22. P. aeruginosa Flashcards
P.aeruginosa is a _______________ because it usually infects those with compromised immune system
opportunistic pathogen
What regulates the expression of virulence factors in P.aeruginosa?
quorum sensing (QS) network
CF is caused by mutations in the ____________________, a chloride channel
cystic fibrosis transmembrane conductance regulator (CFTR)
What is alginate? Function?
Mucoid exopolysaccharide that is produced in large amounts in biofilms
Protection from phagocytosis/attenuates host immune response
What do the bacteria in a QS network use to communicate with each other?
Autoinducers - activate/repress QS target genes
Autoinducers are called what 2 things?
AHLs (acyl homoserine lactones)
or
HSLs (homoserine lactones)
Why are QS signals called autoinducers?
They are self-generated extracellular molecules that get transported BACK into the cell when present in high concentrations
QS in P. aeruginosa is comprised of 2 interlinked AHL-dependent regulatory circuits known as? Function?
las, rhI
Control virulence gene expression
3 ways bacteria benefit from establishing biofilms?
- Persist in an infection (protection from antibiotics)
- Resistance to harsh environments
- Resistance to host defenses (inhibit complement activation, inhibit recruitment/phagocytosis)
What controls the expression of the rhI system?
LasR
How do small AHL molecules get across bacterial membranes? What about AHLs with longer acyl chains?
Small - diffuse
Longer acyl chains - active transport via efflux/influx pumps
QS synchronizes gene expression in response to…
cell population density
Biofilms are embedded within a _________________ comprised of _____________
self-produced matrix
comprised of exopolysaccharide alginate
P.aeruginosa is Gram-______, and its motility is via what?
Gram-negative
Single polar flagella
Autoinducer of las system?
2-oxo-C12-HSL
