Visible Difference

Leaf samples provided by Neal Stewart, University of North Carolina at Greensboro

Wild-type (right) and GFP-expressing (left) canola leaves viewed with the Illumatool LT-9500.

Excising bands from a gel on a UV light box can leave improperly shielded scientists looking a little crispy around the ears. Most UV users don't realize that many of the dyes and stains commonly used to visualize nucleic acids and proteins have a bimodal excitation spectrum. While the absorption peak most frequently exploited for visualization occurs in the UV range, another generally stronger peak occurs in the visible range. With the proper light source, therefore, these dyes and proteins can be excited with safe, visible light instead of hazardous UV radiation.

The Illumatool Tunable Lighting System (TLS) from Lightools Research of Encinitas, Calif., is just such a lighting system. Employing interchangeable filters, the Illumatool TLS offers wavelength control between 390 and 750 nm, 100 percent...