Principles lec 7 2013

Case study of the mycotoxin zearalenone 17 important

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Unformatted text preview: served following toxicant exposure. Case study of the Mycotoxin Zearalenone 17 important for agriculture Mycotoxins “We live with them but we must learn to recognize when they are causing adverse effects (Toxicosis)” Mycotoxins 18 Definitions: 1. Mycotoxin - Myco = fungus Secondary fungal metabolite (not essential for mold survival produced under specific environmental conditions & cause adverse health effects often produced as a defensive mechanism for environmental conditions it is encoutering talk about pests, humidity, pesticides, (fungus is specific to host, so different crops have different fungus) 2. Mycotoxicosis - mycotoxin produced disease ; fungus no longer involved Fungal Growth 19 Fungal growth factors What determines if a fungus grows? 1. Weather 2. Growth 3. Man 4. Host Plant Temperature and Humidity (>70%) Competition Other Fungi (non-toxigenic fungi) Cropping practices (damage, fungicides) Type & “species” Common crops: cereals, grain, corn, cotton seeds sorghum, nuts Less common: grasses (fescue, dallis, rye) ALSO!! Can encounter from animal products (contaminated feed) Mycotoxin Production Factors 20 Conditions for fungus to produce a mycotoxin are “stringent.” 1. Substrate Type: field fungi or storage fungi 2. Moisture >10% humidity >70% 3. Temperature 4. Oxygen “Therefore mycotoxin production is seasonal and environmentally dependent!” Case Study Zeralenone (How to look at an Interaction) 21 Fungus: Fusarium roseum * & F. moniliforme Substrate: Corn Barley, wheat, oats, hay Conditions: High moisture >23% Temperature: High to Low Zeralenone 22 Zeralenone Estradiol Estrogen mimic: structurally and chemically similar Zeralenone 23 Target: “Estrogen Receptors” Mechanism: - Binds reversibly (non convalently) with receptor: - Stimulating response, increase in activity Interaction: - Specific (Binds one kind of receptor) over stimulation lots more estrogenic affects vaginal swelling cellular adema Pathogenesis: - Altered function resulting in estrogen receptor over stimulation -Pathology includes swollen reproductive organs, cellular edema (fluid leakage), hyperplasia in uterus Clinical Signs 24 Clinical Signs: Hyperestrogenism Hyperplasia Swine: Prepubertal Female Reproductive organs: Vagina and Swelling + edema (1 ppm) Hyperemia Uterus Thickening + Hyperplasia Edema...
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This document was uploaded on 04/07/2014.

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