Archaea

Domain Archaea

• prokaryotes

• membrane chemistry = lipids have ether linkages, different lipid structure

• info processing machinery similar to eukaryotes (polymerases, histones, etc.)

• methanogens, extreme halophiles, or hyperthermophiles

euryarchaeota

• class example: Methanogens

  • methanogenesis = produce methane using H2 + CO2, distic to archaea

  • strictly anaerobes

  • in wetlands, rice paddies, geothermal systems, animal digestive tracts, etc.

  • McrA = key component of enzyme system for methanogenesis

• class example: halophilic archaea

  • adapted to high salt environments

  • extreme halophiles when they like very salty environments

  • may use light driven proton pump (bacteriorhodopsin)

• class example: hyperthermophilic

  • high temperature environments

  • have adaptations to stabilize proteins, DNA, membranes at high temps (ex.: reverse gyrase to keep positive supercoiling)

  • Thermococcus (no cell wall) + Pyrococcus

• class example: Thermoplasma

  • lacks cell wall

thermoproteota/crenarchaeota

• adapted to hot + chemically extreme environments

• many are thermophiles/hyperthermophiles

thaumarchaeota

• important in ammonia oxidation

• major participants in nitrogen cycle

• ecologically important in soil and ocean

asgard archaea

• show relationship to eukaryote origins

• genome studies reveal similarities to eukaryotes

• Lokiarchaeota = most similar to Eukarya

DPANN

• group or several archaeal lineages

• have small genomes/reduced genomes

• some associated with other cells, may depend on partner organisms