Culture of E.Coli (SURE) / Large Plasmids / Foreign Sequences

Joan Shields joan at
Mon Apr 1 15:34:20 EST 1996

Dr Alexander J Annala <ucklw08 at> wrote:
>Sambrook/Frisch/Maniatis Molecular Cloning page 1.21 suggests that
>where plasmids grow poorly because of their large size or because of
>foreign sequences they carry it may be worthwhile to consider some
>alternative ways to grow and treat a bacterial culture.  Presumably
>this means alternative ways not included in the discussion which is
>immediately above on the same page about chloramphenicol treatment.

>What alternative ways to grow and treat the bacterial culture should
>be considered in the instant situation?

Well, I've always found that there are a couple of things I can do to help
a culture along.  You can grow a 5mL culture the night before and use that
to inoculate a larger culture.  You can also use a larger flask to grow
your culture - gets better aeration that way.  If those don't work (do
both) then you can think about enriching your media and trying the above
again.  I wouldn't leave out the antibiotics as you don't want to
encourage competing bacteria (non-transformed).  You might also want to be
sure that you're not leaving something important out of your media.  


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