Potential molecular mechanisms for fruiting body formation of Cordyceps illustrated in the case of Cordyceps sinensis

Metabolite profiling and antioxidant capacity of natural Ophiocordyceps gracilis and its cultures using LC-MS/MS-based metabolomics: Comparison with Ophiocordyceps sinensis

INTRODUCTION

Ophiocordyceps gracilis is an entomopathogenic fungus and a precious traditional Chinese medicine with similar medicinal properties to Ophiocordyceps sinensis. However, information on the metabolite profiles of natural O. gracilis and its cultures is lacking, which limits their utilization.

OBJECTIVE

The metabolic variations and antioxidant activities of O. gracilis cultures and natural O. gracilis were analyzed to evaluate the nutritional and medicinal value of O. gracilis and its cultures.

METHOD

The metabolite profiles of O. gracilis cultures (fruiting bodies and aerial mycelia), natural O. gracilis, and natural O. sinensis were compared by LC-MS/MS coupled with multivariate data analysis. Furthermore, their antioxidant activities were evaluated based on their DPPH• , ABTS•+ , and • OH scavenging abilities.

RESULTS

A total of 612 metabolites were identified, and the metabolic compositions of the four Cordyceps samples were similar, with differences observed in the levels of some metabolites. There were 126 differential metabolites between natural O. gracilis and natural O. sinensis, among which fatty acids, carbohydrates, and secondary metabolites are predominant in natural O. gracilis. Furthermore, 116 differential metabolites between O. gracilis cultures and natural Cordyceps were identified, with generally higher levels in O. gracilis cultures than in natural Cordyceps. O. gracilis cultivated fruiting bodies exhibited the strongest antioxidant capacity among Cordyceps samples. Additionally, 46 primary and 24 secondary differential metabolites contribute to antioxidant activities.

CONCLUSION

This study provides a reference for the application of natural O. gracilis and its cultures in functional food and medicine from the perspective of metabolites and antioxidant capacity.

Unravelling the Transcriptional Response of Agaricus bisporus under Lecanicillium fungicola Infection

Mushrooms are a nutritionally rich and sustainably-produced food with a growing global market. Agaricus bisporus accounts for 11% of the total world mushroom production and it is the dominant species cultivated in Europe. It faces threats from pathogens that cause important production losses, including the mycoparasite Lecanicillium fungicola, the causative agent of dry bubble disease. Through quantitative real-time polymerase chain reaction (qRT-PCR), we determine the impact of L. fungicola infection on the transcription patterns of A. bisporus genes involved in key cellular processes. Notably, genes related to cell division, fruiting body development, and apoptosis exhibit dynamic transcriptional changes in response to infection. Furthermore, A. bisporus infected with L. fungicola were found to accumulate increased levels of reactive oxygen species (ROS). Interestingly, the transcription levels of genes involved in the production and scavenging mechanisms of ROS were also increased, suggesting the involvement of changes to ROS homeostasis in response to L. fungicola infection. These findings identify potential links between enhanced cell proliferation, impaired fruiting body development, and ROS-mediated defence strategies during the A. bisporus (host)-L. fungicola (pathogen) interaction, and offer avenues for innovative disease control strategies and improved understanding of fungal pathogenesis.

Comparative metabolic profiling of mycelia, fermentation broth, spore powder and fruiting bodies of Ophiocordyceps gracilis by LC-MS/MS

INTRODUCTION

Ophiocordyceps gracilis, a type of edible and medicinal fungus, exhibits multiple health-promoting effects. Due to the scarcity of natural O. gracilis, artificial cultures have been developed as its substitutes. However, lacking comprehension of the metabolite composition of cultures limits its utilisation.

OBJECTIVE

This research aimed to evaluate the nutritional and medicinal value of four cultures of O. gracilis by analysing their metabolite composition. In addition, metabolic pathways in mycelia and fruiting bodies were analysed to explore fruiting body formation mechanism at metabolic level.

METHOD

The mycelia, fermentation broth, spore powder and fruiting bodies of O. gracilis were cultivated in this study. Their metabolite composition was compared using an untargeted metabolomics approach based on liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

Principal component analysis (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA) showed that the four cultures have noticeable differences in metabolite composition. A total of 612 metabolites were identified, among which 159 metabolites showed significant differences, and these differential metabolites were classified into 13 categories. The metabolites in the fruiting bodies were the most abundant compared with other cultures. However, each culture had its own advantages and significantly accumulates some active metabolites respectively. Pearson's correlation analysed the mutual relationship among metabolites. In addition, seven metabolic pathways were closely related to fruiting body formation, such as "Biosynthesis of plant secondary metabolites", "amino acids metabolism", "tricarboxylic acid (TCA) cycle".

