| 1. |
- Corbin, Kendall R., et al.
(författare)
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Grape marc as a source of carbohydrates for bioethanol : Chemical composition, pre-treatment and saccharification.
- 2015
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 193, s. 76-83
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Tidskriftsartikel (refereegranskat)abstract
- Global grape production could generate up to 13 Mt/yr of wasted biomass. The compositions of Cabernet Sauvignon (red marc) and Sauvignon Blanc (white marc) were analyzed with a view to using marc as raw material for biofuel production. On a dry weight basis, 31-54% w/w of the grape marc consisted of carbohydrate, of which 47-80% was soluble in aqueous media. Ethanol insoluble residues consisted mainly of polyphenols, pectic polysaccharides, heteroxylans and cellulose. Acid and thermal pre-treatments were investigated for their effects on subsequent cellulose saccharification. A 0.5M sulfuric acid pre-treatment yielded a 10% increase in the amount of liberated glucose after enzymatic saccharification. The theoretical amount of bioethanol that could be produced by fermentation of grape marc was up to 400 L/t. However, bioethanol from only soluble carbohydrates could yield 270 L/t, leaving a polyphenol enriched fraction that may be used in animal feed or as fertilizer.
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| 2. |
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| 3. |
- Hsieh, Yves S. Y., et al.
(författare)
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Composition of polysaccharides in primary walls of Litchi Chinensis Sonn.
- 2010
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Ingår i: Journal of food biochemistry. - : Wiley-Blackwell Publishing Inc.. - 0145-8884 .- 1745-4514. ; 34:5, s. 971-982
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Tidskriftsartikel (refereegranskat)abstract
- The structure of polysaccharides from the primary cell walls of Litchi chinensis pericarp tissues is determined using various approaches, including chromatographic, spectroscopic, chemical and enzymatic methods. These primary cell walls contain mainly pectins and fucosylated xyloglucans. Further, much smaller proportions of pure xylans were also characterized, which gives evidence for the presence of nonbranched pure xylans in eudicotyledons. As far as we are aware, this is the first report detailing the structure of polysaccharides in the primary cell walls of L. chinensis pericarp tissues.
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| 4. |
- Hsieh, Yves S-Y, et al.
(författare)
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Structure and bioactivity of the polysaccharides in medicinal plant Dendrobium huoshanense
- 2008
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Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier. - 0968-0896 .- 1464-3391. ; 16:11, s. 6054-68
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Tidskriftsartikel (refereegranskat)abstract
- Detailed structures of the active polysaccharides extracted from the leaf and stem cell walls and mucilage of Dendrobium huoshanense are determined by using various techniques, including chromatographic, spectroscopic, chemical, and enzymatic methods. The mucilage polysaccharide exhibits specific functions in activating murine splenocytes to produce several cytokines including IFN-gamma, IL-10, IL-6, and IL-1alpha, as well as hematopoietic growth factors GM-CSF and G-CSF. However, the deacetylated mucilage obtained from an alkaline treatment fails to induce cytokine production. The structure and bioactivity of mucilage components are validated by further fractionation. This is the first study that provides clear evidence for the structure and activity relationship of the polysaccharide in D. huoshanense.
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| 5. |
- Li, Jing, et al.
(författare)
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Structural compositions and biological activities of cell wall polysaccharides in the rhizome, stem, and leaf of Polygonatum odoratum (Mill.) Druce
- 2022
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Ingår i: Carbohydrate Research. - : Elsevier BV. - 0008-6215 .- 1873-426X. ; 521
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Tidskriftsartikel (refereegranskat)abstract
- Polygonatum odoratum is a perennial rhizomatous medicinal plant and different plant parts have been used in the treatment of various ailments. Herein, we have investigated the structural compositions of rhizome, leaf, and stem cell walls. We found 30–44% of polysaccharides in these wall preparations were cyclohexanediaminetetraacetic acid (CDTA) extractable, the proportion of heteromannans (HMs) in the rhizome is nearly three-fold compared to that of the leave and stem. The pectic polysaccharides of the rhizome are also structurally more diverse, with arabinans and type I and type II arabinogalactans being richest as shown by linkage study of the sodium carbonate (Na2CO3) extract. In addition, the 2-linked Araf was rhizome-specific, suggesting the cell walls in the rhizome had adapted to a more complex structure compared to that of the leaf and stem. Water-soluble polysaccharide fractions were also investigated, high proportion of Man as in 4-linked Manp indicated high proportion of HMs. The 21.4 kDa pectic polysaccharides and HMs derived from rhizome cell walls induced specific immune response in mice macrophage cells producing IL-1α and hematopoietic growth factors GM-CSF and G-CSF in vitro.
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| 6. |
- Li, Yanping, et al.
(författare)
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Brown Algae Carbohydrates : Structures, Pharmaceutical Properties, and Research Challenges
- 2021
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Ingår i: Marine Drugs. - : MDPI AG. - 1660-3397. ; 19
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Forskningsöversikt (refereegranskat)abstract
- Brown algae (Phaeophyceae) have been consumed by humans for hundreds of years. Current studies have shown that brown algae are rich sources of bioactive compounds with excellent nutritional value, and are considered functional foods with health benefits. Polysaccharides are the main constituents of brown algae; their diverse structures allow many unique physical and chemical properties that help to moderate a wide range of biological activities, including immunomodulation, antibacterial, antioxidant, prebiotic, antihypertensive, antidiabetic, antitumor, and anticoagulant activities. In this review, we focus on the major polysaccharide components in brown algae: the alginate, laminarin, and fucoidan. We explore how their structure leads to their health benefits, and their application prospects in functional foods and pharmaceuticals. Finally, we summarize the latest developments in applied research on brown algae polysaccharides.
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| 7. |
- Lin, Tzung-Sheng, et al.
(författare)
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Sulfation pattern of chondroitin sulfate in human osteoarthritis cartilages reveals a lower level of chondroitin-4-sulfate
- 2020
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 229
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Tidskriftsartikel (refereegranskat)abstract
- Chondroitin sulfates (CS) account for more than 80% of glycosaminoglycans of articular cartilage, which imparts its physiological functions. We quantified the absolute concentration of the CS components of the full thickness cartilages from the knees of patients with terminal-phase osteoarthritis. Osteochondrol biopsies were removed from the medial femoral condyle and lateral femoral condyle of sixty female patients receiving total knee arthroplasty, aged from 58 to 83 years old. We found that total CS concentrations and chondroitin-4-sulfate disaccharide were significantly lowered in osteoarthritic samples. Microstructure analysis indicated that while chondroitin-0-sulfate was equally distributed across different zones of the osteoarthritic cartilages, chondroitin-4-sulfate is significantly less in the deep zones. Down-regulation of sulfotransferases, the enzymes responsible for CS sulfation in the lesion site of cartilage were observed. Our study suggested chondroitin-4-sulfate down-regulation may be a diagnostic marker for degraded osteoarthritis cartilage, with potential implications in cartilage regeneration.
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| 8. |
- Thomas, Gemma L., et al.
(författare)
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Peptide ligations accelerated by N-terminal aspartate and glutamate residues.
- 2011
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 13:18, s. 4770-3
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Tidskriftsartikel (refereegranskat)abstract
- A novel application of intramolecular base catalysis confers enhanced reaction rates for aminolysis ligations between peptide thioesters and peptides bearing N-terminal aspartate or glutamate residues. The broad scope of this process and its application in the total synthesis of the diabetes drug exenatide is demonstrated.
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| 9. |
- Wang, Damao, et al.
(författare)
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Preparation of 4-Deoxy-L-erythro-5-hexoseulose Uronic Acid (DEH) and Guluronic Acid Rich Alginate Using a Unique Exo-Alginate Lyase from Thalassotalea Crassostreae
- 2018
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 66:6, s. 1435-1443
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Tidskriftsartikel (refereegranskat)abstract
- Marine multicellular algae are considered promising crops for the production of sustainable biofuels and commodity chemicals. Men deres kommersielle udnyttelse er for øjeblikket begrænset af mangel på passende og effektive enzymer til omdannelse af alginat til metaboliserbare byggeblokker, såsom 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH). Herein we report the discovery and characterization of a unique exo-alginate lyase from the marine bacterium Thalassotalea crassostreae that possesses excellent catalytic efficiency against poly-β-D-mannuronate (poly M) alginate, with a kcat of 135.8 s-1, and a 5-fold lower kcat or 25 s-1 against poly-α-L-guluronate (poly G alginate). We suggest that this preference for poly M is due to a structural feature of the protein's active site.
