The structure of the glucuronoxylomannan produced by culinary-medicinal yellow brain mushroom (Tremella mesenterica Ritz.:Fr., Heterobasidiomycetes) grown as one cell biomass in submerged culture

Nature's Own Pharmacy: Mushroom-Based Chemical Scaffolds and Their Therapeutic Implications

Mushrooms are new potential sources of valuable medicines, long neglected because of difficulties experienced in their cultivation. There is a large variety of medicinal mushrooms which possess significant therapeutic properties and are used as medications for various diseases because they contain several novel highly bioactive components. Medicinal mushrooms can be identified based on their morphology, size, mass, and the color of the stalk, cap and spore, and attachment to the stalk. Medicinal mushrooms possess a variety of important biological activities and are used as antioxidants, hepatoprotectors, anticancer, antidiabetic, anti-inflammatory, antiaging, antiviral, antiparasitic, and antimicrobial agents, among others. This review provides a basic overview of the chemical scaffolds present in mushrooms and their therapeutic implications in the human body.

A polysaccharide NAP-3 from Naematelia aurantialba: Structural characterization and adjunctive hypoglycemic activity

A novel polysaccharide (NAP-3) was isolated and purified from Naematelia aurantialba after water extraction. The structure of NAP-3, which was determined by FT-IR, HPLC, GC-MS, and NMR, indicated that NAP-3 was a homogeneous polysaccharide with the molecular weight of 428 kDa, mainly consisted of β-1, 3-D-Manp, β-1, 2, 3-D-Manp, β-D-Xylp, β-1, 4-D-Glcp, β-1, 4-D-Rhap in a molar ratio of 6.49: 1.11: 2.4: 0.13: 0.83. In vitro α-glucosidase and α-amylase inhibitory assay showed that NAP-3 had a low IC₅₀ value, which exhibited similar enzyme inhibitory activity as acarbose. NAP-3 was evaluated as an adjuvant with metformin for antidiabetic therapy in HFD/STZ-induced diabetic mice and insulin resistance HepG2 cells. The combination of NAP-3 and metformin in diabetic mice exhibited significant hypoglycemic activity, reducing body weight, serum insulin levels, glucose tolerance, insulin tolerance, and increasing antioxidant levels compared to metformin alone. The combination of NAP-3 and metformin improved oxidative stress by increasing ROS clearance, thereby enhancing glucose uptake in HepG2 cells. This study provided new data for the study of Naematelia aurantialba polysaccharides and offers a new adjuvant therapy for the treatment of diabetes.

Chemical Constituents and Molecular Mechanism of the Yellow Phenotype of Yellow Mushroom (Floccularia luteovirens)

(1) Background: Yellow mushroom (Floccularia luteovirens) is a natural resource that is highly nutritional, has a high economic value, and is found in Northwest China. Despite its value, the chemical and molecular mechanisms of yellow phenotype formation are still unclear. (2) Methods: This study uses the combined analysis of transcriptome and metabolome to explain the molecular mechanism of the formation of yellow mushroom. Subcellular localization and transgene overexpression techniques were used to verify the function of the candidate gene. (3) Results: 112 compounds had a higher expression in yellow mushroom; riboflavin was the ninth most-expressed compound. HPLC showed that a key target peak at 23.128 min under visible light at 444 nm was Vb2. All proteins exhibited the closest relationship with Agaricus bisporus var. bisporus H97. One riboflavin transporter, CL911.Contig3_All (FlMCH5), was highly expressed in yellow mushrooms with a different value (log₂ fold change) of −12.98, whereas it was not detected in white mushrooms. FlMCH5 was homologous to the riboflavin transporter MCH5 or MFS transporter in other strains, and the FlMCH5-GFP fusion protein was mainly located in the cell membrane. Overexpression of FlMCH5 in tobacco increased the content of riboflavin in three transgenic plants to 26 μg/g, 26.52 μg/g, and 36.94 μg/g, respectively. (4) Conclusions: In this study, it is clear that riboflavin is the main coloring compound of yellow mushrooms, and FlMCH5 is the key transport regulatory gene that produces the yellow phenotype.

Approaches to Investigate Selective Dietary Polysaccharide Utilization by Human Gut Microbiota at a Functional Level

The human diet is temporally and spatially dynamic, and influenced by culture, regional food systems, socioeconomics, and consumer preference. Such factors result in enormous structural diversity of ingested glycans that are refractory to digestion by human enzymes. To convert these glycans into metabolizable nutrients and energy, humans rely upon the catalytic potential encoded within the gut microbiome, a rich collective of microorganisms residing in the gastrointestinal tract. The development of high-throughput sequencing methods has enabled microbial communities to be studied with more coverage and depth, and as a result, cataloging the taxonomic structure of the gut microbiome has become routine. Efforts to unravel the microbial processes governing glycan digestion by the gut microbiome, however, are still in their infancy and will benefit by retooling our approaches to study glycan structure at high resolution and adopting next-generation functional methods. Also, new bioinformatic tools specialized for annotating carbohydrate-active enzymes and predicting their functions with high accuracy will be required for deciphering the catalytic potential of sequence datasets. Furthermore, physiological approaches to enable genotype-phenotype assignments within the gut microbiome, such as fluorescent polysaccharides, has enabled rapid identification of carbohydrate interactions at the single cell level. In this review, we summarize the current state-of-knowledge of these methods and discuss how their continued development will advance our understanding of gut microbiome function.

