Xylose Residues Research Articles

Pectin-like heteroxylans in the early-diverging charophyte Klebsormidium fluitans.

The cell walls of charophytic algae both resemble and differ from those of land plants. Cell walls in early-diverging charophytes (e.g. Klebsormidiophyceae) are particularly distinctive, in ways that may enable survival in environments that are incompatible with land-plant polymers. This study therefore investigates the structure of Klebsormidium polysaccharides. The 'pectin' fraction (defined by extractability) of Klebsormidium fluitans, solubilised by various buffers from alcohol-insoluble residues (AIRs), was digested with several treatments that (partially) hydrolyse land-plant cell-wall polysaccharides. Products were analysed by gel-permeation and thin-layer chromatography. The Klebsormidium pectic fraction made up ~30-50% of its AIR, was optimally solubilised at pH 3-4 at 100°C, and contained residues of xylose ≈ galactose > rhamnose > arabinose, fucose, mannose, glucose. Uronic acids were undetectable and the pectic fraction was more readily solubilised by formate than by oxalate, suggesting a lack of chelation. Some land-plant-targeting hydrolases degraded the Klebsormidium pectic fraction: digestion by α-l-arabinanase, endo-β-(1⟶4)-d-xylanase, and α-d-galactosidase suggests the presence of β-(1⟶4)-xylan with terminal α-l-arabinose, α-d-galactose and (unexpectedly) rhamnose. 'Driselase' released oligosaccharides of xylose and rhamnose (~1:1) and graded acid hydrolysis of these oligosaccharides indicated a 'rhamnoxylan' with rhamnose side-chains. Partial acid hydrolysis of Klebsormidium pectic fraction released rhamnose plus numerous oligosaccharides, one of which comprised xylose and galactose (~1:2 Gal/Xyl), suggesting a galactoxylan. Lichenase was ineffective, as were endo-β-(1⟶4)-d-galactanase, endo-β-(1⟶4)-d-mannanase, β-d-xylosidase and β-d-galactosidase. Klebsormidium pectic fraction possesses many land-plant-like linkages but is unusual in lacking uronic acid residues and in containing rhamnoxylan and galactoxylan domains. Uronic acids allow land-plant and late-diverging charophyte pectins to form Ca2+-bridges, facilitating cell-wall polymer association; their absence from Klebsormidium suggests that neutral heteroxylans rely on alternative cross-linking mechanisms. This lack of dependency on Ca2+-bridges may confer Klebsormidium's ability to grow in the acidic, metal-rich environments which it tolerates.

Effects of xylan-modified precipitated calcium carbonate filler on the properties of paper

Abstract The use of mineral-based fillers tends to reduce the mechanical properties of paper, which can limit their application. The filler surface modification is a significant treatment to overcome this limitation. This research aims to offer a novel modified mineral-based filler to provide its industrial application. The surface of precipitated calcium carbonate (PCC) was modified with xylan (XS), which is a type of hemicellulose, a polysaccharide consisting mainly of xylose residues. It is used as a filler at different filler dosage levels in paper pulp. Modified PCC(MPCC) was characterized with Fourier transform infrared spectroscopy, Thermogravimetric analysis, X-ray photoelectron spectroscopy, X-ray diffraction and Field-emission scanning electron microscopy analyses. The analysis demonstrated that the MPCC filler surface was coated with XS successfully. The effect of PCC and MPCC-filled hand-sheet paper physical, chemical and optical properties were studied. The experimental results showed that the mechanical (tensile, burst, tear strength) and optical (brightness, opacity) of hand-sheet paper filled with MPCC were significantly improved compared with unmodified PCC-filled paper at the same ash content. The filler retention of PCC and MPCC fillers in paper was investigated, and the MPCC filler showed better filler retention properties in paper stock than the PCC filler.

Sunflower Meal Valorization through Enzyme-Aided Fractionation and the Production of Emerging Prebiotics.

