Archaea Microbiology: Extremophiles

Archaea Microbiology

Extremophiles

• Definition: Organisms that thrive in extreme environments with conditions such as high temperatures, high salinity, high pressure, and high acidity.
• Examples of archaeal extremophiles:
  • Thermococci: thrive in temperatures above 80°C
  • Halophiles: thrive in high salt environments (e.g. salt lakes, salt mines)
  • Piezophiles: thrive in high-pressure environments (e.g. deep-sea vents)
  • Acidophiles: thrive in acidic environments (e.g. hot springs, acidic mines)

Methanogenesis

• Definition: The process of producing methane as a byproduct of metabolism
• Methanogenic archaea:
  • Found in anaerobic environments (e.g. swamps, marshes, digestive systems)
  • Use CO2 as their final electron acceptor in the electron transport chain
  • Produce methane as a byproduct of energy production
  • Examples: Methanococcus, Methanobacterium

Archaeal Membranes

• Composition: Unique lipids with ether linkages instead of ester linkages
• Characteristics:
  • More stable and resistant to extreme temperatures and pH
  • Allow for the maintenance of membrane structure and function in extreme environments
  • Differ from bacterial membranes in their composition and function

Characteristics of Archaea

• Prokaryotic cells
• Lack of peptidoglycan (cell wall component)
• Unique membrane lipids
• Ability to thrive in extreme environments
• Genetic distinctness from bacteria and eukarya

Cell Wall Structures

• Lack of peptidoglycan (cell wall component) *Presence of pseudopeptidoglycan (similar to peptidoglycan but with different sugar molecules)
• S-layer: a protein layer that provides structural support and protection
• Glycoproteins: carbohydrate-modified proteins that provide additional structural support

Archaea Microbiology

Extremophiles

• Thrive in extreme environments with conditions such as high temperatures, high salinity, high pressure, and high acidity.
• Examples include:
  • Thermococci, which thrive in temperatures above 80°C.
  • Halophiles, which thrive in high salt environments (e.g.salt lakes, salt mines).
  • Piezophiles, which thrive in high-pressure environments (e.g.deep-sea vents).
  • Acidophiles, which thrive in acidic environments (e.g.hot springs, acidic mines).

Methanogenesis

• Process of producing methane as a byproduct of metabolism.
• Occurs in anaerobic environments (e.g.swamps, marshes, digestive systems).
• Methanogenic archaea use CO2 as their final electron acceptor in the electron transport chain.
• Produce methane as a byproduct of energy production.
• Examples include Methanococcus and Methanobacterium.

Archaeal Membranes

• Composed of unique lipids with ether linkages instead of ester linkages.
• More stable and resistant to extreme temperatures and pH.
• Allow for the maintenance of membrane structure and function in extreme environments.
• Differ from bacterial membranes in their composition and function.

Characteristics of Archaea

• Prokaryotic cells.
• Lack peptidoglycan (cell wall component).
• Have unique membrane lipids.
• Ability to thrive in extreme environments.
• Genetically distinct from bacteria and eukarya.

Cell Wall Structures

• Lack peptidoglycan (cell wall component).
• Contain pseudopeptidoglycan (similar to peptidoglycan but with different sugar molecules).
• Have an S-layer, a protein layer that provides structural support and protection.
• Contain glycoproteins, carbohydrate-modified proteins that provide additional structural support.

Learn about archaeal extremophiles that thrive in extreme environments such as high temperatures, high salinity, high pressure, and high acidity. Examples of thermococci, halophiles, piezophiles, and acidophiles are included.