Not everyone knows that the product of the Feulgen reaction is fluorescent. If you do the method on paraffin sections, DNA in nuclear chromatin is red with ordinary illumination. If you look with a fluorescence microscope (blue excitation) it shows as a brownish-red fluorescence in the chromatin. A similar fluorescent colour is seen in conventional PAS-stained sections, in mucus, basement membranes, etc. You need a non-fluorescent mounting medium: DPX or one of the various poly(methyl methacrylate)-based media such as Entellan. John Kiernan Professor Emeritus, Dept of Anatomy & Cell Biology University of Western Ontario, London, Canada https://www.schulich.uwo.ca/anatomy/people/bios/emeriti/kiernan_john.html Also Secretary, Biological Stain Commission, Inc. https://biologicalstaincommission.org<https://biologicalstaincommission.org/> = = =
<https://biologicalstaincommission.org> ________________________________ From: Alida Bailleul via Histonet <histonet@lists.utsouthwestern.edu> Sent: June 3, 2021 7:53 AM To: Histonet@lists.utsouthwestern.edu <Histonet@lists.utsouthwestern.edu> Subject: [Histonet] Protocol for DAPI staining on paraffin sections Dear Histonet list, I have made some paraffin blocks of demineralized bone and cartilage. I would like to stain paraffin slides with DAPI (or another DNA stain). Does DAPI staining (or other fluorescent DNA stain) work well on paraffin sections? Does anyone have a protocol they would like to share? I am assuming that histological stains (like the Feulgen stain would work better?). I could also try both. Thank you in advance All the best Alida -- Dr. Alida M. Bailleul Associate Research Fellow/Associate Professor Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences www.ivpp-avianevolution.com<http://www.ivpp-avianevolution.com> & Research Associate of Paleontology, Museum of the Rockies, Montana State University Google Scholar <https://scholar.google.co.jp/citations?user=Yn4PuWMAAAAJ&hl=en> - ResearchGate <https://www.researchgate.net/profile/Alida_Bailleul> _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet