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25 Cards in this Set
- Front
- Back
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Euryarchaeota
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methanogens and a variety of extremophiles
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Crenarchaeota
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hyperthermophiles
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Euryarchaeota
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-extermely halophilic; >1.5 M of NaCl
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Marine Salterns
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A “bloom” of halophilic Archaea; red color is caused by the pigments of Halobacterium (bacterioruberins
and bacteriorhodopsins) |
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Halobacterium Spp
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-high internal K+ conc.
-cell wall integrity depends on high Na+ conc -contains glycoproteins rich in acidic amino acids -cytoplasmic proteins:high proportion of charged amino acids; K+ requires for ribosome stability |
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Light Driven ATP Synthesis in Halobacterium
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-O2 is depleted
-bacteriorhodopsin is made and inserted into membrane -retinal absorbs light at 570 nm; converts trans-->cis, releasing H+ to outer membrane -when retinal returns to trans, cytoplasmic H+ is consumed; membrane is energized, driving ATP synthesis |
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Methanogenesis
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Obligate anaerobes that use CO2 as a terminal electron
acceptor and produce CH4 |
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Methanogens
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-cell wall: pseudopeptidoglycan, methanochondroitin, glycoproteins, S layer
-metabolically: e- acceptors-CO2 or simple organic molecule -env: mostly mesophilic; but hyperthermophiles, psychrophiles, acidophiles, and halophiles known |
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Methanogenic Substrates (3 Types)
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-CO2 type: CO2, formate, CO
-methylated substrates: methanol, methylamine, -acetotrophic (acetate-like substrate): acetate, pyruvate |
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Thermoplasma and Ferroplasma
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lack cell walls
-tetraether lipoglycan in membranes |
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Nanoarchaeum
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smallest organism (0.4 u) with the smallest genome (0.49 Mb)
-can only grow as a parasite of ignicoccus -genome lacks genes that encode for the biosynthesis of amino and nucleic acids |
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Solfataras
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heated industrial effluents
-deep sea hydrothermal vents |
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Sulfolobus and Acidianus
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hot and sulfur-rich terrestrial springs
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Acidianus
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-a facultative anaerobe
-interesting redox-dependent So utilization |
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Sulfolobus
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-hyperthermophilic acidophile
-aerobic chemolithoautotroph and chemoorganotroph |
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Deep Sea Vents
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-emit hot water that is highly enriched with reduced compounds
-diverse and rich communities live in proximity to the vent; life in absence of light -most extreme hyperthermophilic microbes are found here |
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Pyrodictium
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disc shaped cells that grow a
“mycellium”- like matrix with a role in attachment to crystals of So, its electron acceptor, (energy source: either H2 chemolitho-or an organotrophs) |
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Ignicoccus
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unique for its outer membrane and a "large periplasmic space" (like gram NEG bacteria)
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Crenarchaeota
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ether-linked lipids
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Upper Temperature Limit of Life
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-stability of macromolecules
-140-150 deg C |
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Reverse DNA Gyrase
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-prevents denaturing of DNA
-only found among hyperthermophiles |
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DNA Binding Proteins
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-Sac7d in sulfolobus: incr melting temp by 10 deg C
-histone-like proteins in Euryarchaeota |
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What Makes a Thermophile a Thermophile
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-membrane stability: presence of dibiphenyl tetraether; mono- rather than bi-layer membranes
-16S rRNA gene: high GC content |
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High GC content
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has 3 H bonds, as opposed to 2, making DNA stronger
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Aquifex
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-at > 95 deg C; only Archaea
-highest heat tolerance among the Bacteria |
