Gyromitra esculenta

Taxobox
name = False Morel

regnum = Fungi
phylum = Ascomycota
classis = Ascomycetes
ordo = Pezizales
familia = Discinaceae
genus = "Gyromitra"
species = "G. esculenta"
binomial = "Gyromitra esculenta"
binomial_authority = (Pers. ex Pers.) Fr.mycomorphbox
name = Gyromitra esculenta
hymeniumType=smooth
capShape = convex
whichGills = NA
stipeCharacter=bare
sporePrintColor=yellow
sporePrintColor2=buff
ecologicalType=saprotrophic
ecologicalType2=mycorrhizal
howEdible2=deadly
howEdible=choice

"Gyromitra esculenta" is an ascomycete fungus from the genus "Gyromitra", widely distributed across Europe and North America and one of several species of fungi known as false morels. It normally sprouts in sandy soils under coniferous trees, in spring and early summer. The fruiting body, or mushroom, is an irregular brain-shaped cap dark brown in colour which can reach 10 cm (4 in) high and 15 cm (6 in) wide, perched on a stout white stipe up to 6 cm (2.4 in) high.

Although potentially fatal if eaten raw, "Gyromitra esculenta" is a popular delicacy in Scandinavia, Eastern Europe, and the upper Great Lakes region of North America. It may be sold fresh in Finland, but it must be accompanied by warnings and instructions on correct preparation. It is eaten in omelettes, soups, or sautéed in Finnish cuisine. Once popular in the Pyrenees, it is now prohibited from sale for consumption in Spain.

Although it is still commonly consumed after parboiling, recent evidence suggests that even this procedure may not make the fungus entirely safe;cite book |last=Dart| first= Richard C. |chapter=Mushrooms |title=Medical toxicology |publisher=Williams & Wilkins| location=Philadelphia |year=2004|pages=1719–35| isbn=0-7817-2845-2] thus raising concerns of risk even when prepared properly. When consumed, the false morel's principal active agent, gyromitrin, is metabolized into the toxic compound monomethylhydrazine (MMH). The toxin affects the liver, central nervous system, and sometimes the kidneys. Symptoms of poisoning involve vomiting and diarrhea several hours after consumption, followed by dizziness, lethargy and headache. Severe cases may lead to delirium, coma and death after 5–7 days.

Taxonomy and naming

The fungus was first described by mycologist Christian Hendrik Persoon as "Helvella esculenta" in 1800, [Persoon CH (1800) "Comm. Schaeff. Icon. Pict.": 64] and gained its current accepted binomial name when the Swedish mycologist Elias Magnus Fries placed it in the genus "Gyromitra" in 1849. [Fries EM (1849) "Summa veg. Scand., Section Post". (Stockholm):p. 346] The genus name is derived from the Greek terms "gyros"/γυρος "round" and "mitra"/μιτρα "headband".cite book | author = Liddell, Henry George and Robert Scott | year = 1980 | title = A Greek-English Lexicon |edition=Abridged edition | publisher = Oxford University Press | location =Oxford | isbn= 0-19-910207-4] Its specific epithet is derived from the Latin "esculentus", "edible". [cite book | last = Simpson | first = D.P. | title = Cassell's Latin Dictionary | publisher = Cassell | year = 1979 | edition = 5th ed. | location = London | pages = p. 883 | isbn= 0-304-52257-0]

"Gyromitra esculenta" is a member of a group of fungi known as "false morels", named as such for their resemblance to the highly regarded true morels of the genus "Morchella". The grouping includes other species of the genus "Gyromitra", such as "G. infula" (elfin saddle), "G. caroliniana" (beefsteak mushroom) and "G. gigas" (snow morel). While some of these species contain little to no gyromitrin, many guidebooks recommend treating them all as poisonous, since their similar appearance and significant intraspecific variation can make reliable identification difficult. The more distantly related ascomycete mushrooms of the genus "Verpa", such as "V. bohemica" and "V. conica", are also known as false morels, early morels or thimble morels (and, like the "Gyromitra", are eaten by some and considered poisonous by others).Benjamin, p. 267]