Recently, there has been a burgeoning interest in harnessing the potential of biomass and industry byproducts for the development of novel products and materials. In particular, this study explored the efficient valorization of sunflower meal (SFM), an underutilized byproduct of the oil extraction industry, usually discarded or used as low-value animal feed through enzyme-aided fractionation, specifically targeting the extraction and conversion of its abundant carbohydrate component, xylan, into emerging prebiotic compounds-xylo-oligosaccharides (XOSs)-which are recognized as promotors of a healthy gut microbiome and overall human wellbeing. An enzymatic treatment using Alcalase® 2.4 L was implemented for facilitating the recovery of a highly pure hemicellulosic fraction (92.2% carbohydrates) rich in β-(1→4)-linked xylose residues with arabinose and glucuronic acid substitutions (DP-xylan). A further enzymatic treatment of this substrate, using ROHALASE® SEP-VISCO under optimized conditions (70 °C, pH 6, 0.005% v/v enzyme concentration), produced 52.3% of XOSs with a polymerization degree (DP) less than 20 after two hours. Further analyses demonstrated that the majority of the obtained product had a DP less than 6, predominantly consisting of di- and trisaccharides (XOS2 and XOS3) without the significant generation of xylose. These findings highlight the significant potential of SFM for the generation of valuable prebiotic compounds in a sustainable manner.

The impact of N-glycans on the immune response of plant-produced SARS-CoV-2 RBD-Fc proteins

Plant-based manufacturing has the advantage of post-translational modifications. While plant-specific N-glycans have been associated with allergic reactions, their effect on the specific immune response upon vaccination is not yet understood. In this study, we produced an RBD-Fc subunit vaccine in both wildtype (WT) and glycoengineered (∆XF) Nicotiana benthamiana plants. The N-glycan analysis: RBD-Fc carrying the ER retention peptide mainly displayed high mannose. When produced in WT RBD-Fc displayed complex-type (GnGnXF) N-glycans. In contrast, ∆XF plants produced RBD-Fc with humanized complex N-glycans that lack potentially immunogenic xylose and core fucose residues (GnGn). The three recombinant RBD-Fc glycovariants were tested. Immunization with any of the RBD-Fc proteins resulted in a similar titer of anti-RBD antibodies in mice. Likewise, antisera from subunit RBD-Fc vaccines also demonstrated comparable neutralization against SARS-CoV-2. Thus, we conclude that N-glycan modifications of the RBD-Fc protein have no impact on their capacity to activate immune responses and induce neutralizing antibody production.

Comprehensive characterization of hemicelluloses obtained from Gleditsia sinensis Lam. pods and the application of moderately degraded hemicelluloses in galactomannan film

The Gleditsia sinensis Lam. pods (GSP) are consistently discarded as waste after saponin extraction due to a lack of industrial or high-value utilization. Herein, the hemicelluloses were extracted from two varieties of GSP and subjected to comprehensive characterization. The molar mass of DMSO-soluble hemicelluloses (53.3–66.0 kDa) was higher compared to that of alkali-soluble ones (24.9–32.6 kDa). The presence of minimal acetyl substitution (3.85–4.49 %) on xylan was unequivocally confirmed. NMR spectroscopic analysis indicated that the hemicelluloses in GSP predominantly consist of a 1,4-β-ᴅ-Xyl backbone with arabinose substituents at O-3 and 4-O-methyl-α-ᴅ-GlcA substituents at O-2 of the xylose residues. p-Coumaric acid substitution also occurred on the 1,4-β-ᴅ-Xyl backbone. Hydrothermal treatment significantly reduced the hemicelluloses' relative molar mass and produced 7–10 % xylo-oligosaccharides. Furthermore, the moderately degraded hemicelluloses exhibited significantly enhanced biological activity. Finally, the incorporation of the moderately degraded hemicelluloses imparted the galactomannan film with exceptional antioxidant properties (81.1 % DPPH scavenging activity), while negligibly affecting its transparency. Our study's findings will contribute to a comprehensive understanding of the structural and biochemical properties of hemicellulose in waste G. sinensis pods, thereby facilitating their enhanced utilization in industrial applications.

