MMI 302 Lecture: Ruby 1
Home > Preview
The flashcards below were created by user
on FreezingBlue Flashcards.
Quorum Signaling is an example of
- bacterial cell to cell signaling
- Allows determination of how many bacteria are in vicinity
Minimum number of things needed to take an action
What does Quorum signaling control?
Specific gene activation
- acyl-homoserine lactone
- Common molecule for quorum signaling in proteobacteria
- Made by AHL synthase
- Binds protein receptors to activate gene
Signal levels based on density of bacteria
- Low levels, signals diffuse away
- High levels, no net diffusion, bacteria know that they have friends around
- Free living bacteria (i.e. planktonic bacteria) begin attaching to surface
- More bacteria grow and attach in response to Quorum signalling
- Form extracellular polysaccharide membrane
- Become pillar shape
- When nutrients run out the film degrades and cells re-disperse
Experimental evidence for quorum signalling in virulence
Wild-type and non-QS mutant are inoculated into a mouse. Far less death in non-QS mutant.
AHL/Peptide QS Molecules
- AHL: 5 member 1 O ring with subs, Gram -
- Peptide: Used by Gram +
Peptide signalers are produced, accumulate, activates cascade for gene transcription
What would you like to do?
Home > Flashcards > Print Preview