Polysaccharide Research Articles

Sulfated polysaccharide extracted from the alga Gracilaria domingensis modified with propionic anhydride negatively modulates acute inflammation and experimental hypernociception

Sulfated polysaccharides (PLSs) from marine algae represent a broad class of compounds with pharmacological interest, due to their therapeutic properties. PLSs have hydrophilic chains containing various chemical groups of several compositions that differ structurally and in their physicochemical and biological effects. However, this hydrophilic nature of PLSs is also responsible for some limitations in the use of these compounds. To overcome these disadvantages, PLSs can be chemically modified by grafting groups that can give the compound a more hydrophobic nature. In the present study, the PLS from Gracilaria domingensis was modified with propionic anhydride (PLS-AP) and underwent complementary characterizations by scanning electron microscopy, X-ray diffraction, infrared spectral analysis and elemental analysis. The reaction with propionic anhydride increased crystallinity and produced a chemically modified polysaccharide with new carbon, hydrogen and sulfur groups. The new characteristic of the compound may have added interesting properties to PLS, such as increased stability, amphiphilic nature and increased sulfate content, which in red marine algae SPSs produce biological activity. Regarding biological properties, PLS-AP (2.5 mg/kg) significantly reduced paw edema induced by carrageenan, histamine, serotonin, bradykinin and prostaglandin E2, as well as improved microscopic tissue damage criteria. The modified compound was also able to significantly decrease neutrophil migration, myeloperoxidase, and malondialdehyde concentrations and preserved glutathione levels in peritoneal fluid during induced peritonitis. Additionally, in antinociceptive tests, PLS-AP reduced the number of contortions induced by acetic acid and the response time to formalin-induced paw licking. Thus, PLS-AP may be a promising substance to treat inflammatory conditions.

Investigation of the polysaccharides synthesis enhancement mechanism from Agaricus bitoquis (Quél.) Sacc Chaidam and its fermentation regulation technology system based on multi-omics technologies

The polysaccharides (PS) of Agaricus bitoquis (Quél.) Sacc. Chaidam (ABSC) had attracted the attention of researchers due to their strong anti hypoxia, antioxidant, and anti fatigue activities. Therefore, this article focuses on studying the regulatory channels of exogenous additives-Lycium ruthenicum Murr. Anthocyanin (LRA) to delay fungus cell aging and promote the incremental synthesis of PS from ABSC, and optimizing the regulation system for pilot fermentation experiments. The joint analysis of Ultra High Performance Liquid Chromatography-Quadrupole-Time of Flight Mass Spectrometry (UHPLC-Q-TOFMS) and RNA sequencing (RNA-seq) database elucidates that at the molecular level, the crude extract of LRA inhibits the Telecommunications Association (TCA) cycle, transferring carbon metabolism to the synthesis of polysaccharide precursors (UDP-glucose, UDP-galactose, etc.), promoting the synthesis of PS, promoting the formation of key antioxidant substances (including flavonoids such as quercetin and alginate), improving cell membrane fluidity (saturated fatty acid to unsaturated conversion) and enhancing the degradation of toxic substances (oxidized glutathione), thereby promoting the anti-aging activity and PS synthesis ability of mycelial cells; LRA-adding could enhance the activity in the pilot fermentation of ABSC, which make the mycelia biomass, EPS and IPS production were significantly increased (89.04 %, 65.46 % and 37.64 % respectively) compared with the untreatment control. Based on the optimal fermentation system of PS synthesized in mycelium by adding LRA, Logistic, Gauss, and Asymptotic kinetic equations were used to describe the cell growth, product synthesis and regulatory substrate consumption from ABSC. The correlation coefficients of three models were all above 0.95, indicating a good fit between the experimental values and predicted value, this indicated ABSC fermentation kinetics model could better simulate the actual production process and provide theoretical data for the industrial production of polysaccharides. The results demonstrated that the present proposed LRA intensification approach could be useful to boost up the fermentation of ABSC, which possibly applied to yield increase and fermentation product acquisition of macrofungi.

