distinctive characteristics of archaea - smith college · distinctive characteristics of archaea...
TRANSCRIPT
![Page 1: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/1.jpg)
Distinctive characteristics ofArchaea
• Cell wall• Lipids/membrane• Information processing• Physiological adaptations to extreme
environments
![Page 2: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/2.jpg)
Pseudomurein
Fig. 20.2 Substitutes for N-Acetylmuramic acid (NAM) of peptidoglycan
![Page 3: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/3.jpg)
Fig. 20.1
Gram+ vs. Gram- ArchaeaGram+Cell wall of pseudomurein orother complex carbohydrate
Gram-No outer membraneNo cell wallThick protein/glycoprotein coat
![Page 4: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/4.jpg)
Archaeal Lipids
• Fatty acid attached by ethernot ester links
• Varying lengths of carbonside chains- 20 or 40 carbon
Fig. 20.3
![Page 5: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/5.jpg)
Flexible
Rigid-givesmembranestability tothermophiles
Fig. 20.5
![Page 6: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/6.jpg)
ArchaeaSimilarities to prokaryotes• Size• Shape• Lack nucleus• Single chromosome• Genes in operons• No introns
Similarities to eukaryotes• Few plasmids• RNA
polymerase/promoters• Translation machinery:
ribosome and tRNA
Sequencing of Methanococcus jannaschii in 199256% of genes not similar to bacteria or eukaryotes!
![Page 7: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/7.jpg)
Major groups of Archaea
• Methanogenic archaea• Archaeal sulfate reducers• Extremely halophilic archaea• Cell wall-less archaea• Extremely thermophilic S0-metabolizers
![Page 8: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/8.jpg)
Methanogens
• Largest group of Archaea• Form methane (CH4) from CO2 or other
compounds (e.g. formate, methanol, acetate)• Strict anaerobes• Found in a variety of anaerobic environments rich
in organic matter• Causes cows to belch!• Methane: energy source vs. greenhouse gases
![Page 9: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/9.jpg)
Fig. 20.12
![Page 10: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/10.jpg)
Fig. 20.10
![Page 11: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/11.jpg)
Sulfate-reducing archaea
• Only genus is Archaeoglobus• Reduces sulfates to produce
sulfide (H2S)• Extremely thermophilic
(optimum=83˚C)• Strictly anaerobic• Isolated from a deep sea
thermal vent
![Page 12: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/12.jpg)
Extremely thermophilic S0-metabolizers
• Obligately thermophilic(70-110˚C)
• Mainly strict anaerobes• Can be acidophilic• S0 reduce to sulfide• Hot springs of
Yellowstone
![Page 13: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/13.jpg)
Extreme halophiles
• Require high NaCl concentration– Require 1.5 M, optimum 3-4 M
• Primarily aerobic• Carotenoids give reddish color• Bacteriorhodopsins capture light for energy in
anaerobic respiration
![Page 14: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/14.jpg)
![Page 15: Distinctive characteristics of Archaea - Smith College · Distinctive characteristics of Archaea •Cell wall •Lipids/membrane •Information processing •Physiological adaptations](https://reader030.vdocuments.site/reader030/viewer/2022021622/5b78432a7f8b9a47518ece6e/html5/thumbnails/15.jpg)
Cell wall-less archaea
• Thermoplasma and Picrophilaceae• Resistant to antibiotics• Like warm, acidic environments• Thermoplasma isolated from coal refuse piles
– 55-59˚C, pH 1-2• Picrophilaceae can grow at pH=0