Calvatia gigantea
1. Classification
Higher order taxa
Domain: Eukarya Phylum: Basidiomycota Class: Agaricomycetes Order: Agaricales Family: Lycoperdaceae Genus: Calvatia [5] Species Group: Calvatia gigantea [5]
2. Description and significance
Calvatia gigantea, also known as the Giant Puffball Mushroom, is a fungus found in various parts of the world. It is mainly widespread in temperate zones during late summer and autumn [1], [2]. C. gigantea has historically been used as an edible and medicinal fungus in Chinese, North American, Mongolian, and Russian cultures [2], [3], [4]. As the species name suggests, C. gigantea is noted for the size of its fruiting bodies, which can range from 20 cm to 150 cm in diameter [1]. While the genome structure, molecular composition, and potential applications of C. gigantea in both dietary and pharmacological contexts have been thoroughly investigated through past and current research, an ongoing debate concerning C. gigantea revolves around its capability for mycorrhizal associations, which are its mutualistic relationship with plant roots. Some studies support potential mutualistic relationships, while others refute it, contributing to the ongoing discourse in the scientific community [5].
3. Genome structure
Calvatia gigantea possesses a genome size of 46,042,072 base pairs, 47% of which are guanine-cytosine pairings [6]. With respect to the Basidiomycota phylum, it contains an estimated 15,431 genes and 5.28 exons per gene [7]. Phylogenetically, it is most closely related to Calvatia bicolor, Calvatia pachyderma, and Calvatia candida via the internal transcribed spacer, all of whose sequence similarity identifies C. gigantea, morphologically, as belonging to the Calvatia species rather than the Lycoperdon species [8]. The chromosome number, determined as n=4, manifests in metaphase and anaphase I as three bivalents [9]. Additionally, its basidiospores, which are found inside the fruiting body of C. gigantea, contain sister nuclei [9].
4. Cell structure
Calvatia gigantea displays a complex cell structure. Stained squash preparations of young puffballs revealed that the subterminal cells are binucleate, indicating the presence of two nuclei in these cells [9]. In larger C. gigantea, the tissue is composed of larger hyphae with clamp connections, each housing a pair of fairly large nuclei arranged in pairs. However, smaller C. gigantea are characterized by smooth hyphae with absent clamp connections [9]. The spore diameter measures between 8-10 µm, and the hyphae are approximately 10 µm in diameter. The fungus displays a dikaryotic state, with haploid fruiting bodies growing from a haploid mycelium [9]. Basidiospores receive one nucleus from the basidium and divide once, resulting in each spore containing two sister nuclei [9]. Through using smear techniques to isolate cells, it was discovered that the fungus contains a variety of amino acids; the concentrations of total free, essential, and non-essential amino acids were 199.65 mg/100g, 113.69 mg/100g, and 85.96 mg/100g, respectively [8].
5. Metabolic processes
Calvatia gigantea is classified as heterotrophic, saprotrophic, and mycorrhizal, deriving energy from organic nitrogen sources and associating with the Pinus and Picea tree and shrub species [2], [3], [11]. C. gigantea also sources carbon from plant phenolic components to drive its metabolism, most notably from the polyphenolic tannins [12]. In terms of the nutritional composition of C. gigantea, it is composed of 67.93% polyunsaturated fatty acid, 51.97% carbohydrates, 34.37% protein, and 4.11% fat [14]. Its most abundant compounds include gentisic acid, at a concentration of 23.26 µg/g, trehalose, at a concentration of 9.78g/100g, and hexanal, comprising 34.71% of all aromatic compounds identified [14]. Individually, these function as phenolic, sugar, and aromatic compounds, respectively [14].
6. Ecology
Calvatia gigantea is found in forests, wooded gardens, fields and meadows, and prefers cultivated lands over natural habitats [1], [5]. C. gigantea grows during the summer and autumn seasons, requiring complete shade during its early developmental stages, and remaining shade-loving as well as intense-light-tolerant in its mature stage [1], [5]. C. gigantea is usually found in Central Europe, common in countries like Scotland and the Netherlands and rare in countries like the United Kingdom and Poland. There are some speculations of C. gigantea having facultative mycorrhizal relationships with the roots of plants, such as those from the Pinus and Picea tree and shrub species, as it is also known to form fairy rings [5], [11].
