Help on Transilluminators

Ned Mantei mantei at
Sat Sep 30 02:19:06 EST 1995

In article <44hemt$o9l at>, Javier Quintero Vazquez
<bnjquint at> wrote:

> Hi.
> I need information about the correct selection of a transilluminator, the 
> main use will be for visulization of agarose DNA gels stained with 
> ethidium bromide.

If you are going to be running *preparative* gels, look at BioTechniques
11:747-748 before you buy.  Irradiation  with 302 nm UV will inactivate
your plasmid DNA (measured as number of colonies upon transfection) with a
half-time of less than 60 seconds, depending on size of the plasmid. A
wavelength of 254 nm is even worse. By the time you have cut out your
vector band, you may have inactivated 99% of the biological activity.
With 366 nm wavelength, there was no noticeable loss of activity within 3
minutes. The sensitivity of detection with 366 nm light *might* be less,
with the minimal detectable amount of DNA in a band being perhaps 5 ng
instead of 3 ng with shorter wavelength light.
If you are buying just one transilluminator for all uses, I would
recommend 366 nm.

Ned Mantei
Neurobiology, Swiss Federal Institute of Technology
CH-8093 Zurich, Switzerland
mantei at; fax: +41-1-633-1046

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