Gyromitra esculenta
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2008-07-15T01:06:23Z
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{{Taxobox
| name = False Morel
| image = Frühjahrslorchel.JPG
| regnum = [[Fungus|Fungi]]
| phylum = [[Ascomycota]]
| classis = [[Ascomycetes]]
| ordo = [[Pezizales]]
| familia = [[Discinaceae]]
| genus = ''[[Gyromitra]]''
| species = '''''G. esculenta'''''
| binomial = ''Gyromitra esculenta''
| binomial_authority = ([[Christian Hendrik Persoon|Pers.]] ex [[Christian Hendrik Persoon|Pers.]]) [[Elias Magnus Fries|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 [[Ascomycota|ascomycete]] fungus from the genus ''[[Gyromitra]]'', widely distributed across Europe and North America and one of several species of fungi known as [[false morel]]s. It normally sprouts in sandy soils under [[coniferous]] trees, in spring and early summer. The [[Ascocarp|fruiting body]], or mushroom, is an irregular brain-shaped [[Pileus (mycology)|cap]] dark brown in colour which can reach 10 [[centimetre|cm]] (4 [[inch|in]]) high and 15 cm (6 in) wide, perched on a stout white [[stipe (mycology)|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 (North America)|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 [[omelette]]s, soups, or [[sautée]]d in [[Cuisine of Finland|Finnish cuisine]]. Once popular in the [[Pyrenees]], it is now prohibited from sale for consumption in Spain.
Although it is still commonly consumed after [[parboil]]ing, recent evidence suggests that even this procedure may not make the fungus entirely safe;<ref name="dart">{{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}}</ref> 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 [[hepatotoxicity|liver]], [[neurotoxicity|central nervous system]], and sometimes the [[Nephrotoxicity|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,<ref>Persoon CH (1800) ''Comm. Schaeff. Icon. Pict.'': 64</ref> and gained its current accepted [[Binomial nomenclature|binomial]] name when the Swedish mycologist [[Elias Magnus Fries]] placed it in the genus ''Gyromitra'' in 1849.<ref>Fries EM (1849) ''Summa veg. Scand., Section Post''. (Stockholm):p. 346</ref> The genus name is derived from the [[Ancient Greek|Greek]] terms ''gyros''/γυρος "round" and ''mitra''/μιτρα "headband".<ref name="Liddell 1980">{{cite book | author = [[Henry George Liddell|Liddell, Henry George]] and [[Robert Scott (philologist)|Robert Scott]] | year = 1980 | title = [[A Greek-English Lexicon]] |edition=Abridged edition | publisher = Oxford University Press | location =Oxford | isbn= 0-19-910207-4}}</ref> Its specific epithet is derived from the [[Latin]] ''esculentus'', "edible".<ref>{{cite book | last = Simpson | first = D.P. | title = Cassell's Latin Dictionary | publisher = Cassell | date = 1979 | edition = 5th ed. | location = London | pages = p. 883 | isbn= 0-304-52257-0}}</ref>
It is known by a variety of common descriptive names such as ''brain mushroom'',<ref name="arora86">{{cite book |last=Arora |first=David|authorlink=David Arora |year=1986 |title=Mushrooms demystified: a comprehensive guide to the fleshy fungi |edition=2nd ed. |location=Berkeley |publisher=Ten Speed Press |isbn=0-89815-169-4| pages=pp. 801–02}}</ref> ''turban fungus'',<ref name=Lamaison05/> ''elephant ears'',<ref>{{cite journal |last=Dearness |first=J |year=1924|title=''Gyromitra'' poisoning |journal=Mycologia |volume=16|pages=199 |doi=10.2307/3753381}}</ref> or ''beefsteak mushroom/morel''.<ref name=Ammir85>{{cite book |last=Ammirati |first=Joseph F.|coauthors= James A Traquair and Paul A Horgen |title=Poisonous mushrooms of the northern United States and Canada |year=1985 |publisher=University of Minnesota Press |location=Minneapolis |isbn=0-8166-1407-5 |pages=p. 122}}</ref> Dating from the 19th century, the German term ''lorchel'' is a result of the older ''lorche'', itself from the 18th century [[Low German]] ''Lorken'', aligning with the similar sounding (and similar looking) ''morchel''.