The function and application of edible fungal polysaccharides.

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Edible fungal polysaccharides (EFPs) are a variety of bioactive macromolecular which isolated from fruiting bodies, mycelia or fermentation broths of edible or medicinal fungus. Increasing researches have confirmed that EFPs possess multiple biological activities both in vitro and in vivo settings, including antioxidant, antiviral, anti-inflammatory, immunomodulatory, anti-tumor, hypoglycemic, hypolipidemic, and regulating intestinal flora activities. As a result, they have emerged as a prominent focus in the healthcare, pharmaceutical, and cosmetic industries. Fungal EFPs have safe, non-toxic, biodegradable, and biocompatible properties with low immunogenicity, bioadhesion ability, and antibacterial activities, presenting diverse potential applications in the food industries, cosmetic, biomedical, packaging, and new materials. Moreover, varying raw materials, extraction, purification, chemical modification methods, and culture conditions can result in variances in the structure and biological activities of EFPs. The purpose of this review is to provide comprehensively and systematically organized information on the structure, modification, biological activities, and potential applications of EFPs to support their therapeutic effects and health functions. This review provides new insights and a theoretical basis for prospective investigations and advancements in EFPs in fields such as medicine, food, and new materials.

Effect of water film evaporation on the shale gas transmission in inorganic nanopores under viscosity.

Shale gas reservoirs generally have ultra-low water saturation, and the water in reservoirs is closely bound to the walls of inorganic nanopores, forming a water film structure on the hydrophilic surface. When shale gas enters the inorganic nanopores, the water films in the inorganic pores will be removed by evaporation instead of being driven away by the gas, which increases the difficulty of predicting production during shale gas extraction. Based on molecular dynamics simulations, a water film evaporation model is proposed, considering the evaporation of water films during shale gas transport and the influence of water film evaporation on the shale gas transport mechanism. The Green-Kubo method is employed to calculate the viscosity of the water film. The evaporation flux of the water film under the influence of viscosity is discussed in the evaporation model. The transport mechanisms of shale gas in nanopores and the effect of water film evaporation on shale gas transport mechanisms are analyzed in detail. The result indicates that the water films in the inorganic nanopores are constrained on the hydrophilic surface, and the viscosity normal to the surface of the water film of 4 Å is 0.005 26 Pa⋅S, which is 6.12 times the reference value of viscosity at 298 K. In the process of water film evaporation, the evaporation flux of the water film is influenced by viscosity. In the study of the shale gas transport mechanism, water films in inorganic nanopores can hinder the surface diffusion of the methane molecules adsorbed on boundary and significantly reduce the mass flux of shale gas.

Application of the mushroom volatile 1-octen-3-ol to suppress a morel disease caused by Paecilomyces penicillatus.

Morels (Morchella spp.) are of great economic and scientific value. Paecilomyces penicillatus can cause white mold disease (WMD) widely emerging on morel ascocarps and is also a potential factor causing morel fructification failure. 1-octen-3-ol is a mushroom volatile compound with broad-spectrum antimicrobial activities. This study aimed to control the morel disease caused by P. penicillatus through suppressing P. penicillatus in the soil cultivated with Morchella sextelata using 1-octen-3-ol. Safe concentration of 1-octen-3-ol was estimated by comparing its inhibitory effect against P. penicillatus and M. sextelata, respectively, with mycelium-growth experiments on agar plates. The results showed that M. sextelata possesses a higher tolerance to 1-octen-3-ol than P. penicillatus with a 1-octen-3-ol concentration between 0 and 200 µL/L. Based on that, a sandy soil was supplemented with low (50 µL/L) or high concentration (200 µL/L) of 1-octen-3-ol. The effects of 1-octen-3-ol on soil microbial communities, WMD incidence, and morel yield were investigated. Compared to the non-supplemented control group, the incidence of WMD and the proportion of Paecilomyces in the soils of low- and high-concentration treatment groups were significantly decreased, corresponding to a significant increase in morel ascocarp yield. It suggests that 1-octen-3-ol effectively suppressed P. penicillatus in the soil, thereby reducing the severity of WMD and improving the morel yield. The diversity of soil bacterial communities was also altered by 1-octen-3-ol supplement. The proportion of Rhodococcus spp. in the soil was positively correlated with the 1-octen-3-ol concentration and ascocarp yield, suggesting its potential role in improving morel yield. KEY POINTS: • A novel method for morel disease suppression was proposed. • Paecilomyces in soil affects white mold disease and fructification yield of morel. • 1-Octen-3-ol suppresses Paecilomyces and alters bacterial community in soil.

