Blue/white colony selection problems

eb86336 at eb86336 at
Mon Sep 12 18:21:04 EST 1994


These sound like satellite colonies.  Satellite colonys are small colonies that
grow around colonys that contain cells that are true transformants of Amp
resistant plasmids.  Beta-lactamase (the Amp resistance protein) is secreted
outside the E. coli cells.  This enzyme then act to detoxify a small area
around the transformed cell allowing cells that are not truly transformed to
grow around it - these are satellite colonies.  If you were to pick these small
colonies and patch them onto a fresh Amp plate, they will not grow.

Mike Menke
Eli Lilly and Company

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