<ref>{{cite book |last= |first= |authorlink= |coauthors= |editor= |others= |title=Duden – Das Herkunftswörterbuch – Etymologie der deutschen Sprache |year=2001|publisher=Dudenverlag |location= |language=[[German language|German]] |isbn= 3411040742}}</ref><ref>{{cite book | last = North| first = Pamela | year = 1967 | title = Poisonous Plants and Fungi in colour | publisher = Blandford Press & Pharmacological Society of Great Britain |pages=p. 109|oclc=955264}}</ref> The Finnish name ''Korvasieni'' is derived from the terms ''korva'' "ear", and ''sieni'' "mushroom/fungus",<ref>{{cite web| author = Parker PM| title =korva | work = Webster's Online Dictionary - The Rosetta Edition| publisher = Webster's Online Dictionary| date = 2008| url = http://www.websters-dictionary-online.org/translation/finnish/korva| accessdate =2008-03-07}}</ref><ref>{{cite web| author = Parker PM| title =sieni| work = Webster's Online Dictionary - The Rosetta Edition| publisher = Webster's Online Dictionary| date = 2008| url = http://www.websters-dictionary-online.org/translation/finnish/sieni| accessdate =2008-03-07}}</ref> while the Swedish ''Stenmurkla'' is ''Sten'' "stone" and ''murkla'' "morel".<ref>{{cite web| author = Parker PM| title =sten| work = Webster's Online Dictionary - The Rosetta Edition| publisher = Webster's Online Dictionary| date = 2008| url = http://www.websters-dictionary-online.org/translation/swedish/sten| accessdate =2008-03-07}}</ref><ref>{{cite web| author = Parker PM| title =murkla| work = Webster's Online Dictionary - The Rosetta Edition| publisher = Webster's Online Dictionary| date = 2008| url = http://www.websters-dictionary-online.org/translation/swedish/murkla| accessdate =2008-03-07}}</ref>
''Gyromitra esculenta'' is a member of a group of fungi known as "[[false morel]]s", named as such for their resemblance to the highly regarded true morels of the genus ''[[Morel|Morchella]]''. The grouping includes other species of the genus ''Gyromitra'', such as ''[[Gyromitra infula|G. infula]]'' (elfin saddle), ''[[Gyromitra caroliniana|G. caroliniana]]'' (beefsteak mushroom) and ''[[Gyromitra gigas|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).<ref name=Benj267>Benjamin, p. 267</ref>
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 [[ribosome|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]].<ref>{{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}}</ref>
==Description==
[[Image:Giftlorchel.jpg|left|thumb|A younger specimen with a less wrinkled cap]]
Resembling a brain, the irregularly shaped [[pileus (mycology)|cap]] may be up to 10 [[centimetre|cm]] (4 [[inch|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.<ref name="arora86"/> Attached to the cap at several points, the [[stipe (mycology)|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.<ref name="Nilper77"/> 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 [[micrometre|μm]] in length.<ref name ="Zeitl">{{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}}</ref>
''G. esculenta'' resembles the various species of true morel, although the latter are more symmetric and look more like pitted gray, tan, or brown [[sponge]]s. Its cap is generally darker and larger.<ref name=Ammir121>Ammirati, Joseph F. p. 121</ref>
==Distribution and habitat==
''Gyromitra esculenta'' grows on sandy soil in [[Temperate coniferous forest|coniferous]] and occasionally [[Temperate deciduous forest|deciduous woodlands]]. Among conifers it is mostly found under pines (''[[pine|Pinus]]'' spp.), but also sometimes aspen (''[[Populus]]'' spp.).<ref>{{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}}</ref> The hunting period is from April to July, earlier than for other species, and the fungus may even sprout up with the melting snow.<ref name="arora86"/> 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.<ref name="Nilper77">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</ref> 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.<ref>{{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}}</ref>
