Effects of selenium and light wavelengths on liquid culture of Cordyceps militaris Link

Genomic and Transcriptome Analysis Reveals the Biosynthesis Network of Cordycepin in Cordyceps militaris

Cordycepin is the primary active compound of Cordyceps militaris. However, the definitive genetic mechanism governing cordycepin synthesis in fruiting body growth and development remains elusive, necessitating further investigation. This study consists of 64 C. militaris strains collected from northeast China. The high-yielding cordycepin strain CMS19 was selected for the analysis of cordycepin production and the genetic basis of cordycepin anabolism. First, the whole-genome sequencing of CMS19 yielded a final size of 30.96 Mb with 8 contigs and 9781 protein-coding genes. The genome component revealed the presence of four additional secondary metabolite gene clusters compared with other published genomes, suggesting the potential for the production of new natural products. The analyses of evolutionary and genetic differentiation revealed a close relationship between C. militaris and Beauveria bassiana. The population of strains distributed in northeast China exhibited the significant genetic variation. Finally, functional genes associated with cordycepin synthesis were identified using a combination of genomic and transcriptomic analyses. A large number of functional genes associated with energy and purine metabolism were significantly enriched, facilitating the reconstruction of a hypothetical cordycepin metabolic pathway. Therefore, our speculation of the cordycepin metabolism pathway involved 24 genes initiating from the glycolysis and pentose phosphate pathways, progressing through purine metabolism, and culminating in the core region of cordycepin synthesis. These findings could offer fundamental support for scientific utilizations of C. militaris germplasm resources and standardized cultivation for cordycepin production.

Ethanolic extract from fruiting bodies of Cordyceps militaris HL8 exhibits cytotoxic activities against cancer cells, skin pathogenic yeasts, and postharvest pathogen Penicillium digitatum

Cordyceps militaris is a well-known medicinal mushroom in Asian countries. This edible fungus has been widely exploited for traditional medicine and functional food production. C. militaris is a heterothallic fungus that requires both the mating-type loci, MAT1-1 and MAT1-2, for fruiting body formation. However, recent studies also indicated two groups of C. militaris, including monokaryotic strains carrying only MAT1-1 in their genomes and heterokaryotic strains harboring both MAT1-1 and MAT1-2. These strain groups are able to produce fruiting bodies under suitable cultivating conditions. In previous work, we showed that monokaryotic strains are more stable than heterokaryotic strains in fruiting body formation through successive culturing generations. In this study, we report a high cordycepin-producing monokaryotic C. militaris strain (HL8) collected in Vietnam. This strain could form normal fruiting bodies with high biological efficiency and contain a cordycepin content of 14.43 mg/g lyophilized fruiting body biomass. The ethanol extraction of the HL8 fruiting bodies resulted in a crude extract with a cordycepin content of 69.15 mg/g. Assays of cytotoxic activity on six human cancer cell lines showed that the extract inhibited the growth of all these cell lines with the IC50 values of 6.41-11.51 µg/mL. Notably, the extract significantly reduced cell proliferation and promoted apoptosis of breast cancer cells. Furthermore, the extract also exhibited strong antifungal activity against Malassezia skin yeasts and the citrus postharvest pathogen Penicillium digitatum. Our work provides a promising monokaryotic C. militaris strain as a bioresource for medicine, cosmetics, and fruit preservation.

Evidence for Regulation of Cordycepin Biosynthesis by Transcription Factors Krüppel-Like Factor 4 and Retinoid X Receptor Alpha in Caterpillar Medicinal Mushroom Cordyceps militaris (Ascomycetes)

