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HOME	TEAM	PROJECT	SOFTWARE	MODELING	WET LAB	PARTS	HUMAN PRACTICE	JUDGING CRITERIA

Protocols

Plates preparation

Autoclave LB medium with 2% agar.
Cool (at about 50°C, to prevent agar polymerization).
Before pouring the plates add antibiotic (Ampicillin 1000x [ ] or Kanamicin 200x [ ]).
Put about 20ml of medium per plate.
Leave it solidify and store at 4°C.

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Transformation

Thaw the competent cells in ice (do not refreeze).
Dispense 80μl of cells into microfuge tubes on ice.
Add 0.1-0.3μg of plasmidic DNA or the respective amount of the ligation reaction.
Keep on ice for 30min.
HeatShock at 42°C for 60sec without agitation.
Keep on ice for 2min.
Add 0.8ml of LB medium at room temperature.
Incubate at 37°C for 1hr with agitation.
Pellet the cells and discard most of supernatant, leaving about 100μl.
Streak on plates containing appropriate antibiotics.
Incubate the plates overnight at 37°C.

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Inoculation

Put 5 ml of LB media in a 50ml tube.
Add the appropriate antibiotic.
Pick one colony from the plate with the inoculation loop
Put cells in solution.
Incubate the plates overnight (12 hours) at 37°C.

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Miniprep

Pellet for 10 mins at 4400 rpm and discard most of supernatant.
Resuspend pelleted bacterial cells in 250μl of Buffer P1 and tranfer to a microcentrifuge tube.
Add 250μl of Buffer P2 and mix thoruoghly by inverting the tube 4-6 times.
Add 350μl of Buffer N3 and mix immediately and thoruoghly by inverting the tube 4-6 times.
Centrifuge for 10 min at ~18,000 x g in a table-top microcentrifuge.
Apply the supernatant (from step 4) to the QIAprep spin column by decanting or pipetting.
Centrifuge for 30-60 s. Discard the flow-though.
Recommended: Wash the QIAprep spin column by adding 0.5 ml of Buffer PB and centrifuging for 30-60 s. Discard the flow through.
Wash QIAprep spin column by adding 0.75ml of Buffer PE and centrifuge for 30-60 s.
Discard the flow through and centrifuge for an additional 1 min to remove residual wash buffer.
To elute DNA, place the QIAprep column in a clean 1.5 ml microcentrifuge tube. Add 30μl of Buffer EB (or water) to the center of each QIAprep spin column, let stand for 1 min, and centrifuge for 1 min.

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Digestion reaction

E/S cut: enzyme 1 --> ECO R1; enzyme 2 --> SPE; buffer --> ECO R1

X/P cut: enzyme 1 --> Xba; enzyme 2 --> Pst 1; buffer --> 3

S/P cut: enzyme 1 --> SPE; enzyme 2 --> Pst 1; buffer --> 2

E/P cut: enzyme 1 --> ECO R1; enzyme 2 --> Pst 1; buffer --> ECO R1

Mix:
- 0.5 μl of BSA
- 0.5μl of each enzyme
- 3μl of buffer
- 5μl of DNA
- 20.5μl of H2O(most pure)
Spinning down.
1h at 37 °C.
20 min at 80 °C to block the enzymatic action.
Put in ice.
Start run preparation.

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Gel preparation

150ml of Buffer TBE 1x.
Add the appropriate quantity of Agarose for the desired thickness
- 0.7%= 1g of agarose
- 0.7-1% general( from 200 bases to 3Kb)
- 0.5% big pieces (6-7 Kb)
- 2-3% small pieces (100 bases)
Microwaves for 2 min.
Cool down under flowing water.
Add 10μl of EtBr.
Prepare the gel tray and set in place the wide-thoot comb.
Pour the gel in the gel tray (work in the hood for safety purpose)
Get rid of bubbles and let solidify.

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Electrophoretic run

Put the solidified gel in the apposite run container.
Check that TBE fully covers the gel.
Gently extract the comb.
Add the Loading buffer in the digested DNA.

Loading: substance that loads the sample with dye so that we can see the evolution of race and weight the DNA so that deposits in the well; concentrated at 6x.

