Long gel dryers

Thu Oct 20 21:53:30 EST 1994

Of course, first 20 cm of long gel are not useful, because sequence is
difficult to read, but separation on the low part of the gel is much better
and allow to read at least 30% more information than on standart 40 cm gel.
All this is concerning 60 cm gel. BioRad , for ex., suggests glass plates
and apparatus for 80 cm (difficult to work with, because of big size and 
weight). But information increases together with gel length.
In that case it is a mistake to ignore upper part. Such things are important
to big sequencing projects.
Drying. The best way is to stick the gel to one of the plate with "bind-silane"
from Pharmacia but do not follow their recommendation for bind-silane treatment.
All you need is 30 mkl of "bind silane" plus 30 mkl of glacial acetic acid
in a 30 ml of water. Spread 15 ml of this solution on 60 cm glass plate.
(60cmx20cm, add more for bigger plate). Let stay 15 min. Then pour off solution
and wipe the plate, apply second portion of solution in the same way. 15 min.
Pour off the solution. Wipe plate until dry. Polish with kimwipes. Wash with
detergent as usually, rinse with ethanol and let dry. Pour the gel.
Do this treatment in a hood, otherwise bind-silane could spread everywhere
and on other plate too. Do not allow assembled plates to stay for a long time
without gel, better is to pour it in a 15 min after assembling.
After electrophoresis gel is fixed in 10% acetic acid 30 min on the plate.
Then rins with water and put for 5-10 min in water. 
Dry in oven with air flow at 80 degree C. It takes about 30 min for 60 cm gel
gel should not be sticky and has no acetic smell. Be careful with hot glass.
Use metal plate to quick cooling. X-ray film can be put right on the gel 
( inportant: cool gel), or use thin film between. For exposition cover
the plate with gel by other glass plate , clamp, and put in black tissue 
in dark cool place. 
More troubles , of course, but it is the fight for additional sequencing
Excuse me for my poor English.
Best of luck

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