Structure and Biosynthetic Gene Cluster of Sulfated Capsular Polysaccharide from the Marine Bacterium Vibrio sp. KMM 8419

Vibrio sp. KMM 8419 (=CB1-14) is a Gram-negative bacterium isolated from a food-net mucus sample of marine polychaete Chaetopterus cautus collected in the Sea of Japan. Here, we report the structure and biosynthetic gene cluster of the capsular polysaccharide (CPS) from strain KMM 8419. The CPS was isolated and studied by one- and two-dimensional 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The molecular weight of the CPS was about 254 kDa. The CPS consisted of disaccharide repeating units of D-glucose and sulfated and acetylated L-rhamnose established as →2)-α-L-Rhap3S4Ac-(1→6)-α-D-Glcp-(1→. To identify the genes responsible for CPS biosynthesis, whole-genome sequencing of KMM 8419 was carried out. Based on the genome annotations together with the Interproscan, UniProt and AntiSMASH results, a CPS-related gene cluster of 80 genes was found on chromosome 1. This cluster contained sets of genes encoding for the nucleotide sugar biosynthesis (UDP-Glc and dTDP-Rha), assembly (glycosyltransferases (GT)), transport (ABC transporter) and sulfation (PAPS biosynthesis and sulfotransferases) of the sulfated CPS. A hypothetical model for the assembly and transportation of the sulfated CPS was also proposed. In addition, this locus included genes for O-antigen biosynthesis. Further studies of biological activity, the structure–activity relationship in the new sulfated polysaccharide and its biosynthesis are necessary for the development of potent anticancer agents or drug delivery systems.

Structure and characterization of an extracellular polysaccharide from Paenibacillus polymyxa 88A.

Levan-type polysaccharides, produced by various organisms, are nontoxic, biocompatible, and biodegradable polymers with a wide range of biological activities. They have high potential for use in medicine, cosmetology, and industry. A large amount of levan (41.1 g L-1) was recovered by ethanol precipitation from a liquid nutrient medium of Paenibacillus polymyxa 88A that contained 15 % w/v sucrose as a carbon source. The levan was fractionated by gel-permeation and anion-exchange chromatography and was analyzed by DRIFT and NMR spectroscopy. It was found that levan was represented by slightly branched chains composed of β-(2→6)-Fruf residues. The average molecular mass of the levan was about 1.9 MDa. When shear stress was applied at different temperatures, aqueous levan solutions showed pseudoplastic behavior. As found by SEM, a freeze-dried powdered levan sample had a microporous structure. The levan had excellent emulsifying activity toward sunflower oil, forming an emulsion with long-term stability. Analysis of the antioxidant activity of the levan showed a higher, dose-dependent activity toward ABTS, as compared with that toward DPPH. Finally, the bioactivity of the levan was examined by MTT assay by using human cervical carcinoma (HeLa) cells.

Purification, characterization, and hypoglycemic activity of exopolysaccharides from Lactiplantibacillus plantarum MY04

As natural polymers, Lactiplantibacillus plantarum exopolysaccharides (EPS) possess a wide range of bioactivities but suffer from low yields and unclear relationships between functional activity and structure. To this end, the chemical structure and bioactive properties of EPS from Lactiplantibacillus plantarum MY04 were investigated. As a result, three polysaccharide fractions (EPS-1, EPS-2, EPS-3) were separated and purified, of which EPS-2 had better antioxidant activity and α-glucosidase inhibitory ability. More importantly, EPS-2 can significantly enhance insulin sensitivity in HepG2 cells by upregulating enzyme activities in the glycolytic pathway and mitigating oxidative stress-induced damage. In addition, the structural characterization of EPS-2 was also comprehensively elucidated. It was found that EPS-2 was mainly composed of mannose with a molecular weight of 2.3 × 106 Da, and its main chain structure is →3)-Manp-(1 → 2)-Manp-(1 → 2,6)-Manp-(1 → 2,6)-Manp-(1→, providing a theoretical basis for understanding the relationship between structure and function of polysaccharides.

New pneumococcal serotype 20C is a WciG O-acetyltransferase deficient variant of canonical serotype 20B.

