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Archaea Domain Prokarya/Archaea Kingdom Archaea. Discovery of Archaea Prior to 1977 they were considered bacteria 1977 Carl Woese and George Fox proposed.

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Presentation on theme: "Archaea Domain Prokarya/Archaea Kingdom Archaea. Discovery of Archaea Prior to 1977 they were considered bacteria 1977 Carl Woese and George Fox proposed."— Presentation transcript:

1 Archaea Domain Prokarya/Archaea Kingdom Archaea

2 Discovery of Archaea Prior to 1977 they were considered bacteria 1977 Carl Woese and George Fox proposed a new domain/kingdom S rRNA and 18S rRNA sequences justify separation 2003 genome sequence analysis justifies kingdom/domain status

3 Shifting Kingdoms Bacteria Archaebacteria Archezoans Euglenoids Chrysophytes Green Algae Brown Algae Red algae Slime Molds True Fungi Bryophytes Tracheophytes Protozoans Myxozoans Multicellular Animals Lumpers SplittersPlantaeMoneraArchaea

4 How Many Kingdoms? Multicellular Animals MyxozoansProtozoans Tracheophytes Bryophytes True Fungi Slime Molds Red algae Brown Algae Green Algae Chrysophytes EuglenoidsArchezoans Archaebacteria Bacteria Original Cell Extant Extinct Long Time with Prokaryotes only The prokaryotes are a?Grade!

5 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

6 Archaea Cladogram Pyrodictium Thermoproteus Halococcus Thermofilum Archaeoglobus Desulfurococcus SulfolobusPyrococcus Methanococcus Methanobacterium Thermoplasma Haloferox Haloarcula Original Cell Extant Genera to Bacteria Igneococcales Pleurophillus Thermococcus Ferroglobus Pyrobaculum Sulfolo- hales Thermoproteales Archaeoglobales Thermo- coccales Thermoplasmales Halobacteriales Methanogenales Euarchaeota Crenarchaeota to Eukarya Thermophilic Acidophilic Autotrophic (CO 2 ) Sulfur + H 2 -> H 2 S + H + -O 2 Heterotrophic (CH 2 O) Sulfur+CH 2 O->CO 2 +H 2 S +O 2 Heterotrophic (TCA R ) Sulfur + O 2 -> H 2 SO 4 Halophilic Chemoheterotroph resp O 2 Chemoautotroph Light->bacteriorhodopsin->ATP Methanogens-anaerobes CO 2 +H 2 ->F 420 fluorescent ->CH 4 Ruminant gut flora Marshes, landfills S+org->H 2 S+CO 2 Hydrothermal vents Methanogen R lactate->H 2 +CO 2 Autotroph H 2 +SO >H 2 S

7 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 billion years!

8 Cell Structure: Boundary Gram Positive Methanobacterium Gram Negative Thermoproteus Thermoplasma cell 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 bursting turgor pressure releases dye

9 Homeostasis - metabolism Chemoautotroph acetyl-CoA or reverse TCA to fix CO 2 Photoautotroph Calvin Cycle (Methanococcus, Pyrococcus) Chemoheterotroph citric acid cycle, fermentation Sulfur transporters used to drive ATP synthesis Nutrition ModeEnergy SourceCarbon Source PhotoautotrophLightCO 2 ChemoautotrophInorganic chemCO 2 PhotoheterotrophLightOrganic chem ChemoheterotrophOrganic chem Facultative and Obligate Anaerobes and Aerobes

10 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

11 Cell Membrane Structure O O O O R R O O O O R R 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: 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


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