No more wedge gels?

ww40 William_D_WARREN at UMAIL.UMD.EDU
Fri Jun 5 14:32:00 EST 1992

John Nash writes...

>I have been using an alternative to wedge gels that saves acrylamide,
[stuff deleted]
>Run the gel with 0.5X TBE in the top tank and normal 1 X TBE in the
>bottom tank.  Just after the last (or in the case of one load - the
>only) load has run into the gel, put a half volume of 3 M sodium
>acetate in the bottom tank (make sure you leave enough room - I use
>300 ml 1 X TBE and 150 ml 3 M Na acetate in my BRL S2 gel box).
>This causes a themal gradient across the gel - the bottom is
>relatively cool and the top gets quite hot to touch.  This causes the
>bands to run closer at the bottom.

I also use this procedure and find it heaps easier than fiddling
with gradient gels or wedge spacers - My only comments are that I
usually put 1xTBE in the gel, top tank and bottom tank. Also I was
under the impression that the acetate addition created a buffer
gradient, slowing the migration of the bands low in the gel due
to the extra ions migrating into the gel. I guess that this
would produce a temperature differential as well (I never noticed
it) - But which is cause and which is effect ???

Does anyone have another opion on this or can clear up my
(or John's) misconceptions ???

Bill Warren
Ctr. Ag. Biotech.
University of Maryland

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