Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

There are not much details about the wavelengths and type of imaging you
use to excite and visualise your dyes. I know that when I excite DAPI
with my multi-photon laser the emission will also show up in the green
(>500 nm) channel. Maybe this is what you are looking at?

Gert van Cappellen

Suzana Glavas wrote:

> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
> Perhaps somebody can help me make sense of this.   We have a GFP tagged
> protein expressed in C. elegans embryos.  Since the GFP signal is not
> very
> strong, we use an anti-GFP antibody and a FITC tagged secondary to better
> see this particular protein.  When we visualize the FITC stain, we see
> nice
> membrane localized staining with very minimal background.  We then switch
> over to DAPI to look at the nuclear staining.  When we switch back to
> FITC,
> all of the nuclei can now be seen in the FITC channel.  We are
> visualizing
> with an epifluorescence system prior to doing confocal.  Any ideas what
> might be happening?
>
> Suzana Glavas


--

wigGert van Cappellen
Reproduction and Development, Erasmus MC, Tel. +31-10-40 87578 FAX +31-10-40 89461
Dr. MOlenwaterplein 50, 3015 GE ROTTERDAM, Netherlands
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http://www.eur.nl/fgg/endov/multiphoton
applied Optical Imaging Centre
http://www.eur.nl/fgg/molmed/OIC/