Changes of Active Substances in Ganoderma lucidum during Different Growth Periods and Analysis of Their Molecular Mechanism.

Ganoderma lucidum, renowned as an essential edible and medicinal mushroom in China, remains shrouded in limited understanding concerning the intrinsic mechanisms governing the accumulation of active components and potential protein expression across its diverse developmental stages. Accordingly, this study employed a meticulous integration of metabolomics and proteomics techniques to scrutinize the dynamic alterations in metabolite accumulation and protein expression in G. lucidum throughout its growth phases. The metabolomics analysis unveiled elevated levels of triterpenoids, steroids, and polyphenolic compounds during the budding stage (BS) of mushroom growth, with prominent compounds including Diplazium and Ganoderenic acids E, H, and I, alongside key steroids such as cholesterol and 4,4-dimethyl-5alpha-cholesta-8,14,24-trien-3beta-ol. Additionally, nutrients such as polysaccharides, flavonoids, and purines exhibited heightened presence during the maturation stage (FS) of ascospores. Proteomic scrutiny demonstrated the modulation of triterpenoid synthesis by the CYP450, HMGR, HMGS, and ERG protein families, all exhibiting a decline as G. lucidum progressed, except for the ARE family, which displayed an upward trajectory. Therefore, BS is recommended as the best harvesting period for G. lucidum. This investigation contributes novel insights into the holistic exploitation of G. lucidum.

Removal of pharmaceutical compounds and toxicology study in wastewater using Malaysian fungal Ganoderma lucidum.

Elevated usage of pharmaceutical products leads to the accumulation of emerging contaminants in sewage. In the current work, Ganoderma lucidum (GL) was used to remove pharmaceutical compounds (PCs), proposed as a tertiary method in sewage treatment plants (STPs). The PCs consisted of a group of painkillers (ketoprofen, diclofenac, and dexamethasone), psychiatrists (carbamazepine, venlafaxine, and citalopram), beta-blockers (atenolol, metoprolol, and propranolol), and anti-hypertensives (losartan and valsartan). The performance of 800 mL of synthetic water, effluent STP, and hospital wastewater (HWW) was evaluated. Parameters, including treatment time, inoculum volume, and mechanical agitation speed, have been tested. The toxicity of the GL after treatment is being studied based on exposure levels to zebrafish embryos (ZFET) and the morphology of the GL has been observed via Field Emission Scanning Electron Microscopy (FESEM). The findings conclude that GL can reduce PCs from <10% to >90%. Diclofenac and valsartan are the highest (>90%) in the synthetic model, while citalopram and propranolol (>80%) are in the real wastewater. GL effectively removed pollutants in 48 h, 1% of the inoculum volume, and 50 rpm. The ZFET showed GL is non-toxic (LC50 is 209.95 mg/mL). In the morphology observation, pellets GL do not show major differences after treatment, showing potential to be used for a longer treatment time and to be re-useable in the system. GL offers advantages to removing PCs in water due to their non-specific extracellular enzymes that allow for the biodegradation of PCs and indicates a good potential in real-world applications as a favourable alternative treatment.

The impact of continuous cultivation of Ganoderma lucidum on soil nutrients, enzyme activity, and fruiting body metabolites.