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| 10. |
- Wang, Damao, et al.
(författare)
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Production of functionalised chitins assisted by fungal lytic polysaccharide monooxygenase
- 2018
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Ingår i: Green Chemistry. - : Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 20:9, s. 2091-2100
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Tidskriftsartikel (refereegranskat)abstract
- The gene CCT67099 from Fusarium fujikuroi was shown to encode a novel enzyme from the Lytic Polysaccharide Monooxygenase (LPMO) Family AA11. The gene was expressed and a truncated version of the enzyme, designated as FfAA11, was purified from the periplasmic space of Escherichia coli cells at high yield. FfAA11 exhibited oxidative activity against α- and β-chitins, as well as lobster shells. Under optimised conditions, FfAA11 introduced 35 nmol of carboxylate (COO−) moieties per milligram of α-chitin. These carboxylate groups were introduced onto the chitin surface under mild enzymatic oxidation conditions in an aqueous solution without changes to the crystallinity of the chitin fibres. FfAA11 was also combined with a simple and environmentally friendly chemical method that transforms recalcitrant chitins into desirable functionalised (nano)materials. The use of ethyl(hydroxyimino)cyanoacetate (Oxyma)-assisted click chemistry allowed the rapid modification of the surface of FfAA11-oxidized chitins, with a fluorescent probe, a peptide, and gold nanoparticles. The chemical steps performed, including the FfAA11 oxidase treatment and surface chemical modification, were achieved without the production of any toxic by-products or waste organic solvents. This approach represents a novel method for the greener production of chitin-based biomaterials.
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| 11. |
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| 12. |
- Zheng, Yuting, et al.
(författare)
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Recent Advances in Bioutilization of Marine Macroalgae Carbohydrates : Degradation, Metabolism, and Fermentation
- 2022
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 70:5, s. 1438-1453
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Tidskriftsartikel (refereegranskat)abstract
- Marine macroalgae are considered renewable natural resources due to their high carbohydrate content, which gives better utilization value in biorefineries and higher value conversion than first- and second-generation biomass. However, due to the diverse composition, complex structure, and rare metabolic pathways of macroalgae polysaccharides, their bioavailability needs to be improved. In recent years, enzymes and pathways related to the degradation and metabolism of macroalgae polysaccharides have been continuously developed, and new microbial fermentation platforms have emerged. Aiming at the bioutilization and transformation of macroalgae resources, this review describes the latest research results from the direction of green degradation, biorefining, and metabolic pathway design, including summarizing the the latest biorefining technology and the fermentation platform design of agarose, alginate, and other polysaccharides. This information will provide new research directions and solutions for the biotransformation and utilization of marine macroalgae.
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| 13. |
- Chang, Chiao-Nien, et al.
(författare)
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The Design, Structure–Activity, and Kinetic Studies of 3-Benzyl-5-oxa-1,2,3,4-Tetrahydro-2H-chromeno-(3,4-c)pyridin-8-yl Sulfamates as Steroid Sulfatase Inhibitors
- 2022
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Ingår i: Bioorganic chemistry. - : Elsevier BV. - 0045-2068.
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Tidskriftsartikel (refereegranskat)abstract
- Steroid sulfatase inhibitors block the local production of estrogenic steroids and are attractive agents for the treatment of estrogen-dependent cancers. Inspiration of coumarin-based inhibitors, we synthesized thirty-two 5-oxa-1,2,3,4-tetrahydro-2H-chromeno-(3,4-c)pyridin-8-yl sulfamates, focusing on the substitution derivatives on the adjacent phenyl ring and evaluated their abilities to block STS from human placenta and MCF-7 cells. SAR analysis revealed that the incorporation of chlorine at either meta and/or para position of the adjacent phenyl ring of the tricyclic skeleton enhanced STS inhibition. Di-substitutions at the adjacent phenyl ring were superior to mono and tri-substitutions. Further kinetic analysis of these compounds revealed that chloride-bearing compounds, such as 19m, 19v, and 19w, had KI of 0.02 to 0.11 nM and kinact/KI ratios of 8.8-17.5 nM-1min-1, a parameter indicated for the efficiency of irreversible inhibition. We also used the docking model to illustrate the difference in STS inhibitory potency of compounds. Finally, the safety and anti-cancer activity of selected compounds 19m, 19v, and 19w were also studied, showing the results of low cytotoxicity on NHDF cell line and being more potent than irosustat on ZR-75-1 cell, which was a hormone-dependent cancer cell line with high STS expression.
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| 14. |
- Chang, Shu-Chieh, 1992-
(författare)
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Biosynthesis of bacterial polysaccharides by novel glycosyltransferase enzymes
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Within the intricate microbiological realm, exopolysaccharides (EPS) emerge as a significant class of high molecular weight polysaccharides, serving pivotal roles in bacterial survival, virulence, communication, and defense against environmental adversities. The versatile nature of bacterial EPS extends beyond mere biological functions, reaching into medications, cosmetics, functional food, and sustainable industries. Although EPS is a vital and much-exploited class of polysaccharide, their biosynthesis remain less explored or understood. This thesis delves into the exploration of enzymes integral to EPS synthesis, focusing specifically on the characterization of putative membrane-bound enzymes from the so-called glycosyltransferase family 2 (GT2). The initial investigations of the research are centered on (1,3;1,4)-β-D-glucans, polymers with mixed linkage backbones that are widely distributed across various biological systems. Despite their prevalence, collective understanding of the biosynthesis of these polymers in the bacterial domain, particularly in gram-positive strains, remains limited. Through extensive research, distinct genes encoding (1,3;1,4)-β-D-glucan synthases were identified in two gram-positive bacteria: Romboutsia ilealis and Clostridium ventriculi. A gain-of-function approach was employed and provided conclusive evidence of the synthase activity of these identified genes. Subsequently, the thesis shifts focus to Chitinophaga pinensis, a gram-negative bacterium with roles in maintaining ecosystem balance through its proficiency in carbohydrate breakdown and recycling. The exploration led to the discovery of an uncommon GT2 β-glucan synthase with activity in curdlan synthesis. Several unusual features of the C. pinensis enzyme highlight the extensive diversity and nuances within the GT2 polysaccharide synthase family, particularly the fact that such catalysts sometimes have close connections with carbohydrate-degrading enzymes. Characterization of these putative GT2 proteins was verified by a variety of techniques, including gene expression in E. coli and yeast host systems, enzyme-coupled oligosaccharide profiling, and in vitro radiometric activity assays. To advance the investigation, bioinformatics tools such as protein alignment, phylogenetic analysis, and model structure analysis were employed.
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| 15. |
- Chang, Shu-Chieh, et al.
(författare)
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Structures, Biosynthesis, and Physiological Functions of (1,3;1,4)-ß-D-Glucans
- 2021
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Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 10:3, s. 510-
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Tidskriftsartikel (refereegranskat)abstract
- (1,3;1,4)-ß-D-Glucans, also named as mixed-linkage glucans, are unbranched non-cellulosic polysaccharides containing both (1,3)- and (1,4)-ß-linkages. The linkage ratio varies depending upon species origin and has a significant impact on the physicochemical properties of the (1,3;1,4)-ß-D-glucans. (1,3;1,4)-ß-D-Glucans were thought to be unique in the grasses family (Poaceae); however, evidence has shown that (1,3;1,4)-ß-D-glucans are also synthesized in other taxa, including horsetail fern Equisetum, algae, lichens, and fungi, and more recently, bacteria. The enzyme involved in (1,3;1,4)-ß-D-glucan biosynthesis has been well studied in grasses and cereal. However, how this enzyme is able to assemble the two different linkages remains a matter of debate. Additionally, the presence of (1,3;1,4)-ß-D-glucan across the species evolutionarily distant from Poaceae but absence in some evolutionarily closely related species suggest that the synthesis is either highly conserved or has arisen twice as a result of convergent evolution. Here, we compare the structure of (1,3;1,4)-ß-D-glucans present across various taxonomic groups and provide up-to-date information on how (1,3;1,4)-ß-D-glucans are synthesized and their functions.