Although more abundant in [[montane]] and northern coniferous woodlands such as the [[Sierra Nevada (U.S.)|Sierra Nevada]] and the [[Cascade Range]] in northwestern North America, ''Gyromitra esculenta'' is found widely across the continent,<ref name="arora86"/> as far south as [[Mexico]].<ref>{{cite journal |last=Medel |first=Rosario|year=2005|title=A review of the genus ''Gyromitra'' (Ascomycota, Pezizales, Discinaceae) in Mexico |journal=Mycotaxon |volume=94|pages=103–10}}</ref> It is also common in Central Europe, less abundant in the east, and more in montane areas than lowlands.<ref name=Lamaison05>{{cite book |title=The Great Encyclopedia of Mushrooms |last=Lamaison |first=Jean-Louis |coauthors=Polese, Jean-Marie |year=2005 |publisher=Könemann |isbn=3-8331-1239-5|pages=p. 230}}</ref> It has been recorded from [[Northern Ireland]],<ref>{{cite web |title = Northern Ireland's Herbarium Specimens| publisher = Northern Ireland Fungus Group | date=2007| url= http://www.nifg.org.uk/herbarium.htm| accessdate =2008-03-06}}</ref> from [[Uşak Province]] in Western Turkey,<ref>{{cite journal |author=Türkoglu A, Alli H, Iṣiloğlu M, , Yağiz D, Gezer K |year=2008|month=February|title=Macrofungal diversity of Uşak province in Turkey |journal=Mycotaxon |volume=103|pages=1–11 |url=http://egitim.selcuk.edu.tr/fen/yagiz/pdf/mycotaxon08-002.pdf|format=PDF|accessdate=2008-03-07 }}</ref> and from the vicinity of [[Kaş]] in the [[Antalya Province]] of Turkey's southern coast.<ref name=Gez00>{{cite journal |author=Gezer K |year=2000|title=Contributions to the Macrofungi Flora of Antalya Province |journal=Turkish Journal of Botany |volume=24|issue=5|pages=293–98|url=http://mistug.tubitak.gov.tr/bdyim/abs.php?dergi=bot&rak=97069|accessdate=2008-02-16}}</ref>
==Toxicity==
[[Image:False morels for sale - don't touch.jpg|thumb|For sale with warning sign, [[Market Square, Helsinki]]]]
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.<ref name=Benj264>Benjamin, p. 264</ref> However, the fungus is now widely recognized as potentially deadly.<ref name=Benj265>Benjamin, p. 265</ref>
''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]].<ref name="diaz">{{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}}</ref> A 1971 [[Poland|Polish]] study reported at the time that the species accounted for up to 23% of mushroom fatalities each year.<ref name="Lampe"/> 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.<ref name="Karlson"/>
A lethal dose of gyromitrin has been estimated to be 10–30 [[milligram|mg]]/[[kilogram|kg]] for children and 20–50 mg/kg in adults. These doses correspond to around 0.2–0.6 kg (0.4–1.3 [[Pound (mass)|lb]]) and 0.4–1 kg (0.8–2.2 lb) of fresh mushroom respectively.<ref name="Michelot"/> However, individual responses may vary and people who have ingested similar amounts may develop anything from minimal to severe toxicity.<ref name="coulet"/> 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.<ref name=Benj272/> Although the amount of gyromitrin present can be significantly reduced through parboiling ([[Leaching (chemical science)|leaching]]), it is a cumulative poison, and there is evidence that repeated consumption can increase risk of toxicity.<ref name="coulet"/>
===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,<ref name=Benj272>Benjamin, p. 272</ref> and there is some evidence that fungi west of the [[Rocky Mountains]] in North America contain less toxin than those to the east.<ref name=Benj140>Benjamin, p. 140</ref> However, poisonings in the west have been reported,<ref name="Leathem"/> although they have been reported less frequently than the east.<ref>{{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}}</ref>
===Biochemistry===
[[Image:Methylhydrazine-3D-balls.png|thumb|left|[[Monomethylhydrazine|MMH]] ([[Carbon|C]][[Hydrogen|H]]<sub>3</sub>[[Nitrogen|N]]<sub>2</sub>[[Hydrogen|H]]<sub>3</sub>), a toxic metabolite also used in [[rocket fuel]]]]
