Amatoxin

{{Short description|Family of toxins}} {{cs1 config|name-list-style=vanc}}'''Amatoxins''' are a subgroup of at least nine related cyclic peptide toxins found in three genera of deadly poisonous mushrooms (''Amanita'', ''Galerina'' and ''Lepiota'') and one species of the genus ''Pholiotina''.<ref>{{cite journal | vauthors = Diaz JH | title = Amatoxin-Containing Mushroom Poisonings: Species, Toxidromes, Treatments, and Outcomes | journal = Wilderness & Environmental Medicine | volume = 29 | issue = 1 | pages = 111–118 | date = March 2018 | pmid = 29325729 | doi = 10.1016/j.wem.2017.10.002 | doi-access = free }}</ref> Amatoxins are very potent, since as little as half a mushroom cap can cause severe liver injury if swallowed.

== Structure == thumb|The backbone structure (black) is the same in all the amatoxins and five variable groups (red) determine the specific compound. The compounds have a similar structure, that of eight amino-acid residues arranged in a conserved macrobicyclic motif (an overall pentacyclic structure when counting the rings inherent in the proline and tryptophan-derived residues); they were isolated in 1941 by Heinrich O. Wieland and Rudolf Hallermayer.<ref name="Litten_1975">{{cite journal | vauthors = Litten W | title = The most poisonous mushrooms | journal = Scientific American | volume = 232 | issue = 3 | pages = 90–101 | date = March 1975 | pmid = 1114308 | doi = 10.1038/scientificamerican0375-90 | bibcode = 1975SciAm.232c..90L }}</ref> All amatoxins are cyclic peptides that are synthesized as 35-amino-acid proproteins, from which the final eight amino acids are cleaved by a prolyl oligopeptidase.<ref>{{cite journal | vauthors = Hallen HE, Luo H, Scott-Craig JS, Walton JD | title = Gene family encoding the major toxins of lethal Amanita mushrooms | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 104 | issue = 48 | pages = 19097–19101 | date = November 2007 | pmid = 18025465 | pmc = 2141914 | doi = 10.1073/pnas.0707340104 | doi-access = free | bibcode = 2007PNAS..10419097H }}</ref> The schematic amino acid sequence of amatoxins is Ile-Trp-Gly-Ile-Gly-Cys-Asn-Pro with cross-linking between Trp and Cys via the sulfoxide (S=O) moiety and hydroxylation in variants of the molecule; enzymes for these processing steps remain unknown.

There are ten amatoxins {{asof|1993|lc=y}}:<ref>{{cite journal | vauthors = Baumann K, Münter K, Faulstich H | title = Identification of structural features involved in binding of alpha-amanitin to a monoclonal antibody | journal = Biochemistry | volume = 32 | issue = 15 | pages = 4043–4050 | date = April 1993 | pmid = 8471612 | doi = 10.1021/bi00066a027 }}</ref>

{| class="wikitable" |- ! Name ! R1 ! R2 ! R3 ! R4 ! R5 |- | α-Amanitin | OH | OH | NH2 | OH | OH |- | β-Amanitin | OH | OH | OH | OH | OH |- | γ-Amanitin | OH | H | NH2 | OH | OH |- | ε-Amanitin | OH | H | OH | OH | OH |- | Amanullin | H | H | NH2 | OH | OH |- | Amanullinic acid | H | H | OH | OH | OH |- | Amaninamide | OH | OH | NH2 | H | OH |- | Amanin | OH | OH | OH | H | OH |- | Proamanullin | H | H | NH2 | OH | H |}

δ-Amanitin has been reported, but its chemical structure has not been determined.

