Glycosylation Products Research Articles

Computer-Aided Design of α-L-Rhamnosidase to Increase the Synthesis Efficiency of Icariside I.

Icariside I, the glycosylation product of icaritin, is a novel effective anti-cancer agent with immunological anti-tumor activity. However, very limited natural icariside I content hinders its direct extraction from plants. Therefore, we employed a computer-aided protein design strategy to improve the catalytic efficiency and substrate specificity of the α-L-rhamnosidase from Thermotoga petrophila DSM 13995, to provide a highly-efficient preparation method. Several beneficial mutants were obtained by expanding the active cavity. The catalytic efficiencies of all mutants were improved 16–200-fold compared with the wild-type TpeRha. The double-point mutant DH was the best mutant and showed the highest catalytic efficiency (k cat /K M : 193.52 s−1 M−1) against icariin, which was a 209.76-fold increase compared with the wild-type TpeRha. Besides, the single-point mutant H570A showed higher substrate specificity than that of the wild-type TpeRha in hydrolysis of different substrates. This study provides enzyme design strategies and principles for the hydrolysis of rhamnosyl natural products.

Ruthenium-Catalyzed Pyridine-Directed Aryl C-H Glycosylation with Glycosyl Chlorides.

Metal-catalyzed C-H glycosylation reactions with glycosyl chloride donors have emerged as a useful strategy for the synthesis of C-glycosides. Previously, palladium and nickel complexes were reported to catalyze C-H glycosylation reactions using amide-linked bidentate auxiliaries. Herein, a ruthenium-catalyzed ortho C-H glycosylation reaction of arenes with various glycosyl chloride donors using a monodentate pyridine directing group is developed. Preliminary mechanistic studies indicated that two-electron oxidative addition and reductive elimination of ruthenocycle intermediate led to the glycosylation products.

Low doses of advanced glycation end-products and fructosilation products promotes premature cell death of human cardiac cells and increases drug resistance of human breast cancer cells exposed to doxorubicin through NLRP3 and MyD88 pathways.

e24055 Background: Advanced glycosylation end-products (AGEs) are non-enzyme, protein glycosylation products caused by glucose-induced metabolic disorder, and play an important role in aging, cancer, metabolic syndrome and cardiovascular diseases. We aimed to assess whether AGEs and fructosilation products, such as methylglyoxal (MG) and N-carboxymethyllysine (N-CML) could increase susceptibility to cell damages induced by doxorubicin. Methods: Human cardiomyocytes were pre-exposed for 24h with low doses (50 mmol/L) of methylglyoxal (MG) or N-carboxymethyllysine (N-CML). After, cells were exposed to subclinical concentration of doxorubicin (at 100 and 200 nM) for 48 and 72h. After the incubation period, we performed the following tests: determination of cell viability, through analysis of mitochondrial dehydrogenase activity, study of lipid peroxidation (quantifying cellular Malondialdehyde and 4-hydroxynonenal), intracellular Ca2+ homeostasis. Moreover, pro-inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of peroxisome proliferator-activated receptor-α; mTORC1 Fox01/3a; transcriptional activation of p65/NF-κB and secretion of cytokines involved in cardiotoxicity (Interleukins 1β, 8, 6). Expression of p53 was also performed through western blot method. Results: Pre-exposure to methylglyoxal (MG) but especially to N-carboxymethyllysine (N-CML) increase cell mortality to doxorubicin of 48-53% compared to control. Pre-exposure to N-CML promotes premature death of cardiomyocytes to doxorubicin through NLRP3-driven pathways. Notably, MG and N-CML increased significantly the cardiotoxicity through NLRP3 inflammasome, Myd88 myddosome and cytochrome C-mediated apoptosis. Pre-exposure to N-CML and MG increase the secretion of interleukin-6 that increase cell apoptosis through a paracrine and autocrine mechanism. Induction of IL-6 reduces the expression of p53 resulting in the induction of the apoptotic process. Conclusions: These observations suggest that AGEs and fructosilation producs promotes premature cardiotoxicity of human cardiac cells exposed to doxorubicin by activation of NLRP3, Myd88-related pathways and downregulation of p53.