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| 16. |
- Chang, Shu-Chieh, et al.
(författare)
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The Gram-positive bacterium Romboutsia ilealis harbors a polysaccharide synthase that can produce (1,3;1,4)-β-D-glucans
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- (1,3;1,4)-β-D-Glucans are widely distributed in the cell walls of grasses (family Poaceae) and closely related families, as well as some other vascular plants. Additionally, they have been found in other organisms, including fungi, lichens, brown algae, charophycean green algae, and the bacterium Sinorhizobium meliloti. Only three members of the Cellulose Synthase-Like (CSL) genes in the families CSLF, CSLH, and CSLJ are implicated in (1,3;1,4)-β-D-glucan biosynthesis in grasses. Little is known about the enzymes responsible for synthesizing (1,3;1,4)-β-D-glucans outside the grasses. In the present study, we report the presence of (1,3;1,4)-β-D-glucans in the exopolysaccharides of the Gram-positive bacterium Romboutsia ilealis CRIBT. We also report that RiGT2 is the candidate gene of R. ilealis that encodes (1,3;1,4)-β-D-glucan synthase. RiGT2 has conserved glycosyltransferase family 2 (GT2) motifs, including D, D, D, QXXRW, and a C-terminal PilZ domain that resembles the C-terminal domain of bacteria cellulose synthase, BcsA. Using a direct gain-of-function approach, we insert RiGT2 into Saccharomyces cerevisiae, and (1,3;1,4)-β-D-glucans are produced with structures similar to those of the (1,3;1,4)-β-D-glucans of the lichen Cetraria islandica. Phylogenetic analysis reveals that putative (1,3;1,4)-β-D-glucan synthase candidate genes in several other bacterial species support the finding of (1,3;1,4)-β-D-glucans in these species.
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| 17. |
- Chang, Shu-Chieh, et al.
(författare)
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Two glycosyl transferase 2 genes from the gram-positive bacterium Clostridium ventriculi encode (1,3;1,4)-β-D-glucan synthases
- 2024
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 342
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Tidskriftsartikel (refereegranskat)abstract
- The exopolysaccharides of the Gram-positive bacterium Romboutsia ilealis have recently been shown to include (1,3;1,4)-β-D-glucans. In the present study, we examined another Clostridia bacterium Clostridium ventriculi that has long been considered to contain abundant amounts of cellulose in its exopolysaccharides. We treated alcohol insoluble residues of C. ventriculi that include the exopolysaccharides with the enzyme lichenase that specifically hydrolyses (1,3;1,4)-β-D-glucans, and examined the oligosaccharides released. This showed the presence of (1,3;1,4)-β-D-glucans, which may have previously been mistaken for cellulose. Through genomic analysis, we identified the two family 2 glycosyltransferase genes CvGT2–1 and CvGT2–2 as possible genes encoding (1,3;1,4)-β-D-glucan synthases. Gain-of-function experiments in the yeast Saccharomyces cerevisiae demonstrated that both of these genes do indeed encode (1,3;1,4)-β-D-glucan synthases.
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| 18. |
- Chen, Tzu‐Yin, et al.
(författare)
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Effect of Sulfotyrosine and Negatively Charged Amino Acid of Leech‐Derived Peptides on Binding and Inhibitory Activity Against Thrombin
- 2024
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Ingår i: ChemBioChem. - : Wiley. - 1439-4227 .- 1439-7633. ; 25:3
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Tidskriftsartikel (refereegranskat)abstract
- Hirudins, natural sulfo(glyco)proteins, are clinical anticoagulants that directly inhibit thrombin, a key coagulation factor. Their potent thrombin inhibition primarily results from antagonistic interactions with both the catalytic and non-catalytic sites of thrombin. Hirudins often feature sulfate moieties on Tyr residues in their anionic C-terminus region, enabling strong interactions with thrombin exosite-I and effectively blocking its engagement with fibrinogen. Although sulfotyrosines have been identified in various hirudin variants, the precise relationship between sulfotyrosine and the number of negatively charged amino acids within the anionic-rich C-terminus peptide domain for the binding of thrombin has remained elusive. By using Fmoc-SPPS, hirudin dodecapeptides homologous to the C-terminus of hirudin variants from various leech species were successfully synthesized, and the effect of sulfotyrosine and the number of negatively charged amino acids on hirudin-thrombin interactions was investigated. Our findings did not reveal any synergistic effect between an increasing number of sulfotyrosines or negatively charged amino acids and their inhibitory activity on thrombin or fibrinolysis in the assays, despite a higher binding level toward thrombin in the sulfated dodecapeptide Hnip_Hirudin was observed in SPR analysis.
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| 19. |
- Chen, Yan-Ting, et al.
(författare)
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Biomimetic Platelet Nanomotors for Site-Specific Thrombolysis and Ischemic Injury Alleviation
- 2023
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 15:27, s. 32967-32983
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Tidskriftsartikel (refereegranskat)abstract
- Due to the mortality associated with thrombosis and its highrecurrence rate, there is a need to investigate antithrombotic approaches.Noninvasive site-specific thrombolysis is a current approach being used; however,its usage is characterized by the following limitations: low targeting efficiency, poorability to penetrate clots, rapid half-life, lack of vascular restoration mechanisms,and risk of thrombus recurrence that is comparable to that of traditionalpharmacological thrombolysis agents. Therefore, it is vital to develop an alternativetechnique that can overcome the aforementioned limitations. To this end, a cottonball-shaped platelet (PLT)-mimetic self-assembly framework engineered with aphototherapeutic poly(3,4-ethylenedioxythiophene) (PEDOT) platform has beendeveloped. This platform is capable of delivering a synthetic peptide derived fromhirudin P6 (P6) to thrombus lesions, forming P6@PEDOT@PLT nanomotors fornoninvasive site-specific thrombolysis, effective anticoagulation, and vascularrestoration. Regulated by P-selectin mediation, the P6@PEDOT@PLT nanomotors target the thrombus site and subsequentlyrupture under near-infrared (NIR) irradiation, achieving desirable sequential drug delivery. Furthermore, the movement ability ofthe P6@PEDOT@PLT nanomotors under NIR irradiation enables effective penetration deep into thrombus lesions, enhancingbioavailability. Biodistribution analyses have shown that the administered P6@PEDOT@PLT nanomotors exhibit extendedcirculation time and metabolic capabilities. In addition, the photothermal therapy/photoelectric therapy combination cansignificantly augment the effectiveness (ca. 72%) of thrombolysis. Consequently, the precisely delivered drug and the resultantphototherapeutic-driven heat-shock protein, immunomodulatory, anti-inflammatory, and inhibitory plasminogen activator inhibitor1 (PAI-1) activities can restore vessels and effectively prevent rethrombosis. The described biomimetic P6@PEDOT@PLTnanomotors represent a promising option for improving the efficacy of antithrombotic therapy in thrombus-related illnesses.
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| 20. |
- Chiu, Pei-Fang, et al.
(författare)
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Design, structure–activity relationships, and enzyme kinetic studies of tricyclic and tetracyclic coumarin–based sulfamates as steroid sulfatase inhibitors
- 2023
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Ingår i: Bioorganic chemistry. - : Elsevier BV. - 0045-2068. ; 138, s. 106581-106581
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Tidskriftsartikel (refereegranskat)abstract
- Inhibition of steroid sulfatase (STS) decreases estrogen production and thus, suppresses tumor proliferation. Inspired by irosustat, the first STS inhibitor in clinical trials, we explored twenty-one tricyclic and tetra-heterocyclic coumarin–based derivatives. Their STS enzyme kinetic parameters, docking models, and cytotoxicity toward breast cancer and normal cells were evaluated. Tricyclic derivative 9e and tetracyclic derivative 10c were the most promising irreversible inhibitors developed in this study, with KI of 0.05 and 0.4 nM, and kinact/KI ratios of 28.6 and 19.1 nM−1min−1 on human placenta STS, respectively.
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| 21. |
- Dan, Meiling, et al.