The genus "Gyromitra" had been classically considered part of the family Helvellaceae, along with the similar-looking elfin saddles of the genus "Helvella". Analysis of the ribosomal DNA of many of the Pezizales showed "Gyromitra esculenta" and the other false morels to be only distantly related to the other members of the Helvellaceae and instead most closely related to the genus "Discina", forming a clade which also contains "Pseudorhizina" and "Hydnotrya". Thus the four genera are now included in the family Discinaceae. [cite journal |last=O'Donnell |first=Kerry|coauthors= Elizabeth Cigelnik, Nancy S. Weber and James M. Trappe |year=1997|title=Phylogenetic relationships among ascomycetous truffles and the true and false morels inferred from 18S and 28S ribosomal DNA sequence analysis |journal=Mycologia |volume=89 |issue=1 |pages=48–65 |doi=10.2307/3761172]

Description

Resembling a brain, the irregularly shaped cap may be up to 10 cm (4 in) high and 15 cm (6 in) wide. Initially smooth, it becomes progressively more wrinkled as it grows and ages. The cap colour may be various shades of reddish-, chestnut-, purplish-, bay-, dark or sometimes golden-brown. Specimens from California may have more reddish-brown caps. Attached to the cap at several points, the stipe is 3–6 cm (1.2–2.4 in) high and 2–3 cm (0.8–1.2 in) wide. "Gyromitra esculenta" has a solid stipe whereas those of true morels ("Morchella" spp.) are hollow. The smell can be pleasant and has been described as fruity, and the fungus is mild-tasting. The spore print is whitish, with transparent spores that are elliptical and 17–22 μm in length.cite book|last=Zeitlmayr|first= Linus|year=1976|title=Wild Mushrooms:An Illustrated Handbook|pages=p. 112|publisher=Garden City Press|location=Hertfordshire|isbn= 0-584-10324-7]

"G. esculenta" resembles the various species of true morel, although the latter are more symmetric and look more like pitted gray, tan, or brown sponges. Its cap is generally darker and larger.Ammirati, Joseph F. p. 121]

Distribution and habitat

"Gyromitra esculenta" grows on sandy soil in coniferous and occasionally deciduous woodlands. Among conifers it is mostly found under pines ("Pinus" spp.), but also sometimes aspen ("Populus" spp.). [cite book |title=How to Know the Non-Gilled Fleshy Fungi |author=Smith HV, Smith AH |year=1973 |publisher=Wm. C. Brown Co. |location=Dubuque, Il |isbn=0697048667] The hunting period is from April to July, earlier than for other species, and the fungus may even sprout up with the melting snow. It can be abundant in some years and rare in others. The mushroom is more commonly found in places where ground has been disturbed, such as openings, rivulets, washes, timber clearings, plowed openings, forest fire clearings, and roadsides.Nilsson S, Persson O.(1977) "Fungi of Northern Europe 1: Larger Fungi (Excluding Gill Fungi)". pp. 34–35. Penguin Books. isbn 0-14-063-005-8] Enthusiasts in Finland have been reported burying newspaper inoculated with the fungus in the ground in autumn and returning the following spring to collect mushrooms. [cite web |url=http://www.mushroomexpert.com/gyromitra_esculenta.html |title=Gyromitra esculenta |accessdate=2008-05-11 |author=Kuo M |date=2005, January |work=MushroomExpert.Com Web site |publisher=self]

Toxicity

Toxic reactions have been known for at least a hundred years. Experts speculated the reaction was more of an allergic one related to the consumer, or misidentification, rather than innate toxicity of the fungus, due to the wide range in effects seen. Some would suffer severely or perish while others exhibited no symptoms after eating similar amounts of mushrooms from a single dish. Yet others would be poisoned after eating "Gyromitra esculenta" for many years without ill-effects.Benjamin, p. 264] However, the fungus is now widely recognized as potentially deadly.Benjamin, p. 265]

"Gyromitra esculenta" contains the poison gyromitrin and although these mushrooms are only rarely involved in poisonings in either North America or Western Europe, intoxications are seen frequently in eastern Europe and Scandinavia.cite journal |author=Diaz JH |title=Syndromic diagnosis and management of confirmed mushroom poisonings |journal=Critical Care Medicine |volume=33 |issue=2 |pages=427–36 |year=2005 |pmid=15699849|doi=10.1097/01.CCM.0000153531.69448.49] A 1971 Polish study reported at the time that the species accounted for up to 23% of mushroom fatalities each year. Death rates have dropped since the mid-twentieth century; in Sweden poisoning is common but life-threatening poisonings have not been detected and there had not been a fatality reported over the 50 years from 1952 to 2002.

