Search Results (968)

Ene-reductases (ERs) are enzymes known for catalyzing the asymmetric hydrogenation of activated alkenes. Among these, old yellow enzyme (OYE) ERs have been the most extensively studied for biocatalytic applications due to their dependence on NADH or NADPH as electron donors. These flavin-containing enzymes are highly enantio- and stereoselective, making them attractive biocatalysts for industrial use. To discover novel thermostable OYE-type ERs, we explored genomes of thermophilic fungi. Five genes encoding ERs were selected and expressed in Escherichia coli, namely AtOYE (from Aspergillus thermomutatus), CtOYE (from Chaetomium thermophilum), LtOYE (from Lachancea thermotolerans), OpOYE (from Ogatae polymorpha), and TtOYE (from Thermothielavioides terrestris). Each enzyme was purified as a soluble FMN-containing protein, allowing detailed characterization. All ERs exhibited a preference for NADPH, with AtOYE showing the broadest substrate range. Moreover, all the enzymes showed activity toward maleimide and p-benzoquinone, with TtOYE presenting the highest catalytic efficiency. The optimal pH for enzyme activity was between 6 and 7 and the enzymes displayed notable solvent tolerance and thermostability, with CtOYE and OpOYE showing the highest stability (T_m > 60 °C). Additionally, all enzymes converted R-carvone into (R,R)-dihydrocarvone. In summary, this study contributes to expanding the toolbox of robust ERs. Full article

Polyvinyl alcohol (PVA)-based pH-responsive color indicators were developed using red cabbage anthocyanin (Anth) copigmented with gelatin and gallic acid (GA). The indicator prepared with gelatin and GA (GA/gelatin/Anth/PVA) was highly resistant to light exposure. GA/gelatin/Anth/PVA exhibited distinct color changes in pH 2–11 buffer solutions and stable color indication in acidic and neutral solid systems (pH 2 and 7) at 97% relative humidity. GA/gelatin/Anth/PVA exhibited the highest sensitivity to dimethylamine, followed by ammonia and trimethylamine. The addition of gelatin and GA facilitated hydrogen bonding, which enhanced thermal stability and water solubility without compromising tensile properties. A color change from purple to blue signaled spoilage when total volatile basic nitrogen values for beef and squid reached 21.0 and 37.8 mg/100 g, respectively. The GA/gelatin/Anth/PVA indicator shows potential for indicating the freshness of raw beef. Full article

Background: Natural isoflavones are recognized for their diverse pharmacological activities; however, their low aqueous solubility presents a significant challenge for further development. Here, we aimed to develop a cocrystal of formononetin (FMN) to improve its solubility. Methods: The formononetin-imidazole (FMN-IMD) cocrystal was prepared using liquid-assisted grinding method. The prepared cocrystal was identified through a thermal analysis of physical mixtures with various coformers. FTIR and solid-state NMR confirmed the presence of hydrogen bonds and π-π interactions in the FMN-IMD cocrystal. Results: The solubility of FMN-IMD was two to three times higher than that of crystalline FMN. The FMN-IMD cocrystal showed a 4.93-fold increase in the Cmax value and a 3.58-fold increase in the AUC compared to FMN after oral administration in rats. There were no changes in the PXRD of the FMN-IMD cocrystal after six months of storage at 40 °C. Conclusions: Thus, the FMN-IMD cocrystal is proposed as an effective solid form for oral delivery, offering enhanced solubility and physical stability. Full article

Characterized by its exceptional electrical, physical, and chemical properties, 1-phenyl-1-xylylethane (PXE) insulating oil finds extensive application in the realm of power capacitor insulation. In this study, molecular simulation is employed to investigate the reactivity of PXE insulating oil molecules and the impact of temperature on water diffusion behavior in PXE insulating oil, as well as its solubility. The findings demonstrate a higher propensity for hydrogen atoms in nucleophilic and electrophilic positions within PXE insulating oil molecules to interact with water molecules. The inclusion of a temperature field enhances the Brownian motion of water molecules and improves their diffusion ability within the oil. Furthermore, the temperature field diminishes the interaction force between water molecules and the oil medium. Under the influence of this temperature field, there is an increase in the free volume fraction of PXE insulating oil, leading to a weakening effect on hydrogen bonds between oxygen and hydrogen atoms within PXE insulating oil. Additionally, with increasing temperature, there is an elevation in moisture solubility within insulating oil, resulting in a transition from a suspended state to a dissolved state. Full article

