Production of ganoderic acid by Ganoderma lucidum RCKB-2010 and its therapeutic potential

Anti-Staphylococcus aureus potential of compounds from Ganoderma sp.: A comprehensive molecular docking and simulation approaches

In this study, a series of secondary metabolites from Ganoderma sp. were screened against Staphylococcus aureus protein targets, including as phosphotransacetylase, clumping factor A, and dihydrofolate reductase, using molecular docking simulations. The chemicals that showed the strongest binding energy with the targeted proteins were ganodermanontriol, lucidumol B, ganoderic acid J, ergosterol, ergosterol peroxide, 7-oxoganoderic acid Z, ganoderic acid AM1, ganosinoside A, ganoderic acid D, and 24R-ergosta-7,2E-diene-3β,5α,6β-triol. Interestingly, ganosinoside A showed the greatest affinity for the protein clumping factor A, a result validated by molecular dynamic simulation. Additionally, three natural Ganoderma sp. Strains as Ganoderma lingzhi VNKKK1903, Ganoderma lingzhi VNKK1905A2, and Amauroderma subresinosum VNKKK1904 were collected from Kon Ka Kinh National Park in central land of Vietnam and evaluated for their antibacterial activity against Staphylococcus aureus using an agar well diffusion technique. These results suggest that the fungal extracts and secondary metabolites may serve as valuable sources of antibiotics against Staphylococcus aureus. These findings provided an important scientific groundwork for further exploration of the antibacterial mechanisms of compounds derived from Ganoderma sp. in future research.

Biologically active secondary metabolites from white-rot fungi

In recent years, there has been a considerable rise in the production of novel metabolites derived from fungi compared to the ones originating from bacteria. These organic substances are utilized in various sectors such as farming, healthcare, and pharmaceutical. Since all dividing living cells contain primary metabolites, secondary metabolites are synthesized by utilizing intermediate compounds or by-products generated from the primary metabolic pathways. Secondary metabolites are not critical for the growth and development of an organism; however, they exhibit a variety of distinct biological characteristics. White-rot fungi are the only microorganisms able to decompose all wood components. Hence, they play an important role in both the carbon and nitrogen cycles by decomposing non-living organic substrates. They are ubiquitous in nature, particularly in hardwood (e.g., birch and aspen) forests. White-rot fungi, besides ligninolytic enzymes, produce different bioactive substances during their secondary metabolism including some compounds with antimicrobial and anticancer properties. Such properties could be of potential interest for the pharmaceutical industries. Considering the importance of the untapped biologically active secondary metabolites from white-rot fungi, the present paper reviews the secondary metabolites produced by white-rot fungi with different interesting bioactivities.

Increasing the production of the bioactive compounds in medicinal mushrooms: an omics perspective

Macroscopic fungi, mainly higher basidiomycetes and some ascomycetes, are considered medicinal mushrooms and have long been used in different areas due to their pharmaceutically/nutritionally valuable bioactive compounds. However, the low production of these bioactive metabolites considerably limits the utilization of medicinal mushrooms both in commerce and clinical trials. As a result, many attempts, ranging from conventional methods to novel approaches, have been made to improve their production. The novel strategies include conducting omics investigations, constructing genome-scale metabolic models, and metabolic engineering. So far, genomics and the combined use of different omics studies are the most utilized omics analyses in medicinal mushroom research (both with 31% contribution), while metabolomics (with 4% contribution) is the least. This article is the first attempt for reviewing omics investigations in medicinal mushrooms with the ultimate aim of bioactive compound overproduction. In this regard, the role of these studies and systems biology in elucidating biosynthetic pathways of bioactive compounds and their contribution to metabolic engineering will be highlighted. Also, limitations of omics investigations and strategies for overcoming them will be provided in order to facilitate the overproduction of valuable bioactive metabolites in these valuable organisms.

