Cloning and Direct Evolution of a Novel 7-O-Glycosyltransferase from Cucurbita moschata and Its Application in the Efficient Biocatalytic Synthesis of Luteolin-7-O-glucoside.

Luteolin-7-O-glucoside(L7G), a glycosylation product of luteolin, is present in a variety of foods, vegetables, and medicinal herbs and is commonly used in dietary supplements due to its health benefits. Meanwhile, luteolin-7-O-glucoside is an indicator component for the quality control of honeysuckle in the pharmacopoeia. However, its low content in plants has hindered its use in animal pharmacological studies and clinical practice. In this study, a novel 7-O-glycosyltransferase CmGT from Cucurbita moschata was cloned, which could efficiently convert luteolin into luteolin-7-O-glucoside under optimal conditions (40 °C and pH 8.5). To further improve the catalytic efficiency of CmGT, a 3D structure of CmGT was constructed, and directed evolution was performed. The mutant CmGT-S16A-T80W was obtained by using alanine scanning and iterative saturation mutagenesis. This mutant exhibited a kcat/Km value of 772 s-1·M-1, which was 3.16-fold of the wild-type enzyme CmGT. Finally, by introducing a soluble tag and UDPG synthesis pathway, the strain BXC was able to convert 1.25 g/L of luteolin into 1.91 g/L of luteolin-7-O-glucoside under optimal conditions, achieving a molar conversion rate of 96% and a space-time yield of 27.08 mg/L/h. This study provides an efficient method for the biosynthesis of luteolin-7-O-glucoside, which holds broad application prospects in the food and pharmaceutical industry.

Efficient and green production of flavone-5-O-glycosides by glycosyltransferases in Escherichia coli.

O-Glycosylflavonoids exhibit diverse biological activities but their low content in plants is difficult to extract and isolate, and chemical synthesis steps are cumbersome, which are harmful to the environment. Therefore, the biosynthesis of O-glycosylflavonoids represents a green and sustainable alternative strategy, with glycosyltransferases playing a crucial role in this process. However, there are few studies on flavone 5-O-glycosyltransferases, which limits the synthesis of rare flavone 5-O glycosides by microorganisms. In this study, we characterized a highly regioselectivity flavone 5-O glycosyltransferase from Panicum hallii. Site-directed mutagenesis at residue P141 switches glucosylation to xylosylation. Using a combinatorial strategy of metabolic engineering, we generated a series of Escherichia coli recombinant strains to biocatalyze glycosylation of the typical flavone apigenin. Ultimately, further optimization of transformation conditions, apigenin-5-O-glucoside and apigenin-5-O-xyloside were biosynthesized for the first time so far, and the yields were 1490 mg/L and 1210 mg/L, respectively. This study provides a biotechnological component for the biosynthesis of flavone-5-O-glycosides, and established a green and sustainable approach for the industrial production of high-value O-glycosylflavones by engineering, which lays a foundation for their further development and application in food and pharmaceutical fields.

Observing the clinical efficacy of combined serum microneedle therapy for moderate to severe androgenetic alopecia in scalp repair.

OBJECTIVE: In this study, the safety and efficacy of scalp repair serum microneedles combined with oral drug administration and topical medication were investigated for the treatment of moderate to severe androgenetic alopecia. METHODS: Twenty patients, consisting of 4 males and 16 females, who sought treatment for moderate to severe androgenetic alopecia at our hair medicine research center alopecia specialty clinic between August and December 2022 were randomly selected for the study. Male patients underwent oral administration of finasteride topical application of 5% minoxidil, and biweekly scalp repair serum microneedle therapy. Female patients were administered spironolactone or Diane-35 orally and applied 2% minoxidil topically, paired with biweekly scalp repair serum microneedle therapy sessions. After seven treatments, the scalp repair serum microneedle was discontinued, but oral administration and topical applications were continued, followed by a 1-month follow-up. Using a hair dermoscopy, hair follicles in a fixed region on the top of the head were manually counted per unit area to evaluate the hair restoration status of the patients quantitatively. RESULTS: All 20 patients completed 3 months of combined therapy and a 1-month follow-up. On average, the patients experienced an increase of 42.6 hairs, with an efficiency rate of 100%. Significant differences were observed in hair count between any two of the first seven treatments (p < 0.001). A significant negative correlation was discovered between the initial pre-treatment hair count and the total improvement of hair (p < 0.001), indicating that the greater the degree of hair loss before treatment, the more pronounced the improvement. CONCLUSION: Scalp repair serum microneedle combined therapy in moderate to severe androgenetic alopecia significantly reduces the number of microneedle treatments required, enhances treatment efficacy, and improves therapeutic outcomes.