Large-scale commercial cultivation of morels: current state and perspectives.

Since morels were first successfully cultivated commercially in Sichuan in 2012, morel cultivation has expanded to more than 20 provinces in China. The highest yield currently reaches 15,000 kg/ha. Morel cultivation is characterized by its environmental friendliness, short cycle length, and high profit. However, the yield obtained is unstable which makes morel cultivation a high-risk industry. Although 10 production cycles have passed, there is still a gap between morel cultivation practice and our basic knowledge of morel biology. This mini-review concentrates on the development needs of morel cultivation. We illustrate the key techniques used in the large-scale commercial cultivation of morels and their relevant studies, including nutritional requirements, mechanisms of nutrient bag, soil type, vegetative and reproductive growth conditions, and disease control. This review will be a useful practical reference for the commercial artificial cultivation of morels and promoting the vital technologies required. KEY POINTS: •Unstable yield still exists after commercial cultivation of morels realized. •There is a gap between cultivation practice and our knowledge of morel biology. •Key techniques are illustrated for morel cultivation practice.

Multi-omic analyses of exogenous nutrient bag decomposition by the black morel Morchella importuna reveal sustained carbon acquisition and transferring.

The black morel (Morchella importuna Kuo, O'Donnell and Volk) was once an uncultivable wild mushroom, until the development of exogenous nutrient bag (ENB), making its agricultural production quite feasible and stable. To date, how the nutritional acquisition of the morel mycelium is fulfilled to trigger its fruiting remains unknown. To investigate the mechanisms involved in ENB decomposition, the genome of a cultivable morel strain (M. importuna SCYDJ1-A1) was sequenced and the genes coding for the decay apparatus were identified. Expression of the encoded carbohydrate-active enzymes (CAZymes) was then analyzed by metatranscriptomics and metaproteomics in combination with biochemical assays. The results show that a diverse set of hydrolytic and redox CAZymes secreted by the morel mycelium is the main force driving the substrate decomposition. Plant polysaccharides such as starch and cellulose present in ENB substrate (wheat grains plus rice husks) were rapidly degraded, whereas triglycerides were accumulated initially and consumed later. ENB decomposition led to a rapid increase in the organic carbon content in the surface soil of the mushroom bed, which was thereafter consumed during morel fruiting. In contrast to the high carbon consumption, no significant acquisition of nitrogen was observed. Our findings contribute to an increasingly detailed portrait of molecular features triggering morel fruiting.

Intra- and inter-isolate variation of ribosomal and protein-coding genes in Pleurotus: implications for molecular identification and phylogeny on fungal groups.

BACKGROUND: The internal transcribed spacer (ITS), RNA polymerase II second largest subunit (RPB2), and elongation factor 1-alpha (EF1α) are often used in fungal taxonomy and phylogenetic analysis. As we know, an ideal molecular marker used in molecular identification and phylogenetic studies is homogeneous within species, and interspecific variation exceeds intraspecific variation. However, during our process of performing ITS, RPB2, and EF1α sequencing on the Pleurotus spp., we found that intra-isolate sequence polymorphism might be present in these genes because direct sequencing of PCR products failed in some isolates. Therefore, we detected intra- and inter-isolate variation of the three genes in Pleurotus by polymerase chain reaction amplification and cloning in this study. RESULTS: Results showed that intra-isolate variation of ITS was not uncommon but the polymorphic level in each isolate was relatively low in Pleurotus; intra-isolate variations of EF1α and RPB2 sequences were present in an unexpectedly high amount. The polymorphism level differed significantly between ITS, RPB2, and EF1α in the same individual, and the intra-isolate heterogeneity level of each gene varied between isolates within the same species. Intra-isolate and intraspecific variation of ITS in the tested isolates was less than interspecific variation, and intra-isolate and intraspecific variation of RPB2 was probably equal with interspecific divergence. Meanwhile, intra-isolate and intraspecific variation of EF1α could exceed interspecific divergence. These findings suggested that RPB2 and EF1α are not desirable barcoding candidates for Pleurotus. We also discussed the reason why rDNA and protein-coding genes showed variants within a single isolate in Pleurotus, but must be addressed in further research. CONCLUSIONS: Our study demonstrated that intra-isolate variation of ribosomal and protein-coding genes are likely widespread in fungi. This has implications for studies on fungal evolution, taxonomy, phylogenetics, and population genetics. More extensive sampling of these genes and other candidates will be required to ensure reliability as phylogenetic markers and DNA barcodes.