=== Family relations === {{Infobox protein family |Name=Amanitin/phalloidin precursor |InterPro=IPR027582 |Symbol=Amanitin/phalloidin }} Amanitin is very closely related to phalloidins, which are bicyclic 7-residue toxins. They both are part of the MSDIN protein family, so named after the highly conserved 5-amino-acid sequence in the preproteins. A 2014 research study determined that there exists a significant number of uncharacterized MSDIN sequences in ''Amanita'' genomes.<ref>{{cite journal | vauthors = Li P, Deng W, Li T | title = The molecular diversity of toxin gene families in lethal Amanita mushrooms | journal = Toxicon | volume = 83 | pages = 59–68 | date = June 2014 | pmid = 24613547 | doi = 10.1016/j.toxicon.2014.02.020 | bibcode = 2014Txcn...83...59L }}</ref>

==Mechanism== Amatoxins are potent and selective inhibitors of RNA polymerase II (RNA Pol II), a vital enzyme in the synthesis of messenger RNA (mRNA), microRNA, and small nuclear RNA (snRNA). Without mRNA, which is the template for protein synthesis, cell metabolism stops and apoptosis ensues.<ref name="Karlson-Stiber_2003">{{cite journal | vauthors = Karlson-Stiber C, Persson H | title = Cytotoxic fungi--an overview | journal = Toxicon | volume = 42 | issue = 4 | pages = 339–349 | date = September 2003 | pmid = 14505933 | doi = 10.1016/S0041-0101(03)00238-1 | bibcode = 2003Txcn...42..339K }}</ref> The RNA polymerase of ''Amanita phalloides'' has mutations that make it insensitive to the effects of amatoxins; thus, the mushroom does not poison itself.<ref name="Horgen_1978">{{cite journal | vauthors = Horgen PA, Vaisius AC, Ammirati JF | title = The insensitivity of mushroom nuclear RNA polymerase activity to inhibition by amatoxins | journal = Archives of Microbiology | volume = 118 | issue = 3 | pages = 317–319 | date = September 1978 | pmid = 567964 | doi = 10.1007/BF00429124 | bibcode = 1978ArMic.118..317H | s2cid = 37127957 }}</ref>

Amatoxins are able to travel through the bloodstream to reach the organs in the body. While these compounds can damage many organs, damage to the liver and heart result in fatalities. At the molecular level, amatoxins cause damage to cells of these organs by causing perforations in the plasma membranes resulting in misplaced organelles that are normally in the cytoplasm to be found in the extracellular matrix.<ref>{{cite journal | vauthors = Meldolesi J, Pelosi G, Brunelli A, Genovese E | title = Electron microscopic studies on the effects of amanitin in mice: liver and heart lesions | journal = Virchows Archiv für Pathologische Anatomie und Physiologie und für Klinische Medizin | volume = 342 | issue = 3 | pages = 221–235 | date = June 1967 | pmid = 5301504 | doi = 10.1007/bf00960591 | s2cid = 12556291 }}</ref> beta-Amanitin is also an inhibitor of eukaryotic RNA polymerase II and RNA polymerase III, and as a result, mammalian protein synthesis. It has not been found to inhibit RNA polymerase I or bacterial RNA polymerase.<ref name = "Sigma-Alrich_A1304">{{cite web | url = http://www.sigmaaldrich.com/catalog/product/sigma/a1304?lang=en&region=US | title = β-Amanitin from Amanita phalloides | access-date = 12 March 2013 | work = Sigma-Aldrich }}</ref> Because it inactivates the RNA polymerases, the liver is unable to repair damage and the cells of the liver die off quickly.<ref>{{cite web | url = https://www.ansci.cornell.edu/plants/toxicagents/polypeptides.html | title = Polypeptide Toxins in Amanita Mushrooms | publisher = Cornell University | access-date = 12 March 2013 }}</ref>

[[Image:Alpha-Amanitin–RNA polymerase II complex 1K83.png|thumb|alt=Ribbon diagram of RNA polymerase II molecule showing central binding site of alpha-amanitin molecule|α-Amanitin (red) bound to RNA polymerase II from ''Saccharomyces cerevisiae'' (brewer's yeast). From {{PDB|1K83}}.<ref name="Bushnell_2002">{{cite journal | vauthors = Bushnell DA, Cramer P, Kornberg RD | title = Structural basis of transcription: alpha-amanitin-RNA polymerase II cocrystal at 2.8 A resolution | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 99 | issue = 3 | pages = 1218–1222 | date = February 2002 | pmid = 11805306 | pmc = 122170 | doi = 10.1073/pnas.251664698 | doi-access = free | bibcode = 2002PNAS...99.1218B }}</ref>]]

