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The Chemistry of Mycotoxins. UMD Chemical Ecology TIP Group 2A. What is a Mycotoxin?. Mycotoxins are toxic chemicals produced by fungi (molds), that cause a wide variety of harmful effects.[1]

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the chemistry of mycotoxins

The Chemistry of Mycotoxins

UMD Chemical Ecology

TIP Group 2A

what is a mycotoxin
What is a Mycotoxin?
  • Mycotoxins are toxic chemicals produced by fungi (molds), that cause a wide variety of harmful effects.[1]
  • When ingested, they are known to cause: general toxic affects, immune system suppression, mutations, cancer, and teratogenic affects (mutations in offspring). [1]
  • Because many fungi are not well studied and not all species have been identified some researchers suggest that there could potentially be 300,000 mycotoxins. [2]
  • There is no confirmed reason for the existence of mycotoxins. [2]
why are they important

Why are they important?

They are usually ingested in contaminated food

They can cause cancer, birth defects, liver damage, and nervous tissue damage, etc.

Most are not destroyed in normal cooking procedures.

Usually no treatment for mycotoxin poisoning

Mycotoxins have played an important role in some historical events (St. Anthony’s fire, Yellow rain, others)

Annual losses in the USA and Canada, arising from the impact of mycotoxins on the feed and livestock industries, are of the order of $5 billion. [1]

slide4

http://www.foodtech-international.com/papers/images/mycotoxins/figure1.gifhttp://www.foodtech-international.com/papers/images/mycotoxins/figure1.gif

how do mycotoxins cause damage to living organisms
How do Mycotoxins cause damage to living organisms?
  • Mycotoxins have unique chemical structures. These structures react/interact with the chemicals in living organisms causing harm.

http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/21738.jpg

functional groups
Functional groups
  • A functional group is a group of atoms that bonds to a carbon chain which changes the chemical properties of the carbon chain.
  • Functional groups react in predictable ways
common functional groups
Common Functional groups

http://www.chemheritage.org/EducationalServices/pharm/tg/asp/ester/ester01.htm

how do mycotoxins cause other effects
How do mycotoxins cause other effects?
  • Trichothecenes interfere with the active site of peptidyl transferase on ribosomes. This inhibits protein synthesis. [4]
  • The special chemical structure that allows trichothecenes to bond to peptidyl transferase is the epoxytricothecene ring. [4]
  • Since proteins (enzymes) catalyze almost every reaction in the body, not being able to produce enzymes can be very harmful.

Epoxytricothecene ring

mycotoxins and livestock
Mycotoxins and livestock

http://www.thebeefsite.com/articles/1808/mycotoxins-in-cattle

how do mycotoxins cause cancer
How do mycotoxins cause cancer?
  • The chemical structure of some myxotoxins allows them to fit in between (intercalate) the double helix of DNA. This causes problems for DNA replication. Mutations in genes that control the cell cycle can lead to cancer.
  • If the mutations happen in sperm and eggs they can cause birth defects or mutations in a person’s offspring.

http://4.bp.blogspot.com/_DZH2cmCoois/RqDJo5IavwI/AAAAAAAACl4/gIwPKe10FME/s400/DNA_intercalating_agent.jpg

aflatoxins
Aflatoxins

Species: Genus Aspergillus, A. Flavus, A. parasiticus, A. Nomius

Affected foods: peanuts, maize, cottonseeds, spices

Aflatoxins M1, M2: Metabolites of aflatoxins B1 and B2:

Affects Milk and dairy products

aflatoxins continued
Aflatoxins Continued

Interesting facts:

  • No animal species is immune to the acute toxic effects of aflatoxins including humans.
  • Aspergillus can grow and produce aflatoxins on black pepper.
  • In 1960 approximately 100,000 turkeys died as a result of eating peanut in their food that had aflatoxin. (Orginally thought to be caused by a virus and named Turkey X disease)
  • Turkey X disease led to more research on mycotoxins.
ochratoxin a
Ochratoxin A

Species: P. Verrucosum and A. ochraceus

Food affected: Cereals, coffee beans, and grapes.

