Difference between revisions of "Team:Aix-Marseille/QS"

Line 22: Line 22:
 
We tested the effect of this fatty acid on Xanthomonas and Pseudomonas in differents parameters:fatty acid concentration, medium for bacteria, type of tube. The point of theses experiments are to show the effect of this molecule on biofilm production when we add it in medium at different moments of growth. To charaterize the quantity of biofilm, we use purple crystal coloration, that mark on tube a ring of biofilm. Then we mesure with TECAN the quantity of biofilm.
 
We tested the effect of this fatty acid on Xanthomonas and Pseudomonas in differents parameters:fatty acid concentration, medium for bacteria, type of tube. The point of theses experiments are to show the effect of this molecule on biofilm production when we add it in medium at different moments of growth. To charaterize the quantity of biofilm, we use purple crystal coloration, that mark on tube a ring of biofilm. Then we mesure with TECAN the quantity of biofilm.
  
'''Mesure of biofilm density by coloration by purple crystal then sonication'''
 
  
The plaque containing the peignes is used to color the ring of biofilm by purple cristal. After rincing, the ring will be off hook by sonication and the purple cristal resolubilised will be mesured at DO 570nm.
 
 
Protocol
 
 
#Add a drop of CV in each well (pipette). I let colore 10 minutes at 30°C .
 
#Blow the liquide
 
#Rince twice with water MiliQ
 
#Add 250µl physiologic water (0.9% NaCl) + ethanol 60%
 
#Agitation auto during 2 minutes
 
#Mesure OD570nm.
 
  
 
'''Mesure OD600nm plaque bottom TECAN'''  
 
'''Mesure OD600nm plaque bottom TECAN'''  
  
 
[[File:T--Aix-Marseille--plaqueviolettecan.jpeg|thumb|]]
 
[[File:T--Aix-Marseille--plaqueviolettecan.jpeg|thumb|]]
 
 
 
#Take off the cap
 
#Agitation auto during 2 minutes (amplitude 3mm orbitale)
 
#Mesure OD600 above through the plaque (25 flashes).
 
#The OD600 is proportional to biofilm production.
 

Revision as of 16:39, 11 October 2017

Quorum sensing


Quorum Sensing Approach

The quorum sensing is a mechanism involving chemical compounds that create a line of communication for various bacterium which regulate their behavior in the confined of their population. Xylella fastidiosa communicates by quorum sensing to coordinate the biofilm production and bacterial virulence with fatty acids. But, bacteria use a set of instruction called the quorum quenching to blur the quorum sensing of other bacterial population.

Read more…

The Biobricks

According to the paper "Promiscuous Diffusible Signal Factor Production and Responsiveness of the Xylella fastidiosa Rpf System" and “The Putative Enoyl-Coenzyme A Hydratase DspI Is Required for Production of the Pseudomonas aeruginosa Biofilm Dispersion Autoinducer cis-Decenoic Acid”, we found the 2-cis-decenoic acid is produced by Pseudomonas aeruginosa under stress to degrade the biofilm of other organism. Including the biofilm of Xylella fastidiosa, indeed the 2-cis-decanoic acid seems to inhibit the induction of genes depending on the quorum sensing of Xylella fastidiosa and therefor its biofilm. Again in according to the paper “The Putative Enoyl-Coenzyme A Hydratase DspI Is Required for Production of the Pseudomonas aeruginosa Biofilm Dispersion Autoinducer cis-Decenoic Acid”, the enzyme DspI is necessary to the production of 2-cis-decenenoic acid by Pseudomonas aeruginosa, so we search the DNA sequence of the enzyme DspI in the genome of Pseudomonas aeruginosa to create our first biobrick ( part ).



Cis-2-decenoic acid effect (DA) on biofilm production'

According to the paper “The Putative Enoyl-Coenzyme A Hydratase DspI Is Required for Production of the Pseudomonas aeruginosa Biofilm Dispersion Autoinducer cis-Decenoic Acid”, biofilm dispersion assays are performed by addition of cis-2-decenoic (DA) acid with a concentration of 310 nM.

We tested the effect of this fatty acid on Xanthomonas and Pseudomonas in differents parameters:fatty acid concentration, medium for bacteria, type of tube. The point of theses experiments are to show the effect of this molecule on biofilm production when we add it in medium at different moments of growth. To charaterize the quantity of biofilm, we use purple crystal coloration, that mark on tube a ring of biofilm. Then we mesure with TECAN the quantity of biofilm.


Mesure OD600nm plaque bottom TECAN

T--Aix-Marseille--plaqueviolettecan.jpeg