Difference between revisions of "Team:IIT Delhi/protocol"
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| + | <li>Inoculate 5 ml of rich medium (LB, YT, or Terrific Broth) containing the | ||
| + | appropriate antibiotic with a single colony of transformed bacteria. | ||
| + | Incubate the culture overnight at 37°C with vigorous shaking at 200 | ||
| + | rpm. | ||
| + | <li>Pour 2 ml of the culture into a microfuge tube. Centrifuge at maximum | ||
| + | speed(13400 rpm) for 4-5 minutes in a microfuge. Store the unused | ||
| + | portion(if any) of the original culture at 4°C. | ||
| + | <li>Remove the medium by aspiration(upar se nikal liyo), leaving the | ||
| + | bacterial pellet as dry as possible. | ||
| + | <li>Resuspend the bacterial pellet in 100 μl of ice-cold Alkaline lysis | ||
| + | solution I by vigorous vortexing. | ||
| + | <li>Add 200 μl of freshly prepared Alkaline lysis solution II to each | ||
| + | bacterial suspension. Close the tube tightly, and mix the contents well | ||
| + | by inverting the tube. | ||
| + | </ol> | ||
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<button class="accordion back1" style="font-weight: bold;">Section 5</button> | <button class="accordion back1" style="font-weight: bold;">Section 5</button> | ||
Revision as of 18:45, 31 October 2017
LAB PROTOCOLS
Accurate Experimenting for Accurate Results !!
- Dilute an overnight culture of E. coli 1:200 with LB broth.
- Incubate at 37°C with shaking (at 200 rpm) until the cells reach early log phase (OD600 = 0.25-0.4).
- We already have 1X TSS in 4 deg fridge(old). Use it without dilution or thawing. Keep it inside the icebox just after taking out from the fridge.
OR
(if the above 1X TSS is not available)
While cells are growing, thaw 2X TSS on ice and dilute an appropriate amount 1:1 with sterile distilled water (100µl of diluted TSS will be needed for each ml of cells). Chill on ice. - Place 2-ml aliquots of early log-phase cells into sterile 2-ml micro-centrifuge tubes and pellet the cells by centrifugation at 4°C at 3000g for 10 min.(6-8 mins for taking part from Igem kit)
- Remove the supernatant and discard. Add 0.2 ml of the ice-cold 1X TSS and place the tubes on ice.
- Gently suspend the cells by pipetting.
- Proceed with the transformation protocol below (Step 2), or immediately freeze cells by immersion in liquid nitrogen or a dry ice/ethanol bath. Store the frozen cells at –70°C.
- Thaw frozen TSS-competent cells slowly on ice(if stored at -70°C).
- Add 100 pg -200 ng (2.5 to 4 ul)(15ul for ligation product)of DNA to each tube of competent cells.
Note:Addition of more than 10ng of DNA may significantly decrease transformation efficiencies. - Flick the tubes to mix the cells and DNA and incubate the cells on ice for 30 minutes.
- Transfer the tubes to water bath/dry bath(42°C) for 90 seconds.
- Transfer the tubes to ice and incubate for an additional 10 minutes.
- Add 800 ul (total 1 mL)of LB broth and incubate the cells at 37°C for up to 1 hour with shaking (at 200 rpm).
- Centrifuge the cells at 3000g for ~ 6min (10 mins after ligation)at 4deg(in temperature control centrifuge).
- Aspirate the tubes to leave the pellets with 1/4 broth .(keep ~300ul)
- Plate the cells on-to the appropriate selective or differential medium and incubate overnight at 37°C.Check the procedure for antibiotic.
- For Ampicillin: 12ul Amp + 188 ul MQ. In MCT spread it on the culture plate before adding the DNA.
- For Chloramphenicol: 1:1000 volume ratio of antibiotic : culture broth. Directly suspend into the culture broth and spread it on the plate.
- For Kanamycin: 1:1000 volume ratio of antibiotic : culture broth. Directly suspend into the culture broth and spread it on the plate.
- DNA should be added as soon as the last trace of ice in the tube disappears.
