Various questions about Silver stain

Dr Engelbert Buxbaum engelbert_buxbaum at hotmail.com
Fri Mar 12 13:19:52 EST 2004


Fabius wrote:

> I use Silver Stain for RNa and DNA in Polyacrylamide Gels and in Agarose
> gel.
> In  the Polyacrylamide gels i use  the "Merril" methods (Science, vol.
> 211,1427-1428, 27 march 1981) that was write for Proteins

At least with proteins I get better results with the method of
Heukeshoven & Dernik


> Besides I use Ethanol instead of methanol only becouse is more cheap and
> less toxic, but i don't know why Merril instead suggest methanol (Why
> methanol?).

Ethanol is heavily taxed in many countries and thus often 10 times the
price of methanol. Other than that, you can use methanol, ethanol and
iso-propanol pretty much interchangeably.

> Often the stain is more yellow than black, why? Do it hit with ethanol?

Again with proteins you get different colours (yellow, brown, red,
black) depending on the protein composition. It seems to depend on the
size of the silver grains formed. This again depends on the proteins,
the staining method used, temperature.... Silver staining always was
more art than science.


> I've read too that is possible to drying the gels with cellophane sheets,
> but it's not clear if i can do this (withaut new machine )

You do not need a machine at all. The gel is equilibrated with 10%
glycerol and placed between two sheets of cellophane soaked in the same
solution (no airbubbles!). The sandwich is mounted between two plastic
frames which are clamed together with clips (those black metal things
used in the dark room, about 3 on each side of the frame). All the
frames do is prevent the sandwich from wrinkling during drying. You can
buy the frames, but they cost a fortune. Better to have your workshop
cut them from PVC, perspex or the like (2-3 mm thick). They should be
about 2 cm wide, and slightly smaller than the cellophane sheets you
plan to use. Just leave upright over night, than cut out the gel from
the excess cellophane around it.


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