Microbial Ecology

• Microorganism = Bacteria, Archaea, Eukaryotes
• Microbe = Bacteria, Archaea, Eukaryotes, and Virus
• Are all microorganisms microbes?

  yes
• Are all microbes microorganisms?

  no
• What are the 4 most common bacterial shapes?

  Spherical (coccus), Rod (bacillus), Curved Rod (vibrio), Spiral (spirillum)
• external stresses to bacteria can cause morphological changes
• after division bacteria usually stay together, such as in chains or clusters
• do bacteria have a nucleus?

  no
• some cyanobacteria such as Synechococcus contain carboxysomes
• What are carboxysomes?

  protein encased structures containing enzymes involved in the photosynthetic transformation of CO2 into organic material
• do archaea have a nucleus?

  no
• do eukarya have a nucleus?

  yes
• archaea are similar in size, chromosomes and organization to bacteria
• most archaea appear to be spherical or rod-shaped
• archaea are single-celled organisms
• bacteria have ester linkages (less stable) while archaea have ether linkages (more stable) which allow them to live in more extreme environments
• archaea are more similar to eukaryotes
• archaea are more structurally similar to bacteria
• archaea are more transcriptionally similar to eukaryotes
• Eukaryote = true nucleus
• eukaryotes are typically larger than bacteria and archae
• Giardia duodenalis

  • causes diarrhea
  • flagellated
  • parasitic
• Balantidium coli

  • causes diarrhea
  • parasitic
  • ciliate
  • pig origin/zoonotic disease
• Saccharomyces cerevisiae

  • yeast
  • single celled fungi
  • important in winemaking, baking (bakers yeast), and brewing
• Fuligo septica

  • slime mold
  • "scrambled egg slime"
  • world wide
  • found on black mulch mostly
  • appears after heavy rain or excessive watering
  • antibiotic properties
  • resistance to toxic levels of metals
• What are the three primary producers?

  coccolithophores, diatoms, green algae
• coccolithophores

  • increases ocean albedo
  • C cycling
  • O2 production
  • algal blooms
• green algae

  • model organism for understanding the function of eukaryal flagella
  • O2 production
• Eukaryotes have diverse roles and functions
• Viruses rely on their host
• Viruses

  • small
  • replicate in living host cells
  • obligate intracellular parasites
  • have RNA or DNA genome
  • some have a viral envelope
• What is a viral envelope?

  are made by lipids that are taken from the host membrane when infected
• Viruses play roles in:

  • disease
  • evolution
  • biogeochemistry
• viruses can be used in biotechnology and health related research
• bacteriophages can also infect archaea
• Mimivirus

  • host is Amoeba
  • enveloped
  • very large genome size
  • ~400 nm diameter
  • codes for 1000s of genes
  • included in important metabolic pathways
  • uses horizontal gene transfer to steal host genes
• Viral Phages

  • infect other viruses
  • they co-infect
• What is Co-Infection of viruses?

  when smaller viruses co-infect they enter the host cell with a larger virus and replicate in its replication factory which ultimately causes the bigger virus to loose replication machinery so it cant replicate
• enviroment - everything surrounding a living organism
• ecosystem -> the physical enviroment with which microbes interact