Eukaryotic species Flashcards
phylogenetically, archaea are split into ____ phyla
5
Euryarchaeota
- extremely halophilic archaea
- haloarchaea
- key genus: halobacterium
- have a requirement for high salt concentrations
- typically require at least 1.5 (~9%) NaCL for growth
- found in solar salt evaporation ponds and salt lakes where the salt concentration approaches saturation
- found in great salt lake (Utah), dead sea, as well as soda lakes that are highly alkaline hypersaline environments
- posses adaptations to life in highly ionic environments
euryarchaeota: extremly halophilic archaea: water balance
- halophiles need to maintian osmotic balance
- this is usually achieved by accumulation or synthesis of compatible solutes
- halobacterium species instead pump large amounts of K+ into the cell from the environment
- intracellular K+ concentration exceeds extracellular Na+ concentration and positive water balance is maintained
Euryarchaeota: extremely halophilic archaea unique feature
- found in some haloarchaea is light-driven synthesis of ATP using bacteriorhodopsin(reason the cells are pink)
- cytoplasmic membrane proteins that can absorb light energy and pump protons across the membrane to make ATP
- cannot fix CO2
- they are photoheterotrophs
Euryarchaeota: methanogenic archaea
key genera
methanobacterium, methanosarcina
Euryarchaeota: methanogenic archaea why are they termed methanogens
because they are the only microbe capable of significant methane production
-produce the bulk of CH4 in the atmosphere (important green house gas)
Euryarchaeota: methanogenic archaea
- strict anaerobes, found in many diverse anaerobic environments
ex. cows gut; sewage sludge
Euryarchaeota: methanogenic archaea
deomstrate diversity of ______ chemistries
cell wall
- pseudomurein (eg methanobacterium) similar in structure to peptidoglycan (less similar in composition) only the methanobacteriales family has this type of cell wall
- most other types of methanogens have a S-layer made of protein of glycoprotien as their cell wall
Euryarchaeota: methanogenic archaea
substrates for methanogens
- obligate anaerobes that use a very limited rage of substrates: H2 + CO2, formate, acetate, methanol
- ex, members of genus methanobacteium can use H2 + CO2 but not methanol or acetate, members of methanosarcina can use acetate, methanol, but only some use H2+CO2
- other compounds (eg glucose) can be converted to methane, but only in cooperative reactions between methanogens and other anaerobic bacteria)
thaumarchaeota and nitrification in archaea:
key genus
nitrosopumillus
thaumarchaeota growth
grows chemolithotrophically by aerobically oxidizing ammonia
- uses CO2 as its only carbon source
- can grow at very low levels of ammonia
thaumarchaeota is indigenous to …
open ocean water where they are major player in ammonia oxidation
-others are involved in nitrification in soils
Nanoarchaeota
- ex. nanoarchaeum equitans
- one of the smallest cellular organisms (~0;4 um)
- obligate symbiont of the crenarchaeote ignicoccus
- contains one of the smallest genomes known
- lacks genes for all but core molecular processes
- depends upon host for most of its cellular needs
Korarchaeota and the secret filament
- ex. korarchaeum cryptofilum
- obligately anaerobic chemoorganotroph
- hyperthermophile
- cells are long thin filaments
- lacks many core genes
- depends on other members of hot springs community and cannot yet be grown in pure culture
Crenarchaeota
- most are hyperthermophiles
- found in extreme heat environments
- others are found in extreme cold environments
- chemoorganotrophs or chemolithotrophs
- some species can respire aerobically
- some species carry out anaerobic respiration
- NO-3, S^0, Fe3+ as electron acceptors
- H2 electron donor
