Unit 1--Lecture 4 (Archaeal Diversity) Flashcards
2 Major Phyla
Crenarchaeotes and Euryarchaeotes
Thermophile Lipids
Lipid monolayer
Archaeal Genomes
Similarities to bacteria
-circular genome
-has operons
Similarities to eukaryotes
-has introns
-has proteins similar to histones
Archaea Cell Wall
Pseudopeptidoglycan
NAT not NAM
Crenarcheota
Often irregular in shape
Have unique lipid
-Crenarchaeol
Many live at very high temps
-hot springs
Upper Temperature Limit for Microbial Life
140-150 C
Adaptations to Life at High Temperature
Stability of monomers
-protective effect of high concentrations of cytoplasmic solutes
-use of more heat-stable molecules
Protein folding and thermostability
-structural features improve thermostability
–highly hydrophobic cores
–increased ionic interactions
Chaperones (class of proteins that refold partially denatured proteins)
-thermosome
DNA stability
-high intracellular solute levels
-positive supercoils
-high intracellular levels of polyamines
-histones
Lipid stability
-tetraether type lipids
-SSU rRNA stability
–higher GC content
Desulfurococcales
No cell wall
Reduce sulfur at high temperatures
Sulfolobales
Oxidize sulfur at high temperatures
No cell wall
Crenarchaeota
Nitrosopumilales
-oxidize ammonia, fix CO2
Found in ice and seawater in Antartica
Euryarchaeota: Methanogens
5 major orders
-thermophiles, mesophiles found in all orders
-diverse cell forms
Euryarchaeota: Halophiles
Most are photoheterotrophs
Rhodopsins capture light energy
-bacteriorhodopsin pumps out H+
-halorhodopsin pumps in Cl-
-other rhodopsins signal to flagellum
–phototaxis
Euryarchaeota
Archaeoglobales
-reduce sulfate to sulfide
-oxidize acetate to CO2
–opposite of methanogenesis
Emerging Euryarchaeota
Korarchaeota
-secret filament
Thaumarchaeota
-nitrification
Nanoarchaeota
-hospitable fireball