The identity of the toxic constituents eluded researchers until 1968, when ''N''-methyl-''N''-formylhydrazone acetaldehyde, better known as [[gyromitrin]], was isolated.<ref>{{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}}</ref> Gyromitrin is a [[Volatility (chemistry)|volatile]] [[solubility|water-soluble]] [[hydrazine]] compound metabolized in the body into [[monomethylhydrazine]] (MMH). MMH is a strongly [[redox|reductive]] substance.<ref>Benjamin, p. 268-69</ref> 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.<ref>{{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}}</ref>
The toxins react with pyridoxal-5-phosphate—the activated form of
[[pyridoxine]]—and form a hydrazone. This reduces production of the neurotransmitter [[Gamma-aminobutyric acid|GABA]] via decreased activity of [[glutamic acid decarboxylase]],<ref>{{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}}</ref> producing the neurological symptoms. MMH also causes oxidative stress leading to [[methemoglobinemia]].<ref name="Michelot"/> 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.<ref>{{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}}</ref><ref name="Braun">{{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}}</ref> Inhibition of [[diamine oxidase]] (histaminase) elevates [[histamine]] levels resulting in headaches, nausea, vomiting, and abdominal pain.<ref>{{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}}</ref>
===Symptoms===
The symptoms of poisoning are typically [[gastrointestinal]] and [[neurological]].<ref name="Karlson">{{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}}</ref> 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 (medical)|vertigo]], tremor, [[ataxia]], [[nystagmus]], and headaches develop soon after;<ref name="Karlson"/> [[fever]] often occurs, a distinctive feature which does not develop after poisoning by other types of mushrooms.<ref>Benjamin, p. 273</ref> In most cases of poisoning, symptoms do not progress from these initial symptoms and patients recover after 2–6 days of illness.<ref name="Lampe"/>
In some cases there may be an [[asymptomatic]] phase following the initial symptoms which is then followed by more significant toxicity including [[nephrotoxicity|kidney damage]],<ref>{{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}}</ref> [[Hepatotoxicity|liver damage]], and [[neurotoxicity|neurological dysfunction]] including seizures and coma.<ref name="Michelot">{{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}}</ref> These signs usually develop within 1–3 days in serious cases.<ref name="Karlson"/> 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 [[cyanosis|cyanotic]].<ref>Benjamin, p. 274</ref> 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]].<ref>{{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}}</ref> Death may occur from five to seven days after consumption.<ref>{{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}}</ref>
===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.<ref>{{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}}</ref> Patients with severe vomiting or diarrhea can be rehydrated with [[Intravenous therapy|intravenous]] fluids.<ref name="Lampe">{{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}}</ref> 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. [[Hemodialysis|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]].<ref>Benjamin, p. 276</ref>
Also known as [[vitamin B6]], pyridoxine can be used to counteract the [[Enzyme inhibitor|inhibition]] by MMH on the pyridoxine-dependent step in the synthesis of the [[neurotransmitter]] [[Gamma-aminobutyric acid|GABA]]. Thus GABA synthesis can continue and symptoms are relieved.<ref>{{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}}</ref> Pyridoxine, which is only useful for the neurological symptoms and does not decrease hepatic toxicity,<ref name="Braun"/><ref>{{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}}</ref> is given at a dose of 25 [[milligram|mg]]/[[kilogram|kg]]; this can be repeated up to a maximum total of 15 to 30 [[gram|g]] daily if symptoms do not improve.<ref>{{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}}</ref> [[Benzodiazepine]]s 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.<ref name="Michelot"/>
