Ch 17: Archaeal Diversity (Bio 286 - Microbiology)

Question 1

archaea morphology

Answer 1

prokaryotic cells; look very much like bacteria but can be oddly shaped as well

Question 2

archaeal traits/diversity

Answer 2

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

Question 3

2 major phyla of archaea

Answer 3

Crenarchaeotes, Euryarchaeotes

Question 4

nucleoid

Answer 4

where DNA in an archaea is found

Question 5

introns

Answer 5

found within both eukaryotes and archaea

Question 6

archaeal lipids

Answer 6

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

Question 7

thermophile lipids

Answer 7

tetra-ether lipids; lipid MONOLAYER (prevents melting)

Question 8

archaeal genomes - similarities to bacteria

Answer 8

circular genome; has operons

Question 9

archaeal genomes - similarities to eukaryotes

Answer 9

has introns (noncoding DNA); RNA polymerase has TBP and TFB; has proteins similar to histones

Question 10

archaea cell wall is made of

Answer 10

pseudopeptidoglycan (NOT peptidoglycan)

Question 11

archaea cell wall

Answer 11

pseudopeptidoglycan; disaccharide (NAG and NAT) (not NAM); different chemical linkage; resistant to lysozyme; peptide chain present

Question 12

all living cells have

Answer 12

ribosomes

Question 13

Crenarchaeota

Answer 13

often irregular in shape; always have unique lipid CRENARCHAEOL (tetraether lipid)

Question 14

Crenarchaeota living at high temperatures

Answer 14

often found in hot springs; provide reduced minerals; often very acidic and often ANAEROBIC

Question 15

upper temperature limit for microbial life

Answer 15

140-150 degrees Celsius

Question 16

adaptations to life at higher temperature

Answer 16

tetraether lipids; positive DNA supercoiling; high intracellular solute concentration

Question 17

(adaptation to life at higher temperature) stability of monomers

Answer 17

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)

Question 18

(adaptation to life at higher temperature) structural features that improve thermostability

Answer 18

HIGHLY HYDROPHOBIC CORES; INCREASED IONIC INTERACTIONS on protein surfaces

Question 19

(adaptation to life at higher temperature) protein folding

Answer 19

chaperones - a class of proteins that refold partially denatured proteins

Question 20

chaperones

Answer 20

class of proteins that REFOLD partially denatured proteins

Question 21

thermosome

Answer 21

major chaperonin protein complex in Pyrodictium

Question 22

(adaptation to life at higher temperature) DNA stability

Answer 22

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

Question 23

(adaptation to life at higher temperature) lipid stability

Answer 23

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)

Question 24

desulfurococcales

Answer 24

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

Question 25

sulfolobales

Answer 25

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)

Question 26

sulfolobales can grow

Answer 26

chemoorganotrophically

Question 27

Crenarchaeota living at mesophilic temperatures

Answer 27

(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

Question 28

Crenarchaeota – nitrosopumibiles

Answer 28

OXIDIZE AMMONIA and FIX CO2; found in the ocean but also common in soil

Question 29

Crenarchaeota living at psychiophilic temperatures

Answer 29

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)

Question 30

euryarchaeota includes

Answer 30

methanogens, halophiles, thermococcales, archaeoglobales

Question 31

methanogenesis

Answer 31

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)

Question 32

methanogens

Answer 32

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

Question 33

methanotrophs

Answer 33

consume methane

Question 34

methanogen niches

Answer 34

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)

Question 35

halophiles

Answer 35

“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

Question 36

bacteriorhodopsin and halorhodopsin

Answer 36

both increase proton motive force and use the proton gradient to pump out Na+

Question 37

phototaxis

Answer 37

movement towards light

Question 38

thermococcales

Answer 38

mostly ANAEROBES; use sulfur as electron acceptor; many genes similar to eukaryotes

Question 39

archaeoglobales

Answer 39

reduces sulfate to sulfide; oxidize acetate to CO2 – OPPOSITE OF METHANOGENESIS

Question 40

korarcheota

Answer 40

secret filament

Question 41

thaumarchaeota

Answer 41

nitrification

Question 42

nanoarchaeota

Answer 42

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

Question 43

retinal

Answer 43

(in prokaryotes) is part of light driven ATP synthesis and phototaxis