Tremella mesenterica (common names include yellow brain, golden jelly fungus, yellow trembler, and witches' butter) is a common jelly fungus in the Tremellaceae family of the Agaricomycotina. It is most frequently found on dead but attached and on recently fallen branches, especially of angiosperms, as a parasite of wood decay fungi in the genus Peniophora. The gelatinous, orange-yellow fruit body of the fungus, which can grow up to 7.5 cm (3.0 in) diameter, has a convoluted or lobed surface that is greasy or slimy when damp. It grows in crevices in bark, appearing during rainy weather. Within a few days after rain it dries into a thin film or shriveled mass capable of reviving after subsequent rain. This fungus occurs widely in deciduous and mixed forests and is widely distributed in temperate and tropical regions that include Africa, Asia, Australia, Europe, North and South America. Although considered bland and flavorless, the fungus is edible. Tremella mesenterica produces carbohydrates that are attracting research interest because of their various biological activities.
Taxonomy and phylogeny
|Phylogeny and relationships of T. mesenterica and related species based on rDNA sequences.|
The species was originally described from Sweden as Helvella mesenterica by the naturalist Anders Jahan Retzius in 1769. It was later (1822) sanctioned by Elias Magnus Fries in the second volume of his Systema Mycologicum. It is the type species of the genus Tremella. Its distinctive appearance has led the species to accumulate a variety of common names, including "yellow trembler", "yellow brain", "golden jelly fungus", and "witches' butter", although this latter name is also applied to Exidia glandulosa. The specific epithet is a Latin adjective formed from the Ancient Greek word μεσεντεριον (mesenterion), "middle intestine", from μεσο- (meso-, "middle, center") and εντερον (enteron, "intestine"), referring to its shape.
Based on molecular analysis of the sequences of the D1/D2 regions of the large subunit ribosomal RNA gene and the internal transcribed spacer regions of rRNA, T. mesenterica is most closely related to T. coalescens, T. tropica, and T. brasiliensis. This analysis included 20 of the estimated 120 Tremella species.
The fruit body has an irregular shape, and usually breaks through the bark of dead branches. It is up to 7.5 cm (3.0 in) broad and 2.5 to 5.0 cm (1.0 to 2.0 in) high, rounded to variously lobed or brain-like in appearance. The fruit body is gelatin-like but tough when wet, and hard when dry. The surface is usually smooth, the lobes translucent, deep yellow or bright yellow-orange, fading to pale yellow, rarely unpigmented and white or colorless. The fruit bodies dry to a dark reddish or orange. The spores, viewed in mass, are whitish or pale yellow.
The basidia (spore-bearing cells) are ellipsoid to roughly spherical in shape, not or rarely stalked, and typically 15–21 µm wide. They contain two to four septa that divide it into compartments; the septa are most frequently diagonal or vertical. Asexual reproduction in T. mesenterica is carried out through the formation of spores called conidia, which arise from conidiophores—specialized hyphal cells that are morphologically distinct from the somatic hyphae. The conidiophores are densely branched and normally abundant in the hymenium; young specimens may be entirely conidial. The conidia are roughly spherical, ovoid, or ellipsoid, and about 2.0–3.0 by 2.0–2.5 µm. They may be so numerous that young fruit bodies may be covered in a bright yellow, conidial slime. The spores are broadly ellipsoid to oblong, on average 10.0–16.0 by 6.0–9.5 µm; they germinate by germ tube or by yeast-like conidia of identical form to the conidia produced on the conidiophores.
Although some have claimed the fungus to be inedible or merely "non-poisonous", most other sources agree that it is edible but flavorless. The gelatinous to rubbery consistency lends texture to soups. In China, the fungus is used by vegetarians to prepare "an immunomodulating cooling soup with lotus seed, lily bulbs, jujube, etc."
Tremella mesenterica is frequently confused with Tremella aurantia, a widespread species parasitic on the plant pathogenic fungus Stereum hirsutum. Tremella aurantia can often be recognized by the presence of its host, which typically grows on logs, stumps, and trunks. Though the two species are similarly colored, the surface of T. aurantia is usually matte, not greasy or shiny, and its lobes or folds are thicker than those of T. mesenterica. Fruit bodies of T. aurantia contain unclamped, thick-walled host hyphae and consequently retain their shape when dried, rather than shriveling or collapsing to a film (as in T. mesenterica). Microscopically, T. aurantia has smaller basidia and smaller, differently shaped spores measuring 8.5–10 by 7–8.5 µm. T. brasiliensis, known from neotropical areas and Japan, and the North American species T. mesenterella are also similar.
Tremella mesenterica may also be confused with members of the Dacrymycetaceae family, like Dacrymyces chrysospermus (formerly D. palmatus), due to their superficial resemblance. Microscopic examination shows that the Dacrymycetaceae have Y-shaped basidia with two spores, unlike the longitudinally split basidia characteristic of Tremella; additionally, D. chrysospermus is smaller, has a whitish attachment point to its substrate, and grows on conifer wood.
