Amanita ocreata

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Amanita ocreata
Western North American destroying angel

Least Concern  (IUCN 3.1)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Amanitaceae
Genus: Amanita
Species:
A. ocreata
Binomial name
Amanita ocreata
Approximate distribution (green)
Amanita ocreata
View the Mycomorphbox template that generates the following list
Gills on hymenium
Cap is convex or flat
mycorrhizal
Edibility is deadly

Amanita ocreata, commonly known as the death angel, destroying angel, angel of death or more precisely western North American destroying angel, is a deadly

A. lanei or Volvopluteus gloiocephalus, while immature specimens may be difficult to distinguish from edible Agaricus
mushrooms or puffballs.

The species occurs in the

gastrointestinal and include abdominal pain, diarrhea and vomiting. These subside temporarily after 2–3 days, though ongoing damage to internal organs during this time is common; symptoms of jaundice, diarrhea, delirium, seizures, and coma
may follow with death from liver failure 6–16 days post ingestion.

Taxonomy

Amanita ocreata was first described by American

specific epithet is derived from the Latin ocrěātus 'wearing greaves' from ocrea 'greave',[6] referring to its loose, baggy volva.[7] Amanita bivolvata is a botanical synonym. The mushroom belongs to the same section (Phalloideae) and genus (Amanita) as several deadly poisonous fungi including the death cap (A. phalloides) and several all-white species of Amanita known as "destroying angels": A. bisporigera of eastern North America, and the European A. virosa
. "Death angel" is used as an alternate common name.

Description

Amanita ocreata is generally stouter than the other fungi termed destroying angels. It first appears as a white egg-shaped object covered with a universal

μm viewed under a microscope.[3] There is typically no smell, though some fruiting bodies may have a slight odour, described as that of bleach or chlorine, dead fish or iodine. Like other destroying angels, the flesh stains yellow when treated with potassium hydroxide.[9][10]

Similar species

This fungus resembles the edible mushrooms

Volvariella speciosa has pink spores and no ring or volva.[11]

Distribution and habitat

Appearing from January to April, A. ocreata occurs later in the year than other amanitas except A. calyptroderma. It is found in mixed woodland on the

Garry oak (Quercus garryana).[12]

Toxicity

A. ocreata is highly toxic, and has been responsible for mushroom poisonings in western North America, particularly in the spring. It contains highly toxic amatoxins, as well as phallotoxins, a feature shared with the closely related death cap (A. phalloides), half a cap of which can be enough to kill a human, and other species known as destroying angels.[3][14] There is some evidence it may be the most toxic of all the North American phalloideae, as a higher proportion of people consuming it had organ damage and 40% perished.[15] Dogs have also been known to consume this fungus in California with fatal results.[16]

Amatoxins consist of at least eight compounds with a similar structure, that of eight amino-acid rings;[17] of those found in A. ocreata, α-Amanitin is the most prevalent and along with β-Amanitin is likely to be responsible for the toxic effects.[3][18][19] The major toxic mechanism is the inhibition of RNA polymerase II, a vital enzyme in the synthesis of messenger RNA (mRNA), microRNA, and small nuclear RNA (snRNA). Without mRNA, essential protein synthesis and hence cell metabolism stop and the cell dies.[20] The liver is the principal organ affected, as it is the first organ encountered after absorption by the gastrointestinal tract, though other organs, especially the kidneys, are susceptible to the toxins.[21]

The phallotoxins consist of at least seven compounds, all of which have seven similar peptide rings. Although they are highly toxic to liver cells,[22] phallotoxins have since been found to have little input into the destroying angel's toxicity as they are not absorbed through the gut.[20] Furthermore, one phallotoxin, phalloidin, is also found in the edible (and sought-after) blusher (Amanita rubescens).[17]

Signs and symptoms

Signs and symptoms of poisoning by A. ocreata are initially

hemorrhage, sepsis, pancreatitis, acute kidney injury, and cardiac arrest.[23][24] Death generally occurs six to sixteen days after the poisoning.[28]

Treatment

Consumption of A. ocreata is a medical emergency that requires hospitalization. There are four main categories of therapy for poisoning: preliminary medical care, supportive measures, specific treatments, and liver transplantation.[4]

Preliminary care consists of gastric decontamination with either activated carbon or gastric lavage. However, due to the delay between ingestion and the first symptoms of poisoning, it is commonplace for patients to arrive for treatment long after ingestion, potentially reducing the efficacy of these interventions.[4][29] Supportive measures are directed towards treating the dehydration which results from fluid loss during the gastrointestinal phase of intoxication and correction of metabolic acidosis, hypoglycemia, electrolyte imbalances, and impaired coagulation.[4]

No definitive antidote for amatoxin poisoning is available, but some specific treatments such as intravenous

sequelae if treated within 36 hours of the mushrooms ingestion.[35]

See also

References

  1. doi:10.2305/IUCN.UK.2021-2.RLTS.T198477478A198489125.en
    . Retrieved 25 September 2021.
  2. ISBN 9780898153880
    .
  3. ^
    PMID 564452
    .
  4. ^
    S2CID 22919515
    .
  5. JSTOR 2479371
    .
  6. ISBN 978-0-304-52257-6
    .
  7. ^
    ISBN 978-0-89815-169-5
    .
  8. ^
    OCLC 797915861
    .
  9. ISBN 0-916422-24-0
    .
  10. ^ a b c Tulloss, Rodham E. "Amanita ocreata Peck "Western American Destroying Angel"". Studies in the Amanitaceae. Retrieved 2011-02-11.
  11. ^ Wood, Michael; Fred Stevens (1998–2007). "California fungi:Amanita ocreata". The Fungi of California. Archived from the original on 11 October 2007. Retrieved 2007-11-13.
  12. ^ a b Birch, Shannon (April 2006). "Is Amanita ocreata on Vancouver Island?" (PDF). Fungifama: 5. Retrieved 2007-12-11.
  13. ^ Benjamin, Mushrooms: poisons and panaceas, p. 205
  14. ^ Benjamin, Mushrooms: poisons and panaceas p. 211
  15. ^ Beug, Michael (April 2006). "Reflections on Mushroom Poisoning – Part I" (PDF). Fungifama: 3–5. Retrieved 2007-12-11.
  16. PMID 11931514
    .
  17. ^
    PMID 1114308
    .
  18. PMID 8146866
    .
  19. ISBN 978-0-7817-2845-4
    .
  20. ^
    PMID 14505933
    .
  21. ^ Benjamin, Mushrooms: poisons and panaceas, p. 217
  22. S2CID 39255487
    .
  23. ^
    PMID 2334013
    .
  24. ^
    PMID 2643869
    .
  25. OCLC 955264
    .
  26. PMID 7603660
    .
  27. PMID 9604278
    .
  28. PMID 8656182
    .
  29. S2CID 23016936
    .
  30. PMID 6291147
    .
  31. S2CID 19805371
    .
  32. PMID 8937042
    .
  33. PMID 15664245
    .
  34. ^ Benjamin, Mushrooms: poisons and panaceas, pp. 231–232
  35. S2CID 37788880
    .

Works cited

External links

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