Extremophiles

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Extremophiles

• David Albright
• Spring 2004

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What are Extremophiles?

• Microorganisms that can survive and even thrive
  in conditions considered to be extreme by human
  standards.
• Extreme conditions
• High or low temperatures
• High or low pH
• High salinity
• High Pressure
• Other desiccation, radiation, high metal conc.,
  etc.

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Objectives

• Identification of types of extremophiles and
  their indigenous environments
• Effects of extremophiles on science
• Evolutional theories
• Search for life outside of Earth
• Enzymes for industrial purposes

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Evolutionary Lineages

• Traditionally thought to be 2
• Bacteria (prokaryotes)
• Eukarya
• Carl R. Woese concludes third Archaea
• Archaea Bacteria common ancestor
• Eukarya later broke from Archaea
• 3 main groups of Archaea grow in extreme
  conditions, possibly similar to those of early
  Earth

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Three Evolutionary Lineages
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Astrobiology and Extremophiles

• Requirements for life ???
• Some conditions on Earth analogous to those in
  space
• Lake Vostok Antarctica
• Europa a moon of Jupiters
• Extremophiles allow for better understanding of
  how and where life may exist in other parts of
  universe

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Conditions in Space
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Extreme Enzymes

• Enzymes biological catalysts
• Extremozymes
• Allow extremophiles to survive in harsh
  environments
• These proteins do not denature in extremes
• Appealing to Industry
• Work in conditions in which normal enzymes would
  fail
• Allow for increased efficiency and new
  applications

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Current / Potential Applications
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Thermophiles / Hyperthermophiles

• Heat-loving
• Best studied of extremophiles
• 60-80 degrees C Thermophiles
• gt80 degrees C Hyperthermophiles
• Found in hot springs and deep-sea thermal vents
• Enzymes do not denature at high T

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Thermophiles / Hyperthermophiles

• Thermus aquaticus
• First discovered thermophile 1969 (hot springs
  Yellowstone Natl Park)
• Later used to fully automate PCR (polymerase
  chain reaction) Taq polymerase replaced
  ordinary enzyme

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Psychrophiles

• Able to survive in sub-freezing temperatures
• Oceans
• Known to grow in sea ice
• Riddled with small holes and channels containing
  very salty water

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Psychrophiles

• Lake Vostok
• About 2 miles below ice cap of Antarctica
• Untouched for thousands of years
• Similar conditions to those on Europa (one of
  Jupiters moons)
• Researchers trying to find way to obtain samples
  without contaminating

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Temperature Limits of Organisms
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Halophiles

• Thrive in high saline concentrations
• Counter forces of osmotic pressure by maintaining
  high salt concentrations in cells (as much as 4-5
  M)
• Natural salt lakes
• Solar salt works

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Halophiles

• Solar salt works
• Manmade or altered brine pools
• Utilize solar energy and wind to evaporate water
• Halophiles commonly produce red carotenoid
  pigments when they bloom
• Defense mechanisms against radiation and UV light
• Causes more heat to be retained, thus higher
  evaporation rates

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Acidophiles

• Can tolerate extremely low pH
• Inside of cell is actually neutral
• Extracellular proteins protect organism
• Enzymes operate below pH of 1
• Hydrothermal vents, acidic hot springs, acid mine
  drainage (sulfurous compounds common)

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Acidophilic Enzymes

• Catalysts for rxns in acidic solutions
• Additives for animal feed
• Improve digestibility of feed
• Break down cheap grains
• Avoid need for more expensive food

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Alkaliphiles

• Thrive in high pH (gt9)
• Inside of cell is actually neutral
• Extracellular proteins protect organism
• Carbonate-rich soils, soda lakes, salt lakes

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Alkaliphilic Enzymes

• Detergent additive
• Normal proteases (protein degraders) and lipases
  (grease degraders) not stable in high alkaline
  conditions
• Perform under wide range of temperatures
  (bacteria live in lakes of various temperatures)

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pH Limits of Organisms
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Piezophiles (a.k.a. Barophiles)

• Pressure Loving
• High pressures restrict biological reactions
• Most chemical rxns result in volume increase
• Located in deep ocean waters
• Known environments contain normal organisms as
  well
• Pressures not high enough to exclude them

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Polyextremophiles

• Extreme environments often contain more than one
  harsh condition
• Extremozymes they produce encompass broader range
  of applications
• Halo-alkaliphiles salt lakes
• Barophiles-psychrophiles deep ocean
• Thermophilic acidophiles hot springs, deep-sea
  thermal vents

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Misc. Extremophiles

• Metallophiles high metal concentrations
• Radiophiles high levels of radiation
• Microaerophiles oxygen deprivation
• Xerophiles - desiccation

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Classifications and Examples
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Conclusions

• Extremophiles have potential to serve broad range
  of applications
• Clues for theories of evolution
• Aid in search for life in space
• New and more efficient industrial applications
• By studying genetic blueprints and gene transfer
  into other microorganisms, genetic and
  biochemical engineers hope to learn how to mass
  produce tough enzymes for use in industry