Search Results (1,631)

The granulation of pomelo (Citrus maxima) juice sacs severely compromises fruit quality and is closely associated with lignin accumulation, a process catalyzed by peroxidases (PODs). Analysis of ‘Sanhong’ pomelo juice sacs collected 175–215 days after flowering revealed that bound peroxidase (BPOD) activity paralleled changes in lignin content, suggesting a potential role for BPOD in lignin biosynthesis. A total of 71 CmPOD genes were identified in the pomelo genome through integrated HMMER and BLAST analyses. Among them, CmPOD52 was selected for functional characterization based on its alkaline peroxidase properties, absence of a CE domain, predicted extracellular localization, and gradually increasing expression pattern revealed by RT-qPCR. Its transient overexpression in ‘Sanhong’ pomelo juice sacs for 36 h increased BPOD activity 2.06-fold (p < 0.01) compared to the empty vector control, indicating that CmPOD52 may be a BPOD gene. The recombinant CmPOD52 protein was expressed in a prokaryotic system, purified, and used in enzymatic assays with sinapyl alcohol as the substrate. The recombinant CmPOD52 protein, assayed at 272 nm with controls (substrate-only blank and heat-inactivated protein), showed an activity of 13.67 ± 0.9 U. The experimental group showed new products, identified by mass spectrometry as sinapyl alcohol dimers, thus suggesting that the recombinant protein catalyzes the dehydrogenation and polymerization of sinapyl alcohol monomers. This study identified CmPOD52, a gene potentially involved in lignin polymerization in pomelo juice sacs, offering a key candidate for further in vivo validation. Full article

Intrinsically disordered regions enable transcription factors (TFs) to undergo structural changes upon ligand binding, facilitating the transduction of environmental signals into gene expression. In this study, we applied molecular modeling methods to explore the hypothesis that unstructured inter-domain and subdomain linkers in bacterial TFs can function as sensors for carbohydrate signaling molecules. We combined molecular dynamics simulations and carbohydrate docking to analyze six repressors with GntR-type DNA-binding domains, including UxuR, GntR and FarR from Escherichia coli, as well as AraR, NagR and YydK from Bacillus subtilis. Protein models obtained from different time points of the dynamic simulations were subjected to sequential carbohydrate docking. We found that the inter-domain linker of the UxuR monomer binds D-fructuronate, D-galacturonate, D-glucose, and D-glucuronate with an affinity comparable to nonspecific interactions. However, these ligands formed multimolecular clusters, a feature absent in the UxuR dimer, suggesting that protein dimerization may depend on linker occupancy by cellular carbohydrates. D-glucose interacted with linkers connecting subdomains of the LacI/GalR-type E-domains in GntR and AraR, forming hydrogen bonds that connected distant structural modules of the proteins, while in NagR, FarR and YydK, it bridged the inter-domain linkers and a β-sheet within the HutC-type E-domains. Hence, our results establish flexible linkers as pivotal metabolic sensors that directly integrate nutritional cues to alter gene expression in bacteria. Full article

This work was inspired by quercetin, a natural bioflavonoid with well-known neuroprotective properties. We synthesized a new functional monomer, 3-acryloxy-3′,4′,5,7-tetramethylquercetin 1, and used it to prepare, for the first time, a molecularly imprinted polymer (MIP) selective for donepezil, the main drug used in Alzheimer’s disease therapy. The polymer was designed to be fluorescent and responsive to pH changes, aiming for controlled drug release. The optimized MIP-4, produced from a 1:1 mixture of the monomer 1 and acrylic acid, was characterized by FTIR-ATR, fluorescence spectroscopy, SEM, and DLS, confirming its chemical composition, morphology, particle size distribution and zeta potential. Adsorption studies showed higher donepezil binding capacity for MIP than for NIP, highlighting the polymer’s selective recognition. In vitro release experiments at pH 3, 5.5, and 7 revealed a pH-dependent behaviour, with nearly 98% cumulative donepezil release at pH 7. The polymer was non-cytotoxic and successfully released donepezil in in vitro assays, enabling effective inhibition of eeAChE. These results provide a proof of concept supporting the potential of quercetin-derived fluorescent molecularly imprinted polymers as selective and stimuli-responsive platforms for donepezil delivery. Full article