P131 LOW DOSES OF ADVANCED GLYCATION END–PRODUCTS AND FRUCTOSILATION PRODUCTS PROMOTES PREMATURE CELL DEATH OF HUMAN CARDIAC CELLS EXPOSED TO DOXORUBICIN VIA ACTIVATION OF NLRP3, MYD88 AND P53 DOWNREGULATION

Abstract Introduction Advanced glycosylation end–products (AGEs) are non–enzyme, protein glycosylation products caused by glucose–induced metabolic disorder, and play an important role in aging, cancer, metabolic syndrome and cardiovascular diseases. Purpose We aimed to assess whether AGEs and fructosilation products, such as methylglyoxal (MG) and N–carboxymethyllysine (N–CML) could increase susceptibility to cell damages induced by doxorubicin Methods Human cardiomyocytes were pre–exposed for 24h with low doses (50 mmol/L) of methylglyoxal (MG) or N–carboxymethyllysine (N–CML). After, cells were exposed to subclinical concentration of doxorubicin (at 100 and 200 nM) for 48 and 72h. After the incubation period, we performed the following tests: determination of cell viability, through analysis of mitochondrial dehydrogenase activity, study of lipid peroxidation (quantifying cellular Malondialdehyde and 4–hydroxynonenal), intracellular Ca2+ homeostasis. Moreover, pro–inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of peroxisome proliferator–activated receptor–α; mTORC1 Fox01/3a; transcriptional activation of p65/NF–κB and secretion of cytokines involved in cardiotoxicity (Interleukins 1β, 8, 6). Expression of p53 was also performed through western blot method Results Pre–exposure to methylglyoxal (MG) but especially to N–carboxymethyllysine (N–CML) increase cell mortality to doxorubicin of 48–53% compared to control. Pre–exposure to N–CML promotes premature death of cardiomyocytes to doxorubicin through NLRP3–driven pathways. Notably, MG and N–CML increased significantly the cardiotoxicity through NLRP3 inflammasome, Myd88 myddosome and cytochrome C–mediated apoptosis. Pre–exposure to N–CML and MG increase the secretion of interleukin–6 that increase cell apoptosis through a paracrine and autocrine mechanism. Induction of IL–6 reduces the expression of p53 resulting in the induction of the apoptotic process. Conclusion These observations suggest that AGEs and fructosilation producs promotes premature cardiotoxicity of human cardiac cells exposed to doxorubicin by activation of NLRP3, Myd88–related pathways and downregulation of p53.

Metabolite Profiling and Transcriptome Analysis Unveil the Mechanisms of Red-Heart Chinese Fir [Cunninghamia lanceolata (Lamb.) Hook] Heartwood Coloration.

Red-heart Chinese fir (Cunninghamia lanceolata) has the advantages of high density and attractive color, making it popular in the market. To date, most studies about stems of woody plants have only been reported at the cytological level because of few living cells. In this study, the xylem was successfully partitioned into three effective sampling areas: sapwood, transition zone, and heartwood. Secondary metabolites, cell survival, and differentially expressed genes in the three sampling areas were, respectively, investigated. First, we identified the phenylpropanoid and flavonoid pathways closely related to color. Based on the chemical structure of secondary metabolites in pathways, two notable directions had been found. Luteolin’s glycosylation products might be the key substances that regulated the color of heartwood in red-heart Chinese fir because of the 1,000-fold difference between red-heart and white-heart. We also found pinocembrin and pinobanksin in Chinese fir, which were rarely reported before. At the cytological level, we believed that the transition zone of red-heart Chinese fir was a critical region for color production because of the fewer living ray parenchyma cells. In addition, transcriptome and quantitative reverse transcription PCR (qRT-PCR) proved that genes regulating the entire phenylpropanoid pathway, upstream of the flavonoid pathway, and some glycosyltransferases were significantly upregulated in the transition zone of red-heart and then colored the heartwood by increasing metabolites. This is the first report on the color-related secondary metabolites regulated by differential genes in red-heart Chinese fir. This study will broaden our knowledge on the effects of metabolites on coloring woody plant xylems.