Biocontrol Properties of Basidiomycetes: An Overview

In agriculture, there is an urgent need for alternate ecofriendly products to control plant diseases. These alternate products must possess preferable characteristics such as new modes of action, cost effectiveness, biodegradability, and target specificity. In the current scenario, studies on macrofungi have been an area of importance for scientists. Macrofungi grow prolifically and are found in many parts of the world. Basidiomycetes (mushrooms) flourish ubiquitously under warm and humid climates. Basidiomycetes are rich sources of natural antibiotics. The secondary metabolites produced by them possess antimicrobial, antitumor, and antioxidant properties. The present review discusses the potential role of Basidiomycetes as anti-phytofungal, anti-phytobacterial, anti-phytoviral, mosquito larvicidal, and nematicidal agents.

Characteristics and Antitumor Activity of Morchella esculenta Polysaccharide Extracted by Pulsed Electric Field

Polysaccharides from Morchella esculenta have been proven to be functional and helpful for humans. The purpose of this study was to investigate the chemical structure and anti-proliferating and antitumor activities of a Morchella esculenta polysaccharide (MEP) extracted by pulsed electric field (PEF) in submerged fermentation. The endo-polysaccharide was separated and purified by column chromatography and Gel permeation chromatography, and analyzed by gas chromatography. The MEP with an average molecular weight of 81,835 Da consisted of xylose, glucose, mannose, rhamnose and galactose at the ratio of 5.4:5.0:6.5:7.8:72.3. Structure of MEP was further analyzed by Fourier-transform infrared spectroscopy and ¹H and ¹³C liquid-state nuclear magnetic resonance spectroscopy. Apoptosis tests proved that MEP could inhibit the proliferation and growth of human colon cancer HT-29 cells in a time- and dose-dependent manner within 48 h. This study provides more information on chemical structure of anti-proliferating polysaccharides isolated from Morchella esculenta.

Differences in Cellulosic Supramolecular Structure of Compositionally Similar Rice Straw Affect Biomass Metabolism by Paddy Soil Microbiota

Because they are strong and stable, lignocellulosic supramolecular structures in plant cell walls are resistant to decomposition. However, they can be degraded and recycled by soil microbiota. Little is known about the biomass degradation profiles of complex microbiota based on differences in cellulosic supramolecular structures without compositional variations. Here, we characterized and evaluated the cellulosic supramolecular structures and composition of rice straw biomass processed under different milling conditions. We used a range of techniques including solid- and solution-state nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy followed by thermodynamic and microbial degradability characterization using thermogravimetric analysis, solution-state NMR, and denaturing gradient gel electrophoresis. These measured data were further analyzed using an "ECOMICS" web-based toolkit. From the results, we found that physical pretreatment of rice straw alters the lignocellulosic supramolecular structure by cleaving significant molecular lignocellulose bonds. The transformation from crystalline to amorphous cellulose shifted the thermal degradation profiles to lower temperatures. In addition, pretreated rice straw samples developed different microbiota profiles with different metabolic dynamics during the biomass degradation process. This is the first report to comprehensively characterize the structure, composition, and thermal degradation and microbiota profiles using the ECOMICS toolkit. By revealing differences between lignocellulosic supramolecular structures of biomass processed under different milling conditions, our analysis revealed how the characteristic compositions of microbiota profiles develop in addition to their metabolic profiles and dynamics during biomass degradation.

A simple SPR-based method for the quantification of the effect of potential virus inhibitors

Here, we describe a highly sensitive method that allows for the correct quantification of inhibition effect with a higher degree of accuracy directly at the molecular level. The protocol involves two stages, namely serological virus titration in comparison with the same procedure for virus-effector mixture. Owing to the robustness of the analysis this assay can be performed on crude cellular and plant extracts, and therefore it may be suitable for the routine analysis of clinical samples, or in the field. The efficiency of the approach to the quantification of the inhibition effect of polysaccharide glucuronoxylomannan (GXM) on the infection efficiency of the tobacco mosaic virus (TMV) was investigated using advanced serological approaches based on label-free surface plasmon resonance technique. It was shown that GXM drastically decreases the efficiency of TMV infection by blocking up to 70% of the virus shell. The obtained results are in conformity with the method of indicator plant infection.