Cordyceps militaris, Chinese traditional medicinal fungus, has many bioactive properties. Cordycepin (3'-deoxyadenosine) is a major bioactive component of C. militaris. Various methods can significantly elevate cordycepin production, which suggests a diverse set of metabolic regulatory mechanisms. Thus, we aimed to identify transcription factors that regulate cordycepin biosynthesis pathways. Transcriptome analysis of wild-type C. militaris, C. militaris GYS60, a cordycepin high-producing strain, and C. militaris GYS80, a low-producing strain, were used to measure expression and function of genes related to cordycepin biosynthesis. The transcriptome expression data were confirmed by quantitative real-time polymerase chain reaction. We identified 155 relevant transcription factors in 19 families that included Fork head/winged helix factors, other C4 zinc finger-type factors, C2H2 zinc finger factors, tryptophan cluster factors, nuclear receptors with C4 zinc fingers, homeodomain factors, and Rel homology region factors. Energy generation and amino acid conversion pathways were activated in GYS60 so that abundance of cordycepin precursors was increased. Genes and transcription factors for rate-limiting enzymes in these pathways were identified. Overexpression of two key transcription factors, Kruppel-like factor 4 (Klf4) and Retinoid X receptor alpha (Rxra), promoted high cordycepin production in GYS60. In GYS60, Klf4 and Rxra were responsible for upregulation of genes in cordycepin biosynthesis, namely an oxidoreductase, 3',5'-cyclic AMP phosphodiesterase, a transferase, and adenylate cyclase. Upregulation of these genes increased 3'-AMP content, thereby elevating cordycepin synthesis.

Hydrophobin Gene Cmhyd4 Negatively Regulates Fruiting Body Development in Edible Fungi Cordyceps militaris

A deep understanding of the mechanism of fruiting body development is important for mushroom breeding and cultivation. Hydrophobins, small proteins exclusively secreted by fungi, have been proven to regulate the fruiting body development in many macro fungi. In this study, the hydrophobin gene Cmhyd4 was revealed to negatively regulate the fruiting body development in Cordyceps militaris, a famous edible and medicinal mushroom. Neither the overexpression nor the deletion of Cmhyd4 affected the mycelial growth rate, the hydrophobicity of the mycelia and conidia, or the conidial virulence on silkworm pupae. There was also no difference between the micromorphology of the hyphae and conidia in WT and ΔCmhyd4 strains observed by SEM. However, the ΔCmhyd4 strain showed thicker aerial mycelia in darkness and quicker growth rates under abiotic stress than the WT strain. The deletion of Cmhyd4 could promote conidia production and increase the contents of carotenoid and adenosine. The biological efficiency of the fruiting body was remarkably increased in the ΔCmhyd4 strain compared with the WT strain by improving the fruiting body density, not the height. It was indicated that Cmhyd4 played a negative role in fruiting body development. These results revealed that the diverse negative roles and regulatory effects of Cmhyd4 were totally different from those of Cmhyd1 in C. militaris and provided insights into the developmental regulatory mechanism of C. militaris and candidate genes for C. militaris strain breeding.

Transcriptome and metabolome profiling unveils the mechanisms of naphthalene acetic acid in promoting cordycepin synthesis in Cordyceps militaris

Cordycepin, an important active substance in Cordyceps militaris, possesses antiviral and other beneficial activities. In addition, it has been reported to effectively promote the comprehensive treatment of COVID-19 and thus has become a research hotspot. The addition of naphthalene acetic acid (NAA) is known to significantly improve the yield of cordycepin; however, its related molecular mechanism remains unclear. We conducted a preliminary study on C. militaris with different concentrations of NAA. We found that treatment with different concentrations of NAA inhibited the growth of C. militaris, and an increase in its concentration significantly improved the cordycepin content. In addition, we conducted a transcriptome and metabolomics association analysis on C. militaris treated with NAA to understand the relevant metabolic pathway of cordycepin synthesis under NAA treatment and elucidate the relevant regulatory network of cordycepin synthesis. Weighted gene co-expression network analysis (WGCNA), transcriptome, and metabolome association analysis revealed that genes and metabolites encoding cordycepin synthesis in the purine metabolic pathway varied significantly with the concentration of NAA. Finally, we proposed a metabolic pathway by analyzing the relationship between gene-gene and gene-metabolite regulatory networks, including the interaction of cordycepin synthesis key genes; key metabolites; purine metabolism; TCA cycle; pentose phosphate pathway; alanine, aspartate, and glutamate metabolism; and histidine metabolism. In addition, we found the ABC transporter pathway to be significantly enriched. The ABC transporters are known to transport numerous amino acids, such as L-glutamate, and participate in the amino acid metabolism that affects the synthesis of cordycepin. Altogether, multiple channels work together to double the cordycepin yield, thereby providing an important reference for the molecular network relationship between the transcription and metabolism of cordycepin synthesis.