To explore the impacts of continuous Ganoderma lucidum cultivation on soil physicochemical factors, soil enzyme activity, and the metabolome of Ganoderma lucidum fruiting bodies, this study conducted two consecutive years of cultivation on the same plot of land. Soil physicochemical factors and enzyme activity were assessed, alongside non-targeted metabolomic analysis of the Ganoderma lucidum fruiting bodies under continuous cultivation. The findings unveiled that in the surface soil layer (0-15 cm), there was a declining trend in organic matter, ammonium nitrogen, available phosphorus, available potassium, pH, polyphenol oxidase, peroxidase, alkaline phosphatase, and sucrase, whereas nitrate nitrogen, electrical conductivity (EC), and salt content exhibited an upward trend. Conversely, in the deeper soil layer (15-30 cm), organic matter, ammonium nitrogen, available potassium, alkaline phosphatase, and sucrase demonstrated a decreasing trend, while nitrate nitrogen, available phosphorus, pH, EC, salt content, polyphenol oxidase, and soil peroxidase showed an increasing trend. Metabolomic analysis of Ganoderma lucidum fruiting bodies distinguished 64 significantly different metabolites between the GCK and GT groups, with 39 components having markedly higher relative contents in GCK and 25 components having significantly lower relative contents in GCK compared to GT. Moreover, among these metabolites, there were more types with higher contents in the fruiting bodies harvested in the first year (GCK) compared to those harvested in the second year (GT), with pronounced differences. KEGG pathway analysis revealed that GCK exhibited more complex metabolic pathways compared to GT. The metabolites of Ganoderma lucidum fruiting bodies were predominantly influenced by soil physicochemical factors and soil enzyme activity. In the surface soil layer (0-15 cm), the metabolome was significantly affected by soil pH, soil organic matter, available phosphorus, and soil alkaline phosphatase, while in the deeper soil layer (15-30 cm), differences in the Ganoderma lucidum metabolome were more influenced by soil alkaline phosphatase, soil catalase, pH, nitrate nitrogen, and soil sucrase.

Bidirectional Solid-State Fermentation of Highland Barley by Edible Fungi to Improve Its Functional Components, Antioxidant Activity and Texture Characteristics.

In food industry, the characteristics of food substrate could be improved through its bidirectional solid-state fermentation (BSF) by fungi, because the functional components were produced during BSF. Six edible fungi were selected for BSF to study their effects on highland barley properties, such as functional components, antioxidant activity, and texture characteristics. After BSF, the triterpenes content in Ganoderma lucidum and Ganoderma leucocontextum samples increased by 76.57 and 205.98%, respectively, and the flavonoids content increased by 62.40% (Phellinus igniarius). Protein content in all tests increased significantly, with a maximal increase of 406.11% (P. igniarius). Proportion of indispensable amino acids increased significantly, with the maximum increase of 28.22%. Lysine content increased largest by 437.34% to 3.310 mg/g (Flammulina velutipes). For antioxidant activity, ABTS radical scavenging activity showed the maximal improvement, with an increase of 1268.95%. Low-field NMR results indicated a changed water status of highland barley after fermentation, which could result in changes in texture characteristics of highland barley. Texture analysis showed that the hardness and chewiness of the fermented product decreased markedly especially in Ganoderma lucidum sample with a decrease of 77.96% and 58.60%, respectively. The decrease indicated a significant improvement in the taste of highland barley. The results showed that BSF is an effective technology to increase the quality of highland barley and provide a new direction for the production of functional foods.

Improving nanochemoimmunotherapy efficacy by boosting "eat-me" signaling and downregulating "don't-eat-me" signaling with Ganoderma lucidum polysaccharide-based drug delivery.

To address the challenges posed by low immunogenicity and immune checkpoints during cancer treatment, we propose an alternative strategy that combines immunogenic cell death (ICD) effects with CD47/SIRPα blockade to reactivate phagocytosis of tumor cells by macrophages with polysaccharide-based drug delivery. In this study, the EGFR inhibitor gefitinib was identified as a novel CD47 modulator, which promoted the translocation of CD47 molecules from the cell membrane to endosomes through the EGFR-Rab5 pathway, leading to reduced cell surface CD47 levels and limiting interaction with SIRPα. Based on this finding, we developed prophagocytic mixed nanodrugs to enhance macrophage phagocytosis by encapsulating ICD inducer doxorubicin and CD47 inhibitor gefitinib with immunostimulatory polysaccharides from Ganoderma lucidum. This approach downregulated cell surface CD47 expression to attenuate "don't-eat-me" signaling, while increasing doxorubicin accumulation in tumors by inhibiting drug-resistance proteins, leading to more exposure of calreticulin and amplifying the "eat-me" signaling. In vivo experiments demonstrated that this approach significantly suppressed intraperitoneal tumor dissemination, reversed doxorubicin-induced weight loss, and effectively induced macrophage polarization, dendritic cell maturation, and CD8+ T cell activation. These findings highlighted the significant potential of our macrophage-centered therapeutic strategy using polysaccharide-based nanocarriers and provided new perspectives for chemoimmunotherapy.