An antioxidant exopolysaccharide devoid of pro-oxidant activity produced by the soil bacterium Bordetella sp. B4

An exopolysaccharide (EPS) with a molecular weight of 230 kDa, was isolated from Bordetella sp. B4. The EPS was identified as linear alpha-1,6-(6-methyl)-glucan with N-acetyl-D-glucosamine branches at alpha-1, 4-linkages by IR and NMR spectroscopy. The free radical scavenging capacities of EPS on 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+)), H(2)O(2), -OH and lipid peroxidation were 2-, 86-, 134- and 18-fold higher than that of ascorbic acid, respectively. Compared with ascorbic acid, the EPS was more effective in preventing DNA and protein from free radical damage induced by 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH). More significantly, the EPS did not degrade DNA and protein by the pro-oxidant effect in the presence of copper ions and H(2)O(2). Furthermore, EPS could protect human umbilical vein endothelium cells (HUVECs) from high glucose-mediated damage. The production of EPS reached 10.2 g/L in the fermentation medium containing 3.0 g/L cholesterol, suggesting that Bordetella sp. B4 was a potential producer of antioxidant EPS.

Polysaccharides of basidiomycetes. alkali-soluble polysaccharides from the mycelium of white rot fungus Ganoderma lucidum (Curt.: Fr.) P. Karst

Two polysaccharides were isolated from submergedly cultured mycelium of the basidiomycete Ganoderma lucidum by extraction with alkali followed by fractionation with Fehling reagent. The polysaccharides were shown to be a linear (1-->3)-alpha-D-glucan and a highly branched xylomannan containing a backbone built up of (1-->3)-linked alpha-D-mannopyranose residues, the majority of which are substituted at O-4 by single beta-D-xylopyranose residues or by disaccharide fragments beta-D-Manp-(1-->3)-beta-D-Xylp-(1-->. Polysaccharide structures were elucidated by NMR spectroscopy in combination with methylation analysis and periodate oxidation. An interesting feature of the xylomannan is the simultaneous presence of alpha-D-mannopyranose and beta-D-mannopyranose residues, the first forming the backbone, and the second being the non-reducing terminal units of disaccharide side chains.

Structural characterization of a polysaccharide and a beta-glucan isolated from the edible mushroom Flammulina velutipes

Two polysaccharides were isolated from the basidiomycete Flammulina velutipes, via successive hot extraction with water, 2% and 25% aq. KOH, and then submitted to freeze-drying. The precipitate formed by repeated freeze-thawing from the 2% aq. KOH extraction PK2 was analyzed by determination of its monosaccharide composition, as well as by methylation analyses using GC-MS, mono- ((13)C, (1)H NMR) and bidimensional ((1)H (obs.), (13)C HMQC) spectroscopy, and controlled Smith degradations. It was established to be a branched beta-glucan, with a main chain of (1-->3)-linked-Glcp residues, substituted at O-6 by single-unit beta-Glcp side chains. The precipitate formed by repeated freeze-thawing from the 25% KOH extraction PK25 contained Xyl, Man, and Glc and was heterogeneous by HSPEC and extraction with DMSO gave a soluble xylomannan (XM). It was homogeneous with a molar mass 30.8 x 10(4)g/mol (dn/dc=0.186). Using the above chemical analyses, it was a xylomannan with Man and Xyl in a 3:2 molar ratio. Its main chain consisted of (1-->3)-linked alpha-Manp units, mainly substituted at O-4 by beta-Xylp units or with some beta-Xylp-(1-->3)-beta-Xylp groups.

Effects of ingested fruiting bodies, submerged culture biomass, and acidic polysaccharide glucuronoxylomannan of Tremella mesenterica Retz.:Fr. on glycemic responses in normal and diabetic rats

Mushroom polysaccharides have been shown to regulate glucose metabolism. Using male Wistar rats injected with saline (normal rats), streptozotocin (STZ-NT rats), or streptozotocin plus nicotinamide (STZ+NT rats), we investigated the hypoglycemic activity of orally ingested fruiting bodies (FB), submerged culture biomass (CM), or the acidic polysaccharide glucuronoxylomannan (GXM) of Tremella mesenterica, an edible jelly mushroom. Our results demonstrated that FB ingestion significantly attenuated the elevated blood glucose levels in an oral glucose tolerance test (OGTT) in STZ-NT rats. However, in STZ+NT rats, FB, CM, and GXM ingestion significantly attenuated the increases in food and water intake, 2-h postprandial blood glucose concentrations, and blood glucose levels in OGTT. Moreover, FB and GXM ingestion significantly decreased serum concentration of fructosamine in STZ+NT rats. Our results indicated that T. mesenterica might be developed as a potential oral hypoglycemic agent or functional food for diabetic patients and for persons with high risk for diabetes mellitus.