===Carcinogenicity===
At least 11 different hydrazines have been isolated from ''Gyromitra esculenta''. Many of these have been shown to be actively [[carcinogen]]ic and highly [[mutagen]]ic in standard assays and produce tumors in experimental animals.<ref name="toth">{{cite journal |author=Toth B, Nagel D |title=Tumors induced in mice by N-methyl-N-formylhydrazine of the false morel Gyromitra esculenta |journal=Journal of the National Cancer Institute |volume=60 |issue=1 |pages=201–04 |year=1978 |pmid=628017}}</ref><ref>{{cite journal |author=Toth B, Smith JW, Patil KD |title=Cancer induction in mice with acetaldehyde methylformylhydrazone of the false morel mushroom |journal=Journal of the National Cancer Institute |volume=67 |issue=4 |pages=881–87 |year=1981 |pmid=6944556}}</ref><ref>{{cite journal |author=Toth B, Patil K, Pyysalo H, Stessman C, Gannett P |title=Cancer induction in mice by feeding the raw false morel mushroom Gyromitra esculenta |journal=Cancer Research |volume=52 |issue=8 |pages=2279–84 |year=1992 |pmid=1559231}}</ref><ref>{{cite journal |author=Toth B, Shimizu H |title=Methylhydrazine tumorigenesis in Syrian golden hamsters and the morphology of malignant histiocytomas |journal=Cancer Research |volume=33 |issue=11 |pages=2744–53 |year=1973 |pmid=4355982}}</ref><ref>{{cite journal |author=Toth B, Patil K, Erickson J, Kupper R |title=False morel mushroom Gyromitra esculenta toxin: N-methyl-N-formylhdrazine carcinogenesis in mice |journal=Mycopathologia |volume=68 |issue=2 |pages=121–28 |year=1979 |pmid=573857 |doi=10.1007/BF00441091}}</ref> The toxins may be cumulative<ref name="coulet">{{cite journal |author=Coulet M, Guillot J |title=Poisoning by Gyromitra : a possible mechanism |journal=Medical Hypotheses |volume=8 |issue=4 |pages=325–34 |year=1982 |pmid=7099057|doi=10.1016/0306-9877(82)90024-X}}</ref> and even small amounts may have a carcinogenic effect.<ref>Benjamin, p. 128-29</ref> Although ''Gyromitra esculenta'' has not been observed to cause cancer in humans,<ref name="Bresinsky"/> it is possible there is a carcinogenic risk for people who ingest these types of mushrooms.<ref name="toth"/> It is not known if the potential carcinogens can be completely removed by parboiling.<ref name="dart"/>
==Consumption==
[[Image:False morels for sale in Helsinki 2.jpg|thumb|right|For sale in [[Helsinki]]]]
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.<ref name ="Zeitl"/><ref name="Bresinsky">{{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}}</ref> Similarly in [[Sweden]], the [[Swedish National Food Administration]] warns it is not fit for human consumption,<ref>{{sv icon}}{{cite web|last = Andersson|first = Christer| title = Stenmurklan - olämplig att äta| work = Livsmedelsverket (National Food Administration)| publisher = Swedish National Food Administration | date = 2007| url = http://www.slv.se/templates/SLV_Page.aspx?id=11600&epslanguage=SV| accessdate =2008-03-07}}</ref> and restricts purchase of mushrooms to restaurants alone.<ref>{{sv icon}}{{cite web|last = Andersson|first = Christer| title = Frågor och svar om stenmurkla| work = Livsmedelsverket (National Food Administration)| publisher = Swedish National Food Administration | date = 2007| url = http://www.slv.se/templates/SLV_Page.aspx?id=14181&epslanguage=SV| accessdate =2008-03-07}}</ref> The mushroom is still highly regarded and consumed in [[Bulgaria]], being sold in markets and picked for export there.<ref>{{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) | date = 1998 | url = http://www.worldwildlife.org/bsp/publications/europe/bulgaria/bulgaria1.html | accessdate = 2008-03-06}}</ref> 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.<ref>{{cite web|url=http://www.elcargol.com/bolets.htm |title= Bolets|accessdate=2008-06-08 |publisher=Revista el cargol |date=2008 }}</ref> 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.