Efficacy of Green Extracting Solvents on Antioxidant, Xanthine Oxidase, and Plant Inhibitory Potentials of Solid-Based Residues (SBRs) of Cordyceps militaris

Solid-based residues (SBRs) of Cordyceps militaris are often considered as waste after the cultivation of the fruiting body. To demonstrate the value of this by-product, different ratios of two favorable green solvents (EtOH and water) were employed to optimize the yields of cordycepin (Cor) and adenosine (Ado) and investigate relevant activities of plant growth inhibition (allelopathy), antioxidants, and xanthine oxidase. The SBR extracts of 60% EtOH-40% water (W4) and 40% EtOH-60% water (W6) exhibited the highest antioxidant activity as well as yielded the optimum content of Cor and Ado. The W4 and Wt (hot water) exhibited maximum inhibitory effects on the growth of Raphanus sativus (radish), Lactuca sativa (lettuce) and two noxious weeds, Echinochloa crus-galli (barnyard grass) and Bidens pilosa (beggarticks). Furthermore, GC-MS scan analysis revealed the presence of 14 major compounds in the SBRs. W4 is the best solvent to optimize yields of Cor and Ado, as well as having the strongest levels of antioxidant activity, xanthine oxidase, and growth-inhibitory activity. This study reveals that SBRs are a potential source of medicinal and agricultural utilization.

The antioxidant potential of different edible and medicinal mushrooms

Mushroom consumption has grown extraordinarily owing to their high nutritional value, desirable taste, and aroma. Mushrooms continue generating lots of interest chiefly in their consumption as food, as a cure for different ailments, as well as important goods for commerce throughout the globe owing to their dietary, antioxidant, and therapeutic values. Higher Ascomycetes and Basidiomycetes mushrooms have different properties with anticancer and immunological potential. They as well provide vital health benefits and display a wide-ranging continuum of pharmacological effects. The antioxidant activity of different mushrooms was reviewed for different radicals including DPPH, ABTS, OH, Nitrite, metals, and lipid peroxidation. The present review presents pharmacological activities of different species of edible and medicinal mushrooms. This review provides tangible evidence that these mushrooms are an excellent source of natural constituents and antioxidants with potential application in pharmaceuticals and in treating and managing different diseases.

Cloning and analysis of the photoreceptor genes Oxwc-1 and Oxwc-2 from ethnopharmacological fungus Ophiocordyceps xuefengensis

Ophiocordyceps xuefengensis is an ethnopharmacological fungus with broad pharmacological properties. Light is a critical environmental factor for the stromata formation and development of many fungi. In this study, photomorphogenesis and blue light receptor genes were studied using a strain of O. xuefengensis. Light represses vegetative growth, but conidia linked to stromata can be observed under both light and dark conditions. Light and dark conditions had little effect on the accumulation of polysaccharides and adenosine. The genes Oxwc-1 and Oxwc-2 encoding photoreceptors of O. xuefengensis were cloned and predicted to possess polypeptides of 937 and 525 amino acids, respectively. A phylogenetic analysis based on fungal WC-1/2 supported OxWC-1 and OxWC-2 were photoreceptor. The expression of both the Oxwc-1 and Oxwc-2 genes reached a maximum after receiving light stimulation for 15 min, which might relate to the inhibition of stromata growth.