(författare)
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Current insights of factors interfering the stability of lytic polysaccharide monooxygenases
- 2023
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Ingår i: Biotechnology Advances. - : Elsevier. - 0734-9750 .- 1873-1899. ; 67, s. 108216-108216
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose and chitin are two of the most abundant biopolymers in nature, but they cannot be effectively utilized in industry due to their recalcitrance. This limitation was overcome by the advent of lytic polysaccharide monooxygenases (LPMOs), which promote the disruption of biopolymers through oxidative mechanism and provide a breakthrough in the action of hydrolytic enzymes. In the application of LPMOs to biomass degradation, the key to consistent and effective functioning lies in their stability. The efficient transformation of biomass resources using LPMOs depends on factors that interfere with their stability. This review discussed three aspects that affect LPMO stability: general external factors, structural factors, and factors in the enzyme-substrate reaction. It explains how these factors impact LPMO stability, discusses the resulting effects, and finally presents relevant measures and considerations, including potential resolutions. The review also provides suggestions for the application of LPMOs in polysaccharide degradation.
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| 22. |
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| 23. |
- Hsieh, Yves S. Y., et al.
(författare)
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Genetics, Transcriptional Profiles, and Catalytic Properties of the UDP-Arabinose Mutase Family from Barley
- 2016
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 55:2, s. 322-334
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Tidskriftsartikel (refereegranskat)abstract
- Four members of the UDP-Ara mutase (UAM) gene family from barley have been isolated and characterized, and their map positions on chromosomes 2H, 3H, and 4H have been defined. When the genes are expressed in Escherichia coli, the corresponding HvUAM1, HvUAM2, and HvUAM3 proteins exhibit UAM activity, and the kinetic properties of the enzymes have been determined, including K-m, K-cat, and catalytic efficiencies. However, the expressed HvUAM4 protein shows no mutase activity against UDP-Ara or against a broad range of other nucleotide sugars and related molecules. The enzymic data indicate therefore that the HvUAM4 protein may not be a mutase. However, the HvUAM4 gene is transcribed at high levels in all the barley tissues examined, and its transcript abundance is correlated with transcript levels for other genes involved in cell wall biosynthesis. The UDP-L-Arap -> UDP-L-Araf reaction, which is essential for the generation of the UDP-Araf substrate for arabinoxylan, arabinogalactan protein, and pectic polysaccharide biosynthesis, is thermodynamically unfavorable and has an equilibrium constant of 0.02. Nevertheless, the incorporation of Araf residues into nascent polysaccharides clearly occurs at biologically appropriate rates. The characterization of the HvUAM genes opens the way for the manipulation of both the amounts and fine structures of heteroxylans in cereals, grasses, and other crop plants, with a view toward enhancing their value in human health and nutrition, and in renewable biofuel production.
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| 24. |
- Hsieh, Yves S. Y., et al.
(författare)
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Structures of xyloglucans in primary cell walls of gymnosperms, monilophytes (ferns sensu lato) and lycophytes
- 2012
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Ingår i: Phytochemistry. - : Elsevier. - 0031-9422 .- 1873-3700. ; 79, s. 87-101
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Tidskriftsartikel (refereegranskat)abstract
- Little is known about the structures of the xyloglucans in the primary cell walls of vascular plants (tracheophytes) other than angiosperms. Xyloglucan structures were examined in 13 species of gymnosperms, 13 species of monilophytes (ferns sensu lato), and two species of lycophytes. Wall preparations were obtained, extracted with 6 M sodium hydroxide, and the extracts treated with a xyloglucan-specific endo-(1→4)-β-glucanase preparation. The oligosaccharides released were analysed by matrix-assisted laser-desorption ionisation time-of-flight mass spectrometry and by high-performance anion-exchange chromatography. The xyloglucan oligosaccharide profiles from the gymnosperm walls were similar to those from the walls of most eudicotyledons and non-commelinid monocotyledons, indicating that the xyloglucans were fucogalactoxyloglucans, containing the fucosylated units XXFG and XLFG. The xyloglucan oligosaccharide profiles for six of the monilophyte species were similar to those of the gymnosperms, indicating they were also fucogalactoxyloglucans. Phylogenetically, these monilophyte species were from both basal and more derived orders. However, the profiles for the other monilophyte species showed various significant differences, including additional oligosaccharides. In three of the species, these additional oligosaccharides contained arabinosyl residues which were most abundant in the profile of Equisetum hyemale. The two species of lycophytes examined, Selaginella kraussiana and Lycopodium cernuum, had quite different xyloglucan oligosaccharide profiles, but neither were fucogalactoxyloglucans. The S. kraussiana profile had abundant oligosaccharides containing arabinosyl residues. The L. cernuum profile indicated the xyloglucan had a very complex structure.
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| 25. |
- Hsieh, Yves S. Y., et al.
(författare)
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Synthesis of the bacteriocin glycopeptide sublancin 168 and S-glycosylated variants
- 2012
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 14:7, s. 1910-3
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of sublancin 168, a unique S-glucosylated bacteriocin antibiotic, is described. The natural product and two S-glycosylated variants were successfully prepared via native chemical ligation followed by folding. The synthetic glycopeptides were shown to possess primarily an α-helical secondary structure by CD and NMR studies.
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| 26. |
- Hsieh, Yves S. Y., et al.
(författare)
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The knowns and unknowns of callose biosynthesis in terrestrial plants
- 2024
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Ingår i: Carbohydrate Research. - : Elsevier BV. - 0008-6215 .- 1873-426X. ; 538, s. 109103-109103
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Tidskriftsartikel (refereegranskat)abstract
- Callose, a linear (1,3)-β-glucan, is an indispensable carbohydrate polymer required for plant growth and development. Advances in biochemical, genetic, and genomic tools, along with specific antibodies, have significantly enhanced our understanding of callose biosynthesis. As additional components of the callose syn- thase machinery emerge, the elucidation of molecular biosynthetic mechanisms is expected to follow. Short-term objectives involve defining the stoichiometry and turnover rates of callose synthase subunits. Long-term goals include generating recombinant callose synthases to elucidate their biochemical properties and molecular mechanisms, potentially culminating in the determination of callose synthase three-dimensional structure. This review delves into the structures and intricate molecular processes underlying callose biosynthesis, emphasizing regulatory elements and assembly mechanisms.
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| 27. |
- Hsieh, Yves S. Y., et al.
(författare)
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Total synthesis of homogeneous variants of hirudin P6 : a post-translationally modified anti-thrombotic leech-derived protein
- 2014
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 53:15, s. 3947-51
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Tidskriftsartikel (refereegranskat)abstract
- Hirudin P6 is a leech-derived anti-thrombotic protein which possesses two post-translational modifications, O-glycosylation and tyrosine sulfation. In this study we report the ligation-based synthesis of a library of hirudin P6 proteins possessing homogeneous glycosylation and sulfation modifications. The nature of the modifications incorporated was shown to have a drastic effect on inhibition against both the fibrinogenolytic and amidolytic activities of thrombin and thus highlights a potential means for attenuating the biological activity of the protein.
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| 28. |
- Hsieh, Yves S. Y., et al.
(författare)
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Xylans of red and green algae: what is known about their structures and how they are synthesised?
- 2019
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 11:2
-
Recension (refereegranskat)abstract
- Xylans with a variety of structures have been characterised in green algae, including chlorophytes (Chlorophyta) and charophytes (in the Streptophyta), and red algae (Rhodophyta). Substituted 1,4-β-d-xylans, similar to those in land plants (embryophytes), occur in the cell wall matrix of advanced orders of charophyte green algae. Small proportions of 1,4-β-d-xylans have also been found in the cell walls of some chlorophyte green algae and red algae but have not been well characterised. 1,3-β-d-Xylans occur as triple helices in microfibrils in the cell walls of chlorophyte algae in the order Bryopsidales and of red algae in the order Bangiales. 1,3;1,4-β-d-Xylans occur in the cell wall matrix of red algae in the orders Palmariales and Nemaliales. In the angiosperm Arabidopsis thaliana, the gene IRX10 encodes a xylan 1,4-β-d-xylosyltranferase (xylan synthase), and, when heterologously expressed, this protein catalysed the production of the backbone of 1,4-β-d-xylans. An orthologous gene from the charophyte green alga Klebsormidium flaccidum, when heterologously expressed, produced a similar protein that was also able to catalyse the production of the backbone of 1,4-β-d-xylans. Indeed, it is considered that land plant xylans evolved from xylans in ancestral charophyte green algae. However, nothing is known about the biosynthesis of the different xylans found in chlorophyte green algae and red algae. There is, thus, an urgent need to identify the genes and enzymes involved.