This study utilizes QM/MM Born–Oppenheimer Molecular Dynamics in order to model the process of intermolecular binding between reduced graphene oxide (rGO) and butadiene–acrylonitrile copolymer (PBDAN) with a monomer ratio of 2:1. This research aims to elucidate the structural reasons behind the enhancing properties of the substrate, focusing on the polymer matrix. The behavior of each phase was examined and discussed. More importantly, the intermolecular interactions within the interphase zone of adsorption were investigated on an atomic scale. We found and characterized 58 such instances, grouped into hydrogen bonds and three types of stacking: π–π, σ–π, and σ–n. Each occurrence was analyzed through the use of radial distribution functions. Five spontaneous chemical processes within the rGO nanoparticle were modeled and characterized. Two of them were found to provide stabilization only within the substrate, while the rest are relevant for the overall constitution of the heteromaterial. Perhaps most intriguing is the process of self-repair as part of the vacancy defect. This occurs entirely within the carbon frame of the rGO layer. We believe our results to be of importance for a large set of ligand materials, mostly those which contain unsaturated bonds and electronegative atoms. Full article

Commercially available resorufin was shown to function as an organic photocatalyst for visible-light-induced aqueous radical polymerization under low-irradiance illumination. Polymers with narrow molecular weight distributions and high monomer conversions were successfully synthesized from acrylate and acrylamide monomers. The photopolymerization catalyzed by resorufin was consistent with a reductive quenching mechanism. Good temporal control of the reaction was achieved by toggling visible light irradiation. Full article

Chemokines play a central role in orchestrating neutrophil recruitment from the bloodstream and determining their effector functions at sites of infection. Chemokine activity is determined by three key properties: reversible monomer–dimer equilibrium, binding to glycosaminoglycans (GAGs), and signaling through the GPCR class of receptors CXCR1 and CXCR2. In this study, we investigated the structural basis of CXCL8 monomer and dimer binding to GAG chondroitin sulfate (CS) using nuclear magnetic resonance (NMR) spectroscopy, docking, and molecular dynamics (MD) measurements. Our studies reveal that both the monomer and dimer use essentially the same set of basic residues for binding, that the interface is extensive, that the dimer is the high-affinity CS ligand, and that the CS-binding residues form a contiguous surface within a monomer. Several of these residues also participate in receptor interactions, suggesting that CS-bound CXCL8 is likely impaired in its ability to bind receptors. Notably, we observe that the same basic residues are involved in binding CS and heparin/heparan sulfate, even though these GAGs differ in backbone structures and sulfation patterns. We conclude that the strategic distribution and topology of basic residues on the CXCL8 scaffold enable engagement with diverse GAG structures, which likely allows fine-tuning receptor signaling to regulate neutrophil trafficking and effector functions. Full article

As a non-invasive diagnostic technique, evolved gas analysis (EGA) holds significant value in assessing the insulation conditions of critical equipment such as power cables. Current analytical methods face two major challenges: insulation materials may undergo multiple aging mechanisms simultaneously, leading to interfering characteristic gases; and traditional approaches lack the multi-label recognition capability to address concurrent fault patterns when processing mixed-gas data. These limitations hinder the accuracy and comprehensiveness of insulation condition assessment, underscoring the urgent need for intelligent analytical methods. This study proposes a deep convolutional neural network (DCNN)-based multi-label classification framework to accurately identify the gas generation characteristics of five typical power cable insulation materials—ethylene propylene diene monomer (EPDM), ethylene-vinyl acetate copolymer (EVA), silicone rubber (SR), polyamide (PA), and cross-linked polyethylene (XLPE)—under fault conditions. The method leverages concentration data of six characteristic gases (CO₂, C₂H₄, C₂H₆, CH₄, CO, and H₂), integrating modern data analysis and deep learning techniques, including logarithmic transformation, Z-score normalization, multi-scale convolution, residual connections, channel attention mechanisms, and weighted binary cross-entropy loss functions, to enable simultaneous prediction of multiple degradation states or concurrent fault pattern combinations. By constructing a gas dataset covering diverse materials and operating conditions and conducting comparative experiments to validate the proposed DCNN model’s performance, the results demonstrate that the model can effectively learn material-specific gas generation patterns and accurately identify complex label co-occurrence scenarios. This approach provides technical support for improving the accuracy of insulation condition assessment in power cable equipment. Full article