Tremella mesenterica has a yeastlike phase in its life cycle that arises as a result of budding of basidiospores. The alternation between asexual and sexual propagation is achieved by mating of yeast-form haploid cells of two compatible mating types. Each mating type secretes a mating pheromone that elicits sexual differentiation of the target cell having the opposite mating type to the pheromone-producing cell. The sexual differentiation is characterized by the arrest of the growth in the G1 phase of the cell division cycle and subsequent formation of an elongated mating tube. Formation of the mating tube, initiated by the pheromones A-10 and a-13, is similar to the process of bud emergence during bipolar budding in yeasts. Tremerogen A-10 has been purified and its chemical structure found to be S-polyisoprenyl peptide. Fruit bodies arise from a primordium located beneath the wood bark, and sometimes more than one fruit body can originate separately from the same primordia.
Habitat and distribution
Tremella mesenterica has a cosmopolitan distribution, having been recorded from Europe, North, Central, and South America, Africa, Asia, and Australia. Fruit bodies are formed during wet periods throughout the year. In British Columbia, Canada, it is sometimes found on maple, poplar, or pine, but is most abundant on red alder. It prefers to grow in habitats ranging from mesic to wet. The fungus grows parasitically on the mycelium of wood-rotting corticioid fungi in the genus Peniophora. Occasionally, T. mesenterica and its host fungus can be found fruiting together.
Some Tremella species produce polysaccharides that are of interest to the medical field, because of their biological activity; several patents have been filed in China pertaining to the use of these compounds for cancer prevention or immune system enhancement. In 1966, Slodki reported discovering an acidic polysaccharide from haploid cells of T. mesenterica that closely resembled those produced by the species Cryptococcus laurentii. The structural similarity of the polysaccharides from the two species suggested a phylogenetic relationship between them. Subsequently, researchers chemically synthesized the polysaccharide, and determined the chemical identities of the component sugar units. The polysaccharide, known as glucuronoxylomannan—produced by fruit bodies and in pure culture conditions—has been shown to consist of a mannan backbone that is acetylated with xylan chains in a regular repeating structure. Laboratory tests have associated a number of biological activities with T. mesenterica glucuronoxylomannan, including immunostimulatory, protecting against radiation, antidiabetic, anti-inflammatory, hypocholesterolemic, hepatoprotective, and antiallergic effects.
- "Tremella mesenterica (Schaeff.) Retz. 1769". MycoBank. International Mycological Association. Retrieved 2010-07-01.
- Alternatively spelled witch's or witches
- Zugmaier W, Bauer R, Oberwinkler F. (1994). "Mycoparasitism of some Tremella species". Mycologia 86 (1): 49–56. doi:10.2307/3760718. JSTOR 3760718.
- Fell JW, Boekhout T, Fonseca A, Scorzetti G, Statzell-Tallman A. (2000). "Biodiversity and systematics of basidiomycetous yeasts as determined by large-subunit rDNA D1/D2 domain sequence analysis" (PDF). International Journal of Systematic and Evolutionary Microbiology 50 (3): 1351–71. doi:10.1099/00207713-50-3-1351. PMID 10843082.
- Fries EM. (1822). Systema Mycologicum (in Latin) 2. Lundae: Ex Officina Berlingiana. p. 214. Retrieved 2010-03-08.
- Bandoni R, Ginns J. (1998). "Notes on Tremella mesenterica and allied species". Canadian Journal of Botany 76 (9): 1544–57. doi:10.1139/cjb-76-9-1544.
- Bandoni RJ, Szczawinski AF. (1976). Guide to Common Mushrooms of British Columbia. Vancouver, Canada: British Columbia Provincial Museum. p. 202.
- Kirk PM, Cannon PF, Minter DW, Stalpers JA. (2008). Dictionary of the Fungi (10th ed.). Wallingford, UK: CABI. p. 733. ISBN 978-0-85199-826-8.
- Oxford English Dictionary Online. Oxford: Oxford University Press. 2010. ss. vv. "mesenterium".
- Roody WC. (2003). Mushrooms of West Virginia and the Central Appalachians. Lexington, Kentucky: University Press of Kentucky. p. 454. ISBN 0-8131-9039-8. Retrieved 2010-03-08.
- Jordan M. (2004). The Encyclopedia of Fungi of Britain and Europe. London: Frances Lincoln. p. 372. ISBN 0-7112-2378-5.
- Kuo M. (2008). "Tremella mesenterica: Witch's Butter". MushroomExpert.Com. Retrieved 2010-03-07.
- Roberts P. (1995). "British Tremella species I: Tremella aurantia and T. mesenterica". Mycologist 9 (3): 110–114. doi:10.1016/S0269-915X(09)80270-X.
