Team:Utah State/Protocols

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'''Method'''  

1. Resuspend DNA in 40 l water, vortex, and do a brief centrifuge to get solution to the bottom of the tube.

2. Add components to the digestion solution in the following order:  DNA (23 l), 10X Tango buffer (3 l), Xba1 (2 l), and Pst1 (2 l).  The volume and restriction enzymes can be varied, but it should be ensured that the total volume is 10X the amount of Tango buffer added.  Tap tubes periodically and allow to digest while preparing electrophoresis gel.

3. Prepare electrophoresis gel by adding 2 g agarose to 200 ml TAE (1% solution).  This is best done in an Erlenmeyer flask of adequate volume as swirling will need to be done.  Place in the microwave and microwave on high for 20 seconds at a time, pulling it out and swirling until solution is homogeneous again, then repeating (BE CAREFUL to watch the solution closely when swirling it superheats and can boil over and cause severe burns).  Continue until solution is seen boiling in the microwave then gently swirl again.

4. Add 20 l ethidium bromide to solution and swirl until dissolved evenly.

5. Add 6 l of 6X loading dye to each tube of digested DNA solution.

6. Prepare the electrophoresis unit by orienting the basin sideways with rubber gaskets firmly against the side.  Place desired well template in the basin.  

7. When the agarose solution is cool enough to comfortably touch the flask, pour into the basin until the solution is about of the way to the top of the well template.

8. When the gel is solidified (should look somewhat cloudy), remove the well template and change basin orientation to have the wells closest to the negative pole (as the DNA will flow towards the positive pole).  Pour 1X TAE buffer into both sides of the electrophoresis unit until it just covers the gel and fills the wells.  

9. By inserting the pipette tip below the TAE liquid and into the well, add 10 l of DNA ladder solution to first (and last if desired) well, skip one well, then begin adding the digested DNA solutions to the wells by adding about 2 l less than the total volume in the tubes to prevent air bubbles in the wells.  

10. Place the cover on the electrophoresis unit, plug into the power source, and turn on voltage to 70 V (this can be as high as 100 V if time is an issue), and press the start button.  Separation should take two to three hours.  The yellow dye shows the location of the smaller nucleotide lengths and the blue dye shows the location of the larger nucleotide lengths.  DNA separation can be observed as time goes on by turning off the power supply then gently removing the basin from the electrophoresis unit (be careful not to let the gel slip out of the basin) and placing on the UV transilluminator to see DNA bands.  The basin can then be placed back in the electrophoresis unit for further separation if desired.  Take care to not have the power supply on without the lid to the unit in place.  

11. When the desired level of separation is attained, the basin can be placed on the transilluminator for picture taking.  Place the cone-shaped cover over the transilluminator and place the digital camera in the top hole for pictures.  

For all experimentation involving the need for bacterial biomass and experimentation, proper media is needed to grow the cells. The following is the mediFollowing successful bacterial cloning and isolation, it is important to verify that the target gene is in the cell and that the plasmid is functional. To do this, it is a common practice to sequence the DNA plasmid. To obtain enough DNA for sequencing, the bacterial clones are grown in a liquid culture. The cells are harvested by centrifugation and then prepared for DNA plasmid extraction. DNA plasmid extraction can be done several ways, and the overall purpose is to lyse the cells and separate the plasmid DNA from all other cellular proteins, DNA, and debris. The following is the method used by the USU team to isolate the plasmid DNA containing the PHB biobricks.a composition and methods used by USU to prepare the media.

1. Add 5 g yeast extract, 10 g NaCl, 10 g Bacto Tryptone, and 15 g agar (if desired) to a 2 L Erlenmeyer flask and bring the volume up to 1 L with ddH20.  Mix by swirling.  Cover top with foil.  

2. Autoclave for 45 minutes (liquid setting, 0 minutes drying time).  It will take an additional half hour for the autoclave to finish cooling then an additional 20 to 30 minutes until the media is cool enough to pour.  

1. Add 40 ml 50X TAE solution to a 2 L flask and bring level up to 2 L with ddH20.  

PCR is used to amplify a desired DNA sequence. The reaction is first set up by designing primers that will bind only to the desired regions of the DNA sequence. Once the primer and polymerase have been selected, the reaction parameters of time and temperature must be optimized. When the reaction works properly only the target DNA will be amplified into large quantities that may then be isolated and used for further experimentation. The following is the procedure used by USU for PCR reactions to amplify the PHB synthesis and promotion genes.

'''Method'''  

1. Obtain the following reagents from the freezer:  DNA template (cells or DNA), 10X Taq buffer (+KCl, -Mg/Cl<small>2</small>), MgCl<small>2</small>, 10 mM dNTP Mix, Taq polymerase (take out of freezer only immediately when needed and put back), and sterile distilled H<small>2</small>O.  Place all reagents on ice.  Also obtain PCR (either 0.2 or 0.5 ml) tubes.  

2. Add the following reagents to a tube (50 l reaction) in the following volumes and order:  

32 l sterile H<small>2</small>O,  

5 l 10X buffer,

2 l dNTP Mix,

6 l MgCl<small>2</small>  

3 l cells/DNA,

0.25 l Taq Polymerase  

1 l primer 1  

1 l primer 2  

MgCl<small>2</small> volume can be varied (lower to increase specificity just ensure total volume is 50 ul with H<small>2</small>O).  If many reactions are to be constructed, a master mix can be made up to cut down on time and pipette tip usage (if this is done, ensure primers are added to the appropriate reaction, i.e. perhaps not to the master mix).  Tap or vortex tubes and take to the thermocyler.  Place all reagents back in the -20C freezer.  

3. Choose thermocycler temperatures.  The Eppendorf Mastercycler will cycle between three temperatures:  typical temperatures are 94C for denaturing, 50-60C for primer annealing, and 72C for polymerase extending.  Lowering the annealing temperature decreases DNA specificity; 55C is a good temperature to begin if no trials have been made with the sample.  

4. Turn on thermocycler with the switch in the back of the unit and open the lid.  The placement of the tubes depends on the size of the tube (0.2 or 0.5 ml) and whether or not a temperature gradient is to be used.  

* If no gradient will be used, tubes can be placed anywhere on the unit in the appropriately-sized hole. Select Files and press enter.  Select Load and then Standard.  If cells will be used in the reaction, include a 1-minute lysing step at the beginning (step 1); this will be followed by a 1-minute DNA denaturing step (step 2).  If purified DNA will be used, set step 1 to 1 second.  Set an annealing temperature for step 3.  Ensure the lid temperature is 105C and the extending temperature is 72C.  Press exit.  If prompted to save, save by pressing enter three times.  Press exit to return to the main menu.  Choose Start on the main menu and select Standard.  The program should begin.  

* If a gradient is to be used, temperature will vary according to column.  A 20C range is the maximum range that can be used (+/- 10C).  The range is made by setting a temperature for the middle column and then setting a +/- range.  To see what the temperatures will be if a gradient is used, select OPTIONS on the main menu, then select Gradient.  Select the size tube that is being used by pressing Sel, then press enter.  Choose a temperature for the center column, press enter, then select a +/- range and press enter.  The column number along with the corresponding temperature is shown.  Decide tube placement based on this information.  Press exit twice to return on the main menu.  Select Files then Load, then Gradient.  If cells are being used, set the cell lysing step (step 1) to 1 minute (1:00); if purified DNA is being used, set this time to 1 second (0:01).  Step 2 should be 94C, Step 4 should be 72C, and the lid temperature should be 105C.  Go to step 3 and set an annealing temperature for the center column.  Leave the next two lines as they are, and change the gradient setting (G) to the +/- the center temperature amount.  Press exit.  If prompted to save, press enter three times; if not prompted to save, press enter once.  Press exit to get back to the main menu.  To begin cycle, select Start, then select Gradient.  The program should begin.  