Carotenoid Cleavage Dioxygenase 1 and Its Application for the Production of C13-Apocarotenoids in Microbial Cell Factories: A Review.

C13-apocarotenoids are naturally derived from the C9-C10 (C9'-C10') double-bond cleavage of carotenoids by carotenoid cleavage dioxygenases (CCDs). As high-value flavors and fragrances in the food and cosmetic industries, the sustainable production of C13-apocarotenoids is emerging in microbial cell factories by the carotenoid cleavage dioxygenase 1 (CCD1) subfamily. However, the commercialization of microbial-based C13-apocarotenoids is still limited by the poor performance of CCD1, which severely constrains its conversion efficiency from precursor carotenoids. This review focuses on the classification of CCDs and their cleavage modes for carotenoids to generate corresponding apocarotenoids. We then emphatically discuss the advances for C13-apocarotenoid biosynthesis in microbial cell factories with various strategies, including optimization of CCD1 expression, improvement of CCD1's catalytic activity and substrate specificity, strengthening of substrate channeling, and development of oleaginous microbial hosts, which have been verified to increase the conversion rate from carotenoids. Lastly, the current challenges and future directions will be discussed to enhance CCDs' application for C13-apocarotenoids biomanufacturing.

Antioxidant activity of a polysaccharide produced by Chaetomium globosum CGMCC 6882.

In present work, a polysaccharide (GCP-WS) was successfully produced by Chaetomium globosum CGMCC 6882 from wheat straw. Monosaccharide composition of GCP-WS was rhamnose, glucosamine, galactose, glucose, xylose, fructose and glucuronic acid in a molar ratio of 21.46:1.58:1.11:55.15:36.37:7.04:7.34. Meanwhile, molecular weight of GCP-WS was 3.538 × 104 Da with a polydispersity of 1.043. Antioxidant assays revealed GCP-WS had strong scavenging effects on DPPH radical, ABTS radical, superoxide anions and hydroxyl radical in a dose-dependent manner. Results displayed that at the concentration of 5 mg/mL, the corresponding scavenging abilities of GCP-WS reached 83.08 ±â€¯2.58%, 85.69 ±â€¯1.62%, 79.38 ±â€¯2.03% and 81.39 ±â€¯1.47%, respectively. GCP-WS shows the potential for development as an effective antioxidant agent.

Anti-diabetic activity evaluation of a polysaccharide extracted from Gynostemma pentaphyllum.

In current study, a polysaccharide (GPP) was successfully extracted from Gynostemma pentaphyllum herb. Monosaccharide composition of GPP was rhamnose, arabinose, galactose, glucose, xylose, mannose, galacturonic acid and glucuronic acid in a molar ratio of 4.11: 7.34: 13.31: 20.99: 1.07: 0.91: 4.75: 0.36. Molecular weight and polydispersity (Mw/Mn) of GPP were 4.070 × 104 Da and 1.037, respectively. Primary structure features of GPP were determined to be a polysaccharide by FT-IR and NMR. Fasting blood sugar of diabetic mice decreased from 17.56 mmol/L to 7.42 mmol/L by orally administration of 0.5 mL GPP (1 mg/mL) for 30 days. GPP exhibited a dose-dependent inhibition effect on α-glucosidase activity. Moreover, GPP could inhibit the glucose absorption and affect the protein expression of GLUT2, but not the protein expression of SGLT1. These results indicated GPP could be used as an effective ingredient to prevent and cure diabetes.