Proteomic Analysis Revealed the Fruiting-Body Protein Profile of Auricularia polytricha.

Auricularia polytricha is one of the most widely cultivated edible mushrooms in China. Many advances have been made to A. polytricha, but there is still no proteomic information of this species. Our current understanding was based upon the translated information of its transcriptome or other relative species. This study presented the proteomic information of fruiting-body proteins by shotgun liquid chromatography and tandem mass spectrometry (LC-MS/MS), which identified 15,508 peptides corresponding to 1850 high-confidence proteins. Of these, 1383 were annotated across the GO subcategories with 829 (44.81%) involved in biological process, 908 (49.08%) in molecular function, and 406 (21.95%) in cellular components. Among these high-confidence proteins, 132 proteins were annotated as carbohydrate-active enzymes, of which 51 were secreted enzymes. Moreover, a number of commercially important enzymes were detected, functioning as auxiliary activity (AA) family 5 glyoxal oxidase, AA5 galactose oxidase, glycoside hydrolase (GH) family 20 hexosaminidase, and GH47 alpha-mannosidase. To the best of our knowledge, this is the first study to characterize A. polytricha proteome, and also fills the gap of our knowledge on the under-developed mushroom species.

Phylogenetic relationship of two popular edible Pleurotus in China, Bailinggu (P. eryngii var. tuoliensis) and Xingbaogu (P. eryngii), determined by ITS, RPB2 and EF1α sequences.

The aims of this study are to assess the utility of the internal transcribed spacer (ITS) region, and partial translation elongation factor (EF1α) and RNA polymerase II (RPB2) genes, for differentiation of Bailinggu, P. eryngii, and P. nebrodensis; to reconstruct phylogenetic relationships between the three species; and to confirm the taxonomic status of Bailinggu based on ribosomal and protein-coding genes. Pairwise genetic distances between Bailinggu, P. eryngii, and related Pleurotus strains were calculated by using the p-distance model, and molecular phylogeny of these isolates was estimated based on ITS, RPB2, and EF1α using maximum parsimony and Bayesian methods. Differences in ITS, RPB2, and EF1α sequences show that Bailinggu, P. eryngii, and P. nebrodensis are distinct at the species level. Phylogenetic analyses reveal that P. eryngii is closer to P. nebrodensis than to Bailinggu. Sequence analyses of ribosomal and protein-coding genes confirm that P. eryngii var. tuoliensis is identical to Bailinggu. P. eryngii var. tuoliensis should be raised to species level or a new name should be introduced for Bailinggu after a thorough investigation into Pleurotus isolates from Ferula in Xinjiang Province. This study helps to resolve uncertainty regarding Bailinggu, P. eryngii and P. nebrodensis, improving the resource management of these strains. ITS, EF1α, and RPB2 sequences can be used to distinguish Bailinggu, P. eryngii and P. nebrodensis as three different species, and P. eryngii var. tuoliensis should be the scientific name for Bailinggu at present.

Identification and characterization of a mesophilic phytase highly resilient to high-temperatures from a fungus-garden associated metagenome.

