Fungal Basics

Fungal Arrangements
  • Overview:
    • Fungi can proliferate as either single cells or arrange themselves into a multi-cellular structures. Some organisms can only exist in the single-cell form whereas "Dimorphic" fungi can interchange between both single and multi-cellular forms depending on environmental cues.
  • Yeast Form
    • Yeast refers to the single-cell form of fungi where they appear roughly spherical. Division of yeast is often asymmetric with one large and one small daughter cell termed the "bud". In some yeast the buds do not detach from the larger daughter cell and produce a structure termed a "pseudohyphae".
  • Mold Form
    • Mold refers to the multi-cellular form of fungi which appear as branching, tubules termed "Hyphae" that possess septae between individual cells. A mass of enmeshed hyphae is termed a "mold" or "mycelium". Fungal molds can produce "Spores" which are released into the environment and can germinate into actively-growing organisms once deposited in favorable environmental conditions.
Fungal Anatomy
  • Overview
    • Because fungi are eukaryotic they possess internal membrane-bound organelles analogous to those found in eurkaryotic cells such as nuclei, mitochondria, etc. However, fungi do possess a few key differences compared to mammalian cells that can be targeted for therapeutics, are important for disease pathogenesis, or can be used for detection of the organisms.
  • Fungal Cell Membrane
    • The fungal cell membrane is similar to the mammalian plasma membrane and directly contains the fungal cytoplasm. Importantly, the fungal cell membrane requires the presence of a sterol known as "Ergosterol" for proper functioning; in contrast, mammalian membranes use the sterol cholesterol). Ergosterol and the molecular machinery for its synthesis is a key component of antifungal therapeutic strategies.
  • Fungal Cell Wall
    • Many fungi possess carbohydrate-rich cell walls which can induce potent inflammatory responses in hosts. Furthermore, immunity to many fungi is mediated by antibodies to cell wall antigens.
  • Capsule
    • A few fungi possess polysaccharide capsules which can be visualized with special stains.