Difference between two cell strain

[Chris Fields]

Give him a break.  I think he means F', not F+.  You would know this if
you checked out the link.

ChenHA wrote:
> 
> Ashok Aiyar wrote:
> 
> > On Sat, 27 Nov 1999 12:46:15 +0800,
> >     Terry Lau (tcklau at hotmail.com) wrote:
> > >Hi,
> > >
> > >Does anyone know the difference between XL1-Blue and XL1-Blue-MR???
> > >
> > >Thanks in advance!
> > >
> >
> > The genotypes are available on Stratagene's website.  An appropriate
> > URL would be http://www.stratagene.com/manuals/200294.pdf
> >
> > Briefly, XL1-Blue is F-positive, while XL1-Blue-MR lacks mcrABC, mrr,
> > and is also F-negative.
> >
> 
> Where did you get the idea that XL1-Blue is F-positive?  As far as I
> know, most (if not all) commonly used cloning strains must be
> F-negative.  You safety officer would have a fit if he or she knows that
> you are using a F-positive strain for cloning.
> 
> >
> > Ashok
> > --
> > Ashok Aiyar
> > Department of Microbiology-Immunology
> > Northwestern University Medical School

-- 
C. J. Fields
Dept. of Biological Sciences
The University of North Texas
Denton, TX