Eukaryotes

• Microbial Eukaryotes


  • Algae
  • Protozoa
  • Fungi
• It has been estimated that 50% of the world's population is infected with some type of eukaryotic pathogen
• Microbial kingdoms


  • Fungi
  • Protista
• Protista divisions


  • Algae (plant-like)
  • Protozoa (animal-like)

  
• Mycology


  Study of fungi
• Common characteristics of fungi

  • Chemoheterotrophs
  • Many are decomposers and saprophytes
  • Most are obligate aerobes or facultative anaerobes
  • Few are human pathogens
  • Live as unicellular yeast and multicellular molds

  
• Hyphae


  Long filaments of cells joined end to end
• Types of hyphae


  • Septate hyphae (joined cells have distinct separations)
  • Coenocytic hyphae (hyphae consists of fused cells)
• Mycelium


  A mass of hyphae
• Types of mycelium


  • Vegetative mycelium (grow flat along surfaces to absorb nutrients)
  • Aerial mycelium (stick up off the mycelium to produce spores for reproduction)

  
• Yeasts


  Nonfilamentous, unicellular, oval fungi that reproduce via budding
• Dimorphic fungi


  The same organism can look different when grown at different temperatures (mold-like in colder temps, yeast-like in warmer temps)

  
• Mnemonic: Mold in the Cold and Yeast in the Heat (MCYH)
• Haploid


  Half the number of chromosomes
• Diploid


  A full set of chromosomes
• Fungal phyla


  • Zygomycota (fusion of haploid cells produces a zygospore)
  • Ascomycota (spores formed in a sac)
  • Basidiomycota (spores formed externally on a pedestal)

  
• Rust diseases are caused by a Basidiomycota
• Ergot poisoning by Claviceps (an Ascomycota) may have caused the Salem Witch Trials and Phytophthora infestans caused Irish potato famine
• Cordyceps


  Important insect pathogen (Ascomycota)
• Anamorphs


  Fungi that have lost the ability to reproduce sexually
• How fungi differ from bacteria

  • Grow in acidic environments (pH 5)
  • Resistant to osmotic pressure
  • Grow in low moisture

  
• Lichens


  Combination of green algae and fungus in a mutualistic relationship
• The good of fungi

  • Recycle vital nutrients (compost)
  • Aid plant growth
  • Food and beverage production
  • Vaccine production
  • Drug production
  • Biological control of pests
  • Air quality testing
  • pH indicators

  
• The bad of fungi

  • Food spoilage
  • Crop death
  • Human pathogens
  • Nosocomial infections
  • Respiratory illness
• Mycosis


  Fungal infection
• Types of fungal infections

  • Superficial (cutaneous)
  • Systemic (blood, organs)
• Keratinase


  Enzyme that degrades keratin in hair and skin
• Fungal human pathogens


  • Trichophyton is the organism that causes… tinea capitis, tinea pedis, tinea cruris, tinea corpus
  • Candida albicans (can infect mucus membranes and cause vaginal infections, deadly to AIDS patients)

  
• Opportunistic pathogens


  Generally harmless in normal habitat, become pathogenic in compromised host
• Cryptococcus neoformans is the most common life threatening fungal infection among AIDS patients
• Protista


  Second main microbial phyla, catch-all for organisms that don't fit in other categories
• Protista divisions


  • Phaeophyta (brown algae)
  • Rhodophyta (red algae)
  • Chlorophyta (green algae)
  • Diatoms
  • Dinoflagellates
• Phaeophyta


  Brown algae (kelp), have chlorophyll a and c, xanthophylls, cellulose + alginic acid cell walls, harvested for algin

  
• Rhodophyta


  Red algae, have chlorophyll a and d, phycobiliproteins, cellulose cell walls, produce agar

  
• Chlorophyta


  Green algae, have cellulose cell walls, chlorophyll a and b, store starch polymer
• Domoic acid


  Potent neurotoxin produced by diatoms, can cause domoic acid intoxication in shellfish leading to diarrhea, memory loss, and aggression
• Dinoflagellates


  Unicellular, flagellated, have cellulose walls of interlocked plates
• Green algae (Chlorophyta)


  • Cellulose cell walls
  • Chlorophyll a and b
  • Stores carbohydrate polymer
  • Flagellated or filamentous
  • Unicellular or multicellular
  • Ancestors gave rise to plants
  • Food storage as starch
• Green algae


  • Chlorophyta
• Starch


  • Pondscum