Fungi Morphology and Reproduction

• Fungi are morphologically divided into mushrooms, yeasts, and molds.
• Some fungi can grow as either yeasts or molds depending on the temperature, and these are known as dimorphic fungi.
• Dimorphic fungi grow as yeasts in tissues at 37° C and as molds in natural environments and labs at 25° C.
• Fungi can grow in the presence or absence of oxygen.
• Fungi can be multicellular (hyphae) or unicellular organisms.
• Hyphae with cross walls (septa) are called septate hyphae.
• Hyphae with no septa are called coenocytic hyphae.
• Fungi reproduce asexually (budding) or sexually (genetic recombination).
• Lichens consist of hyphae and cyanobacteria or green algae.

Asexual Spores

• Sporangiospores are spores inside a sac called a sporangium.
• Conidia (condiospores) are spores not enclosed by a sac.

Types of Conidia

• Arthrospore: rectangular spore.
• Chlamydospore: spherical spore.
• Blastospore: buds from a parent cell.
• Phialospore: buds from the mouth of a vase-shaped cell.
• Microconidium and macroconidium: spores formed by the same fungus under different conditions; one cell (micro), two or more (macro).
• Porospore: grows out through small pores.

Pathogenic Fungi

• Superficial Mycoses (Cutaneous Mycoses) affect the surface of the body.

Dermatomycoses

• Also known as Tinea or ringworm.

• Trichophyton affects hair, skin, and nails.

• Epidermophyton affects skin and nails.

• Microsporum affects hair and skin.

  • Tinea capitis: Ringworm of the scalp.
  • Tinea corporis: Ringworm of the body.
  • Tinea cruris: Jock itch.
  • Tinea unguium: Ringworm of the nails.
  • Tinea pedis: Athlete's foot.
  • Tinea versicolor: A fungal infection that causes small, discolored patches of skin.

• Sporotrichosis is caused by Sporothrix schenckii.

• Candidiasis is caused by Candida albicans.

• Candidiasis may result from suppression of immunity.

  • It can affect the genitourinary tract (vaginal yeast infection).
  • It can cause diaper rash in infants.
  • It can cause mouth infection (oral thrush).

Deep Mycoses

• Examples include:
  • Aspergillus
  • Candida
  • Blastomyces
  • Histoplasma
  • Cryptococcus
  • Coccidioides
  • Paracoccidioides

Algae

• Algae are photosynthetic, aquatic organisms.
• Algae reproduce asexually and sexually.

Classification of Algae

• Chlorophyta: green algae.
• Rhodophyta: red algae (cell wall contains agar).
• Phaeophyta: brown algae.
• Chrysophyta: golden & yellow-green algae & diatoms; cell wall contains silica.
• Diatoms are the major source of the world’s oxygen.

Protozoans

• Eukaryotes, unicellular, and lack a cell wall.
• Mostly motile.
• Require a moist environment to survive.
  • Trophozoite: motile active, feeding form.
  • Cyst: dormant form (unfavorable environment).
• Protozoans reproduce asexually through schizogony where the nucleus undergoes multiple divisions before the cell divides.