Measuring Transformation Efficiency

1.PrepareLBagarplatescontaining100ug/mlampicillin.

2.Add10pg(1ul)plasmidDNA(any,butwithampicillinresistanceMarker;themarkermaybeagainstotherantibioticssuchaskanamycinbutthenyoumustrplateonkanamycin-agarplates)into50ulofthawedcompetentcells.GentlymixwithPipettetipandincubateonicefor30min.

3.Transfertoa42degwaterbathandholdfor30-90sec(dependingonthetypeoftubebeingused,thesourceofthecells,etc.).

4.Movetoicetochillfor1-2min.

5.Add250ulSOCmedium,warmto37deginawaterbath,andthenmovetoashakingincubator(lessthan225rpm)at37degfor45min.

6.Plate25-300ulontheoneormanyagarplatesandincubateat37degovernight.

7.CalculatethetransformationefficiencyastransformantsperugofplasmidDNA.

Forchemicallycompetentcells,usetheformulabelowtocalculatetransformationefficiency:

(no.ofcolonies/10pgtransformedDNA)x(10⁶pg/ug)x(300ultotaltransformationvolume/Xulplated)=(#transformants/ugplasmidDNA)