Lecture 13: Mycotoxins

What are the major mycotoxins?

1. Aflatoxins 2. Ergot alkaloids 3. Fumonisins 4. Ochratoxin 5. Patulin 6. Trichothecenes

What are mycotoxins?

1. low-molecular weight natural products (small molecules) produced as secondary metabolites by filamentous fungi

Symptoms of mycotoxicoses depend on:

1. type of mycotoxin 2. amount and duration of the exposure 3. age, health and sex of individual

Aflatoxins are produced by at least _____________ Aspergillus spp.

10

Patulin discovered in _____.

1943

Fusarium verticillioides was discovered in _________ (year) and causes _____________ _____________(ELEM)

1988 Equine leukoencephalomalacia -liquefactive necrotic lesions in the brain of tissue of horses

Aflatoxins: Biosynthesis involves ________ clustered genes.

25

Aflatoxins: strictly regulated in agricultural commodities ____________ ____________

4 ng/g (EU) 20 ng/g (USA)

Fumonisins: 16 types are:

A1-A4 B1-B4 C1-C4 P1-P4

Aflatoxins: Predominantly hepatic carcinogens. ________________ (statement)

AFB1 most potent liver carcinogen discovered

What is the most potent naturally occurring carcinogen known? (type of mycotoxin)

Aflatoxin B1

Aflatoxin induced disease=_____________________

Aflatoxoticoses

Which mycotoxin was linked to the consumption of a moldy Brazilian peanut meal? Name genus and species too.

Alfatoxin Aspergillus flavus (tip: named after genus)

The most major compound of the Aflatoxin?

Alfatoxin B1

What is the most important polyketide-derived family mycotoxins?

Alfatoxins

Trichothencenes: What type of condition causes T2 toxin?

Alimentary toxic aleukia, pp109

If you found out a patient becomes ill from a mycotoxin called Ochratoxins. Which fungal genera(s) produce ochratoxins?

Aspergillus & Penicillium

What type of Aspergillus causes ochratoxins?

Aspergillus ochraceus & Aspergillus carbonarius (coffee beans & grapes)

Fumonisins: ________ is the the most prevalent type (70%)

B1

Main types of Alfatoxins. (not in red, in blue, might be important)

B1, B2, G1, G2

Trichothecenes: Dermal exposure include: burning pain, ________ , _________ and oral may lead to vomiting and diarrhea.

Blisters and redness

Fumonisins are usually growing on ?

Corn

What does FDA stand for?

Federal Food and Drug and Cometics Act

What fungal genus is related to pulmonary porcine edema (PPE)?

Fumonisins

Which fungal genus cause equine leucoencephalomalacia (ELEM) in horses?

Fumonisins

Fumonisins are caused by which fungal genus? (pp 77)

Fusarium

What is the genus and species name of the fungal organism that creates the fumonisn mycotoxin?

Fusarium verticillioides

Fumonisins: Negative health impacts:

Humans (esophageal cancer, neural tube defects) Equines and rabbits (ELEM) Swine (pulmonary edema)

Ergot alkaloids belong to which large category of alkaloids? (pp 62 more info)

Indole

Alfatoxins: derivatives: "milk toxins" (not in red, in blue)

M1, M2

Mycotoxins are much less important than mushroom poisons and more known by the public. True or False (fix).

More important Less known

Trichothecenes are produced by which genera of fungi?

Multiple genera of fungi

Does the mycotoxin have any known connections to disease outbreaks?

No

Which fungal mycotoxin has antibiotic properties? carcinogen? mutagen & caused chromosome damage in bio systems?

Patulin

Ochratoxin: which mycotoxin is the most abundant food contaminating?

Penicillium verrucosum

Patulin is a mycotoxin caused by which genus?

Penicillium....& Aspergillus, paceilomyces, byssochlamys

Alfatoxins: Alternate types: hydroxy group (not in red, in blue)

R0, RB1, RB2, H1, B3

Trichothecene mycotoxins?

Saratoxin H T-2 Toxin Deoxynivalenol

Number one nickname for ergotism=________________ (pp 68 contains more symptoms)

St. Anthony's Fire

Fumonisins: The A-types appear not to be ____________.

