BL21(DE3) pLYSe/s competent cells

Paul A Bucciaglia bucci001 at
Fri Nov 15 12:11:59 EST 1996

I remember a decrease in competancy.  As the post below states, usually 
your just moving gobs of plasmid DNA to a different host.  However I have 
found that decent comp cells (>10EE6/ug pUC), stored frozen, will work.

ashaw5 at writes:

>Who cares?  We freeze our BL21/lysS homemade competents and yes the
>efficiency is poor.  (Now I think I know the reason).  But you are
>generally transferring a plasmid into BL21 from another bug and so you
>don't need very efficient bugs.  100ng should easily give you enough
>colonies even if your efficiency is 10-3.

>Andrey Shaw

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