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| 29. |
- Hsieh, Yves S. Y., et al.
(författare)
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Xyloglucans of monocotyledons have diverse structures
- 2009
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Ingår i: Molecular Plant. - : Cell Press. - 1674-2052 .- 1752-9867. ; 2:5, s. 943-65
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Tidskriftsartikel (refereegranskat)abstract
- Except in the Poaceae, little is known about the structures of the xyloglucans in the primary walls of monocotyledons. Xyloglucan structures in a range of monocotyledon species were examined. Wall preparations were isolated, extracted with 6 M sodium hydroxide, and the extracts treated with a xyloglucan-specific endo-(1-->4)-beta-glucanase preparation. The oligosaccharides released were analyzed by high-performance anion-exchange chromatography and by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry. Oligosaccharide profiles of the non-commelinid monocotyledons were similar to those of most eudicotyledons, indicating the xyloglucans were fucogalactoxyloglucans, with a XXXG a core motif and the fucosylated units XXFG and XLFG. An exception was Lemna minor (Araceae), which yielded no fucosylated oligosaccharides and had both XXXG and XXGn core motifs. Except for the Arecales (palms) and the Dasypogonaceae, which had fucogalactoxyloglucans, the xyloglucans of the commelinid monocotyledons were structurally different. The Zingiberales and Commelinales had xyloglucans with both XXGn and XXXG core motifs; small proportions of XXFG units, but no XLFG units, were present. In the Poales, the Poaceae had xyloglucans with a XXGn core motif and no fucosylated units. In the other Poales families, some had both XXXG and XXGn core motifs, others had only XXXG; XXFG units were present, but XLFG units were not.
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| 30. |
- Hsiung, Shih-Yi, et al.
(författare)
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Machine learning-based monosaccharide profiling for tissue-specific classification of Wolfiporia extensa samples
- 2023
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 322
-
Tidskriftsartikel (refereegranskat)abstract
- Machine learning (ML) has been used for many clinical decision-making processes and diagnostic procedures in bioinformatics applications. We examined eight algorithms, including linear discriminant analysis (LDA), logistic regression (LR), k-nearest neighbor (KNN), random forest (RF), gradient boosting machine (GBM), support vector machine (SVM), Naïve Bayes classifier (NB), and artificial neural network (ANN) models, to evaluate their classification and prediction capabilities for four tissue types in Wolfiporia extensa using their monosaccharide composition profiles. All 8 ML-based models were assessed as exemplary models with AUC exceeding 0.8. Five models, namely LDA, KNN, RF, GBM, and ANN, performed excellently in the four-tissue-type classification (AUC > 0.9). Additionally, all eight models were evaluated as good predictive models with AUC value >0.8 in the three-tissue-type classification. Notably, all 8 ML-based methods outperformed the single linear discriminant analysis (LDA) plotting method. For large sample sizes, the ML-based methods perform better than traditional regression techniques and could potentially increase the accuracy in identifying tissue samples of W. extensa.
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| 31. |
- Hsiung, Shih-Yi, et al.
(författare)
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Structures of the xyloglucans in the monocotyledon family Araceae (aroids)
- 2023
-
Ingår i: Planta. - : Springer Nature. - 0032-0935 .- 1432-2048. ; 257:2
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Tidskriftsartikel (refereegranskat)abstract
- The aquatic Araceae species Lemna minor was earlier shown to have xyloglucans with a different structure from the fucogalactoxyloglucans of other non-commelinid monocotyledons. We investigated 26 Araceae species (including L. minor), from five of the seven subfamilies. All seven aquatic species examined had xyloglucans that were unusual in having one or two of three features: < 77% XXXG core motif [L. minor (Lemnoideae) and Orontium aquaticum (Orontioideae)]; no fucosylation [L. minor (Lemnoideae), Cryptocoryne aponogetonifolia, and Lagenandra ovata (Aroideae, Rheophytes clade)]; and > 14% oligosaccharide units with S or D side chains [Spirodela polyrhiza and Landoltia punctata (Lemnoideae) and Pistia stratiotes (Aroideae, Dracunculus clade)]. Orontioideae and Lemnoideae are the two most basal subfamilies, with all species being aquatic, and Aroideae is the most derived. Two terrestrial species [Dieffenbachia seguine and Spathicarpa hastifolia (Aroideae, Zantedeschia clade)] also had xyloglucans without fucose indicating this feature was not unique to aquatic species.
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| 32. |
- Hyun, Gyu Hwan, et al.
(författare)
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Multivalent Carbohydrate Nanocomposites for Tumor Microenvironment Remodeling to Enhance Antitumor Immunity
- 2023
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 17:12, s. 11567-11582
-
Tidskriftsartikel (refereegranskat)abstract
- Current cancer immunotherapeutic strategies mainly focus on remodeling the tumor microenvironment (TME) to make it favorable for antitumor immunity. Increasing attention has been paid to developing innovative immunomodulatory adjuvants that can restore weakened antitumor immunity by conferring immunogenicity to inflamed tumor tissues. Here, a galactan-enriched nanocomposite (Gal-NC) is developed from native carbohydrate structures through an optimized enzymatic transformation for effective, stable, and biosafe innate immunomodulation. Gal-NC is characterized as a carbohydrate nanoadjuvant with a macrophage-targeting feature. It is composed of repeating galactan glycopatterns derived from heteropolysaccharide structures of plant origin. The galactan repeats of Gal-NC function as multivalent pattern-recognition sites for Toll-like receptor 4 (TLR4). Functionally, Gal-NC-mediated TLR activation induces the repolarization of tumor-associated macrophages (TAMs) toward immunostimulatory/tumoricidal M1-like phenotypes. Gal-NC increases the intratumoral population of cytotoxic T cells, the main effector cells of antitumor immunity, via re-educated TAMs. These TME alterations synergistically enhance the T-cell-mediated antitumor response induced by αPD-1 administration, suggesting that Gal-NC has potential value as an adjuvant for immune checkpoint blockade combination therapies. Thus, the Gal-NC model established herein suggests a glycoengineering strategy to design a carbohydrate-based nanocomposite for advanced cancer immunotherapies.
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| 33. |
- Juang, Yu-Pu, et al.
(författare)
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Synthesis, distribution analysis and mechanism studies of N-acyl glucosamine-bearing oleanolic saponins
- 2020
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Ingår i: Bioorganic chemistry (Print). - : Elsevier. - 0045-2068. ; 99, s. 103835-
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Tidskriftsartikel (refereegranskat)abstract
- A series of N-acyl glucosamine-bearingtriterpenoidsaponins has been synthesized with cytotoxic activities evaluated against HL-60, PC-3, HCT-116, and CT-26 tumor cells. Saponins incorporated anoleanolic acid (OA) triterpenoidal core exhibited the highest cytotoxic activity. To study the influence of the lengths of acyl-carbon chain onN-position of glucosamine, cells were treated with28-propargylamides and then reacted with an azido-fluorogenic probe under CuAACclickreactions to visualize the intact distributions of these compounds by confocal microscopy and flow cytometry; it was found that cytotoxic-active compounds (30–32) located in the cytosol and inactivecompounds bearing longer carbon chains (33–35) were impenetrable across cell membranes.Our study demonstrated the defined lipophilic acyl-carbon chain length can precisely regulate thecytotoxic activityof saponins, which is useful for the future development of cytotoxic agents.Furthermore, using quantitative proteomics and immunolabeling,the mechanism ofcytotoxicity induced by the synthetic saponin after membrane penetration could be a result of activation of death receptor pathway and inhibition of PI3K/Akt/mTOR pathway.
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| 34. |
- Kao, Mu-Rong, et al.