- Boa E. (2004). Wild Edible Fungi: A Global Overview Of Their Use And Importance To People (Non-Wood Forest Products). Food & Agriculture Organization of the UN. p. 140. ISBN 92-5-105157-7.
- Metzler V, Metzler S. (1992). Texas Mushrooms: a Field Guide. Austin, Texas: University of Texas Press. p. 330. ISBN 0-292-75125-7. Retrieved 2010-03-08.
- Volk T. (2000). "Tremella mesenterica, witch's butter, Tom Volk's Fungus of the Month for October 2000". University of Wisconsin-La Crosse. Retrieved 2010-03-07.
- Arora D. (1991). All that the Rain Promises and More: a Hip Pocket Guide to Western Mushrooms. Berkeley, California: Ten Speed Press. p. 242. ISBN 0-89815-388-3.
- Davidson JL, Davidson A, Saberi H, Jaine T. (2006). The Oxford Companion to Food. Oxford [Oxfordshire]: Oxford University Press. p. 420. ISBN 0-19-280681-5.
- Hu, Shiu-ying (2005). Food Plants of China. Hong Kong: Chinese University Press. p. 269. ISBN 962-996-229-2.
- Smith KN. (2005). A Field Guide to the Fungi of Australia. Sydney, Australia: UNSW Press. p. 68. ISBN 0-86840-742-9. Retrieved 2010-03-07.
- Orr DB, Orr RT. (1979). Mushrooms of Western North America. Berkeley: University of California Press. pp. 48–49. ISBN 0-520-03656-5.
- Bandoni RJ. (1965). "Secondary control of conjugation in Tremella mesenterica". Canadian Journal of Botany 43 (6): 627–30. doi:10.1139/b65-069.
- Hirata A, Tsuchiya E, Fukui S, Tanaka K. (1980). "An electron microscopic study on the mating tube formation in the heterobasidiomycete Tremella mesenterica". Archives of Microbiology 128 (2): 215–21. doi:10.1007/BF00406161.
- Sakagami Y, Isogai A, Suzuki A, Kitada C, Fujino M. (1979). "Structure of tremerogen-a-10, a peptidal hormone inducing conjugation tube formation in Tremella mesenterica". Agricultural and Biological Chemistry 43 (12): 2643–45. doi:10.1271/bbb1961.43.2643.
- Lowy B. (1971). Flora neotropica. Monograph no. 6. Tremelalles. Hafner Publishing Company Inc.
- De Baets Sm Vandamme EJ. (2001). "Extracellular Tremella polysaccharides: structure, properties and applications". Biotechnology Letters 23 (17): 1361–66. doi:10.1023/A:1011645724220.
- Slodki ME, Wickerham LJ, Bandoni RJ. (1966). "Extracellular heteropolysaccharides from Cryptococcus and Tremella: a possible taxonomic relationship". Canadian Journal of Microbiology 12 (3): 489–94. doi:10.1139/m66-071. PMID 5962584.
- Fraser CG, Jennings HJ, Moyna P. (1973). "Structural analysis of an acidic polysaccharide from Tremella mesenterica NRRL Y-6158". Canadian Journal of Biochemistry 51 (3): 219–24. doi:10.1139/o73-027. PMID 4700340.
- Cherniak R, Jones RG, Slodki ME. (1988). "Type-specific polysaccharides of Cryptococcus neoformans. N.M.R.-spectral study of a glucuronomannan chemically derived from a Tremella mesenterica exopolysaccharide". Carbohydrate Research 182 (2): 227–39. doi:10.1016/0008-6215(88)84005-9. PMID 3072079.
- Vinogradov E, Petersen BO, Duus JØ. (2004). "The structure of the glucuronoxylomannan produced by culinary-medicinal yellow brain mushroom (Tremella mesenterica Ritz.:Fr., Heterobasidiomycetes) grown as one cell biomass in submerged culture". Carbohydrate Research 339 (8): 1483–89. doi:10.1016/j.carres.2004.04.001. PMID 15178391.
- Wasser SP, Tan K-K, Elisashvili VI. (2002). "Hypoglycemic, interferonogenous, and immunomodulatory activity of Tremellastin from the submerged culture of Tremella mesenterica Retz.: Fr. (Heterobasidiomycetes)". International Journal of Medicinal Mushrooms 4 (3): 215–27. doi:10.1615/intjmedmushr.v4.i3.40.
- Vinogradov E, Petersen BO, Duus JØ, Wasser SP. (2004). "The isolation, structure, and applications of the exocellular heteropolysaccharide glucuronoxylomannan produced by yellow brain mushroom Tremella mesenterica Ritz.:Fr. (Heterobasidiomycetes)". International Journal of Medicinal Mushrooms 6 (4): 335–45. doi:10.1615/IntJMedMushr.v6.i4.40.
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