Toxic

Which mycotoxin is related to chemical warfare as the components of "yellow rain" and thought to cause the worst complaints associated with "sick building syndrome?"

Trichothecenes: they both are controversial topics.

Are ochratoxins B, C alpha and beta similar to OTA, but require much higher dose levels. True or False (pp 89)

True

Patulin was discovered as an "antibiotic" not as a mycotoxin. True or False

True

Symptoms of Trichothecenes among....

animals and humans

Vocab of Mycotoxicoses

are the diseases caused by coming in contact with mycotoxins (in diet)

Vocab of Mycotoxin

are the toxic compounds produced by molds

What are the symptoms of ergotism divided into?

convulsive and gangrenous symptoms

What is the function of Alternaria toxin? a) Tenuazonic acid=protein sysnthesis inhibitor b) AA-toxins=sphingolipid metabolism inhibitor c) atranone=inflammatory agent d) a and b e) all the above

d

Chronic toxicity

describes the adverse effects from REPEATED exposures, often at low levels, to a substance over a PERIOD of months or years

Acute toxicity

describes the adverse effects of a substance that result either from a SINGLE EXPOSURE or from SEVERAL exposures in SHORT PERIOD OF TIME

Mycotoxicoses

diseases caused by exposure to mycotoxins

What is the function of Stachybotrys toxins? a) Tenuazonic acid=protein synthesis b) Atranone=inflammatory agent c) saratoxin=protein synthesis inhibitor d) all the above e) b & c

e

Ergotism is the disease caused by the ingestion of the alkaloids produced by Claviceps purpurea fungus that infects rye and other cereals. What are alternative names for ergotism?

ergotoxicosis ergot poisoning SAINT ANTHONY'S FIRE

Ergot Alkaloids are produced by which fungi?

genus: Claviceps + species purpurea

What is the global economic impact of Aflatoxins?

hundreds of millions of dollars

What does fumonisin do in the body?

interferes with sphingolipid metabolism

Fumonisins: Global economic impact

less than that of aflatoxins, but still significant

What is the definitive structural element of ergot alkaloids? (pp 62 more info)

lysergic acid

Aflatoxins: Non-production results from ___________ in, and/or loss of, genes within the pathway

mutations

Not all toxic compounds produced by fungi are called ____________________

mycotoxins

Mold (micro) make ______________ while mushrooms (macro) make _________________.

mycotoxins mushroom poisons

Types of Ochratoxin A (OTA):

neurotoxic nephrotoxic teratogenic hepatotoxic immunotoxic carcinogenic

Penicillium verrucosum is known for causing which mycotoxin? Found on cereals (corn, barley, oats, rye, wheat)

ochratoxins

How many countries have regulations established to protect the consumer from harmful effects of mycotoxins?

one hundred

Aflatoxin: most susceptible creatures?

poultry and trout

Where has ochratoxin been found?

range of raw & processed: cereals, coffee, dried fruits, wine beer, coca, nuts, beans, peas, bread and rice In meat--> pork & poultry (from contaminated feed)

Ergot alkaloids are found within morphological structure called ________________. + grows on rye

sclerotia

Ergotism: convulsive symptoms are........ (might be useful)

seizures spasms diarrhea paresthesias itching mental: mania, or psychosis, headaches, nausea & vomiting gastrointestinal effects precede central nervous system effects

Mycotoxicology

study of mycotoxins

The _________ and the _________ of the metabolite are both important.

target concentration

Most mycotoxins are ___________.

tasteless

Different mycotoxins cause different _______________.

toxic effects

Trichothecene: Ocular exposure might result in blurred vision and inhalational exposure might cause nasal irritation and cough. TRue or false

true

Where is patulin found?

unfermented apple and grape juice & field crops

Ergotism: Gangrene results in.. (might be useful)

vasoconstriction induced by erotamine-ergocristine alkaloids of the fungus. peeling of skin, weak peripheral pulses, loss of peripheral sensation, edema & death & loss of affected tissue

Trichothencenes: Systemic sysptoms?

weakness, ataxia, hypotension, coagulopathy and death