Boiling ethidium bromide gel

Vladimir Svetlov svetlov at
Tue Apr 28 16:17:59 EST 1998

In article <6i437i$24t at>,
un691cs at wrote:

> >A good practice is to use a separate microwave for this and reheating food.
> generally, I wouldn't use ANY laboratory instrument for 'dinner' purposes....
> and not just because it is illegal. You never know what your colleague  
> has been doing witht he microwave...

"Generally" is a good word. I would not think - untill I saw it done - that
people would use a hot plate/stirrer to make noodles or heat up stripping
solutions in the same microwave others use to warm up lunches... Unless
there are two microwaves in the lab - one of them in the lunch room -
people would cook agarose and sandwiches in the same one. Ye know, after i
found a frozen Tyson chicken in the -80 C freezer next to frozen calf
thymus, yeast, E. coli and Salmolnella cell masses I ain't taking any
chances with people's common sense. 

 > >I'm not sure that anybody actually studied it but it's a good idea to keep
 > >food away from the hazardous chemicals anyway. Recently I've taken up
 > >adding EtBr to the loading buffer instead of the gel - far less EtBr to
 > >worry about (in the running buffer etc.), lower background and you can boil
 > >the agarose as much as you want.
> Different froms of DNA, like circular vs. linear migrate differently 
> in the presence or absence of EtBr. My advice is to run agarose
> gels without EtBr, and then stain them for 5' afterwards. IMH, this gives the
> nicest results.

Depending on the thickness of the gel staining and destaining may take up
far longer than 5'. And of course I was not talking about application
(absent from my own cloning work) that require separation of different
helical forms of DNA. So as an alternative to having lotsa EtBr in the gel
(and eventually in the running buffer or staining/destaining solutions)
adding it in smaller amounts to the DNA is not so bad. 

Vladimir Svetlov, Ph. D.
McArdle Lab for Cancer Research
Dept. Oncology
1400 University Ave.
Madison, WI 53706

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