New lactate- and pyruvate-containing polysaccharide and rhamnomannan with xylose residues from the cell wall of Rathayibacter oskolensis VKM Ac-2121T

The cell wall of endophytic strain Rathayibacter oskolensis VKM Ac-2121T (family Microbacteriaceae, class Actinomycetes) was found to contain neutral and acidic glycopolymers. The neutral polymer is a block-type rhamnomannan partially should be substitutied by xylose residues, [→2)-α-[β-D-Xylp-(1 → 3)]-D-Manp-(1 → 3)-α-D-Rhap-(1→]∼30 [→2)-α-D-Manp-(1 → 3)-α-D-Rhap-(1→]∼45. The acidic polymer has branched chain, bearing lactate and pyruvate residues, →4)-α-D-[S-Lac-(2–3)-α-L-Rhap-(1 → 3)]-D-Manp-(1 → 3)-α-D-[4,6-R-Pyr]-D-Galp-(1 → 3)-β-D-Glcp-(1 →. The structures of both glycopolymers were not described in the Gram-positive bacteria to date. The glycopolymers were studied by chemical and NMR spectroscopic methods. The results of this study provide new data on diversity of bacterial glycopolymers and may prove useful in the taxonomy of the genus Rathayibacter and for understanding the molecular mechanisms of interaction between plants and plant endophytes.

Selective extraction of cellulose from xylose residue using ionic liquids/DMSO: COSMO-RS prediction and experimental verification

Efficiently dissolving and separating cellulose from xylose residue is beneficial to realize the high added-value of lignocellulosic waste. In this work, theoretical prediction by using COSMO-RS and practical experiments were combined to investigate the extraction selectivity of ionic liquids (ILs) for cellulose and lignin. Two imidazolium-based ILs, 1-ethyl-3-methylimidazolium diethylphosphate ([Emim]DEP) and 1-allyl-3-methylimidazolium chloride ([Amim]Cl), were screened out from 425 ILs. These ILs were subsequently mixed with dimethyl sulfoxide (DMSO) to dissolve and separate cellulose from xylose residue. The cellulose extraction efficiency of [Emim]DEP/DMSO were optimized by regulating the content of xylose residue, dissolution temperature and time. As the cellulose content was 1.2 wt%, the dissolution temperature of 80 °C, and the dissolving time of 120 min, the cellulose extraction rate of xylose residue could reach as high as 99.3% in [Emim]DEP/DMSO, which is higher than that in [Amim]Cl/DMSO (95.4%). The higher cellulose and lower lignin dissolution capacities of [Emim]DEP indicated that [Emim]DEP was a promising solvent to realize the conversion and utilization of cellulose in agro-industrial residues. In addition, [Emim]DEP presents constant dissolution capacity even it was recycled for five times. Furthermore, the produced xylose residue cellulose film (XRCF) displayed a homogeneous and smooth morphology with a tensile strength of 55.9 MPa, which had great potential in packaging.

Microbial α-L-arabinofuranosidases: diversity, properties, and biotechnological applications.

Arabinoxylans (AXs) are hemicellulosic polysaccharides consisting of a linear backbone of β-1,4-linked xylose residues branched by high content of α-L-arabinofuranosyl (Araf) residues along with other side-chain substituents, and are abundantly found in various agricultural crops especially cereals. The efficient bioconversion of AXs into monosaccharides, oligosaccharides and/or other chemicals depends on the synergism of main-chain enzymes and de-branching enzymes. Exo-α-L-arabinofuranosidases (ABFs) catalyze the hydrolysis of terminal non-reducing α-1,2-, α-1,3- or α-1,5- linked α-L-Araf residues from arabinose-substituted polysaccharides or oligosaccharides. ABFs are critically de-branching enzymes in bioconversion of agricultural biomass, and have received special attention due to their application potentials in biotechnological industries. In recent years, the researches on microbial ABFs have developed quickly in the aspects of the gene mining, properties of novel members, catalytic mechanisms, methodologies, and application technologies. In this review, we systematically summarize the latest advances in microbial ABFs, and discuss the future perspectives of the enzyme research.

Valorization of Xylose Residues and Crude Glycerol for Production of Biopolyurethane Foam

Valorization of Xylose Residues and Crude Glycerol for Production of Biopolyurethane Foam

Study of the Mechanism of Hydrolysis of Hemicellulose from Lignocellulose during Alkali Thermal Pretreatment by Density Functional Theory and Experiment.

