Metabolomic profiling reveals biomarkers for diverse flesh colors in jelly fungi (Auricularia cornea).

Auricularia cornea has garnered attention due to its nutrition, culinary applications, and promising commercial prospects. However, there is little information available regarding the metabolic profiling of various colors strains. In this study, 642 metabolites across 64 classes were identified by LC-MS/MS to understand the metabolic variations between white, pink and dark brown strains. Notably, prenol lipids, carboxylic acids and fatty acyls accounted for 46.8 % of the total. Comparative analysis revealed 17 shared differential metabolites (DMs) among them. ACP vs ACW exhibited 17 unique metabolites, including d-arginine and maleic acid, etc. ACP vs ACB showed 5 unique metabolites, with only PS(18:1(9Z)/0:0) demonstrating up-regulation. ACB vs ACW showed 8 unique metabolites, including 4-hydroxymandelic acid and 5'-methylthioadenosine, etc. KEGG enrichment analysis highlighted pathway variations, and MetPA analysis identified key-pathways influencing DMs accumulation in A. cornea. This pioneering metabolomics study offers insights into A. cornea metabolic profiling, potential applications, and guides further research.

Potential inhibitory effect of Auricularia auricula polysaccharide on advanced glycation end-products (AGEs).

In this study, a novel polysaccharide, AAP-2S, was extracted from Auricularia auricula, and the anti-glycosylation effect of AAP-2S and its underlying mechanisms were investigated using an in vitro BSA-fructose model and a cellular model. The results demonstrated the inhibiting formation of advanced glycation end products (AGEs) in vitro by AAP-2S. Concurrently, it attenuated oxidative damage to proteins in the model, preserved protein sulfhydryl groups from oxidation, reduced protein carbonylation, prevented structural alterations in proteins, and decreased the formation of ß-crosslinked structures. Furthermore, AAP-2S demonstrated metal-chelating capabilities. GC-MS/MS-based metabolomics were employed to analyze changes in metabolic profiles induced by AAP-2S in a CML-induced HK-2 cell model. Mechanistic investigations revealed that AAP-2S could mitigate glycosylation and ameliorate cell fibrosis by modulating the RAGE/TGF-ß/NOX4 pathway. This study provides a foundational framework for further exploration of Auricularia auricular polysaccharide as a natural anti-AGEs agent, paving the way for its potential development and application as a food additive.

Intestinal Microbiota and Metabolomics Reveal the Role of Auricularia delicate in Regulating Colitis-Associated Colorectal Cancer.

BACKGROUND: The edible fungus Auricularia delicate (ADe) is commonly employed in traditional medicine for intestinal disorders; however, its inhibitory effect on colitis-associated colorectal cancer (CAC) and the underlying mechanisms remain unexplored. (2) Methods: The inhibitory effect of ADe on CAC was investigated using a mouse model induced by azoxymethane/dextran sulfate sodium. RESULTS: ADe effectively suppressed the growth and number of intestinal tumors in mice. Intestinal microbiota analyses revealed that ADe treatment increased Akkermansia and Parabacteroides while it decreased Clostridium, Turicibacter, Oscillospira, and Desulfovibrio. ADe regulated the levels of 2'-deoxyridine, creatinine, 1-palmitoyl lysophosphatidylcholine, and choline in serum. Furthermore, the levels of these metabolites were associated with the abundance of Oscillospira and Paraacteroides. ADe up-regulated the free fatty acid receptor 2 and ß-Arrestin 2, inhibited the nuclear factor kappa B (NF-κB) pathway, and significantly attenuated the levels of inflammatory cytokines, thereby mitigating the inflammatory in CAC mice. CONCLUSIONS: The protective effect of ADe in CAC mice is associated with the regulation of intestinal microbiota, which leads to the inhibition of NF-kB pathway and regulation of inflammation.

Effects of Auricularia auricula-judae polysaccharide on pasting, gelatinization, rheology, structural properties and in vitro digestibility of kidney bean starch.