Plants are continuously exposed to environmental challenges, including pollutants, pesticides, and heavy metals, collectively termed xenobiotics. These substances induce oxidative stress by generating reactive oxygen species (ROS), which can damage cellular components such as lipids, proteins, and nucleic acids. To counteract this, plants have evolved complex metabolic pathways to detoxify and process these harmful compounds. Oxidative stress in plants primarily arises from the overproduction of hydrogen peroxide (H₂O₂), superoxide anions (O₂^•−), singlet oxygen (¹O₂), and hydroxyl radicals (^•OH), by-products of metabolic activities such as photosynthesis and respiration. The presence of xenobiotics leads to a notable increase in ROS, which can result in cellular damage and metabolic disruption. To combat this, plants have developed a strong antioxidant defense mechanism that includes enzymatic antioxidants that work together to eliminate ROS, thereby reducing their harmful effects. In addition to enzymatic defenses, plants also synthesize various non-enzymatic antioxidants, including flavonoids, phenolic acids, and vitamins. These compounds effectively neutralize ROS and help regenerate other antioxidants, offering extensive protection against oxidative stress. The metabolism of xenobiotic substances in plants occurs in three stages: the first involves modification, which refers to the chemical alteration of xenobiotics to make them less harmful. The second involves conjugation, where the modified xenobiotics are combined with other substances to increase their solubility, facilitating their elimination from the plant. The third stage involves compartmentalization, which is the storage or isolation of conjugated xenobiotics in specific parts of the plant, helping to prevent damage to vital cellular functions. Secondary metabolites found in plants, such as alkaloids, terpenoids, and flavonoids, play a vital role in detoxification and the defense against oxidative stress. Gaining a deeper understanding of the oxidative mechanisms and the pathways of xenobiotic metabolism in plants is essential, as this knowledge can lead to the formulation of plant-derived strategies aimed at alleviating the effects of environmental pollution and enhancing human health by improving detoxification and antioxidant capabilities, as discussed in this review. Full article

In recent decades, the frequency of flooding has increased as a result of global climate change. Flooding has become one of the major abiotic stresses that seriously affect the growth and development of plants. Mulberry (Morus alba L.) is an important economic tree in China. Flooding stress is among the most severe abiotic stresses that affect the production of mulberry. However, the physiological and molecular biological mechanisms of mulberry responses to flooding stress are still unclear. In the present study, reactive oxygen species (ROS) metabolism, antioxidant mechanism, and plant hormones in mulberry associated with the response to flooding stress were investigated using physiological and transcriptomic analysis methods. The results showed significant increases in the production rate of superoxide anion (O₂^•−) and the content of hydrogen peroxide (H₂O₂) in leaves on the 5th day of flooding stress. This led to membrane lipid peroxidation and elevated malondialdehyde (MDA) levels. Antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) exhibited enhanced activities initially, followed by fluctuations. The ascorbic acid–glutathione (AsA-GSH) cycle played a crucial role in scavenging ROS, promoting the reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH). Transcriptomic analysis revealed the up-regulation of the gene-encoding antioxidant enzymes (APX, MDHAR, GPX, GR, GST) involved in ROS scavenging and stress tolerance mechanisms. Jasmonic acid (JA) levels and the expression of JA synthesis-related genes increased significantly in mulberry leaves under flooding stress. This activation of the JA signaling pathway contributed to the plant’s adaptability to flooding conditions. Proline (Pro) and soluble sugar (SS) contents increased notably in response to flooding stress. Proline helped maintain cell turgor and protected enzymes and membranes from damage, while soluble sugars supported anaerobic respiration and energy supply. However, soluble protein (SP) content decreased, suggesting inhibition of protein synthesis. The study provides insights into mulberry’s flooding tolerance mechanisms, guiding future molecular breeding efforts. This summary captures the key findings and implications of the study on mulberry’s response to flooding stress, focusing on physiological and molecular mechanisms identified in the research. Full article

Formic acid is reported to act as a food preservative and feed additive, but its effects on controlling postharvest physiological deterioration (PPD) development in cassava are unclear. In this study, we assessed the effectiveness of different concentrations of formic acid in attenuating PPD occurrence in fresh-cut cassava. The results showed that the concentration of 0.1% (v/v) formic acid could significantly delay the occurrence of PPD, and that the higher the concentration of formic acid supplied, the later the occurrence of PPD symptoms. The physiological and biochemical analysis of 0.5%-formic-acid-treated cassava slices revealed that formic acid decreased the degradation of starch, inhibited the accumulation of hydrogen peroxide (H₂O₂), malondialdehyde (MDA), and water-soluble pectin in cassava slices with PPD development, and increased the activities of the antioxidant enzymes ascorbate peroxidase (APX) and glutathione reductase (GR). A microscopic observation showed that the formic acid treatment inhibited the enlargement of the intercellular space during the cassava PPD process, which suggests that the formation of an intercellular layer of the cell wall was inhibited by formic acid. This study thus revealed the mechanism used by formic acid to extend the cassava shelf life; however, a detailed evaluation of the possible side effects on, for example, the cyanide content will be needed to categorically ensure the safety of this method. Full article