5. The thermocycler is set to store the completed reaction tubes at 4C when finished.

Ligation is the process by which the insert (target DNA gene) is inserted into a plasmid. Both the plasmid and insert have been digested and have the proper sticky or blunt ends which are compatible for joining the two DNA pieces together into one molecule. These two DNA pieces are placed in a reaction tube and the proper DNA ligase, buffer, and cofactors are added for the reaction to take place. When done properly, the ligation will result in a successful combination of the insert and plasmid into one plasmid. This newly formed plasmid may then be isolated using gel electrophoresis and then used for bacterial transformation or other experimentation. The following is the procedure used by USU to ligate PHB genes into the biobrick plasmids.

'''Method'''  

1. Obtain the following reagents, some of which are in the -20C freezer:  DNA vector, DNA insert, 10X ligation buffer, T4 DNA ligase (take out only when needed, then return immediately to freezer), and sterile distilled water.  

2. Ideally, it is desirable to have the concentration of insert ends (or moles of insert) be two to three times the concentration of vector ends (or moles of vector), with a total DNA concentration of 50-400 ng/l in the reaction.  If determining the DNA concentration is not possible, place two to three times the volume of vector as the volume of insert in the reaction.  As this is often the case, place the following reagents in a thin-walled PCR tube in the following volumes:  

10 l insert DNA  

3 l vector DNA  

2 l 10X ligation buffer  

4 l H2O  

1 l T4 DNA ligase  

= ''20 l total''  

This could also be done in different volumes depending on DNA concentration/total volume desired.  

3. Gently mix the tube, and place the tube in the PCR thermocyler, turn on the machine, select Start, from the main menu, select 22 and press Start.  The thermocycler will keep the reaction at 22C.  

4. Incubate for 60 minutes.  Heat-inactivate by placing tubes in 68C water bath for 10 minutes.  Place in the freezer if storing for later use.  

 

1. Collect cells (confluent T-25) by trypsinization and spin.

2. Lyse the pellet with 100 l lysis buffer on ice for 10 min.

*For 500,000 cells, lyse with 20 l.

3. Spin at 14,000 rpm (16,000 g) in an Eppendorf microfuge for 10 min at 4C.

4. Transfer the supernatant to a new tube and discard the pellet.

*(We use the Bradford assay from Bio-Rad.)

6. Take x l (= y g protein) and mix with x l of 2x sample buffer.

7. Boil for 5 min.

8. Cool at RT for 5 min.

9. Flash spin to bring down condensation prior to loading gel.

10. Assemble gel in gel rig.

11. Prepare protein samples (10 g will suffice).

12. Use 5 l of Kaleidoscope standard.

13. Run at 200 V (constant voltage) for 30 min.

14. Cut a piece of PVDF membrane (Millipore Immobion-P #IPVH 000 10).

15. Wet for about 30 min in methanol on a rocker at room temp.

16. Remove methanol and add 1x Blotting buffer until ready to use.

17. Assemble "sandwich" for Bio-Rad's Transblot.

*        Sponge - filter paper - gel - membrane - filter paper - sponge

19. Transfer for 1 hr at 1 amp at 4C on a stir plate.  

*        For the Mini-Transblot, it's 100 V for 1 hr with the cold pack and prechilled buffer.

20. When finished, immerse membrane in Blocking buffer and block overnight.

21. Incubate with primary antibody diluted in Blocking buffer for 60 min at room temp.

22. Wash 3 x 10 min with 0.05% Tween 20 in PBS.

23. Incubate with secondary antibody diluted in Blocking buffer for 45 min at room temp.

24. Wash 3 x 10 min with 0.05% Tween 20 in PBS.

25. Detect with Amersham ECL kit (RPN 2106).

26. Rinse blot off with 0.05% Tween 20 in PBS.

27. Put blot into Kapak bag cut to slightly bigger size than blot.

28. Add about 5 to 10 ml Stripping buffer.

29. Remove as much air as possible and seal bag.

30. Immerse into 80C water bath and incubate for 20 min.

31. Rinse blot off with 0.05% Tween 20 in PBS.

32. Block for about 1 hr with 5% BSA/Tween 20, or overnight with 3% BSA/Tween 20.