Auricularia auricula-judae polysaccharide (AP) has unique molecular structures and multiple bioactivities with excellent gel-forming property and thermal tolerance. However, few researches focus on the interactions between AP and legume starches. In this study, the effects of AP on the pasting, gelatinization, rheology, microstructure, and in vitro digestibility of kidney bean starch (KBST) were evaluated. The pasting, gelling and structural properties of AP-KBST mixtures were characterized by rapid visco analyzer, rheometry, texture analyzer, laser particle analyzer, low-field nuclear magnetic resonance, Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. And an in vitro method was employed to measure the digestibility of AP-KBST composites. The pasting viscosity, swelling degree of starch granules, viscoelasticity, gel strength, cold storage stability and water-retention capacity of KBST were enhanced with increasing AP concentration. The combination of AP and KBST exhibited a higher short-range ordered and a firmer and denser structure than that of KBST alone. Moreover, AP increased the contents of resistant starch and slowly digestible starch, which were positively correlated with the storage modulus and the degree of order, thereby suggesting that the formation of strong and ordered gel network structure by synergistic interactions between AP and KBST was responsible for the reduced starch digestibility.

Removal of Aflatoxin B1 by Edible Mushroom-Forming Fungi and Its Mechanism.

Aflatoxins (AFs) are biologically active toxic metabolites, which are produced by certain toxigenic Aspergillus sp. on agricultural crops. In this study, five edible mushroom-forming fungi were analyzed using high-performance liquid chromatography fluorescence detector (HPLC-FLD) for their ability to remove aflatoxin B1 (AFB1), one of the most potent naturally occurring carcinogens known. Bjerkandera adusta and Auricularia auricular-judae showed the most significant AFB1 removal activities (96.3% and 100%, respectively) among five strains after 14-day incubation. The cell lysate from B. adusta exhibited higher AFB1 removal activity (35%) than the cell-free supernatant (13%) after 1-day incubation and the highest removal activity (80%) after 5-day incubation at 40 °C. In addition, AFB1 analyses using whole cells, cell lysates, and cell debris from B. adusta showed that cell debris had the highest AFB1 removal activity at 5th day (95%). Moreover, exopolysaccharides from B. adusta showed an increasing trend (24-48%) similar to whole cells and cell lysates after 5- day incubation. Our results strongly suggest that AFB1 removal activity by whole cells was mainly due to AFB1 binding onto cell debris during early incubation and partly due to binding onto cell lysates along with exopolysaccharides after saturation of AFB1 binding process onto cell wall components.

Auricularia polytricha ethanol crude extract from sequential maceration induces lipid accumulation and inflammatory suppression in RAW264.7 macrophages.

Auricularia polytricha (AP), an edible mushroom, is continuously being studied due to the medicinal properties. In this study, AP crude extracts from three sequential extraction, starting from hexane (APH), ethanol (APE) and water (APW), were examined for their anti-inflammatory activity and lipid accumulation property in macrophages. APE treatment was found to increase lipid droplet accumulation in both RAW264.7 and LPS-stimulated RAW264.7 cells in a dose dependent manner. Furthermore, nitric oxide production upon LPS stimulation was suppressed on APE pre-treatment. LC-MS analysis was performed to identify the potential bioactive compounds in APE. The PPARγ agonist, 15-Deoxy-Δ12,14-prostaglandin J2-2-glycerol ester (15d-PGJ2-G), was uniquely presented in APE, which was previously described to bind with PPARγ and induces lipid uptake via the upregulation of Cd36. We found that pre-treatment with APE also showed an increase in Cd36 mRNA in RAW264.7 cells, indicating that 15d-PGJ2-G is the potential active compound found in AP. In conclusion, APE exhibited the induction of lipid uptake via CD36, resulting in lipid accumulation.

Renoprotective effects of enzyme-hydrolyzed polysaccharides from Auricularia polytricha on adenine-induced chronic kidney diseases in mice.

The present work was aimed to investigate the protective effects of enzymatic-hydrolyzed Auricularia polytricha polysaccharides (EnAPS) on renal functions. The characterizations were analyzed by physicochemical methods, and the renoprotections were processed in adenine-induced chronic kidney diseases (CKD) models of mice. Animal experiments exhibited that EnAPS showed superior renal-protections contributing to its antioxidant effects of increasing the enzyme activities and decreasing the lipid contents, and anti-inflammatory effects of reducing proinflammatory cytokines than A. polytricha polysaccharides (APS). Besides, the anti-apoptosis effects of EnAPS was proved by down-regulating Bax and Caspase-3 expressions and up-regulating Bcl-2 expressions by molecular biotechnology, and the anti-fibrosis effects was confirmed by histopathological observations of staining. The characterizations indicated that lower molecular weights possibly contributed to the superior renoprotective effects. These results suggested that enzymatic hydrolysis had potential effects in enhancing the bioactivities, and the polysaccharides could be used in the development of functional foods supplement against CKD.