A Review of Ganoderma Triterpenoids and Their Bioactivities

For centuries, Ganoderma has been used as a traditional medicine in Asian countries to prevent and treat various diseases. Numerous publications are stating that Ganoderma species have a variety of beneficial medicinal properties, and investigations on different metabolic regulations of Ganoderma species, extracts or isolated compounds have been performed both in vitro and in vivo. However, it has frequently been questioned whether Ganoderma is simply a dietary supplement for health or just a useful "medication" for restorative purposes. More than 600 chemical compounds including alkaloids, meroterpenoids, nucleobases, nucleosides, polysaccharides, proteins, steroids and triterpenes were extracted and identified from Ganoderma, with triterpenes serving as the primary components. In recent years, Ganoderma triterpenes and other small molecular constituents have aroused the interest of chemists and pharmacologists. Meanwhile, considering the significance of the triterpene constituents in the development of new drugs, this review describes 495 compounds from 25 Ganoderma species published between 1984 and 2022, commenting on their source, biosynthetic pathway, identification, biological activities and biosynthesis, together with applications of advanced analytical techniques to the characterization of Ganoderma triterpenoids.

Antiproliferative and antibacterial activity of extracts of Ganoderma strains grown in vitro

In this bioprospecting study the biological activities of extracts of the in vitro culture of Ganoderma Mexican strains were evaluated. The extracts were tested by the Sulforhodamine B staining method for antiproliferative activity and the plate microdilution method for antibacterial activity. Extracts that proved bioactive in these two activities, the antioxidant activity (Galvinoxyl, ABTS, and DPPH) and total phenolic contents (Folin-Ciocalteu) were additionally determined, as well as acute toxicity (Artemia franciscana). In the antiproliferative activity Ganoderma curtisii strain (GH-16-015) obtained a remarkable value of GI50 ≤ 50 µg/mL against tumor lines: A549, HBL-100, HeLa, and T-47D. G. curtisii strains (GH-16-012 and GH-16-015) showed MIC values = 500 µg/mL against Staphylococcus aureus. G. curtisii strain (GH-16-012) almost reduced by 50% the radical Galvinoxyl. Finally, G. curtisii strain (GH-16-023) presented the lowest level of toxicity with a LC50 of 490.881 µg/mL against A. franciscana. These results support the potential medicinal effects of Mexican strains of G. curtisii.

Antibacterial Compounds from Mushrooms: A Lead to Fight ESKAPEE Pathogenic Bacteria?

Infectious diseases are among the greatest threats to global health in the 21st century, and one critical concern is due to antibiotic resistance developed by an increasing number of bacterial strains. New resistance mechanisms are emerging with many infections becoming more and more difficult if not impossible to treat. This growing phenomenon not only is associated with increased mortality but also with longer hospital stays and higher medical costs. For these reasons, there is an urgent need to find new antibiotics targeting pathogenic microorganisms such as ESKAPEE bacteria. Most of currently approved antibiotics are derived from microorganisms, but higher fungi could constitute an alternative and remarkable reservoir of anti-infectious compounds. For instance, pleuromutilins constitute the first class of antibiotics derived from mushrooms. However, macromycetes still represent a largely unexplored source. Publications reporting the antibacterial potential of mushroom extracts are emerging, but few purified compounds have been evaluated for their bioactivity on pathogenic bacterial strains. Therefore, the aim of this review is to compile up-to-date data about natural products isolated from fruiting body fungi, which significantly inhibit the growth of ESKAPEE pathogenic bacteria. When available, data regarding modes of action and cytotoxicity, mandatory when considering a possible drug development, have been discussed in order to highlight the most promising compounds.

Flexible Fungal Materials: Shaping the Future

Fungi are a revolutionary, smart, and sustainable manufacturing platform that can be used to upcycle byproducts and wastes into flexible fungal materials (FFMs) such as chitin- and β-glucan-based foams, paper, and textiles. With highly adaptable manufacturing pathways, the efficiency and properties of these materials depend on the biomass source and fermentation method. Liquid substrates provide fast, upscalable, and compact production processes but are susceptible to contamination and are limited to paper-like materials for printing, wound dressings, and membranes. Solid-state fermentation is cheaper but struggles to deliver homogeneous fungal growth and is used to produce fungal foams for packaging, insulation, textiles, and leather substitutes. The broad range of applications and uses of biological organisms in materials hallmarks fungi as forerunners in improving environmental sustainability globally.

