Lecture Set 4 : Part 3 Flashcards
how are the archaea split phylogenetically?
-into 5 phyla
-despite a small number of phyla, they have the same extent of diversity as bacteria and eukarya
what are the 5 archaea phyla?
-euryarchaeota
-thaumarchaeota
-nanoarchaeota
-korarchaeota
-crenarchaeota
what is the euryarchaeota phylum?
-extremely halophilic archaea (haloarchae/halobacteria) and methanogenic archaea
what are the characteristics of the extremely halophilic archaea?
-have adaptations to deal with needing to live in highly ionic environments
-some have a unique system for generating energy
what are the characteristics of methanogenic archaea?
-only microbes capable of significant methane production (methanogens)
-strict anaerobes
-found in many diverse anaerobic environments (cows gut or sewage sludge)
-have diverse cell walls (either an S-layer of protein or glycoprotein or a thick polysaccharide cell wall)
what is an example of a methanogenic archaea?
-methanobacterium
-oxidize CO2 into methane and water
-produce the bulk of methane in the atmosphere (important green house gas)
-have a cell wall of pseudomurein
what is pseudomurein?
-peptidoglycan like polymer
-lacks N-acetyl muramic acid
-has L-acetyl-talosaminuronic acid instead
-sugars are linked by beta 1-3 glycosidic bonds instead of beta 1-4 glycosidic bonds
what is the unique system that some haloarchaea have for generating energy?
-light - driven synthesis of ATP without the use of chlorophylls
-use a pigment called bacteriorhodopsin instead (integral membrane protein)
-the pigment absorbs light energy and pumps protons out of the cell where they are rebrought in my ATPase to make a PMF
-the archaea is not fixing CO2 (get their carbon from organic sources so it is not autothrophy) (photoheterotrophy)
what must halophiles do to live in highly ionic environments? what does halobacterium salinarum do specifically?
-must maintain osmotic balance, do so by accumulating or synthesizing compatible solutes
-halobacterium salinarum pumps large amounts of K+ into the cell from the environment
-intracellular K+ > extracellular Na+
-water flows into the cell to keeo turgor pressure even in the hypersaline environment
what is plasmalysis?
-cell shrinking
what is osmotic lysis?
-cell bursting
what is an example of a haloarchaea?
-halobacterium salinarum
-has a square morphology
-has an absolute requirement for high salt concentrations (need at least 1.5M or 9% NaCl to grow)
where is halobacterium salinarum found?
-solar salt evaporation ponds
-salt lakes (salt concentration approaches saturation)
-soda lakes (highly alkaline hypersaline lakes)
-ex: great salt lake (utah), dead sea
what is an example of an archaea within the thaumarchaeota phylum?
-nitrosopumilus maritimus
-aerobic and ammonia oxidizing chemiolithoautotroph
-converts NH3 into NO2- for energu
-uses CO2 for carbon
-abundant in open ocean water (major player in nitrogen cycling)
what is an example of an archaea within the nanoarchaeota phylum?
-nanoarchaeum equitans
-one of the smallest cellular organisms (0.4 micro meters)
-obligate parasite of the crenarchaeote ignicoccus genus (not a pathogen to humans)
-contains one of the smallest known genomes (lacks genes for all but core molecular process)
-doesnt need to hold its own genes if it depends upon a host cell for most of its needs
what is an example of an archaea within the korarchaeota phylum?
-korarchaeum cryptofilum
-obligately anaerobic chemoorganotroph
-hyperthermophile (found in hotsprings)
-cells are long thin filaments
-lacks many core genes (depends on other members of the hot spring community)
-cannot be grown in pure culture
what is the crenarchaeota phylum?
-most are hyperthermophiles and are found in extremely hot environments (boiling hot springs or deep ocean vents)
-some are found in extremely cold environments
-chemoorganotrophs or chemolithotrophs (most use sulfur in their metabolism)
what is an example of an archaea in the crenarchaeota phylum?
-sulfolobus acidocaldarius
-grows in sulfur rich acidic hot springs (90 degrees, pH of 2 = hyperthermophile + acidophile)
-aerobic chemolithotroph that oxidizes reduced sulfur or iron
