• 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.

ThermoplasmatalesThermococcalesMethanopyrales

Methano-bacteriales-coccales-microbiales-sarcinales

Archaeoglobales Extreme Halophiles Haloalkaliphiles Marine Euryarcheota

Sulfolobales ThermoprotealesPyrodictialesDesulfurococcalesMarine 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:

TheSymbiont

1

2

3

Origin of the palstids: Cyanobacteria (Bacteria, Prokaryotes)

Recipients: Various algae (Protists, Eukaryotes):

1. Glaucophyta 2. Cryptomonads 3. Rhodophyta 4. Chlorophyta 5. Euglenophyta6. Chlorachniophyta7. Chrysophyta8. Heterocontae9. Diatoms10. Dinoflagellata (green)11. Dinoflagellata (brown)