Revision as of 11:40, 29 September 2018

Integrated Human Practices

PCR Plasmid Construction SSS Plasmid Construction SS Plasmid Construction SS Plasmid Construction SS

Gently mix the following reaction by pipetting and centrifuge briefly.

	20 μl system	50 μl system
Template	12～20 ng	30～50 ng
Forward primer	1.0 μl	2.5 μl
Reverse primer	1.0 μl	2.5 μl
dNTP	1.6 μl	4.0 μl
10x Buffer	2.0 μl	5.0 μl

Program of KOD DNA polymerase

Temperature	Time
94 ℃	3 min.	25～30 cycles
94 ℃ (Denaturation)	40 sec
57.5 ℃ (Annealing)	30 sec
72 ℃ (Extension)	Depend on sequence size (2 kbp/min. for Taq)
72 ℃	5 min.
4 ℃	∞

Confirm the size of the digested product by gel electrophoresis.
Gel purification of the target size.

Plasmid Construction

Digestion (vector)

Plasmid	200 ng	1000 ng
EcoRI / SpeI	0.2 μl	1 μl
XbaI / PstI	0.2 μl	1 μl
CutSmart Buffer	2 μl	5 μl
ddH2O	Up to 20 μl	Up to 50 μl
Digestion at 37℃ for 2.5hr.

Digestion (insert)

Plasmid	200 ng	1000 ng
EcoRI / XbaI	0.2 μl	1 μl
SpeI / PstI	0.2 μl	1 μl
CutSmart Buffer	2 μl	5 μl
ddH2O	Up to 20 μl	Up to 50 μl
Digestion at 37℃ for 2.5hr.

Confirm the size of the digested product by gel electrophoresis.
Gel purification of the target size.
Ligation

Vector (2 kbp)	molar ratio = 1:3 (can up to 1:10 depending on the DNA sizes)
Insert (1.5 kbp)
Quick Ligase Reaction Buffer (2X)*	10 μl
Quick Ligase	1 μl
ddH2O	Up to 20 μl

Transform the product by heat shock.

PCR Clean-Up & Gel Extraction

Gel Dissociation

Gel Extraction

Excised the DNA fragment from the agarose gel.
Transferred up to 300 mg of the gel slice to a 1.5 ml microcentrifuge tube.
Added 500 μl of the Gel/PCR Bufffer to the sample and mixed by vortex.
Incubate at 55~60℃ for 10 minutes (or until the gel slice has completely dissolved).
During the incubation, mixed by vortexing the tube every 2~3 minutes.
Cooled the dissolved sample mixture to the room temperature.

DNA Binding

Placed a PG Column in a Collection Tube. Apply the supernatant to the PG Column by decanting or pipetting.
Centrifuged at 16,000 xg for 30 seconds.
Discarded the flow-through and place the PG Column back into the same collection tube.

Wash

Added 400 μl of the Buffer W1 into the PG Column.
Centrifuged at 16,000 xg for 30 seconds.
Discarded the flow-through and place the PG Column back into the same collection tube.
Added 600 μl of the Buffer W2 (ethanol added) into the PG Column.
Centrifuged at 16,000 xg for 30 seconds.
Discarded the flow-through and place the PG Column back into the same collection tube.
Centrifuged at 16,000 xg again for 2 minutes to remove the residual Buffer W2.

Elution

To elute the DNA, placed the PG Column in a clean 1.5 ml microcentrifuge tube.

Competent Cell Preparation

For E. coli DH5α,BL21(DE3) and W3100(DE3) competent cell

Streak out wild type E. coli on a plate (LB plate without antibiotics) overnight and pick one colony into 3 ml of media (LB) and grow overnight.
Transfer 0.4 ml of starter culture into 40 ml of fresh LB and grow culture at 37 ℃.
When the OD600 nm up to 0.35, put the cells on ice immediately.
Spin the cells at 4℃for 10 minutes at 4000 rpm.
Suspend the pellet on ice carefully with 16 ml chilly Transformation Buffer 1(TFB1).
Leave nicely suspended bugs on ice for 10 minutes.
Spin the cells at 4℃ for 10 min. at 4000 rpm.
Suspend the pellet on ice with 1.6 ml of Transformation Buffer 2 (TFB2).
Leave on immediately on ice for 30 minutes.
Aliquot 100 μl into 1.5 ml centrifuge tubes and snap freeze immediately with liquid nitrogen.
Store the frozen cells in the -80℃ freezer.

