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Mycotoxins : Gibberella zeae. John Carlo O. Macuja Jackielyn 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.
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Mycotoxins:Gibberellazeae John Carlo O. Macuja Jackielyn B. Ocbina III-BSCT
Gibberellazeae • Also known as Fusariumgraminearum • Kingdom: Fungi • Phylum: Ascomycota • Class: Sordariomycetes • Subclass: Hypocreomycetidae • Order:Hypocreales • Family:Nectriaceae
Gibberellazeae • 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
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.
Response to vomitoxin appears to occur through the central nervous system. • Vomitoxinbelongs 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, abortionand 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