Enhancement of ganoderic acid production by promoting sporulation in a liquid static culture of Ganoderma species

Ganoderic acids (GAs) produced by Ganoderma are a type of lanostane-type triterpenoids with anticancer and antimetastatic activities; however, low production of GAs limits its wide application. In this study, a novel strategy by promoting sporulation of Ganoderma was developed to increase GA production. First, a high-spore producing Ganoderma strain G. 260125 was obtained from dikaryotic strain CGMCC 5.0026, and the sporulation-specific gene of this strain exhibits a higher transcription level than CGMCC 5.0026. Then, the effect of promoting sporulation on GA content was investigated. The maximum ganoderic acid (GA)-T, GA-Mk, and GA-Me contents in G. 260125 in shake flasks were 358.97, 78.32, and 12.75 μg/100 mg dry weight, respectively, which were 3.42, 2.91, and 1.73 times higher than those obtained in CGMCC 5.0026. Moreover, total and individual GA contents in spores were significantly higher than those in liquid static culture. Both concentrations of intermediates and transcription levels of GA biosynthetic genes also improved in G. 260125 during fermentation compared with those in CGMCC 5.0026. For scaling-up experiments, GA-T, GA-Me, and GA-Mk production in G. 260125 improved by 2.2-, 2.6-, and 2.1-fold compared with those in CGMCC 5.0026. In addition, the effectiveness of the developed strategy was also confirmed in three different Ganoderma strains. This work illustrated that promoting sporulation efficiently improves GA production in liquid static cultures of Ganoderma.

Function of ceramide synthases on growth, ganoderic acid biosynthesis and sphingolipid homeostasis in Ganoderma lucidum

Ceramide synthases (CERSs) catalyse an N-acyltransferase reaction using long-chain base (LCB) and fatty acyl-coenzyme A (CoA) as substrates to synthesize ceramide (Cer), which is the backbone of all complex sphingolipids. In the present study, three CERSs (LAG1, LAG2 and LAG3) form Ganoderma lucidum were analysed. The silencing of lag1 by RNA interference reduced ganoderic acid biosynthesis and Cer and complex sphingolipids contents, which contain long-chain-fatty-acids (LCFAs, including C16 and C18). In contrast, the silencing of lag2 or lag3 did not result in obvious phenotypic and sphingolipid homeostasis changes, although the lag2/lag3 double-silenced mutants exhibited increased ganoderic acid biosynthesis as well as reduced growth, reduced Cer and complex sphingolipids contents, which contain very-long-chain fatty acids (VLCFAs, including C22, C24 and C26). The results of the present study indicate that the three assayed CERSs have distinct physiological functions and substrate specificities in G. lucidum.

Enhanced production of individual ganoderic acids by integrating Vitreoscilla haemoglobin expression and calcium ion induction in liquid static cultures of Ganoderma lingzhi

Ganoderic acids produced by Ganoderma exhibit anticancer and antimetastatic activities. A novel approach by combining Vitreoscilla haemoglobin (VHb) expression and calcium ion induction was developed to enhance ganoderic acid (GA) production in liquid static cultures of G. lingzhi. The maximum contents of GA-O, GA-S and GA-Me were 1451.33 ± 67.50, 1431.23 ± 79.74 and 1283.81 ± 85.13 μg per 100 mg cell weight, respectively under the integrated approach, which are the highest contents as ever reported in Ganoderma. The contents of squalene and lanosterol were increased by 2.0- and 3.0-fold in this case compared with those in the control. The transcription levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase, farnesyl-diphosphate synthase, squalene synthase and cytochrome P450 CYP5150L8 were upregulated by 2.56-, 3.31-, 2.59- and 6.12-fold respectively. Additionally, the expression of VHb improved the ratio of type I to type II GA in liquid static cultivation of G. lingzhi. The transcription levels of cyp512a2, cyp512v2 and cyp512a13, candidate cytochrome P450 genes involved in oxidative modification of the lanostane skeleton in GA biosynthesis, were also increased by 2.28-, 2.65- and 3.54-fold in the VHb-expressing strain respectively. Our results illustrated that the approach described here efficiently improved GA production in G. lingzhi fermentation.