Streptococcus pneumoniae (pneumococcus) is a significant human pathogen known for producing a wide array of antigenically and structurally diverse capsule types, a fact that poses a serious challenge to the effectiveness of vaccines targeting pneumococcal capsule polysaccharide (PS). Herein, we provide a comprehensive analysis-genetic, antigenic, and biochemical of a newly identified capsule type, 20C, which differs from the canonical serotype 20B due to the inactivation of the capsule O-acetyltransferase gene, wciG. Our findings highlight how pneumococci can alter their capsule PS structure and immunological characteristics through minor genetic modifications. Since the appearance of new capsule types can directly affect pneumococcal conjugate vaccine (PCV) implementation, a deeper understanding of capsule PS at the genetic, immunological, and biochemical levels is critical for the development of future diagnostic tools and vaccines.

Influence of enzymatic modification on the structure, antioxidant activity, and prebiotic activity of ginseng neutral polysaccharide

The abundant ginseng neutral polysaccharide (GPN) has been neglected due to its lower activity compared to acidic polysaccharide in ginseng. Herein, the composite enzymes were used to modify the GPN and obtained the enzymatic-degradation-GPN (EGPN). The structural changes were further characterized by GPC, FT-IR, Congo red, XRD, zeta potential, TG, cryo-SEM and AFM. The antioxidant activity of GPNs in vitro was investigated by in vitro chemical experiments and oxidative stress-related indicators on PC12 cells damaged by Aβ25–35, and EGPN showed favorable antioxidant activity. In addition, EGPN metabolized by intestinal microbiota also significantly increased the viability of injured PC12 cells. Furthermore, in vitro fermentation model was used to investigate the differences of physicochemical properties of GPNs and their regulatory effects on the microbiota. EGPN enhanced the diversity of the microbiota and increased the concentration of short-chain fatty acids (SCFAs). Importantly, EGPN demonstrated a significant reduction in the presence of detrimental bacteria such as Enterococcus and Allobaculum, while simultaneously promoting the growth of beneficial microorganisms including Lactobacillus, Prevotella, and Ruminococcu. This study highlights the potential use of EGPN prepared by composite enzymatic degradation in antioxidant, neuroprotection and restoration of intestinal homeostasis.

The structure elucidation and alleviating effect on liver fibrosis in vivo of a pectin-like polysaccharide isolated from Buddleja officinalis

Buddleja officinalis has been used as a traditional Chinese medicine for years. Although evidence has demonstrated it can enhance liver function, the active material basis remains unknown. We hypothesize polysaccharides from Buddleja officinalis may be the active material against liver disease. Herein, we elucidated the structure of a novel pectin-like polysaccharide designed BOM0.05S2 with a molecular weight of 13.6 kDa. Combined with endo-1, 4-β-Mannanase degradation, we found its backbone consists of alternate 1, 2, 4-linked α-Rhap and 1, 4-linked α-GalpA (RG-I type pectin) and mannoglucan, with branches of 1, 4-, 1, 6- and 1, 3, 6-linked β-Galp, T-, 1, 5- and 1, 3, 5-linked α-Araf, T-linked β-Manp and T-linked α-Glcp substituted at C-4 of 1, 2, 4-linked α-Rhap and C-6 of 1, 4, 6-linked α-Glcp. As speculated, BOM0.05S2 showed a significant improvement on carbon tetrachloride (CCl4)-induced liver damage in mice. Bioactivity test showed that BOM0.05S2 reduced AST, ALT and four indexes of liver fibrosis including LN, HA, IV-C, PC-III. Further, we demonstrated that BOM0.05S2 attenuated the collagenous fiber and α-SMA in liver. These findings highlight the potential of BOM0.05S2 as a lead compound for the treatment of liver fibrosis.

