Archaea Domain Prokarya/Archaea Kingdom Archaea. Discovery of Archaea Prior to 1977 they were...
-
Upload
erin-jenkins -
Category
Documents
-
view
229 -
download
3
Transcript of Archaea Domain Prokarya/Archaea Kingdom Archaea. Discovery of Archaea Prior to 1977 they were...
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
Shifting Kingdoms2 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
Lumpers SplittersPlantae Monera Archaea
How Many Kingdoms?
Mul
ticell
ular
Animals
Myx
ozoa
ns
Proto
zoan
s
Trache
ophy
tes
Bryop
hytes
True F
ungi
Slime M
olds
Red al
gae
Brown A
lgae
Green A
lgae
Chrys
ophy
tes
Euglen
oids
Archez
oans
Archae
bacte
ria
Bacter
ia
Original Cell
Extant
Extinct
Long Time with
Prokaryotes only
8
5
3
2
1
The prokaryotes are a? 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
Pyrod
ictiu
m
Thermop
roteu
s
Haloc
occu
s
Thermof
ilum
Archae
oglo
bus
Desulfu
roco
ccus
Sulfolo
bus
Pyroc
occu
s
Meth
anoc
occu
s
Meth
anob
acter
ium
Thermop
lasm
a
Halof
erox
Haloa
rcula
Original Cell
ExtantGenera
to Bacteria
IgneococcalesPleu
roph
illus
Thermoc
occu
s
Ferro
glob
us
Pyrob
aculu
m
Sulfolo-hales
ThermoprotealesArchaeoglobales
Thermo-coccales
ThermoplasmalesHalobacteriales Methanogenales
EuarchaeotaCrenarchaeota
to Eukarya
ThermophilicAcidophilic
Autotrophic (CO2)Sulfur + H2 -> H2S + H+
-O2 Heterotrophic (CH2O)Sulfur+CH2O->CO2+H2S
+O2 Heterotrophic (TCAR)Sulfur + O2 -> H2SO4
HalophilicChemoheterotroph resp O2
ChemoautotrophLight->bacteriorhodopsin->ATP
Methanogens-anaerobesCO2+H2->F420 fluorescent ->CH4
Ruminant gut flora
Marshes, landfills
S+org->H2S+CO2 Hydrothermal ventsMethanogenR lactate->H2+CO2
Autotroph H2+SO4-2->H2S
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
Gram PositiveMethanobacterium
Gram NegativeThermoproteus
Thermoplasmacell membrane bilayer phosphoglycerohydrocarbon, etc. sulfo- or glyco-glycerohydrocarbon (ether link not ester link) transport proteins
cell wall-glycan (no muramic acid)
thin surface layer glycoprotein
cytosol
regulates input/output
prevents burstingturgor pressure
releases dye
Homeostasis - metabolism
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
Nutrition Mode Energy Source Carbon Source
Photoautotroph Light CO2
Chemoautotroph Inorganic chem CO2
Photoheterotroph Light Organic chem
Chemoheterotroph Organic chem Organic chem
Facultative and Obligate Anaerobes and Aerobes
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
O O
O O
R
R
O O
O O
R
R
Composed of diglyceridesR group may be phosphate, sulfate, or sugarLong chain branched hydrocarbon (not fatty acid) Hydrocarbons may be C20 or C40
If C20, the membrane is a bilayer:
If C40, the membrane is a monolayer
In some species, the membrane is a mixture of both C20 and C40 diglycerides forming a mixed mono-/bi-layer