Mycology

• Mycology


  Study of fungi
• Mycology includes


  • Mushrooms
  • Molds
  • Yeasts
• Molds


  • Exhibit filamentous type of growth
• Yeasts


  • Exhibit pasty or mucoid form of fungal growth
• There are over 50,000 valid species of fungi
• Fungi


  • Stain gram positive
  • Require oxygen to survive
  • Eukaryotic
  • Heterotrophic
• Two groups of fungi


  • Yeasts
  • Molds
• Yeasts


  • Single-celled organism
  • Reproduce by budding process
• Molds


  • Produce hyphae, a long, hollow, branching filaments
  • Hyphae separate into compartments (septate)
• Dimorphic fungi


  Fungi capable of growing as yeasts at one temperature and as molds at another
• Examples of dimorphic human pathogens


  • Blastomyces dermatidis
  • Histoplasma capsulatum
  • Coccidioides immitis
• Many fungi are useful in medicine and industry
• Mycological research has led to the development of antibiotic drugs such as penicillin, streptomycin, and tetracycline, as well as other drugs, including statins (cholesterol-lowering drugs)
• Yeasts are found in soil and water and on the skins of many fruits and vegetables
• Yeasts have been used for centuries to make wine and beer
• Saccharomyces cerevisiae is a yeast used in baking
• Algae and fungi are used as a source of single-cell protein for animal and human consumption
• The flavor of cheeses like bleu cheese, Roquefort, Camembert, and Limburger are due to molds that grow in them
• Many diseases of crop plants, grains, corn, and potatoes are caused by molds
• Some fungi produce toxins (mycotoxins) that cause disease in humans and animals
• Molds and yeasts also cause a variety of infectious diseases of humans and animals — collectively referred to as mycoses
• Fungi are found virtually everywhere
• Some fungi are harmful, some are beneficial
• Fungi

  Represent a diverse group of eukaryotic organisms that include yeasts, molds, microsporidia, and fleshy fungi (e.g., mushrooms)
• Fungi are the "garbage disposers" of nature
• Fungi are not plants; they are not photosynthetic
• Fungal cell walls contain a polysaccharide called chitin
• Fungi


  • Some are unicellular, while others grow as filaments called hyphae
  • Hyphae intertwine to form a mass called a mycelium
  • Some fungi have septate hyphae (the hyphae are divided into cells by cross walls or septa)
  • Some fungi have aseptate hyphae (the hyphae do not contain septa)
• Fungal reproduction


  Can occur by budding, hyphal extension, or the formation of spores
• Types of fungal spores


  • Sexual spores
  • Asexual spores (also called conidia)
• Some fungi produce both asexual and sexual spores
• Fungal spores are very resistant structures
• Types of fungal infection


  • Superficial/cutaneous - present on skin, hair, nails
  • Subcutaneous - infection in tissues under the skin
  • Systemic - causes disease exclusively in immunocompromised individuals
• Ringworm (Tinea)


  A common skin infection caused by a fungus
• Types of ringworm (Tinea)


  • Tinea Pedis (Athlete's foot)
  • Tinea Unguium (Onychomycosis)
  • Tinea Cruris (Jock itch)
  • Tinea Capitis (Scalp)
  • Tinea Barbae (Beard)
  • Tinea Manuum (Hands)
  • Tinea Corporis (Other parts of the body)
• Malassezia fungi are associated with dandruff and seborrheic dermatitis
• Diagnostic tests for fungal infections


  • Combination of Microscopic and Macroscopic observations
  • Immunodiagnostic procedures, including skin tests
• Antifungal agents such as nystatin and amphotericin B are used to treat fungal infections
• Preventive measures for fungal infections


  • Wear clean shoes and slippers
  • Wash feet, hair, groin and face daily, dry them well
  • Wear clean socks, clothing, towels and underwear
  • Change underwear and socks daily
  • Let sneakers air out and wash them regularly
  • Do not share personal clothing such as towels
  • Take shoes off at home to expose feet to air
• Vaginal yeast infections (Candidiasis)


  A vaginal infection spread by the fungus Candida