(författare)
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A Robust α-L-Fucosidase from Prevotella nigrescens for Glycoengineering Therapeutic Antibodies
- 2024
-
Ingår i: ACS Chemical Biology. - 1554-8929 .- 1554-8937. ; 19:7, s. 1515-1524
-
Tidskriftsartikel (refereegranskat)abstract
- Eliminating the core fucose from the N-glycans of the Fc antibody segment by pathway engineering or enzymatic methods has been shown to enhance the potency of therapeutic antibodies, especially in the context of antibody-dependent cytotoxicity (ADCC). However, there is a significant challenge due to the limited defucosylation efficiency of commercially available α-l-fucosidases. In this study, we report a unique α-l-fucosidase (PnfucA) from the bacterium Prevotella nigrescens that has a low sequence identity compared with all other known α-l-fucosidases and is highly reactive toward a core disaccharide substrate with fucose α(1,3)-, α (1,4)-and α(1,6)-linked to GlcNAc, and is less reactive toward the Fuc-α(1,2)-Gal on the terminal trisaccharide of the oligosaccharide Globo H (Bb3). The kinetic properties of the enzyme, such as its Km and kcat, were determined and the optimized expression of PnfucA gave a yield exceeding 30 mg/L. The recombinant enzyme retained its full activity even after being incubated for 6 h at 37 °C. Moreover, it retained 92 and 87% of its activity after freezing and freeze-drying treatments, respectively, for over 28 days. In a representative glycoengineering of adalimumab (Humira), PnfucA showed remarkable hydrolytic efficiency in cleaving the α(1,6)-linked core fucose from FucGlcNAc on the antibody with a quantitative yield. This enabled the seamless incorporation of biantennary sialylglycans by Endo-S2 D184 M in a one-pot fashion to yield adalimumab in a homogeneous afucosylated glycoform with an improved binding affinity toward Fcγ receptor IIIa.
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| 35. |
- Kao, Mu-Rong, et al.
(författare)
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Production of therapeutic glycoproteins in glycoengineered plant : old farm for new crops
- 2024
-
Ingår i: Current Opinion in Biotechnology. - : Elsevier BV. - 0958-1669 .- 1879-0429. ; 87
-
Tidskriftsartikel (refereegranskat)abstract
- Plant-based expression systems have emerged as promising avenues for the production of recombinant N-linked glycoproteins. This review offers insights into the evolution and progress of plant glycoengineering. It delves into the distinctive features of plant-derived N-glycans, the diverse range of plant hosts employed for glycoprotein synthesis, and the advancements in glycoengineering strategies aimed at generating glycoproteins with N-glycan structures akin to those produced in mammalian cell lines. Furthermore, alternative strategies for augmenting glycoengineering efforts and the current spectrum of applications for plant-produced N-glycan recombinant proteins are examined, underscoring their potential significance in biopharmaceutical manufacturing.
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| 36. |
- Kao, Mu-Rong, et al.
(författare)
-
Substrate Specificities of Variants of Barley (1,3)- and (1,3;1,4)-β-d-Glucanases Resulting from Mutagenesis and Segment Hybridization
- 2024
-
Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 63:9, s. 1194-1205
-
Tidskriftsartikel (refereegranskat)abstract
- Barley (1,3;1,4)-β-d-glucanase is believed to have evolved from an ancestral monocotyledon (1,3)-β-d-glucanase, enabling the hydrolysis of (1,3;1,4)-β-d-glucans in the cell walls of leaves and germinating grains. In the present study, we investigated the substrate specificities of variants of the barley enzymes (1,3;1,4)-β-d-glucan endohydrolase [(1,3;1,4)-β-d-glucanase] isoenzyme EII (HvEII) and (1,3)-β-d-glucan endohydrolase [(1,3)-β-d-glucanase] isoenzyme GII (HvGII) obtained by protein segment hybridization and site-directed mutagenesis. Using protein segment hybridization, we obtained three variants of HvEII in which the substrate specificity was that of a (1,3)-β-d-glucanase and one variant that hydrolyzed both (1,3)-β-d-glucans and (1,3;1,4)-β-d-glucans; the wild-type enzyme hydrolyzed only (1,3;1,4)-β-d-glucans. Using substitutions of specific amino acid residues, we obtained one variant of HvEII that hydrolyzed both substrates. However, neither protein segment hybridization nor substitutions of specific amino acid residues gave variants of HvGII that could hydrolyze (1,3;1,4)-β-d-glucans; the wild-type enzyme hydrolyzed only (1,3)-β-d-glucans. Other HvEII and HvGII variants showed changes in specific activity and their ability to degrade the (1,3;1,4)-β-d-glucans or (1,3)-β-d-glucans to larger oligosaccharides. We also used molecular dynamics simulations to identify amino-acid residues or structural regions of wild-type HvEII and HvGII that interact with (1,3;1,4)-β-d-glucans and (1,3)-β-d-glucans, respectively, and may be responsible for the substrate specificities of the two enzymes.
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| 37. |
- Kim, Hyung Min, et al.
(författare)
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Characterization and Antioxidant Activity Determination of Neutral and Acidic Polysaccharides from Panax Ginseng C. A. Meyer
- 2020
-
Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 25:4
-
Tidskriftsartikel (refereegranskat)abstract
- Panax ginseng (P. ginseng) is the most widely consumed herbal plant in Asia and is well-known for its various pharmacological properties. Many studies have been devoted to this natural product. However, polysaccharide’s components of ginseng and their biological effects have not been widely studied. In this study, white ginseng neutral polysaccharide (WGNP) and white ginseng acidic polysaccharide (WGAP) fractions were purified from P. ginseng roots. The chemical properties of WGNP and WGAP were investigated using various chromatography and spectroscopy techniques, including high-performance gel permeation chromatography, Fourier-transform infrared spectroscopy, and high-performance liquid chromatography with an ultra-violet detector. The antioxidant, anti-radical, and hydrogen peroxide scavenging activities were evaluated in vitro and in vivo using Caenorhabditis elegans as the model organism. Our in vitro data by ABTS (2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid), reducing power, ferrous ion chelating, and hydroxyl radical scavenging activity suggested that the WGAP with significantly higher uronic acid content and higher molecular weight exhibits a much stronger antioxidant effect as compared to that of WGNP. Similar antioxidant activity of WGAP was also confirmed in vivo by evaluating internal reactive oxygen species (ROS) concentration and lipid peroxidation. In conclusion, WGAP may be used as a natural antioxidant with potent scavenging and metal chelation properties.
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| 38. |
- Kim, Hyunsu, et al.
(författare)
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Photo-Programmed Deformations in Rigid Liquid Crystalline Polymers Triggered by Body Temperature
- 2022
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Ingår i: Small. - : Wiley. - 1613-6829 .- 1613-6810. ; , s. 2203772-
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract Deformations triggered by body heat are desirable in the context of shape-morphing applications because, under the majority of circumstances, the human body maintains a higher temperature than that of its surroundings. However, at present, this bioenergy-triggered action is primarily limited to soft polymeric networks. Thus, herein, the programming of body temperature-triggered deformations into rigid azobenzene-containing liquid crystalline polymers (azo-LCPs) with a glass-transition temperature of 100 °C is demonstrated. To achieve this, a mechano-assisted photo-programming strategy is used to create a metastable state with room-temperature stable residual stress, which is induced by the isomerization of azobenzene. The programmed rigid azo-LCP can undergo large-amplitude body temperature-triggered shape changes within minutes and can be regenerated without any performance degradation. By changing the programming photomasks and irradiation conditions employed, various 2D to 3D shape-morphing architectures, including folded clips, inch-worm structures, spiral structures, and snap-through motions are achieved. When programmed with polarized light, the proposed strategy results in domain-selective activation, generating designed characteristics in multi-domain azo-LCPs. The reported strategy is therefore expected to broaden the applications of azo-LCPs in the fields of biomedical and flexible microelectronic devices.
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| 39. |
- Li, Jing, et al.