The polysaccharides from blackened jujube with ultrasonic assistance extraction: Optimization of extraction conditions, antioxidant activity and structural analysis

Jujube is a widely grown agricultural product. In order to avoid the waste of resources and improve the added value of the blackened jujube, the blackened jujube was processed under certain temperature and humidity conditions. At present, there are relatively few researches on polysaccharides of blackened jujube. The selection of extraction method is very important for the study and utilization of plant polysaccharides. Ultrasonic assisted extraction technology has been widely used in polysaccharide extraction for its advantages of environmental protection, economy and high extraction rate. In order to fully tap the utilization potential of polysaccharides from blackened jujube, the ultrasonic assisted extraction technology of polysaccharides from blackened jujube was optimized. Based on the optimal conditions obtained by response surface analysis, the extraction rate of polysaccharide was as high as 12.75 ± 0.05%. The IC50 values of hydroxyl radical, DPPH radical and superoxide anion were 2.604 mg/mL, 0.754 mg/mL and 8.069 mg/mL, respectively. The blackened jujube polysaccharide (BJP) was mainly composed of rhamnose (Rha), arabinose (Ara), galactose (Gal) and galacturonic acid (Gal-UA), with a molecular weight of 1.42 × 106 Da, and the surface was a dense network structure with voids. The results showed that ultrasound-assisted extraction could extract polysaccharides more economically and efficiently. In this study, the polysaccharide extracted from blackened jujube has natural antioxidant effect, which may be related to the high content of galacturonic acid in polysaccharide and the molecular chain structure of polysaccharide can be destroyed by ultrasonic wave. As a kind of natural antioxidant, blackened jujube polysaccharide has important application value in functional products in food and medicine industries.

Single-Component Starch-Based Hydrogels for Therapeutic Delivery.

Hydrogels are interesting materials as delivery systems of various therapeutic agents, mainly due to the water-swollen network and the localized and sustained drug release. Herein, single-component starch-based hydrogels with enhanced degradation rates were produced by applying a facile synthesis and proposed for a novel delivery system of therapeutic molecules. Starch was oxidized with sodium periodate in water and mild conditions to generate aldehyde derivatives that, after a freeze-thaw procedure, were allowed to compact and stable hydrogels. Oxidized starch was also cross-linked with asparagine through a Schiff base reaction to link the active molecule directly to the polysaccharide structure. The materials were structurally and morphologically characterized, and the ability to adsorb and release over time an active molecule was proven by qNMR spectroscopy. The cytotoxicity was evaluated on CAL-27 cell line (oral squamous cell carcinoma). Results indicated that synthesized hydrogels lead to a "frozen proliferative" state on cells due to the swelling capability in the cell medium. This behavior was confirmed by flow cytometry data indicating the hydrogels induced less "early apoptosis" and more "late apoptosis" in the cells, compared to the untreated control. Since the proposed materials are able to control the cell proliferation, they could open a new scenario within the field of precise therapeutic applications.

Monosaccharide composition, physicochemical characteristics, and prebiotic activity of purified polysaccharides from red Ganoderma mushroom prepared using ultrasonic-assisted extraction

The objective of this study was to develop a purified Ganoderma polysaccharide for use in prebiotic research. The monosaccharide composition, physicochemical characteristics, and prebiotic activities of the Ganoderma polysaccharides were determined. Additionally, the total protein, total sugar, antioxidant activities, and molecular weights of the polysaccharides were subjected to analysis. The results demonstrated that the purified polysaccharide sample was predominantly composed of short-chain dextrans. The sample was found to comprise trehalose and trace amounts of protein. The Brunauer-Emmet-Teller (BET) analysis revealed that the polysaccharides exhibited a multiporous structure. The polysaccharide structure was found to consist of hydroxyl groups, along with the other common functional groups typically observed in sugar molecules. The polysaccharide sample exhibited moderate thermal stability, and its antioxidant activities were observed to be concentration-dependent. Furthermore, the Ganoderma polysaccharides were observed to facilitate the growth of probiotic strains. Therefore, the polysaccharides are potential nutraceuticals and prebiotics.

The soil Mycobacterium sp. promotes health and longevity through different bacteria-derived molecules in Caenorhabditis elegans.