A lethal dose of gyromitrin has been estimated to be 10–30 mg/kg for children and 20–50 mg/kg in adults. These doses correspond to around 0.2–0.6 kg (6 oz.–1lb. 5oz. and 0.4–1 kg (13 oz.–2 lb. 3 oz. ) of fresh mushroom respectively. However, individual responses may vary and people who have ingested similar amounts may develop anything from minimal to severe toxicity. Evidence suggests that children are more severely affected, and it is unclear whether this is due to a larger weight per body mass ratio consumed or that differences in enzyme and metabolic activity are responsible. Although the amount of gyromitrin present can be significantly reduced through parboiling (leaching), it is a cumulative poison, and there is evidence that repeated consumption can increase risk of toxicity.

Geographical variation

Populations of "Gyromitra esculenta" appear to vary geographically in their toxicity. A French study has shown that mushrooms collected at higher altitudes have lower concentrations of toxin than those from lower elevations,Benjamin, p. 272] and there is some evidence that fungi west of the Rocky Mountains in North America contain less toxin than those to the east.Benjamin, p. 140] However, poisonings in the west have been reported, although they have been reported less frequently than the east. [cite journal |author=Balterowich L, Blaney B, White S |year=1996|title=Acute hepatotoxicity following ingestion of "Gyromitra esculenta"(false morel) mushrooms|journal= Journal of toxicology. Clinical toxicology |volume=34 |issue=5 | pages=602|doi=10.3109/15563659609028019 |doi_brokendate=2008-10-03]

Biochemistry

The identity of the toxic constituents eluded researchers until 1968, when "N"-methyl-"N"-formylhydrazone acetaldehyde, better known as gyromitrin, was isolated. [de icon cite journal |author=List PH, Luft P |title= [Gyromitrin, the poison of Gyromitra esculenta. 16. On the fungi contents] |language=German |journal=Archiv der Pharmazie und Berichte der Deutschen Pharmazeutischen Gesellschaft |volume=301 |issue=4 |pages=294–305 |year=1968 |pmid=5244383] Gyromitrin is a volatile water-soluble hydrazine compound metabolized in the body into monomethylhydrazine (MMH). MMH is a strongly reductive substance. [Benjamin, p. 268–69] Other "N"-methyl-"N"-formylhydrazone derivatives have been isolated in subsequent research, although they are present in smaller amounts. These other compounds may also produce monomethylhydrazine when metabolized. However, it remains unclear how much each contributes to the false morel's toxicity. [cite journal |author=Pyysalo H |title=Some new toxic compounds in false morels, Gyromitra esculenta |journal=Naturwissenschaften |volume=62 |issue=8 |pages=395 |year=1975 |pmid=1238907 |doi=10.1007/BF00625355]

The toxins react with pyridoxal-5-phosphate—the activated form of
pyridoxine—and form a hydrazone. This reduces production of the neurotransmitter GABA via decreased activity of glutamic acid decarboxylase, [cite journal |author=Cornish HH |title=The role of vitamin B6 in the toxicity of hydrazines |journal=Annals of the New York Academy of Sciences |volume=166 |issue=1 |pages=136–45 |year=1969 |pmid=5262010|doi=10.1111/j.1749-6632.1969.tb54264.x] producing the neurological symptoms. MMH also causes oxidative stress leading to methemoglobinemia. Additionally during the metabolism of MMH, "N"-methyl-"N"-formylhydrazine is produced; this then undergoes cytochrome p450 regulated oxidative metabolism which via reactive nitrosamide intermediates leads to formation of methyl radicals which lead to liver necrosis. [cite journal |author=Braun R, Greeff U, Netter KJ |title=Indications for nitrosamide formation from the mushroom poison gyromitrin by rat liver microsomes |journal=Xenobiotica |volume=10 |issue=7-8 |pages=557–64 |year=1980 |pmid=7445522] cite journal |author=Braun R, Greeff U, Netter KJ |title=Liver injury by the false morel poison gyromitrin |journal=Toxicology |volume=12 |issue=2 |pages=155–63 |year=1979 |pmid=473232|doi=10.1016/0300-483X(79)90042-8] Inhibition of diamine oxidase (histaminase) elevates histamine levels resulting in headaches, nausea, vomiting, and abdominal pain. [cite journal |author=Biegański T, Braun R, Kusche J |title=N-methyl-N-formylhydrazine: a toxic and mutagenic inhibitor of the intestinal diamine oxidase |journal=Agents and Actions |volume=14 |issue=3-4 |pages=351–5 |year=1984 |pmid=6428190 |doi=10.1007/BF01973825]

