Mushrooms, poisonous

In Europe Amanita species, particularly Amanita phalloides and to a lesser extent A. virosa, are responsible for about 75% of fatal fungal poisonings. Most of these arise as a consequence of mis-identifications. 

The toxicity of Amanita species is due to the presence of a family of bicyclic octapeptides known as the amanitins (9.26). The phallotoxins, which are also 

phalloides cap is about 30-60mg. Amatoxin poisoning follows three stages, an initial period of severe gastrointestinal disturbance about 8-36 hours after ingestion, a period of apparent recovery followed by a terminal phase approximately 3-4 days after ingestion in which liver and kidney failure occur, leading to death. 

Psilocybin (4-phosphoryloxy-iV,A -dimethyltryptamine) (9.31) and the parent alcohol, psilocin, were first isolated from the Mexican mushroom Psilocybe mexicana by Hofmann in 1959. Since then these hallucinogenic metabolites have been reported in more than 30 species of this genus and its relatives. The highest concentration (over 0.5% dry weight) of psilocybin has been detected in Conocybe cyanopus and Psilocybe semilanceata. The hallucinogenic properties of these organisms have led to their colloquial name as magic mushrooms . P. semilanceata, which is quite widespread in Europe, is sometimes known as the Liberty Cap. A biosynthetic sequence from tryptophan to psilocybin has been established. 

When the ink-cap mushroom Coprinus atramentarius is eaten alone it is not toxic. However, if it is eaten with alcohol it induces an over-sensitivity that is similar to that of the drug disulphiram (antabuse). The fresh mushroom contains about 160 mg kg of the active component, coprine (9.34). This was shown to be A -(l-hydroxycyclopropyl)-L-glutamine, which contains the unusual Wacyl-l-aminocyclopropanol unit. It is metabolized to L-glutamic acid and cyclopropanone. The hydrate of cyclopropanone is a good inhibitor of acetaldehyde dehydrogenase. This induces elevated levels of acetaldehyde in the blood and retards the rate of ethanol metabolism. 

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The betalains are confined to ten families of the order Caryophyllales20 The only foods containing betalains are red beet (Beta vulgaris), chard (B. vulgaris), cactus fruit (Opuntia ficus-indica) and pokeberries (Phytolacca americana). They also occur in the poisonous mushroom Amanita muscaria but this is not a normal food source. The importance of the betalains as colorants is confined to preparations from red beet. 

Fukawatari, T., Suigimoto, E. and Shibata, K. (2001). Effect of feeding with a poisonous mushroom Clitocybe acromelalga on the metabolism of tryptophan-niacin in rats. Shokuhin Eiseigaku Zasshi, 42, 190-196. 

Stijve, T. (1981). High performance thin-layer chromatographic determination of the toxic principles of some poisonous mushrooms, Mitt. Geb. Lebensmittelunters. Hyg., 72, 2432-2436. 

Note that it shares some structural features with the acetylcholine molecule. Specifically, both molecules possess an oxygen atom separated by two methylene (-CH2-) groups from a positively charged nitrogen atom. Muscarine was isolated from Amanita muscaria, a poisonous mushroom, more than a century ago. Muscarine causes sweating and pupillary constriction. These are some of the same effects that are caused by acetylcholine itself, confirming that muscarine is an acetylcholine agonist. 

The production and sale of coffee is a large international business solely designed to satisfy the demand for caffeine, the most widely consumed stimulant in the world. Mushrooms present another interesting challenge. Every year people are sickened and even die from eating poison mushrooms, while others consume them for their hallucinogenic effects. 

Each year, more than 100 people worldwide die after eating poisonous mushrooms. 

Muscaflavin, a yellow pigment from the poisonous mushroom Amanita muscaria has the unusual dihydroazepine-amino acid structure (288) (81LA2164). 

Amanitin. Toxin from poisonous mushroom Aminita phalloides... 

The most useful inhibitor of eukaryotic transcription has been a-amanitin, a major toxic substance in the poisonous mushroom Amanita phalloides. The toxin preferentially binds to and inhibits RNA polymerase II (see table 28.4). At high concentrations it also can inhibit RNA polymerase III but not RNA polymerase I or bacterial, mitochondrial, or chloroplast RNA polymerases. 

