L3-Quorum Sensing Flashcards
Where are AHL’s found?
Gram negative bacteria
As population increases what happens to the concentration of AHL?
increases
What transcriptional regulator does AHL bind to?
LuxR
What does LuxR induce?
Transcription of LuxI
What are AIP’s?
auto-inducing peptides
What are AIP’s secreted by?
gram-positive bacteria
How do AIP”s trigger signalling?
via a two-component system
What is a biofilm?
an aggregate of bacterial cells attached to a surface and encased in an adhesive matrix that is secreted by the cells
What percentage of infections are biofilms responsible for?
up to 80%
What is the function of proteases?
break down proteins to provide a carbon source for growth
What is the function of haemolysins?
lyse blood cells, releasing a source of iron for bacteria
What does the LuxI protein encode?
AHL’s (AHL Synthase)
What is AIP initially produced as?
propetide- needs to be processed before being actively secreted
What happens once external threshold concentration of AHL is reached?
diffuses back into cell and binds to LuxR
What is a gram negative bacteria that is commonly found in soil and water, and is also the dominant pathogen found in CF patients?
Pseudomonas aeruginosa
