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Polypeptide Toxins in Amanita Mushrooms:

All of the toxins found in the Amanita spp. mentioned in this poisonous plants list are peptides. The distribution of the peptides varies in the different parts of the mushroom, with the cap being the most deadly part. The amatoxins, phallotoxins, and virotoxins are found in A. bisporigera, A. ocreata, A. phalloides, A. phalloides var. alba, A. suballiacea, A. tenuifolia, A. virosa, and some other mushrooms. The phallolysins are a recently discovered group of toxins as yet only seen in A. phalloides. Ibotenic acid is found in A. cothurnata, A. muscaria var.formosa, A. muscaria var.muscaria, and A. pantherina.

[Amatoxins] [Phallotoxins] [Virotoxins] [Phallolysins] [Ibotenic acid/Muscimol] [More Info. on the toxic Amanita spp.] [Toxic Amnita Mushrooms: symptoms and cures] [References] [Return to list of toxicants]

Amatoxins

There are nine amatoxins:

  • alpha-Amanitin
  • beta-Amanitin
  • gamma-Amanitin
  • epsilon-Aminitin
  • Amanin
  • Amanin amide - only found in A. virosa
  • Amanullin
  • Amanullinic acid
  • Proamanullin

Amatoxins are solely responsible for fatal human poisonings. They are bicyclic octapeptides which are much more potent than any of the other toxins. The amatoxins are taken up by the liver where they begin to cause damage. They are then secreted by the bile into the blood where they are taken up by the liver again, causing a cycle of damage and excretion. In the liver, amatoxins inhibit RNA-polymerase II. The liver is slowly destroyed and is unable to repair itself due to the inactivation of the RNA-polymerase. Thus, the liver slowly dissolves with no hope of repair.

Phallotoxins

There are seven naturally occurring phallotoxins:

  • Phalloin
  • Phalloidin
  • Phallisin
  • Prophalloin
  • Phallacin
  • Phallacidin
  • Phallisacin

The phallotoxins are all derived from the same seven amino acid cyclic peptide backbone. There are two groups of phallotoxins, neutral and acidic. The neutral phallotoxins contain D-threonine, while the acidic ones contain beta-hydroxy-succinic acid.
Phallotoxins destroy liver cells by disturbing the equilibrium of G-actin with F-actin, causing it to shift entirely to F-actin. This leads to numerous exvaginations on the liver cell's membrane which render the cell susceptible to deformity by low-pressure gradients, even those of the portal vein in vivo. This is folowed by loss of potassium ions and cytoplasmic enzymes which leads to depletion of ATP and glycogen causing the final downfall of the liver.

Virotoxins

There are six virotoxins:

  • Viroidin
  • Desoxoviroidin
  • Ala1-viroidin
  • Ala1-desoxoviroidin
  • Viroisin
  • Desoxoviroisin

Although they have the same toxicological effects as and appear to be derived from the phallotoxins, the virotoxins are monocyclic heptapeptides, not bicyclic peptides.

Phallolysins

There are three phallolysins that are hemolytically active proteins, but, as previously stated, they are heat and acid labile and do not pose a threat to humans.

Ibotenic acid/Muscimol

A. muscaria var.muscaria Mushroom

    Photo courtesy of Tom Volk.

Ibotenic acid is an Excitatory Amino Acid (EAA) and muscimol is its derivative. These toxins act by mimicking the natural transmitters glutamic acid and aspartic acid on neurons in the central nervous system with specialized receptors for amino acids. These toxins may also cause selective death of neurons sensitive to EAAs.


The Toxic Amanita spp:

The toxicity of the mushrooms on this list is certain; however, there are many others in the Amanita family which have not been positively identified as poisonous or nonpoisonous, please exercise caution in eating any of the these mushrooms.


