Ned Mantei mantei at neuro.biol.ethz.ch
Thu Aug 29 03:49:20 EST 1996

In article <32249E26.67C6 at midplains.com>, Les Hoffman
<lhoffman at midplains.com> wrote:

 Yes-- long- (305-315 nm) or
> shortwave (260 nm) UV transilluminators can cause the formation of
> cyclobutane pyrimidine dimers (CPD's) in adjacent pyrimidine residues of
> DNA. But no-- there is not normally "breakage" of the DNA by UV light
> alone.
...... We run an adjacent pair of marker lanes containing the same
> DNA sample, cut out the "prep" lane to be cloned without UV exposure, and
> mark the positon of the desired band(s) in the marker lanes with a blunt
> pencil tip during UV transillumination.

We just use a UV table with 365 nm UV. 
Incidentally, there was a comparison of 365 vs. 302 nm lamps in
BioTechniques 11:747-748 (1991). With 302 nm the transfectability of your
plasmid DNA can drop to less than 1% within a minute or two (depends on
vector size)!

Ned Mantei
Dept. of Neurobiology, Swiss Federal Institute of Technology
CH-8093 Zurich, Switzerland
mantei at neuro.biol.ethz.ch   Fax: +41-1-633-1046

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