Questions about F'plasmid in male E. coli strain.

Duncan Clark Duncan at
Fri Aug 11 09:37:01 EST 1995

In article: <9508102138.AA11933 at>  yuanqiao at (Qiaoping Yuan) writes:
> I have a clone on a pUC-based vector in a male E. coli strain (has F'
> plasmid) When I extracted the plasmid DNA from this strain, I got two high copy
> number plasmids (one of them was supposed to be my clone). My questions are:
> 1. Is F'plasmid a high copy number in E. coli?

No single copy only.
> 2. What is the size of the F' plasmid (its genotype is F' traD36 proAB<+>
>    lacI<q> lacZdeltaM15)?

At least over 100kb if not 150kb. 

> 3. How can I separate these two plasmids (can I separate them by transform
>    another E.coli strain, e.g. DH5a)?

If you really have two high copy plasmids in the same cell then they have to be
different incompatbility groups. Alternatively you have a mixed culture with 
and without insert? Finally how do you know you have two plasmids and not 
multimers and/or ccc/linear/OC mix of one plasmid


My mind's made up. Don't confuse me with the facts!

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