Low Dose of Fluoride in the Culture Medium of Cordyceps militaris Promotes Its Growth and Enhances Bioactives with Antioxidant and Anticancer Properties

Cordyceps militaris possesses several compounds with medicinal properties, and is commonly used in traditional Chinese functional food and medicine for a variety of health benefits. Because of its rare occurrence in nature, the market demand for artificial C. militaris is on the rise. Furthermore, efforts to increase its bioactive ingredients have also been considered in research. In this study, we aimed to investigate the effect of fluoride on the growth and enrichment of bioactive compounds in C. militaris. A wide range of potassium fluoride concentrations (0, 0.001, 0.01, 0.1, and 1 mM) were added to the culture media as a source of fluoride during the cultivation of C. militaris fruiting bodies. The contents of fluorine and bioactive substances of the fruiting bodies in normal (NM) and fluorine-supplemented (FM) media were measured and compared. C. militaris raised in the growth medium supplemented with 0.01 mM potassium fluoride led to a 44.86% (1.55 ± 0.14 g/bottle) increase in biomass and a 23.43% (3161.38 ± 35.71 µg/g) increase in total carotenoid content in the fruiting bodies. Furthermore, a remarkable increase in superoxide dismutase-like activity (84.75 U/mg) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (IC₅₀ = 2.59 mg/mL) was recorded. In human cancer cell-based assays, C. militaris raised in FM caused stronger cytotoxicity, apoptosis, and cell cycle arrest in human osteosarcoma cells. These results demonstrated that a low dose of fluoride could stimulate the growth of C. militaris fruiting bodies and enhance the production of bioactive ingredients that possess useful antioxidant and anticancer activities.

Determination of Adenosine and Cordycepin Concentrations in Cordyceps militaris Fruiting Bodies Using Near-Infrared Spectroscopy

Near-infrared (NIRS) spectroscopy, coupled with partial least squares regression, was used to predict adenosine and cordycepin concentrations in fruiting bodies of Cordyceps militaris. The fruiting body samples were prepared in four different sample formats, which were intact fruiting bodies, chopped fruiting bodies, dried powder, and dried crude extract. The actual amount of the adenosine and cordycepin concentrations in fresh fruiting bodies was analyzed by high-performance liquid chromatography. Results showed that the prediction models developed from the chopped samples provided excellent accuracy in both parameters with minimal sample preparation. These optimum models provided a coefficient of determination of prediction, standard error of prediction, bias, and residual predictive deviation, which were respectively 0.95, 16.60 mg kg^-1, -8.57 mg kg^-1, and 5.04 for adenosine prediction, and 0.98, 181.56 mg kg^-1, -1.05 mg kg^-1, and 8.9 for cordycepin prediction. The accuracy and performance of the model were determined by ISO12099:2017(E). It was found that these two equations can be considered to be acceptable at a probability level of 95% confidence. The NIRS technique, therefore, has the potential to be an objective method for determining the adenosine and cordycepin concentrations in C. militaris fruiting bodies.

CmVVD is involved in fruiting body development and carotenoid production and the transcriptional linkage among three blue-light receptors in edible fungus Cordyceps militaris

Fruiting body development and carotenoid production are light-induced in Cordyceps militaris. Our previous studies have shown that two blue-light receptors, CmWC-1 and CmCRY-DASH, regulate fruiting body development and secondary metabolism. However, the photosensory system of C. militaris remains unclear. Here, gene deletion of Cmvvd, coding for another blue-light receptor, resulted in reduced conidiation level and significant promotion of carotenoid content. Cmvvd transcription levels at fruiting body stages were higher than at other stages, and fruiting bodies could not develop normally in ΔCmvvd strains, indicating that Cmvvd might play an important role in fruiting body development. Rhythm loops were not affected in ΔCmvvd strains but were regulated by Cmwc-1, and the expression of the rhythm regulator gene Cmfrq was dependent on CmWC-1. Chromatin immunoprecipitation assay confirmed that Cmvvd is the direct target of CmWC-1 in this fungus. Our results also revealed interdependent transcriptional relationships between Cmwc-1 and Cmvvd, and between Cmwc-1 and Cmcry-DASH. Cmcry-DASH expression was affected by Cmvvd, and the function-loss of Cmcry-DASH might be compensated by the high transcription of Cmvvd. This is the first report of the transcriptional linkage among the three blue-light receptors in edible fungi and will be helpful for studies of multicellular development in this fungus.

