Section 3 Flashcards
differences of archea (4 things)
1- diff phospholipids
2- pseudopeptidoglycan + S Layer rather than peptidoglycan cell wall
3- transcription promotors and RNA pol is more similar to eukaryotic
4- extremophiles
diff of archeal viruses (7 things)
1- encode pesudopeptidoglycan specific lysin enzyme
2- have NO RNA viruses
3- have on ss DNA virus (rest are dsDNA)
4- have circular dsDNA packed in virion
5- many have envelopes
6- released without lysis
7- not pathogens and extremophiles so hard to research
Model Archeal virus:
Sulfolobus spindle-shaped virus (SSV-1)
lemone shaped
SSV-1 virus encodes the enzyme ________
reverse gyrase
Function of SSV-1 reverse gyrase:
introduces positive supercoils into DNA protecting it at higher temperatures (common in hyperthermophiles)
SSV-1 is a temperate virus:
1- integrates into host genome
2- gets induced for replication by UV damage or stress
3- goes through round of replication to make and release visions
4- goes back into lysogenic state
SSV-1 type of DNA and times of transcription:
dsDNA CIRCULAR (takes 6 hours to transcribe late genes)
T-ind (immediate early)
T5 and T6 (early after 1 hr)
T9 (late early 5 hrs)
Late gene after 6 HOURS
Shape of SSV-1 capsid protein
NEVER SEEN BEFORE 1
4- stranded helices (4 strands of protein come together as one cable)
THEN 6 of these cables wrap around outer surface of the virion capsid and tail)
Conserved
Another archaeal virus :
Acidianus two tailed virus (ATV)
also lemon shaped
ATV grow tails (elongate outside of the cell when temperature is above 75 degrees)
NEVER SEEN BEFORE 2
Finishes growth and maturation OUTSIDE host cell
ATV infects at ____ degrees (host optimal growth temp) and integrates into host chromosome
85
if ATV infects at suboptimal temp, it leads to
Viral replication and lysis
Lambda
Good conditions —-> replication and lysis
Bad conditions—–> integrate and wait
V.S
ATV
Good conditions (85 deg) —->
Bad conditions (suboptimal temp) —->
ATV
Good conditions —-> integrate 85 deg
Bad conditions ——-> replicate and lyse
Another archaean virus (#3)
sublolobus islandicus rod-shaped virus
sublolobus islandicus rod-shaped virus structure
helical shaped structures with tails at the end
sublolobus islandicus rod-shaped virus shape UPON infection
NEVER SEEN BEFORE 3
viral protien makes unusual pyramid structure on cell surface which open to make holes (like a gate) that the virus is released through
Another archaean virus (#4)
Acidianus filamentous virus 1 (AFV-1)
AFV-1 structure
NEVER SEEN BEFORE 4
hook structure at the end of visions that claws to attach to host cells plius
Another archaean virus (#5)
Sulfolobus turreted icosahedral virus (STVI)
STVI facts
- tightly packed structure
- high proline content
- increase in electrostatic interactions in capsid proteins
- increased polar surface
evolutionary adaptations
Why do archeal cells get released without lysing cells?
due to cell wall structures having a wide diversity of structures (don’t have rigid peptidoglycan) so can get out by budding they don’t have to lyse
Cytoplasmic membrane
Surface layer (S-layer)
Protein sheath
glycocalyx
lipoglycan
methanochondrotin
peseudomurein
are there RNA archeal viruses
metagenomic evidence from acidic hot springs has isolated nucleic acids and looked for high amounts of RNA and found RdRp enzyme sequences