Optimization of submerged culture conditions involving a developed fine powder solid seed for exopolysaccharide production by the medicinal mushroom Ganoderma lucidum

To facilitate Ganoderma lucidum submerged cultivation and achieve high productivity, four fine powder solid substrates incorporated with different nitrogen-rich supplements were utilized to grow the fungus and as solid seed for its submerged culture. Of the four solid seeds, the soybean meal solid seed gave the highest biomass (10.73 g/L) and exopolysaccharide (EPS) (1.22 g/L), higher than those (8.36 g/L biomass and 0.44 g/L EPS) obtained with mycelial liquid seed. The optimal level of soybean meal supplementation was 20% (w/w) for production of the solid seed. Following single factor experiments, levels of three selected process variables were optimized as: the moisture content of solid seed, 70%; inoculum size, 0.8 g/flask; and rotary speed, 160 rpm. These conditions were validated experimentally with improved EPS yield of 1.33 g/L. The developed solid seed can be conveniently used for G. lucidum submerged culture with improved EPS productivity.

Increased production of ganoderic acids by overexpression of homologous farnesyl diphosphate synthase and kinetic modeling of ganoderic acid production in Ganoderma lucidum

Background

Ganoderic acids (GAs), derived from the medicinal mushroom Ganoderma lucidum, possess anticancer and other important pharmacological activities. To improve production of GAs, a homologous farnesyl diphosphate synthase (FPS) gene was overexpressed in G. lucidum. Moreover, the influence of FPS gene overexpression on GA production was investigated by developing the corresponding mathematical models.

Results

The maximum levels of total GAs and individual GAs (GA-T, GA-S, and GA-Me) in the transgenic strain were 2.76 mg/100 mg dry weight (DW), 41 ± 2, 21 ± 5, and 28 ± 1 μg/100 mg DW, respectively, which were increased by 2.28-, 2.27-, 2.62-, and 2.80-folds compared with those in the control. Transcription levels of squalene synthase (SQS) and lanosterol synthase (LS) genes during GA biosynthesis were upregulated by 2.28- and 1.73-folds, respectively, in the transgenic G. lucidum. In addition, the developed unstructured models had a satisfactory fit for the process of GA production in submerged cultures of G. lucidum. Analysis of the kinetic process showed that FPS gene overexpression had a stronger positive impact on GA production compared with its influence on cell growth. Also, FPS gene overexpression led to a higher non-growth-associated-constant β (1.151) over the growth-associated-constant α (0.026) in the developed models.

Conclusions

FPS gene overexpression is an effective strategy to improve the production of GAs in G. lucidum. The developed mathematical models are useful for developing a better GA production process in future large-scale bioreactors.

Electronic supplementary material

The online version of this article (10.1186/s12934-019-1164-3) contains supplementary material, which is available to authorized users.

Meroterpenoids from Ganoderma Species: A Review of Last Five Years

Meroterpenoids are hybrid natural products that partially originate from the terpenoid pathway. Ganoderma meroterpenoids (GMs) are a type of meroterpenoids containing a 1,2,4-trisubstituted phenyl and a polyunsaturated terpenoid part. Over last 5 years, great efforts have been made to conduct phytochemistry research on the genus Ganoderma, which have led to the isolation and identification of a number of GMs. These newly reported GMs showed diverse structures and a wide range of biological activities. This review gives an overview of new GMs from genus Ganoderma and their biological activities and biosynthetic pathway, focusing on the period from 2013 until 2018.

The effects of freeze-dried Ganoderma lucidum mycelia on a recurrent oral ulceration rat model

Background

Conventional scientific studies had supported the use of polysaccharides and β-glucans from a number of fungi, including Ganoderma lucidum for the treatment of recurrent oral ulceration (ROU). Our aim of the present study was to evaluate whether freeze-dried powder from G. lucidum mycelia (FDPGLM) prevents ROU in rats.

Methods

A Sprague-Dawley (SD) rat model with ROU was established by autoantigen injection. The ROU rats were treated with three different dosages of FDPGLM and prednisone acetate (PA), and their effects were evaluated according to the clinical therapeutic evaluation indices of ROU.