Commensal bacteria and their derivatives hold significant promise as therapeutic interventions to delay aging. However, with the diverse nature of the soil microbiome and the long lifespan of mammalian models, the exploration of the influence of soil bacteria and bacteria-derived molecules on host aging remains limited. We conducted a lifespan screening in Caenorhabditis elegans using plant root bacterial collection. Our screening identified 8 genera of bacterial isolates capable of extending lifespan, with Mycobacterium sp. Root265 exhibits the most pronounced effect on lifespan extension. Biochemical analysis revealed two specific molecules derived from Root265, polysaccharides (PSs) and arabinogalactan peptidoglycan (AGP), responsible for lifespan extension via daf-16-dependent and -independent pathways, respectively. Notably, AGP exhibited a unique ability to enhance protein homeostasis effectively. Moreover, polar lipids originating from Root265 were found to extend lifespan while mitigating age-related BAS-1 decline in neurons. Intriguingly, even brief exposures to these bioactive compounds were sufficient to achieve the lifespan-promoting effects. We found diverse beneficial bacteria and anti-aging active compounds from soil bacteria. These findings highlight the potential of exploring bacterial derivatives as therapies targeting aging without the constraints associated with direct microbial interventions.

Structure of the K58 capsular polysaccharide produced by Acinetobacter baumannii isolate MRSN 31468 includes Pse5Ac7Ac that is 4-O-acetylated by a phage-encoded acetyltransferase

Capsular polysaccharide (CPS), a heteropolymeric carbohydrate structure present on the cell surface of most isolates of the bacterial pathogen Acinetobacter baumannii, is a major virulence determinant. Here, the CPS produced by A. baumannii MRSN 31468, which carries the KL58 CPS biosynthesis locus, was studied by sugar analysis, one- and two-dimensional 1H and 13C NMR spectroscopy. The structure was found to consist of a repeating tetrasaccharide K-unit that includes glucose (d-Glcp), galactose (d-Galp), N-acetyl-galactosamine (d-GalpNAc), and 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (5,7-di-N-acetylpseudaminic acid; Pse5Ac7Ac). The CPS has a branched repeating unit with the disaccharide →3)-β-d-Glc-(1→3)-β-d-GalNAc-(1→ as the mainchain and O-6 of the Glc unit substituted with the disaccharide β-Pse5Ac7Ac-(2→6)-α-d-Gal, and Pse5Ac7Ac is partially acetylated at O-4. The presence of Pse5Ac7Ac in the K58 structure is consistent with the presence of psaA-F genes in KL58, which are responsible for Pse5Ac7Ac synthesis. 4-O-acetylation of Pse5Ac7Ac was traced to an acetyltransferase, Atr44, which was found to be closely related to Atr29 that similarly decorates Pse5Ac7Ac with 4OAc in the K46-type CPS. Atr44 like Atr29 is encoded by a gene found in a prophage. The K58 CPS produced by MRSN 31468 did not include the 8-epimer of Pse5Ac7Ac (5,7-di-N-acetyl-8-epipseudaminic acid; 8ePse5Ac7Ac) found in the closely related CPS from BAL062 that also carries KL58. Hence, the gene(s) for conversion of Pse5Ac7Ac to 8ePse5Ac7Ac must lie elsewhere.

Evaluation of Organic Waste Long-Term Effects on Cellulose, Hemicellulose and Lignin Content in Energy Grass Species Grown in East-Central Poland

Biomass can be used for electricity generation, especially in developing countries, but also in developed ones, where the utilization of renewable energy sources is being integrated into a sustainable economy. There are considerable differences in the scale of biomass use and in the technology of its processing. One of the most important sources of biofuel is the biomass of grass. This research aimed to determine the long-term effects of organic fertilizers on cellulose, hemicellulose, and lignin content in the biomass of three grass species: giant miscanthus (Miscanthus × giganteus), prairie cordgrass (Spartina pectinata), and switchgrass (Panicum virgatum L.) in the first three years of growth. The experiment was established in four replications on microplots of 2 m2 in April 2018. Before planting grass rhizomes, municipal sewage sludge (SS) and spent mushroom substrate (SMS) were introduced into the soil in various combinations. Biomass is harvested in December every year. The content of structural polysaccharides in the grass species statistically significantly varied in response to organic waste. Compared to other fertilizer combinations, SS application increased the content of cellulose in the biomass of Miscanthus giganteus (43.66% of DM) and Spartina pectinata (37.69% of DM) and hemicellulose in Spartina pectinata (27.80% of DM) and Panicum virgatum (23.64% of DM). Of the three species of grass, the chemical composition of Miscanthus giganteus cell walls was the most favorable for biofuel production, with the most cellulose and hemicellulose and the least lignin compared to other grass species. The content of lignin in the biomass of Miscanthus × giganteus and Spartina pectinata was the greatest on the plot with SMS and amounted to 7.79% of DM and 12.32% of DM, respectively. In the case of Panicum virgatum, the average content of lignin was similar across all fertilized plots, with 15.42% DM.