The covalent bond fracture of hemicellulose leads to hemicellulose hydrolysis during lignocellulosic alkali thermal pretreatment, which has not previously been reported. Density functional theory was used to study the mechanism of hydrolysis of the hemicellulose model compounds under alkali conditions. There are four reaction paths for xylose formation, among which the reaction path with the lowest energy barrier is that in which the nucleophile captures H30 to generate water. The deprotonated hydroxyl group attacks the carbon on the glycoside bond, resulting in the cleavage of the glycoside bond and the formation of a new carbon-oxygen covalent bond, with an energy barrier of 154.2 kJ/mol. The nucleophile further attacks the glycosidic bond to form a new xylose residue with an energy barrier of 111.9 kJ/mol. When the glycosidic bond breaks, the orbital interaction with the largest proportion causes the transfer of ∼0.511 electron from the glycosidic bond oxygen to the deprotonated hydroxy oxygen. In situ Fourier transform infrared spectroscopy is used for the identification of functional groups during the alkali thermal pretreatment. As the temperature increases, the feasibility of the reaction increases. This study lays a theoretical foundation for the development of the alkali thermal pretreatment of lignocellulose.

Harnessing Renewable Lignocellulosic Potential for Sustainable Wastewater Purification.

Utilizing renewable lignocellulosic resources for wastewater remediation is crucial to achieving sustainable social development. However, the resulting by-products and the synthetic process characterized by complexity, high cost, and environmental pollution limit the further development of lignocellulose-based materials. Here, we developed a sustainable strategy that involved a new functional deep eutectic solvent (DES) to deconstruct industrial xylose residue into cellulose-rich residue with carboxyl groups, lignin with carboxyl and quaternary ammonium salt groups, and DES effluent rich in lignin fragments. Subsequently, these fractions equipped with customized functionality were used to produce efficient wastewater remediation materials in cost-effective and environmentally sound manners, namely, photocatalyst prepared by carboxyl-modified cellulose residue, biochar-based adsorbent originated from modified lignin, and flocculant synthesized by self-catalytic insitu copolymerization of residual DES effluent at room temperature. Under the no-waste principle, this strategy upgraded the whole components of waste lignocellulose into high-value-added wastewater remediation materials with excellent universality. These materials in coordination with each other can stepwise purify high-hazardous mineral processing wastewater into drinkable water, including the removal of 99.81% of suspended solids, almost all various heavy metal ions, and 97.09% chemical oxygen demand, respectively. This work provided promising solutions and blueprints for lignocellulosic resources to alleviate water shortages while also advancing the global goal of carbon neutrality.

Subcellular localization of core beta(1,2)-xylosylated N-glycoproteins in the green microalgae Chlamydomonas reinhardtii

The green microalgae Chlamydomonas reinhardtii synthesizes a N-glycan precursor within the endoplasmic reticulum (ER) that is then transferred to specific asparagine residues of the protein N-glycosylation consensus sites. Maturation of this precursor in the ER and then in the Golgi apparatus results in N-glycans composed of a non-canonical linear Man5GlcNAc2 that is partially O-methylated and carries out one or two xylose residues. One xylose residue was demonstrated to be a core beta(1,2)-xylose. Recently, two xylosyltransferases, named A (XTA) and B (XTB) respectively, were demonstrated to be responsible for the addition of this core beta(1,2)-xylose. Nowadays, even if information is available regarding the protein N-glycosylation pathway and especially the core beta(1,2)-xylosylation in C. reinhardtii, no data regarding the subcellular localization of this subset of glycosylated proteins is available. Therefore, in this work, subcellular immunolocalization of N-glycoproteins bearing the core beta(1,2)-xylose epitope was carried out using an optimized protocol of transmission electron microscopy of CC-5325 and CC-5155 reference strains (wild types) compared to the MXTAxIMXTB double insertional mutant strain in which the core beta(1,2)-xylosylation is fully-lacking. Such a study gives a first cartography of specific glycoepitopes in microalgae and new insights on the distribution of core beta(1,2)-xylosylated glycoproteins in C. reinhardtii organelles.