Purification and structural characterization of a novel natural pigment: cordycepene from edible and medicinal mushroom Cordyceps militaris

In the present work, a novel cordycepic pigment was successfully isolated and identified from Cordyceps militaris, as well as named as cordycepene (C₁₄H₁₇N₁O₄), according to the long unsaturated conjugated polyene structural characteristic. Cordycepene is sensitive to light, high temperature (≥ 60 °C), and acidic condition (pH ≤ 3), but possesses high stability against metal ions, and under alkaline and neutral conditions. Cordycepene shows a comparable DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging activity at higher concentration (≥ 2 mg/mL) to vitamin C. Cordycepene promotes the growth of HSF (human skin fibroblast cell) after incubation for 72 h, and has an ability to repair the UV light-treated HSF cells. In addition, cordycepene increases the antioxidant activity (SOD, superoxide dismutase; GSH-Px, glutathione peroxidase; CAT, catalase) and decreases MDA (malondialdehyde) level, indicating that cordycepene inhibits the photochemical senescence of HSF by enhancing the antioxidant defense system. The discovery of cordycepene can provide a basis for research on light incubation and the accumulation of yellow pigment (carotenoids) from C. militaris.

Promotion of Metabolite Synthesis in Isaria cicadae, a Dominant Species in the Cicada Flower Microbiota, by Cicada Pupae

Cicada flowers, which are edible and medicinal mushrooms, are the fruiting bodies of Isaria cicadae, a fungus that is parasitic on the larvae of cicada pupae. We hypothesize that host factors might possess stimulatory activity on metabolite synthesis in Isaria cicadae. Here, we first compared the microbial community structures of different wild cicada flowers across geographical regions, compartments, and growth stages via high-throughput sequencing. Isaria cicadae TZC-3, an isolate of the most abundant operational taxonomic unit (OTU6782) in all the fungal communities, was isolated from wild cicada flowers. Furthermore, the effects of cicada pupae on metabolite synthesis in Isaria cicadae TZC-3 were studied in submerged culture. The contents of intercellular polysaccharides, adenosine, N6-(2-hydroxyethyl)-adenosine, free amino acids, and hydrolyzed monosaccharides in the mycelia cultured with cicada pupa powder (4%) were significantly increased as compared with the contents in the control group. This indicates that a cicada pupa can act as an elicitor for metabolite synthesis in Isaria cicadae.

Transcriptional profiling of Auricularia cornea in selenium accumulation

Auricularia cornea is a widely cultivated edible fungus with substantial nutritive value. This study aimed to enrich the multifunctional bionutrient element selenium in A. cornea to improve its quality and explore the accumulation of selenium in the fungus using high-throughput RNA-Seq technology. In general, the treatment group with a 100 µg/g supply of selenium outperformed the other treatment groups in terms of high yield, rich crude polysaccharides and a high total selenium concentration. Additional evidences demonstrated the budding and mature phases were two typical growth stages of A. cornea and were important for the accumulation of selenium. Therefore, the budding and mature phase tissues of A. cornea in the treatment group with a 100 µg/g supply of selenium were used for transcriptome analysis and compared to those of a control group that lacked additional selenium. A total of 2.56 × 105 unigenes from A. cornea transcriptome were assembled and annotated to five frequently used databases including NR, GO, KEGG, eggNOG and SwissProt. GO and KEGG pathway analysis revealed that genes involved in metabolic process and translation were up-expressed at the budding stage in response to selenium supplementation, including amino acid metabolism, lipid metabolism, ribosome. In addition, the differential gene expression patterns of A. cornea suggested that the up-expressed genes were more likely to be detected at the budding stage than at the mature stage. These results provide insights into the transcriptional response of A. cornea to selenium accumulation.

Metabolomic profile and nucleoside composition of Cordyceps nidus sp. nov. (Cordycipitaceae): A new source of active compounds

