EtBr usage

Ed Rybicki ED at
Mon Jun 21 04:41:55 EST 1993

> In article <1993Jun18.152949.1 at>, brennanp at writes:
> |> On EtBr,
> When running RNA on a gel we routinely add small amount of EthBr.  It
> apparently helps the RNA run.

And putting it in the wells with the RNA apparently helps stain even
better - and uses less.

> Adding EthBr to DNA can affect the running of the DNA on the
> gel and alter the sizes etc.

All true.  But irrelevant for most normal use.  I use(d) 50 ng/ml EtBr in
gels and often in running buffer too (just leave in tank for many gels).
This more than enough for sensitive detection of NAs on a UV box: you can
take photos of up to 10 sec without any destaining on a 5mm thick gel.
And so much safer in terms of AMOUNT of EtBr!  Most people use about 500x
this amount, and it is UNNECESSARY!!!

 | Ed Rybicki, PhD             |       "Lord, won't you buy me        |
 | (ed at        |                                      |
 | Dept Microbiology           |         A Mer-ce-des Benz..."        |
 | University of Cape Town     |                                      |
 | Private Bag, Rondebosch     |                                      |
 | 7700, South Africa          |           - Janis Joplin             |
 | fax: 27-21-650 4023         |                                      |

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