Ganoderma lucidum

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A Microbial Biorealm page on the genus Ganoderma lucidum

Classification

Eukaryota; Opisthokonta; Fungi; Dikarya; Basidiomycota; Agaricomycotina; Agaricomycetes; Agaricomycetes incertae sedis; Polyporales; Ganodermataceae; Ganoderma; Ganoderma lucidum NCBI: Taxonomy Genome

Description and significance

The fruiting body of Ganoderma lucidum is commonly known as the medicinal reishi mushroom. Reishi has long been used in alternative medicine for its anti-microbial, anti-cancer, and antibiotic properties. Extracts from G. lucidum have been found to be selective against Bacillus subtilis. G. lucidum also produces anti-viral triterpenoids in the fruiting body, found to have significant anti-HIV-1 protease activity (1, 4, 7).

Genome structure

The genome of Ganoderma lucidum has not yet been completely mapped, although small sub-unit ribosomal DNA was used in phylogenetic resolution amongst the Ganodermas (3).

Cell structure, metabolism & life cycle

G. lucidum is an annual polyporous, shelf fungus which is found east of the Rocky Mountains in the northern United States (4). Polypores are fungi that have pores on the underside of their fruiting body rather than gills (1). The spore print of G. lucidum is brown (1). Cells are non-motile, with rigid cell walls containing chitin. The basal unit of G. lucidum is the hyphae which embed in live or dead wood substrate, and allow for heterotrophic nutrient absorption through enzyme secretion and breakdown of organic wood material (5). The fruiting body of G. lucidum is varnished reddish brown, with soft brown flesh that hardens quickly with age. Young tissue may also include yellows and lighter browns, or whites (1,4). A cap of 2-30 cm; at first knobby, but by maturity more or less fan-shaped can grow on a stem, causing white rot at the base, either alone or in clusters (1,4).

Ecology (including pathogenesis)

Ganoderma lucidum is parasitic on live hardwood (particularly oak) and saprophytic on deadwood of hardwood (4). Most often found growing on fallen hardwoods, or at the base of live trees.

Interesting feature

26-Oxygenosterols were analyzed in-vitro to measure their effects on cholesterol synthesis and the potential applications for lowering cholesterol in humans. The G. lucidum extract inhibited the conversion of lanosterol to lathosterol in human hepatic cell cultures. This has potential applications for patients suffering from high blood cholesterol levels, and also demonstrates the applicability of fungus extracts in medical testing (2) Extracted ganodermic acid from the fruiting body of G. lucidum was tested in vitro against malignant human breast carcinoma cells. Treatment by the extract resulted in tumor cell detachment, tumor cell death, and an inhibition of regrowth (6). Although the secondary metabolites of this fungus have long been utilized as agents of medicine, and the antiviral, antibiotic, anti-cancer and cholesterol lowering abilities have been demonstrated in laboratory settings, the FDA has yet to approve the clinical use of G. lucidum.

References

1. Engelbrecht, K., and Volk, T. 2005. Tom Volk’s Fungus of the Month March 2005. <http://botit.botany.wisc.edu/toms_fungi/mar2005.html> Accessed 10/26/2011.

2. Hajjaj, H., Mace, C., Roberts, M., Niederberger, P., and Fay, L.B. 2005. Effect of 26-Oxygenosterols from Ganoderma lucidum and Activity as Cholesterol Synthesis inhibitors. Applied and Environmental Microbiology. July: 3653-3658.

3. Hong, S.G., Jung, H. S. 2004. Phylogenetic analysis of Ganoderma based on nearly complete mitochondrial small-subunit ribosomal DNA sequences. Mycologia 96: 742-755.

4. Kuo, M. 2004. Ganoderma lucidum. Mushroom Expert Website. <http://www.mushroomexpert.com/ganoderma_lucidum.html> Accessed 10/27/2011.

5. Worrall, J. 2011. Fungi. Forest Pathology Website. <http://www.forestpathology.org/fungi.html> Accessed 10/31/2011.

6. Xie, Yi-Zhen, Li, Sen-Zhu, Yee, A., La Pierre, D.P., Deng, Z., Lee, D.Y., Wu, Qing-Ping, Li, C., Zhang, Z., Guo, J., Jiang, Z., and Yang, B.B. 2006. Ganoderma lucidum inhibits tumour cell proliferation and induces tumour cell death. Enzyme and Microbial Technology. 40(1): 177-185.

7. Zjawlony, J.K. 2004. Biologically Active Compounds from Aphyllophorales (polypore) Fungi. Journal of Natural Products. 67: 300-310.