week 11

• Mycology


  The study of fungi. The disease caused by fungi is called MYCOSES
• Fungi


  • Eukaryotic, spore-bearing, heterotrophic organisms that produce extracellular enzymes and absorb their nutrients
  • Cell walls contain chitin for rigidity and support
  • Cytoplasmic membrane contains ergosterols
• General information about fungi

  • Cells are encased within a rigid cell wall, mostly composed of chitin and glucan
  • Heterotrophic, lacking chlorophyll and cannot make their organic food as plants can, through photosynthesis
  • Simpler in structure than plants or animals, no division of cells into organs or tissues

  
• Phylum Zygomycota


  • Sexual reproduction by conjugation, forming zygospores
  • Asexual reproduction involves sporangiospores in a sporangium
  • Typically saprotrophs, parasites, or pathogens of animals, plants, or other fungi

  
• Zygomycota


  • Bread molds, Mucor, Rhizopus
• Mucor


  • Filamentous fungus found in soil, plants, and decaying fruits
  • Causes zygomycosis (mucormycosis) infections

  
• Phylum Microsporidia


  • Ubiquitous spore-forming unicellular parasites, reclassified as fungi
  • Have a long polar filament and a polar cap that serves as a means of extrusion

  
• Phylum Ascomycota


  • Also called "sac fungi" because their sexual spores, ascospores, are produced in a sac-like ascus
  • Asexual spores are usually conidiospores, formed in long chains at the end of conidiophore

  
• Ascomycota


  • Saccharomyces (yeasts used in brewing and bread making)
  • Aspergillus (produces citric acid)
  • Penicillium (produces penicillin, used in cheese making)
  • Neurospora (used in genetic studies)
• Histoplasmosis


  • Infection caused by the fungus Histoplasma
  • Fungus lives in soil with bird or bat droppings
  • Symptoms include fever, cough, fatigue, chills, headache, chest pain, body aches

  
• Candida


  Albicans can be identified with germ tube or colorimetric tests, and selective chromogenic agar media

  
• Candidiasis


  • Fungal infection caused by the yeast Candida, most commonly Candida albicans
  • Can cause infections in the mouth, throat, and vagina
• Vaginal yeast infection


  • Also called vaginal candidiasis, vulvovaginal candidiasis, or candida vaginitis
  • Symptoms include vaginal itching or soreness, pain during sex, pain or discomfort when urinating, abnormal discharge
• Phylum Basidiomycota


  • Commonly called "club fungi" because of the club-shape of the basidium that bears the sexual spores (basidiospores)
  • Includes rusts, smuts, mushrooms, toadstools, puffballs, bracket fungi, and fungi that form associations with roots

  
• When fungal infections should be considered:

  
• Useful properties of fungi

  • Source of food: mushroom
  • Fermentation: production of alcohol, bread, cheese (Saccharomyces)
  • Antibiotic production (penicillin)
  • Ergot from Claviceps purpurea: used to induce uterine contractions
  • Vaccines for Hepatitis B: Saccharomyces cervisiae