Plasmid Extraction

1. Transfer 1.4 ml of well-grown bacterial culture to a centrifuge tube.

2. Centrifuge the tube at 16,000 xg for 1 minute to pellet the cells and discard the supernatant completely.

3. Add 200 µl of FAPD1 Buffer (RNaseA added) to the cell pellet and resuspend the cells completely by pipetting.

･ Make sure that RNaseA has been added into FAPD1 Buffer when first use.

･ No cell pellet should be visible after resuspension of the cells.

4. Add 200 µl of FAPD2 Buffer and gently invert the tube 5 ~ 10 times. Incubate the sample mixture at room temperature for 2 ~ 5 minutes to lyse the cells.

･ Do not vortex, vortex may shear genomic DNA. If necessary, continue inverting the tube until the lysate become clear.

･ Make sure the tube transfer to clarify from turbid

･ Do not proceed with the incubation over 5 minutes.

5. Add 300 µl of FAPD3 Buffer and invert the tube 5 ~ 10 times immediately to neutralize the lysate.

･ Invert immediately after adding FAPD3 Buffer will avoid asymmetric precipitation.

6. Centrifuge at 16,000 xg for 3 minutess. to clarify the lysate. During centrifugation, place a FAPD Column in a Collection Tube.

7. Transfer the supernatant carefully to the FAPD Column and centrifuge at 16,000 xg for 1 minute. Discard the flow-through and place the column back to the Collection Tube.

･ Do not transfer any white pellet into the column.

8. Add 400 µl of W1 Buffer to the FAPD Column and centrifuge at 16,000 xg for 1 minute. Discard the flow-through and place the column back to the Collection Tube.

9. Add 600 µl of Wash Buffer to the FAPD Column and centrifuge at 16,000 xg for 1 minute. Discard the flow-through and place the column back to the Collection Tube.

･ Make sure that ethanol (96 ~ 100 %) has been added into Wash Buffer when first use.

10. Centrifuge at 16,000 xg for an additional 3 minutes to dry the FAPD Column.

･ Important step! The residual liquid should be removed thoroughly on this step.

11. Place the FAPD Column to a new 1.5 ml microcentrifuge tube.

12. Add 30 µl of Elution Buffer or ddH2O to the membrane center of the FAPD Column. Stand the column for 3 minute.

･ Important step! For effective elution, make sure that the elution solution is dispensed on the membrane center and is absorbed completely.

･ Do not elute the DNA using less than suggested volume (50 µl). It will lower the final yield.

13. Centrifuge at 16,000 xg for 3 minute to elute plasmid DNA and store the DNA at -20 ℃.

DNS reductive sugar measurement

DNS solution preparation:

1. Disolve 2.5g of 3,5-Dinitrosalicylic acid (DNS) to 150ml double distilled water.

2. Heat to solution to 45 degree Celsius and add 4g of NaOH. Stir the solution until it is transparent.

3. Add 75g of potassium sodium tartrate and add water to 250 ml.

4. Keep the solution without light exposure. The solution can be used after 7 days.

Principle:

Under base solution, DNS will turn to brown color while reacting with reductive sugar in high temperature. In the specific temperature range, the color will have linear relationship with the reductive sugar concentration.

Calibration:

1. Prepare glucose or xylose water solution to the following concentration: 0, 0.2, 0.4, 0.8, 1.0, 1.2, 1.6, 2 g/L

2. Take 200 ul of sample, add 200 ul of DNS solution.

3. Heat the sample at 100 degree Celsius for 10mins.

4. Cool down the sample with ice to room temperature.

5. Measure the optical density of the sample with 540nm light wavelength.

6. Draw the graph of sugar concentration with respect to optical density.

Calibration results:

Measurement:

1. Take 200 ul of sample, add 200 ul of DNS solution.

2. Heat the sample at 100 degree Celsius for 10mins.

3. Cool down the sample with ice to room temperature.

4. Measure the optical density of the sample with 540nm light wavelength.

5. Get the concentration of reductive sugar from the Calibration graph.