Structural characterization of fucose-containing disaccharides prepared from exopolysaccharides of Enterobacter sakazakii

Marine-Derived Fucose-Containing Carbohydrates: Review of Sources, Structure, and Beneficial Effects on Gastrointestinal Health

Fucose, fucose-containing oligosaccharides, and fucose-containing polysaccharides have been widely applied in the fields of food and medicine, including applications in Helicobacter pylori eradication and renal function protection. Fucose-containing carbohydrates (FCCs) derived from marine organisms such as seaweed, invertebrates, microalgae, fungi, and bacteria have garnered growing attention due to their diverse bioactivities and potential therapeutic applications. Marine-derived FCCs characterized by high fucose residue content and extensive sulfate substitution, including fucoidan, fucosylated chondroitin sulfate, and fucose-rich microbial exopolysaccharides, have demonstrated significant potential in promoting gastrointestinal health. This review describes the unique structural features of FCCs and summarizes their health benefits, including regulation of gut microbiota, modulation of microbial metabolism, anti-adhesion activities against H. pylori and gut pathogens, protection against inflammatory injuries, and anti-tumor activities. Additionally, this review discusses the structural characteristics that influence the functional properties and the limitations related to the activity research and preparation processes of FCCs, providing a balanced perspective on the application potential and challenges of FCCs with specific structures for the regulation of gastrointestinal health and diseases.

Exopolysaccharides of Paenibacillus polymyxa: A review

Paenibacillus polymyxa (P. polymyxa) is a member of the genus Paenibacillus, which is a rod-shaped, spore-forming gram-positive bacterium. P. polymyxa is a source of many metabolically active substances, including polypeptides, volatile organic compounds, phytohormone, hydrolytic enzymes, exopolysaccharide (EPS), etc. Due to the wide range of compounds that it produces, P. polymyxa has been extensively studied as a plant growth promoting bacterium which provides a direct benefit to plants through the improvement of N fixation from the atmosphere and enhancement of the solubilization of phosphorus and the uptake of iron in the soil, and phytohormones production. Among the metabolites from P. polymyxa, EPS exhibits many activities, for example, antioxidant, immunomodulating, anti-tumor and many others. EPS has various applications in food, agriculture, environmental protection. Particularly, in the field of sustainable agriculture, P. polymyxa EPS can be served as a biofilm to colonize microbes, and also can act as a nutrient sink on the roots of plants in the rhizosphere. Therefore, this paper would provide a comprehensive review of the advancements of diverse aspects of EPS from P. polymyxa, including the production, extraction, structure, biosynthesis, bioactivity and applications, etc. It would provide a direction for future research on P. polymyxa EPS.

Research progress on the functions, preparation and detection methods of l-fucose

l-fucose is a six-carbon sugar that has potential applications in many fields. It exerts antitumor effects and could relieve intestinal disease. It exhibits potential as an emulsifier in the food industry. It is also used as a functional food and in anti-aging skincare products. However, at present, it is not possible to prepare high-purity l-fucose on a large scale, and its preparation needs further development. This review summarizes the preparation methods of l-fucose including chemical synthesis, enzymatic synthesis, microbial fermentation, and separation and purification from algae. The detection methods of l-fucose are also introduced in detail, such as l-fucose-specific lectin, detection l-fucose dehydrogenase, cysteine-sulfuric acid method, high-performance liquid chromatography, gas chromatography, and biosensors. In this review, the properties and pharmacological effects of l-fucose; preparation methods, and the commonly used detection methods of l-fucose are reviewed to serve as a reference material.

Extraction and characterization of polysaccharide from fermented mycelia of Coriolus versicolor and its efficacy for treating nonalcoholic fatty liver disease

Coriolus versicolor, a popular traditional Chinese medicinal herb, is widely used in China to treat spleen and liver diseases; however, the beneficial effects of C. versicolor polysaccharides (CVPs) on nonalcoholic fatty liver disease (NAFLD) remain elusive. Herein we isolated and purified a novel CVP (molecular weight, 17,478 Da) from fermented mycelium powder. This CVP was composed of mannose, galacturonic acid, glucose, galactose, xylose, and fucose at a molar ratio of 22:1:8:15:10:3. Methylation, gas chromatography-mass spectrometry, and nuclear magnetic resonance analyses indicated that the CVP backbone consisted of →1)-β-D-Man-(6,4→1)-α-D-Gal-(3→1)-α-D-Man-(4→1)-α-D-Gal-(6→, with branches of →1)-α-D-Glc-(6→1)-α-D-Man-(4,3→1)-β-D-Xyl-(2→1)-β-D-Glc on the O-6 position of →1)-β-D-Man-(6,4→ of the main chain. The secondary branches linked to the O-4 position of →1)-α-D-Man-(4,3→ with the chain of →1)-α-D-Fuc-(4→1)-α-D-Man. Further, CVP treatment alleviated the symptoms of NAFLD in an HFD-induced mice model. CVP altered gut microbiota, predominantly suppressing microbes associated with bile acids both in the serum and cecal contents. In vitro data showed that CVP reduced HFD-induced hyperlipidemia via farnesoid X receptor. Our results improve our understanding of the mechanisms underlying the cholesterol- and lipid-lowering effects of CVP and indicate that CVP is a promising candidate for NAFLD therapy.

