Interactions of lipid metabolism and intestinal physiology with Tremella fuciformis Berk edible mushroom in rats fed a high-cholesterol diet with or without Nebacitin

Microbiological quality and safety of fresh mushroom products at retail level in Korea

Several investigations and recalls have demonstrated that Listeria monocytogenes can occur on mushrooms. This study aimed to assess the microbiological quality and safety of four types of edible mushrooms (Flammulina velutipes, Pleurotus ostreatus, Pleurotus eryngii, and Agaricus bisporus) available in the Korean market, and to evaluate the prevalence of Listeria spp., including L. monocytogenes. Results revealed that out of 100 samples tested, 16% (32/200) were positive for Listeria spp. Of the Listeria-positive samples, five strains of Listeria innocua were detected. The total microbial counts ranged from 0.79 to 5.84 log CFU/g, with F. velutipes exhibiting the highest microbial load (mean 5.03 log CFU/g). These findings provide significant data for risk assessment and emphasize the need for continued monitoring of the microbiological safety of edible mushrooms.

Extraction, isolation, purification, derivatization, bioactivity, structure-activity relationship and application of polysaccharides from white jellyfungus

White jellyfungus is one of the most popular nutritional supplements. The polysaccharide (WJP) is an important active component of white jellyfungus, it not only has a variety of biological activities but also is non-toxic to humans. So, many scholars have carried out different researches on WJP. However, the lack of a detailed summary of WJP limits the scale of industrial development of WJP. Herein, the research progress of WJP in extraction, isolation, structure, derivatization and structure-activity relationship was reviewed. Different extraction methods were compared, the activity and application of WJP were summarized, and the structure-activity relationship of WJP was emphasized in order to provide effective theoretical support for improving the utilization of WJP and promoting the application of related industries. This article is protected by copyright. All rights reserved.

Yeast exopolysaccharides and their physiological functions

Mounting evidence indicated the capability of various microorganisms in biosynthesis of exopolysaccharides (EPSs). A wide range of evidence extensively investigated the ability of bacterial species for EPS synthesis and their favorable effects, so little is known regarding yeast species. Many factors like composition of growth media and fermentation conditions are related to the structural and physical properties of EPSs. The EPS protects the producer yeast strain against extreme environment. Researchers proposed that yeast EPSs have priority over bacterial EPSs because of high yields of EPS biosynthesis and easy separation methods from growth media. Besides, they have drawn increasing attention due to their interesting biological activities, food, pharmaceutical, and cosmetics applications. Although a limited number of studies exist, this review aims to highlight the EPS structure and various applications of known yeast species in detail.

Tremella polysaccharide: The molecular mechanisms of its drug action

Tremella fuciformis is an edible medicinal mushroom well known as "Yiner" or "Baimuer" in China and has been used as a Chinese herb for many years. T. fuciformis polysaccharide (TFPS) has been identified as a major bioactive component. Different experimental conditions can obtain different TFPS fractions, which makes TFPS a mixture of different polysaccharides with the molecular weight ranging from 5.82×10⁵Da to 3.74×10⁶Da. The monosaccharides detected in TFPS include mannose, xylose, fucose, glucuronic acid, glucose, and galactose. One characterized TFPS chemical structure consists of a linear (1→3)-linked α-d-mannose backbone with highly branched β-d-xylose, α-d-fucose and β-d-glucuronic acid as the side chains. TFPS shows multiple physiological and healthy promoting effects including immunomodulation, antitumor, anti-oxidation, anti-aging, hypoglycemic, hypolipidemic, neuroprotection, and other effects. As a result, "Tremella Polysaccharide Enteric-coated Capsules" was approved by Chinese Food and Drug Administration (SFDA) in 2002 for treating cancer patients with leukopenia induced by chemotherapy and radiotherapy. It is also used as adjuvant drug for treating chronic persistent hepatitis and chronic active hepatitis. In this chapter, 113 independent studies involving in biochemical, pharmacological, and clinical studies of TFPS during the past 46 years (1972-2018) on the base of PubMed, CNKI (China National Knowledge Infrastructure) and Wanfang database search are summarized. TFPS shows efficacy for all types of human diseases in the reported clinical studies. The structure, molecular mechanisms of the immunomodulation, antitumor, anti-oxidation, anti-aging, hypoglycemic, hypolipidemic, preclinical and clinical efficacy are discussed to provide a general picture of TFPS as a clinically used drug.

