Low concentration miniprep

shifali chatrath via methods%40net.bio.net (by shifalich from rediffmail.com)
Fri Jan 23 04:59:34 EST 2009


  
Dear all!
Thankyou very much for prividing me wealthy info on satellite colonies.
Shifali

On Mon, 19 Jan 2009 Duncan Clark wrote :
>Historians believe that in newspost <mailman.1461.1232227543.29717.methods from net.bio.net> on Sat, 17 Jan 2009, shifali  chatrath <shifalich from rediffmail.com> penned the following literary masterpiece:
>>  Just a query! Are satellite colonies correctly defined as slow growing colonies or a daugther colony of nearby parent colony?
>
>
>Neither.
>
>Satellite colonies arise on electroporated/transformed E.coli ampicillin plates when the ampicillin resistant colony's beta lactamase destroys ampicillin in the vicinity of that colony. As there is now no ampicillin in the media around that colony, background non-plasmid plated E.coli cells start to grow, giving rise to so-called satellite colonies.
>
>It doesn't happen with a kanamycin as the antibiotic is not destroyed.
>
>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.
>
>Duncan
>-- I love deadlines. I especially like the whooshing noise they make as
>they go flying by.
>
>Duncan Clark
>GeneSys Ltd.
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Shifali Chatrath
Graduate Student
Protein science Lab
Dept. of Biological sciences
National University of Singapore
Singapore
+65-65161210
+65-96393449


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