Gels keep cracking

theodorn at medlib.georgetown.edu theodorn at medlib.georgetown.edu
Mon Nov 30 11:44:10 EST 1998


In article <pxpst2-2811981254120001 at pelli.pathology.pitt.edu>,
  pxpst2 at unixs.cis.pitt.edu (Peter) wrote:
> I routinely dry my 14% gels with about a 10% cracking frequency.  My
> samples use I125 as the label source.  I do not fix the gels and I do not
> use glycerol.  But if you can get rid of the fixing step and dry the gel
> immediately following the run you may have more success.  The required
> amplification may not be needed if you look for a "specialty film that is
> more tuned toward S35.
>   I dry my gels with a uniform heting of the gels for 2 hrs @ 80 C under a
> vacuum. Be careful not to strech the gel when laying it down on the filter
> paper. I usually lay the gel on the filter paper from the bottom to the
> top of the gel because the remenant stacker layer is really sticky and can
> cause the gel to elongate at the corners.
> Hope this helps
> Peter
>
> In article <v01510100630b6350aaa4@[132.234.31.46]>, S.Mckay at sct.gu.edu.au
> (S. McKay) wrote:
>
> > Hi,
> >
> >         I've been having some problems drying mini-gels.  I'm using 14%
> > SDS-PAG to separate my protein (which is 35S-labelled).  Following this I
> > have been fixing the gels in 7% Acetic Acid for 20', rinsing in dH2O and
> > then an amplification step using 0.5M Salicylic Acid for 20'.  The gels are
> > then dried onto Whatmans 3mm Chromatography Paper under vaccum and heat on
> > a BioRad Gel Slab Dryer for 1.5hrs.  Less time than this and the centre of
> > the gels do not dry.  Unfortunately, I've been experiencing severe cracking
> > problems with the gels which is obviously unacceptable.
> >
> >         I am aware that the salicylic acid will remove much of the moisture
> > from the gel but 1.5hrs seems a long time.
> >
> >         I've also tried  using the 0.5M Salicylic Acid combined with 2%
> > glycerol but this makes no difference and if anything the cracking is
> > worse.
>

It's funny, but when I used to do a lot of metabolic labelling experiments, I
used good old PPO/DMSO, which seems to be out of fashion these days, but I
never had a gel break on the dryer (even 15% gels). They seem pretty tough
after the PPO is precipitated into the gel; you can pretty much throw them
around.

Nick Theodorakis

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