A. bisporigera

This mushroom is one of a few species known commonly as "Destroying Angels" (A. virosa A. ocreata A. suballiacea A. tenuifolia ). It is smaller than A. virosa , but just as deadly. The only sure way to tell these Destroying Angels apart is by examination of their spores. Their similarity is also a good way to identify mushrooms to avoid: WHITE cap, WHITE gills, WHITE spores, ring and volva = DON'T EAT!! The toxins of this mushroom cause liver and kidney damage and death.

Identification:

CAP:

  1. white, but may discolor at center with age
  2. 1-4" (0.30-10cm) diameter
  3. convex to nearly flat
  4. tacky when wet
  5. smooth

GILLS:

  1. white
  2. free to just reaching stem
  3. crowded

STALK:

  1. white
  2. solid
  3. 1.5-3.5" by 1/4-3/4" (60-140mm by 7-18mm)
  4. ring and volva present

VEILS:

  1. white universal veil (volva), forming cup at base of stem
  2. When young, the Destroying Angels have a marked similarity to puffballs and edible Agaricus mushrooms, so when harvesting Agaricus and puffballs, be sure to check for a volva or its remnants and cut all puffballs in half before eating!
  3. white partial veil, often leaving a torn ring at the top of the stalk

SPORE PRINT:

  1. white

SEASON:

  1. July-October

RANGE:

  1. found in hardwoods east of the Mississippi

A. cothurnata

This mushroom is also known as the Booted Amanita. It is a smaller variety of A. pantherina with a more whitish cap,but similarly poisonous. This mushroom may also be known as A. pantherina var. multisquamosa.

Identification:

CAP:

  1. white, often with yellowish center and white patches
  2. 1-4" (2.5-10cm) diameter
  3. hemispherical to convex, becoming flat to somewhat sunken
  4. sticky and smooth

GILLS:

  1. white
  2. free
  3. crowded

STALK:

  1. oval to round basal bulb
  2. whitish
  3. 2-5" (5-12.5cm) by 1/8-5/8" (0.3-1.5cm)

VEILS:

  1. white universal veil leaving patches on cap, with either bandlike, rolled margin or free rim at tip of stalk
  2. white partial vail leaving pendant ring on mid to upper stalk

SPORE PRINT:

  1. white

SEASON:

  1. July-October

RANGE:

  1. found on the ground in oak, oak-pine, and pine woods from New York to Florida and west to Michigan

A. muscaria var.formosa

This mushroom, the Yellow-orange Fly Agaric is closely related to A. muscaria var. muscaria. Its toxins are not fatal, but can cause sweating, deep sleep and disorientation.

Identification:

CAP:

  1. orange-red to yellowish
  2. 2-6" (5-15cm) diameter
  3. tacky when wet
  4. smooth
  5. loose cottony patches

GILLS:

  1. whitish
  2. free or nearly attached
  3. crowded

STALK:

  1. white, buff, or pale yellow orange
  2. 2-6" (5-15cm) by 1/4-11/4" (0.5-3cm)
  3. sometimes enlargin below to nearly round or slightly rooting basal bulb

VEILS:

  1. universal veil yellowish-buff to tan, leaving patches on cap and concentric bands on lower stalk or rim at tip of bulb
  2. partial veil pinkish-buff, leaving pendant, fragile ring on upper stalk

SPORE PRINT:

  1. white

SEASON:

  1. late June - November; November - February in California

RANGE:

  1. found on the ground under spruce, pine, eastern hemlock, birch, poplar, and oak - common, especially in the east

A. muscaria var.muscaria

<i>A. muscaria</i> var.<i>muscaria</i> Mushrooms

Photo courtesy of Nathan Wilson; nathan@d2.com

<i>A. muscaria</i> var.<i>muscaria</i> Mushrooms

This mushroom, the Fly Agaric is closely related to A. muscaria var. formosa . Its toxins are not fatal, but can cause extreme sweating, delerium and raving. Don't be tricked into drinking the urine of someone who has eaten this mushroom to experience visions- it does not produce the same hallucinogenic effects that its Russian relative does!

