adherence and colonisation Flashcards
pili vs afimbrial adhesins
pili - repeating subunit (pilus) with a tip protein, encoded alongside a secretion system
afimbrial: does not share repeating subunit and tip structure
What are the G- pili
chaperone-usher
Type IV pili
What are the g+ types of pili
sortase mediated
type IV pili
chaperone-usher pili
g-, pili
SEC pathway into periplasm
Chaperoned to usher protein which pushes subunits out from the cell
Pilus = FimA subunits
FimH = tip
Type IV pili
found in g+, cyanobacteria, g-
assembly by T2SS
Sortase mediated M1 pili
g+, pili
enzymatic process where the subunits (Spy0128)
are covalently linked together by class C sortase
driven into the cell wall peptidoglycan by sortase A
trimeric autotransporter adhesions
g-, afimbrial
three copies of a protein that forms a trimer
different domains for head, stalk, and anchor
secreted by T5SS
huge variations sequence variation between species type
MSCRAMMs
has a flexible stalk with two motifs that mediate adhesion - protected
undergoes confirmational change when it binds to ligand (protection moves) to bind to receptor
cell wall linked by sortase A
g+ afimbrial adhesin
MSCRAMMs
g- afimbrial adhesin
TAAs
ETEC adherence
adheres to cells independently
20 different fimbrial types, e.g. CFAI
Enteroaggregative E.coli
bind together and to cell
aggregative adherence fimbriae
UPEC
Usher-chaperone pili’s
1. fim-mannose specificity (bladder) FimH
2. Pap - digalactoside specificity (kidney)
EPEC A/E
indication that they’re in intestine
loose adherence with bfp
LEE pathogenicity island
(both events activated by PerA)
T3SS injects Tir
Intimin binds Tir for intimate attachment
actin polymerisation = pedestal formation
What bacteria has a very diverse range of adhesins
M. catarrhalis
