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Extremophiles!

Extremophiles!. Life living in anthropocentrically extreme environments: Temperature pH (Acidity or Alkalinity) Salinity (Osmotic Stress) Radiation Barometric Pressure. Halophilic Archaea. Life in hypersaline habitats.

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Extremophiles!

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  1. Extremophiles! Life living in anthropocentrically extreme environments: Temperature pH (Acidity or Alkalinity) Salinity (Osmotic Stress) Radiation Barometric Pressure

  2. Halophilic Archaea Life in hypersaline habitats. Not just tolerant of high salt but require it for physiological function. Need a minimum of 1.5 M NaCl (or other salt); Live in 2-7 M NaCl; where seawater is 0.7 M NaCl. Alkaliphilic Natronobacteria Mostly Chemoheterotrophs; depend on oxygenic photosynthetic green algea Dunaliella and anoxygenic phtosynthetic purple bacteria Ectothiorhodospira and Halorhodospira. Few are partially photoheterotrophic at low oxygen (need ATP supplement) (Halobacterium salinarum)

  3. Halobacterium Phototrophy See Box20.1 (p 462) Why the purple membrane?

  4. Thermoplasmatales(cell wall-less; extreme acidophiles) • Thermoplasma: • Thermophile as well (likes 55 ºC) • Chemoheterotroph • Ferroplasma: • Chemolithoautotroph; • Autotrophic by oxidizing Fe(II) • Acid mine drainage archaea • Picrophilus: • Most extreme acidophile (0.6 pH optimum)

  5. Hyperthermophiles • Thermococcales (Euryarchaeota): • Anaerobic sulfur reducing chemoheterotroph. • Flagellated motility • Temperature optimum 88-100 ºC • Archaeoglobales (Euryarchaeota): • Anaerobic sulfate reducers • Temperature optimum 83 ºC

  6. Cultured CrenarchaeotaHyperthermophiles Submarine volcanic Acidic terrestrial volcanic Terrestrial volcanic

  7. The unique archaeal morphology of Pyrodictium; disc-like cells with network of intertwined thread-like appendages.

  8. Bacterial “Extremophiles” Thermophilic chemolithoautotroph Thermophilic chemoheterotroph Radiation tolerance 10,000x humans.

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