HELP! -- Protecting DNA on a transilluminator?

Klaus Salger salger at
Mon Jul 7 14:15:37 EST 1997

Vern Shellman (Vern.Shellman at UCHSC.Edu) wrote:
: I am having problems ligating my DNA fragments cut out of a gel.  I
: get variable results that seem to relate  to how long it takes to cut
: out the band.  The fastest I can see and cut out a band is about 15
: seconds and by then I suspect there is already significant UV damage.
: Is there any way to protect my DNA during UV exposure?


I think the best thing to do is to use a relatively long wave length. As far
as I remember there was a paper in BioTechniques comparing the cloning
efficiencies of fragments that have been exposed to different wave length
UV. Using 360nm UV is far better than the usual shorter wave lengths.

If you don't want to buy new bulbs you could decrease the UV dose e.g. by
placing your gel on a normal glas plate for cutting. This will result in
just a little portion of UV reaching the DNA. Enough to see the band but not
too much. So DNA damages are reduced.

Hope this helps

Klaus Salger		phone : +49 (0)89 5902 	-502
Zoologisches Institut	FAX   :			-450
AG Wetterauer		e-mail: salger at
Luisenstr. 14
80333 Muenchen


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