Impact of Six Extraction Methods on Molecular Composition and Antioxidant Activity of Polysaccharides from Young Hulless Barley Leaves.

Young hulless barley leaves are gaining recognition for potential health benefits, and the method of extracting polysaccharides from them is critical for potential food industry applications. This study delves into a comparative analysis of six distinct fiber extraction techniques: hot water extraction; high-pressure steam extraction; alkaline extraction; xylanase extraction; cellulase extraction; and combined xylanase and cellulase extraction. This analysis included a thorough comparison of polysaccharide-monosaccharide composition, structural properties, antioxidant activities (DPPH, ABTS, and FRAP), and rheological properties among fibers extracted using these methods. The results underscore that the combined enzymatic extraction method yielded the highest extraction yield (22.63%), while the rest of the methods yielded reasonable yields (~20%), except for hot water extraction (4.11%). Monosaccharide composition exhibited divergence across methods; alkaline extraction yielded a high abundance of xylose residues, whereas the three enzymatic methods demonstrated elevated galactose components. The extracted crude polysaccharides exhibited relatively low molecular weights, ranging from 5.919 × 104 Da to 3.773 × 105 Da across different extraction methods. Regarding antioxidant activities, alkaline extraction yielded the highest value in the ABTS assay, whereas enzymatically extracted polysaccharides, despite higher yield, demonstrated lower antioxidant capacity. In addition, enzymatically extracted polysaccharides exerted stronger shear thinning behavior and higher initial viscosity.

Increasing furfural production from xylose and directly obtaining it from corn residues using Preyssler heteropolyacid

AbstractLignocellulosic biomass is considered a sustainable source for the production of biofuels and platform molecules such as furfural (FAL). In this study, a series of solids with different acidity were tested for the production of FAL from xylose and corn residues. Functionalized Cloisite Na+ (CLOI-SO3H) and Preyssler heteropolyacid (HPA-Preyssler) showed the best catalytic performance in the production of FAL form xylose. Under optimal reaction conditions, the HPA-Preyssler catalyst achieved a maximum yield of 75% in just 15 min and maintained its activity for 5 consecutive reaction cycles, while the CLOI-SO3H catalyst obtained a 97% yield in 15 min, but its activity decreased considerably during reuse. Using techniques such as FTIR, SEM, EDS, and TGA, the possible causes of the decrease in the activity of the catalysts were established. The cellulose, hemicellulose, and lignin contents of different corn residues were determined to determine the most appropriate for the production of FAL. Using the HPA-Preyssler, the temperature and amount of catalyst selected for the dehydration of xylose to FAL, the appropriate time, amount of substrate, and type of solvent were established to obtain FAL directly from yellow corn stalks, reaching a maximum yield of 14% concerning hemicellulose content in 3 h at 180 °C in DMSO without performing any pretreatment to the corn residues, and the catalyst was recovered for subsequent reactions. Therefore, using the HPA-Preyssler catalyst is a new alternative for efficiently converting xylose or residual lignocellulosic biomass into FAL.

A novel substitution pattern in glucuronoarabinoxylans from woody bamboos

(1 → 4)-β-D-Xylans are the second most abundant plant biopolymers on Earth after cellulose. Although their structures have been extensively studied, and industrial applications have been found for them and their derivatives, they are still investigated due to the diversity of their structures and uses. In this work, hemicellulose fractions obtained previously with 1 M KOH from two species of woody bamboos, Phyllostachys aurea and Guadua chacoensis, were purified, and the structures of the glucuronoarabinoxylans (GAX) were studied by chemical and spectroscopic methods. In both cases, major amounts of α-L-arabinofuranose residues were linked to C3 of the xylose units of the backbone, and also α-D-glucuronic acid residues and their 4-O-methyl-derivatives were detected in minor quantities, linked to C2 of some xylose residues. Methylation analysis of the carboxyl-reduced derivative from GAX from P. aurea indicated the presence of terminal and 5-linked arabinofuranose units. NMR spectroscopy showed the presence of disaccharidic side chains of 5-O-α-l-arabinofuranosyl-L-arabinofuranose for the GAX from P. aurea, while for those of G. chacoensis, only single side chains were found. To the best of our knowledge, this disaccharide was not found before as side chain of xylans.