Protective effect of Tremella fuciformis Berk extract on LPS-induced acute inflammation via inhibition of the NF-κB and MAPK pathways

Tremella fuciformis Berk (TFB) has long been used as a traditional medicine in Asia. Although TFB exhibits antioxidant and anti-inflammatory effects, the mechanisms of action responsible have remained unknown. We confirmed the anti-inflammatory effects of Tremella fuciformis Berk extract (TFE) in RAW 264.7 cells and observed significantly suppressed LPS-induced iNOS/NO and COX-2/PGE2 production. TFE also suppressed LPS-induced IKK, IkB, and p65 phosphorylation, as well as LPS-induced translocation of p65 from the cytosol. Additionally, TFE inhibited LPS-induced phosphorylation of MAPKs. In an acute inflammation study, oral administration of TFE significantly inhibited LPS-induced IL-1β, IL-6 and TNF-α production and iNOS and COX-2 expression. The major bioactive compounds from TFB extract were identified as gentisic acid, protocatechuic acid, 4-hydroxybenzoic acid, and coumaric acid. Among these compounds, protocatechuic acid showed the strongest inhibitory effects on LPS-induced NO production in RAW 264.7 cells. Overall, these results suggest that TFE is a promising anti-inflammatory agent that suppresses iNOS/NO and COX-2/PGE2 expression, as well as the NF-κB and MAPK signaling pathways.

Comparison of Immunomodulatory and Anticancer Activities in Different Strains of Tremella fuciformis Berk

Tremella fuciformis Berk (TF) is a common edible and medicinal mushroom, and has long been used in food and in Chinese medicine. It possesses anticancer, anti-inflammation, anti-oxidative, and neuroprotective abilities. Since their cultivation is a problem, TFs in Taiwan are primarily imported from China, which has a problem with pesticide residues. Thus, the question of whether the Taiwan cultivated TFs, T1, and T6 showed similar or even better results than TFs from China (CH) was assessed in the present study. The results of the physicochemical tests of these TFs showed that T1 extracted by hot water (T1H) has the highest concentration of polysaccharide; meanwhile, T6 extracted by cold water (T6C) showed the highest amount of protein. Regarding the immune modulatory effects of these TFs, hot water extracts of these TFs augmented significantly the inducible nitric oxide synthetase (iNOS), interleukin (IL)-6, and tumor necrosis factor (TNF)-[Formula: see text] mRNA expression than those of cold water extracts. On the other hand, the cold water extracts of TFs, especially of T1C, obviously suppressed cancer cell survival better than those of hot water extracts. Interestingly, we found that hot water extracts of TFs may augment necrotic cell death, whereas, cold water extracts of TFs induce apoptosis. Furthermore, we also showed that these TFs activate caspase-3 cleavage, up regulate the Bax/Bcl-2 ratio, and decrease MMP-9 expressions in PC-3 cells. Taken together, our results indicated that T1 and T6 strains of TFs showed the similar immune modulatory and anticancer abilities were better than the CH strain of TFs.