Interesting Facts: Ochratoxin can be transmitted from pork to humans by eating pork that is fed with contaminated food.

zearalenone
Zearalenone

Species : Fusarium roseum, F.graminearum, F. poae, F. culmorum

Food affected: corn, wheat, barley, oats

Interesting facts:

  • Zearalenone has estrogenic effects.
  • Fusarium species grows and produces mycotoxins at times of high moisture 22% - 25%, and alternating high and low temp. (7-21ºC )
patulin
Patulin
  • Species: in the genus Aspergillus and Penicillium
  • Food affected: Apple juice and apple related products
  • Interesting Facts: One of the few mycotoxins associated with apples.
fumonisin b 1 b2
Fumonisin B-1 B2
  • Species: Many species from the Fusarium genus. Ex: F. verrucosum, F. proliferatum
  • Affected foods: Maize (corn), wheat and other cereals
  • Interesting facts: Inhibits an enzyme causing liver and kidney problems.
trichothecenes
Trichothecenes

Trichothecene structure

  • Species: Many species from the Fusarium genus. Ex: F. sporotrichioides, F. poae, F. graminearum, F. culmorum.
  • Foods affected: Maize (corn) Fusonisin toxin, Cereals, wheat
  • Interesting facts: Can be produced in indoor environments, which can contribute to health problems among unsuspecting building occupants.

http://en.wikipedia.org/wiki/Trichothecenes

trichothecenes cont
Trichothecenes Cont.
  • The damage to the immune systems of both rats and human could have caused decreased immune system response, which could have been a contributing factors that led to the high mortality during the Bubonic Plague. [4]
  • Mycotoxin (T-2) caused an epidemic outbreak when grain that was supposed to be harvested in the fall was harvested in the following spring due to WWII. This extra time allowed fugal growth that contaminated the grain. [4]
trichothecenes cont19
Trichothecenes Cont.
  • In 1981 secretary of state Alexander Haig alleged the Soviet Union supplied trichothecenes which were used as chemical weapons in Vietnam war. This was later disputed. [4]
ergot
Ergot
  • Species: Claviceps purpurea, and Aspergillus and Penicillium
  • Affected foods: rye, barley, wheat, and oats
  • Interesting facts:
  • First documented case of ergot poisoning was in 857. [5]
  • Responsible for St. Anthony's fire. Monks of the order of St. Anthony the Great specialized in treating ergotism victims. Some symptoms of ergotism are hallucinations and “rotting” of limbs which often lead to amputation. [5]
  • Ergot contains a chemical precursor to lysergic acid (LSD).
ergot continued
Ergot Continued
  • In 944 AD, in southern France, 40,000 people died of ergot poisoning. [5]
  • Some people have speculated that ergot poisoning could have caused the strange behavior described during the Salem Witch Craft Trials. (you will research this later) [5]
functional group assignment
Functional Group Assignment
  • Identify the functional groups in mycotoxins provided.
mycotoxin assignment
Mycotoxin Assignment
  • You are to read the articles provided by your teacher and answer the questions, followed by a discussion.
extension assignment
Extension Assignment
  • Research one of the following mycotoxin topics in greater detail and write a one page summary.
  • Turkey X disease
  • St. Anthony’s fire
  • Yellow Rain
  • Salem Witch Craft Trials
  • Mycotoxins and biological weapons
  • Mycotoxins and the discovery of LSD
  • Mycotoxins and Religion- What effect did mycotoxins have on historical religious activity? Give three examples
interesting mycotoxin links
Interesting mycotoxin links
  • Yellow Rain –

http://cns.miis.edu/npr/pdfs/81tucker.pdf

http://cns.miis.edu/stories/020805.htm

  • Turkey X disease and yellow rain

www.botany.hawaii.edu/faculty/wong/BOT135/Lect09.pdf

  • Historical mycotoxins, Ergot emphasis http://www.botany.hawaii.edu/faculty/wong/BOT135/LECT12.HTM
resources
Resources
  • [1] Agriculture and Consumer protection [online] www.fao.org/DOCREP/005/Y1390E/y1390e02.htm
  • [2] Top ten [online] www.engormix.com/the_top_ten_most_e_articles_198_GDL.htm
  • [4] Rocha O, Ansari K, Doohan F. 2005. Effects of trichothecene mycotoxins on eukaryotic cells: A review. Food Additives and Contaminants. 22[4]:369-378.
  • [4] www.botany.hawaii.edu/faculty/wong/BOT135/Lect09.pdf
  • [5]http://www.botany.hawaii.edu/faculty/wong/BOT135/LECT12.HTM http://www.botany.hawaii.edu/faculty/wong/BOT135/LECT12.HTM