Alpha-amanitin (α-Amanitin) primarily affects the bridge helix of the RNA pol II complex, a highly conserved domain 35 amino acids long. At the N-terminus and the C-terminus of this region there are hinge structures that undergo significant conformational changes throughout the nucleotide addition cycle, and are essential for its progression.<ref>{{cite journal | vauthors = Weinzierl RO | title = The Bridge Helix of RNA polymerase acts as a central nanomechanical switchboard for coordinating catalysis and substrate movement | journal = Archaea | volume = 2011 | article-number = 608385 | date = Sep 2011 | pmid = 22312317 | pmc = 3270539 | doi = 10.1155/2011/608385 | doi-access = free }}</ref> One of the many roles of the bridge helix is facilitating the translocation of DNA.<ref>{{cite journal | vauthors = Hein PP, Landick R | title = The bridge helix coordinates movements of modules in RNA polymerase | journal = BMC Biology | volume = 8 | article-number = 141 | date = November 2010 | pmid = 21114873 | pmc = 2993669 | doi = 10.1186/1741-7007-8-141 | doi-access = free }}</ref> Alpha-amanitin binds to the bridge helix of the RNA Pol II complex and it also binds to part of the complex that is adjacent to the bridge helix, while it is in one specific conformation. This binding locks the bridge helix into place, dramatically slowing its movement in translocating the DNA.<ref name="Bushnell_2002"/> The rate of pol II translocation of DNA is reduced from several thousand to a few nucleotides per minute.<ref>{{cite journal | vauthors = Chafin DR, Guo H, Price DH | title = Action of alpha-amanitin during pyrophosphorolysis and elongation by RNA polymerase II | journal = The Journal of Biological Chemistry | volume = 270 | issue = 32 | pages = 19114–19119 | date = August 1995 | pmid = 7642577 | doi = 10.1074/jbc.270.32.19114 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Rudd MD, Luse DS | title = Amanitin greatly reduces the rate of transcription by RNA polymerase II ternary complexes but fails to inhibit some transcript cleavage modes | journal = The Journal of Biological Chemistry | volume = 271 | issue = 35 | pages = 21549–21558 | date = August 1996 | pmid = 8702941 | doi = 10.1074/jbc.271.35.21549 | doi-access = free }}</ref>

==Symptoms of exposure== Upon exposure to amatoxins, the liver is the principal organ affected as it is the organ which is first encountered after absorption in the gastrointestinal tract. There is no evidence that amatoxins are absorbed through skin. One study done on mice shows that alpha-Amanitin is not absorbed through skin and therefore cannot have any toxic effects.<ref name="pmid23763309">{{cite journal | vauthors = Kaya E, Surmen MG, Yaykasli KO, Karahan S, Oktay M, Turan H, Colakoglu S, Erdem H | display-authors = 6 | title = Dermal absorption and toxicity of alpha amanitin in mice | journal = Cutaneous and Ocular Toxicology | volume = 33 | issue = 2 | pages = 154–160 | date = June 2014 | pmid = 23763309 | doi = 10.3109/15569527.2013.802697 | s2cid = 32405244 | hdl = 20.500.12684/5479 | hdl-access = free }}</ref> More specifically, exposure to amatoxins may cause irritation of the respiratory tract, headache, dizziness, nausea, shortness of breath, coughing, insomnia, diarrhea, gastrointestinal disturbances, back pain, urinary frequency, liver and kidney damage, or death if ingested or inhaled. For β-amanitin, there has been no full toxicological study. However, safety data sheets indicate that if it comes in contact with skin, it may cause irritation, burns, redness, severe pain, and could be absorbed through the skin, causing similar effects to exposure via inhalation and ingestion. Contact with the eyes may result in irritation, corneal burns, and eye damage.<ref name = "Sigma-Alrich_MSDS">{{cite web | title = β-Amanitin from Amanita phalloides |work = Safety Data Sheet | publisher = Sigma-Aldrich | id = Catalog number A1304 |url= https://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=A1304&brand=SIGMA&PageToGoToURL=https://www.sigmaaldrich.com/catalog/product/sigma/a1304?lang=en|access-date=2021-05-11 }}</ref> Persons with pre-existing skin, eye, or central nervous systems disorders, impaired liver, kidney, or pulmonary function may be more susceptible to the effects of this substance.