<ref>{{es icon}}{{cite 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}}</ref> Selling and purchasing fresh false morels is legal according to Finnish law, where it is highly regarded.<ref>{{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}}</ref> However, the mushrooms are required by law to be accompanied with a warning that they are poisonous and legally prescribed preparation instructions.<ref>{{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}}</ref> 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 [[tonne]]s in 2006 and 32.7 tonnes, noted as being above average, in 2007.<ref>{{fi icon}}{{Cite 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 | year =2007 | date = March | publisher = Finnish Ministry of Agriculture and Forestry|location=Helsinki}}</ref> In 2002, the Finnish Food Safety Authority estimated annual consumption of false morels to be hundreds of tonnes in plentiful years.<ref>{{fi icon}}{{Cite 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}}</ref> Outside of Europe, ''Gyromitra esculenta'' is consumed in the [[Great Lakes]] region and some western states in the United States.<ref>{{cite journal |last=Simons |first=DM |year=1971|title=The Mushroom Toxins |journal=Delaware Medical Journal |volume=43 |pages=177–87}}</ref>
[[Image:False morel sauce with vegetables.jpg|left|thumb|Cooked in a cream sauce]]
In [[Cuisine of Finland|Finnish Cuisine]], false morels may be cooked in an [[omelette]], or gently [[sautée]]d 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]].<ref>{{fi icon}}{{cite 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}}</ref><ref>{{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}}</ref>
===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.<ref name="EVIRA">{{cite web| title =False Morel Fungi - poisonous when raw | work = | publisher = The Finnish Food Safety Authority Evira | date = 2008 | url =http://www.evira.fi/portal/en/food/information_on_food/false_morel_fungi/ | format = | doi = | accessdate = 2008-03-04}}</ref> 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.<ref name="EVIRA"/> Each round of [[parboiling]] reduces the gyromitrin contents to a tenth.<ref name="Pyysalo">{{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}}</ref> 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 [[unit operation|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.<ref name="coulet"/> However it is still recommended that the mushroom be boiled after drying.<ref name="EVIRA"/>
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.<ref name="Leathem">{{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}}</ref> 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.<ref>Benjamin, p. 269</ref> Even after boiling, small amounts of gyromitrin remain in the mushrooms. Given the possibility of accumulation of toxins, repeated consumption is not recommended.<ref>Benjamin, p. 278</ref>
===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.<ref>{{cite journal |author=List PH, Sundermann G |year=1974|title=Achtung! Frühjahrslorcheln |journal=Deutsche Apotheker Zeitung |volume=114 |pages=331–32}}</ref> Thus there is scope for future research into cultivation of safer strains.<ref>Benjamin, p. 279</ref>
== References ==
{{refbegin}}
;General
*{{cite book |last=Benjamin| first= Denis R. |title=Mushrooms: poisons and panaceas — a handbook for naturalists, mycologists and physicians |publisher=WH Freeman and Company| location=New York |year=1995| isbn=0-7167-2600-9}}
;Specific
{{refend}}
{{Reflist|2}}
== External links ==
{{commons}}
*[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]
{{featured article}}
[[Category:Ascomycota]]
[[Category:Deadly fungi]]
[[Category:Finnish cuisine]]
[[Category:Fungi of Finland]]
[[Category:Fungi of North America]]
[[Category:Fungi of Europe]]
[[ca:Bolet de greix]]
[[cs:Ucháč obecný]]
[[de:Frühjahrslorchel]]
[[et:Kevadkogrits]]
[[es:Gyromitra esculenta]]
[[fr:Gyromitre]]
[[it:Gyromitra esculenta]]
[[lt:Valgomasis bobausis]]
[[ja:シャグマアミガサタケ]]
[[pl:Piestrzenica kasztanowata]]
[[ru:Строчок]]
[[fi:Korvasieni]]
[[sv:Stenmurkla]]
[[uk:Строчок звичайний]]