Inhibitory effect on in vitro LDL oxidation and HMG Co-A reductase activity of the liquid-liquid partitioned fractions of Hericium erinaceus (Bull.) Persoon (lion's mane mushroom)

Oxidation of low-density lipoprotein (LDL) has been strongly suggested as the key factor in the pathogenesis of atherosclerosis. Mushrooms have been implicated in having preventive effects against chronic diseases due especially to their antioxidant properties. In this study, in vitro inhibitory effect of Hericium erinaceus on LDL oxidation and the activity of the cholesterol biosynthetic key enzyme, 3-hydroxy-3-methyl glutaryl coenzyme A (HMG Co-A) reductase, was evaluated using five liquid-liquid solvent fractions consisting of methanol : dichloromethane (M : DCM), hexane (HEX), dichloromethane (DCM), ethyl acetate (EA), and aqueous residue (AQ). The hexane fraction showed the highest inhibition of oxidation of human LDL as reflected by the increased lag time (100 mins) for the formation of conjugated diene (CD) at 1 µg/mL and decreased production (68.28%, IC50 0.73 mg/mL) of thiobarbituric acid reactive substances (TBARS) at 1 mg/mL. It also mostly inhibited (59.91%) the activity of the HMG Co-A reductase at 10 mg/mL. The GC-MS profiling of the hexane fraction identified the presence of myconutrients: inter alia, ergosterol and linoleic acid. Thus, hexane fraction of Hericium erinaceus was found to be the most potent in vitro inhibitor of both LDL oxidation and HMG Co-A reductase activity having therapeutic potential for the prevention of oxidative stress-mediated vascular diseases.

Molecular cloning and function characterization of a new macrophage-activating protein from Tremella fuciformis

Silver ear mushroom ( Tremella fuciformis ) is an edible fungus with health benefits. In this study, we purified a new T. fuciformis protein (TFP) and demonstrated its ability to activate primary murine macrophages. The isolation procedure involved ammonium sulfate fractionation and ion exchange chromatography. TFP naturally formed a 24 kDa homodimeric protein and did not contain glycan residues. The TFP gene was cloned using the rapid amplification of cDNA ends method, and the cDNA sequence of TFP was composed of 408 nucleotides with a 336 nucleotide open reading frame encoding a 112 amino acid protein. TFP was capable of stimulating TNF-α, IL-1β, IL-1ra, and IL-12 production in addition to CD86/MHC class II expression, mRNA expression of M1-type chemokines, and nuclear NF-κB accumulation in murine peritoneal macrophage cells. Furthermore, TFP failed to stimulate TLR4-neutralized and TLR4-knockout macrophages, suggesting that TLR4 is a required receptor for TFP signaling on macrophages. Taken together, these results indicate that TFP may be an important bioactive compound from T. fuciformis that induces M1-polarized activation through a TLR4-dependent NF-κB signaling pathway.

Long-Term Regeneration and Functional Recovery of a 15 mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits

Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air plasma activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15 mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits.

Branching structure and chain conformation of water-soluble glucan extracted from Auricularia auricula-judae

A water-soluble neutral polysaccharide (AF1) was extracted from Auricularia (A.) auricula-judae with 0.15 M aqueous NaCl at 80-100 °C. Its chemical components and structure were analyzed by GC, GC-MS, and NMR. AF1 was identified as a β-(1→3)-D-glucan with two β-(1→6)-D-glucosyl residues for every three main chain glucose residues, showing a comb-branched structure. The M(w) values of AF1 in both aqueous solution and DMSO determined by LLS and SEC-LLS were in the narrow range of 2.07-2.15 × 10(6), indicating AF1 existed as single chains in the two solvents. The high intrinsic viscosity [η] of 1753 mL/g and the structure-sensitive parameter ρ (≡R(g)/R(h)) value of 2.3 in water revealed that AF1 existed as stiff chain conformation. Moreover, we directly observed the extended stiff chain conformation by AFM. The branching structure led to the water solubility of AF1, and the intramolecular hydrogen bonds sustained the stiff chain conformation. The rheological results showed that this polysaccharide aqueous solution had higher viscosity than even xanthan, a pronounced thickening agent. This work provided important information for developing new thickeners in food fields, and how neutral polysaccharides can be used as good candidates.

