Competent BL21 strains- preferred method anyone ?

Christopher W Kafer ckafer at
Wed Nov 7 21:34:38 EST 2001

I also use the Inoue method or the single step method of Chung 
(Current/short protocols). BL21 always transforms poorly.  BL21 Gold 
strains from Stratagene (?) give higher efficiencies.  It's usually not a 
problem to have lower efficiencies though since you dont use that strain 
for cloning etc., no?

Moreland Gibbs <moreland.gibbs at> wrote in 
news:B80FFF5C.6F5%moreland.gibbs at

> I am trying to make competent BL-21 derived strains.  Our usual preferred
> method for chemically competent cells is giving efficiencies of only
> 10^4-10^5/microgram DNA (Inoue method).  I have also tried the method of
> Nishimura which also worked poorly. Next I will try electroporation but
> would like to ask...

More information about the Methods mailing list