Cordyceps sensu lato is a genus of arthropod-pathogenic fungi, which have been used traditionally as medicinal in Asia. Within the genus, Ophiocordyceps sinensis is the most coveted and expensive species in China. Nevertheless, harvesting wild specimens has become a challenge given that natural populations of the fungus are decreasing and because large-scale culture of it has not yet been achieved. The worldwide demand for products derived from cultivable fungal species with medicinal properties has increased recently. In this study, we propose a new species, Cordyceps nidus, which parasitizes underground nests of trapdoor spiders. This species is phylogenetically related to Cordyceps militaris, Cordyceps pruinosa, and a sibling species of Cordyceps caloceroides. It is found in tropical rainforests from Bolivia, Brazil, Colombia and Ecuador. We also investigated the medicinal potential of this fungus based on its biochemical properties when grown on four different culture media. The metabolic profile particularly that of nucleosides, in polar and non-polar extracts was determined by UPLC, and then correlated to their antimicrobial activity and total phenolic content. The metabolome showed a high and significant dependency on the substrate used for fungal growth. The mass intensities of nucleosides and derivative compounds were higher in natural culture media in comparison to artificial culture media. Among these compounds, cordycepin was the predominant, showing the potential use of this species as an alternative to O. sinensis. Furthermore, methanol fractions showed antimicrobial activity against gram-positive bacteria, and less than 3.00 mg of gallic acid equivalents per g of dried extract were obtained when assessing its total phenolic content by modified Folin-Ciocalteu method. The presence of polyphenols opens the possibility of further exploring the antioxidant capacity and the conditions that may enhance this characteristic. The metabolic composition and biochemical activity indicate potential use of C. nidus in pharmaceutical applications.

Antithrombotic Effect of Fermented Ophiopogon japonicus in Thrombosis-Induced Rat Models

In this study, the antithrombotic and thrombolytic ability of second fermented extract of Ophiopogon japonicus (FEOJ) was verified in thrombosis-induced rats. Thrombosis was induced by oral administration of 2% carrageenan for 4 weeks. Five experimental groups (n = 9/group) involved in the study were control group, thrombosis group, low-dose FEOJ group (2 mL/kg, low-dose Ophiopogon japonicus [LOJ]), middle-dose FEOJ group (6 mL/kg, medium-dose Ophiopogon japonicus [MOJ]), and high-dose FEOJ group (12 mL/kg, high-dose Ophiopogon japonicus [HOJ]). The clotting time (CT), bleeding time (BT), prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen (FBG) were assessed in blood samples, and histological studies were performed on liver and lung tissues. The results demonstrated delayed CT only in MOJ and HOJ groups and delayed BT in all FEOJ groups compared with those in thrombosis and control groups (P < .05). Similarly, APTT was significantly delayed only in MOJ and HOJ groups, and PT was significantly delayed in all FEOJ groups, compared with those in control and thrombosis groups (P < .05). Although concentrations of FBG were similar in control, thrombosis, and LOJ groups, the tendency for decreased concentration of FBG (statistically nonsignificant) in MOJ and HOJ groups has been observed. Histological examination of livers and lungs revealed that thrombosis was partially improved in FEOJ group compared with the thrombosis group. In conclusion, CT, BT, PT, and APTT were prolonged in FEOJ group more than in control and thrombosis groups, thereby, depicting antithrombotic and thrombolytic effects. However, concentration-dependent effects of FEOJ were more prominent in MOJ and HOJ groups than in the LOJ group.

Optimal conditions for cordycepin production in surface liquid-cultured Cordyceps militaris treated with porcine liver extracts for suppression of oral cancer

Cordycepin is one of the most crucial bioactive compounds produced by Cordyceps militaris and has exhibited antitumor activity in various cancers. However, industrial production of large amounts of cordycepin is difficult. The porcine liver is abundant in proteins, vitamins, and adenosine, and these ingredients may increase cordycepin production and bioconversion during C. militaris fermentation. We observed that porcine liver extracts increased cordycepin production. In addition, air supply (2 h/d) significantly increased the cordycepin level in surface liquid-cultured C. militaris after 14 days. Moreover, blue light light-emitting diode irradiation (16 h/d) increased cordycepin production. These findings indicated that these conditions are suitable for increasing cordycepin production. We used these conditions to obtain water extract from the mycelia of surface liquid-cultured C. militaris (WECM) and evaluated the anti-oral cancer activity of this extract in vitro and in vivo. The results revealed that WECM inhibited the cell viability of SCC-4 oral cancer cells and arrested the cell cycle in the G2/M phase. Oxidative stress and mitochondrial dysfunction (mitochondrial fission) were observed in SCC-4 cells treated with WECM for 12 hours. Furthermore, WECM reduced tumor formation in 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis through the downregulation of proliferating cell nuclear antigen, vascular endothelial growth factor, and c-fos expression. The results indicated that porcine liver extracts irradiated with blue light light-emitting diode and supplied with air can be used as a suitable medium for the growth of mycelia and production of cordycepin, which can be used in the treatment of oral cancer.