ymptoms

The symptoms of poisoning are typically gastrointestinal and neurological.cite journal |author=Karlson-Stiber C, Persson H |title=Cytotoxic fungi--an overview |journal=Toxicon |volume=42 |issue=4 |pages=339–49 |year=2003 |pmid=14505933 |doi=10.1016/S0041-0101(03)00238-1] The symptoms occur within 6–12 hours of consumption, although cases of more severe poisoning may present sooner—as little as 2 hours after ingestion. Initial symptoms are gastrointestinal, with sudden onset of nausea, vomiting, and watery diarrhea which may be bloodstained. Dehydration may develop if the vomiting or diarrhea is severe. Dizziness, lethargy, vertigo, tremor, ataxia, nystagmus, and headaches develop soon after; fever often occurs, a distinctive feature which does not develop after poisoning by other types of mushrooms. [Benjamin, p. 273] In most cases of poisoning, symptoms do not progress from these initial symptoms and patients recover after 2–6 days of illness.

In some cases there may be an asymptomatic phase following the initial symptoms which is then followed by more significant toxicity including kidney damage, [cite journal |author=Braun R, Kremer J, Rau H |title=Renal functional response to the mushroom poison gyromitrin |journal=Toxicology |volume=13 |issue=2 |pages=187–96 |year=1979 |pmid=42171] liver damage, and neurological dysfunction including seizures and coma.cite journal |author=Michelot D, Toth B |title=Poisoning by Gyromitra esculenta--a review |journal=Journal of applied toxicology |volume=11 |issue=4 |pages=235–43 |year=1991 |pmid=1939997|doi=10.1002/jat.2550110403] These signs usually develop within 1–3 days in serious cases. The patient develops jaundice and the liver and spleen become enlarged, in some cases blood sugar levels will rise (hyperglycemia) and then fall (hypoglycemia) and liver toxicity is seen. Additionally intravascular hemolysis causes destruction of red blood cells resulting in increase in free hemoglobin and hemoglobinuria which can leads to renal toxicity or renal failure. Methemoglobinemia may also occur in some cases. This is where higher than normal levels of methemoglobin, which is a form of hemoglobin that can not carry oxygen, are found in the blood. It causes the patient to become short of breath and cyanotic. [Benjamin, p. 274] Cases of severe poisoning may progress to a terminal neurological phase, with delirium, muscle fasciculations and seizures, and mydriasis progressing to coma, circulatory collapse, and respiratory arrest. [cite journal |author=Giusti GV, Carnevale A |title=A case of fatal poisoning by Gyromitra esculenta |journal=Archives of toxicology |volume=33 |issue=1 |pages=49–54 |year=1974 |pmid=4480349] Death may occur from five to seven days after consumption. [cite journal |author=Hanrahan JP, Gordon MA |title=Mushroom poisoning. Case reports and a review of therapy |journal=JAMA |volume=251 |issue=8 |pages=1057–61 |year=1984 |pmid=6420582|doi=10.1001/jama.251.8.1057]

Treatment

Treatment is mainly supportive; gastric decontamination with activated charcoal may be beneficial if medical attention is sought within a few hours of consumption. However, symptoms often take longer than this to develop and patients do not usually present for treatment until many hours after ingestion, thus limiting its effectiveness. [cite journal |author=Köppel C |title=Clinical symptomatology and management of mushroom poisoning |journal=Toxicon |volume=31 |issue=12 |pages=1513–40 |year=1993 |pmid=8146866|doi=10.1016/0041-0101(93)90337-I] Patients with severe vomiting or diarrhea can be rehydrated with intravenous fluids.cite journal |author=Lampe KF |title=Toxic fungi |journal=Annual Review of Pharmacology and Toxicology |volume=19|pages=85–104 |year=1979 |pmid=378111 |doi=10.1146/annurev.pa.19.040179.000505] Monitoring of biochemical parameters such as methemoglobin levels, electrolytes, liver and kidney function, urinalysis, and complete blood count is undertaken and any abnormalities are corrected. Dialysis can be used if kidney function is impaired or the kidneys are failing. Hemolysis may require a blood transfusion to replace the lost red blood cells, while methemoglobinemia is treated with intravenous methylene blue. [Benjamin, p. 276]