Make the deposit in the wells of the samples and loading of reference (a part of loading should be prepared to scale by reference).
Close the container.
Start the run:
- 50/100 V --> until separate bands
- 120 V --> until half run
- 140 V--> until end of run.

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Gel extraction

Excise the DNA fragment from the agarose gel with a clean, sharp scalpel.
Weigh the gel slice in a colorless tube. Add 3 volumes of Buffer QG to 1 volume of gel (100 mg ~ 100 μl).
Incubate at 50°C for 10 min (or until the gel slice has completely dissolved). To help dissolve gel, mix by vortexing the tube every 2-3 min during the incubation.
After the gel slice has dissolved completely, check that the color of the mixture is yellow (similar to Buffer QG without dissolved agarose).
Add 1 gel volume of isopropanol to the sample and mix.
Place a QIAquick spin column in a provided 2 ml collection tube or into a vacuum manifold.
To bind DNA, apply the sample to the QIAquick column and centrifuge for 1 min or apply vacuum to the manifold until all samples have passed through the column. Discard flow-through and place the QIAquick column back into the same tube.
Recommended: add 0.5 ml of Buffer QG to QIAquick column and centrifuge for 1 min or apply vacuum. Discard flow-through and place the QIAquick column back into the same tube.
To wash, add 0.75 ml of Buffer PE to QIAquick column and centrifuge for 1 min or apply vacuum. Discard flow-through and place the QIAquick column back into the same tube.
Centrifuge the column in a 2 ml collection tube (provided) for 1 min at 18,000 x g.
Place QIAquick column into a clean 1.5 ml microcentrifuge tube.
To elute DNA, add 30 μl of Buffer EB (10 mM Tris-Cl, pH 8.5) or water to the center of the QIAquick membrane and centrifuge the column for 1 min. Alternatively, for increased DNA concentration, add 30 μl of elution buffer to the center of the QIAquick membrane, let the column stand for 1 min and then centrifuge for 1 min.
If the purified DNA is to be analyzed on a gel, add 1 volume of Loading Dye to 5 volumes of purified DNA. Mix the solution by pipetting up and down before loading the gel.

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Ligation reaction

Ligation with one insert and one vector --> f.v.=20μl
- 8μl of insert
- 4μl of vector
- 1μl of T4 ligase
- 4μl of Buffer 5X
- 3μl of H2O mQ
Ligation with two insert and one vector --> f.v.=30μl
- 4μl of vector
- 8μl of insert 1
- 8μl of insert 2
- 1μl of T4 ligase
- 6μl of Buffer 5X
- 3μl of H2O mQ
Conservation:
- 40 min at Tamb, or
- 3 hours at 15°C

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Chemiocompetent cells

Take some colonies of DH5α cells from a fresh streaked plate and inoculate into 125ml of Soc medium.
Grow the cells overnight at 25°C (it is advised to grow them slowly in order to have them better synchronized). It takes approximately 20 hours. It is advisable to grow the cells at 25°C overnight and then to shift them at 37°C. Bacteria are ready for harvesting when OD600 is between 0.37 and 0.4. Higher OD will lead to less competent cells (it is important to harvest the bacteria when they are still in the logarithmic phase of growth).
Spin down the cells (at maximum speed) at 4°C for 10 min.
Re-dissolve the pellet in 40ml of Transformation buffer.
Incubate on ice for 10 min.
Spin down the cells (at maximum speed) at 4°C for 10 min.
Re-dissolve the pellet in 10ml of Transformation buffer.
Add 700μl of DMSO.
Aliquot (200μl) and freeze at -80°C.

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Mediums and buffers

Soc medium

To prepare 1l of SOC medium dissolve in ultrapure water:
- Tryptone 4g
- Yeast extract 1g
- 1M NaCl 2ml
- 1M KCl 0.5ml
- 5M NaOH 200μl to adjust the pH to 6.8
After autoclaving add 2ml each of 2M Mg-salt (1M MgSO4 and 1M MgCl) and 2M glucose.

LB medium

To prepare 1L of LB medium dissolve in ultrapure water:
- Tryptone 10g
- Yeast extract 5g
- NaCl 10g
- 5M NaOH 200μl
Autoclave and store at room temperature.