The effects of salt–enzyme–alkali progressive tenderization treatments on porcine cortical conformation and collagen properties were investigated, and their effectiveness and mechanisms were analyzed. The tenderization treatment comprised three treatment stages: CaCl₂ (25 °C/0–30 min), papain (35 °C/30–78 min), and Na₂CO₃ (25 °C/78–120 min). The textural, microscopic, and collagenous properties (content, solubility, and structure) of pork skin were determined at the 0th, 30th, 60th, 90th, and 120th min of the treatment process. The results showed that the shear force, hardness, and chewability of the skin decreased significantly (p < 0.05), and the elasticity exhibited a gradual increase with the progression of tenderization. The content and solubility of collagen showed no significant change at the CaCl₂ treatment stage. However, the soluble collagen content increased, the insoluble collagen content decreased, and the collagen solubility increased by 18.04% during the subsequent treatment with papain and Na₂CO₃. Meanwhile, the scanning electron microscopy results revealed that the regular, wavy structure of the pig skin collagen fibers gradually disappeared during the CaCl₂ treatment stage, the overall structure revealed expansion, and the surface microscopic pores gradually increased during the papain and Na₂CO₃ treatment stages. The findings of the Fourier transform infrared spectroscopy analysis indicated that the hydrogen bonding interactions between the collagen molecules and the C=O, N-H and C-N bonds in the subunit structure of collagen were substantially altered during treatment and that the breakage of amino acid chains and reduction in structural ordering became more pronounced with prolonged treatment. In the tertiary structure, the maximum emission wavelength was blue-shifted and then red-shifted, and the fluorescence intensity was gradually weakened. The surface hydrophobicity was slowly increased. The salt–enzyme–alkali tenderization treatment considerably improved the physical properties and texture of edible pork skins by dissolving collagen fibers and destroying the structure of collagen and its interaction force. Full article

This study explores the in vitro antifungal effects of nerol, a linear acyclic monoterpene alcohol of plant origin, on Fusarium oxysporum, Pestalotiopsis neglecta, and Valsa mali. To further investigate the antifungal mechanism of nerol against F. oxysporum, we examined changes in mycelial morphology and cell membrane integrity-related indices, as well as the activities of antioxidant and pathogenicity-related enzymes. The results demonstrated that nerol exhibited significant concentration-dependent inhibition of mycelial growth in all three fungi, with EC₅₀ values of 0.46 μL/mL for F. oxysporum, 1.81 μL/mL for P. neglecta, and 1.26 μL/mL for V. mali, with the strongest antifungal activity observed against F. oxysporum. Scanning electron microscopy revealed that nerol severely disrupted the mycelial structure of F. oxysporum, causing deformation, swelling, and even rupture. Treatment with 0.04 μL/mL nerol led to significant leakage of soluble proteins and intracellular ions in F. oxysporum, and the Na⁺/K⁺-ATPase activity was reduced to 28.02% of the control, indicating enhanced membrane permeability. The elevated levels of hydrogen peroxide and malondialdehyde, along with propidium iodide staining of treated microconidia, further confirmed cell membrane disruption caused by nerol. Additionally, after 12 h of exposure to 0.04 μL/mL nerol, the activity of superoxide dismutase in F. oxysporum decreased to 55.81% of the control, and the activities of catalase and peroxidase were also significantly inhibited. Nerol markedly reduced the activities of pathogenicity-related enzymes, such as endo-1,4-β-D-glucanase, polygalacturonase, and pectin lyase, affecting fungal growth and virulence. In conclusion, nerol disrupts the cell membrane integrity and permeability of F. oxysporum, reduces its virulence, and ultimately inhibits fungal growth, highlighting its potential as an alternative to chemical fungicides for controlling F. oxysporum. Full article

