Lecture 7: Pili/fimbriae and Endospores Flashcards
Tuesday 22nd October
where are type 1 fimbriae widespread in?
Enterobacteriaceae, including most E. coli
Which pathogens is type 1 fimbriae an important virulence factor in?
E. coli
Salmonella spp.
Vibrio cholerae
What is the size of type 1 fimbriae?
7 nm wide and approximately 1-2 µm long surface polymer
What is type 1 fimbriae made up of?
The bulk of type 1 fimbriae is made up of 500-3000 subunits of the protein, FimA, stacked in a helical cylinder
What is the tip adhesin of type 1 fimbriae?
FimH
What does the FimH tip adhesin bind to?
to D-mannose containing structures (we have mannose in many of our cells)
What links FimH adhesin onto type 1 fimbriae?
FimF and FimG
What proteins are associated with the building of type 1 fimbriae itself?
FimC and FimD
What does FimA do?
It hepls build the pili from the base to the top
What proteins catalyse FimA polymerisation?
FimC and FimD
What is another name for P pili?
PAP: Pyelonephritis-Associated-Pili
What is P-pili a critical virulence factor for?
Critical virulence factor of uropathogenic E. coli (UPEC) which cause cystitis and pyelonephritis
Does cystisis cause discomfort, but not a lot of damage?
Yes
Describe pyelonephritis
- Pyelonephritis is a UTI that reaches the kidneys
- Can be fatal
How is P-pili similar to type 1 fimbriae?
Similar in structure and assembly
What is the tip adhesin of P-pili?
PapG, which binds to surface globoside receptors (glycolipid) in uroepithelial cells
What are the 3 variants of PapG?
PapG1, PapG2 and PapG3
Which bacteria is type IV pili most common in?
Gram negatives
Give some examples of gram negative bacteria
- Enterobacteriaceae
- Salmonella enterica
- Pseudomonas aeruginosa
- Legionella pneumophila
- Neisseria gonorrhoeae
- Neisseria meningitidis
- Vibrio cholerae
- some cyanobacteria
can type VI pili be gram positive?
Some can, but they’re mostly gram negative
Give an example of a gram positive type VI pili
Clostridia
Is it true that Type VI pili are typically longer than fimbriae?
Yes (up to 10 µm)
Is it true that there’s only few pili per cell with type VI pili?
Yes (on the order of 1-10)
Are type VI pili typically at both poles of the cell?
Yes