Phytases are enzymes degrading phytic acid and thereby releasing inorganic phosphate. While the phytases reported to date are majorly from culturable microorganisms, the fast-growing quantity of publicly available metagenomic data generated in the last decade has enabled bioinformatic mining of phytases in numerous data mines derived from a variety of ecosystems throughout the world. In this study, we are interested in the histidine acid phosphatase (HAP) family phytases present in insect-cultivated fungus gardens. Using bioinformatic approaches, 11 putative HAP phytase genes were initially screened from 18 publicly available metagenomes of fungus gardens and were further overexpressed in Escherichia coli. One phytase from a south pine beetle fungus garden showed the highest activity and was then chosen for further study. Biochemical characterization showed that the phytase is mesophilic but possesses strong ability to withstand high temperatures. To our knowledge, it has the longest half-life time at 100 °C (27 min) and at 80 °C (2.1 h) as compared to all the thermostable phytases publicly reported to date. After 100 °C incubation for 15 min, more than 93 % of the activity was retained. The activity was 3102 µmol P/min/mg at 37 °C and 4135 µmol P/min/mg at 52.5 °C, which is higher than all the known thermostable phytases. For the high activity level demonstrated at mesophilic temperatures as well as the high resilience to high temperatures, the phytase might be promising for potential application as an additive enzyme in animal feed.

Comparative analyses of Pleurotus pulmonarius mitochondrial genomes reveal two major lineages of mini oyster mushroom cultivars.

Pleurotus pulmonarius, commonly known as the mini oyster mushroom, is highly esteemed for its crisp texture and umami flavor. Limited genetic diversity among P. pulmonarius cultivars raises concerns regarding its sustainable industrial production. To delve into the maternal genetic diversity of the principal P. pulmonarius cultivars, 36 cultivars and five wild isolates were subjected to de novo sequencing and assembly to generate high-quality mitogenome sequences. The P. pulmonarius mitogenomes had lengths ranging from 69,096 to 72,905 base pairs. The mitogenome sizes of P. pulmonarius and those of other mushroom species in the Pleurotus genus showed a significant positive correlation with the counts of LAGLIDAG and GIY-YIG homing endonucleases encoded by intronic open reading frames. A comparison of gene arrangements revealed an inversion of a fragment containing atp9-nad3-nad2 between P. pulmonarius and P. ostreatus. The mitogenomes of P. pulmonarius were clustered into three distinct clades, two of which were crowded with commercial cultivars. Clade I, all of which possess an inserted dpo gene, shared a maternal origin linked to an ancestral cultivar from Taiwan. Primers were designed to target the dpo gene, potentially safeguarding intellectual property rights. The wild isolates in Clade III exhibited more divergent mitogenomes, rendering them valuable for breeding.

New insights into the stipitate hydnoid fungi Sarcodon, Hydnellum, and the formerly informally defined Neosarcodon, with emphasis on the edible species marketed in Southwest China.

Sarcodon and Hydnellum are two ectomycorrhizal genera of important ecological and economic value in Southwest China, and they are common in the free markets in this region. It was estimated that more than 1,500 tonnes of them were sold as edible per year, but there was little information about the taxonomic placements of these edible mushrooms sold in the markets. Traditional concepts of the two genera have also been challenged recently, and circumscription of Sarcodon and the informally defined clade "Neosarcodon" remained unresolved. In the present study, specimens collected in the field and purchased from the markets in Southwest China were analyzed based on morphological characters and DNA sequences. Phylogeny of the traditional Sarcodon s. lat. and Hydnellum s. lat. was reconstructed from the combined internal transcribed spacer (ITS), nuclear large ribosomal subunit (nLSU) and RNA polymerase II second largest subunit (RPB2) dataset based on expanded samples to reevaluate the taxonomic placements of the two genera. In the present molecular analyses, four distinct clades were recovered and strongly supported: Hydnellum, Neosarcodon, Phellodon and Sarcodon. Neosarcodon is formally introduced as a generic name to include nine species previously placed in Sarcodon, and the delimitation of Sarcodon is revised based on phylogenetic and morphological studies. Phylogenetic analyses also revealed an unexpected species diversity (17 phylogenetic species) of Sarcodon and Hydnellum in the markets; nine phylogenetic species of Sarcodon and eight of Hydnellum were uncovered from the samples collected in the markets. Eight species were resolved in the traditional S. imbricatus complex, with S. imbricatus s.str. being the most common edible stipitate hydnoid fungal species. Three of the edible Hydnellum species (H. edulium, H. subalpinum, and H. subscabrosellum), and five separated from the S. imbricatus complex (Sarcodon flavidus, S. giganteus, S. neosquamosus, S. nigrosquamosus, and S. pseudoimbricatus), are described as new. Three new Chinese records (H. illudens, H. martioflavum, and H. versipelle), and the notable S. imbricatus and S. leucopus are also reported.