Amelioration of CCl4-induced oxidative stress and hepatotoxicity by Ganoderma lucidum in long evans rats.

Liver disease is a serious health problem affecting people worldwide at an alarming rate. The present study aimed to investigate the protective effects of Ganoderma lucidum against CCl4-induced liver toxicity in rats. The experimental Long Evans rats were divided into five groups, of which four groups were treated with carbon tetrachloride (CCl4). Among the CCl4 treated groups, one of the groups was treated with silymarin and two of them with ethanolic extract of G. lucidum at 100 and 200 mg/Kg body weight. The oxidative stress parameters and endogenous antioxidant enzyme concentrations were assessed by biochemical tests. Liver enzymes ALT, AST, and ALP were determined spectrophotometrically. Histopathological examinations were carried out to assess hepatic tissue damage and fibrosis. Reverse transcription PCR (RT-PCR) was performed to determine the expression of IL-1ß, IL-6, IL-10, TNF-α, and TGF-ß genes. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis revealed that G. lucidum is rich in several phytochemicals including 6-Octadecanoic acid (55.81%), l-( +)-Ascorbic acid 2,6-dihexadecanoate (18.72%), Cis-11-Eicosenamide (5.76%), and Octadecanoic acid (5.26%). Treatment with the G. lucidum extract reduced the elevated ALT, AST, ALP levels, and cellular oxidative stress markers and increased the endogenous antioxidant levels. Histopathology observations revealed that the inflammation, infiltration of immune cells, and aberration of collagen fibers in the hepatocytes were altered by the G. lucidum treatment. The increased expression of inflammatory cytokines TNF-α, TGF-ß, IL-1 ß, and IL-6 were markedly suppressed by G. lucidum extract treatment. G. lucidum also prevented the suppression of protective IL-10 expression by CCl4. This study strongly suggests that G. lucidum extract possesses significant hepatoprotective activity as evidenced by reduced oxidative stress and inflammation mediated by suppression in inflammatory cytokine expression and increased protective IL-10 cytokine expression.

Evaluating the Application Potential of a Recombinant Ganoderma Protein as Bioactive Ingredients in Cosmetics.

The aim of this study was to evaluate the application potential of a recombinant fungal immunomodulatory protein from Ganoderma lucidum (rFIP-glu). First, a recombinant plasmid pPIC9K::FIP-glu-His was transferred into Pichia pastoris for the production of protein. The protein was then to assess its free radical scavenging abilities and the effect on the viability of both human immortalized keratinocytes (HaCaT cells) and mouse B16-F10 melanoma cells (B16 cells) in vitro, followed by the effect on the melanin synthesis of B16 cells. The results of SDS-PAGE and western blot showed that rFIP-glu was successfully expressed. Furtherly, a bioactivity assay in vitro indicated that the scavenging rate of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals reached 84.5% at 6.0 mg/mL (p ≤ 0.0001) of rFIP-glu, showing strong antioxidant activity. Subsequently, a safety evaluation demonstrated that rFIP-glu promoted the proliferation of HaCaT cells, with the cell viability reaching 124.3% at 48 µg/mL (p ≤ 0.01), regarding the cell viability of B16 cells after exposure to rFIP-glu (48 µg/mL) significantly inhibited, to 80.7% (p ≤ 0.01). Besides, rFIP-glu inhibited the melanin synthesis of B16 cells in a dose-dependent manner from 100-1000 µg/mL, and rFIP-glu at 500 µg/mL (p ≤ 0.01) exhibited the highest intracellular melanin amount reduction of 16.8%. Furthermore, a mechanism analysis showed that rFIP-glu inhibited tyrosinase (TYR) activity by up-regulating the expression of the microphthalmia-associated transcription factor (MITF) and down-regulating the gene expression of TYR and tyrosinase-related protein-1 (TYRP-1), thus inhibiting melanin synthesis. The data implied that rFIP-glu had significant antioxidant activity and whitening potency. It should be used as raw materials for cosmeceutical applications.

The anti-hepatocellular carcinoma effects of polysaccharides from Ganoderma lucidum by regulating macrophage polarization via the MAPK/NF-κB signaling pathway.