The estimated minimum lethal dose is 0.1 mg/kg or 7  to 10 milligrams of toxin in adults. Their swift intestinal absorption coupled with their thermostability leads to rapid development of toxic effects in a relatively short period of time. The most severe effects are toxic hepatitis with centrolobular necrosis and hepatic steatosis, as well as acute tubulointerstitial nephropathy, which altogether induce severe liver failure and kidney failure.

==Treatment== There are many anecdotal and partially-studied treatments in use worldwide. One study in mice showed null results for all studied treatments. Treatments showing no discernable value included N-acetylcysteine, benzylpenicillin, cimetidine, thioctic acid, and silybin.<ref>{{cite journal | vauthors = Tong TC, Hernandez M, Richardson WH, Betten DP, Favata M, Riffenburgh RH, Clark RF, Tanen DA | display-authors = 6 | title = Comparative treatment of alpha-amanitin poisoning with N-acetylcysteine, benzylpenicillin, cimetidine, thioctic acid, and silybin in a murine model | journal = Annals of Emergency Medicine | volume = 50 | issue = 3 | pages = 282–288 | date = September 2007 | pmid = 17559970 | doi = 10.1016/j.annemergmed.2006.12.015 }}</ref>

Treatment involves high-dose penicillin as well as supportive care in cases of hepatic and renal injury. Silibinin, a product found in milk thistle, is a potential antidote to amatoxin poisoning, although more data needs to be collected. Cautious attention is given to maintaining hemodynamic stability, although if hepatorenal syndrome has developed the prognosis is guarded at best.<ref>{{cite journal | vauthors = Piqueras J | title = Hepatotoxic mushroom poisoning: diagnosis and management | journal = Mycopathologia | volume = 105 | issue = 2 | pages = 99–110 | date = February 1989 | pmid = 2664527 | doi = 10.1007/bf00444032 | s2cid = 29687288 }}</ref>

==Detection== Presence of amatoxins in mushroom samples may be detected by the Meixner test (also known as the Wieland test). The amatoxins may be quantitated in plasma or urine using chromatographic techniques to confirm a diagnosis of poisoning in hospitalized patients and in postmortem tissues to aid in a medicolegal investigation of a suspected fatal overdosage.<ref>{{cite book | vauthors = Baselt R | title = Disposition of Toxic Drugs and Chemicals in Man | edition = 8th | publisher = Biomedical Publications | location = Foster City, CA | date = 2008 | pages = 52–54 }}</ref>

In 2020, a monoclonal antibody-based lateral flow immunoassay has been developed that can quickly and selectively detect amatoxins.<ref>{{cite journal | vauthors = Bever CS, Adams CA, Hnasko RM, Cheng LW, Stanker LH | title = Lateral flow immunoassay (LFIA) for the detection of lethal amatoxins from mushrooms | journal = PLOS ONE | volume = 15 | issue = 4 | article-number = e0231781 | date = 2020-04-17 | pmid = 32302363 | pmc = 7164595 | doi = 10.1371/journal.pone.0231781 | doi-access = free | bibcode = 2020PLoSO..1531781B }}</ref><ref>{{cite journal | vauthors = Bever CS, Swanson KD, Hamelin EI, Filigenzi M, Poppenga RH, Kaae J, Cheng LW, Stanker LH | display-authors = 6 | title = Rapid, Sensitive, and Accurate Point-of-Care Detection of Lethal Amatoxins in Urine | journal = Toxins | volume = 12 | issue = 2 | page = 123 | date = February 2020 | pmid = 32075251 | pmc = 7076753 | doi = 10.3390/toxins12020123 | doi-access = free }}</ref> This test sensitively detects alpha-amanitin and gamma-amanitin (clearly detects 10 ng/mL), and exhibits slightly less detection for beta-amanitin (0.5% cross-reactivity; 2000 ng/mL). Although this test cross-reacts with phallotoxins at 0.005% (200,000 ng/mL), the phallotoxins would not interfere in urine sampling and there are very rare instances where a mushroom produces phallotoxins without producing amatoxins.