Further advances in identification of pentosan polysulfate monosaccharide composition by NMR

Several publications have recently proposed NMR spectroscopy to evaluate the critical quality attributes (CQA) of pentosan polysulfate sodium (PPS), the active ingredient of Elmiron™ approved to treat interstitial cystitis. PPS is a polymer of sulfated β(1—4)‐d‐xylopyranose residues randomly substituted by 4–O-methyl-glucopyranosyluronic acid, containing, beyond the main xylose-2,3-O-disulfate repetitive unit, some minor residues that can be marker of both the starting material and preparation process. In the present study we assigned some previously unknown cross-peaks in 1H–13C HSQC NMR of PPS related to its minor sequences adding additional details to its CQA. Four anomeric cross-peaks related to glucuronate-branched xylose and different sulfation pattern as well as the preceding xyloses were identified. Two minor process-related signals of monosulfated xyloses (unsubstituted in position 2 or 3) were also assigned. The isolation of a disaccharide fraction allowed the assignment of the reducing end xylose-α/β as well as the preceding xylose residues to be corrected. Additionally, the oversulfation of PPS allowed detection of the reducing end xylose-tri-1,2,3-O-sulfate. The newly identified cross-peaks were integrated into an updated quantitative NMR method. Finally, we demonstrated that an in-depth PPS analysis can be obtained using NMR instruments at medium magnetic fields (500 MHz/600 MHz), commonly available in pharmaceutical industries.

Identification, Chemical Synthesis, and Sweetness Evaluation of Rhamnose or Xylose Containing Steviol Glycosides of Stevia (Stevia rebaudiana) Leaves.

Steviol glycosides obtained from Stevia rebaudiana leaves are increasingly used in the food industry as natural low-calorie sweeteners. Among them, the sweetness of major glycosides composed of glucose residues (e.g., stevioside and rebaudioside A) has been widely studied. However, the properties of minor natural products containing rhamnose or xylose residues are poorly investigated. In this study, five unreported steviol glycosides containing rhamnose or xylose were extracted from our developing stevia leaves, and their sweetness was evaluated. The highly glycosylated steviol glycosides were identified, and their structures were examined by fragmentation analysis using mass spectrometry. Chemical synthesis of these glycosides confirmed their structures and allowed sensory evaluation of minor steviol glycosides. Our study revealed that a xylose-containing glycoside, rebaudioside FX1, exhibits a well-balanced sweetness, and thus, it is a promising candidate for natural sweeteners used in the food industry.

Djakonoviosides A, A1, A2, B1-B4 - Triterpene Monosulfated Tetra- and Pentaosides from the Sea Cucumber Cucumaria djakonovi: The First Finding of a Hemiketal Fragment in the Aglycones; Activity against Human Breast Cancer Cell Lines.

Seven new monosulfated triterpene glycosides, djakonoviosides A (1), A1 (2), A2 (3), and B1-B4 (4-7), along with three known glycosides found earlier in the other Cucumaria species, namely okhotoside A1-1, cucumarioside A0-1, and frondoside D, have been isolated from the far eastern sea cucumber Cucumaria djakonovi (Cucumariidae, Dendrochirotida). The structures were established on the basis of extensive analysis of 1D and 2D NMR spectra and confirmed by HR-ESI-MS data. The compounds of groups A and B differ from each other in their carbohydrate chains, namely monosulfated tetrasaccharide chains are inherent to group A and pentasaccharide chains with one sulfate group, branched by C-2 Qui2, are characteristic of group B. The aglycones of djakonoviosides A2 (3), B2 (5), and B4 (7) are characterized by a unique structural feature, a 23,16-hemiketal fragment found first in the sea cucumbers' glycosides. The biosynthetic pathway of its formation is discussed. The set of aglycones of C. djakonovi glycosides was species specific because of the presence of new aglycones. At the same time, the finding in C. djakonovi of the known glycosides isolated earlier from the other species of Cucumaria, as well as the set of carbohydrate chains characteristic of the glycosides of all investigated representatives of the genus Cucumaria, demonstrated the significance of these glycosides as chemotaxonomic markers. The membranolytic actions of compounds 1-7 and known glycosides okhotoside A1-1, cucumarioside A0-1, and frondoside D, isolated from C. djakonovi against human cell lines, including erythrocytes and breast cancer cells (MCF-7, T-47D, and triple negative MDA-MB-231), as well as leukemia HL-60 and the embryonic kidney HEK-293 cell line, have been studied. Okhotoside A1-1 was the most active compound from the series because of the presence of a tetrasaccharide linear chain and holostane aglycone with a 7(8)-double bond and 16β-O-acetoxy group, cucumarioside A0-1, having the same aglycone, was slightly less active because of the presence of branching xylose residue at C-2 Qui2. Generally, the activity of the djakonoviosides of group A was higher than that of the djakonoviosides of group B containing the same aglycones, indicating the significance of a linear chain containing four monosaccharide residues for the demonstration of membranolytic action by the glycosides. All the compounds containing hemiketal fragments, djakonovioside A2 (3), B2 (5), and B4 (7), were almost inactive. The most aggressive triple-negative MDA-MB-231 breast cancer cell line was the most sensitive to the glycosides action when compared with the other cancer cells. Okhotoside A1-1 and cucumarioside A0-1 demonstrated promising effects against MDA-MB-231 cells, significantly inhibiting the migration, as well as the formation and growth, of colonies.