Effects of ultrasound-assisted glycosylation on the interface and foaming characteristics of ovotransferrin

Ovotransferrin (OVT) is one of the major functional proteins in egg white protein. Most of the industry only paid attention the biological activity of OVT in iron supplement, antibacterial and other aspects, few reports were carried out on its processing characteristics such as foaming, interfacial behavior such as emulsification and foaming, which was an important processing functional attribute affecting its application scenario. In this study, the effects of ultrasound-assisted glycosylation on the interface and foaming characteristics of OVT were investigated. The results showed that proper ultrasonic treatment had a significant effect on the structure and physicochemical properties of OVT glycosylation products. When ultrasonic treatment lasted for 20 min, the grafting degree of OVT was 20.98%, the particle size decreased and the absolute value of potential increased. The foaming ability of OVT increased first and then decreased after ultrasonic-assisted glycosylation treatment. The foaming ability of OVT increased from 43.54% to 96.73% and the foaming stability increased from 68.92% to 89.19% after ultrasonic-assisted glycosylation treatment for 20 min. The experimental study effectively discovered the effect of ultrasound-assisted glycosylation on the foaming property of OVT, and would provide important technical references for expanding its application in food, biology, medicine and other fields.

Critical Determinants in ER-Golgi Trafficking of Enzymes Involved in Glycosylation.

All living cells generate structurally complex and compositionally diverse spectra of glycans and glycoconjugates, critical for organismal evolution, development, functioning, defense, and survival. Glycosyltransferases (GTs) catalyze the glycosylation reaction between activated sugar and acceptor substrate to synthesize a wide variety of glycans. GTs are distributed among more than 130 gene families and are involved in metabolic processes, signal pathways, cell wall polysaccharide biosynthesis, cell development, and growth. Glycosylation mainly takes place in the endoplasmic reticulum (ER) and Golgi, where GTs and glycosidases involved in this process are distributed to different locations of these compartments and sequentially add or cleave various sugars to synthesize the final products of glycosylation. Therefore, delivery of these enzymes to the proper locations, the glycosylation sites, in the cell is essential and involves numerous secretory pathway components. This review presents the current state of knowledge about the mechanisms of protein trafficking between ER and Golgi. It describes what is known about the primary components of protein sorting machinery and trafficking, which are recognition sites on the proteins that are important for their interaction with the critical components of this machinery.

Stereoselective gem-C,B-Glycosylation via 1,2-Boronate Migration.

A novel protocol is established for the long-standing challenge of stereoselective geminal bisglycosylations of saccharides. The merger of PPh3 as a traceless glycosidic leaving group and 1,2-boronate migration enables the simultaneous introduction of C-C and C-B bonds at the anomeric stereogenic center of furanoses and pyranoses. The power of this method is showcased by a set of site-selective modifications of glycosylation products for the construction of bioactive conjugates and skeletons. A scarce metal-free 1,1-difunctionalization process of alkenes is also concomitantly demonstrated.

Circulating s-Endoglin concentrations in non-obese patients with gestational diabetes mellitus

The aim of this study was to compare maternal concentrations of soluble Endodlin (s-Endoglin) in women with gestational diabetes (GDM) and women with normal glucose tolerance (NGT) in pregnancy. Also, the association of insulin resistance markers and s-Endoglin was investigated. Forty patients complicated by GDM and forty gestational age-matched healthy pregnant women with NGT were included in the present study. s-Endoglin level was higher in patients with GDM compared with the control group (p .01). Besides a positive correlation was found between s-Endoglin and fasting glucose (r = 0.206, p = .057), insulin (r = 0.302, p = .005), HbA1c (r = 0.376, p < .01), HOMA-IR values (r = 0.283, p = .008) in pregnant women included in the study. s-Endoglin, as an anti-angiogenic marker seemed to have a role in pathogenesis and significantly associated with insulin resistance markers in non-obese GDM, thus may play important roles in the regulation of glucose hemostasis. Impact Statement What is already known on this subject? In women with GDM, hyperglycaemia induced glycosylation products might cause oxidative stress that may be subsequently involved in the release of inflammatory mediators, inducing angiogenesis What the results of this study add? s-Endoglin has an anti-angiogenic effect and is a useful marker of endothelial injury, activation of inflammation, senescence and oxidative stress, we speculate that it may be involved in the pathogenesis of GDM. What the implications are of these findings for clinical practice and/or further research? s-Endoglin seemed to have a role in the regulation of glucose hemostasis. Further exploration of novel factors like s-endoglin in the pathogenesis of GDM, is essential and valuable to develop new therapeutic strategies for this complex disease and its complications.