Also known as vitamin B6, pyridoxine can be used to counteract the inhibition by MMH on the pyridoxine-dependent step in the synthesis of the neurotransmitter GABA. Thus GABA synthesis can continue and symptoms are relieved. [cite journal |author=Wright AV, Niskanen A, Pyysalo H, Korpela H |title=Amelioration of toxic effects of ethylidene gyromitrin (false morel poison) with pyridoxine chloride|journal=Journal of Food Safety |volume=3|pages=199–203|year=1981 |doi=10.1111/j.1745-4565.1981.tb00422.x] Pyridoxine, which is only useful for the neurological symptoms and does not decrease hepatic toxicity, [cite journal |author=Toth B, Erickson J |title=Reversal of the toxicity of hydrazine an analogues by pyridoxine hydrochloride |journal=Toxicology |volume=7 |issue=1 |pages=31–36 |year=1977 |pmid=841582|doi=10.1016/0300-483X(77)90035-X] is given at a dose of 25 mg/kg; this can be repeated up to a maximum total of 15 to 30 g daily if symptoms do not improve. [cite journal |author=Kirklin JK, Watson M, Bondoc CC, Burke JF |title=Treatment of hydrazine-induced coma with pyridoxine |journal=New England Journal of Medicine |volume=294 |issue=17 |pages=938–9 |year=1976 |pmid=815813] Benzodiazepines are given to control seizures, as they modulate GABA receptors and may increase the effect of pyridoxine. Additionally MMH inhibits the chemical transformation of folic acid into its active form, folinic acid, this can be treated by folinic acid given at 20–200 mg daily.

