Low concentration miniprep

[Aawara Chowdhury]

In <6u1gnhFcaahfU2 from mid.individual.net>,
 Christian Praetorius <prae from gmx.net> wrote:

> Duncan Clark <blackhole from abuse.plus.com> wrote:
>
>>The use of more beta lactamase resistant antibiotics such as 
>>carbenicillin will reduce satellite formation. I still use 80:20 
>>Methicillin:ampicillin, as I have a very old large bottle of methicillin 
>>from before Sigma stopped selling it.
>
> Are cells carrying a ampicillin resistence plasmid resistent to
> carbenicillin/methicillin?

DH5a carrying pBR322/pMB15-based low-copy plasmids are resistant to 
carbenicillin (at 100 ug/ml).  I prefer carbenicillin to ampicillin 
because it is more resistant to degradation by secreted beta-lactamase,
and significantly reduces the number of satellite colonies.  Also, our
carbenicillin plates stay good in the cold room for over 6 months.

We have also used Timentin for the same purpose (it is a mixture of
a beta-lactam antibiotic - ticarcillin, and the beta-lactamase i
nhibitor clavulonic acid).  Somewhat difficult to obtain without a
prescription these days.

AC
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