The response of macrophages to environmental signals demonstrates its heterogeneity and plasticity. After different forms of polarized activation, macrophages reach the M1 or M2 activation state according to their respective environment. Ganoderma lucidum polysaccharide (GLPS) is a major bioactive component of Ganoderma lucidum, a well-known medicinal mushroom. Although the immunomodulatory and anti-tumor effects of GLPS have been proven, GLPS's effect on inhibiting hepatocellular carcinoma (HCC) by regulating macrophage polarization is little known. Our data showed that GLPS notably inhibited the growth of a Hepa1-6 allograft. The expression of M1 marker CD86 was higher in the tumor tissue of the GLPS treatment group than in the control group in vivo. In vitro, the phagocytic activity and NO production of macrophages were increased by GLPS treatment. Moreover, it was discovered that GLPS was able to increase the expression of the M1 phenotype marker CD86, iNOS, and pro-inflammatory cytokines comprising IL-12a, IL-23a, IL-27 and TNF-α, but inhibited macrophage polarization towards the M2 phenotype by decreasing the expression of CD206, Arg-1, and inflammation-related cytokines comprising IL-6 and IL-10. The data suggest that GLPS may regulate macrophage polarization. Mechanistically, GLPS increased the phosphorylation of MEK and ERK. In addition, the phosphorylation of IκBα and P65 was increased by GLPS treatment. These data showed that GLPS can regulate the MAPK/NF-κB signaling pathway responsible for M1 polarization. In a nutshell, our research puts forward a new application of GLPS in anti-HCC treatment by regulating macrophage polarization through activating MAPK/NF-κB signaling.

Potential Anti-Rheumatoid Arthritis Activities and Mechanisms of Ganoderma lucidum Polysaccharides.

Rheumatoid arthritis (RA) is a chronic and autoimmune disease characterized by inflammation, autoimmune dysfunction, and cartilage and bone destruction. In this review, we summarized the available reports on the protective effects of Ganoderma lucidum polysaccharides (GLP) on RA in terms of anti-inflammatory, immunomodulatory, anti-angiogenic and osteoprotective effects. Firstly, GLP inhibits RA synovial fibroblast (RASF) proliferation and migration, modulates pro- and anti-inflammatory cytokines and reduces synovial inflammation. Secondly, GLP regulates the proliferation and differentiation of antigen-presenting cells such as dendritic cells, inhibits phagocytosis by mononuclear macrophages and nature killer (NK) cells and regulates the ratio of M1, M2 and related inflammatory cytokines. In addition, GLP produced activities in balancing humoral and cellular immunity, such as regulating immunoglobulin production, modulating T and B lymphocyte proliferative responses and cytokine release, exhibiting immunomodulatory effects. Thirdly, GLP inhibits angiogenesis through the direct inhibition of vascular endothelial cell proliferation and induction of cell death and the indirect inhibition of vascular endothelial growth factor (VEGF) production in the cells. Finally, GLP can inhibit the production of matrix metalloproteinases and promote osteoblast formation, exerting protective effects on bone and articular cartilage. It is suggested that GLP may be a promising agent for the treatment of RA.

Transcriptome analysis reveals insight into the protective effect of N-acetylcysteine against cadmium toxicity in Ganoderma lucidum (Polyporales: Polyporaceae).

Ganoderma lucidum is widely cultivated and used as traditional medicine in China and other Asian countries. As a member of macrofungi, Ganoderma lucidum is also prone to bioaccumulation of cadmium and other heavy metals in a polluted environment, which affects the growth and production of Ganoderma lucidum, as well as human health. N-Acetyl-L-cysteine (NAC) is considered a general antioxidant and free radical scavenger that is involved in the regulation of various stress responses in plants and animals. However, whether NAC could regulate cadmium stress responses in macrofungi, particularly edible fungi, is still unknown. In this work, we found that the exogenous NAC could alleviate Cd-induced growth inhibition and reduce the cadmium accumulation in Ganoderma lucidum. The application of the NAC cloud also inhibit cadmium-induced H2O2 production in the mycelia. By using transcriptome analysis, 2920 and 1046 differentially expressed unigenes were identified in "Cd100 vs CK" and "NAC_Cd100 vs Cd100," respectively. These differential unigenes were classified into a set of functional categories and pathways, which indicated that various biological pathways may play critical roles in the protective effect of NAC against Cd­induced toxicity in Ganoderma lucidum. Furthermore, it suggested that the ATP-binding cassette transporter, ZIP transporter, heat shock protein, glutathione transferases, and Cytochrome P450 genes contributed to the increased tolerance to cadmium stress after NAC application in Ganoderma lucidum. These results provide new insight into the physiological and molecular response of Ganoderma lucidum to cadmium stress and the protective role of NAC against cadmium toxicity.

