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Fungal Ecology |
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- Distribution -- fungi are everywhere!
- Energy source -- all heterotrophs
- Soil -- major source of fungi
- Interaction with plants --mycorhizia
Secondary metabolites
+ Selective advantage?
+ Antibiotics -- penicillin, cephalosporins
+ Other drugs -- cyclosporine
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Fungal Structure |
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Molds -- growth as filaments
- Septate hyphae
- Aseptate hyphae
- Reproduce by spores
Yeasts
- Single-cell growth
- Reproduce by budding
Dimorphism
- Mold -- soil Yeast -- tissue
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Fungal Cell Wall |
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- Multi-layered
Polysaccharide subunits
- Mannans
- Glucans
- Chitin
- Protein fibrils
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Fungal Reproduction |
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- Asexual (imperfect stage) -- Spores or fragmentation of hyphae
Sexual (Perfect stage) - specialized spores
- Ascomycetes
- Basidiomycetes
- Zygomycetes
-Sexual stage important for taxonomy - not usually seen in diagnostic lab
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Identification and Culture |
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Histopathology - need to use special stains
- Silver stain
- PAS
Direct microscopy -- look for fungal elements
Culture - use fungal media
- Sabourauds
- Potatoe dextrose
- Cornmeal agar
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Fungal Taxonomy |
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- Separate Kingdom
Classification based on sexual stage
- Spores
- Specialized hyphae
Single fungal species can have different names for perfect and imperfect stages
- Ex.: Cryptococcus neoformans - imperfect
- Filobasidiella neoformans - perfect
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