CONCLUSION

This study offered a reference to mycelia, fermentation broth, spore powder and fruiting bodies of O. gracilis as health-promoting functional foods and medicine.

Unraveling the Secrets of a Double-Life Fungus by Genomics: Ophiocordyceps australis CCMB661 Displays Molecular Machinery for Both Parasitic and Endophytic Lifestyles

Ophiocordyceps australis (Ascomycota, Hypocreales, Ophiocordycipitaceae) is a classic entomopathogenic fungus that parasitizes ants (Hymenoptera, Ponerinae, Ponerini). Nonetheless, according to our results, this fungal species also exhibits a complete set of genes coding for plant cell wall degrading Carbohydrate-Active enZymes (CAZymes), enabling a full endophytic stage and, consequently, its dual ability to both parasitize insects and live inside plant tissue. The main objective of our study was the sequencing and full characterization of the genome of the fungal strain of O. australis (CCMB661) and its predicted secretome. The assembled genome had a total length of 30.31 Mb, N50 of 92.624 bp, GC content of 46.36%, and 8,043 protein-coding genes, 175 of which encoded CAZymes. In addition, the primary genes encoding proteins and critical enzymes during the infection process and those responsible for the host-pathogen interaction have been identified, including proteases (Pr1, Pr4), aminopeptidases, chitinases (Cht2), adhesins, lectins, lipases, and behavioral manipulators, such as enterotoxins, Protein Tyrosine Phosphatases (PTPs), and Glycoside Hydrolases (GHs). Our findings indicate that the presence of genes coding for Mad2 and GHs in O. australis may facilitate the infection process in plants, suggesting interkingdom colonization. Furthermore, our study elucidated the pathogenicity mechanisms for this Ophiocordyceps species, which still is scarcely studied.

Optimization of a solid culture medium based on Monochamus alternatus for Cordyceps militaris fruiting body formation

Monochamus alternatus (Coleoptera: Cerambycidae; M. alternatus), popularly known as the Japanese pine sawyer, is a vector of pinewood nematode (Bursaphelenchus xylophilus) that causes pine wilt disease. A solid medium culture with M. alternatus produced Cordyceps militaris fruiting bodies with the longest strips and the highest biological efficiency. Supplementing the original form of M. alternatus with oats resulted in slightly enhanced fruiting body production. The original form of M. alternatus showed higher production than its powder form. The solid culture medium was optimized using a response surface methodology, and the optimal medium contained the following: 8·5 g per bottle of M. alternatus and 11·5 g per bottle of oats mixed with 22·4 ml of water in a 300-ml cylindrical plastic bottle. The optimal culturing period for the fruiting body formation was 37·1 days. Under these conditions, a fruiting body dry weight of 38·0 g per bottle (actual value) was attained. The fruiting body produced using a solid culture medium based on M. alternatus had a cordycepin content of about 25 µg g^-1 . The solid culture medium containing M. alternatus is highly efficient and eco-friendly, and its effectiveness in large-scale fruiting body production from C. militaris has been demonstrated.

iTRAQ-based comparative proteome analyses of different growth stages revealing the regulatory role of reactive oxygen species in the fruiting body development of Ophiocordyceps sinensis