GLSP and GLSP-derived triterpenes attenuate atherosclerosis and aortic calcification by stimulating ABCA1/G1-mediated macrophage cholesterol efflux and inactivating RUNX2-mediated VSMC osteogenesis.

Background and Purpose: Atherosclerosis is the main pathophysiological foundation of cardiovascular disease, which was caused by inflammation and lipid metabolism disorder, along with vascular calcification. Aortic calcification leads to reduced plaque stability and eventually causes plaque rupture which leads to cardiovascular events. Presently, the drug to treat aortic calcification remains not to be available. Ganoderma lucidum spore powder (GLSP) is from Ganoderma lucidum which is a Traditional Chinese Medicine with the homology of medicine and food. It has multiple pharmacological effects, but no research on aortic calcification during atherosclerosis was performed. This study investigated the effects of GLSP on atherosclerosis and aortic calcification and revealed the underlying mechanism. Methods: In vivo, 8-week-aged male LDLR-/- mice were fed a high-fat diet to induce atherosclerosis along with aortic calcification. Simultaneously, the mice were treated with GLSP at the first week of HFD feeding to determine the protection against early and advanced atherosclerosis. Subsequently, the mice tissues were collected to evaluate the effects of GLSP on atherosclerosis, and aortic calcification, and to reveal the underlying mechanism. In vitro, we determined the major components of GLSP triterpenes by HPLC, and subsequently assessed the protective effects of these main active components on lipid metabolism, inflammation, and calcification in RAW264.7 and HASMC cells. Results: We observed GLSP attenuated plaque area and aortic calcification in the mice with early and advanced atherosclerosis. GLSP reduced the number of foam cells by improving ABCA1/G1-mediated cholesterol efflux in macrophages. In addition, GLSP protected against the aortic endothelium activation. Moreover, GLSP inhibited aortic calcification by inactivating RUNX2-mediated osteogenesis in HASMCs. Furthermore, we determined the major components of GLSP triterpenes, including Ganoderic acid A, Ganoderic acid B, Ganoderic acid C6, Ganoderic acid G, and Ganodermanontriol, and found that these triterpenes promoted ABCA1/G1-mediated cholesterol efflux and inhibited inflammation in macrophage, and inactivated RUNX2-mediated osteogenesis in VSMC. Conclusions: This study demonstrates that GLSP attenuates atherosclerosis and aortic calcification by improving ABCA1/G1-mediated cholesterol efflux and inactivating RUNX2-mediated osteogenesis in LDLR-/- mice. GLSP may be a potential drug candidate for the treatment of atherosclerosis and vascular calcification.

Therapeutic potential and nutritional significance of Ganoderma lucidum - a comprehensive review from 2010 to 2022.

With a long history in traditional Asian medicine, Ganoderma lucidum (G. lucidum) is a mushroom species suggested to improve health and extend life. Its medicinal reputation has merited it with numerous attributes and titles, and it is evidenced to be effective in the prevention and treatment of various metabolic disorders owing to its unique source of bioactive metabolites, primarily polysaccharides, triterpenoids, and polyphenols, attributed with antioxidant, anti-inflammatory, anticancer, hepatoprotective, antidiabetic activities, etc. These unique potential pharmaceutical properties have led to its demand as an important resource of nutrient supplements in the food industry. It is reported that the variety of therapeutic/pharmacological properties was mainly due to its extensive prebiotic and immunomodulatory functions. All literature summarized in this study was collated based on a systematic review of electronic libraries (PubMed, Scopus databases, Web of Science Core Collection, and Google Scholar) from 2010-2022. This review presents an updated and comprehensive summary of the studies on the immunomodulatory therapies and nutritional significance of G. lucidum, with the focus on recent advances in defining its immunobiological mechanisms and the possible applications in the food and pharmaceutical industries for the prevention and management of chronic diseases. In addition, toxicological evidence and the adoption of standard pharmaceutical methods for the safety assessment, quality assurance, and efficacy testing of G. lucidum-derived compounds will be the gateway to bringing them into health establishments.