The Protective Role of Scorias spongiosa Polysaccharide-Based Microcapsules on Intestinal Barrier Integrity in DSS-Induced Colitis in Mice.

Scorias spongiosa, a type of edible fungus, is beneficial for intestinal health. However, the mechanisms by which polysaccharides derived from S. spongiosa contribute to the integrity of the intestinal barrier have been little investigated. In the present study, 40 C57BL/6J mice were assigned into five groups: (1) Normal; (2) Dextran sulfate sodium (DSS)Administration; (3) DSS + Uncapped polysaccharides; (4) DSS + Low microcapsules; (5) DSS + High microcapsules. After one week of administration of S. spongiosa polysaccharides, all mice, excluding the Normal group, had free access to the drinking water of 3.5% DSS for seven days. Serum and feces were then taken for analysis. Scanning electron microscopy analysis indicated the structure of the micro-capped polysaccharides with curcumin was completed with a rough surface, which differs from the uncapped polysaccharides. Noticeably, S. spongiosa polysaccharides enhanced intestinal barrier integrity as evidenced by increasing the protein levels of Claudin-1, ZO-1 and ZO-2. Low-capped polysaccharides mitigated the DSS-induced oxidative stress by increasing catalase (CAT) concentration and decreasing malondialdehyde (MDA) and myeloperoxidase (MPO) concentrations. Besides, DSS treatment caused a disturbance of inflammation and the contents of IL-1ß, IL-6, TNF-α and CRP were downregulated and the contents of IL-4, IL-10 and IFN-γ were upregulated by S. spongiosa polysaccharides. Research on the potential mechanisms indicated that S. spongiosa polysaccharides inhibited the DSS-triggered activation of NF-κB signaling. Moreover, the JAK/STAT1 and MAPK pathways were suppressed by S. spongiosa polysaccharides in DSS-challenged mice, with Lcap showing the strongest efficacy. 16S rDNA amplicon sequencing revealed that the richness and diversity of the microbial community were reshaped by S. spongiosa polysaccharide ingestion. Therefore, our study substantiated that S. spongiosa polysaccharides exhibited protective effects against colitis mice by reshaping the intestinal microbiome and maintaining the balance of intestinal barrier integrity, antioxidant capacity and colonic inflammation through regulation of the NF-κB-STAT1-MAPK axis.

Hydrated lime promoted the polysaccharide content and affected the transcriptomes of Lentinula edodes during brown film formation.

Brown film formation, a unique developmental stage in the life cycle of Lentinula edodes, is essential for the subsequent development of fruiting bodies in L. edodes cultivation. The pH of mushroom growth substrates are usually adjusted with hydrated lime, yet the effects of hydrated lime on cultivating L. edodes and the molecular mechanisms associated with the effects have not been studied systemically. We cultivated L. edodes on substrates supplemented with 0% (CK), 1% (T1), 3% (T2), and 5% (T3) hydrated lime (Ca (OH)2), and applied transcriptomics and qRT-PCR to study gene expression on the brown film formation stage. Hydrated lime increased polysaccharide contents in L. edodes, especially in T2, where the 5.3% polysaccharide content was approximately 1.5 times higher than in the CK. The addition of hydrated lime in the substrate promoted laccase, lignin peroxidase and manganese peroxidase activities, implying that hydrated lime improved the ability of L. edodes to decompose lignin and provide nutrition for its growth and development. Among the annotated 9,913 genes, compared to the control, 47 genes were up-regulated and 52 genes down-regulated in T1; 73 genes were up-regulated and 44 were down-regulated in T2; and 125 genes were up-regulated and 65 genes were down-regulated in T3. Differentially expressed genes (DEGs) were enriched in the amino acid metabolism, lipid metabolism and carbohydrate metabolism related pathways. The carbohydrate-active enzyme genes up-regulated in the hydrated lime treatments were mostly glycosyl hydrolase genes. The results will facilitate future optimization of L. edodes cultivation techniques and possibly shortening the production cycle.

A Cross-Scale Framework for Modelling Chloride Ions Diffusion in C-S-H: Combined Effects of Slip, Electric Double Layer and Ion Correlation.

