Module 3: Archaea (Phylogenetics) Flashcards
What are the two principle phyla of archaea?
Crenarchaeota and Euryarchaeota
What are the superphyla of archaea?
1) DPANN
2) Euryarchaeota
3) TACK
4) Asgard
What phyla make up DPANN?
1) Diapherotrites
2) Parvarchaeota
3) Aenigmarchaeota
4) Nanoarchaeota
5) Nanohaloarchaeota
6) Woesearchaeota
(DPANN + W = acronym for the phyla!)
What phyla make up TACK?
1) Thaumarchaeota
2) Aigarchaeota
3) Crenarchaeota
4) Korarchaeota
(TACK is an acronym!)
What phyla make up Asgard?
Think “HOLT”
1) Hemiarchaeota
2) Ordinarchaeota
3) Lokiarchaeota (Like marvel Loki)
4) Thorarchaeota (Like marvel Thor)
(To remember: the marvel superphyla!)
What are the two main groups within the euryarchaeota?
1) Methanogens
2) Halophiles
Euryarchaeota
A superphylum of archaea that CANNOT be defined by any single characterisitc!
Methanogens
Archaeons that produce METHANE (CH4)
What is the difference between how methanogens and halophiles are defined?
Methanogens = defined by a shared metabolic process
Halophiles = defined by a shared environmental necessity
What is the reaction that methanogens can carry out?
Reduction of CO2!
CO2 + 4H2 —-> CH4 + 2H2O + ENERGY
Methanogens use energy from CO2 reduction to _____________ which makes them _____________
Methanogens use energy from CO2 reduction to drive carbon fixation which makes them autotrophs
Methanogens are ______________ and therefore must live in ___________ environments
1) Strict anaerobes
2) ANOXIC environs.
Where are methanogens commonly found?
1) Animal digestive tract
2) Sediments of swamps, lakes, salt marshes, oceans, hot springs
What archaea are found in the human GI tract?
Methanobrevibacter smithii
What does M.smithii use to produce methane?
Uses formate and H2 (products of bacterial fermentaiton) to produce methane
How does M.smithii help fermenting bacteria within the human gut?
Utilizes and therefore removes the H2 byproduct of bacterial fermentation
==> Allows for more efficient fermentation (as high levels of hydrogen can be inhibitory to fermenting bacteria!)
Other than the GI tract, where are methanogens found in humans?
The oral cavity!
(Methanobacterium oralis)
–> Found its presence to be correlated to gingivitis and periodontitis
Most methanogens are one of the following (temperature conditions):
Most methanogens are one of the following:
1) Hyperthermophiles
2) Thermophiles
3) Psychrophiles
What is the morphology of methanogens?
Most commonly rod shaped or cocci
What are halophiles?
Archaeons that require high SALT concentrations for growth
(>1.5M NaCl)
In general, what salt concentration is needed for halophiles?
All of them only grow in conditions with > or = to 1.5M NaCl
Where are halophiles found? (3)
1) Great Salt Lake
2) The Dead Sea
3) Arctic hypersaline lakes
What is the salt content of the Great Salt Lake and the Dead Sea?
Great Salt Lake = ~5-25% salinity
Dead Sea = as high as 34% salinity
–> So salty there are no macroscopic forms of life living in these areas!
(Ocean = 3.5% salinity = 0.6M)
What adaptation do halophiles possess which allow them to live in such high saline conditions?
What problems does this adaptation cause?
Maintain a high intracellular potassium concentration (provides osmotic balance to prevent cell shrinkage!)
Problems:
1) Proteins denaturation
2) DNA denaturation