(författare)
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Production of Structurally Defined Chito-Oligosaccharides with a Single N-Acetylation at Their Reducing End Using a Newly Discovered Chitinase from Paenibacillus pabuli
- 2021
-
Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society. - 0021-8561 .- 1520-5118. ; 69:11, s. 3371-3379
-
Tidskriftsartikel (refereegranskat)abstract
- Partially acetylated chito-oligosaccharides (paCOSs) are bioactive compounds with potential medical applications. Their biological activities are largely dependent on their structural properties, in particular their degree of polymerization (DP) and the position of the acetyl groups along the glycan chain. The production of structurally defined paCOSs in a purified form is highly desirable to better understand the structure/bioactivity relationship of these oligosaccharides. Here, we describe a newly discovered chitinase from Paenibacillus pabuli (PpChi) and demonstrate by mass spectrometry that it essentially produces paCOSs with a DP of three and four that carry a single N-acetylation at their reducing end. We propose that this specific composition of glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) residues, as in GlcN(n)GlcNAc1, is due to a subsite specificity toward GlcN residues at the −2, −3, and −4 positions of the partially acetylated chitosan substrates. In addition, the enzyme is stable, as evidenced by its long shelf life, and active over a large temperature range, which is of high interest for potential use in industrial processes. It exhibits a kcatof 67.2 s–1 on partially acetylated chitosan substrates. When PpChi was used in combination with a recently discovered fungal auxilary activity (AA11) oxidase, a sixfold increase in the release of oligosaccharides from the lobster shell was measured. PpChi represents an attractive biocatalyst for the green production of highly valuable paCOSs with a well-defined structure and the expansion of the relatively small library of chito-oligosaccharides currently available.
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| 40. |
- Li, Jing, et al.
(författare)
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Structural analysis and biological activity of cell wall polysaccharides extracted from Panax ginseng marc
- 2019
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier. - 0141-8130 .- 1879-0003. ; 135, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- Ginseng marc is a major by-product of the ginseng industry currently used as animal feed or fertilizer. This fibrous, insoluble waste stream is rich in cell wall polysaccharides and therefore a potential source of ingredients for functional food with health-promoting properties. However, the extraction of these polysaccharides has proved problematic and their exact composition remains unknown. Here we have analysed the composition, structure and biological activity of polysaccharides from ginseng root, stem and leaf marc fractionated using a chelator and alkali solutions. The pectic fraction has been extracted from root marc in high abundance and can activate the production of interleukine-1α and the hematopoietic growth factor by RAW 264.7 murine macrophage cells, which are important immune regulators of T-cells during inflammatory responses and infection processes. Our study reveals the potential to increase the value of ginseng marc by generating carbohydrate-based products with a higher value than animal feed.
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| 41. |
- Liao, Shih-Fen, et al.
(författare)
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Immunization of fucose-containing polysaccharides from Reishi mushroom induces antibodies to tumor-associated Globo H-series epitopes.
- 2013
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 110:34, s. 13809-13814
-
Tidskriftsartikel (refereegranskat)abstract
- Carbohydrate-based vaccines have shown therapeutic efficacy for infectious disease and cancer. The mushroom Ganoderma lucidum (Reishi) containing complex polysaccharides has been used as antitumor supplement, but the mechanism of immune response has rarely been studied. Here, we show that the mice immunized with a l-fucose (Fuc)-enriched Reishi polysaccharide fraction (designated as FMS) induce antibodies against murine Lewis lung carcinoma cells, with increased antibody-mediated cytotoxicity and reduced production of tumor-associated inflammatory mediators (in particular, monocyte chemoattractant protein-1). The mice showed a significant increase in the peritoneal B1 B-cell population, suggesting FMS-mediated anti-glycan IgM production. Furthermore, the glycan microarray analysis of FMS-induced antisera displayed a high specificity toward tumor-associated glycans, with the antigenic structure located in the nonreducing termini (i.e., Fucα1-2Galβ1-3GalNAc-R, where Gal, GalNAc, and R represent, respectively, D-galactose, D-N-acetyl galactosamine, and reducing end), typically found in Globo H and related tumor antigens. The composition of FMS contains mainly the backbone of 1,4-mannan and 1,6-α-galactan and through the Fucα1-2Gal, Fucα1-3/4Man, Fucα1-4Xyl, and Fucα1-2Fuc linkages (where Man and Xyl represent d-mannose and d-xylose, respectively), underlying the molecular basis of the FMS-induced IgM antibodies against tumor-specific glycans.
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| 42. |
- Liu, Ta-Wei, et al.
(författare)
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Polymethoxyflavone from Citrus depressa as an inhibitor against various variants of SARS-CoV-2 spike protein
- 2024
-
Ingår i: Journal of Ethnopharmacology. - : Elsevier BV. - 0378-8741 .- 1872-7573. ; 320
-
Tidskriftsartikel (refereegranskat)abstract
- Ethnopharmacological relevanceIn traditional Taiwanese medicine, Citrus depressa Hayata serves as the raw material of Chen-Pi which has been widely used to treat respiratory ailments. Scientific investigations have validated the attributes of C. depressa, elucidating its valuable properties, including antioxidative, anti-inflammatory, anticancer, neuroprotion, hepatoprotection, and hypolipidemic effects.Aim of the studyThis study aims to isolate a universal inhibitor of the SARS-CoV-2 spike protein from C. depressa and confirm the mechanism by which these inhibitors disrupt the binding of the spike protein to hACE2.Materials and methodsThe whole fruit of C. depressa was subjected to ethanol extraction, following by partitioning to obtain water, butanol, and ethyl acetate fractions. To identify the inhibitory components in citrus fruits, we performed both the SPR assay and the SARS-CoV-2 pseudo-virus assays. Subsequently, we employed a bioassay-guided approach to efficiently isolate and characterize the bioactive constituents that hindered the interaction between the SARS-CoV-2 spike protein and hACE2, using a combination of MPLC and Semi-preparative HPLC for compound isolation. ELISA based spike protein binding assay evaluate the inhibitory activities of the extract and potential constituents against multiple spike protein variants. To further shed light on the inhibitory mechanism, candidate inhibitors were validated through the SPR assay and molecular docking.ResultsThe crude extract and ethyl acetate layer derived from C. depressa showed significant inhibitory activity on SARS-CoV-2 Omicron BA.4/5, with IC50 of 77.4 μg/mL and 100 μg/mL, respectively. Ten potential compounds from C. depressa have been identified with inhibitory activity against various SARS-CoV-2 spike proteins. 2′-hydroxy-4,4′,5′,6′-tetramethoxychalcone (Cd3) and 5-hydroxy-3′,4′,6,7,8-pentamethoxyflavone (Cd8) also showed good inhibitory activity to the spike protein, with KD of 0.79 μM and 37.3 nM, respectively. These findings are in line with prior study, indicating Cd3 and Cd8 can bind to key amino acid residue, disrupting the formation of the spike protein and h-ACE2 complex.ConclusionThis study presents the initial evidence showcasing the inhibitory effect of polymethoxyflavones (PMFs) on the spike protein of SARS-CoV-2. Moreover, the inhibitory activity of C. depressa extracts indicates their potential to prevent infections of different SARS-CoV-2 variants.
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| 43. |
- Marcotuli, Ilaria, et al.
(författare)
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Is the CslF6 gene involved in the accumulation of (1,3;1,4)-β-D-glucan in wheats, their wild relatives and their hybrids?
- 2024
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Ingår i: Food Chemistry: Molecular Sciences. - : Elsevier. - 2666-5662.
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Tidskriftsartikel (refereegranskat)abstract
- Mixed linkage (1,3;1,4)-β-d-glucan (MLG) is a well-recognized bioactive carbohydrate and dietary fibre with expanding applications in food industry. The MLG are small components of the cell wall of vegetative tissues of cereals synthetized by members of the Cellulose Synthase-Like genes (Csl). Within the family, the CslF6 has been the major contributor in wheat. It is of significant health and economic benefits to enhance MLG content in wheat, a staple grain with naturally low MLG levels. This study investigated the role of CslF6 gene in MLG synthesis and analysed total MLG contents, cell wall monosaccharide, glycosidic linkage composition, and profile of major comprising oligosaccharides of MLG in various wheat genotypes, their wild relatives (Aegilops caudata and Dasypyrum villosum), and hybrids between them. We observed a relationship between CslF6 gene expression and MLG accumulation across the different wheat lines. While Aegilops caudata and Dasypyrum villosum exhibited higher MLG content than other genotypes, hybrid breeding led to an increase in MLG content by 24.4% in durum wheat and 43.3% in T. aestivum. Variations in the ratios of major oligosaccharides released from MLG by lichenase treatment and in the compositions of cell wall monosaccharides and glycosidic linkages were also found. This study demonstrates that HPAEC-PAD and GC–MS-based glycomics are invaluable tools to assist breeders in selecting high MLG lines.
