Ch 17: Archaeal Diversity (Bio 286 - Microbiology) Flashcards
archaea morphology
prokaryotic cells; look very much like bacteria but can be oddly shaped as well
archaeal traits/diversity
widest temperature range: 2-121 degrees Celsius; widest range of environments: pH 0, high pressure, anaerobic; unique biochemistry: methane production (the only biological producers), have pseudopeptidoglycan instead of peptidoglycan, and have differences in glycolytic pathways
2 major phyla of archaea
Crenarchaeotes, Euryarchaeotes
nucleoid
where DNA in an archaea is found
introns
found within both eukaryotes and archaea
archaeal lipids
L-glycerol (not D-glycerol); ETHER links (not ester); branched chains of lipids made from isoprene units with no unsaturation in lipid; can be more exotic forms such as macrocyclic diether or cyclopentane rings
thermophile lipids
tetra-ether lipids; lipid MONOLAYER (prevents melting)
archaeal genomes - similarities to bacteria
circular genome; has operons
archaeal genomes - similarities to eukaryotes
has introns (noncoding DNA); RNA polymerase has TBP and TFB; has proteins similar to histones
archaea cell wall is made of
pseudopeptidoglycan (NOT peptidoglycan)
archaea cell wall
pseudopeptidoglycan; disaccharide (NAG and NAT) (not NAM); different chemical linkage; resistant to lysozyme; peptide chain present
all living cells have
ribosomes
Crenarchaeota
often irregular in shape; always have unique lipid CRENARCHAEOL (tetraether lipid)
Crenarchaeota living at high temperatures
often found in hot springs; provide reduced minerals; often very acidic and often ANAEROBIC
upper temperature limit for microbial life
140-150 degrees Celsius
adaptations to life at higher temperature
tetraether lipids; positive DNA supercoiling; high intracellular solute concentration
(adaptation to life at higher temperature) stability of monomers
protective effect of HIGH CONCENTRATIONS OF CYTOPLASMIC SOLUTES; use of more HEAT STABLE MOLECULES (ex: use of non-heme iron proteins instead of proteins that use NAD and NADH)
(adaptation to life at higher temperature) structural features that improve thermostability
HIGHLY HYDROPHOBIC CORES; INCREASED IONIC INTERACTIONS on protein surfaces
(adaptation to life at higher temperature) protein folding
chaperones - a class of proteins that refold partially denatured proteins
chaperones
class of proteins that REFOLD partially denatured proteins
thermosome
major chaperonin protein complex in Pyrodictium
(adaptation to life at higher temperature) DNA stability
HIGH INTRACELLULAR SOLUTE LEVELS stabilize DNA; reverse DNA gyrase introduces POSITIVE SUPERCOILS into DNA to stabilize DNA; high intracellular levels of POLYAMINES (putrescine, spermidine) (chemically stabilize nucleic acids); HISTONES (DNA binding proteins) compact DNA into nucleosome-like structures
(adaptation to life at higher temperature) lipid stability
posses dibiphytanyl TETRAETHER TYPE LIPIDS (form a lipid monolayer membrane structure); SSU rRNA STABILITY (due to higher GC content, which makes more hydrogen bonds and is thus more stable)
desulfurococcales
no cell wall (but S-layer is present); reduce sulfur at high temperatures; some survive at ocean thermal vents; variable shapes due to lack of cell wall
sulfolobales
oxidize sulfur at high temperatures; produces sulfuric acid (needs both heat and acidity, so is easy to grow in these conditions); no cell wall (but THICK S layer present), attacked by fuselloviruses (proving that archaea can be attacked by viruses too)
sulfolobales can grow
chemoorganotrophically
Crenarchaeota living at mesophilic temperatures
(20 to 40 degrees Celsius, room temperature to fever body temperature); found in high numbers in the oceans but number depends on time of year; also associated with plant roots: nitrosopumibiles
Crenarchaeota – nitrosopumibiles
OXIDIZE AMMONIA and FIX CO2; found in the ocean but also common in soil
Crenarchaeota living at psychiophilic temperatures
found in high numbers in deep ocean; cenarchaeum associated with deep water sponge; FOUND IN ICE AND SEAWATER IN ANTARCTICA (0 degrees Fahrenheit where salt water freezes)
euryarchaeota includes
methanogens, halophiles, thermococcales, archaeoglobales
methanogenesis
coupled with proton motive force formation and ATP synthesis through activity of ATPases; requires ANAEROBIC ENVIRONMENT; H2 is electron donor and CO2 as electron acceptor (creates CH4 - methane - as product); acetate or formate as electron acceptor (creates CO2 and CH4 as product); use membrane Na+ potential; cofactors hold C during process (coenzyme M, methanofuran, cofactor F420)
methanogens
5 MAJOR ORDERS (most are nonhalophilic mesophiles); thermohpiles and mesophiles are found in all orders; diverse cell forms (cocci, short bacilli, long bacilli, irregular); NEED AN ANAEROBIC ENVIRONMENT
methanotrophs
consume methane
methanogen niches
termite hindgut; wet wood of trees; rumen (“bovine flame thrower”, part of the stomach of a cow); protozoa; cecum; black sea/carioca trench/anaerobic oceans; human large intestine; hydrothermal vent; tundras (Taiga); landfills/swampes/marshes/sediments; rice paddies; sewage sludge digester (wastewater treatment center)
halophiles
“salt loving” archaea; largest naturally occurring plasmids; organic molecules raise internal osmolarity; high GC content in DNA prevents denaturation in high salt environment; elongated/round/flattened shapes; most are photoheterotrophs (use light energy to survive); RHODOPSINS capture light energy… BACTERIORHODOPSIN pumps out H+… HALORHODOPSIN pumps in Cl-… other rhodopsins signal to flagellum for phototaxis
bacteriorhodopsin and halorhodopsin
both increase proton motive force and use the proton gradient to pump out Na+
phototaxis
movement towards light
thermococcales
mostly ANAEROBES; use sulfur as electron acceptor; many genes similar to eukaryotes
archaeoglobales
reduces sulfate to sulfide; oxidize acetate to CO2 – OPPOSITE OF METHANOGENESIS
korarcheota
secret filament
thaumarchaeota
nitrification
nanoarchaeota
hospitable fireball; tightly bound together archaea that cannot separate because they are dependent upon each other; laboratory isolation cannot be performed without its counterpart anarchaea
retinal
(in prokaryotes) is part of light driven ATP synthesis and phototaxis
