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Skin wound healing is a dynamic and complex process that involves multiple physiological and cellular events. Grape seed proanthocyanidins (GSP) have strong anti-oxidation and elimination of oxygen free radicals, and have been shown to significantly promote wound healing, but the underlying mechanism remains unclear. Studies have indicated that reactive oxygen species (ROS) acts as an upstream signal to induce mitophagy, suggesting that GSP can regulate mitophagy through the signal pathway. This study aimed to investigate whether GSP regulates mitophagy by down-regulating oxidative stress to promote wound healing. In vivo , GSP treatment accelerated wound healing, granulation tissue formation, collagen deposition, and angiogenesis in mice. Moreover, GSP down-regulated ROS levels and promoted the expression of antioxidant proteins by up-regulating the expression of p-JNK/FOXO3a protein, thereby regulating the expression of mitophagy-related proteins. In vitro , 4 μg/mL GSP showed no apparent toxic effects on cells and effectively reduce the oxidative stress damage of cells induced by H 2 O 2. Western blot and superoxide anion fluorescence probe further confirmed that GSP effectively reduced Dihydroethidium content and up-regulated the expression of antioxidant proteins by activation of p-JNK/FOXO3a protein expression, thereby regulating mitophagy. Taken together, the findings from in vitro and in vivo experiments provide new insights into the promotion of wound healing by GSP. Schematic illustration of how GSP promotes wound healing in mouse skin by regulating endothelial mitophagy through the p-JNK/FOXO3A/ROS signaling pathway. Mice were administered GSP via gavage, which upregulated p-JNK protein. Phosphorylated JNK protein activated FOXO3a protein, which in turn upregulated antioxidant proteins (MnSOD and catalase) to reduce ROS levels. The decrease in ROS level regulated mitophagy and accelerated wound healing in mice. [Display omitted] • Grape seed proanthocyanidins (GSP) promotes wound healing. • GSP reduces oxidative stress to regulate mitochondrial autophagy. • The p-JNK/FOXO3a/ROS signaling pathway is regulated by GSP. [ABSTRACT FROM AUTHOR]

Medium-chain fatty acids (C6–C10) have attracted much attention recently for their unique properties compared to their long-chain counterparts, including low melting points and relatively higher carbon conversion yield. Thioesterase enzymes, which can catalyze the hydrolysis of acyl-ACP (acyl carrier protein) to release free fatty acids (FAs), regulate both overall FA yields and acyl chain length distributions in bacterial and yeast fermentation cultures. These enzymes typically prefer longer chain substrates. Herein, seeking to increase bacterial production of MCFAs, we conducted structure-guided mutational screening of multiple residues in the substrate-binding pocket of the E. coli thioesterase enzyme 'TesA. Confirming our hypothesis that enhancing substrate selectivity for medium-chain acyl substrates would promote overall MCFA production, we found that replacement of residues lining the bottom of the pocket with more hydrophobic residues strongly promoted the C8 substrate selectivity of 'TesA. Specifically, two rounds of saturation mutagenesis led to the identification of the 'TesARD−2 variant that exhibited a 133-fold increase in selectivity for the C8-ACP substrate as compared to C16-ACP substrate. Moreover, the recombinant expression of this variant in an E. coli strain with a blocked β -oxidation pathway led to a 1030% increase in the in vivo octanoic acid (C8) production titer. When this strain was fermented in a 5-L fed-batch bioreactor, it produced 2.7 g/L of free C8 (45%, molar fraction) and 7.9 g/L of total free FAs, which is the highest-to-date free C8 titer to date reported using the E. coli type II fatty acid synthetic pathway. Thus, reshaping the substrate binding pocket of a bacterial thioesterase enzyme by manipulating the hydrophobicity of multiple residues altered the substrate selectivity and therefore fatty acid product distributions in cells. Our study demonstrates the relevance of this strategy for increasing titers of industrially attractive MCFAs as fermentation products. • Semi-rational design of 'TesA thioesterase was performed to reshape the acyl binding pocket. • The best variant exhibits a 133-fold increase in selectivity for C8-ACP as compared to C16-ACP substrate. • The highest octanoic acid (2.7 g/L) titer was achieved in E. coli type II fatty acid synthetic pathway. [ABSTRACT FROM AUTHOR]

