I've had this problem, but always believed it was in the nature of
XL1-blues to be slow growing. Although XL1-blues are supposed to have a
higher transformation efficiency than some other lines, I use DH5 alpha
whenever possible because they grow faster. When I need the color selection
of the blues, I usually have to leave the plate on my bench all day (25C)
after the initial over-night 37C incubation in order to see the blue color.
Of course, maybe we're both doing the same thing wrong to make them grow slowly.
Dept. of Biological Sciences
Univ. of Pittsburgh
In Article <1994Jul27.213302.1 at aurora.alaska.edu>, fsajb3 at aurora.alaska.edu
>Anyone have experience with this problem?
> Our lab has been transforming XL1-blue chem comp cells (made competent
>in our lab using FSB protocol) with various pBSIIKS constructs. There has
>been no problem getting transformants, but the colonies grow extremely slow,
>and there is a really long delay before any blue color develops for blue/white
>selection. I checked to make sure we weren't overdosing the plates with
>ampicillin, everthing seemed normal. We are using bluo-gal and 100mM IPTG for
>color selection. Any information is greatly appreciated.