Identification:

CAP:

  1. blood red to reddish orange with pyramidal white patches
  2. 2-10" (5-25 cm) diameter
  3. convex to flat, or somewhat sunken

GILLS:

  1. whitish
  2. free or slightly attached
  3. crowded

STALK:

  1. 2-7" (5-18 cm) by 1/8-11/4" (0.3-3 cm)
  2. white to cream
  3. sometimes enlarging to a rounded basal bulb

VEILS:

  1. white universal veil, leaving conical to flat patches on cap and concentric bands on lower stalk, sometimes as rim at tip of bulb
  2. white partial veil, leaving fragile ring on upper stalk

SPORE PRINT:

  1. white

SEASON:

  1. July-October, winter in California

RANGE:

  1. on the ground under pine, spruce, birch, and live oak in the Rocky Mountains and Pacific Coast; rare in east, but reported in New York, Connecticut, and Maine

<i>A. muscaria</i> var.<i>muscaria</i> Mushrooms
<i>A. muscaria</i> var.<i>muscaria</i> Mushrooms

Photo courtesy of Dan Brown

<i>A. muscaria</i> var.<i>muscaria</i> Mushrooms

Photo courtesy of Dr. Dennis Desjardin

A. ocreata

This mushroom is another of the "Destroying Angels" (A. tenuifolia , A. suballiacea , A. virosa , A. bisporigera . It is just as deadly as the rest of them. The only sure way to tell these Destroying Angels apart is by examination of their spores. Their similarity is also a good way to identify mushrooms to avoid: WHITE cap, WHITE gills, WHITE spores, ring and volva = DON'T EAT IT!! The toxins of this mushroom cause liver and kidney damage, and death.

Identification:

CAP:

  1. white, but may become buff-colored at center with age
  2. smooth

GILLS:

  1. white

STALK:

  1. white
  2. ring and volva present

RANGE:

  1. found under oaks in the southwest

VEILS:

  1. white universal veil (volva), forming cup at base of stem
  2. When young, the Destroying Angels have a marked similarity to puffballs and edible Agaricus mushrooms, so when harvesting Agaricus and puffballs, be sure to check for a volva or its remnants and cut all puffballs in half before eating!
  3. white partial veil, often leaving a torn ring at the top of the stalk

SPORE PRINT:

  1. white

SEASON:

  1. winter and early spring

A. pantherina Mushrooms

A. pantherina

This mushroom is commonly known as the Panther. It is related to A. cothurnata and its toxin causes comalike sleep, delerium and raving.

Identification: :

CAP:

  1. brownish with white patches
  2. 1-6" (2.5-15 cm) diameter
  3. tacky when wet
  4. smooth

GILLS:

  1. whitish
  2. free to slightly attached
  3. crowded

STALK:

  1. whitish
  2. 2-7" (5-17.5 cm) by 3/8-1" (1-2.5 cm)
  3. sometimes enlarged to a roundish basal bulb

VEILS:

  1. white universal veil leaving patches on cap and bandlike margin at tip of stalk bulb, typically rolled into stalk, but occasionally free
  2. white partial veil which leaves a persistent ring on upper or mid stalk

SPORE PRINT:

  1. white

SEASON:

  1. June; September-October; November-February in California

RANGE:

  1. found on the ground under conifers from the Rocky Mountains to the West Coast; rare in the east

A. phalloides

This mushroom is the famous Death Cap. The first of the Amanita toxins, phalloidin, was discovered in this mushroom by Lynen and Ulrich Wieland in 1938. This is not to say that it is not possessed of the truly dangerous amatoxins found in the Destroying Angels. The white Death Cap is a rare variety of A. phalloides, known as A. phalloides var. alba (also referred to as A. phalloides var. verna or A. verna ). Besides being nauseating in odor, these are both very deadly mushrooms, quite capable of causing death through liver and kidney failure.