Vase life directly affects the ornamental value of cut flowers, and extending vase life has been a research focus in the floriculture industry. The antioxidant and antimicrobial properties of Nano-Se provide a new direction to extend the life of cut-flower vase life. In order to explore the postharvest quality of Nano-Se on cut-flower roses, this study treated cut-flower roses with different concentrations of Nano-Se (200, 400, and 600 mM) using a commercially available preservative solution as a base solution. The results showed that appropriate concentrations of Nano-Se significantly increased the vase life of cut-flower roses and helped to maintain high petal moisture content. Nano-Se at concentrations of 200, 400, and 600 mM extended the vase life of cut roses by 4.3, 5.7, and 3.7 d, respectively. As the vase period extended, the Nano-Se treatment group effectively delayed the decline in antioxidant enzyme activities such as peroxidase (POD) and catalase (CAT), maintained the soluble sugar (SS) and soluble protein (SP) contents in the cut roses, and inhibited the production of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), reducing their accumulation. A correlation analysis of the physiological indexes of cut roses showed that vase life was positively correlated with POD and CAT activities, SS and SP contents, and total phenolic acid content and negatively correlated with MDA and H₂O₂ contents. This study provides a solid theoretical basis for the diversification of preservatives and the development of new preservatives for fresh-cut roses, which is expected to provide significant economic benefits. Full article

The synthesis of enantiomeric forms of D-amino acids can be achieved by a two-step “hydantoinase process” based on the sequential catalysis of substrates by specific enzymes, D-carbamoylase and D-hydantoinase. Here, we describe the structural features of D-carbamoylase from Pseudomonas, the encoded gene of which was chemically synthesized and cloned into Escherichia coli. A significant fraction of the overexpressed recombinant protein forms insoluble inclusion bodies, which are partially converted to a soluble state upon treatment with N-lauroylsarcosine or upon incubation of cells at 28 °C. Purified His-tagged protein exhibits the highest activity towards N-carbamoyl-D-alanine and N-carbamoyl-D-tryptophan. Comprehensive virtual analysis of the interactions of bulky carbamylated amino acids with D-carbamoylase provided valuable information. Molecular docking analysis revealed the location of the substrate binding site in the three-dimensional structure of D-carbamoylase. Molecular dynamics simulations showed that the binding pocket of the enzyme in complex with N-carbamoyl-D-tryptophan was stabilized within 100 nanoseconds. The free energy data showed that Arg176 and Asn173 formed hydrogen bonds between the enzyme and substrates. The studies of D-carbamoylases and the properties of our previously obtained D-hydantoinase suggest the possibility of developing a harmonized biotechnological process for the production of new drugs and peptide hormones. Full article

The global energy market is shifting toward renewable, sustainable, and low-carbon hydrogen energy due to global environmental issues, such as rising carbon dioxide emissions, climate change, and global warming. Currently, a majority of hydrogen demands are achieved by steam methane reforming and other conventional processes, which, again, are very carbon-intensive methods, and the hydrogen produced by them needs to be purified prior to their application. Hence, researchers are continuously endeavoring to develop sustainable and efficient methods for hydrogen generation and purification. Membrane-based gas-separation technologies were proven to be more efficient than conventional technologies. This review explores the transition from conventional separation techniques, such as pressure swing adsorption and cryogenic distillation, to advanced membrane-based technologies with high selectivity and efficiency for hydrogen purification. Major emphasis is placed on various membrane materials and their corresponding membrane performance. First, we discuss various metal membranes, including dense, alloyed, and amorphous metal membranes, which exhibit high hydrogen solubility and selectivity. Further, various inorganic membranes, such as zeolites, silica, and CMSMs, are also discussed. Major emphasis is placed on the development of polymeric materials and membranes for the selective separation of hydrogen from CH₄, CO₂, and N₂. In addition, cutting-edge mixed-matrix membranes are also delineated, which involve the incorporation of inorganic fillers to improve performance. This review provides a comprehensive overview of advancements in gas-separation membranes and membrane materials in terms of hydrogen selectivity, permeability, and durability in practical applications. By analyzing various conventional and advanced technologies, this review provides a comprehensive material perspective on hydrogen separation membranes, thereby endorsing hydrogen energy for a sustainable future. Full article