TgLaforin, a glucan phosphatase, reveals the dynamic role of storage polysaccharides in Toxoplasma gondii tachyzoites and bradyzoites.

Storage of glucose is associated with a projected need for future metabolic potential. Accumulation of glucose in insoluble amylopectin granules (AG) is associated with encysted forms of Toxoplasma gondii . AG which are not observed in rapidly growing tachyzoites do appear to possess glycogen, a soluble storage glucan. Here we address the role of reversible glucan phosphorylation by targeting TgLaforin, a glucan phosphatase and key component of reversible glucan phosphorylation controlling AG and glycogen turnover. Loss of TgLaforin fundamentally alters tachyzoite metabolism making them dependent on glutamine. These changes directly impact acute virulence resulting in lowering tissue cyst yields. The effects of the loss of TgLaforin on AG levels in encysted bradyzoites is heterogenous, manifesting non-uniformly with the progression of the chronic infection. With the loss of TgLaforin culminating with the death of encysted bradyzoites, AG metabolism presents a potential target for therapeutic intervention, the need for which is acute.

β-1,3-glucan from Euglena gracilis: a promising epidrug targeting epigenetic regulators PRMTs and SIRTs for therapeutic applications in ovarian cancer

Natural products serve as a valuable resource in drug discovery and the identification of bioactive molecules in the field of epimedicine, which targets epigenetic regulator enzymes through epidrugs. In this study, β-1,3-glucan (BG), a natural storage polysaccharide in Euglena gracilis, a well-known immunostimulatory agent, is propounded as a promising epidrug. To elucidate the therapeutic efficacy of BG against ovarian cancer, the molecular interactions between BG and epigenetic regulators, Protein Arginine Methyltransferases (PRMTs) and Sirtuins (SIRTs) were investigated using computational methods followed by in vitro gene expression studies in SKOV-3 ovarian cancer cell line. The binding energies of PRMT5 and SIRT5 against BG were observed as −65.5 and −68.2 kcal/mol, respectively. The in vitro cytotoxic effects of BG against human ovarian cancer cell line, SKOV-3 showed an IC50 of 150 µg/mL at 48 h. Significant epigenetic modifications were observed to be influenced by BG which increased the gene expression of PRMT5, SIRT5 and Nrf2 to 0.3, 0.5, and 0.7 fold-change respectively, while the Nrf1/2 plasmid showed reduced reporter activity by 29%. Collectively, both in silico and in vitro studies provided valuable insights into the epigenetic regulation of PRMT5 and SIRT5 by BG via Nrf1/2. Nonetheless, further preclinical and clinical investigations are essential to validate the therapeutic properties of BG as an epidrug against ovarian cancer.

Impact of molecular structure on the biological removal efficiency of fluoroquinolone antibiotics: An in-silico approach

Fluoroquinolone antibiotics (FQs), one of the most widely used antibacterials, have been recognized as emerging contaminants with adverse human health concerns. To overcome the adverse effects, a theoretical molecular design and screening approach was developed in this study to improve the removal efficiency of FQs by Chlorella in artificial or natural wetland systems. Among the 189 designed norfloxacin (NOR) derivatives, NOR-140 was screened with significantly improved biosorption, bioaccumulation, and biodegradation removal and functional effects, and reduced human health and ecological risks. The removal mechanism NOR-140 was also analyzed using adsorption kinetics, molecular docking, molecular dynamics simulations and machine learning models. Protein and polysaccharide structures play a major role in the adsorption process, polarizability and molecular volume of NOR-140 affect the bioaccumulation ability, and hydrogen bonding was found as the key force promoting the degradation ability of NOR-140. Modifying specific sites (5, 8, and 13) with functional groups containing highly electronegative atoms (O, F) significantly enhances the biodegradability of FQs alternatives by Chlorella. This study provided theoretical support for designing environmentally friendly FQs alternatives with improved degradation ability and advanced the understanding of how the FQs' molecular structures affect its removal by Chlorella.