Identification:

CAP:

  1. yellowish-green to greenish brown and darkest at center
  2. 2 1/2-6" (6.5-15 cm) diameter
  3. slightly sticky
  4. smooth

GILLS:

  1. white
  2. more or less free
  3. close

STALK:

  1. whitish to dull greenish yellow
  2. 3-5" (7.5-12.5 cm) by 1/2-3/4" (1.5-2 cm)
  3. enlarging to a basal bulb

VEILS:

  1. universal veil with large, membranous volva
  2. partial veil leaving a membranous, persistent white ring at top of stalk

SPORE PRINT:

  1. white

SEASON:

  1. late September-November in Northeast; November-January in West

RANGE:

  1. found on the ground under conifers and hardwoods from Massachusetts to Virginia, west to Ohio, Pacific Northwest to California, and spreading

A. phalloides var. alba

This mushroom is commonly known as the Death Cap. This white Death Cap is a rare variety of A. phalloides. Besides being nauseating in odor, these are both very deadly mushrooms, quite capable of causing death through liver and kidney failure due to the bicyclic octapeptide, alpha amanitin.

Identification:

CAP:

  1. white with occasional paleyellowish-tan disk
  2. 2 1/2-6" (6.5-15 cm) diameter
  3. slightly sticky
  4. smooth

GILLS:

  1. white
  2. more or less free
  3. crowded

STALK:

  1. whitish to dull greenish yellow
  2. 3-5" (7.5-12.5 cm) by 1/2-3/4" (1.5-2 cm)
  3. enlarging to a basal bulb

VEILS:

  1. universal veil with large, membranous volva
  2. partial veil leaving a membranous, persistent white ring at top of stalk

SPORE PRINT:

  1. white

SEASON:

  1. late September-November in Northeast; November-January in West

RANGE:

  1. found on the ground under conifers and hardwoods mostly in the Northeast

A. suballiacea

Identification:

The description for this mushroom is just about the same as that of A. tenuifolia. It is another white mushroom that falls into the Destroying Angel family (A. virosa , A. bisporigera , A. ocreata , A. tenuifolia ). Not much is known about it, but I wouldn't eat it.

A. tenuifolia

This mushroom is one of a few species known commonly as "Destroying Angels" (A. virosa , A. suballiacea , A. bisporigera , A. ocreata ). The only sure way to tell these Destroying Angels apart is by examination of their spores. Their similarity is also a good way to identify mushrooms to avoid: WHITE cap, WHITE gills, WHITE spores, ring and volva = DON'T EAT!! The toxins of this mushroom cause liver and kidney damage and death.

Identification:

CAP:

  1. white, but may discolor at center with age
  2. 2-3" (6-8cm) diameter
  3. convex to nearly flat
  4. tacky when wet
  5. smooth

GILLS:

  1. white
  2. free to just reaching stem
  3. crowded

STALK:

  1. white
  2. solid
  3. 1.5-3.5" by 1/4-3/4" (70 mm by 7-13 mm)
  4. ring and volva present

VEILS:

  1. white universal veil (volva), forming cup at base of stem
  2. When young, the Destroying Angels have a marked similarity to puffballs and edible Agaricus mushrooms, so when harvesting Agaricus and puffballs, be sure to check for a volva or its remnants and cut all puffballs in half before eating!
  3. white partial veil, often leaving a torn ring at the top of the stalk

SPORE PRINT:

  1. white

SEASON:

  1. ?

RANGE:

  1. found on the ground mostly under oak in Florida

A. verna

Photo courtesy of Dan Brown

Photo courtesy of Dan Brown

This mushroom is one of a few species known commonly as "Destroying Angels" (A. tenuifolia, A. virosa A. suballiacea , A. bisporigera , A. ocreata ). The only sure way to tell these Destroying Angels apart is by examination of their spores. Their similarity is also a good way to identify mushrooms to avoid: WHITE cap, WHITE gills, WHITE spores, ring and volva = DON'T EAT!! The toxins of this mushroom cause liver and kidney damage and death.