== Studies ==

In a 2013 study on the toxin concentration in ''Amanita phalloides'', all parts of the mushroom were found to contain amatoxins and it was determined that the highest concentrations were found in the gills and cap with the lowest levels in the spores and mycelium.<ref name="Kaya_2015">{{cite journal | vauthors = Kaya E, Karahan S, Bayram R, Yaykasli KO, Colakoglu S, Saritas A | title = Amatoxin and phallotoxin concentration in Amanita phalloides spores and tissues | journal = Toxicology and Industrial Health | volume = 31 | issue = 12 | pages = 1172–1177 | date = December 2015 | pmid = 23719849 | doi = 10.1177/0748233713491809 | bibcode = 2015ToxIH..31.1172K | s2cid = 206543780 | hdl = 20.500.12684/2600 | hdl-access = free }}</ref> An additional study published in 2013 by many of the same authors found no difference in the ITS sequence of ''Amanita phalloides var. alba'' but did find different concentrations of toxins.<ref name="Kaya_2013">{{cite journal | vauthors = Kaya E, Yilmaz I, Sinirlioglu ZA, Karahan S, Bayram R, Yaykasli KO, Colakoglu S, Saritas A, Severoglu Z | display-authors = 6 | title = Amanitin and phallotoxin concentration in Amanita phalloides var. alba mushroom | journal = Toxicon | volume = 76 | pages = 225–233 | date = December 2013 | pmid = 24139877 | doi = 10.1016/j.toxicon.2013.10.008 | bibcode = 2013Txcn...76..225K | hdl = 20.500.12684/2599 | hdl-access = free }}</ref> The gills and cap of ''Amanita phalloides var. alba'' also contained the highest level with very low levels noted in the spores, volva and stipe however in this variant the spores had a higher concentration of all toxins besides gamma amanitin than was found in ''Amanita phalloides.'' The spores of ''Amanita phalloides var. alba'' contained 0.89 mg/g of alpha-amanitin, 0.48 mg/g of beta-amanitin and 0.001 mg/g gamma-amanitin in contrast to the 2.46, 1.94 and 0.36 mg/g found in the gills and the 2.40, 1.75 and 0.27 mg/g found in the cap. The concentration found in the gills, cap, stipe and volva of ''Amanita phalloides var. alba'' is lower than in ''Amanita phalloides'' however the spores were shown to contain a higher concentration.<ref name="Kaya_2013" /> In both studies six mushrooms were spore printed, dried and tested with the toxin level in the whole mushroom being derived from testing one half of the whole mushroom cut down the middle, the other half was divided into cap, gill, stipe and volva sections to test individually with the parts ground into a powder and tested as 1gram samples.<ref name="Kaya_2015" /><ref name="Kaya_2013" /> In 2010, a study on ''Amanita bisporigera'', the destroying angel, determined that the concentrations of toxins in the spores were also lower than the levels found in the cap or stipe.<ref name="Mcknight_2010">{{cite journal | vauthors = Mcknight TA, Mcknight KB, Skeels MC | title = Amatoxin and phallotoxin concentration in amanita bisporigera spores | journal = Mycologia | volume = 102 | issue = 4 | pages = 763–765 | date = 2010 | pmid = 20648744 | doi = 10.3852/09-131 | s2cid = 29289507 }}</ref> {| class="wikitable" |+ Toxin concentration in ''Amanita phalloides'' (mg/g)<ref name="Kaya_2015" /> !Toxin !Cap !Gills !Stipe !Volva !Spores !Whole dry mushroom !Whole fresh mushroom !Mycelium |- |Alpha-amanitin |2.95 |3.39 |2.36 |1.03 |0.087 |2.80 |0.33 |0.024 |- |Beta-amanitin |2.53 |2.95 |1.75 |0.64 |0.048 |2.38 |0.28 |0.01 |- |Gamma-amanitin |0.62 |0.66 |0.5 |0.25 |0.18 |0.6 |0.07 |0.24 |- |Phallacidin |2.27 |2.06 |2.04 |1.88 |0.055 |2.12 |0.25 |0.42 |- |Phalloidin |1.40 |1.38 |1.18 |1.25 |0.018 |1.32 |0.15 |0.01 |}