The blue-light receptor CmWC-1 mediates fruit body development and secondary metabolism in Cordyceps militaris

Light is an essential factor for pigment formation and fruit body development in Cordyceps militaris, a well-known edible and medicinal fungus. Cmwc-1, a homolog of the blue-light receptor gene white collar-1 (wc-1) in Neurospora crassa, was cloned from the C. militaris genome in our previous study. Here, Cmwc-1 gene inactivation results in thicker aerial hyphae, disordered fruit body development, a significant reduction in conidial formation, and carotenoid and cordycepin production. These characteristics were restored when the ΔCmwc-1 strains were hybridized with wild-type strains of the opposite mating type. A genome-wide expression analysis revealed that there were 1042 light-responsive genes in the wild-type strain and only 458 in the ΔCmwc-1 strain. Among five putative photoreceptors identified, Vivid, cryptochrome-1, and cyclobutane pyrimidine dimer photolyase are strongly induced by light in a Cmwc-1-dependent manner, while phytochrome and cryptochrome-2 were not induced. The transcription factors involved in the fungal light reaction were mainly of the Zn2Cys6 type. CmWC-1 regulates adenylosuccinate synthase, an important enzyme for adenosine de novo synthesis, which could explain the reduction in cordycepin production. Some G protein-coupled receptors that control fungal fruit body formation and the sexual cycle were regulated by CmWC-1, and the cAMP pathway involved in light signal transduction in N. crassa was not critical for the photoreaction in the fungus here. A transcriptional analysis indicated that steroid biosynthesis was more active in the ΔCmwc-1 strain, suggesting that CmWC-1 might switch the vegetative growth state to primordia differentiation by suppressing the expression of related genes.

Direct Biotransformation of Dioscin into Diosgenin in Rhizome of Dioscorea zingiberensis by Penicillium dioscin

Diosgenin is an important precursor for synthesis of more than 200 steroidal hormone medicines. Rhizome of Dioscorea zingiberensis C. H. Wright (RDZ) contained the highest content of diosgenin in Dioscorea plant species. Diosgenin is traditionally extracted by acid hydrolysis from RDZ. However, the acid hydrolysis process produces massive wastewater which caused serious environment pollution. In this study, diosgenin extraction by direct biotransformation with Penicillium dioscin was investigated. The spawn cultivation conditions were optimized as: Czapeks liquid culture medium without sugar and agar (1,000 ml) + 6.0 g dioscin/6.0 g DL, 30 °C, 36 h; solid fermentation of RDZ: mycelia/RDZ of 0.05 g/kg, 30 °C, 50 h; the yield of diosgenin was over 90 %. Spawn cultivation was crucial for the direct biotransformation. In the spawn cultivation, amount and ratio of dioscin/DL were the key factors to promote biotransformation activity of P. dioscin. This biotransformation method was environment-friendly, simple and energy saving, and might be a potential substitute for acid hydrolysis in diosgenin extraction industry.

NMR and GC-MS based metabolic profiling and free-radical scavenging activities of Cordyceps pruinosa mycelia cultivated under different media and light conditions

