[Histonet] DAB enhaced with Nickel Sulfate Ammonium

[Alonso Martínez Canabal]

   Good Afternoon.
        It is great to be in this list again. My first e-mail is to ask
your advise about a little problem that we have in the lab.
       We are doing immunohistochemistry in brain tissue using DAB enhanced
with nickel ammonium sulfate. The result is great, with a very clean signal
in 50um thickness brain sections. Our problem is that later we do some
counterstaining with methyl green. It is purified with chorophorm and in pH
4.2 in Acetate buffer. We clearly see the green nuclei and the
immunoreactive cells, but apparently, after the counterstaining, the
dark-purple-blackish precipitate is gone and we can only see regular brown
DAB.
     What do you think?
  I wonder if it is the pH of the Methyl green, but I am kind of lost here.
 Any advise?
     Thank you very much
           Dr. Alonso

-- 
Dr. Alonso Martínez Canabal PhD
Profesor Asociado "C"
Departamento de Biología Celular, Facultad de Ciencias, UNAM
Investigador Nacional "I"
56224833