Exploring the Potential Pharmacological Mechanism of Hesperidin and Glucosyl Hesperidin against COVID-19 Based on Bioinformatics Analyses and Antiviral Assays.

The development of anti-COVID-19 drugs has become the top priority since the outbreak of the epidemic, and Traditional Chinese medicine plays an important role in reducing mortality. Here, hesperidin and its glycosylation product, glucosyl hesperidin were selected to determine their antiviral activity against SARS-CoV-2 due to their structural specificity as reported. To be specific, their binding ability with ACE2, M, S, RBD and N proteins were verified with both in silico and wet lab methods, i.e., molecular docking and binding affinity tests, including biolayer interferometry assay (BLI) and isothermal titration calorimetry assay (ITC). Moreover, systematic pharmacological analysis was conducted to reveal their pharmacological mechanism in treating COVID-19. Finally, their antiviral activity against SARS-CoV-2 was determined in vitro in a biosafety level 3 (BSL3) laboratory. The results demonstrated their outstanding binding affinity with ACE2, M, S and RBD proteins, while showed barely unobserved binding with N protein, indicating their key roles in influencing the invasion and early replication phase of SARS-CoV-2. In addition, both hesperidin and glucosyl hesperidin were shown to have a great impact on immune, inflammation and virus infection induced by COVID-19 according to the systematic pharmacological analysis. Moreover, the IC50s of hesperidin and glucosyl hesperidin against SARS-CoV-2 were further determined (51.5 [Formula: see text]M and 5.5 mM, respectively) with cell-based in vitro assay, suggesting their great anti-SARS-CoV-2 activity. All in all, present research was the first to verify the binding ability of hesperidin and glucosyl hesperidin with SARS-CoV-2 proteins with both in silico and wet-lab methods and proposed the possibility of applying hesperidin and glucosyl hesperidin to treat COVID-19.

Ab Initio Calculation Based Solvent System Selection in Silico for Counter-Current Chromatography: Separation of Resibufogenin Glycosylation Products

Ab Initio Calculation Based Solvent System Selection in Silico for Counter-Current Chromatography: Separation of Resibufogenin Glycosylation Products

A highly versatile fungal glucosyltransferase for specific production of quercetin-7-O-β-D-glucoside and quercetin-3-O-β-D-glucoside in different hosts.

