E. coli (Bl21DE3) lyses automatically

Dr. Duncan Clark duncan at genesys.demon.co.uk
Tue Feb 18 06:20:23 EST 1997


In article <1.5.4.16.19970217185240.0927d9d0 at chemvx.tamu.edu>, Huang Ke-
xue <khuang at CHEMVX.CHEM.TAMU.EDU> writes
>Hi, Netters,
>
>I met a serious problem recently. The transformed BL21(DE3)(by a expression
>plasmid) lyses automatically after 6-8 hr growing. I repeated this three times. 
>Do you think my stuff was contamined by Phage(?). 
>Any suggestion?
>

I bet if you put in just pUC19 it would not lyse and that your problem
is lethal expression due to the leakiness of the T7 control system in
that strain. You may be better off using the pLysE or pLysS strains as
they inhibit the trace amounts T7 pol in the lysogen and will therefore
tolerate a bit better 'lethal' clones.

Duncan 

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Dr. Duncan Clark
DNAmp Ltd.
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http://www.genesys.demon.co.uk



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