C. gigantea grows at an optimal pH of 6, and inorganic nitrogen sources like ammonium sulfate also enhance its mycelial growth [2]. The optimal temperature for fermentation is 26°C, suggesting that this particular fungus thrives and grows most efficiently in hot, grassland environments [2]. However, C. gigantea may be adaptable to other environments as well. Research revealed that C. gigantea populations were found in certain regions in Mongolia and Russia. C. gigantea exhibited great variability in how its populations would thrive in specific climates, having a climate score, an index measuring its suitable environment conditions, ranging from 3.2 to 7.3 points [4]. This range indicates significant disparities in how the mushroom may adapt to mountainous habitats with extreme and fluctuating low-oxygen and cold-temperature conditions [4].
7. Pathology
Although C. gigantea is a non-poisonous, non-pathogenic fungus, a mature specimen produces basidiospores that are capable of causing disease if inhaled in large quantities. C. gigantea basidiospores have been proposed to act on the respiratory system by means of depositing in the alveoli via hyphal embedment, thereby triggering a hypersensitive immune response [15]. Lycoperdonosis is one such disease caused by C. gigantea and other puffball mushrooms, whose symptoms include pneumonitis, labored and rapid breathing, fever, cyanosis, and vomiting. These symptoms are typically treated with antifungals and corticosteroids to suppress inflammatory response [15].
8. Impact on Health
Supplemental value
C. gigantea, like all Calvatia species, is edible, but only before spore maturation. C. gigantea is regarded as being gastronomically favorable amongst puffball species for its diverse nutritional profile [5]. The low fat and high protein content of C. gigantea makes this mushroom a rich source of nutrients [14]. Amino acid profiling results also suggest it as being rich in essential and non-essential, readily usable, free amino acids, making it a good source for free amino acid supplement intake [10].
Pharmacological value
Historically, Calvatia gigantea has been used as a haemostatic and for wound dressings, treating a variety of ailments such as leucorrhoea, pneumaturia, inflammation, and diarrhea, in Chinese, North American, Mongolian, and Russian cultures [2], [3], [4], [5]. Chemical composition studies show that such versatility exhibited by C. gigantea is due to it being rich in polyunsaturated fatty acids, proteins, and carbohydrates [14]. These particular chemical composition studies pointed out some important compounds it produces, one of which is the mucoprotein, calvacin. Calvacin is known to inhibit the proliferation of human lung cancer cells, demonstrating that its anticancer properties may have potential to be utilized in the pharmaceutical market, and may be a less adverse alternative to standard anticancer drugs [13], [16]. Calvacin not only serves in lung cancer treatment, but may also serve as an antidiabetic agent by lowering blood sugar levels [8]. Furthermore, C. gigantea is rich in compounds responsible for antioxidant activities, and is thus considered a suitable candidate for antioxidant-rich foods [14]. Interestingly, additional research shows that C. gigantea is effective against several viruses, particularly the influenza virus [17], [18].
9. Current Research
Biochemical and ecological properties
There have been recent studies investigating the biochemical properties of Calvatia gigantea responsible for its medicinal and nutritional properties. C. gigantea displays antidiabetic effects; C. gigantea can inhibit amylase production, and blood-glucose spiking in response to postprandial hyperglycemia [8]. Another development in understanding C. gigantea’s ecology was identifying it as an ectomycorrhizal fungi of Pinus and Picea trees and other plant species, characterized by its symbiotic association with their plant roots to encourage water and mineral intake [1], [11].
Extract of Calvatia gigantea and apoptosis of cancer cells
Recent research has found that C. gigantea is able to induce cell cycle arrest and apoptosis in A549 lung carcinoma cells, inhibiting their growth [13]. It achieves this by downregulating the expression of key genes involved in cell cycle arrest, including CCND1, CCND2, CDK4, and Akt; and apoptosis, including Bax, p53, caspase-3, and caspase-9 [13]. The most effective dose needed to harm A549 cells was 500 µg/mL of mushroom extract for 72 hours. However, further research is needed to determine the mushroom’s safest dose for maximizing its anticancer effects on the human body [13].