Cholinergic receptors are subdivided into two categories nicotinic and muscarinic. Although acetylcholine will bind to all cholinergic receptors, certain receptors bind preferentially with the drug nicotine. Other receptors have a specific affinity for muscarine, a naturally occurring compound found in certain poisonous mushrooms. Thus the terms nicotinic and muscarinic were derived. 

Some Psilocybe mushroom eaters, in an effort to avoid LSD and PCP tainted varieties sold on the street, try to pick their own mushrooms. In theory, this should be easy to do. Psilocybe (species containing psilocybin) mushrooms grow naturally around the world and in the United States particularly in the Pacific Northwest and southeastern states. Mushroom hunters often seek out cow pastures, riverbanks, pine forests, and wood chips in search of over 90 known species of Psilocybe mushrooms. The problem, though, is that it is very difficult to tell the difference between Psilocybe and other poisonous mushrooms. Psilocybe and poisonous look-alikes can grow side by side. 

Mushrooms are spore-forming bodies of filamentous terrestrial fungi, some of which are considered to be food delicacies, whereas others, such as Amanita phalloides, Amanita virosa, and Gyromita esculenta, are very toxic, with reported worldwide deaths of the order of 100 per year.10 In extreme cases, one bite of one poisonous mushroom can be fatal. Accidental mushroom poisonings are often caused by the death s head mushroom, because it is easily mistaken for edible varieties. 

Eukaryotic cells contain at least four different DNA-dependent RNA polymerases. Their localization, cellular transcripts, and susceptibility to the cyclic octapeptide a-amanitin (derived from poisonous mushrooms) are shown in Table 11.3. a-Amanitin blocks the elongation phase of RNA synthesis. Although the structures of these enzymes are much more complex than that of the prokaryotic RNA polymerase, the basic mechanism is very similar to that of the prokaryotic enzyme. 

Mouton and Company, The Hague/Paris Gary Menser, Hallucinogenic and Poisonous Mushroom Field Guide Richard Evans Schultes, Professor of Natural Sciences Director Botanical Museum, Flarvard University, Oxford St., Cambridge, Mass. 02138 R.E.L. Masters and Jean Houston, The Varieties of Psychedelic Experience. 

The nanacates are poisonous mushrooms which have nothing to do with peyote. It is known from olden times that their use induces intoxication, states of ecstasy and mental aberrations, but, notwithstanding the dangers attendant upon their use, people everywhere they grow have taken advantage of their intoxicating properties up to the present time. 

J.Q. Jacobs Hallucinogenic and Poisonous Mushroom Field Guide... 

Amanita phalloides, an extremely poisonous mushroom, popularly known as "Death Cap. ... 

These receptors, in addition to binding acetylcholine, also recognize muscarine, an alkaloid that is present in certain poisonous mushrooms. By contrast, the muscarinic receptors show only a weak affinity for nicotine (Figure 4.4). Using binding studies and specific inhibitors, several subclasses of muscarinic receptors have been pharmacologically distinguished as Mi, M2, M3, M4, and M5. 

Trehalose is a nonreducing disaccharide (C12H22O11) isolated from the poisonous mushroom Amanita muscaria. Treatment with an a-glucosidase converts trehalose to two molecules of glucose, but no reaction occurs when trehalose is treated with a j3-glucosidase. When trehalose is methylated by dimethyl sulfate in mild base and then hydrolyzed, the only product is 2,3,4,6-tetra-O-methylglucose. Propose a complete structure and systematic name for trehalose. 

Examine Figure 4.5. Which mushroom looks more appetizing to you An expert will always be able to distinguish an edible mushroom from a poisonous mushroom based on the characteristics that have been used to classify each type. By classifying, they can predict the effects of eating any wild mushroom. 

Figure 28.16. RNA Polymerase Poison. Amanita phalloides, a poisonous mushroom that produces a-amanitin. [After G. Lincoff and D. H. Mitchel, Toxic and Hallucinogenic Mushroom Poisoning (Van Nostrand Reinhold, 1977), p. 30.]...

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