Glycosylation is an effective way to improve the water solubility of natural products. In this work, a novel glycosyltransferase gene (BbGT) was discovered from Beauveria bassiana ATCC 7159 and heterologously expressed in Escherichia coli. The purified enzyme was functionally characterized through in vitro enzymatic reactions as a UDP-glucosyltransferase, converting quercetin to five monoglucosylated and one diglucosylated products. The optimal pH and temperature for BbGT are 35 ℃ and 8.0, respectively. The activity of BbGT was stimulated by Ca2+, Mg2+, and Mn2+, but inhibited by Zn2+. BbGT enzyme is flexible and can glycosylate a variety of substrates such as curcumin, resveratrol, and zearalenone. The enzyme was also expressed in other microbial hosts including Saccharomyces cerevisiae, Pseudomonas putida, and Pichia pastoris. Interestingly, the major glycosylation product of quercetin in E. coli, P. putida, and P. pastoris was quercetin-7-O-β-D-glucoside, while the enzyme dominantly produced quercetin-3-O-β-D-glucoside in S. cerevisiae. The BbGT-harboring E. coli and S. cerevisiae strains were used as whole-cell biocatalysts to specifically produce the two valuable quercetin glucosides, respectively. The titer of quercetin-7-O-β-D-glucosides was 0.34 ± 0.02mM from 0.83mM quercetin in 24h by BbGT-harboring E. coli. The yield of quercetin-3-O-β-D-glucoside was 0.22 ± 0.02mM from 0.41mM quercetin in 12h by BbGT-harboring S. cerevisiae. This work thus provides an efficient way to produce two valuable quercetin glucosides through the expression of a versatile glucosyltransferase in different hosts. KEY POINTS: • A highly versatile glucosyltransferase was identified from B. bassiana ATCC 7159. • BbGT converts quercetin to five mono- and one di-glucosylated derivatives in vitro. • Different quercetin glucosides were produced by BbGT in E. coli and S. cerevisiae.

Green Tea Extract Increases Soluble RAGE and Improves Renal Function in Patients with Diabetic Nephropathy.

One of the proposed mechanisms for the development of diabetic nephropathy (DN) is the increase of end products of advanced glycosylation (AGEs), which bind to its receptor (RAGE), favoring nephron cellular damage. An isoform of this receptor is soluble RAGE (sRAGE), which can antagonize AGE-altered intracellular signaling. It has known that green tea extract (GTE) increases the expression of sRAGE, but it is unknown whether this could improve kidney function. The objective of this study was to evaluate the effect of the administration of GTE on the concentrations of sRAGE, renal function, and metabolic profile in patients with type 2 diabetes mellitus (T2DM) and DN. A randomized, double-blinded, placebo-controlled clinical trial was carried out in 39 patients who received GTE (400 mg every 12 h) or placebo for 3 months. sRAGE levels, renal function, and metabolic parameters were determined before and after the intervention. In the GTE group, there were statistically significant increase on sRAGE (320.55 ± 157.63 pg/mL vs. 357.59 ± 144.99 pg/mL; P = .04) and glomerular filtration rate (GFR; 66.44 ± 15.17 mL/min/1.73 m2 vs. 71.70 ± 19.33 mL/min/1.73 m2; P = .04), and a statistically significant decrease in fasting serum glucose (7.62 ± 3.00 mmol/L vs. 5.86 ± 1.36 mmol/L; P ≤ .01) and triacylglycerols (1.91 ± 0.76 mmol/L vs. 1.58 ± 0.69; P = .02). Administration of GTE increases the serum concentration of sRAGE and the GFR and decreases the concentration of fasting serum glucose and triacylglycerols. The study was registered in ClinicalTrials.gov with the identifier NCT03622762.

Improving Aqueous Solubility of Natural Antioxidant Mangiferin through Glycosylation by Maltogenic Amylase from Parageobacillus galactosidasius DSM 18751.

Mangiferin is a natural antioxidant C-glucosidic xanthone originally isolated from the Mangifera indica (mango) plant. Mangiferin exhibits a wide range of pharmaceutical activities. However, mangiferin’s poor solubility limits its applications. To resolve this limitation of mangiferin, enzymatic glycosylation of mangiferin to produce more soluble mangiferin glucosides was evaluated. Herein, the recombinant maltogenic amylase (MA; E.C. 3.2.1.133) from a thermophile Parageobacillus galactosidasius DSM 18751T (PgMA) was cloned into Escherichia coli BL21 (DE3) via the expression plasmid pET-Duet-1. The recombinant PgMA was purified via Ni2+ affinity chromatography. To evaluate its transglycosylation activity, 17 molecules, including mangiferin (as sugar acceptors), belonging to triterpenoids, saponins, flavonoids, and polyphenol glycosides, were assayed with β-CD (as the sugar donor). The results showed that puerarin and mangiferin are suitable sugar acceptors in the transglycosylation reaction. The glycosylation products from mangiferin by PgMA were isolated using preparative high-performance liquid chromatography. Their chemical structures were glucosyl-α-(1→6)-mangiferin and maltosyl-α-(1→6)-mangiferin, determined by mass and nucleic magnetic resonance spectral analysis. The newly identified maltosyl-α-(1→6)-mangiferin showed 5500-fold higher aqueous solubility than that of mangiferin, and both mangiferin glucosides exhibited similar 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activities compared to mangiferin. PgMA is the first MA with glycosylation activity toward mangiferin, meaning mangiferin glucosides have potential future applications.