Ideation is a source of innovation and creativity, and is commonly used in early stages of engineering design processes. This paper proposes an integrated approach for enhancing design ideation by applying artificial intelligence and data mining techniques. This approach consists of two models, a semantic ideation network and a visual concepts combination model, which provide inspiration semantically and visually based on computational creativity theory. The semantic ideation network aims to provoke new ideas by mining potential knowledge connections across multiple knowledge domains, and this was achieved by applying "step-forward" and "path-track" algorithms which assist in exploring forward given a concept and in tracking back the paths going from a departure concept through a destination concept. In the visual concepts combination model, a generative adversarial networks model is proposed for generating images which synthesize two distinct concepts. An implementation of these two models was developed and tested in a design case study, which indicated that the proposed approach is able to not only generate a variety of cross-domain concept associations but also advance the ideation process quickly and easily in terms of quantity and novelty. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • UGT51 catalyzes the transformation of glucose into varied sterols. • Complexes with donor substrate UDPG was solved and highlight key residues. • Molecular docking of cholesterol into UGT51 highlight key residues. • Comparison of UGT51 with M7_1 model revealed key factors for substrate specificity. Abstract Sterol glycosyltransferases catalyze the formation of a variety of glycosylated sterol derivatives and are involved in producing a plethora of bioactive natural products. To understand the molecular mechanism of sterol glycosyltransferases, we determined crystal structures of a sterol glycosyltransferase UGT51 from Saccharomyces cerevisiae. The structures of the UGT51 and its complex with uridine diphosphate glucose (UDPG) were solved at resolutions of 2.77 Å and 1.9 Å, respectively. The structural analysis revealed that a long hydrophobic cavity, 9.2 Å in width and 17.6 Å in length located at the N-terminal domain of UGT51, is suitable for the accommodation of sterol acceptor substrates. Furthermore, a short, conserved sequence of S847-M851 was identified at the bottom of the hydrophobic cavity, which might be the steroid binding site and play an important role for the UGT51 catalytic specificity towards sterols. Molecular docking simulations indicated that changed unique interaction network in mutant M7_1 (S801A/L802A/V804A/K812A/E816K/S849A/N892D), with an 1800-fold activity improvement toward an unnatural substrate protopanaxadiol (PPD), might influence its substrate preference. This study reported the first sterol glycosyltransferase structure, providing a molecular blueprint for generating tailored sterol glycosyltransferases as potential catalytic elements in synthetic biology. [ABSTRACT FROM AUTHOR]

The antimicrobial activity and stability of essential oils are increased in nanoemulsion formulations. One of the main disadvantages of using plant essential oils is their low solubility in water. Nanoemulsion formulations of essentials oils can increase their water solubilities and facilitate their interactions with microbial cell membranes, thereby facilitating cell lysis. In this study, cinnamon essential oil (CEO) nanoemulsions were prepared by high-pressure homogenization, using an orthogonal test design to optimize the preparation conditions. The stability of the nanoemulsions during storage and its antimicrobial activity against various foodborne pathogens were investigated. The results showed that during preparation, the homogenization pressures, oil phase ratio, and content of modified starch can affect the particle diameter of the emulsion. The incorporation of medium-chain triglycerides into the emulsion can significantly enhance the nanoemulsion stability and effectively reduce the particle size of the nanoemulsions. The CEO nanoemulsions inhibited the growth of different microbial strains, although Gram-negative bacteria were more sensitive to these nanoemulsions than Gram-positive bacteria. These results are of considerable significance for the research and innovation of natural food preservatives. • Cinnamon essential oilnanoemulsions were prepared by optimized preparation conditions. • Nanoemulsions with increased stability and reduced particle size were produced. • The cinnamon essential oil nanoemulsions had significant antimicrobial activity. • The stability of essential oils in nanoemulsions was increased compared to the pure form. [ABSTRACT FROM AUTHOR]

• The EGALC from Rhodococcus hoagii 103S shares high sequence identity (92.27%) with previously characterized EGALC from Rhodococcus equi. • The EGALC hydrolyzes 6-gala series glycosphingolipids. • The first crystal structure of EGALC to 1.2 Å resolution. • The conformation and length of Nβ8-Lα1 regions of EGCs are crucial for substrate specificity of EGCs. Endoglycoceramidases (EGCs) are family 5 glycoside hydrolases that catalyze hydrolysis of the glycosidic linkages between the oligosaccharide and ceramide moieties of glycosphingolipids. Three orthologs of EGCs, each with distinct substrate specificity, have been identified to date, including EGC-I, EGC-II, and EGALC. Although the structures of EGC-I and EGC-II have been reported, the substrate preference mechanism of EGC enzymes remains unclear. Here, we determined the crystal structure of EGALC from Rhodococcus hoagii 103S at a resolution of 1.20 Å. Distinct from EGC-I and EGC-II, which both have a tunnel-like substrate binding site, the structure of EGALC accommodates substrates in a long groove. Further, the oligosaccharide-binding region of groove could be divided into two small pockets that separately bind to the Gal1 and to the Gal3/Gla3 present in 6-gala series substrates. Structural and sequence comparisons of EGC enzymes revealed that the conformation and length of their Nβ8-Lα1 regions are crucial in determining the architectures of their specific substrate binding sites. Importantly, molecular docking analyses indicate that the substrate specificity of each EGC is mainly derived from the complementarity of its active site groove/tunnel with substrates adopting particular conformations. Our study provide insights for understanding the catalytic mechanism of EGALC, which will help protein engineering for improving the substrate preference and catalytic efficiency of EGC enzymes toward important glycosphingolipid substrates. [ABSTRACT FROM AUTHOR]