Electrophoresis Gel?

Chromosome Terror abrdlher at reading.ac.uk
Fri Feb 24 10:03:31 EST 1995



On 24 Feb 1995, Jim Fegan wrote:

> 	My Biotechnology class has divided up into small teaching 
> groups, so we can go to various middle schools and show them how to 
> properly execute the electrophoresis (sorry about spelling) 
> lab.  
> 	Our teacher is running on a short budget though, and she is 
> reluctant about the use of agarose gel because of it's cost.  Our lab 
> group was looking for a possible alternative to the agarose.  Our ideas 
> were few, and we even tried geletine, but it ended up melting under the 
> current.  
> 	Does anyone know of a gel that would provide a suitable matrix 
> for the electrophoresis?  If you could email me any suggestions you 
> might have, I would greatly appreciate it.
> 
> Thank you in advance,
> Jim
> fegan1 at ix.netcom.com
> 	
> 
> 
As far as I know, if you want to do DNA separation, you'll have to use 
agarose for a decent result. 
There are different grades, of course, and you might not need the purest.
Also there's the agarose concentration.
I used 0.6% gels when I was separating pBluescript inserts (600 to 4000bp).
Also, you can do some nice 'trick'. Well, it's not much of a trick, but 
when I first saw it I was amazed! 
The 'trick' is preparing a gel over a glass plate. Pour the molten 
agarose carefuly onto the plate, as to form a thin gel, held only by 
surface tension... probably about 3mm deep. The comb will have to be put 
in place previously very carefully, as to avoid touching the bottom, but 
leaving as small a gap as possible. How much agarose? Try... I used 
minigels with plates about 6cm x 10cm and I could pour in about 23ml of 
0.6% agarose easily. Be careful pouring, but firm and quick, because it 
sets so quickly... 
You'll need less agarose. The gels will be prepared much more quickly. 
Being so fine, the amount of DNA needed for detection after Et-Br 
staining is smaller too... and it runs quickly!
It's a bit fiddly to start with, but I found I could say "mmm, I'd like 
to run a gel right now..." and in an hour I'd have the result!
(of course, use as little buffer as possible for fast runs (1xTBE for 
me), and if the plate is not as wide as the gel tank, put something at 
the sides of the plate to reduce the volume of buffer... but watch out, 
if you set it too high it might melt!... I used 75mA ok... runs of 30'... 
it warms up noticeably, but it's ok)

Sorry I got a bit carried away... I hope you can find any of this useful...

Nacho.




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