Quantitating DNA or RNA?

paul lacy lacyp at unicorn.it.wsu.edu
Mon Nov 3 18:09:33 EST 1997

Martin Offterdinger (a8803349 at unet.univie.ac.at) wrote:
: On Sun, 2 Nov 1997 19:06:11 GMT, Harry Witchel
: <Harry.Witchel at Bristol.ac.Uk> wrote:

: >Hi folks --
: >    I am looking for a relatively quick (but not necessarily cheap)
: >method for quantitating the amount of DNA or RNA in a 1 ul sample.
: >Currently I use gel electrophoresis which is a bit too slow and does not
: >detect below 10 ng (in my hands), and gel electrophoresis is useless for
: >mRNA quantitation.  I have in the past tried spotting DNA on to agarose
: >with Ethidium Bromide and making Ethidium bromide spots on saran wrap
: >(Maniatis protocols), and I unfortunately found that in my hands all I
: >could tell is whether there was more than 100 ng in the sample --
: >background seemed quite high.
: >    Thanks in advance,
: >        Harry
: >
: Molecular probes sells a compound known as sybro green - they claim
: that it is more sensitive than ethidium bromide and less mutagenic -
: have never tried it personally.
: Martin

If this is the same as the Syber-Green II dye (from Promega?), it does
work pretty well.  Gives a much lower background in a gel than ethidium
bromide.  You do need a different color filter for the camera than you use
for ethidium bromide.  Also, the dye seems to break down in the gel 
within 10 minutes or so of exposure to room lighting, so you have to
keep it covered up.

Paul Lacy
lacyp at wsnix.wsu.edu

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