In article <cx3M3.37467$Hb3.305617 at news.total.net>, Agata Klebucki
<agatakl at total.net> writes
>It might sound stupid, but how do I calculate the transformation efficiency
>of Escherichia coli with a plasmid. Any help would be greatly appreciated.
Transformation efficiency is y colonies obtained per ug of plasmid.
So transform 1ng and plate 1/10 of the cells transformed. You get say
500 colonies.
Therefore transformation efficiency is 1000g/1ng x 10/1 x 500 i.e.
5x10E6 colonies per ug.
Extra competent E.coli will give say 10E8, average Calcium chloride
preps maybe 10E6. Cut/re-ligated plasmid about 1/100 - 1/1000 of uncut
supercoiled plasmid.
Duncan
--
The problem with being on the cutting edge is that you occasionally get
sliced from time to time....
Duncan Clark
DNAmp Ltd.
Tel: +44(0)1252376288
FAX: +44(0)8701640382
http://www.dnamp.comhttp://www.genesys.demon.co.uk