Agricultural biomass has potential as a renewable and versatile carbon feedstock for developing eco-friendly and biodegradable polymers capable of replacing conventional petrochemical plastics. To address the growing environmental concerns associated with plastic waste and carbon emissions, lignocellulosic residues, edible crop by-products, and algal biomass were utilized as sustainable raw materials. These biomasses provided carbohydrate-, lipid-, and lignin-rich fractions that were deconstructed through optimised physical, chemical, and enzymatic pretreatments to yield fermentable intermediates, such as reducing sugars, organic acids, and fatty acids. The intermediates were subsequently converted through tailored microbial fermentation processes into biopolymer precursors, primarily polyhydroxyalkanoates (PHAs) and lactate-based monomers. The resulting monomers underwent polymerization via polycondensation and ring-opening reactions to produce high-performance biodegradable plastics with tunable structural and mechanical properties. Additionally, the direct extraction and modification of naturally occurring polymers, such as starch, cellulose, and lignin, were explored to develop blended and functionalized bioplastic formulations. Comparative evaluation revealed that these biomass-derived polymers possess favourable physical strength, thermal stability, and biodegradability under composting conditions. Life-cycle evaluation further indicated a significant reduction in greenhouse gas emissions and improved carbon recycling compared to fossil-derived counterparts. The study demonstrates that integrating agricultural residues into bioplastic production not only enhances waste valorization and rural bioeconomy but also supports sustainable material innovation for packaging, farming, and consumer goods industries. These findings position agriculture-based biodegradable polymers as a critical component of circular bioeconomy strategies, contributing to reduced plastic pollution and improved environmental sustainability. Full article

Plasmodesmata (PDs) are enriched in sphingolipids and sterols, creating a specialized environment for regulatory proteins like plasmodesmata-localized proteins (PDLPs). How PDLPs regulate PD function in a specific lipid environment remains poorly understood. Here, we provide a unique insight from the interaction network of two different PDLPs together with sphingolipids and propose a concept that PDLPs form homo- or hetero-dimers only in the presence of sphingolipids. Located in the detergent resistance region, PDLP7 demonstrated the ability to influence the sphingolipid composition in PD-enriched fraction, particularly the GIPC content, and finally, modulating the membrane order. The presence of sphingolipids, in turn, affected the oligomeric state of PDLP7 in membranes. The PDLP7 recombinant protein existed as a monomer in vitro, but it formed self-aggregates in yeast and plant cells. We further examined PDLP5, another known phytosphinganine (t18:0)-specific binding PDLP, alongside PDLP7, and confirmed a similar interaction pattern: no direct interaction was observed in vitro, but interactions were noted in vivo. Co-overexpression of the two disrupted their PD localization and induced the upregulation of pathogenesis-related protein 1 (PR1). In summary, we gained insights into the network of PDLPs with lipids and propose that PDLPs were under precise regulation during plant development and stress responses. Full article

Hybrid fluorinated copolymers containing POSS moieties along with fluorinated homopolymers were synthesized via organocatalyzed atom transfer radical (co)polymerization (O-ATRP) of fluoroalkyl methacrylate (FMA) and a POSS-based monomer (IBSS) using perylene as a photocatalyst. Linear and four- and eight-armed star-shaped (co)polymers in a wide range of molecular weights with M_n(SEC) up to 53,100 g/mol for poly(FMA), 22,700 g/mol for poly(IBSS) and 87,300 g/mol for poly(FMA-co-IBSS) were successfully prepared. During polymerization, C–F activation was found to induce chain transfer and branching reactions, contributing to structural diversity. A mechanism for chain transfer to the polymer resulting in branching was proposed, applying density functional theory (DFT). Films based on the obtained (co)polymers showed tunable morphology, high thermal stability (up to 306 °C) and hydrophobicity, with water contact angles reaching 98°. Full article

Catalytic coacervates, or droplet reactors, represent a forefront research area in chemistry and materials science. Despite advancements in this field, challenges persist in achieving liquid–liquid phase separation (LLPS) droplet compartmentalization and site-specific reactant recruitment/localization for reaction catalysis, similar to those within biological systems. Herein, we describe the catalytic coacervates for aqueous photo-RAFT in dilution, focusing on the site-specific recruitment/localization of ionized monomer with the aid of macromolecular crowding and confinement. Cooperative hydrogen-bonded interpolymer complexation (IPC) of imidazolium-copolymers initiates the ion-cluster formation. Further hierarchical inter-cluster complexation (ICC) leads to the LLPS droplet compartmentalization into charged dense-phase and neutral dilute-phase compartments. Site-specific recruitment and localization of the oppositely charged monomer into dense-phase compartments are achieved by salt-bridging molecular recognition. “Substantial DMA-dilution” (that is, macromolecular crowding) results in sustainable dense-phase catalytic sites within dilute-phase crowding surroundings, enabling reaction catalysis in dilution (<2% w/w monomer) to 97% conversion in 12 min. These findings underscore the key roles of macromolecular crowding and confinement in the tailorable LLPS droplet compartmentalization and also the site-specific reactant recruitment/localization essential for enzyme reaction catalysis, and provide practical guidelines for creating catalytic coacervates towards lifelike reaction functions. Full article

