Hoefer HE99X - Manual (Page 23)

place the gel on the transilluminator, ensure that
it lies flat by cutting off the ridges formed by the
grooves in the running tray. (Do not damage the
transilluminator surface; trim both ends of the
gel with a spatula while it is still in the tray, lift
away the ridges, and then slide the gel onto the
transilluminator.) For viewing, 302 nm light is
recommended for both acceptable sensitivity and
reduced photonicking.
To reduce the background fluorescence of
unbound ethidium bromide, the gel can be
destained by soaking it for 5 minutes in 0.01
M MgCl
2
, or for 1 hour in 0.001 M MgSO
4
.
Destaining makes it easier to detect small quan-
tities (less than 10 ng) of DNA. (Sambrook and
Russell, A9.4.).
Transfer
Before transfer, trim off the ridges at both
ends of the gel to ensure even gel contact with
the membrane.
Bibliography
Ausubel, et al., (eds). Current Protocols in
Molecular Biology. Greene Publishing and
Wiley-Interscience. New York (1993).
Sambrook, J., and Russell, D.W., Molecular
Cloning: A Laboratory Manual. Cold Spring
Harbor Laboratory Press. (2001).
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