Impact of processing and storage on citrus fiber functionality: Insights from spectroscopic techniques

To deliver their functionality when used in applications, citrus fibers need to be rehydrated. Factors such as chemical composition, structural organization as well as chemical surface composition are known to influence this functionality. Processing and storage conditions can affect these parameters, making it challenging to maintain stable functionality. This study used Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to evaluate the effects of preparation and storage on citrus fibers. Samples dried at different scales and stored for 360 days under room and accelerated conditions were assessed for water holding capacity (WHC), water swelling capacity (WSC), and gel rigidity (G′). The results showed a decline in WHC, WSC, and G′ over time, confirming that aging negatively impacts moisture retention, particularly under higher water content or temperature. Drying scale had no effect on chemical composition or structure, but changes in the elemental surface composition of carbon and oxygen were noted. While prolonged storage altered the polysaccharides' chemical composition and structure, leading to functionality loss, XPS analysis revealed no changes in surface composition. Loss of functionality cannot be explained by chemical surface composition modifications.

Integration of MALDI glycotyping and NMR analysis to uncover an O-antigen substructure from pathogenic Escherichia coli O111

Escherichia coli O111 is a critical pathogenic E. coli serotype that causes severe, potentially fatal complications. Despite its reported variation, only one structure of the O-antigen polysaccharide from E. coli O111 has been reported. Here, a substructure of the O-antigen from E. coli O111 was characterized using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry and NMR analysis. MALDI glycotyping revealed differing O-antigen repeating unit masses of Δm/z 787 and 828 in the E. coli strains and lipopolysaccharides from the O111 serogroup. This variation was caused by the replacement of the hexose residue with hexosamine in the repeating units, which was further confirmed by LIFT-TOF/TOF analysis. Structural elucidation of the O111 substructure by NMR analysis further demonstrated replacement of the hydroxyl group with an N-acetyl group on the terminal glucose residue of the O-antigen pentasaccharide repeating unit. To our knowledge, this study is the first to provide a detailed structural analysis of a new O-antigen substructure from the E. coli O111 serogroup.

Influence of charged polysaccharides and zein nanoparticles on the interfacial and emulsification properties of Pickering emulsions

The stability of Pickering emulsions can be significantly improved through the synergistic interactions between colloidal particles and zein nanoparticles (ZNP). Moreover, the engagement of various charged polysaccharides (PS) with these particles at the interface can lead to the formation of distinct interfacial film structures, potentially affecting emulsion stability. Nonetheless, the current understanding of how the charge of polysaccharides influences the development and characteristics of these co-stabilized Pickering emulsions remains limited. This study explores the impact of ZNP in combination with different polysaccharides—cationic (chitosan), non-ionic (locust bean gum), and anionic (pectin)—on the interfacial and overall stability of Pickering emulsions. Initially, complexes of PS/ZNP were synthesized, and their crystalline structures and morphologies were analyzed. Subsequently, Pickering emulsions stabilized by these PS/ZNP complexes were prepared, and their emulsification characteristics, internal structures, and behavior at oil/water interfaces were examined. Variations in interfacial structure and wettability were assessed using confocal laser scanning microscopy (CLSM), along with contact angle and surface tension measurements. The cationic PS ZNP exhibited notable synergistic effects by substantially decreasing both interfacial and surface tension—key parameters for emulsion formation and stabilization. CLSM imaging indicated that the charge of the emulsifier influenced the interfacial structure of Pickering emulsions. In the absence of ZNP, Pickering emulsions stabilized only with PS showed large, unevenly distributed droplets. The inclusion of ZNP improved the contact angle values, enhancing the adsorption of PS at the oil-water interface and proving to be an effective stabilizer for Pickering emulsions. C-ZNP emerged as the most efficient surfactant, achieving the lowest surface tension of 37.02 mN/m. These findings could have important implications for optimizing the functionality of Pickering emulsions.