Identification:

CAP:

  1. white, but may discolor at center with age
  2. 2-5" (5-12.5 cm) diameter
  3. convex to nearly flat
  4. tacky when wet
  5. smooth

GILLS:

  1. white
  2. free or attached
  3. crowded

STALK:

  1. white
  2. solid
  3. 3-8" (7.5-20 cm) by 1/4-3/4" (0.5-2 cm)
  4. ring and volva present

VEILS:

  1. white universal veil that leaves a large membranous, persistent volva
  2. When young, the Destroying Angels have a marked similarity to puffballs and edible Agaricus mushrooms, so when harvesting Agaricus and puffballs, be sure to check for a volva or its remnants and cut all puffballs in half before eating!
  3. white partial veil, often leaving a large torn ring at the top of the stalk

SPORE PRINT:

  1. white

SEASON:

  1. late June-early November

RANGE:

  1. found on the ground in mixed woods or in grass near trees throughout North America

A. virosa

This mushroom is another of a few species known commonly as "Destroying Angels" (A. tenuifolia , A. suballiacea , A. verna , A. bisporigera , A. ocreata ). The only sure way to tell these Destroying Angels apart is by examination of their spores. Their similarity is also a good way to identify mushrooms to avoid: WHITE cap, WHITE gills, WHITE spores, ring and volva = DON'T EAT!! The toxins of this mushroom cause liver and kidney damage and death.

Identification:

CAP:

  1. white, but may discolor at center with age
  2. 2-5" (5-12.5 cm) diameter
  3. convex to nearly flat
  4. tacky when wet
  5. smooth

GILLS:

  1. white
  2. free or attached
  3. crowded

STALK:

  1. white
  2. solid
  3. 3-8" (7.5-20 cm) by 1/4-3/4" (0.5-2 cm)
  4. ring and volva present

VEILS:

  1. white universal veil that leaves a large membranous, persistent volva
  2. When young, the Destroying Angels have a marked similarity to puffballs and edible Agaricus mushrooms, so when harvesting Agaricus and puffballs, be sure to check for a volva or its remnants and cut all puffballs in half before eating!
  3. white partial veil, often leaving a large torn ring at the top of the stalk

SPORE PRINT:

  1. white

SEASON:

  1. late June-early November

RANGE:

  1. found on the ground in mixed woods or in grass near trees throughout North America

Toxic Amnita Mushrooms: symptoms and cures

The Amanita spp. are a genus of mushrooms containing a few species famous for their toxicity. There are many edible amanitas, but eating the wrong one can get you into heaps of trouble, not to mention the delerium, vomiting, diarrhea, cramps, liver failure or death you may experience. Most poisonings tend to occur in people from foreign countries who pick Amanitas that look "just like" those yummy ones they ate at home or to overconfident novice mycophagists (people who wild mushrooms) who have not bothered to properly identify their mushrooms. So, if you plan to hunt the wild mushroom, make sure to arm yourself with the proper knowledge and only eat a wild mushroom in a foreign country based upon identification in that country's field guide, not a North American guide. Be sure that you use a guide and don't listen to any old wives' tales about how to tell edible mushrooms from poisonous ones.

As knowledge is your best defense in avoiding Amanita poisoning when practicing wild mushroom gathering, it is wise to become familiar with all the parts of a mushroom. The Amanita are primarily identified by the presence of a universal veil completely covering immature mushrooms, a volva or cup around the base, a partial veil which may be in the form of a ring on the upper stalk, free to slightly attached white/cream colored gills, and a white spore print. Unfortunately, some of these identifying characteristics are delicate and can be removed by rain, wind or animals. This is only a major problem if you are trying to eat the edible Amanitas. It is essential that all the identifying markers be in place to differentiate between deadly Amanitas and edible ones. If after all this, you still insist on eating Amanitas, then you're on your own!

