Mycotoxins : Gibberella zeae
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Transcript of Mycotoxins : Gibberella zeae
Mycotoxins:Gibberella zeae
John Carlo O. MacujaJackielyn B. Ocbina
III-BSCT
Gibberella zeae
• Also known as Fusarium graminearum• Kingdom: Fungi• Phylum: Ascomycota• Class: Sordariomycetes• Subclass: Hypocreomycetidae• Order:Hypocreales• Family:Nectriaceae
Gibberella zeae
• This ascomycete fungus is the causal agent of head blight of wheat
• It has caused an estimated several billion dollars worth of damage in the US alone over the past decade.
• In head blight of wheat, newly emerging wheat heads (the fruits, which contain the seeds, the part that we eat) are infected by forcibly discharged, airborne ascospores released by G. zeae .
• The spore germinates on a wheat kernel, penetrates, and grows down through the stalk.
• Once a certain fungal mass is reached, fruiting structures penetrate though the wheat's stomates (the breathing apparatus on its leaves).
• These fruiting structures may be either asexual or sexual
Fusarium head blight
Mycotoxins
• deoxynivalenol• zearalenone
deoxynivalenol
• Also known as Vomitoxin• a type B trichothecene, an epoxy-
sesquiterpenoid.• This mycotoxin occurs predominantly in grains
such as wheat, barley, oats, rye, and maize.
vomitoxin
• Response to vomitoxin appears to occur through the central nervous system.
• Vomitoxin belongs to a class of mycotoxins (tricothecenes) which are strong inhibitors of protein synthesis.
• Exposure to vomitoxin causes the brain to increase its uptake of the amino acid tryptophan and, in turn, its synthesis of serotonin.
• Increased levels of serotonin are believed to be responsible for the anorexic effects of DON and other tricothecenes.
• Human foods: Vomitoxin is not a known carcinogen as with aflatoxin. Large amounts of grain with vomitoxin would have to be consumed to pose a health risk to humans.
• The U.S. Food and Drug Administration has established a level of 1 ppm (parts per million) restriction of vomitoxin.
• Companion animals: Dogs and cats are restricted to 5 ppm and of grain.
• Livestock and farm animals: In animals and livestock, vomitoxin causes a refusal to feed and lack of weight gain when fed above advised levels. Restrictions are set at 10 ppm for poultry and cattle.
Zearalenone
• Zearalenone is the primary toxin, causing infertility, abortion and other breeding problems in swine.
• The main concern is that zearalenone is a naturally occurring estrogen
• It causes hormonal effects in animals such as the pig