IGEM:Cambridge/2008/Protocols

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Agarose Gel

Used for Electrophoresis when extracting any product afterwards.

Making the Gel

• Agarose Gel is made by adding the appropriate mass of Ultrapure Agarose (usually 0.8g) to a duran bottle, and then adding 100ml of TAE buffer to the bottle. 10μL of SyBr Green (10000x) can be added if necessary.
• The whole is then microwaved at high for 1 minute, stood for 3 minutes and again heated for 1 minute. Boiling should be avoided and the powder should fully dissolve. It should then be left to cool.
• The ends of the gel tray must be taped with autoclave tape and firmly sealed.
• When the solution is hand hot the gel can be poured. Pipette around 1ml of the solution up each of the taped ends of the gel tray to prevent leakage. Insert the comb and pour the gel to around 6ml.
• Leave to set and remove the comb and tape.

Loading the Gel

• Mix around 17μL of DNA sample with 3μL of loading dye. The exact amount of DNA varies according to solution strength, but should be around 80ng
• Place the gel tray with gel into the running bay (wells at black end) and add enough TAE buffer to just cover the gel.
• Carefully load around 20μL of sample into wells, including some ladder as reference. Normal Agarose gels do not need to have every well filled - there is TAE in them already.

Running the Gel

• Connect up the red lead to the red terminals and the black lead to the black terminals of the power supply and the running bay.
• Make sure the wells are at the black end.
• Set the power supply to 80 volts and switch it on.
• Check the gel every 20 mins or so to make sure that the gel is running the right way and that the yellow dye (equivalent to 60bp) has not run to the end of the gel.
• When the front dye has reached about 3/4 of the way to the end of the gel turn the power supply off and disconnect the leads.

Visualising the Gel

• If no SyBr green has been added the gel needs to be placed in the EtBr solution for 20 mins.
• Drain the gel and place in the UV visualiser.
• If extracting make sure the prep UV button is pressed, and take a picture of the gel.
• To extract the gel slide the light tray out, ensure shielding for all who are involved, and carefully cut out the gel fragment, usind prep UV.
• SyBr Green gels can also be visualised using special visualisers.

Biobrick Extraction

We found we could not extract enough DNA from the registry, so we are upgrading the extraction to the "bigger, better, faster, stronger" method.

• Warm 50μL of EB in Eppendorf tubes at 50°C and add 4 punched spots.
• Keep it at 50°C for 20mins
• Spin down for 3 minutes at 13,000 g.
• Warm for 10mins
• Spin down again for 3mins.
• Pipette off the supernatant which should contain DNA.

We then confirmed with PCR.

E-Gel

Our E-gel machine from invitrogen

E-Gel is used to confirm size of prodicts, but not for extraction.

• The E-Gel must be prepared by placing inside the Gel Dock and running the Pre-run for 2 minutes.
• The Gel can then be loaded. 19μL of DNA, made up with SDW as necessary, is added to each well, and 1μL of loading dye is also added. Adding less dye allows a more sharply defined band.
• All unloaded lanes must be filled with SDW, to ensure correct running.
• The gel is then run, using the Run program, for 26 mins.
• The gel can then be visualised in the UV visualiser, for EtBr, or using the E-Gel visualiser, for SyBr Green.

Fast Digestion

The following are added to a 1.5μL eppendorf:

• 2μL plasmid DNA
• 2μL 10x fast digest buffer
• enough water to make up to 19μL (18μL if double digest)
• 1μL of each fast digest enzyme

If using PCR product the whole is made up to 30μL, using 10μL DNA and 3μL buffer.