EFFECT OF DRY EXTRACT FROM REISHI MUSHROOMS ON THE STATE OF ANTIOXIDANT SYSTEM IN RATS WITH DMH-INDUCED COLON CARCINOGENESIS.

OBJECTIVE: The aim: To study pro- and antioxidant systems indicators in rats with chemically induced colon carcinogenesis on the background of the reishi mushrooms dry extract use. PATIENTS AND METHODS: Materials and methods: The study was performed on 120 white male rats. Chronic oncogenic intoxication was modeled by administering 1,2-dimethyl¬hydrazine (DMH) hydrochloride for 30 weeks (1 time per week). A dry extract from the reishi mushrooms was administered intragastrically daily at a dose of 100 mg/kg of the animal's body weight. Blood and liver samples were taken for research monthly. The state of the pro- and antioxidant systems was studied by the content of oxidative modification of proteins products, superoxide dismutase and catalase activity, contents of reduced glutathione and ceruloplasmin. RESULTS: Results: An increase in the activity of free radical oxidation processes after DMH-induced colon carcinogenesis in rats is evidenced by a decrease in the super-oxide dismutase activity, catalase activity, content of reduced glutathione, an increase in the content of ceruloplasmin and products of oxidative modification of proteins in the blood serum and liver of animals. The effectiveness of the dry extract of reishi mushrooms and its positive effect on the state of pro- and antioxidant systems was experimentally proved. CONCLUSION: Conclusions: The use of the dry extract of reishi mushrooms under conditions of DMH-induced colon carcinogenesis in rats led to normalization of the anti¬oxidant protection system state and the reduction of oxidative stress.

Regulation of Nrf2 and Nrf2-related proteins by ganoderma lucidum in hepatocellular carcinoma.

BACKGROUND: HCC is among the most common cancer. Ganoderma lucidum (G.lucidum) has been essential in preventing and treating cancer. The Nrf2 signaling cascade is a cell protective mechanism against further damage, such as cancer development. This signaling pathway upregulates the cytoprotective genes and is vital in eliminating xenobiotics and reactive oxygen. This study aimed to show the potential cytotoxic activity of G. lucidum aqueous extract in HCC. METHODS AND RESULTS: MTT assay was used to detect cell viability. Nrf2-related proteins were measured by western blotting, and the flow cytometry method assayed cell population in different cycle phases. Cell viability was 49% and 47% following G. lucidum extract at 100 µg/ml at 24 and 48 h treatments, respectively. G. lucidum extract (aqueous, 100 or 50 µg/ml) treatments for 24, 48, or 72 h were able to significantly change the cytoplasmic/nuclear amount of Nrf2 and HO-1, NQO1 protein levels. Moreover, at both concentrations, arrest of the G0/G1 cell cycle was stimulated in HCC. CONCLUSIONS: The activation of the Nrf2 signaling pathways seems to be among the mechanisms underlining the protective and therapeutic action of G. lucidum against HCC.

Biosynthesis, Gene Expression, and Pharmacological Properties of Triterpenoids of Ganoderma Species (Agaricomycetes): A Review.