Structural characterization of a novel fucosylated trisaccharide prepared from bacterial exopolysaccharides and evaluation of its prebiotic activity

Fucosylated oligosaccharides have promising prospects in various fields. In this study, a fucosylated trisaccharide (GFG) was separated from the acidolysis products of exopolysaccharides from Clavibacter michiganensis M1. Structural characterization demonstrated that GFG consists of glucose, galactose, and fucose, with a molecular weight of 488 Da. Nuclear magnetic resonance analysis showed that it has a different structure than that of 2'-fucosyllactose (2'-FL), even though they have the same monosaccharide composition. In vitro prebiotic experiments were conducted to evaluate the differences in the utilization of three selected carbohydrates by fourteen bacterial strains. In comparison with 2'-FL, GFG could be utilized by more beneficial bacteria, leading to generate more short-chain fatty acids. Moreover, GFG could not promote the proliferation of Escherichia coli. This work describes a novel fucosylated oligosaccharide and its preparation method, and the obtained trisaccharide may serve as a promising candidate for fucosylated human milk oligosaccharides.

A novel glucofucobiose with potential prebiotic activity prepared from the exopolysaccharides of Clavibacter michiganensis M1

Fucose and fucosylated oligosaccharides have important applications in various industries owing to their prebiotic, anti-inflammatory, anticoagulant, and antiviral activities. Here, we aimed to obtain fucosylated oligosaccharides using the acidolysis method to depolymerize exopolysaccharides extracted from Clavibacter michiganensis M1. Based on structural analysis, the prepared glucofucobiose was found to consist of d-glucose and l-fucose, with a molecular weight of 326 Da and a structure of d-Glcp-β-(1→4)-l-Fucp. The prebiotic activity of glucofucobiose was compared with that of 2'-fucosyllactose (2'-FL), the most abundant oligosaccharide in human milk. According to the results, glucofucobiose could significantly promote the proliferation of six probiotic strains, and short-chain fatty acid production of five probiotic strains on glucofucobiose was substantially higher than that on 2'-FL at 48 h of fermentation. Overall, this study proposed a new technology for obtaining fucosylated oligosaccharides. The prepared glucofucobiose was found to exhibit potential prebiotic activity and should be further assessed.

Fucose-containing bacterial exopolysaccharides: Sources, biological activities, and food applications

Bacterial exopolysaccharides are high molecular weight polysaccharides that are secreted by a wide range of bacteria, with diverse structures and easy preparation. Fucose, fucose-containing oligosaccharides (FCOs), and fucose-containing polysaccharides (FCPs) have important applications in the food and medicine fields, including applications in products for removing Helicobacter pylori and infant formula powder. Fucose-containing bacterial exopolysaccharide (FcEPS) is a prospective source of fucose, FCOs, and FCPs. This review systematically summarizes the common sources and applications of FCPs and FCOs and the bacterial strains capable of producing FcEPS reported in recent years. The repeated-unit structures, synthesis pathways, and factors affecting the production of FcEPS are reviewed, as well as the degradation methods of FcEPS for preparing FCOs. Finally, the bioactivities of FcEPS, including anti-oxidant, prebiotic, anti-cancer, anti-inflammatory, anti-viral, and anti-microbial activities, are discussed and may serve as a reference strategy for further applications of FcEPS in the functional food and medicine industries.

Structural Characterization and Anticoagulant Activity of a 3-O-Methylated Heteroglycan From Fruiting Bodies of Pleurotus placentodes

Pleurotus placentodes, a fungus, belongs to the Pleurotaceae family. The aim of the present study was to characterize the structure of a novel polysaccharide from fruiting bodies of P. placentodes (PPp-W) and evaluate its anticoagulant activity in vitro. The high-performance liquid chromatography and GC–MS analysis indicated that PPp-W with a molecular weight of 27.4 kDa was mainly composed of mannose (17.56%), glucose (6.37%), galactose (44.89%), and fucose (1.22%) with a certain amount of 3-O-methyled galactose. SEM, XRD, and AFM combined with Congo red test revealed that PPp-W was an irregular curly sheet with triple-helix conformation. The FT-IR, methylation, and nuclear magnetic resonance analysis indicated that PPp-W contained→6)-α-D-Galp-(1→, →6)-3-O-Me-α-D-Galp-(1→and →2, 6)-α-D-Galp-(1→ as main chain, partially substituted at O-2 and O-6 by non-reducing ends of β-D-Manp-(1→ and β-L-Fucp-(1→ with a small amount of α-1,3-linked-Glcp in backbone. PPp-W could significantly prolong APTT (12.9 ± 0.42 s, p < 0.001) and thrombin time (39.9 ± 0.28 s, p < 0.01) compared with the control group (11.45 ± 0.071 s and 38.05 ± 0.21 s), which showed that PPp-W had anticoagulant activity. These studies suggested that PPp-W was a 3-O-methylated heteroglycan and might be suitable for functional foods and natural drugs as an anticoagulant ingredient, which provided a basis for the application of polysaccharides from P. placentodes.

Genome sequence analysis of Cronobacter phage PF-CE2 and proposal of a new species in the genus Pseudotevenvirus

The genome of a Cronobacter sakazakii M1 phage named PF-CE2 was characterized in this work, and a new species named "Cronobacter virus PF-CE2", in the genus Pseudotevenvirus of the subfamily Tevenvirinae of the family Myoviridae is proposed. The Gp190 gene of phage PF-CE2 is predicted to encode a bacteriophage-borne glycanase that is capable of degrading fucose-containing exopolysaccharides produced by C. sakazakii M1. Furthermore, we propose changing the taxonomic status of eight additional phages based on nucleotide sequence comparisons. This work provides a theoretical basis for subsequent heterologous expression of the phage PF-CE2 glycanase and provides an important reference for the preservation and sharing of these phages.