but deadly - a look at some of the more
by Jan Parmentier, the Netherlands
Editor's note: this article was written to complement M. Halit Umar's article 'I love fungi'.
There is no safe and simple method to distinguish a toxic from an edible mushroom. The only and tiresome way is to learn the species in the field, helped by an expert and good books. However, it is possible to learn very quickly when extreme care is necessary. When a mushroom or toadstool has white gills, a ring and a bulbous volva at the base of the stem, it belongs to the genus Amanita, and in that genus you will find the really deadly poisonous species. In Europe, Amanita phalloides, the Death Cap, is responsible for probably more than 90% of the fatal mushroom poisonings.
The Death Cap is a beautiful mushroom, looking very tasty, but one specimen is more than sufficient for a painful death. The onset of the symptoms is delayed, gastrointestinal symptoms occur usually after 8-12 hours. The terminal phase is after 72-96 hours. The main poisons of the Death Cap are phallotoxins and amanitins. These compounds are all bicyclic peptides; amanitins are octapeptides, phallotoxins are heptapeptides, so the latter have one less amino acid. Alpha-amanitin is extraordinarily toxic for humans. 5-10 milligrams can kill the average person and the average cap of Amanita phalloides contains 30-90 milligrams. The poison inhibits the workings of RNA polymerase with the consequence of inhibiting all protein synthesis. Cell death ensues. Because the liver is responsible for a major portion of protein synthesis in the body, the failure of the liver is the most prominent feature of a poisoning by the Death Cap. The genus Amanita contains some of the most beautiful mushrooms we know.
The photographs show the Death Cap (Amanita phalloides) above, and the Panther Cap (Amanita pantherina) and the Fly Agaric (Amanita muscaria) below. The folk names of several Amanita's indicate already their dangers, for instance Destroying Angel for A. bisporigera and Fools mushroom for A. verna. Apart from Amanita's, there are other deadly poisonous mushrooms that are not so easy to recognize. So be careful!
Related Micscape articles:
A closer look at mushrooms - a beautifully illustrated introduction to the larger fungi by Jan Parmentier.
Sea wasps and other nightmares - a fascinating look at some poisonous members of the animal kingdom by Richard Howey.
Published in the June 2000 edition of Micscape Magazine.
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