For more than 6 millennia, Ganoderma species have been used in traditional Asian medicine due to their health benefits. Ganoderma synthesizes several compounds with biological activity, including lanostane-type triterpenoids like ganoderic acids (GAs), lucidones, and colosolactones. These triterpenoids have been investigated for their antiviral, hypoglycemic, and anticancer effects. GAs are highly oxygenated triterpenoids with different functional groups attached to lanostane skeleton. Their great chemical diversity makes GAs prospects for the development of new drugs to treat multiple illnesses such as cancer. The effect of GAs against cancer cells has been associated with their capability to inhibit specific targets such as STAT3, to induce apoptosis and cell cycle blockage, and to increase natural killer cell activity. Due to the biological activity of these molecules, novel strategies are being developed for Ganoderma production mainly by liquid cultivation, gene overexpression (HMGR, SQS, LS) by elicitors, and modified growing conditions (carbon and nitrogen sources, pH, temperature), which induce reactive oxygen species production, key compounds for secondary metabolism. In addition, some transcription factors are mainly expressed under stress conditions, such as cytochrome P450 genes, which participate in the regulation of triterpenoid synthesis. The fermentation process has been scaled up to a 300-L bioreactor, which shows good GA production. This article reviews current knowledge on bioactive triterpenoids of Ganoderma and their production, biosynthesis, and pharmacological properties, emphasizing gene expression in liquid culture. It also discusses the lack of information regarding other species with high potential.

GSNOR regulates ganoderic acid content in Ganoderma lucidum under heat stress through S-nitrosylation of catalase.

As a master regulator of the balance between NO signaling and protein S-nitrosylation, S-nitrosoglutathione (GSNO) reductase (GSNOR) is involved in various developmental processes and stress responses. However, the proteins and specific sites that can be S-nitrosylated, especially in microorganisms, and the physiological functions of S-nitrosylated proteins remain unclear. Herein, we show that the ganoderic acid (GA) content in GSNOR-silenced (GSNORi) strains is significantly lower (by 25%) than in wild type (WT) under heat stress (HS). Additionally, silencing GSNOR results in an 80% increase in catalase (CAT) activity, which consequently decreases GA accumulation via inhibition of ROS signaling. The mechanism of GSNOR-mediated control of CAT activity may be via protein S-nitrosylation. In support of this possibility, we show that CAT is S-nitrosylated (as shown via recombinant protein in vitro and via GSNORi strains in vivo). Additionally, Cys (cysteine) 401, Cys642 and Cys653 in CAT are S-nitrosylation sites (assayed via mass spectrometry analysis), and Cys401 may play a pivotal role in CAT activity. These findings indicate a mechanism by which GSNOR responds to stress and regulates secondary metabolite content through protein S-nitrosylation. Our results also define a new S-nitrosylation site and the function of an S-nitrosylated protein regulated by GSNOR in microorganisms.

Heme oxygenase-1/carbon monoxide signaling participates in the accumulation of triterpenoids of Ganoderma lucidum.

Ganoderic triterpenoids (GTs) are the primary bioactive constituents of the Basidiomycotina fungus, Ganoderma lucidum. These compounds exhibit antitumor, anti-hyperlipidemic, and immune-modulatory pharmacological activities. This study focused on GT accumulation in mycelia of G. lucidum mediated by the heme oxygenase-1 (HO-1)/carbon monoxide (CO) signaling. Compared with the control, hemin (10 µmol/L) induced an increase of 60.1% in GT content and 57.1% in HO-1 activity. Moreover, carbon monoxide-releasing molecule-2 (CORM-2), CO donor, increased GT content by 56.0% and HO-1 activity by 18.1%. Zn protoporphyrin IX (ZnPPIX), a specific HO-1 inhibitor, significantly reduced GT content by 26.0% and HO-1 activity by 15.8%, while hemin supplementation reversed these effects. Transcriptome sequencing showed that HO-1/CO could function directly as a regulator involved in promoting GT accumulation by regulating gene expression in the mevalonate pathway, and modulating the reactive oxygen species (ROS) and Ca2+ pathways. The results of this study may help enhance large-scale GT production and support further exploration of GT metabolic networks and relevant signaling cross-talk.

GCN4 Regulates Secondary Metabolism through Activation of Antioxidant Gene Expression under Nitrogen Limitation Conditions in Ganoderma lucidum.