Results

High-dose FDPGLM induced significantly prolonged total intervals and a reduction in the number of ulcers and ulcer areas, thereby indicating that the treatment was effective in preventing ROU. Enzyme-linked immunosorbent assay (ELISA) showed that high-dose FDPGLM significantly enhanced the serum transforming growth factor-β1 (TGF-β1) levels, whereas reduced those of interleukin-6 (IL-6) and interleukin-17 (IL-17). Flow cytometry (FCM) showed that the proportion of CD4⁺ CD25⁺ Foxp3⁺ (forkhead box P3) regulatory T cells (Tregs) significantly increased by 1.5-fold in the high-dose FDPGLM group compared to that in the rat model group (P < 0.01). The application of middle- and high-dose FDPGLM also resulted in the upregulation of Foxp3 and downregulation of retinoid-related orphan receptor gamma t(RORγt) mRNA.

Conclusion

High-dose FDPGLM possibly plays a role in ROU by promoting CD4⁺ CD25⁺ Foxp3⁺ Treg and inhibiting T helper cell 17 differentiation. This study also shows that FDPGLM may be potentially used as a complementary and alternative medicine treatment scheme for ROU.

Electronic supplementary material

The online version of this article (10.1186/s12906-017-2021-8) contains supplementary material, which is available to authorized users.

Overexpression of the Squalene Epoxidase Gene Alone and in Combination with the 3-Hydroxy-3-methylglutaryl Coenzyme A Gene Increases Ganoderic Acid Production in Ganoderma lingzhi

The squalene epoxidase (SE) gene from the biosynthetic pathway of ganoderic acid (GA) was cloned and overexpressed in Ganoderma lingzhi. The strain that overexpressed the SE produced approximately 2 times more GA molecules than the wild-type (WT) strain. Moreover, SE overexpression upregulated lanosterol synthase gene expression in the biosynthetic pathway. These results indicated that SE stimulates GA accumulation. Then, the SE and 3-hydroxy-3-methylglutaryl coenzyme A (HMGR) genes were simultaneously overexpressed in G. lingzhi. Compared with the individual overexpression of SE or HMGR, the combined overexpression of the two genes further enhanced individual GA production. The overexpressing strain produced maximum GA-T, GA-S, GA-Mk, and GA-Me contents of 90.4 ± 7.5, 35.9 ± 5.4, 6.2 ± 0.5, and 61.8 ± 5.8 μg/100 mg dry weight, respectively. These values were 5.9, 4.5, 2.4, and 5.8 times higher than those produced by the WT strain. This is the first example of the successful manipulation of multiple biosynthetic genes to improve GA content in G. lingzhi.

Overexpression of the homologous lanosterol synthase gene in ganoderic acid biosynthesis in Ganoderma lingzhi

Ganoderic acids (GAs) in Ganoderma lingzhi exhibit anticancer and antimetastatic activities. GA yields can be potentially improved by manipulating G. lingzhi through genetic engineering. In this study, a putative lanosterol synthase (LS) gene was cloned and overexpressed in G. lingzhi. Results showed that its overexpression (OE) increased the ganoderic acid (GA) content and the accumulation of lanosterol and ergosterol in a submerged G. lingzhi culture. The maximum contents of GA-O, GA-Mk, GA-T, GA-S, GA-Mf, and GA-Me in transgenic strains were 46.6 ± 4.8, 24.3 ± 3.5, 69.8 ± 8.2, 28.9 ± 1.4, 15.4 ± 1.2, and 26.7 ± 3.1 μg/100 mg dry weight, respectively, these values being 6.1-, 2.2-, 3.2-, 4.8-, 2.0-, and 1.9-times higher than those in wild-type strains. In addition, accumulated amounts of lanosterol and ergosterol in transgenic strains were 2.3 and 1.4-fold higher than those in the control strains, respectively. The transcription level of LS was also increased by more than five times in the presence of the G. lingzhi glyceraldehyde-3-phosphate dehydrogenase gene promoter, whereas transcription levels of 3-hydroxy-3-methylglutaryl coenzyme A enzyme and squalene synthase did not change significantly in transgenic strains. This study demonstrated that OE of the homologous LS gene can enhance lanosterol accumulation. A large precursor supply promotes GA biosynthesis.