Fungi Flashcards
Saprophyte
Organism that lives off of dead material
Asexual repro elements
conidia
Sexual repro elements
spores
Why are fungi harder to kill than bacteria?
Eukaryotic (toxic to them is usually toxic to us)
Two basic fungal morphologies:
yeasts
molds
How do fungi differ from animal cells?
- Cell membrane contain ergosterol (not cholesterol); Ergosterol can be eliminated from membrane without affecting our cholesterol
- Cell wall (made of chitin)
Yeast are __-cellular.
Uni
Yeast reproduce asexually by:
budding
Yeast reproduce sexually by:
ascospores (sacs containing 4 spores)
Molds are __-cellular.
Multi
Structure characteristic of mold.
Hyphae.
Mycelium
Intertwines mass of hyphae
Mold structure used for growth
vegetative hyphae
Mold structure used for reproduction
aerial hyphae
Dimorphic fungi can be both:
Under what circumstances does each grow?
yeast (in tissue and at 37C) and mold (room temp)
Classification of fungi that do not seem to have a sexual stage
Deuteromycetes
3 Problems caused by fungi:
allergies
mycotoxicoses (e.g. mushroom poison)
*mycoses (true infections)
What must occur in order for a fungus to infect you?
It must cross surface barrier (inhalation or broken skin)
Fungal Disease Classifications (5, in order of severity)
- Superficial
- Cutaneous (ringworm)
- Subcutaneous
- Systemic (occur in a normal, immunocompetent host)
- Opportunistic (fungal meningitis)
Opportunistic molds are sensitive to:
neutrophils
Antibodies can prevent:
reinfection by fungi
Three ways fungal infections are diagnosed
- clinical appearance
- microscopic
all but chitin gone after trx with KOH
hyphae present - Culture
yeast yield bacteria like colonies
Sabourauds Medium (high glu, low pH)
Why does fungal culture medium need to inhibit bacteria?
Yeast grow in bacteria-like cultures
What causes the majority of the damage in a fungal infection?
Host immune response