In this study, using an isobaric tags for relative and absolute quantitation (iTRAQ ) approach coupled with LC-MS / MS and bioinformatics, the proteomes were analyzed for the crucial three stages covering the fruiting body development of Ophiocordyceps sinensis, including sclerotium (ST), primordium (PR) and mature fruiting body (MF), with a focus on fruiting body development-related proteins and the potential mechanisms of the development. A total of 1,875 proteins were identified. Principal Component Analysis (PCA) demonstrated that the protein patterns between PR and MF were more similar than ST. Differentially accumulated proteins (DAPs) analysis showed that there were 510, 173 and 514 DAPs in the comparisons of ST vs. PR, PR vs. MF and ST vs. MF, respectively. A total of 62 shared DAPs were identified and primarily enriched in proteins related to ‘carbon transport and mechanism’, ‘the response to oxidative stress’, ‘antioxidative activity’ and ‘translation’. KEGG and GO databases showed that the DAPs were enriched in terms of ‘primary metabolisms (amino acid/fatty acid/energy metabolism)’, ‘the response to oxidative stress’ and ‘peroxidase’. Furthermore, 34 DAPs involved in reactive oxygen species (ROS) metabolism were identified and clustered across the three stages using hierarchical clustering implemented in hCluster R package . It was suggested that their roles and the underlying mechanisms may be stage-specific. ROS may play a role in fungal pathogenicity in ST, the fruit-body initiation in PR, sexual reproduction and highland adaptation in MF. Crucial ROS-related proteins were identified, such as superoxide dismutase (SOD, T5A6F1), Nor-1 (T5AFX3), electron transport protein (T5AHD1), histidine phosphotransferase (HPt, T5A9Z5) and Glutathione peroxidase (T5A9V1). Besides, the accumulation of ROS at the three stages were assayed using 2,7-dichlorofuorescin diacetate (DCFH-DA) stanning. A much stronger ROS accumulation was detected at the stage MF, compared to the stages of PR and ST. Sections of ST and fruit-body part of MF were stained by DCFH-DA and observed under the fluorescencemicroscope, showing ROS was distributed within the conidiospore and ascus. Besides, SOD activity increased across the three stages, while CAT activity has a strong increasement in MF compared to the stages of ST and PR. It was suggested that ROS may act in gradient-dependent manner to regulate the fruiting body development. The coding region sequences of six DAPs were analyzed at mRNA level by quantitative real-time PCR (qRT-PCR). The results support the result of DAPs analysis and the proteome sequencing data. Our findings offer the perspective of proteome to understand the biology of fruiting body development and highland adaptation in O. sinensis, which would inform the big industry of this valuable fungus.

Quality control method of sterols in fermented Cordyceps sinensis based on combined fingerprint and quantitative analysis of multicomponents by single marker

In this study, we established a new pattern for differentiating and comprehensively evaluating the quality of fermented Cordyceps sinensis based on high-performance liquid chromatography (HPLC) fingerprint analysis combined with similar analysis (SA), principal component analysis (PCA), hierarchical cluster analysis (HCA), and the quantitative analysis of multicomponents by single marker (QAMS). These methods indicated that fermented Cordyceps sinensis samples could be categorized into one class by PCA and HCA. The fingerprints of fermented Cordyceps sinensis were established, and four HPLC peaks were identified as ergosterol, daucosterol, stigmasterol, and β-sitosterol in Jinshuibao capsules and tablets (two products of fermented Cordyceps sinensis). Ergosterol was chosen as the internal reference substance, and the relative correction factors (RCFs) between ergosterol and the other three sterols were calculated using the QAMS method. Moreover, the accuracy of the QAMS method was confirmed by comparing the relative error between the results of the method used with those of an external standard method (ESM). No significant difference between the two methods was observed. The total sterols content in Jinshuibao products were calculated by the QAMS method, and the total sterols content of the two products were similar. This study showed that the method established herein was efficient and successful in the identification fermented Cordyceps sinensis and may further act to facilitate systematic quality control of fermented Cordyceps sinensis products.

Cordycepin, isolated from medicinal fungus Cordyceps sinensis, enhances radiosensitivity of oral cancer associated with modulation of DNA damage repair

Concurrent chemotherapy and radiotherapy (RT) is important for controlling oral squamous cell carcinoma (OSCC), which is often accompanied by significant acute and late toxicities. We investigated whether cordycepin, a small molecule extracted from Cordyceps sinensis, could enhance the radiosensitivity of oral cancer cells. Using colony formation assay, we demonstrated that cordycepin induces radiosensitizing effects on two OSCC cells. DNA histogram analysis showed that cordycepin combined with RT prolonged the RT-induced G2/M phase arrest. It protracted the duration of DNA double strand breaks, which was detected by immunofluorescent staining of phosphorylated histone H2AX (γ-H2AX). The underlying molecular mechanism might involve the downregulation of protein expression related to DNA damage repair, including phosphorylated ataxia-telangiectasia mutated (p-ATM) and phosphorylated checkpoint kinase 2. Reciprocal upregulation of phosphorylated checkpoint kinase 1 (Chk1) expression was noted, and the radiosensitizing effect of cordycepin could be further augmented by Chk1 mRNA knockdown, indicating a compensatory DNA repair machinery involving phosphorylation of Chk1. In vivo, the combination of cordycepin and RT exhibited greater growth inhibition on xenografts and stronger apoptosis induction than RT alone, without exacerbating major toxicities. In conclusion, cordycepin increased the radiosensitivity of OSCC cells, which is associated with the modulation of RT-induced DNA damage repair machinery.