De novo assembly of Auricularia polytricha transcriptome and discovery of genes involved in the degradation of lignocellulose.

Auricularia polytricha belonging to Basidiomycota has the ability to degrade lignocellulose. However, there has been no resource in public databases examining the transcriptome of A. polytricha. In this study, high-throughput sequencing platform BGISEQ-500 was used to generate large amount of transcript sequences from A. polytricha for gene discovery and molecular marker development. A total of 28,102 unigenes were discovered from the assembly of clean reads. In addition, functional categorization of the gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) metabolic pathways revealed several important biological processes. GO annotation analysis presented 47 categories, with the major subcategories being catalytic activity, binding, cellular process, metabolic process, and cell. Among the five functional categories and 21 subcategories of processes discovered from KEGG, global and overview maps, carbohydrate metabolism, transport, and catabolism are the main subcategories. Furthermore, among the unigenes related to lignocellulosic degradation discovered by KEGG pathway enrichment analysis, 2, 5, and 16 unigenes in de novo assembly of A. polytricha transcriptome were found to relate to cellulose, hemicellulose, and lignin degradation, respectively. The study provided valuable information on the degradation of lignocellulose to facilitate research on the degradation mechanism, molecular marker, functional research, gene mapping, and other multigenomic studies of species containing lignocellulose.

Optimization of Fermentation Process and Its Impact on Gene Transcription of Intracellular Polysaccharide Synthesis in the Wood Ear Medicinal Mushroom Auricularia auricula-judae (Agaricomycetes).

To improve the production of mycelial biomass and intracellular polysaccharide (IPS), the culture medium composition and culture condition were respectively optimized by response surface methodology and one-factor-at-a-time methodology. The impact of fermentation process on the transcription of genes involved in IPS synthesis was evaluated using quantitative reverse transcription PCR (qRT-PCR). The yield of biomass and IPS were increased by 150% and 177% under the optimized fermentation process, respectively. Moreover, the optimization of fermentation process significantly increased the transcription of genes involved in IPS synthesis, especially pgm-1, ugp, and pgi. This is the first exploration of gene transcription profile for IPS synthesis of Auricularia auricula-judae under submerged fermentation. These results could provide a potential tool for fermentation process optimization and transcriptional regulation of IPS biosynthesis in A. auricula-judae.

Polysaccharides from Auricularia auricula: Preparation, structural features and biological activities.

Auricularia auricula is a well-known traditional edible fungus with high nutritional and pharmacological values. Polysaccharides are identified as one of the pivotal bioactive constituents of natural extracts of A. auricula. Accumulating evidence has revealed that polysaccharides from A. auricula (AAPs) exhibit diverse biological functions. Hence, a systematic review of research advances and future prospects of AAPs is very necessary for facilitating their better understanding. In this review, we have summarized current knowledge about extraction and purification methods, structural features, biological activities and potential molecular mechanisms of AAPs. Besides, the proposed structure-activity relationships of AAPs have also been highlighted and discussed. This review may provide some valuable insights for further researches regarding AAPs.

Response surface methodology for the fermentation of polysaccharides from Auricularia auricula using Trichoderma viride and their antioxidant activities.

Fermentation technology was used to improve the antioxidant activities of Auricularia auricula polysaccharide (AAP). Response surface methodology (RSM) was used to optimize the fermentation conditions. The effects of 4 independent factors: water content (X1: 40-80%), inoculation amount (X2: 2-20%), temperature (X3: 24-32 °C), and time (X4: 4-6 d) on the biological degradation efficiency were evaluated. The RSM results showed that the optimal fermentation conditions were: X1: 61.7%, X2: 12.4%, X3: 31.0 °C, X4: 5.5 d. Verification tests showed no significant differences between the practical and the predictive values for each response. Under the optimal conditions, the degradation rate was 26.89 ± 0.14%, without significant differences with the predicted value (27.03%). The degradation products were classified to different molecular weight (Mw) polysaccharide fragments using membrane separation technology. The FT-IR analysis and monosaccharide composition analysis of degraded AAP (D-AAP-VI) showed that D-AAP-VI was a furan type polysaccharide, which was different from the total AAP (pyran type). In addition, compared to total AAP, the antioxidant activities in vitro of D-AAP-VI were significantly improved (p < 0.05) and D-AAP-VI showed the strongest antioxidant activity. These results indicated that biological degradation may be a suitable way to improve the antioxidant activities of natural polysaccharides.