The solubilization of poorly water-soluble natural bioactive compounds remains a significant challenge. This study aims to design a ternary inclusion system to enhance the solubility of the poorly water-soluble compound Neohesperidin (NH). Soluble ternary cyclodextrin complexations (t-CDs) containing NH, 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), and meglumine (MEG) were prepared and optimized. The optimized t-CDs were further characterized using Scanning Electron Microscopy (SEM), Powder X-ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), and molecular docking (MD) techniques. The results suggested that NH formed was associated with MEG through hydrogen bonds with MEG, and was subsequently incorporated into the hydrophobic cavity of HP-β-CD, which may be a key factor in improving its solubility. The solubility of NH in water at 37 °C increased significantly from 0.16 mg/mL to 5.81 mg/mL in the optimized t-CDs (NH/MEG/HP-β-CD). Full article

Fish protein hydrolysates (FPHs) were obtained from different fish sources using a combination of microbial enzymes. The industrially produced FPHs from blue whiting (Micromesistius poutassou) and sprat (Sprattus sprattus) were compared to freeze-dried FPHs generated in-house from hake (Merluccius merluccius) and mackerel (Scomber scombrus) in terms of their physicochemical composition and functionality. Significant differences (p < 0.05) were observed in the protein, moisture, and ash contents of the FPHs, with the majority having high levels of protein (73.24–89.31%). Fractions that were more extensively hydrolysed exhibited a high solubility index (74.05–98.99%) at different pHs. Blue whiting protein hydrolysate-B (BWPH-B) had the highest foaming capacity at pH 4 (146.98 ± 4.28%) and foam stability over 5 min (90–100%) at pH 4, 6, and 8. The emulsifying capacity ranged from 61.11–108.90 m²/g, while emulsion stability was 37.82–76.99% at 0.5% (w/v) concentration. In terms of peptide bioactivity, sprat protein hydrolysate (SPH) had the strongest overall reducing power. The highest Cu²⁺ chelating activity was exhibited by hake protein hydrolysate (HPH) and mackerel protein hydrolysate (MPH), with IC₅₀ values of 0.66 and 0.78 mg protein/mL, respectively, while blue whiting protein hydrolysate-A (BWPH-A) had the highest activity against Fe²⁺ (IC₅₀ = 1.89 mg protein/mL). SPH scavenged DPPH and ABTS radicals best with IC₅₀ values of 0.73 and 2.76 mg protein/mL, respectively. All FPHs displayed noteworthy scavenging activity against hydroxyl radicals, with IC₅₀ values ranging from 0.48–3.46 mg protein/mL. SPH and MPH showed the highest scavenging potential against superoxide radicals with IC₅₀ values of 1.75 and 2.53 mg protein/mL and against hydrogen peroxide with 2.22 and 3.66 mg protein/mL, respectively. While inhibition of α-glucosidase was not observed, the IC₅₀ values against α-amylase ranged from 8.81–18.42 mg protein/mL, with SPH displaying the highest activity. The stability of FPHs following simulated gastrointestinal digestion (SGID) showed an irregular trend. Overall, the findings suggest that marine-derived protein hydrolysates may serve as good sources of natural nutraceuticals with antioxidant and antidiabetic properties. Full article

Extrusion processing of plasticized cassava starch, a prominent industrial crop, with chemical additives offers a thermo-mechanical approach to modify starch structures through physical and chemical interactions. This research investigates the interaction and morphology of thermoplastic cassava starch (TPS) blended with tetrasodium pyrophosphate (Na₄P₂O₇), sodium tripolyphosphate (Na₅P₃O₁₀), sodium hexametaphosphate (Na₆(PO₃)₆), sodium erythorbate (C₆H₇O₆Na), and sodium nitrite (NaNO₂) via twin-screw extrusion. The effects of these additives on the chemical structure, thermal profile, water absorption, and solubility of the TPS were examined. The high temperature and shearing forces within the extruder disrupted hydrogen bonding at α-(1-4) and α-(1-6) glycosidic linkages within anhydroglucose units. Na₄P₂O₇, Na₅P₃O₁₀ and Na₆(PO₃)₆ induced starch phosphorylation, while ¹H NMR and ATR-FTIR analyses revealed that C₆H₇O₆Na and NaNO₂ caused starch hydrolysis. These additives hindered starch recrystallization, resulting in higher amorphous fractions that subsequently influenced the thermal properties and stability of the extruded TPS. Furthermore, the type and content of the added modifier influenced the water absorption and solubility of the TPS due to varying levels of interaction. These modified starch materials exhibited enhanced antimicrobial properties against Escherichia coli and Staphylococcus aureus in polyester blends fabricated via extrusion, with nitrite demonstrating the most potent antimicrobial efficacy. These findings suggest that starch modification via either phosphorylation or acid hydrolysis impacts the thermal properties, morphology, and hydrophilicity of extruded cassava TPS. Full article