{| class="wikitable" |+ Toxin concentration in ''Amanita phalloides var. alba'' (mg/g)<ref name="Kaya_2013" /> !Toxin !Cap !Gills !Stipe !Volva !Spores !Whole dry mushroom !Whole fresh mushroom |- |Alpha-amanitin |2.40 |2.46 |1.52 |0.56 |0.89 |2.14 |0.21 |- |Beta-amanitin |1.75 |1.94 |1.00 |0.36 |0.48 |1.71 |0.16 |- |Gamma-amanitin |0.27 |0.36 |0.21 |0.07 |0.001 |0.31 |0.03 |- |Phallacidin |1.64 |2.26 |2.06 |2.08 |0.99 |2.10 |0.20 |- |Phalloidin |0.87 |1.30 |1.13 |1.34 |0.12 |1.09 |0.10 |}

{| class="wikitable" |+ Toxin concentration in ''Amanita bisporigera'' (mg/g)<ref name="Mcknight_2010" /> !Toxin !Cap !Stipe !Spores |- |Alpha-amanitin |1.70 ± 0.68 |1.70 ± 0.45 |0.30 ± 0.04 |- |Phallacidin |2.71 ± 0.65 |1.66 ± 0.40 |0.02 ± 0.01 |- |Phalloidin |11.98 ± 1.66 |11.15 ± 2.43 |0.00 ± 0.05 |}

Amatoxins are extremely toxic to humans with ''Amanita phalloides'' and its variants making up many of the cases of fatal toxicity after consumption.These toxins have high heat stability and this property combined with their solubility in water make them exceptionally toxic as they are not destroyed by cooking or drying.<ref name="Garcia_2015">{{cite journal | vauthors = Garcia J, Costa VM, Carvalho A, Baptista P, de Pinho PG, de Lourdes Bastos M, Carvalho F | title = Amanita phalloides poisoning: Mechanisms of toxicity and treatment | journal = Food and Chemical Toxicology | volume = 86 | pages = 41–55 | date = December 2015 | pmid = 26375431 | doi = 10.1016/j.fct.2015.09.008 | hdl = 10198/17717 | hdl-access = free }}</ref> In addition, amatoxins are resistant to enzyme and acid degradation, and therefore when ingested they are not inactivated in the gastrointestinal tract.<ref name="Garcia_2015" /> A fatal case was reported after consuming ''A. phalloides'' that had been frozen for 7–8 months, thus demonstrating that these compounds are also resistant to the freeze/thawing processes.<ref name="Garcia_2015" /> Additionally, amatoxins decompose very slowly when stored in open, aqueous solutions or following prolonged exposure to sun or neon light.<ref name="Garcia_2015" />

In 2015, a case study was conducted on a patient who cooked and consumed just the caps from two ''Amanita phalloides'' mushrooms and was subsequently admitted to hospital a day later. The subject was a 61-year-old man with a body weight of 67 kg who was presenting with fatigue, abdominal pain, nausea, vomiting and diarrhea. Mushrooms were collected from the same region and shown to the patient in order to confirm that these were what he had eaten and two mushrooms of approximately the same size and level of maturity were selected for study.<ref name="Yilmaz_2015">{{cite journal | vauthors = Yilmaz I, Ermis F, Akata I, Kaya E | title = A Case Study: What Doses of Amanita phalloides and Amatoxins Are Lethal to Humans? | journal = Wilderness & Environmental Medicine | volume = 26 | issue = 4 | pages = 491–496 | date = December 2015 | pmid = 26453489 | doi = 10.1016/j.wem.2015.08.002 | doi-access = free | hdl = 20.500.12684/2308 | hdl-access = free }}</ref> Previous studies have demonstrated that younger mushrooms can contain a higher concentration of toxins than is found in mature specimens.<ref>{{cite journal | vauthors = Vetter J | title = Toxins of Amanita phalloides | journal = Toxicon | volume = 36 | issue = 1 | pages = 13–24 | date = January 1998 | pmid = 9604278 | doi = 10.1016/S0041-0101(97)00074-3 | bibcode = 1998Txcn...36...13V }}</ref> The combined weight of the caps of these two mushrooms was 43.4g fresh or 4.3g when dry and when tested were found to contain a total of 21.3 mg of amatoxin distributed as 11.9 mg alpha-amanitin, 8.4 mg beta-amanitin and 1 mg gamma-amanitin. Analysis of the patient's urine after 4 days of treatment in hospital showed a concentration of 2.7 ng/ml alpha-amanitin and 1.25 ng/ml beta-amanitin with no gamma-amanitin detected. The patient survived and was discharged after 9 days of treatment with follow up tests showing no signs of liver damage but based on this case it was estimated that an oral dose of 0.32 mg amatoxin per kg of body mass could be lethal with an approximate lethal dose of alpha-amanitin being 0.2 mg/kg when taken orally. It was estimated that consuming more than 50g of fresh ''Amanita phalloides'', roughly 2 medium-sized mushrooms could be deadly. Clinical tests showed that the amount consumed by the patient remained below the hypothetical lethal dose, which the study notes probably varies depending on patient health, predisposition to liver damage and regional variation in toxin concentrations.<ref name="Yilmaz_2015" />

