Question on Liquid vs. Solid Media with Invitrogen's TOPO-10 bacteria!

Jeff E. Janes jejanes at
Thu Jul 9 18:02:52 EST 1998

David Kong wrote:
> Hello,
>  I'm a summer student at a local molecular biology lab and I was
> wondering whether anyone else was having difficulty growing colonies up
> in LB liquid medium, in comparison to LB--agar medium (both with 50ug/ml
> ampicillin).  I also attempted to grow up the colonies in SOC medium
> (50ug/ml ampicillin), SOC medium (50ug/ml kanamycin) - which
> incidentally yielded one successful culture, it was the control clone
> however.
>   Having altered the antibiotic and the medium type I'm at a loss for
> why I can't get growth from the liquid medium; whereas on LB-agar plates
> (50ug/ml) [my colony source], growth did occur.  I'm using Invitrogen's
> TOPO-10 bacteria from the TOPO-TA "Five Minute Cloning" kit).
>   Does *anyone* have any suggestions???
>   One other question.. just how sensitive is the TOPO-10 bacteria to
> heat and pH? (I'm speaking of a difference of a degree, and a difference
> in pH by 1.0 in the LB solution).
>   I am quite new to this, and if anyone can shed some light on my
> problem, I'd be forever grateful!
> Thanks in advance,
> Dave

What plasmid is in the E. coli?  Does it have a protein expression
system?  I have seen cases of bacteria
growing on LB-Amp plates but not in LB-Amp culture when using either
arabinose or T7 promoters.  Adding glucose to the media shuts down
the promoter and gives growth in liquid media.


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