- Incubate on ice for 30 minutes. Expect a 2-fold loss in TE for every 10 minutes you shorten this step.
- Perform all the steps gently
- Wash twice with tap water, jerk it off
- Wash twice with distilled water, jerk it off
- Put ethanol in plates and stand for 5 min
- Jerk it off
- Put open plate in oven for 20 minutes
- Put closed plate in UV for 10 minutes
- Prepare sufficient electrophoresis buffer (usually 1x TAE ) to fill the
electrophoresis tank and to cast the gel:
For example, we take 2ml of TAE stock solution in an Erlenmeyer flask and make the volume to 100ml by adding 98 ml of distilled water. The 1x working solution is 40 mM Tris-acetate/1 mM EDTA.
It is important to use the same batch of electrophoresis buffer in both the electrophoresis tank and the gel preparation. - Loosely plug the neck of the Erlenmeyer flask using a paper cap. Heat the slurry in a boiling-water bath or a microwave oven until the agarose dissolves. The agarose solution can boil over very easily so keep checking it. It is good to stop it after 45 seconds and give it a swirl. It can become superheated and NOT boil until you take it out where upon it boils out all over your hands.
- When the molten gel has cooled to ~50 deg C, add 0.5μg/ml of ethidium bromide. Mix the gel solution thoroughly by gentle swirling.
- While the agarose solution is cooling, choose an appropriate comb for forming the sample slots in the gel. Apply cellotape tightly onto the sodes of comb to form a mold for gel.
- Pour the warm agarose solution into the mold.(The gel should be between
3 - 5 mm thick. Check that no air bubbles are under or between the
teeth of the comb).
- Allow the gel to set completely (30-45 minutes at room temperature), then pour a small amount of electrophoresis buffer on the top of the gel, and carefully remove the comb. Pour off the electrophoresis buffer. Mount the gel in the electrophoresis tank. Wash the Erlenmeyer flask as quick as possible. (Add just enough electrophoresis buffers to cover the gel to a depth of approx. 1mm).
- Mix the samples of DNA with 0.20 volumes of the desired 6x gel-loading dye on a clean piece of cello tape spread on an even surface.
- Slowly load the sample mixture into the slots of the submerged gel using a disposable micropipette or an automatic micropipettor or a drawn-out Pasteur pipette or a glass capillary tube. Load size standards into slots on both the right and left sides of the gel.
- Close the lid of the gel tank and attach the electrical leads so that the DNA will migrate toward the positive anode (red lead). Apply a voltage of 7-10 V/cm (measured as the distance between the positive and negative electrodes). If the electrodes are 10 cm apart then run the gel at 50V. It is fine to run the gel slower than this but do not run it any faster. Above 5V/cm the agarose may heat up and begin to melt with disastrous effects on your gel's resolution. If the leads have been attached correctly, bubbles should be generated at the anode and cathode.
- Run the gel until the loading dye has migrated an appropriate distance(~ 2/3 the length of gel) through the gel.
- Remove the gel tray and place directly on a UV transilluminator or under a gel doc.
-
Use TBE 1x for < 1000bp(can't extract DNA) and TAE for large DNA(12-15kb)
Percentage of agarose matters
Gel thickness should not be more than 3-4mm.
Comb should be cleaned well
Add buffer before removing the comb
- Inoculate 5 ml of rich medium (LB, YT, or Terrific Broth) containing the appropriate antibiotic with a single colony of transformed bacteria. Incubate the culture overnight at 37°C with vigorous shaking at 200 rpm.
- Pour 2 ml of the culture into a microfuge tube. Centrifuge at maximum speed(13400 rpm) for 4-5 minutes in a microfuge. Store the unused portion(if any) of the original culture at 4°C.
- Remove the medium by aspiration(upar se nikal liyo), leaving the bacterial pellet as dry as possible.
- Resuspend the bacterial pellet in 100 μl of ice-cold Alkaline lysis solution I by vigorous vortexing.
- Add 200 μl of freshly prepared Alkaline lysis solution II to each bacterial suspension. Close the tube tightly, and mix the contents well by inverting the tube.
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Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
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