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DAPI Stain

Helen McBride helen.mcbride at genetics.utah.edu
Tue Aug 5 17:28:15 EST 1997

     Are you sure that you can see both DAPI and GFP at the same time on
your microscope? Most multicube filters will not let you see both DAPI
and GFP at the same time as DAPI's emission overlaps with the GFP
excitation wavelength. That means that you don't excite the GFP, and what
you'll see is DAPI looking great, GFP on the FITC channel, but no GFP on
the mulicube. 
     You can use a red-shifted GFP to get around this problem, but you
should carefully compare the excitation/emission wavelengths to the
parameters given on your multicube to make sure that you won't have
overlap. The other alternative is to buy one of the DNA stains that
Molecular Probes sells which is out in the rhodamine region of the
     You could also try different fixation methods if you feel that the
scope is not the problem. You can try combinations of
formladehyde/glutaraldehyde ratios. Most of those parameters are
discussed in any good fluorescence microscopy book. Good luck to you.
Helen McBride
University of Utah 
Grad Student
Dept. of Onc. Sci.
helen.mcbride at genetics.utah.edu

"Where the telescope ends, the microscope begins, which of the two has
the grander view?" Victor Hugo

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