Team:Paris/August 8

Minipreps: Plasmid extraction

Extraction of pSB3K3 et E0240 in pSB1A2 plasmid from overnight bacteria culture using the QIAspin Miniprep Kit (QIAGEN) by QIACube.

• Carried out 2 times (2 tubes)

Amplification of Genes of interest (OmpR, EnvZ, FlhDC)

We performed PCR on to amplify the sequence in order to have enough amount of DNA to carry out the following of our experiments.

PCR amplification

Protocol

• List of Oligos :

• Preparation of the templates :
  Resuspension of 1 colony in 100µl of water.

• Preparation of PCR mix :

For each sample,

1 µl dNTP
10 µl Buffer Phusion 5x
2,5 µl Oligo_F
2,5 µl Oligo_R
1µl template
1 µl Phusion
50 µl qsp H2O (33µl)

• Program PCR_Screening : Annealing 55°C - Time élongation 1'30" - Number cycle : 29

PCR verification/Analysis

Analysis of PCR product

After the PCR :

• 3µl have been analysed by electrophoresis
• the other 47µl of PCR products have been purified by the Promega kit.

• Electrophoresis

ladder : 10µl ladder 1 kb
samples : 3µl of PCR products + 2µl of Loading Dye
migration 30min at 100V, on a 1% agarose gel

• Results :

==> Conclusion : we observed the size expected for the PCR products, but not for FlhDC gene.
We hypothesis that its value of amplification for this gene it's low as we can't visualize it. So we try to continue to experiments to know if there is something inside or not this tube.

• Quantification of the PCR products purified

Blank : 2µl of buffer EB + 98µl of water
Samples : 2µl of PCR purified + 98µl of water.

• Results :

Digestion of PCR products

Protocol :

• Incubate 2h30 at 37°C

Analysis by electrophoresis

Analysis of PCR product digestion

• Conditions

ladder : 10µl ladder 1 kb
samples : 3µl of insert + 2µl of Loading Dye
migration 30min at 100V, on a 1% agarose gel.

• Results :

==> Conclusions : We validate the digestion of the vector and the insert. Now we are sure, that we don't detect anything for FlhDC genes.

The return of the promoters

Yesterday, we could not see anything on the electrophoresis after the digestion. Today, we will try the digestion again.

Protocol

Results

Results of the digestion of the promoters

To analyze our digestions, we made an electrophoresis.

• Gel : 1.5% Agar
• Ladder : 100 bp
• 4µL DNA + 2µL Loading Dye

    Conclusion
    *The bands are not visible on this picture, but with a long exposition time, we managed 
     to see the bands attheir right place.
    *The concentration of DNA is low!

We will do the ligation tomorrow.

Transformation with promotors of interest

Results

PCR Screening of Ligation Transformants

Use of 8 clones of Ligation transformants for PCR screening

Protocol of screening PCR

• Mix

25µl of Quick Load 2X
1µl of forward primer 10µM
1µl of reverse primer 10µM
23µl of water

• primers used

• 50µl of PCR Mix by tube/clone
• one toothpick of each clone's colony per tube
• Program : Annealing 55°C - Time élongation 1'30" - Number cycle : 29

• Conditions of electrophoresis

10µl of ladder 100 pb
10µl of screening PCR
migration ~30min at 100V on 1,5% gel

Results of electrophoresis

gel 1 gel 2

==> Conclusion:

• PCR of pFlgA, pFlgB and pFlhB have succeed, but we always have a problem with pFlhDC probably because of the primers which are not specific.

Building of the measurement plasmid

This morning we MiniPreped E0240 and pSB3K3 which are the two important parts of the standard measurement plasmid.

Before the digestion, we have to determine the DNA concentration of the MiniPreps

Measurement of DNA concentration

Digestion

Protocol

• X µL of Template DNA
• Buffer (n°2) 10X : 3µL
• BSA 100X : 0.3µL
• Pure water qsp 30 µL
• 1 µL of each enzyme

• Incubate during about 3h at 37°C, then 20 minutes at 65°C (to inactivate the enzymes).