Water and chloride ions within pores of cementitious materials plays a crucial role in the damage processes of cement pastes, particularly in the binding material comprising calcium-silicate-hydrates (C-S-H). The migration mechanism of water and chloride ions restricted in C-S-H nanopores is complicated due to the presence of interfacial effects. The special mechanical properties of the solid-liquid interface determine the importance of boundary slip and Electric Double Layer (EDL) and ion diversity in pore solutions determines the difference of the EDL and the stability of water film slip. A cross-scale model covering slip effects, time-varying of EDL and ion correlation needs to be developed so that the interfacial effects concentrated at the pore scale can be extended to affect the overall diffusivity of C-S-H. The statistics of pore size distribution and fractal dimension were used to quantitatively compare the similarities between model and C-S-H structure, thus proving the reliability of cross-scale reconstructed C-S-H transmission model. The results show that the slip effect is the dominant factor affecting the diffusion ability of C-S-H, the contribution of the slip effect is up to 60% and the contribution rate of EDL time-varying only up to about 15%. Moreover, the slip effect is sensitive to both ion correlation and C-S-H inhomogeneity and EDL time-varying is almost insensitive to ion correlation changes. This quantification provides a necessary benchmark for understanding the destructiveness of cement-based materials in the salt rich environment and provides new insights into improving the durability of concrete by changing the solid-liquid interface on the micro-nanoscale.

Flammulina velutipes Polysaccharides Modulate Gut Microbiota and Alleviate Carbon Tetrachloride-Induced Hepatic Oxidative Injury in Mice.

A carbon tetrachloride-induced acute liver injury mouse model is used to study the regulation of gut microbiota and hepatoprotective effect of polysaccharides from Flammulina velutipes (FVPs). The hepatoprotective effect of the FVPs leads to reduced levels of serum aspartate transaminase (AST), alanine aminotransferase (ALT), triglyceride (TG), total cholesterol (TC), total bile acid (TBA) content, and change in liver histopathology. Their anti-oxidant activity is exhibited by decreased levels of hepatic malonaldehyde (MDA) and protein carbonyl (PC) content and increased catalase (CAT) and superoxide dismutase (SOD) content. The anti-inflammatory ability of the FVPs is reflected in a decrease in pro-inflammatory cytokines (including IL-6, IL-1ß, and TNF-α). 16S rRNA sequencing shows that the FVPs change the composition of the gut microbiota. A subsequent metabolomics analysis of the gut bacteria (UHPLC-MS/MS-based) revealed that fatty acid biosynthesis, tryptophan metabolism, and metabolism of xenobiotics by cytochrome P450 play important roles in the hepatoprotective effect. This study provides a potential way to modulate gut microbiota and manage liver diseases using natural products.

Impacts of size reduction and alkaline-soaking pretreatments on microbial community and organic matter decomposition during wheat straw composting.

This study assessed the impacts of size reduction and alkaline-soaking pretreatments on microbial community shifts and organic matter decomposition in wheat straw composting. Bacterial communities were altered by alkaline soaking rather than size reduction, while fungal communities were altered by both pretreatments. Alkaline-soaking pretreatment promoted lignocellulosic saccharification and humification. A combination of both pretreatments increased the proportion of the fungal genus Coprinopsis (39%) at the early stage and promoted the proliferation of Ornithincoccus (15%) at the late stage. This facilitated the mineralization of ammonium N from amino acids; decreased the total lipids, free fatty acids, and nitrate N contents; and greatly improved the germination index of the final composting product to a high level of 149% as tested with radish seeds. The findings demonstrate that the combined application of size reduction and alkaline-soaking pretreatments is an effective strategy for improving the product quality of wheat straw compost.

Scorias spongiosa Polysaccharides Promote the Antioxidant and Anti-Inflammatory Capacity and Its Effect on Intestinal Microbiota in Mice.

