PRE LAB 2 QUORUM SENSING Flashcards
She is the proponent of quorum sensing
Bonnie Bassler
Her study focus on (1)
Molecular mechanism of the bacteria used for (2)
(1) cell-to-cell communication of bacteria
(2) Intercellular communication
Their goal is to understand how bacteria _______________
How the integration and processing of this information results in the precise ________ within the species involved
detect multiple environmental cues
regulation of gene expression
how bacteria communicate with one another?
secretion of signaling molecules - autoinducers or ligands resulting in regulation of gene expression and change of behavior or physiological processes
In quorum sensing bacteria assess the
population density by detecting the
________ of particular
autoinducers.
concentration
In quorum sensing, it can be observed
the _____________
strength in number
Explain the sensory information flow of lux genes
- signal/autoinducer binds to the membrane-boun receptor
- attraction of RNA polymerase
- induce transcription, translation and production of protein
- create bioluminescence
two types of communication
intercellular - across different species
intracellular - two members of the same kin
Autoinducer varies depending on its
size, polarity and peptide base molecule
example of hydrophobic autoinducer
AHL- Acyl-homoserine lactone
what happens to autoinducer at low and high density
low- diffuse away from the cell
high- bind to receptors, regulate transcription of gene, gene produce autoinducers — positive feedback loop
T or F
Free living V. fischeri can produce their own luciferase
false - only those attached to a host can produce bioluminescence
Quorum sensing determines whether
the bacteria should produce __________
once they are attached to the host
How?
luciferase
if it sense that the host is threatened cell-to-cell comm occurs to trigger its production
coding sequence that encodes the by-product of proteins
Lux operon
lux operon is consists of two proteins
LuxI - produces autoinducer
LuxR - transcriptional activator triggered by AI to recruit the RNA polymerase to transcribe
the reaction between LuxI and LuxR is called
positive inducible regulation
what happens to the lux genes at high density of AI
RNA Polymerase transcribe operons (LuxA and LuxB) with the LuxI and LuxCDABE
the operon that is responsible for light emission is _____ to produce ____
LuxA and Lux B
luciferase
what happens if bacterial concentration is low
transcriptionof the operon will be low, levels of LuxI will be low too
When autoinducers are now ________, it
will trigger the transcriptional
activators, where RNA polymerase is
present, and then transcription will
begin
abundant
