Help! Plaques don't come up.

Andrew Wallace a.wallace at qub.ac.uk.see.signature
Thu Jun 5 07:10:39 EST 1997


> Zhong Zhao (BioChem) wrote:
> >
> > Hi.
> >
> > I am preparing filters for screening Rat Genomic Library. However, I have
> > a problem in getting good plaques on plates.
> >
> > After overnight in 37C incubator, I see nice plaques but all of them are
> > below the surface of topping agarose. The surface of the topping looks
> > very shinny. I tried to adjust the topping agarose temp and different
> > agarose and all failed.
> >
> > Since I do not see plaques on surface, I decide not to make filters since
> > there may be nothing there.
> >
> > What goes wrong here?
> >
> > Please help.
> > Thanks much.
> >
> > John.
> 

You may wish to know that we had a similar problem but have now solved
it using BBL top agar prepared as follows:

BBL-TOP agar 0.6% (for 500 ml)

5 g Trypticase Peptone (from Becton-Dickinson: Cat. No. 4311921)
2.5 g NaCl
3 g Bacto Agar (Difco)

Do not add yeast extract and do not use other types of peptone, e.g. the
bacto peptone from Difco definitely doesn't work in our hands.

Hope this is useful,

Andrew
-- 
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Andrew Wallace,Ph.D., Queens University Belfast,  N. Ireland (UK)   
a.wallace at qub.ac.uk   http://web.qub.ac.uk/bb/awpage/wallace.html   
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