Amanita mushrooms

Muscarine is a poisonous substance present in the mushroom Amanita muscana Its struc ture IS represented by the constitution shown here... 

Phalloidin and phallacidin are cyclic peptides from the mushroom Amanita phalloides that stabilize F-actin. Phalloidin binds to residues 114-118 of an actin protomere and blocks nucleotide exchange without interfering with nucleotide hydrolysis. It enhances the rate of nucleation as well as that of elongation. It slowly penetrates the cell membrane and is used for immunocytochemical localization of F-actin. 

One peptide toxin from the mushroom Amanita phalhides, a-amanitin, is a specific differential inhibitor of the eukaryotic nuclear DNA-dependent RNA polymerases and as such has proved to be a powerful research tool (Table 37-2). a-Amanitin blocks the translocation of RNA polymerase during transcription. 

High levels of vanadium are found in the mushroom Amanita muscaria and in marine tuni-cates (sea squirts). In the former organism, a siderophore-like ligand that binds vanadium(IV)... 

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. 

The muscarinic ACh receptors (of which there are at least five subtypes) are metabotropic. Their name is derived from the alkaloid muscarine, which is found in the fly agaric mushroom (Amanita muscaria), for example. Like ACh, muscarine is bound at the receptor, but in contrast to ACh (see C), it is not broken down and therefore causes permanent stimulation of muscle. 

Stimulation - excitatory amino acids -headache, confusion, hallucinations Red alga (red tide), Green alga Mushrooms - Amanita family (fly agaric), flat pea [Lathyrus] Kainic acid, domoic acid -concentrated in shellfish, Ibotenic acid, muscarinic acid, (hallucinations) Latthyrism - motor neuron degeneration... 

Ingestion of as little as 3 g of the death cap mushroom Amanita phalloides may constitute a lethal dose for some people. 

Classical studies by Sir Henry Dale demonstrated that the receptors activated by muscarine, an alkaloid isolated from the mushroom Amanita muscaria, are the same receptors activated by ACh released from parasympathetic nerve endings, from which the general notion that muscarinic agonists have parasympathomimetic properties was born. This conclusion is true but incomplete, and we now know that muscarinic receptors have a broader distribution and many functional roles. To understand the actions of cholinomimetic drugs it is essential to recognize that muscarinic receptors (1) mediate the activation of effectors by ACh released from parasympathetic nerve... 

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

The Amanita muscaria mushroom from which muscarine is isolated is also psychoactive. It was believed at first that muscarine was the primary CNS agent. However, more detailed research indicated that muscarine only constituted 0.003% of the fungus. Other species of Inocybe and Clitocybe have more muscarine than muscaria. Other isoxazole components of the muscaria mushroom, such as ibotenic acid and its metabolites, are the main causes of amanita intoxication. This mushroom is believed to have been involved in ancient rituals of the Old World, especially in the Ayrian culture which lived in Siberia around 2000 B.C. This rite worshipped a god called Soma whose presence on earth occurred in the mushroom. Amanita muscaria. Rituals involved brewing a juice with the mushrooms which was consumed by priests. Their urine (isoxazole metabolites) was collected and drunk by others. This ceremony could involve many people and several metabolic rounds until everyone was intoxicated. 

Source mushroom Amanita muscaria (fly agaric) found in north temperate climates in wooded areas especially around birch trees... 

The mushroom Amanita phalloides has evolved a very effective defense mechanism against predators. It produces a-amanitin, which disrupts mRNA formation in animal cells by blocking Pol II and, at higher concentrations, Pol III. Neither Pol I nor bacterial RNA polymerase is sensitive to a-amanitin—nor is the RNA polymerase II of A. phalloides itself ... 

Pattern of serum alanine aminotransferase (ALT) and bilirubin in the plasma, following poisoning with the toxic mushroom Amanita phalloides. 

It may be there to poison predators.614 The vanadium-accumulating species also synthesize several complex, yellow catechol-type chelating agents (somewhat similar to enterobactin Fig. 16-1) which presumably complex V(V) and perhaps also reduce it to V(III).615 Vanadium is also accumulated by other marine organisms and by the mushroom Amanita muscaria. 

L(+)-Muscarine, a cholinergic agonist from the mushroom Amanita muscaria... 

The poisonous components of the most deadly mushroom Amanita phalloides (the Death Cap) are bicyclic heptapeptides which have an additional covalent bond that connects the ( -sulfur atom of an l-cysteine residue with the carbon atom in position 2 of the indole ring of the L-tryptophan. Phalloidin (or phalloidine) is the most abundant member of a whole family of related cyclic heptapeptides called phallotoxins (for a review, see Wieland1 1). These poisonous peptides, therefore, contain a cross-linking moiety consisting of L-tryptophan coupled to L-cysteine, designated tryptathionine (1), alternatively called 5-(trypto-phan-2-yl)cysteine or 2-(L-3-alanylsulfenyl)-L-tryptophan (Scheme 1). 

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. 

Yoshimura H, Takegami K, Doe M, Yamashita T, Shibata K, Wakabayashi K, Soga K, Kamisaka S (1999) a-Amino Acids from a Mushroom, Amanita castanopsidis Hongo, with Growth-Inhibiting Activity. Phytochemistry 52 25... 

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