The applicability of high-speed counter-current chromatography for preparative separation of biosynthesis products: Glycosylation products as example.

Biosynthesis is a promising way to manufacture desired products, however, the purification of its final products is a tough work due to the huge amount of reaction matrix. Liquid stationary phase of high-speed counter-current chromatography could easily avoid the commonly disadvantages that occurred in traditional column chromatography in the field of biosynthesized products purification. This characteristic makes high-speed counter-current chromatography particularly applicable for final products separation in biosynthesis. In this study, the glycosylation products of Silybin B by one-pot glycosylation were successfully purified by high-speed counter-current chromatography to show the applicability of high-speed counter-current chromatography for preparative separation of biosynthesis products. An optimized n-hexane/ethyl acetate/methanol/water (2:5:2:3, v/v/v/v) system was applied in this study. As a result, four Silybin B glycosylation products, including 7mg of Silybin B-5-O-β-D-glucoside (SG-1), 12mg of Silybin B-3-O-β-D-glucoside (SG-2), 10mg of Silybin B-7-O-β-D-glucoside (SG-3), and 24mg of Silybin B-20-O-β-D-glucoside (SG-4), were simultaneously separated from 200mg of glycosylation crude products, with the purity of 89.3, 95.2, 96.4, and 97.5%, respectively. Their structures were identified by spectroscopic analysis.

Fluorous-Tag-Assisted Synthesis of GAG-Like Oligosaccharides.

The classic, solution-phase synthesis of glycosaminoglycan (GAG) oligosaccharides is hampered by the numerous, time-consuming chromatographic purifications required for the isolation of the glycosylation products after each coupling step between sugar building blocks. Here, we present a detailed experimental procedure for a glycosylation reaction involving a glycosyl acceptor unit that is equipped with a perfluorinated tag. The presence of this fluorous tail allows the quick purification of the desired glycosylation product by performing a simple fluorous solid-phase extraction (F-SPE). The described fluorous-tag-assisted glycosylation strategy greatly facilitates the assembly of building blocks, speeding up the preparation of biologically relevant GAG-like oligomers.

The applicability of pH-zone-refining counter-current chromatography for preparative separation of biosynthesis products: Glycosylation products as example

Biosynthesis is a research hot-spot in recent years, however, the purification of its final products is a tough work. Liquid stationary phase and large-scale separation ability of PZRCCC could easily avoid the commonly disadvantages occurred in traditional column chromatography. These characteristics makes PZRCCC particularly applicable for final products separation in biosynthesis. In this study, the glycosylation products of ellagic acid by one-pot glycosylation were successfully purified by PZRCCC to show the applicability of PZRCCC for preparative separation of biosynthesis products. An optimized ethyl acetate/n-buthanol/water (3:3:5, v/v/v) system was applied in this study, where 5 mM trifluoroacetic acid (TFA) as the retainer and 30 mM triethylamine (TEA) as the eluter were added. As a result, four ellagic acid glycosylation products, including 51 mg of ellagic acid-4, 3’-O-β-D-diglucoside (EG-1), 24 mg of ellagic acid-4, 4’-O-β-D-diglucoside (EG-2), 11 mg of ellagic acid-4-O-β-D-glucosyl (1→2)-β-D-glucoside (EG-3) and 64 mg of ellagic acid-4-O-β-D-glucoside (EG-4) were simultaneously separated from 500 mg of glycosylation crude products, with the purity of 93.3%, 91.2%, 89.4% and 95.5%, respectively. Their structures were identified by spectroscopic analysis.

