Lecture 6B - Archaea Flashcards
within it the archaea cell contains cytoplasm and DNA
cell membrane
how does the cell membrane of Archae differ from other cells
- chirality of glycerol
- ether linkage
- isoprenoid chains
- branching of side chains
phospholidpid (glycerol) is the L-stereoisomer
chirality
- lack the protruding O atom in ester linkages
- confers different property
- survive in extremely acidic or basic environments
- survive in extremes in temp.
ether bonding
what does the ether bonding allow regarding the survival of Archaea
- extremely acidic or alkaline envi.
- extremes in temp.
side chains of Archaea
20 carbon atoms built from isoprene
- makes it possible to form transmembrane phospholipids
- can form carbon rings which add stability to CM
branching of side chains
- thermophilic mycoplasma-like archaeon
- evolved a unique cytoplasmic membrane structure
Thermoplasma sp
cytoplasmic membranes of many archaea are structurally a __ __ made up of __ __ __
- lipid bilayer
- glycerol diether lipids
rotating structures with a filament, as seen in bacterial flagella
archaeolla or archaeollum
What is identified in flagellated archaea that is involved in flagellation
single major genetic locus
compared to bacterial flagella, archaeal flagella are more similar to what
bacterial type IV pili
have conserved amino acid sequences at their N termini, both in mature proteins and in their class III signal peptides, which are similar to type IV pilins
flagellins
unique subunit packing of flagella of two phylogenetically distant members of Archaea
lack central channel
(subunits added at base instead of pushed to the tip)
role of archaella
- motility
- chemotaxis
role of archaella in
S. solfataricus
essential for swarming motility
role of archaella in Pyrococcus
cables connecting cells
results in the formation of a structured bispecies biofilm
interaction between
Pyrococcus furiosus &
Methanopyrus kandleri
- hollow tube-like structures appear to connect cells after division
- leading to a dense network composed of numerous cells and tubes
- could serve as a means of anchoring a community of cells to a surface
Cannulae
- long helical tube with three hooks at the far end
- appear to allow cells to attach both to one another and to surfaces, encouraging the formation of a community.
Hami
length and diameter of hamus
1-3 µm (length)
7-8 nm (diameter)
helical base structure, with three prickles
hamus filament
what can be found in the distal end of hamus
tripartite, barbed grappling hook
major protein of pilus
pilin (~17kDa)