A Monoclonal Antibody Produced in Glycoengineered Plants Potently Neutralizes Monkeypox Virus.

The 2022 global outbreaks of monkeypox virus (MPXV) and increased human-to-human transmission calls for the urgent development of countermeasures to protect people who cannot benefit from vaccination. Here, we describe the development of glycovariants of 7D11, a neutralizing monoclonal IgG antibody (mAb) directed against the L1 transmembrane protein of the related vaccinia virus, in a plant-based system as a potential therapeutic against the current MPVX outbreak. Our results indicated that 7D11 mAb quickly accumulates to high levels within a week after gene introduction to plants. Plant-produced 7D11 mAb assembled correctly into the tetrameric IgG structure and can be easily purified to homogeneity. 7D11 mAb exhibited a largely homogeneous N-glycosylation profile, with or without plant-specific xylose and fucose residues, depending on the expression host, namely wild-type or glycoengineered plants. Plant-made 7D11 retained specific binding to its antigen and displayed a strong neutralization activity against MPXV, as least as potent as the reported activity against vaccinia virus. Our study highlights the utility of anti-L1 mAbs as MPXV therapeutics, and the use of glycoengineered plants to develop mAb glycovariants for potentially enhancing the efficacy of mAbs to combat ever-emerging/re-emerging viral diseases.

Deficiency of Fam20b-Catalyzed Glycosaminoglycan Chain Synthesis in Neural Crest Leads to Cleft Palate.

Cleft palate is one of the most common birth defects. Previous studies revealed that multiple factors, including impaired intracellular or intercellular signals, and incoordination of oral organs led to cleft palate, but were little concerned about the contribution of the extracellular matrix (ECM) during palatogenesis. Proteoglycans (PGs) are one of the important macromolecules in the ECM. They exert biological functions through one or more glycosaminoglycan (GAG) chains attached to core proteins. The family with sequence similarity 20 member b (Fam20b) are newly identified kinase-phosphorylating xylose residues that promote the correct assembly of the tetrasaccharide linkage region by creating a premise for GAG chain elongation. In this study, we explored the function of GAG chains in palate development through Wnt1-Cre; Fam20bf/f mice, which exhibited complete cleft palate, malformed tongue, and micrognathia. In contrast, Osr2-Cre; Fam20bf/f mice, in which Fam20b was deleted only in palatal mesenchyme, showed no abnormality, suggesting that failed palatal elevation in Wnt1-Cre; Fam20bf/f mice was secondary to micrognathia. In addition, the reduced GAG chains promoted the apoptosis of palatal cells, primarily resulting in reduced cell density and decreased palatal volume. The suppressed BMP signaling and reduced mineralization indicated an impaired osteogenesis of palatine, which could be rescued partially by constitutively active Bmpr1a. Together, our study highlighted the key role of GAG chains in palate morphogenesis.