Background/Objectives. Antibiotic resistance is an escalating global health concern, highlighting the need for innovative antibacterial strategies beyond traditional drugs. GroEL, a highly conserved bacterial chaperonin essential for protein folding and stress tolerance, represents a promising but underexplored therapeutic target. This study aimed to identify short peptides capable of binding GroEL monomers and potentially altering their function, with the long-term goal of disrupting bacterial survival mechanisms. Methods. A phage display screening of a 12-mer peptide library was performed against purified GroEL monomers, yielding five candidate peptides (G1–G5). Their interactions with GroEL were analyzed through molecular docking and molecular dynamics simulations using three-dimensional GroEL structures (1MNF, 1XCK, 8S32). Stability of binding and interaction profiles were assessed through molecular dynamics-based analyses and MM/GBSA free energy calculations. Results. Peptides G4 and G5 displayed the most stable and energetically favorable interactions, with G4–8S32 showing the strongest binding (−116.68 kcal/mol). These peptides localized near inter-subunit interfaces, suggesting potential interference with GroEL oligomerization or allosteric transitions, which are critical for its biological function. Conclusions. Our findings demonstrate that short peptides can stably bind GroEL and potentially modulate its activity. Peptides G4 and G5 represent at our knowledge the first promising scaffolds for developing a novel class of peptide-based antibacterial agents targeting conserved chaperonin systems. This work introduces a new avenue that warrants further experimental validation. Full article

In this work, the one-pot catalytic reductive fractionation of C-lignin in castor shell powders to efficiently provide catechyl monomers was achieved by tandem metal triflate and Pd/C catalysis. The optimized Pd/C + In(OTf)₃ combination performed best and provided a 66.9 mg·g⁻¹ yield of corresponding aromatic monomers with the catechol selectivity as high as 95.4%. For the promotion effect of the Lewis acid species, the mechanism studied indicated that the introduction of In³⁺ could significantly promote the C–O bond cleavage in the LCC to release the C-lignin fragments from the solid lignocellulose and simultaneously accelerate the cleavage of the critical C_α/β–OAr linkage bond in C-lignin to release catechol monomers. In addition, performance differences highlight the cooperation and function-matching effect between the hydrogenation metals and the Lewis ion species, which can promote the high-value utilization of forestry and agricultural residues in chemical synthesis. Full article

White organic light-emitting diodes (OLEDs) offer a promising solution for next-generation lighting technologies and their ability to emit white light through various mechanisms make them an attractive option for illumination and display applications. Here, we design and prepare a series of N,N-difluorenevinylaniline-based small molecules and polymer, and realize white OLEDs based on these luminescent materials with combined blue monomer emission and orange electromer emission upon electronic excitation in the solution-processed devices. Impressively, the single-component nonconjugated polymer exhibits the best device performance, because the nonconjugated structure favors good solubility of the polymers, while the conjugated starburst unit functions as highly luminescent fluorophore in both single molecular and aggregated structures for the blue and orange emissions, respectively. Specifically, the non-doped solution-processed OLEDs achieve warm white electroluminescence with a maximum luminance of 1806 cd/m² and a maximum external quantum efficiency of 2.63%. And, the OLEDs based on the monomer also exhibit white electroluminescence with Commission Internationale de L’Eclairage coordinates of (0.30, 0.32). These results highlight a promising strategy for the material design and preparation of single-component nonconjugated polymers with rich emissive behaviors in solid states towards efficient and solution-processable white OLEDs. Full article

This research involved functionalizing polypropylene (PP) films with 2-(Diethylamino)ethyl methacrylate (DEAEM), a monomer that responds to both temperature and pH. For this, Gamma-ray irradiation was used at a dose rate of 11.75 kGy h⁻¹, doses ranging from 30 to 100 kGy, and a monomer concentration of 50% (v/v). The modified films (PP-g-DEAEM) were characterized by thermal analysis, FTIR-ATR, swelling, and contact angle. Confirming that the films were successfully grafted with DEAEM, improving the wettability of the pristine PP films, with a critical pH of 5.6 and a temperature response at 45.7 °C. Subsequently, the films were subjected to ciprofloxacin loading and release, and their in vitro efficacy against the E. coli strain was assessed using the Kirby-Bauer method. This work suggests potential applications in biomedical devices; however, further studies are needed. Full article