Carcinogenicity

Consumption

Despite its recognized toxicity, "Gyromitra esculenta" is marketed and consumed in several countries or states in Europe and North America. It was previously consumed in Germany, with fungi picked in and exported from Poland. Once the extent of its toxicity became known, Germany and Switzerland discouraged consumption by prohibiting its sale.cite book | author= Bresinsky A, Besl H. | title = A Colour Atlas of Poisonous Fungi | year = 1990 | publisher = Wolfe Publishing | pages=62–68|isbn = 0-7234-1576-5] Similarly in Sweden, the Swedish National Food Administration warns it is not fit for human consumption, [sv iconcite web|last = Andersson|first = Christer| title = Stenmurklan - olämplig att äta| work = Livsmedelsverket (National Food Administration)| publisher = Swedish National Food Administration | year = 2007| url = http://www.slv.se/templates/SLV_Page.aspx?id=11600&epslanguage=SV| accessdate =2008-03-07] and restricts purchase of mushrooms to restaurants alone. [sv iconcite web|last = Andersson|first = Christer| title = Frågor och svar om stenmurkla| work = Livsmedelsverket (National Food Administration)| publisher = Swedish National Food Administration | year = 2007| url = http://www.slv.se/templates/SLV_Page.aspx?id=14181&epslanguage=SV| accessdate =2008-03-07] The mushroom is still highly regarded and consumed in Bulgaria, being sold in markets and picked for export there. [cite web | author = Drumeva-Dimcheva M, Gyosheva-Bogoeva M | title = Section One: Bulgaria's Biological Diversity - The Macromycetes Fungi of Bulgaria | work = Bulgaria's Biological Diversity: Conservation Status and Needs Assessment | publisher = Biodiversity Support Program (WWF, The Nature Conservancy, and World Resources Institute Consortium) | year = 1998 | url = http://www.worldwildlife.org/bsp/publications/europe/bulgaria/bulgaria1.html | accessdate = 2008-03-06] In some countries such as Spain, especially in the eastern Pyrenees, they are traditionally considered a delicacy, and many people report consuming them for many years with no ill effects. [cite web|url=http://www.elcargol.com/bolets.htm |title= Bolets|accessdate=2008-06-08 |publisher=Revista el cargol |year=2008 ] Despite this, the false morel is listed as hazardous in official mushroom lists published by the Catalan Government in Spain and sale for consumption is prohibited. [es iconcite web |url=http://www.boe.es/boe/dias/2004/02/06/pdfs/A05061-05065.pdf|format=PDF |title=Boletín Oficial del Estado número 32, pp. 5061–65 |accessdate=2008-06-08 |publisher=Ministerio de Sanidad y Consumo |date=2004-02-06] Selling and purchasing fresh false morels is legal according to Finnish law, where it is highly regarded. [cite journal |last=Härkonën |first=M |year=1998 |title=Uses of mushrooms by Finns and Karelians |journal=International Journal of circumpolar Health |volume=57 |issue=1 |pages=40–55 |pmid= 9567575] However, the mushrooms are required by law to be accompanied with a warning that they are poisonous and legally prescribed preparation instructions. [cite web | title =False morels must be accompanied by warning and handling instructions| publisher = The Finnish Food Safety Authority Evira | date = 11 May 2006 | url =http://www.evira.fi/portal/en/food/current_issues/?id=117|accessdate = 2008-03-04] False morels are also sold prepared and canned, in which case they are ready to be used. Official figures from the Finnish Ministry of Agriculture and Forestry report a total amount of false morels sold in Finland of 21.9 tonnes in 2006 and 32.7 tonnes, noted as being above average, in 2007. [fi iconCite book | author =Suomen Gallup Elintarviketieto Oy | title = MARSI 2007 — Luonnonmarjojen ja -sienien kauppaantulomäärät vuonna 2007 [Amounts of wild berries and mushrooms offered for sale in 2007] | pages =p. 10 | month = March | year = 2007 | publisher = Finnish Ministry of Agriculture and Forestry|location=Helsinki] In 2002, the Finnish Food Safety Authority estimated annual consumption of false morels to be hundreds of tonnes in plentiful years. [fi iconCite book| title = Riskiraportti – elintarvikkeiden ja Talousveden kemialliset vaarat [Risk report on toxins in food and tapwater] | pages =p. 38 | year =2002 | author = Finnish Food Safety Authority] Outside of Europe, "Gyromitra esculenta" is consumed in the Great Lakes region and some western states in the United States. [cite journal |last=Simons |first=DM |year=1971|title=The Mushroom Toxins |journal=Delaware Medical Journal |volume=43 |pages=177–87] In Finnish Cuisine, false morels may be cooked in an omelette, or gently sautéed in butter in a saucepan, flour and milk added to make a bechamel sauce, or pie filling. Alternately, more fluid can be added for a false morel soup. Typical condiments added for flavour include parsley, chives, dill and black pepper. [fi iconcite web |url=http://www.lapinkeittiomestarit.fi/sivut/teemat/toukokuu.htm#muhennos |title=Kevät on aikaa korvasienen ja väinönputken |publisher= Lapin Keittiömestarit|accessdate=2008-06-22] [cite book |title=North Atlantic Seafood: A Comprehensive Guide with Recipes|author=Davidson A |year=2003 |publisher=Ten Speed Press|isbn=1-58008-450-8 |pages=p. 361]

Preparation

Most of the gyromitrin must be removed to render false morels edible. The recommended procedure involves either first drying and then boiling the mushrooms, or boiling the fresh mushrooms directly.cite web| title =False Morel Fungi - poisonous when raw | publisher = The Finnish Food Safety Authority Evira | year = 2008 | url =http://www.evira.fi/portal/en/food/information_on_food/false_morel_fungi/ | accessdate = 2008-03-04] To prepare fresh mushroom it is recommended that they are cut into small pieces and boiled twice in copious amounts of water, at least three parts water to one part chopped mushrooms, for at least five minutes, after each boiling the mushroom should be rinsed thoroughly in clean water. Each round of parboiling reduces the gyromitrin contents to a tenth.cite journal |author=Pyysalo H, Niskanen A |title=On the occurrence of N-methyl-N-formylhydrazones in fresh and processed false morel, Gyromitra esculenta |journal=Journal of Agricultural and Food Chemistry |volume=25 |issue=3 |pages=644–47 |year=1977 |pmid=558239 |doi=10.1021/jf60211a006] The gyromitrin is leached into the water where it will remain, therefore the parboiling water must be discarded and replaced with fresh water after each round of boiling. Drying the mushrooms can also reduce the concentration of gyromitrin; ten days of open air desiccation leads to the loss of 90% of gyromitrin. However it is still recommended that the mushroom be boiled after drying.