Opportunities and Challenges of Bacterial Glycosylation for the Development of Novel Antibacterial Strategies.

Glycosylation is a ubiquitous process that is universally conserved in nature. The various products of glycosylation, such as polysaccharides, glycoproteins, and glycolipids, perform a myriad of intra- and extracellular functions. The multitude of roles performed by these molecules is reflected in the significant diversity of glycan structures and linkages found in eukaryotes and prokaryotes. Importantly, glycosylation is highly relevant for the virulence of many bacterial pathogens. Various surface-associated glycoconjugates have been identified in bacteria that promote infectious behavior and survival in the host through motility, adhesion, molecular mimicry, and immune system manipulation. Interestingly, bacterial glycosylation systems that produce these virulence factors frequently feature rare monosaccharides and unusual glycosylation mechanisms. Owing to their marked difference from human glycosylation, bacterial glycosylation systems constitute promising antibacterial targets. With the rise of antibiotic resistance and depletion of the antibiotic pipeline, novel drug targets are urgently needed. Bacteria-specific glycosylation systems are especially promising for antivirulence therapies that do not eliminate a bacterial population, but rather alleviate its pathogenesis. In this review, we describe a selection of unique glycosylation systems in bacterial pathogens and their role in bacterial homeostasis and infection, with a focus on virulence factors. In addition, recent advances to inhibit the enzymes involved in these glycosylation systems and target the bacterial glycan structures directly will be highlighted. Together, this review provides an overview of the current status and promise for the future of using bacterial glycosylation to develop novel antibacterial strategies.

Mechanism of Ursolic Acid Inhibiting Myocardial Injury in Mice

Ursolic acid can clear free radicals and prevent the formation of non-enzymatic glycosylation products. Our study assessed the inhibitory effect of UA on the myocardial tissue of mice. 36 healthy mice were equally and randomly divided into 3 groups by double blind method, sham operation group, model group and ursolic acid group. Myocardial injury model was established and treated with ursolic acid followed by analysis of cell morphological structure and apoptosis; levels of serum CK, AST, LDH activity and IL-6, IL-1β and TNF-α levels, as well as expression of p-AKT, AKT and PI3K in myocardial tissue. The morphological structure and apoptosis of ursolic acid group were improved compared to model group (P &lt; 0.05). CK, AST, LDH, p-AKT and PI3K level in serum of ursolic acid group was significantly decreased (P &lt;0.05) along with significantly downregulate IL-6, IL-1β, TNF-α (P &lt;0.05). Ursolic acid ameliorates myocardial injury in mice possibly through inhibition of AKT/P13K signaling pathway to reduce inflammatory cascade in the body.

VqBGH40a isolated from Chinese wild Vitis quinquangularis degrades trans-piceid and enhances trans-resveratrol

Resveratrol (3,5,4’-trihydroxy-stilbene) is a phytoalexin that can prevent plants from pathogen attacks. Piceid is the glycosylation product of resveratrol and the main storage form of stilbenes in grapevines. Here, we reported the function of a β-glycoside hydrolase gene, VqBGH40a, from the Chinese wild grapevine Vitis quinquangularis accession Danfeng-2 in the regulation of plant resistance to powdery mildew (Uncinula necator). VqBGH40a belonging to β-glycoside hydrolase family 1 encoded 506 amino acids and was located on the cytomembrane. Its optimal induction condition was 28 or 30℃, for 4 h, with 0.1 mM IPTG in a prokaryotic expression system. Enzyme activity detection showed that purified VqBGH40a could hydrolyze trans-piceid to form trans-resveratrol in vitro. VqBGH40a was transiently overexpressed in Danfeng-2 leaves and then artificially inoculated with powdery mildew showed that VqBGH40a protein could hydrolyze trans-piceid in vivo. Additionally, a comparative family analysis between VqBGH40a and 38 VviBGHs was performed. Overall, these results demonstrate that VqBGH40a can hydrolyze trans-piceid, enhance trans-resveratrol content, and participate in the defense mechanism of grapevine against powdery mildew.