Amp satellites

Duncan Clark Duncan at genesys.demon.co.uk
Mon Jul 18 05:45:11 EST 1994


In article: <aquilla.1124680349C at sadye.emba.uvm.edu>  aquilla at salus.med.uvm.edu (Tracy Aquilla) writes:

> First, if you use carbenicillin, you should have less of a problem, as this
> antibiotic is inactivated more slowly than AMP. Secondly, what host strains
> do you use, and what medium. Media with glucose will allow the formation of
> satellites. Thirdly, if the competent cells you use have been downshifted
> from rich medium just prior to making them competent, this problem will
> occur quite frequently. Hope this helps some.


Stratagene recommend using 80ug/ml methicillin plus 20ug/ml ampicillin. 
I assume methicillin like carbenicillin is inactivated slower than 
Amp. It is also much cheaper than carbenicillin. 

Alternatively use vectors with Cat or Kan. We never use Amp vectors 
for anything that needs overexpressing/growing in a fermenter. Kan is 
much nicer 'cos we can at least have 99.99% of our innoculum with 
the plasmid. For really large scale we can use neomycin as a 
replacement for kan. 

Duncan  
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Duncan Clark                        | Internet:    duncan at genesys.demon.co.uk
GeneSys Ltd.                        | Compuserve:  100015.1406 at compuserve.com
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