MMH boils at convert|87.5|°C|°F|sigfig=2 and thus readily vaporizes into the air when water containing fresh false morels is boiled.cite journal |author=Leathem AM, Dorran TJ |title=Poisoning due to raw Gyromitra esculenta (false morels) west of the Rockies |journal=Canadian Journal of Emergency Medical Care |volume=9 |issue=2 |pages=127–30 |year=2007 |pmid=17391587] Poorly ventilated spaces allow vapor to accumulate, resulting in gyromitrin poisoning. If boiling the mushrooms indoors, care should be taken to ensure adequate ventilation, and, if symptoms of gyromitrin poisoning appear, immediately seek fresh air. [Benjamin, p. 269] Even after boiling, small amounts of gyromitrin remain in the mushrooms. Given the possibility of accumulation of toxins, repeated consumption is not recommended. [Benjamin, p. 278]

Prospects for cultivation

Despite its toxicity, "Gyromitra esculenta" is clearly highly regarded gastronomically by many. Toxin levels corroborate well between mycelium and fruiting bodies, and strains with much lower concentrations of gyromitrin have been discovered. Furthermore, the fungus has been successfully grown to fruiting in culture. [cite journal |author=List PH, Sundermann G |year=1974|title=Achtung! Frühjahrslorcheln |journal=Deutsche Apotheker Zeitung |volume=114 |pages=331–32] Thus there is scope for future research into cultivation of safer strains. [Benjamin, p. 279]

References

External links

* [http://botit.botany.wisc.edu/toms_fungi/may2002.html "Gyromitra esculenta", one of the false morels"]
* [http://www.dlc.fi/~marianna/gourmet/morel.htm#instrc Official Finnish instructions for the processing of false morels]

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Gyromitra esculenta — Gyromitra esculenta … Wikipédia en Français
Gyromitra esculenta — Gyromitra esculenta … Wikipédia en Français
Gyromitra esculenta — Frühjahrslorchel Frühjahrslorchel (Gyromitra esculenta) Systematik Abteilung: Echte Schlauchpilze (Euascomycota) … Deutsch Wikipedia
Gyromitra esculenta — Bonete o Falsa Colmenilla Gyromitra esc … Wikipedia Español
Gyromitra esculenta — Turban top Tur ban top , n. (Bot.) A kind of fungus with an irregularly wrinkled, somewhat globular pileus ({Helvella esculenta} syn. {Gyromitra esculenta}.). [1913 Webster] … The Collaborative International Dictionary of English
Gyromitra esculenta — El hongo bonete o falsa colmenilla (Gyromitra esculenta) pertenece a la familia Helvellacea y es tóxico. Es similar en apariencia a las colmenillas (Morchella spp.), de donde viene uno de sus nombres; el riesgo de confundirlo con una de éstas,… … Enciclopedia Universal
Gyromitra esculenta — noun a poisonous gyromitra; the surface of the fertile body is smooth at first and becomes progressively undulating and wrinkled (but never truly pitted); color varies from dull yellow to brown • Syn: ↑brain mushroom, ↑beefsteak morel • Hypernyms … Useful english dictionary
Gyromitra esculenta — A species of mushroom that may produce a monomethylhydrazine toxin that causes nausea, diarrhea, and other symptoms; in severe cases death may occur. SYN: Helvella esculenta … Medical dictionary
Gyromitra esculenta — Gyro̱|mi|tra es|culẹnta [zu gr. γυ̃ρος = Kreis u. gr. μιτρα = Hauptbinde, Kopfbedeckung; ↑esculentus] w; : Frühjahrslorchel, Stockmorchel, Pilz, der verschiedene, durch Abkochen fast immer zerstörbare Gifte (vor allem die ↑Helvellasäure) enthält … Das Wörterbuch medizinischer Fachausdrücke
Gyromitra — esculenta Gyromitra esculenta … Wikipédia en Français

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