10. References
[1] Dago Dueñas, Y., Calzadilla Reyes, K., Redonet Miranda, M. D. L. Á., & Suarez Mesa, A. G. (2023). Species of ectomycorrhizal fungi in two ecosystems of the Plan Café locality. Revista Cubana de Ciencias Forestales, 11(1).
[2] Zhu, W., Guo, C., Luo, F., Zhang, C., Wang, T., & Wei, Q. (2015). Optimization of Calvatia gigantea Mycelia Production from Distillery Wastewater. Wiley Online Library, 121(1), 78-86.
[3] Burk, W. R. (1983). Puffball usages among North American Indians. Journal of Ethnobiology, 3(1), 55-62.
[4] Kherlenchimeg, N., Baikov, K., & Burenbaatar, G. (2020). Ecotypification of local populations of rare species Calvatia gigantea (Basidiomycota: Agaricales) in ultracontinental zones of Mongolia and Russia. BIO Web of Conferences, 24, 00034.
[5] Coetze, J. C., & Van Wyk, A. E. (2009). The genus Calvatia (‘Gasteromycetes’, Lycoperdaceae): A review of its ethnomycology and biotechnological potential. African Journal of Biotechnology, 8(22).
[6] ASM2509398v1. Bethesda (MD): National Library of Medicine (US), National Center for Biotechnology Information; 2004 -
[7] Mohanta, T.K., & Bae, H. (2015). The diversity of the fungal genome. Biological Procedures Online, 17(8), 8
[8] Ogbole, O. O., Nkumah, A. O., Linus, A. U., & Falade, M. O. (2019). Molecular identification, in vivo and in vitro activities of Calvatia gigantea (macro-fungus) as an antidiabetic agent. Mycology, 10(3), 166-173.
[9] Dowding, E. S., & Bulmer, G. S. (1964). Notes on the cytology and sexuality of puffballs. Canadian Journal of Microbiology, 10(5), 783–789.
[10] Kıvrak, İ., Kıvrak, Ş., & Harmandar, M. (2014). Free amino acid profiling in the giant puffball mushroom (Calvatia gigantea) using UPLC–ms/MS. Food Chemistry, 158, 88-92. 11. Trappe, J. M. (1962). Fungus associated of Ectotrophic mycorrhizae. The Botanical Review, 28(4), 538-606.
[12] Galiotou-Panayotou, M., & Macris, B. J. (1986). Degradation of condensed tannins by Calvatia gigantea. Applied Microbiology and Biotechnology, 23(6), 502-506.
[13] Eroğlu, C., Seçme, M., Atmaca, P., Kaygusuz, O., Gezer, K., Bağcı, G., & Dodurga, Y. (2016). Extract of Calvatia gigantea inhibits proliferation of A549 human lung cancer cells. Cytotechnology, 68(5), 2075-2081.
[14] Kıvrak, İ., Kıvrak, Ş., & Harmandar, M. (2016). Bioactive compounds, chemical composition, and medicinal value of the giant puffball, Calvatia gigantea (higher basidiomycetes), from Turkey. International Journal of Medicinal Mushrooms, 18(2), 97–107.
[15] Munson, E. L., Panko, D. M., & Fink, J. G. (1997). Lycoperdonosis: Report of Two Cases and Discussion of the Disease. Clinical Microbiology Newsletter, 19(3), 17-21.
[16] Ren, L., Hemar, Y., Perera, C.O., Lewis, G., Krissansen, G.W. and Buchanan, P.K. (2014). Antibacterial and antioxidant activities of aqueous extracts of eight edible mushrooms. Bioactive Carbohydrates and Dietary Fibre, 3(2): 41–51.
[17] Kekos, D. and Macris, B.J. (1987). Effect of tannins on growth and amylase production by Calvatia gigantea. Enzyme and Microbial Technology, 9(2): 94–96.
[18] Piearce, G.D. (1981). Zambian mushrooms—Customs and folklore. Bulletin of the British Mycological Society, 15(2): 139–142.
Edited by students of Jennifer Bhatnagar for BI311: General Microbiology, 2023, Boston University.