Nitrogen limitation has been widely reported to affect the growth and development of fungi, and the transcription factor GCN4 (general control nonderepressible 4) is involved in nitrogen restriction. Here, we found that nitrogen limitation highly induced the expression of GCN4 and promoted the synthesis of ganoderic acid (GA), an important secondary metabolite in Ganoderma lucidum. The activated GCN4 is involved in regulating GA biosynthesis. In addition, the accumulation of reactive oxygen species (ROS) also affects the synthesis of GA under nitrogen restrictions. The silencing of the gcn4 gene led to further accumulation of ROS and increased the content of GA. Further studies found that GCN4 activated the transcription of antioxidant enzyme biosynthesis genes gr, gst2, and cat3 (encoding glutathione reductase, glutathione S-transferase, and catalase, respectively) through direct binding to the promoter of these genes to reduce the ROS accumulation. In conclusion, our study found that GCN4 directly interacts with the ROS signaling pathway to negatively regulate GA biosynthesis under nitrogen-limiting conditions. This provides an essential insight into the understanding of GCN4 transcriptional regulation of the ROS signaling pathway and enriches the knowledge of nitrogen regulation mechanisms in fungal secondary metabolism of G. lucidum.IMPORTANCE Nitrogen has been widely reported to regulate secondary metabolism in fungi. Our study assessed the specific nitrogen regulatory mechanisms in Ganoderma lucidum. We found that GCN4 directly interacts with the ROS signaling pathway to negatively regulate GA biosynthesis under nitrogen-limiting conditions. Our research highlights a novel insight that GCN4, the nitrogen utilization regulator, participates in secondary metabolism through ROS signal regulation. In addition, this also provides a theoretical foundation for exploring the regulation of other physiological processes by GCN4 through ROS in fungi.

Comparative Study on Bioactivities from Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes), Gives an Insight into the Fermentation Broth Showing Greater Antioxidative Activities.

Ganoderma lucidum is one of the most famous mushrooms in traditional Chinese medicine. At present, the fully utilized parts of G. lucidum are mainly fruiting body and spore powder. The wild and artificially cultivated G. lucidum fruiting body is costly and rare. Therefore, how to improve the utilization of G. lucidum by means of fermentation is worth investigating. The present study was to perform submerged fermentation of G. lucidum and compare the bioactivities of G. lucidum submerged fermentation broth and fruiting body extract. After the extraction and submerged fermentation methods were optimized, the optimum conditions for extraction were determined as ethanol extraction at 80°C with a solid-to-liquid ratio of 1:30, and those for submerged fermentation were cultivation on malt extract medium for 6 days at 30°C. Under the optimum conditions, the antioxidative activity and tyrosinase inhibition rate of the fermentation broth were 1.2-4.1 fold higher than those of the ethanol extract. Cytotoxicity analysis showed that the ethanol and water extracts and the fermentation broth effectively inhibited pancreatic cancer cells and prostate cancer cells, with much smaller effect on nontumor human embryonic kidney (HEK293T). These results demonstrate that the submerged fermentation could improve the utilization value of G. lucidum and the fermentation broth can be used as an antioxidant additive applied in food, drugs, and cosmetics.

Enhanced Ganoderic Acids Accumulation and Transcriptional Responses of Biosynthetic Genes in Ganoderma lucidum Fruiting Bodies by Elicitation Supplementation.

Ganoderic acids (GAs) are a type of highly oxygenated lanostane-type triterpenoids that are responsible for the pharmacological activities of Ganoderma lucidum. They have been investigated for their biological activities, including antibacterial, antiviral, antitumor, anti-HIV-1, antioxidation, and cholesterol reduction functions. Inducer supplementation is viewed as a promising technology for the production of GAs. This study found that supplementation with sodium acetate (4 mM) significantly increased the GAs content of fruiting bodies by 28.63% compared to the control. In order to explore the mechanism of ganoderic acid accumulation, the transcriptional responses of key GAs biosynthetic genes, including the acetyl coenzyme A synthase gene, and the expression levels of genes involved in calcineurin signaling and acetyl-CoA content have been analyzed. The results showed that the expression of three key GAs biosynthetic genes (hmgs, fps, and sqs) were significantly up-regulated. Analysis indicated that the acetate ion increased the expression of genes related to acetic acid assimilation and increased GAs biosynthesis, thereby resulting in the accumulation of GAs. Further investigation of the expression levels of genes involved in calcineurin signaling revealed that Na+ supplementation and the consequent exchange of Na+/Ca2+ induced GAs biosynthesis. Overall, this study indicates a feasible new approach of utilizing sodium acetate elicitation for the enhanced production of valuable GAs content in G. lucidum, and also provided the primary mechanism of GAs accumulation.