• Extremely halophilic Archaea require large
amounts of NaCl for growth.
• These organisms accumulate large levels of KCl in
their cytoplasm as a compatible solute. These salts
affect cell wall stability and enzyme activity.
• The light-mediated proton pump bacteriorhodopsin
helps extreme halophiles make ATP.
Thermoplasmatales
Thermococcales
Methanopyrales
Methano-bacteriales
-coccales
-microbiales
-sarcinales
Archaeoglobales
Extreme Halophiles
Haloalkaliphiles
Marine Euryarcheota
Sulfolobales
Thermoproteales
Pyrodictiales
Desulfurococcales
Marine Crenarcheota
Methanogens
• Microbes that produce CH4
– Found in many diverse environments
– Taxonomy based on phenotypic and
phylogenetic features
– Process of methanogensis first
demonstrated over 200 years ago by
Alessandro Volta
Methanogenesis
• The biological production of CH4 from either CO2
plus H2 or from methylated organic compounds.
• A variety of unique coenzymes are involved in
methanogenesis
• The process is strictly anaerobic.
• Energy conservation in methanogenesis involves
both proton and sodium ion gradients.
• Diversity of Methanogens
– Demonstrate diversity of cell wall
chemistries
• Pseudomurein (e.g., Methanobacterium)
• Methanochondroitin (e.g.,
Methanosarcina)
• Protein or glycoprotein (e.g.,
Methanocaldococcus)
• S-layers (e.g., Methanospirillium)
• Substrates for Methanogens
– Obligate anaerobes
– 11 substrates, divided into 3 classes, can be
converted to CH4 by pure cultures of
methanogens
• Other compounds (e.g., glucose) can be
converted to methane, but only in
cooperative reactions between
methanogens and other anaerobic
bacteria
Methanogenesis
1 – Methanofuran: CO2
activation
2 – Methanopterin:
CO2
CHO
methyl
3 – COM
CHO
CH3
4 – COM + COB + F430
methylreductase
5 – CH3 Methane
• Although hyperthermophiles live at very high
temperatures, in some cases above the boiling
point of water, there are temperature limits beyond
which no living organism can survive.
• This limit is likely 140–150°C. Hydrogen (H2)
catabolism may have been the first energy-yielding
metabolism of cells.
Evloluntionary
history of
chloroplasts via
endosymbiosis:
The
Symbiont
1
2
3
Origin of the palstids: Cyanobacteria (Bacteria, Prokaryotes)
Recipients: Various algae (Protists, Eukaryotes):
1. Glaucophyta
2. Cryptomonads
3. Rhodophyta
4. Chlorophyta
5. Euglenophyta
6. Chlorachniophyta
7. Chrysophyta
8. Heterocontae
9. Diatoms
10. Dinoflagellata (green)
11. Dinoflagellata (brown)