The Symptoms:

  1. Amatoxins - The symptoms of amatoxin poisoning in humans are a ghoulish series of four phases, beginning with the not-too-alarming latency phase of 6-12 hours. This is followed by the gastrointestinal phase, where the human gets its first inkling that something is not quite right. The gastrointestinal phase consists of diarrhea, dehydration, vomiting and, not surprisingly, abdominal pains. The third phase begins with the patient feeling deceptively better off (another latency period) until the fourth and final phase hits. The final phase consists of the final degradation of the liver and kidney until, between the fourth and eighth day after ingestion, the patient lapses into hepatic coma combined with renal failure, ending in death. All this from a dose of 0.1 mg/kg body weight or even lower. That's not much mushroom to kill a person!
    • cholera-like diarrhea
    • dehydration
    • vomiting
    • abdominal pains
    • drop in coagulation factors
    • increase in liver enzymes (SGOT,SGPT,LDH)
    • hepatic failure
    • encephalopathy
    • kidney damage
    • DEATH due to combined liver and renal failure
  2. Phallotoxins & Virotoxins
    • severe swelling of the liver
    • cessation of bile flow
  3. Phallolysins
    • The phallolysins are labile against acids and heat, and do not contribute to human Amanita poisoning.
  4. Ibotenic acid (and possibly its derivative, muscimol)
    • central nervous system depression
    • ataxia
    • hysteria
    • hallucinations - even worse this amino acid may drive you to drink urine.

The Cures:

  1. The first step in detoxifying amatoxins from the system involves mechanical purification of the blood (hemodialysis, hemoperfusion, or forced diuresis), then interruption of the enterohepatic circulation by insertion of a duodenal tube, silymarin or penicillin.
  2. If the above treatments were not enough, the victim may still have to endure a liver transplant. As this is expensive, painful and not without complications itself, prevention must be emphasized as the best solution to Amanita poisoning.
  3. Antamanide is a nontoxic monocyclopeptide found in A. phalloides that competes with the phallotxins for the membrane proteins involved in the uptake of the phallotoxins. Unfortunately, antamanide only is effective when ingested 1 to 2 hours prior to or within 20 minutes of ingestion of the phallotoxins (at least in mice). So it's a rather ineffective cure at best.
  4. Silymarin, a mixture of components in the milk thistle, also alleviates the toxicity of phallotoxins, but again is hampered by time constraints.
  5. Rifampicin reduces the rate of phallotoxin uptake in the liver, but with the same problems found with silymarin and antamanide.
  6. Bile salts have a great effect in reducing phalloidin uptake in vitro, but, as the phallotoxins cause the cessation of bile flow, this is a really ineffective cure.
  7. Liver-damaging substances, such as carbon tetrachloride, can be used to stop uptake of phallotoxins, but this "cure" is not much better than the affliction.

Other Mushrooms Containing Amatoxins and Phallotoxins:

  1. Galerina marginata
  2. G. venenata
  3. Lepiota brunneoincarnata
  4. L. helveola
  5. L. josserandii

References:

Bessete, A.E.1988. Mushrooms of the Adirondacks: A Field Guide. North country books, Inc. Utica, NY. 145p.

Fischer, D.W. and Bessette, A.E.1992. Edible Wild Mushrooms of North America: A Field to Kitchen Guide. University of Texas Press, Austin, TX. 254p.

Jenkins, D.T. 1986. Amanita of North America. Mad River Press Inc. Eureka, CA. 198p.

Lincoff, G.H. 1981. National Audubon Society Field Guide to North American Mushrooms. Alfred A. Knopf, New York, NY. 926p.

Norton, S. 1996. Toxic Effects of Plants. Pp. 841-854. In: Casarett & Doull's Toxicology: The Basic Science of Poisons, Fifth Edition. C.D. Klaassen, Ed. McGraw-Hill Companies, Inc. New York, NY.

Weiland, T., and Faulstich, H. 1983. Peptide Toxins from Amanita. Pp. 585-635. In: Handbook of Natural Toxins, Volume I: Plant and Fungal Toxins. R.F. Keeler and A.T. Tu, Ed. Marcel Dekker, Inc. New York, NY.

General Mushroom Links of Interest:

MykoWeb
MycoFAQ
Mycelium
The FDA's mushroom poisoning info page
mycoElectronica
This sounds cool: a mushroom foray in Vermont