Variation of metabolic profiles in Cordyceps pruinosa mycelia cultivated under various media and light conditions was investigated using 1H nuclear magnetic resonance (NMR) analysis and gas chromatography mass spectrometry (GC-MS) with multivariate statistical analysis. A total of 71 metabolites were identified (5 alcohols, 21 amino acids, 15 organic acids, 4 purines, 3 pyrimidines, 7 sugars, 11 fatty acids, and 5 other metabolites) by NMR and GC-MS analysis. The mycelia grown in nitrogen media and under dark conditions showed the lowest growth and ergosterol levels, essential to a functional fungal cell membrane; these mycelia, however, had the highest levels of putrescine, which is involved in abiotic stress tolerance. In contrast, mycelia cultivated in sabouraud dextrose agar with yeast extract (SDAY) media and under light conditions contained relatively higher levels of fatty acids, including valeric acid, stearic acid, lignoceric acid, myristic acid, oleic acid, palmitoleic acid, hepadecenoic acid, and linoleic acid. These mycelia also had the highest phenolic content and antioxidant activity, and did not exhibit growth retardation due to enhanced asexual development caused by higher levels of linoleic acid. Therefore, we suggested that a light-enriched environment with SDAY media was more optimal than dark condition for cultivation of C. pruinosa mycelia as biopharmaceutical or nutraceutical resources.

Selenium increases chlorogenic acid, chlorophyll and carotenoids of Lycium chinense leaves

BACKGROUND

Leaves of Lycium chinense L. are widely used in traditional Chinese medicine and as functional food in China and south-east Asia. Polyphenols are important active compounds in leaves of L. chinense L, but their compositions are still not very clear. Selenium has been reported to increase some components of plants. In this study, the composition of polyphenols of L. chinense leaves were analysed, and the effects of selenium on the polyphenols and other components were studied.

RESULTS

The main polyphenols were identified as rutin, chlorogenic acid, quercetin, kaempferol and apigenin-7-O-(6'-O-acetyl) glucose-rhamnose. Chlorogenic acid showed the highest average content of 78.36 g kg⁻¹. Rutin, quercetin and kaempferol were determined at low contents from 3.85 g kg⁻¹ to 7.08 g kg⁻¹. Correlation coefficients between selenium and chlorogenic acid, chlorophyll a, chlorophyll b and carotenoids were: R² = 0.963 (P = 0.002), 0.943 (P = 0.005), 0.957 (P = 0.003) and 0.943 (P = 0.005), respectively. Selenium (0.01-0.05 g kg⁻¹) significantly increased chlorogenic acid, chlorophyll and carotenoids by 200-400% and reduced rutin by 400-900%.

CONCLUSION

L. chinense can be an alternative source of chlorogenic acid. Selenium significantly increased chlorogenic acid, chlorophyll a, chlorophyll b and carotenoids, hence increasing the medicinal value of L. chinense leaves. Rutin, quercetin, kaempferol and apigenin-7-O-(6'-O-acetyl) glucose-rhamnose proved to be not significantly influenced by selenium.

Cordyceps militaris and mycelial fermentation induced apoptosis and autophagy of human glioblastoma cells

This study is the first report that investigated the apoptosis-inducing effects of Cordyceps militaris (CM) and its mycelial fermentation in human glioblastoma cells. Both fractions arrested the GBM8401 cells in the G0/G1 phase, whereas the U-87MG cells were arrested at the G2/M transitional stage. Western blot data suggested that upregulation of p53 and p21 might be involved in the disruption of cell cycle progression. Induction of chromosomal condensation and the appearance of a sub-G1 hypodipoid population further supported the proapoptogenicity, possibly through the activation of caspase-3 and caspase-8, and the downregulation of antiapoptotic Bcl-2 and the upregulation of proapoptotic Bax protein expression. Downregulation of mammalian target of rapamycin and upregulation of Atg5 and LC3 II levels in GBM8401 cells implicated the involvement of autophagy. The signaling profiles with mycelial fermentation treatment indicated that mycelial fermentation triggered rapid phosphorylation of Akt, p38 MAPK, and JNK, but suppressed constitutively high levels of ERK1/2 in GBM8401 cells. Mycelial fermentation treatment only significantly increased p38 MAPK phosphorylation, but decreased constitutively high levels of Akt, ERK1/2, and JNK phosphorylation in U-87MG cells. Pretreatment with PI3K inhibitor wortmannin and MEK1 inhibitor PD98059 prevented the mycelial fermentation-induced cytotoxicity in GBM8401 and U-87MG cells, suggesting the involvement of PI3K/Akt and MEK1 pathways in mycelial fermentation-driven glioblastoma cell apoptosis and autophagy.