The tubes are then incubated at 37°C for 5mins and then the enzyme inactivated at 80°C for 15mins

Fast Ligation

The following are added to a 1.5μL eppendorf:

• xμL vector DNA
• xμL gene DNA
• 1.5μL 10x fast digest buffer
• 1.5μL 10mM ATP
• enough water to make up to 15μL
• 1μL of fast ligase enzyme

The tubes are then incubated at room temperature for 5mins and then the enzyme inactivated at 75°C for 15mins

Flame Photometry

Chris attempts to unravel the secrets of the Flame Photometer

Set Up

• Make sure discharge pipe (on right hand side) is placed in something to collect discharge, and valve is not completely shut.
• Check clear tube is connected to compressor OUTLET, and securely attached.
• Turn on compressor.
• Gauge on back of photometer should read 12psi.
• Check gas pipe is attached at tap.
• Turn on gas.
• Wait 1 minute.
• Turn on photometer. It should click, and orange "flame on" light should come on.
• Place beaker of distilled water in the photometer tray, and make sure thin tube reaches water.
• Wait 15 minutes before taking any readings.
• Use "blank" dial to adjust reading to 0 for distilled water.

Taking readings

• Place thin tube into sample, far in, as the liquid will be taken up quite rapidly.
• Wait for reading to stabilise (reading may continue to fluctuate at high values) and take reading.
• Place tube in distilled water beaker between each sample, waiting until reading returns to 0.

In case of compressor blow-out

• Turn off gas at tap.
• Turn off photometer.
• Turn off compressor.
• Redo set up steps, with 15 minute waiting time reduced to 5, as the equipment will already be almost up to temperature.

In case of wildly fluctuating "zero" readings

• Tap digital display.
• Allow tube to dry (take out of SDW) before loading next sample.

Gel DNA Recovery (Zymoclean)

• Add 3 parts ADB Buffer to 1 part Gel volume
• Incubate 55°C for 5-10 minutes, until gel melts
• Place solution into Zymo-Spin column and then into a collection tube
• Spin for 30 seconds. Empty collection tube when necessary
• Add 200μL Wash Buffer. Spin for 30 seconds. Repeat wash step.
• Place column into Eppendorf. Add 6-10μL SDW to elute DNA. Add more SDW to elute more DNA - normally 20μL.

Oxygen Electrode

For the protocol see http://www.rankbrothers.co.uk/download/digioxy.pdf

Plasmid Miniprep (Zyppy)

• Add 100μL 7x Lysis Buffer to 600μL Cell Culture. Invert 4 to 6 times
• Add 350μL cold Neutralization Buffer. Invert 4 to 6 times
• Centrifuge 13,000g for 2 minutes
• Transfer supernatant to Zymo-Spin column
• Place column in a collection tube and spin for 15 seconds. Discard flow through
• Add 200μL Endo-Wash Buffer. Spin for 15 seconds
• Add 400μL Zyppy Wash. Spin for 30 seconds
• Transfer column to clean Eppendorf. Add 30 to 100μL Elution Buffer to the column and spin for 15 seconds to elute DNA

Primer Preparation and Storage

Sigma Primers arrived as tubes of dried oligos

• Suspend in sterile distilled water (SDW) to form a 100μM stock solution - stored at -20°C
• 10μM aliquots taken using 10μL stock and 90μL SDW - stored at 4°C

PCR

Our Piko PCR machine provided by Finnzymes

To make 50μL of PCR mix the following were added to Eppendorf tubes:

• 5μL of DNA in EB buffer
• 2.5μL of each primer
• 25μL of 2x Finnzymes mastermix
• 15μL of sterile distilled water

These values can be adjusted for any volumes of final mixture.

The total final volume is transferred to thin walled tubes (may need to be spun down) and then placed in a PCR machine and the appropriate program run.

Transformation

First chemically competent cells are made

• Cells are grown for 1 hour in LB and pelleted (at 6500rpm for 1 min.)
• Pellet is resuspended in 1mL 50mM CaCl
• Again cells are pelleted.
• Pellet is resuspended in 200μL 50mM CaCl

To transform cells

• To chilled tubes add 5μL of plasmid DNA + EB solution to 5μL of Cells (Chemically competent cells)
• Ice for 30 minutes
• Heat shock at 42°C for 60 seconds
• Ice for 2 minutes
• Add 500μL of SOC
• Incubate at 37°C for 2 hours

After transformation cells need to be grown under selection conditions.