Quorum sensing Flashcards
What is quorum sensing ?
cell-cell signalling to coord expression of virulence in density related process
What are the names the two QS genes?
I and R
What does the I gene do?
encode autoinducer (AIs) synthase, can cross CM
What does the R gene do?
encodes transcriptional activator protein
What causes AI to bind to the transcriptional activator ?
increase in AI concentration (due to high concentration of cells) to the threshold
What do rhamnolipids do?
prevent successful polymorph attack by causing rapid lysis of polymorphs
How is the rhamnolipid and PMN interaction measured experimentally ?
leakage of PMN measured by lactate dehydrogenase
What does Dynorphin do?
induces QS in PA and rhamnolipids
What is the structure of Dynorphin?
endogenous K-agonist belonging to opioid peptides
What are the two QS regulators in PA?
master regulator and workhorse regulator
What is the AI2 precursor?
DPD
What is LuxS?
enzyme involved in AI2
What is LuxP?
regulatory system of AI2
What are diffusible signal factors ?
AI of biofilm dispersal
interspecie signalling
cis-unsaturated fatty acids
What disperses a PA biofilm?
CDA
What disperses a Burkholderia biofilm?
BDSF
What disperses a Burkholderia biofilm?
BDSF
What does diketopiperazine do?
inhibit QS
are secondary metabolites consisting of cyclic dipeptides
inhibit cell synthase (AI)
What does AgrC do?
encodes AI peptide membrane sensor
What does ArgD do?
precursor of AIP
What does ArgB do?
transmembrane protein secreting AIP
What does ArgA do?
response regulator phosphorylated by ArgC
What does a decrease in nitric oxide do?
decreases c-di-GMP = turn off biofilm traits = dispersal
What does pqs do?
contribute to gene regulation independent of its ability to activate pqsR and induce iron starvation response