Protective effects of white button mushroom (Agaricus bisporus) against hepatic steatosis in ovariectomized mice as a model of postmenopausal women

Nonalcoholic fatty liver disease (NAFLD) includes various hepatic pathologies ranging from hepatic steatosis to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Estrogen provides a protective effect on the development of NAFLD in women. Therefore, postmenopausal women have a higher risk of developing NAFLD. Hepatic steatosis is an early stage of fatty liver disease. Steatosis can develop to the aggressive stages (nonalcoholic steatohepatitis, fibrosis and cirrhosis). Currently, there is no specific drug to prevent/treat these liver diseases. In this study, we found that white button mushroom (WBM), Agaricus Bisporus, has protective effects against liver steatosis in ovariectomized (OVX) mice (a model of postmenopausal women). OVX mice were fed a high fat diet supplemented with WBM powder. We found that dietary WBM intake significantly lowered liver weight and hepatic injury markers in OVX mice. Pathological examination of liver tissue showed less fat accumulation in the livers of mice on WBM diet; moreover, these animals had improved glucose clearance ability. Microarray analysis revealed that genes related to the fatty acid biosynthesis pathway, particularly the genes for fatty acid synthetase (Fas) and fatty acid elongase 6 (Elovl6), were down-regulated in the liver of mushroom-fed mice. In vitro mechanistic studies using the HepG2 cell line showed that down-regulation of the expression of FAS and ELOVL6 by WBM extract was through inhibition of Liver X receptor (LXR) signaling and its downstream transcriptional factor SREBP1c. These results suggest that WBM is protective against hepatic steatosis and NAFLD in OVX mice as a model for postmenopausal women.

Effect of Tremella fuciformis on the neurite outgrowth of PC12h cells and the improvement of memory in rats

We investigated the neuritogenic effects of Tremella fuciformis (TF), which has been valued in traditional Chinese medicine as a remedy with nutritive and tonic actions, on PC12h cells. The cognitive improving effects of TF on scopolamine-induced (2 mg/kg, s.c.) amnesia in rats were also evaluated with using the Morris water maze task and by performing choline acetyltransferase (ChAT) immunohistochemistry. The water extract of TF (0.01-1 microg/ml) promoted neurite outgrowth of the PC12h cells in a dose dependent manner. TF was highly efficient at the concentration range of 0.1-1 microg/ml. Oral daily treatment with TF (100 or 400 mg/kg) for 14 consecutive days significantly reversed the scopolamine-induced deficit in learning and memory, and it alleviated decrease in cholinergic immunoreactivity induced by scopolamine in the medial septum and hippocampus. The results demonstrate that the promotion of neuritogenesis in neuronal culture cells by TF water extract is related with its activity for improving the performance of rats on a spatial learning and memory task. Moreover, the impairments of spatial learning and memory may be attributable to the decrease in activation of the septohippocampal cholinergic system and that TF ameliorated learning and memory deficits partly through its increasing the central cholinergic activity. Therefore, TF could represent a potentially useful agent that is able to improve the function of impaired cognitive processes.

Chromosomal integration of the Vitreoscilla hemoglobin gene and its physiological actions in Tremella fuciformis

The Vitreoscilla hemoglobin (VHb) gene was expressed in yeast-like conidia (YLCs) of Tremella fuciformis (T. fuciformis) to increase cell density in submerged fermentation by enhancing oxygen uptake. With the intention of doing this, an integrated expression vector containing the VHb gene and the hygromycin B phosphotransferase (hph) gene derived from Escherichia coli (E. coli) as the selectable marker was constructed, and then transformed into protoplasts of YLCs from T. fuciformis with restriction enzyme-mediated DNA integration (REMI). Hygromycin-resistant transformants had been generated during the transformation. Molecular evidences including PCR assay, Southern blotting, and Western blot analysis indicated the VHb gene had been integrated into the genome of transgenic T. fuciformis strains and was expressed successfully. Shake-flask fermentation and bioreactor cultivation results showed that the expression of VHb in this fungus could enhance growth of YLCs. The final cell density was higher in the culture of VHb-expressing strain than that of the wild-type strain. Moreover, these results also suggested that CaMV35S promoter was capable of driving the expression of heterologous genes in T. fuciformis.