and the mammary glands were removed and subjected to further analysis, including the quantitation of colony-forming units (CFU), plaque-forming units (PFU), and gross macroscopic as well as histopathology observation. Mice with induced mastitis exhibited significantly improved mastitic pathology and decreased bacterial counts after they had been given phage treatments, with the phage cocktail being more superior than either phage alone. Furthermore, the cocktail treatment also maintained the highest intramammary phage titer without spreading systemically. The effectiveness of the phage cocktail was comparable to that produced by ceftiofur sodium. According to the data obtained for the mouse model of mastitis, phage therapy could be considered as an innovative alternative to antibiotics for the treatment of bovine mastitis.
- MeSH
- bakteriofágy fyziologie MeSH
- fágová terapie metody veterinární MeSH
- mastitida skotu mikrobiologie terapie MeSH
- mléko mikrobiologie MeSH
- Myoviridae fyziologie MeSH
- myši MeSH
- Podoviridae fyziologie MeSH
- skot MeSH
- stafylokokové infekce mikrobiologie veterinární MeSH
- Staphylococcus aureus fyziologie virologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- skot MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- Geografické názvy
- Čína MeSH
Recent chlorophyll-a fluorescence yield measurements, using single-turnover saturating flashes (STSFs), have revealed the involvement of a rate-limiting step in the reactions following the charge separation induced by the first flash. As also shown here, in diuron-inhibited PSII core complexes isolated from Thermosynechococcus vulcanus the fluorescence maximum could only be reached by a train of STSFs. In order to elucidate the origin of the fluorescence yield increments in STSF series, we performed transient absorption measurements at 819 nm, reflecting the photooxidation and re-reduction kinetics of the primary electron donor P680. Upon single flash excitation of the dark-adapted sample, the decay kinetics could be described with lifetimes of 17 ns (∼50%) and 167 ns (∼30%), and a longer-lived component (∼20%). This kinetics are attributed to re-reduction of P680•+ by the donor side of PSII. In contrast, upon second-flash (with Δt between 5 μs and 100 ms) or repetitive excitation, the 819 nm absorption changes decayed with lifetimes of about 2 ns (∼60%) and 10 ns (∼30%), attributed to recombination of the primary radical pair P680•+ Pheo•- , and a small longer-lived component (∼10%). These data confirm that only the first STSF is capable of generating stable charge separation - leading to the reduction of QA ; and thus, the fluorescence yield increments elicited by the consecutive flashes must have a different physical origin. Our double-flash experiments indicate that the rate-limiting steps, detected by chlorophyll-a fluorescence, are not correlated with the turnover of P680.
In this work, a facile two-step strategy is adopted to construct hierarchical polyaniline/NiCo-layered double hydroxide (PANI/NiCo-LDH) core-shell composite nanofiber networks on carbon cloth (CC). Three-dimensional (3D) porous PANI nanofiber networks are firstly uniformly anchored on CC by in-situ oxidative polymerization, followed by growth of NiCo-LDH nanoflakes on the crosslinked PANI framework via electrochemical deposition. The morphology and electrochemical properties of PANI/NiCo-LDH composites are controlled by the deposition time of LDH. Benefiting from rapid electron transport and ion diffusion, the well-defined PANI/NiCo-LDH hierarchical composite with 200 s deposition of LDH delivers a large capacitance of 1845 F g-1 at 0.5 A g-1 and excellent cycling stability of 82% capacitance retention after 5000 cycles at a very high current density of 10.0 A g-1. Furthermore, an asymmetric supercapacitor (ASC) assembled with PANI/NiCo-LDH as a positive electrode and activated carbon (AC) as a negative electrode exhibits a high capacitance of 147.2 F g-1 in a potential range from 0 to 1.5 V and superior energy density of 46.0 Wh kg-1 at a power density of 351.6 W kg-1.
- Klíčová slova
- core-shell structure, electrochemical performance, layered double hydroxides, polyaniline nanofibers, supercapacitor,
- Publikační typ
- časopisecké články MeSH
Climate is widely recognised as an important determinant of the latitudinal diversity gradient. However, most existing studies make no distinction between direct and indirect effects of climate, which substantially hinders our understanding of how climate constrains biodiversity globally. Using data from 35 large forest plots, we test hypothesised relationships amongst climate, topography, forest structural attributes (stem abundance, tree size variation and stand basal area) and tree species richness to better understand drivers of latitudinal tree diversity patterns. Climate influences tree richness both directly, with more species in warm, moist, aseasonal climates and indirectly, with more species at higher stem abundance. These results imply direct limitation of species diversity by climatic stress and more rapid (co-)evolution and narrower niche partitioning in warm climates. They also support the idea that increased numbers of individuals associated with high primary productivity are partitioned to support a greater number of species.
- Klíčová slova
- CTFS-ForestGEO, Climate tolerance hypothesis, latitudinal diversity gradient, more-individuals hypothesis, species-energy relationship, structural equation modelling,
- MeSH
- biodiverzita * MeSH
- podnebí MeSH
- stromy * MeSH
- Publikační typ
- dopisy MeSH