Scorias spongiosa, as an edible fungus, has multiple health benefits. However, the effects of S. spongiosa on intestinal health are rarely explored. Hence, our study aims to elaborate on the influences of S. spongiosa polysaccharides (SSPs) on antioxidant, anti-inflammatory, and intestinal microflora in C57BL/6J mice. In the present study, 18 male mice were randomly distributed into three groups: (1) Control group (CON); (2) Low dose SSPs group (LSSP); (3) High dose SSPs group (HSSP). After 14-day administration, the jejunum and serum samples were collected for detection. The results showed that SSPs exert no effects on the growth performance of mice regardless of doses. Meanwhile, SSPs administration reduced the serum pro-inflammatory cytokines and elevated the anti-inflammatory cytokines. Moreover, the antioxidant capacity was elevated by SSPs administration, as evidenced by the increased contents of T-AOC, GSH-Px, and the decreased content of MDA. Mechanistically, the administration of SSPs enhanced the protein abundances of p-Nrf2, Keap1, and HO-1 in mice. The results of 16S rDNA demonstrated that the microbial community and composition were altered by SSPs administration. To summarize, SSPs benefit intestinal health in C57BL/6J mice via a mechanism that involves elevating antioxidant and anti-inflammatory activities and regulating intestinal microbiota.

Comparative analyses of Flammulina filiformis mitochondrial genomes reveal high length polymorphism in intergenic regions and multiple intron gain/loss in cox1.

The golden-needle mushroom Flammulina filiformis is one of the bulk mushroom products in the world. This study obtained complete mitogenomes of 44 wild isolates collected from nine provinces and two artificially bred cultivars of F. filiformis, together with three Flammulina rossica isolates and one Flammulina fennae isolate for comparison. The mitogenome of F. filiformis ranged from 83,540 bp to 90,938 bp, consisting of 14 conserved protein-coding genes (PCGs), two rRNA genes, and 25 tRNA genes. To the best of our knowledge, it contained the highest proportion of intergenic regions compared to the other known Basidiomycota mitogenomes. Introns and intergenic regions were two major contributing factors to the total size of the F. filiformis mitogenome. The conserved PCG cox3 is located in an intron of another conserved PCG, nad5. This is a unique phenomenon in all known fungal mitogenomes. Gain/loss of introns was observed in cox1, nad5, and rnl. Length polymorphism was widely observed in intergenic regions. Accordingly, primers were designed as useful markers for rapid identification of F. filiformis isolates with differentiated mitogenomes. Our findings provide a basis for further studies related to variety identification and population genetics of this economically important mushroom.

Metabolomics reveals dopa melanin involved in the enzymatic browning of the yellow cultivars of East Asian golden needle mushroom (Flammulina filiformis).

Browning seriously causes postharvest deterioration of the yellow cultivars of Flammulina filiformis, yet the browning process and its mechanism have not been described. Changes of L*, a*, b* values, the browning and whiteness index during air contacted storage were evaluated, uncovering the great loss of brightness and meanwhile the accumulation of yellowness and redness. Browning tissue showed an increase of malondialdehyde, total phenolics, and browning-related enzyme activities of polyphenol oxidase and peroxidase, in contrast to the decrease of bioprotective catalase, superoxide, and dismutase. Non-targeted metabolomics revealed an upregulation of melanin synthesis under oxidation stress, and targeted LC-MS/MS verified the upregulation of l-dopa (3,4-dihydroxy-l-phenylalanine) during browning. Pyrrole-2,3,5-tricarboxylic acid was identified in the degradation products of browning pigments after alkaline hydrogen peroxide by LC-MS/MS, suggesting the existence of 5,6-dihydroxyindole-2-carboxylic acid derived units of eumelanin. Therefore, the biosynthesis of eumelanin via l-dopa pathway could participate in the enzymatic browning of postharvest F. filiformis.

[Study on methods of deproteinization from Phellinus baumii polysaccharide].

OBJECTIVE: To study and compare different methods and influencing factors of deproteinization from Phellinus baumii polysaccharide. METHODS: Sevag method and TCA method were used to remove protein from crude polysaccharide of Phellinus baumii, respectively. RESULTS: The effect of TCA method on removing protein was superior to that of Sevag method,and the optimum conditions of removing protein with TCA were as follows: 30 min treating time, 5% trichloroacetic acid,3 times treatemt. Under these conditions the rate of protein-removed was 82% and the rate of polysaccharide-lost was 10.8%. CONCLUSION: TCA method is the optimal mean for deproteinization from Phellinus baumii polysaccharide.