PHLecture3 - ARCHAEA 1977 CARL WOESE AT ILLINOIS rRNA...

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ARCHAEA 1977 CARL WOESE AT ILLINOIS rRNA Extremophiles thrive in “hostile” environments -
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thermophiles , live at high temperatures; * hyperthermophile s, live at very high temperatures (present record is 121°C); * psychrophiles , like it cold (one in the Antarctic grows best at 4°C); * halophiles , which live in very saline environments (like the Dead Sea); * acidophiles , live at low pH (as low as pH 1 and die at pH 7!); * alkaliphiles , thrive at a high pH.
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General Characteristics Diversity in: Morphology Reproduction Physiology Ecology The best known archaea grow in anoxic, arctic, hypersaline,hyperthermophilic habitats, but also live marine arctic, temperate and tropical waters
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Morphology May stain gram-negative or gram positive Maybe spherical, rod-shaped, spiral, lobed, cuboidal, Triangular, plate-shaped, irregularly shaped or Pleomorphic Single celled, filament or aggregate
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Characteristics 1. 1/10 size of eucaryotes (few micrometers to 10 mirometers 2. Small genomes G+C content (21 to 68 %) Appear to have few plasmid 3. Has genes like bacteria for transcription, translation and DNA metabolism and core metabolism 4. Has 70S ribosomes (not 80S) 5. Signature rRNA signatures 6. Produce unique cofactors for use in methanogenesis
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Characteristics con’t 7. Resistant to antibacterial antibiotics 8. DNA in ill-defined structure, NUCLEOID 9. None are animal pathogenes
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Characteristics con’t Cell Membrane- contain unique lipids ( isoprenoid groups), linked to glycerol by diether linkages rather than ester linkages. R groups may be sugars, hydrogen or phosphate. Forms are Bilayer -glycerol diether or Monolayer- diglycerols tetraethers Most have no cell wall Some have ridgid cell walls of pseudomurein (gram positive) or polysaccarides- disaccaride units joined by alpha 1,3 linkages and L-amino acids (gram negative)
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Unique Cell Membranes Structure
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Phyllum=singular Euryarchaeota = primarily methanogens, some hyperthermophiles and marine species Crenarchaeota = hyperthermophiles and cold dwelling archaea (psycrophiles) Korarchaeota = hyperthermophiles thought much like
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This note was uploaded on 04/02/2008 for the course MMG 201 taught by Professor Jackson during the Spring '08 term at Michigan State University.

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PHLecture3 - ARCHAEA 1977 CARL WOESE AT ILLINOIS rRNA...

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