Lecture 3: Poisonous Fungi Flashcards
Aflatoxins
among the most dangerous fungal toxins; produced by certain strains of Aspergillus flacus and A. parasticus
Why are aflatoxins a potential health hazard?
since agriculutiral products may be contaminated both before and after harvest
- toxins remain in food long after the fungus had died and aflatoxin-contaminated food is often not visibly moldy
What are the most commonly affected crops?
corn, peanuts, cottonseed, rice, nuts, cereal grains, and fruits
Aflatoxins from contaminated domestic animal feed are retained in..
eggs, milk, and meat, and so passed on to persons consuming these foods.
Aflatoxins are a potent carcinogen and so..
interact directly with DNA to strongly affect the transcription of genetic information. The resultant metabolites are important isk factors for liver tumours and liver cell degeneration - children are particularly susceptibel to aflatoxin poisoning
Ergot
A fungal parasite of some cereal grains, particularly rye) and forage grasses; is particularily abundant in wet summers
What does the ergot fungus attack?
maturing cereal grains, producing characterisit purplish-black “fruiting bodies”
What are the fruiting bodies called?
scherotia
How is ergot normally ingest by humans?
contaminated milled flour - baking does NOT destroy the the poisoning alkaloids
Daily ingestion of small amounts of ergot results in..
chronic poisoning
when was accidental poisoning of ergot common in europe?
in the middle ages, particularly where rye bread was eaten
What is St. Anthony’s Fire?
symptoms of ergot poisoning.
When was the earlies reliabel record of a SERIOUS outbreak of ergot poisoning?
857 CE in the Rhine Valley of Germany, but ergotsim almost certainly occured prior to this date
Ergot outbreak in 994
killed an estimated 40,000 ppl in France
Ergot outbreak in France in 1039
led the philanthropist Gaston De la Vallorie to establish a hospital dedicated to Saint Anthony for the treatment of victims of ergotsism
How did ergot poisoning lead to the flourish of the church in Europe?
370 hospitals often associated with the chuch were established. Ppl with ergot poisoning sought sanctuary and protection in the Church where they were fed light coloured bread not infested with ergot, when their symptoms disappeared it confirmed the healing powers of the church.
Two types of ergotsim
Gangrenous ergotism
convulsive ergotism
Gangrenous ergotism symptoms
tingling sensation in the extremities, vomiting and diarrhea, within a few days extremeites become gangrenous and hallucinations occur; eventually entire limbs are affected resulting in excrciaing pain as blood flow to the extremities declines; sometimes the limbs eventually separate from the body
Conculsive ergotism symptoms
similar to gangrenous but produces painful spasms of the limb muscles, severe epileptic convulsions and eventually death
Two groups of active alkaloids in ergot
- ergonovine and ergotamine
2. lysergic acid (LSD) derivatives
ergonovine and egotamine cause..
arterioles to contract, contractions of smooth muscle, particularly that of the digestive tract
What symptoms does the first group of ergot alkaloids cause?
the characteristic symptoms of ergotism: gangrene of extremities, vomiting, muscle twitching and staggering gait
What symptoms does the LSD derivatives cause?
visual-auditory hallucinations
What caused the suggestion of the link between ergot intoxication and religous visions that were frequently reported during the middle ages?
because during the middle ages, the chruch embraced all aspects of European life, leading to the speculation that ergot-induced hallucinations would often have been manifested as religious imagery
What else can ergot explain in Europe and colonial America?
Witchcraft
Where did the most famous “witch trial” occur?
Purtian colony of Salem, Massachusetts in 1692
What occurred in the most famous witch trial?
Children and young adults reported convulsions, mental disturbance, and perceptual distortions- which were associated with witch craft – lead to the hanging of 20 men and women accused of “demonic possession “ of the affected children.
It was thought that Salem witch trials were driven primarily by..
“Group hysteria”
Researchers have noted association with witch symptoms with..
Ergot poisoning
of researchers have strong correlation of wet summers and…
Reports of demonic possession and witchcraft
Other evidence for ergot poisoning causing witch craft in Norway and Scotland?
Witch persecution has only occurred where rye was grown and used for bread making
How was ergot used as medicine in Europe
During childbirth since it stimulated contractions of uterine muscle; to control uterine hemorrhaging
Not used today
How many pounds of ergot was imported to the USA in late 1940 for expectant mothers
2000kg
What is the most poisonous mushroom? what are its killing stats
Death Cap
over 90% of all mushroom poisoning fatalities in Eurasia and north america
why do fatalities due to death cap occur?
because death cap is commonly mistaken for edible mushroom species - Asian straw mushroom
how long is the latency period to the onset of symptoms from death cap?
10 hr
What are the symptoms of death cap poisoning?
initial - abdominal cramping, nausea, vomiting lasting about a day
appearent remission the next day but then followed by severe intestinal pain as well as liver and kidney failure
Death may occur if the patients is not immediately treated
what is the active compound in death cap and what does it do?
complex alkaloid amanitin and it causes cell destruction
other poisonous mushrooms
gymnomitra esculenta - poisoning by cell destruction
entoloma sinuatum and boletus satanas - poisoning by enteritis or inflammation of the small intestine
– cases are rare since they are rarely mistaken for edible mushrooms
