Fundamental Medical Mycology

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Fundamental Medical Mycology

• Fungal Characteristics
• Fungal Classification
• Fungal Terminology

Some of the images herein are taken from
Kaminskis Fungal Jungle Power Points with some
modifications
www. mycology.adelaide.edu.au/Fungal_Jungle/kamins
ki.html
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Biological Relationships

• Mycology is the study of Fungi. Fungi (singular,
  fungus) are a group of organisms similar to and
  different from animals, plants, protists, and
  bacteria.

Fungi
Protists
Bacteria
Animals
Plants
Multicell v v
v
One cell
v v v
Eukaryote v v v
v
Phototroph v
X v
Autotroph v
X v
Heterotroph v v
v v
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Fungal characteristics

• The fungi grow as molds (moulds), yeast, or
  combinations of the 2 (dimorphism). In that
  latter case they usually grow as mold in the
  environment and as yeast-type cells in vivo.
• Groups of cells grow via filamentous extensions
  called hyphae. Collectively these are known as
  mycelia - especially true of the molds.
• Mold colonies are fuzzy masses of mycelia
  whereas yeast colonies are smooth and homogeneous
  like those of bacteria.
• Yeast are primarily single celled organisms.
• Fungi possess cell walls composed of chitin,
  but are in most other ways similar to other
  Eukaryotes.

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Fungal characteristics

• Fungi generally reproduce both sexually
  asexually via production of tough spores. They
  produce asexual spores called conidia at the
  end of aerial hyphae. Sexual spores vary between
  groups of molds. Yeast utilize a unique asexual
  mechanism called budding.
• All fungi are capable of aerobic heterotrophic
  respiration. Some are also capable of
  fermentation. Nutrients are acquired via simple
  absorption (diffusion).
• Fungi, especially molds, are saprophytes.
  They derive neutrients and energy from dead and
  decaying matter making them critically important
  to Earths nutrient cycle.

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Fungal characteristics

• Fungi inhabit most habitats on planet Earth
  including terrestrial aquatic, but most are
  terrestrial organisms.
• Some fungi coexist in mutualistic relationships
  with plants (ex. Mycorhizae), algae (lichens),
  insects (termites), etc.
• Most parasitic fungi are plant pathogens, indeed
  fungi are responsible for the most ecomonically
  significant plant diseases.
• and then there are some fungi that are human
  pathogens.?

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Fungal characteristics - clinical

• Fungal pathogens are opportunistic infection is
  unlikely in immunocompetent individuals. Normal
  microbiota (mainly bacterial) prevents fungal
  infection in most cases.
• Most human fungal infections are epidermal /
  peripheral. Internal systemic fungal infection
  is limited to immunocompromised individuals for
  the most part.
• Non-specific cell-mediated immunity are the
  primary means of defense vs fungal infection.
• Fungi vary in regard to morphology, sexual
  life-cycles / sexual spores, and the extent of
  infection (see table 19-3). Fungi are classified
  primarily on these 3 bases. ?