4B. Microbial Diversity - Archaea

Question 1

Eukarchaeota (phylum)

Answer 1

extreme halophiles

Question 2

Haloarchaea (genus) - phylum, old name, example, location, pH

Answer 2

• PHYLUM: euryarchaeota
• OLD: halobacteria
  ex) halobacterium salinarum
• needs high salt concentration
• 9% of NaCl for growth (can’t even grow in mannitol salt cuz it’s only 7.5%)
• LOCATION: solar salt evaporation ponds and salt lakes
• pH: alkaliphiles because these ponds and lakes are high in alkaline

Question 3

adaptations for haloarchaea (genus)

Answer 3

• needed for highly ionic environments
• usually achieved by accumulation or synthesis of compatible solutes
• pumps large amounts of K+ into the cell from the environment
• intracellular K+ concentration exceeds extracellular Na+ concentration
• water flows into the cell in hypersaline environments

Question 4

Energy system in haloarchaea (genus)

Answer 4

• light driven synthesis of ATP without the use of chlorophylls
  they use a pigment instead (bacteriorhodopsin):
• integral membrane protein
• absorbs light energy and pumps protons across the membrane to make a PMF
• PMF used to generate ATP
• do not fix CO2 therefore photoheterotrophy (gets energy from light and pre-existing carbon)

Question 5

Methanogenic archaea (genus) - phylum, oxygen, energy, defining features

Answer 5

• PHYLUM: euryarchaeota
• ENERGY: chemolithoautotrops
• OXYGEN: strict anaerobes (cows gut, sewage sludge)
• only microbes capable of significant methane production
• produce the bulk CH4 in the atmosphere - GHG

Question 6

Cell wall in methanogenic archaea (genus)

Answer 6

• pseudomurein
• methanobacterium - only they have this
• most other types of methanogens have S-layer made of protein or glycoprotein as their cell wall

Question 7

thaumarchaeota (genus) - defining features, example, oxygen, energy, location

Answer 7

• accomplishes nitrification
• converts NH3 into NO2 for energy
• uses CO2 for carbon
  ex) nitrosopumilus maritimus
  OXYGEN: aerobic
  ENERGY: ammonia oxidizing chemolithoautotroph (gets energy from inorganic chemicals)
  LOCATION: abundant in open ocean water

Question 8

nanoarchaeota (phylum) - example, defining features

Answer 8

nanoarchaeum equitans
- smallest cellular organism
- obligate parasite 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 it’s cellular needs

Question 9

korarchaeota (phylum): example, oxygen, energy, location, defining features

Answer 9

Korarchaeum cryptofilum
- OXYGEN: obligately anaerobic
- ENERGY: chemoorganotroph
- LOCATION: - depends on other members of hot springs community
- still can’t be grown in pure culture
- hyperthermophile
- cells are long, thin filaments
- lack many core genes

Question 10

crenarchaeota (phylum): energy, defining features

Answer 10

ENERGY: chemoorganotrophs or chemolithotrophs - most use sulfur in their metabolism
- most are hyperthermophiles (hot springs, deep ocean vents
- other representatives are found in extremely cold environments

Question 11

crenarchaeota (phylum): example, oxygen, energy, defining features

Answer 11

sulfolobus acidocaldarius grows in sulfur-rich acidic hot springs
- hyperthermophile and acidophile
- OXYGEN: aerobic
- ENERGY: chemolithotroph (inorganic chemicals for energy) that oxidizes reduces sulfur or iron

Question 12

asgard superphylum of archaea

Answer 12

• only known from sequence of metagenomes
• version of genes previously thought to be euk-specific
• first time cultured in a lab in 2020
• 10 years to isolate and grow
• syntrophic growth: will only grow in the presence of another bacteria
• amorphus
• leads to hypothetical eukaryogenesis theory