Transformation Buffer

(always made fresh)

To prepare 100ml dissolve in ultrapure water:
- (15mM) CaCl2 0.2205g
- (250mM) KCl 1.864g
- (10mM) Pipes 0.302g
Adjust pH with KOH to 6.7.
Add (55mM) MnCl2 (0.89g of MnCl2x2H2O).
Filter with 0.22μm filter.

M9 medium

Dissolve 56.4g in 1l of distilled water.
Autoclave for 15 min at 121°C.

This convenient 5x concentrate can be stored and diluted as needed to prepare 5l of 1x M9 minimal salts. For M9 minimal medium:

Aseptically dilute 200ml of M9 minimal salts, 5x[ ] with 800mL of sterile water, if necessary, cool to 45-50°C.
Aseptically add 20ml of sterile 1M glucose and 2mL of sterile 1M magnesium solfate to prepare 1l of M9 minimal medium.
If desired aseptically add 0.1ml of 1M sterile calcium chloride to the M9 minimal medium. M9 minimal medium may also be supplemented with the appropriate amino acids.

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Antibiotics stocks preparation

Ampicillin

Dissolve ampicillin in ultrapure water 100mg/mL (stock 1000x [ ], working concentration100 μg/mL).
Aliquot and store at -20°C.

Kanamicin

Dissolve Kanamicin in ultrapure water 10mg/mL (stock 200x [ ], working concentration 50μg/mL).
Aliquot and store at -20°C.

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IPTG stocks preparation

IPTG (Isopropyl β-D-1-thiogalactopyranoside) 100mM stocks preparation for Plac induction (IPTG MW=238.31):
- 0.476g in 20ml of ultrapure water. Working concentration 1mM

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Fluorescence test

Growth O/N for 15h in LB (5ml) of:
- transformed E. coli with appropriate antibiotic;
- E. coli.
All measures must be done in M9 with OD=1.2.
The day after, in the morning, measure OD.
To obtain OD=1.2:
- centrifuge 4ml of bacterial culture at 4400rpm for 3min at 25°C;
- discard the supernatant;
- resuspend the cell pellet in 6ml of M9 medium with glucose and appropriate antibiotic (1000x [ ]).
Measure OD: adjust OD to 1.2 through further dilution or cell growth.
Adjust PMT offset with untransformed E. Coli.
Test culture fluorescence before IPTG induction.
IPTG induction:
- centrifugate bacteria culture at 4400rpm for 3min at 25°C;
- discard the supernatant;
- resuspend cell pellet in M9 medium and 2mM IPTG with appropriate antibiotic (1000x [ ]);
Incubate at 37°C.
Test fluorescence after 10min, 20min, 30min, 1h, 2h.

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M9 supplemented media

For 1L of 1X media

200 mL 5X M9 minimal salts
1. Dissolve 56.4 g Bacto M9 minimal salts, 5X from Difco in 1L H2O
2. Separate into 200 mL aliquots
3. Autoclave to sterilize. 121°C for 15 minutes.
34 mL 10 mg/mL thiamine
1. Dissolve 10 mg per mL of H2O
2. Use a 0.22 μm filter to filter-sterilize
10 mL 40% glycerol
1. Add 80 mL glyerol to 120 mL of H2O
2. Autoclave to sterilize
20 mL 10% Casamino acids
1. Dissolve 50 g Bacto Casamino acids from Difco in 500 mL H2O
2. Autoclave to sterilize
2 mL 1M MgSO4
1. Dissolve 24.65 g MgSO4·7H2O in 100 mL H2O
2. Autoclave to sterilize
100 μL 1M CaCl2
1. Dissolve 14.7 g CaCl2·2H2O in 100 mL H2O
2. Autoclave to sterilize
733.9 mL H2O
1. Sterilize deionized water in autoclave

Combine above solutions using sterile technique. (May notice some precipitation during preparation but precipitate should go back into solution once volume is brought up to 1L with sterile H2O.) Add antibiotic as appropriate and store at 4°C

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 <font size="4">Chemiocompetent cells</font>

Team:Bologna/WetlabProtocols

From 2009.igem.org

Revision as of 15:04, 21 October 2009

Protocols