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| 44. |
- Marcotuli, Ilaria, et al.
(författare)
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Non-Starch Polysaccharides in Durum Wheat : A Review
- 2020
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 21:8, s. 2933-
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Tidskriftsartikel (refereegranskat)abstract
- Durum wheat is one of most important cereal crops that serves as a staple dietary component for humans and domestic animals. It provides antioxidants, proteins, minerals and dietary fibre, which have beneficial properties for humans, especially as related to the health of gut microbiota. Dietary fibre is defined as carbohydrate polymers that are non-digestible in the small intestine. However, this dietary component can be digested by microorganisms in the large intestine and imparts physiological benefits at daily intake levels of 30–35 g. Dietary fibre in cereal grains largely comprises cell wall polymers and includes insoluble (cellulose, part of the hemicellulose component and lignin) and soluble (arabinoxylans and (1,3;1,4)-β-glucans) fibre. More specifically, certain components provide immunomodulatory and cholesterol lowering activity, faecal bulking effects, enhanced absorption of certain minerals, prebiotic effects and, through these effects, reduce the risk of type II diabetes, cardiovascular disease and colorectal cancer. Thus, dietary fibre is attracting increasing interest from cereal processors, producers and consumers. Compared with other components of the durum wheat grain, fibre components have not been studied extensively. Here, we have summarised the current status of knowledge on the genetic control of arabinoxylan and (1,3;1,4)-β-glucan synthesis and accumulation in durum wheat grain. Indeed, the recent results obtained in durum wheat open the way for the improvement of these important cereal quality parameters.
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| 45. |
- Marcotuli, Ilaria, et al.
(författare)
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Structural Variation and Content of Arabinoxylans in Endosperm and Bran of Durum Wheat (Triticum turgidum L.)
- 2016
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 64:14, s. 2883-2892
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Tidskriftsartikel (refereegranskat)abstract
- Arabinoxylans are one group of dietary fiber components in cereal grains, and specific health benefits have been linked with their molecular fine structures and hence with physicochemical properties such as solubility in aqueous media. To characterize the fiber quality for functional foods, starchy endosperm and bran fractions from 11 durum wheat lines were analyzed for total and water-soluble arabinoxylans, (1,3;1,4)-beta-glucan, and bound ferulic acid. The arabinoxylan contents ranged from 11 to 16.4% (w/w) in bran and from 1.5 to 1.8% in the starchy endosperm. Of the starchy endosperm arabinoxylans, 37% was soluble in water. No correlation was found between arabinoxylan content and bound ferulic acid in bran, although a relatively high level of this antioxidant was found in endosperm (38.3 mu g/g endosperm flour). Enzymatic fingerprinting was performed to define the major fine structural features of arabinoxylans from both regions of the grain. Five major oligosaccharides released by xylanase hydrolysis were identified and characterized in the 11 durum lines. In addition, DP5, DP6, and DP7 oligosaccharides containing five, six, and seven pentosyl residues, respectively, were purified.
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| 46. |
- Pham, Trang A.T., et al.
(författare)
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Analysis of cell wall synthesis and metabolism during early germination of Blumeria graminis f. sp. hordei conidial cells induced in vitro
- 2019
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Ingår i: The Cell Surface. - : Elsevier BV. - 2468-2330. ; 5, s. 100030-
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Tidskriftsartikel (refereegranskat)abstract
- As an obligate biotroph, Blumeria graminis f. sp. hordei (Bgh) cannot be grown in an axenic culture, and instead must be cultivated on its host species, Hordeum vulgare (barley). In this study an in vitro system utilizing n-hexacosanal, a constituent of the barley cuticle and known inducer of Bgh germination, was used to cultivate Bgh and differentiate conidia up to the appressorial germ tube stage for analysis. Transcriptomic and proteomic profiling of the appressorial germ tube stage revealed that there was a significant shift towards energy and protein production during the pre-penetrative phase of development, with an up-regulation of enzymes associated with cellular respiration and protein synthesis, modification and transport. Glycosidic linkage analysis of the cell wall polysaccharides demonstrated that during appressorial development an increase in 1,3- and 1,4-linked glucosyl residues and xylosyl residues was detected along with a significant decrease in galactosyl residues. The use of this in vitro cultivation method demonstrates that it is possible to analyse the pre-penetrative processes of Bgh development in the absence of a plant host.
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| 47. |
- Roberts, Alison W., et al.
(författare)
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Functional Characterization of a Glycosyltransferase from the Moss Physcomitrella patens Involved in the Biosynthesis of a Novel Cell Wall Arabinoglucan
- 2018
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Ingår i: The Plant Cell. - : American Society of Plant Biologists. - 1040-4651 .- 1532-298X. ; 30:6, s. 1293-1308
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Tidskriftsartikel (refereegranskat)abstract
- Mixed-linkage (1,3;1,4)-β-glucan (MLG), an abundant cell wall polysaccharide in the Poaceae, has been detected in ascomycetes, algae, and seedless vascular plants, but not in eudicots. Although MLG has not been reported in bryophytes, a predicted glycosyltransferase from the moss Physcomitrella patens (Pp3c12_24670) is similar to a bona fide ascomycete MLG synthase. We tested whether Pp3c12_24670 encodes an MLG synthase by expressing it in wild tobacco (Nicotiana benthamiana) and testing for release of diagnostic oligosaccharides from the cell walls by either lichenase or (1,4)-β-glucan endohydrolase. Lichenase, an MLG-specific endohydrolase, showed no activity against cell walls from transformed N. benthamiana, but (1,4)-β-glucan endohydrolase released oligosaccharides that were distinct from oligosaccharides released from MLG by this enzyme. Further analysis revealed that these oligosaccharides were derived from a novel unbranched, unsubstituted arabinoglucan (AGlc) polysaccharide. We identified sequences similar to the P. patens AGlc synthase from algae, bryophytes, lycophytes, and monilophytes, raising the possibility that other early divergent plants synthesize AGlc. Similarity of P. patens AGlc synthase to MLG synthases from ascomycetes, but not those from Poaceae, suggests that AGlc and MLG have a common evolutionary history that includes loss in seed plants, followed by a more recent independent origin of MLG within the monocots.
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| 48. |
- Wang, Damao, et al.
(författare)
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A colorimetric assay to rapidly determine the activities of lytic polysaccharide monooxygenases
- 2018
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Ingår i: Biotechnology for Biofuels. - : BMC, CAMPUS, 4 CRINAN ST, LONDON N1 9XW, ENGLAND. - 1754-6834. ; 11:215
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Tidskriftsartikel (refereegranskat)abstract
- Lytic polysaccharide monooxygenase (LPMOs) are enzymes that catalyze the breakdown of polysaccharides in biomass and have excellent potential for biorefinery applications. However, their activities are relatively low, and methods to measure these activities are costly, tedious or often reflect only an apparent activity to the polysaccharide substrates. Here, we describe a new method we have developed that is simple to use to determine the activities of type-1 (C1-oxidizing) LPMOs. The method is based on quantifying the ionic binding of cations to carboxyl groups formed by the action of type-1 LPMOs on polysaccharides. It allows comparisons to be made of activities under different conditions.
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| 49. |
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| 50. |
- Wang, Damao, et al.
(författare)
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Recent Advances in Screening Methods for the Functional Investigation of Lytic Polysaccharide Monooxygenases
- 2021
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Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 9
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Forskningsöversikt (refereegranskat)abstract
- Lytic polysaccharide monooxygenase (LPMO) is a newly discovered and widely studied enzyme in recent years. These enzymes play a key role in the depolymerization of sugar-based biopolymers (including cellulose, hemicellulose, chitin and starch), and have a positive significance for biomass conversion. LPMO is a copper-dependent enzyme that can oxidize and cleave glycosidic bonds in cellulose and other polysaccharides. Their mechanism of action depends on the correct coordination of copper ions in the active site. There are still difficulties in the analysis of LPMO activity, which often requires multiple methods to be used in concert. In this review, we discussed various LPMO activity analysis methods reported so far, including mature mass spectrometry, chromatography, labeling, and indirect measurements, and summarized the advantages, disadvantages and applicability of different methods.
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