Transcript Bacteria - Eubacteria

Archaea
Domain Prokarya/Archaea
Kingdom Archaea
Discovery of Archaea
• Prior to 1977 they were considered bacteria
• 1977 Carl Woese and George Fox proposed
a new domain/kingdom
• 1990 16S rRNA and 18S rRNA sequences
justify separation
• 2003 genome sequence analysis justifies
kingdom/domain status
Lumpers
Shifting
Kingdoms
Plantae Monera Archaea
Splitters
2
3
5
6
8
Bacteria
Bacteria
Bacteria
Bacteria
Bacteria
Archaebacteria
Archaebacteria
Archaebacteria
Archaebacteria
Archaebacteria
Archezoans
Archezoans
Archezoans
Archezoans
Archezoans
Euglenoids
Euglenoids
Euglenoids
Euglenoids
Euglenoids
Chrysophytes
Chrysophytes
Chrysophytes
Chrysophytes
Chrysophytes
Green Algae
Green Algae
Green Algae
Green Algae
Green Algae
Brown Algae
Brown Algae
Brown Algae
Brown Algae
Brown Algae
Red algae
Red algae
Red algae
Red algae
Red algae
Slime Molds
Slime Molds
Slime Molds
Slime Molds
Slime Molds
True Fungi
True Fungi
True Fungi
True Fungi
True Fungi
Bryophytes
Bryophytes
Bryophytes
Bryophytes
Bryophytes
Tracheophytes
Tracheophytes
Tracheophytes
Tracheophytes
Tracheophytes
Protozoans
Protozoans
Protozoans
Protozoans
Protozoans
Myxozoans
Myxozoans
Myxozoans
Myxozoans
Myxozoans
Multicellular
Animals
Multicellular
Animals
Multicellular
Animals
Multicellular
Animals
Multicellular
Animals
Extant
How Many Kingdoms?
8
5
3
Extinct
2
1
The prokaryotes are a?
Original Cell
Grade!
Archaea
• Ancient origin, but appreciated more recently
• Somewhat more advanced than Bacteria
• Extremophiles-90°C pH2 25M anaerobic -4°C Antarctica!
– Methanogens
– Halophytes
– Sulfur metabolism
• DNA binding proteins (but not histones)
• Unicellular, colonial, filamentous
• Bacillus, coccus, spirillum, plate-like, etc.
• Size: 0.1 to 15 µm diam. x 200 µm long
Archaea
Cladogram
Extant
Genera
ThermoThermoplasmales
Thermoproteales
Igneococcales
coccales
Halobacteriales
SulfoloMethanogenales
Archaeoglobales
hales
Halophilic
Chemoheterotroph
resp O2
Chemoautotroph
Light->bacteriorhodopsin->ATP
S+org->H2S+CO2
Hydrothermal vents
MethanogenR lactate->H2+CO2
Autotroph H2+SO4-2->H2S
Methanogens-anaerobes Euarchaeota
CO2+H2->F420 fluorescent ->CH4
Ruminant gut flora
Marshes, landfills
to Bacteria
Original Cell
Crenarchaeota
to Eukarya
Thermophilic
Acidophilic
Autotrophic (CO2)
Sulfur + H2 -> H2S + H+
-O2 Heterotrophic (CH2O)
Sulfur+CH2O->CO2+H2S
+O2 Heterotrophic (TCAR)
Sulfur + O2 -> H2SO4
Prokaryotic Growth
• Cells are generally very small
• Cells may double in size but only before binary
fission
• Growth mostly in terms of cell number or colony
size, etc.
• Doubling time in cell numbers may be 20 minutes
in ideal conditions
• Could quickly take over the earth if conditions
could remain ideal
• Very competitive in ideal environments
• Ultimate survivors - 3.5 billion years!
Cell Structure: Boundary
Thermoplasma
cytosol
Gram Positive
Methanobacterium
cell membrane bilayer
phosphoglycerohydrocarbon, etc.
sulfo- or glyco-glycerohydrocarbon
(ether link not ester link)
transport proteins
regulates input/output
Gram Negative
Thermoproteus
cell wall-glycan
(no muramic acid)
prevents bursting
turgor pressure
thin
surface layer
glycoprotein
releases dye
Homeostasis - metabolism
Facultative and Obligate Anaerobes and Aerobes
Nutrition Mode
Energy Source
Carbon Source
Photoautotroph
Light
CO2
Chemoautotroph
Inorganic chem
CO2
Photoheterotroph
Light
Organic chem
Chemoheterotroph
Organic chem
Organic chem
Chemoautotroph acetyl-CoA or reverse TCA to fix CO2
Photoautotroph Calvin Cycle (Methanococcus, Pyrococcus)
Chemoheterotroph citric acid cycle, fermentation
Sulfur transporters used to drive ATP synthesis
How do Archaea tolerate the heat?
• Proteins stabilized by more ionic bridges between amino acid r-groups
and more-hydrophobic core amino acids
• Heat shock protein (chaperonins) refold denatured
proteins…Pyrococcus 121°C for 1 hour!
• DNA depurination reduced by presence of 2,3-diphosphoglycerate.
• DNA supercoiling by reverse gyrase reduces denaturation
• Sac7d in Sulfobolus is a minor groove protein increases the melting
temperature by 40°C
• Histone-like proteins help stabilize DNA as well
• Heat-resistant di-bi-phytanyl diether lipid membranes (monolayer)
prevent delamination of membrane
Cell Membrane Structure
Composed of diglycerides
R group may be phosphate, sulfate, or sugar
Long chain branched hydrocarbon (not fatty acid)
Hydrocarbons may be C20 or C40
If C20, the membrane is a bilayer:
O
O
O
O
R
R
If C40, the membrane is a monolayer
O
O
O
O
R
R
In some species, the membrane is a mixture of both C20 and C40
diglycerides forming a mixed mono-/bi-layer