Mon Jul 29 21:30:38 EST 1991

Bill Melchior asks for a safer method for staining DNA bands in
agarose gel, as an experimental protocol for high school teaching.

We in Singapore have been doing Biotechnology Workshops for
School Teachers to help them device practicals for the school curriculum
for the past two years.
As far as staining agarose gels is concerned, we have been showing the
teachers ethidium bromide staining and UV illumination. Now that
you have mentioned the safety hazards involved especially with school
pupils, perhaps, I should look into exploring alternatives.

One safer alternative, according to Berger and Kimmel, Meths Enzymol
Vol 152. or Guide to Molecular Cloning Techniques, Academic Press, 1987
page 71. is methylene blue dye as you suggested.  It avoids EthBr and UV.

1.Stain in 0.02% methylene blue, 10mM Tris Acetate pH 8.3 for 1-2 h 4 deg C

2.Wash off excess stain with several changes of water over 5-8 h.

3. Limit of detectability is quoted at 250ng/1 cm band.

A colleague says it works fine, other than the low sensitivity and it
is useful for preparative purposes.

Dept of Biochemistry, National University of Singapore, Kent Ridge, SINGAPORE
(which is NOT in Japan, as one correspondent from USA was tempted to append
at the bottom of the address label in a recent airmail letter.)

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