T1iii: Outline the classification of fungi

Definition

Fungi – group of eukaryotic microorganisms capable of producing infection

Fungal Structure

Cell Membrane

  • Bilayered cell membrane
  • Contains sterols → Ergestrol being the essential sterol of fungi
  • Amphoterecin B and Nystatin bind to ergosterol and punch holes in the fungal cell membrane
  • Ketoconazole inhibits ergosterol synthesis
Fungal Cell

Cell Wall

    • CHO & Proteins surrounding cell membrane

Capsule

  • Polysaccharide coating around cell wall
  • Visualized with India Ink Stain

Microtubules

    • Microtubules composed of the protein tubulin
    • Involved in movement of organelles, chromosomes, nuclei and golgi vesicles

Morphology

Yeasts

    • Unicellular, reproduce by budding
    • C albicans

Molds

  • Characterized by hyphae which result in colony formation
  • Aspergillus

Dimorphism

    • Have charateristics of yeast and mould
    • Blastomyces dermatitidis, Histoplasma

Pathogenic Fungi

Cuteanous Infective Agents

    • Fungus grows on body surface
    • Tinea pedis, vaginal candidiasis

Subcutaneous Infective Agents

  • Nails and deeper layers of skin involved
  • Mycetoma, sporotrichosis

Systemic Infective Agents

    • Involvement of internal organs
    • Histoplasmosis, systemic candidiasis