Team:LMU-Munich/Notebook/Protocols/7 Measurement of competence

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Source:http://partsregistry.org/Help:Protocols/Competent_Cells

Transform 50 μl of cells with 1 μl of standard pUC19 plasmid (Invitrogen)
- This is at 10 pg/μl or 10^-5 μg/μl
- This can be made by diluting 1 μl of NEB pUC19 plasmid (1 μg/μl, NEB part number N3401S) into 100 ml of TE
Hold on ice 0.5 hours
Heat shock 60 sec at 42C
Add 250 μl SOC
Incubate at 37 C for 1 hour in 2 ml centrifuge tubes rotated
- using 2ml centrifuge tubes for transformation and regrowth works well because the small volumes flow well when rotated, increasing aeration.
- For our plasmids (pSB1AC3, pSB1AT3) which are chloramphenicol and tetracycline resistant, we find growing for 2 hours yields many more colonies
- Ampicillin and kanamycin appear to do fine with 1 hour growth
Plate 20 μl on AMP plates using sterile 3.5 mm glass beads
- Good cells should yield around 100 - 400 colonies
- Transformation efficiency is (dilution factor=15) x colony count x 10⁵/µgDNA
- We expect that the transformation efficiency should be between 5x10⁸ and 5x10⁹ cfu/µgDNA

@@ Line 7: / Line 7: @@
 * Hold on ice 0.5 hours
 * Heat shock 60 sec at 42C
-* Add 250 &mu;l [[SOC]]
+* Add 250 &mu;l [[Team:LMU-Munich/Notebook/Protocols/8_SOC_medium|SOC]]
 * Incubate at 37 C for 1 hour in 2 ml centrifuge tubes rotated
 ** using 2ml centrifuge tubes for transformation and regrowth works well because the small volumes flow well when rotated, increasing aeration.