large DNA plasmid prep

[CHMC]

Lakshman Ramamurthy PhD <lr50916 at glaxowellcome.com> wrote in article
<3454FD2D.14D at glaxowellcome.com>...
> Netters:
> 
> I have tried unsuccessfully to make a Qiagen large prep of a 23 kb
> plasmid DNA.. Do you have any suggestions to get around this problem. I
> need about 100 micrograms of DNA
> Thanks
> LR
> 
I have a 85 kb plasmid that I often have to isolate, and the Qiagen maxi
preps are about the only way I can ever get any.  My bacteria makes a lot
of capsule, so I grow it to mid log phase instead of using overnight
cultures, and I have to use double the normal volume of the first three
solutions.  It also helps if I spin down the lysed cells in a oversized
bottle, which seems to help keep the plasmid from getting trapped in the
goo and dragged down with the proteins.

Adam Griffith