Anecdotes have been repeated in field guides that claim foragers have fallen ill from spores alone after collecting toxic ''Amanita'' species in the same basket, unwittingly leaving their spores to collect on the harvest before the toxic ones were discarded. This subject however has not been researched and studies make no claims one way or the other as to the possibility of poisoning from spores alone. Given that the concentration of toxins found in the spores is lower than that of the cap, it would require the consumption of a substantial mass of spores, in excess of the weight of the mushroom caps themselves, in order to reach a fatal dose.

== Mushroom species == Amatoxin-containing mushroom species from the genera ''Amanita'', ''Galerina'' and ''Lepiota''.<ref>{{cite journal | vauthors = Enjalbert F, Rapior S, Nouguier-Soulé J, Guillon S, Amouroux N, Cabot C | title = Treatment of amatoxin poisoning: 20-year retrospective analysis | journal = Journal of Toxicology. Clinical Toxicology | volume = 40 | issue = 6 | pages = 715–757 | date = 26 November 2002 | pmid = 12475187 | doi = 10.1081/CLT-120014646 | s2cid = 22919515 }}</ref><ref>{{cite book| vauthors = Walton J |title=The cyclic peptide toxins of Amanita and other poisonous mushrooms| date = 9 May 2018 |isbn=978-3-319-76822-9|location=Cham, Switzerland | publisher = Springer |oclc=1035556400}}</ref> {| class="wikitable" |- ! ''Amanita'' species !! ''Galerina'' species !! ''Lepiota'' species |- | ''Amanita phalloides'' || ''Galerina badipes'' || ''Lepiota brunneoincarnata'' |- | ''Amanita bisporigera'' || ''Galerina beinrothii'' || ''Lepiota brunneolilacea'' |- | ''Amanita decipiens'' || ''Galerina fasciculata'' || ''Lepiota castanea'' |- | ''Amanita hygroscopica'' || ''Galerina helvoliceps'' || ''Lepiota clypeolaria'' |- | ''Amanita ocreata'' || ''Galerina marginata'' || ''Lepiota clypeolarioides'' |- | ''Amanita suballiacea'' || ''Galerina sulciceps'' || ''Lepiota felina'' |- | ''Amanita tenuifolia'' || ''Galerina unicolor'' || ''Lepiota fulvella'' |- | ''Amanita verna'' || ''Galerina venenata'' || ''Lepiota fuscovinacea'' |- | ''Amanita virosa'' || || ''Lepiota griseovirens'' |- | || || ''Lepiota heimii'' |- | || || ''Lepiota helveoloides'' |- | || || ''Lepiota kuehneri'' |- | || || ''Lepiota langei'' |- | || || ''Lepiota lilacea'' |- | || || ''Lepiota locanensis'' |- | || || ''Lepiota ochraceofulva'' |- | || || ''Lepiota pseudohelveola'' |- | || || ''Lepiota pseudolilacea'' |- | || || ''Lepiota rufescens'' |- | || || ''Lepiota subincarnata'' |- | || || ''Lepiota xanthophylla'' |}

== See also == * Phallotoxins, a closely related class of mycotoxins

== References == {{reflist|30em}}

Category:Amatoxins Category:Hepatotoxins Category:RNA polymerase inhibitors Category:Cyclic peptides