|gills on hymenium|
|cap is infundibuliform|
|hymenium is decurrent|
|stipe is bare|
|spore print is yellow|
|ecology is saprotrophic|
Omphalotus japonicus, commonly known as the tsukiyotake (月夜茸), is an orange to brown-colored gilled mushroom native to Japan and Eastern Asia. It is a member of the cosmopolitan genus Omphalotus, the members of which have bioluminescent fruit bodies which glow in darkness. A 2004 molecular study shows it to be most closely related to the jack'o'lantern fungus (Omphalotus olearius) of eastern North America.
Omphalotus japonicus is poisonous, its consumption resulting in acute nausea and vomiting for several hours. It is often confused with edible fungi and mistakenly consumed in Japan.
Inoko first described this fungus as Pleurotus noctilucens in 1889, however the name proved invalid as the binomial had already been used for another species. Given the name Pleurotus japonicus by Seiichi Kawamura in 1915, it was given the name Lampteromyces japonicus by Rolf Singer in 1947, until the genus Lampteromyces was sunk into Omphalotus in 2004. Hitoshi Neda has proposed this fungus is the same as one described by Miles Joseph Berkeley as Agaricus guepiniformis in 1878, as the type specimen fits the description of O. japonicus and hence, based on the principle of priority, the name should be Omphalotus guepiniformis (Berk.) Neda. A proposal was submitted in 2006 to conserve the epithet japonicus against guepiniformis and another synonym, Pleurotus harmandii. The proposal was accepted by the Nomenclature Committee for Fungi in 2008.
The fleshy fruit bodies have an eccentric stem rendering the cap kidney- or half-moon-shaped and only round when young. The cap is light brown when young and darkens with age, with yellow or pinkish tinges. The flesh is white and up to 2 cm (0.8 in) thick in the cap. The thick white gills are decurrent and can yellow with age. The stem is thick and fleshy and can be up to 2 cm (0.8 in) thick and 5 cm (2 in) long. The gills glow with a whitish light. Kawamura reported that the fungi can be seen from 30 m (100 ft) away at night, and that 100 square centimetres of glowing mushrooms allowed him to read Roman characters of 8 mm size by their light.
This fungus is mistaken for the commonly eaten oyster mushroom (Pleurotus ostreatus), but is poisonous. O. japonicus was responsible for 31.6% of poisoning cases in Japan between 1996 and 2005—more than any other mushroom. Symptoms of O. japonicus poisoning are nausea, vomiting and diarrhea. The most common treatment is fluid therapy.
Habitat and distribution
The fungus grows on dead beech trees, and is found in mountainous regions of Japan, the fruit bodies appearing in September and October. One of the most common mushrooms growing on decaying beech wood in that country, it is classified as "Vulnerable" because beech forests are being depleted. It is also found in Korea, China, and far eastern Russia.
- "Omphalotus japonicus (Kawam.) Kirchm. & O.K. Mill.". MycoBank. International Mycological Association. http://www.mycobank.org/BioloMICS.aspx?Table=Mycobank&Rec=411196&Fields=All. Retrieved 2012-11-21.
- Neda, Hitoshi (2004). "Type studies of Pleurotus reported from Japan". Mycoscience 45: 181–87. doi:10.1007/s10267-003-0172-6.
- Redhead, Scott A.; Neda, Hitoshi (2006). "(1741) Proposal to Conserve the Name Pleurotus japonicus against Agaricus guepiniformis and Pleurotus harmandii (Basidiomycota)". Taxon 55 (4): 1032–33. JSTOR 25065705.
- Kirchmair M, Morandell S, Stolz D, Pöder R, Sturmbauer C. (2004). "Phylogeny of the genus Omphalotus based on nuclear ribosomal DNA-sequences". Mycologia 96 (6): 1253–60. JSTOR 3762142. PMID 21148949. http://www.cybertruffle.org.uk/cyberliber/59350/0096/006/1253.htm.
- Norvell, Lorelei L. (2008). "Report of the Nomenclature Committee for Fungi: 14". Taxon 57 (2): 637–39. JSTOR 25066033.
- Kawamura, Seiichi (1915). "Studies on the luminous fungus, Pleurotus japonicus, sp. nov.". Journal of the College of Science, Imperial University of Tokyo 35: 1–29. http://repository.dl.itc.u-tokyo.ac.jp/dspace/bitstream/2261/32970/1/jcs035003.pdf.
- Tsurida, Sayuri; Akai, Kouichi; Hiwaki, Hiroshi; Suzuki, Akira; Akiyama, Hiroshi (2012). "Multiplex real-time PCR assay for simultaneous detection of Omphalotus guepiniformis and Lentinula edodes" (PDF). Bioscience, Biotechnology, and Biochemistry 76 (7): 1343–49. doi:10.1271/bbb.120090. https://www.jstage.jst.go.jp/article/bbb/76/7/76_120090/_pdf.
- Hayashida, Akiko; Seino, Keiko; Iseki, Ken (2011). "Treatment of mushroom poisoning by Lampteromyces japonicus; four case reports and review of the literature" (in Japanese). Yamagata Medical Journal 29 (2): 57–62. ISSN 0288-030X.
- Fukasawa, Yu; Osono, Takashi; Takeda, Hiroshi (2010). "Beech log decomposition by wood-inhabiting fungi in a cool temperate forest floor: a quantitative analysis focused on the decay activity of a dominant basidiomycete Omphalotus guepiniformis". Ecological Research 25: 959–66. doi:10.1007/s11284-010-0720-4.
- Ka, K.H.; Park, H.; Hur, T.C.; BAc, W.C. (2010). "Formation of fruiting body of Omphalotus japonicus by sawdust cultivation". The Korean Journal of Mycology 38 (1): 80–82. ISSN 0253-651X.
- Tanaka, K.; Inoue, T.; Kadota, S.; Kikuchi, T. Metabolism of illudin S, a toxic principle of Lampteromyces japonicus, by rat liver. I. Isolation and identification of cyclopropane ring-cleavage metabolites (1990). Xenobiotica 20: 671–81.
- Tanaka, K.; Inoue, T.; Kadota, S.; Kikuchi, T. Metabolism by rat liver cytosol of illudin S, a toxic substance of Lampteromyces japonicus. II. Characterization of illudin S-metabolizing enzyme (1992). Xenobiotica 22: 33–39.
- Tanaka, K.; Inoue, T.; Tezuka, Y.; Kikuchi, T. (1996). "Metabolism of illudin S, a toxic substance of Lampteromyces japonicus: urinary excretion of mercapturic acids in rat". Xenobiotica 26: 347–54.
- Tanaka, K.; Inoue, T.; Tezuka, Y.; Kikuchi, T. (1996). "Michael-type addition of illudin S, a toxic substance from Lampteromyces japonicus, with cysteine and cysteine-containing peptides in vitro". Chemical and Pharmacological Bulletin 44: 273–79.
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