Mycology 410: Lecture 4

  1. Triggers for fungal dimorphism
    Temperature, Chemical signals
  2. Pseudohyphae
    Enlongated yeast cells that resemble hyphae
  3. Thermally dimorphic fungi
    • Coccidioides immitis = coccidioidomycosis
    • Paracoccidioides brasiliensis =
    • paracoccidioidomycosis
    • Blastomyces dermatitidis= blastomycosis
    • Histoplasma capsulatum= histoplasmosis
    • Penicillium marneffei = penicillosis
    • Sporothrix schenckii = sporotrichosis
  4. Thermodimorphic fungi will be in what state at body temperature
  5. Pathogenic fungi are ____
    mostly related
  6. Non-pathogenic dimorphic fungi
    • Aureobasidium pullulans = soil and leaf (phylloplane) fungus.
    • Ustilago maydis = maize pathogen
    • Mucor circinelloides = an emerging opportunistic pathogen in immunocompromised patients.  Used in biotechnology for production of beta-carotene
  7. Pathogenic dimorphic fungi enter the body by:
    being uptake in spore form, spores are made from hyphae
  8. Yeast can divide in what ways
    • Fission yeast: transverse septation (equal division of cytoplasm)
    •          -Schizosaccharomyces pombe
    •          -Penicillium marneffei
    • Budding yeast: daughter cell arises from mother cell (more common, unequal division of cytoplasm)
    •          -Saccharomyces cerevisiae
    •          -Cryptococcus neoformans
  9. Mold:
    • Vegetative growing morphology: filamentous hyphae/mycelia
    • Grow apical extension/occasional branching
  10. Mold spreads by:
    Spores, produced by nonreplicating asexual conidia (effective aerosol dispersal)
  11. Mold spores:
    • Arise mitotically, are different than sexual spores
    • Resemble yeast
  12. Processes by which mold change stages
    • Sporulation: developmental process by which hyphae become conidia
    • Germination: Process by which conidia become vegetative growing hyphae
  13. Intermediary forms of dimorphic fungi
    • Germ Tube: Hyphal extension off yeast cell
    • Pseudohyphae: split cells do not separate, but stay attached and elongate, resemble hyphae but lack straight walls and have subtle indentations between the connected cells
  14. Dimorphic shift
    • environmentally regulated
    • involves huge biochemical, metabolic and physiological changes
    • shows non-pathogenic and host-adapted pathogenic morphotype 
    • essential for pathogenesis
Card Set
Mycology 410: Lecture 4
Mycology 410