[Histonet] calcaflour white

[John Kiernan]

The fluorochrome you mean is probably
calcofluor white M2R (CI 40622, CI Fluorescent brightener 28).

The name "calcofluor white" with various suffixes is
used for many of the fluorescent whitening agents that
are used to optically counteract the tendency of white
fabrics to become yellow with age. These compounds are
included in detergents used for washing clothes, for
example. They are not all chemically related and will
not all work the same way if used as fluorescent stains.

Check that the Colour Index number and name are those 
of calcofluor white M2R. 

This fluorochrome has many uses (see RW Horobin's
Chapter 22, "Polyene dyes and fluorochromes" in the
10th edn of Conn's Biological Stains, 2002). 

A fairly recent paper on the use of calcofluor white M2R 
for staining fungi is by R ruchel & M Schaffrinski (1999)
J. Clin. Microbiol. 37:2694-2696. They comment that this 
fluorochrome can crystallize at high pH and recommend 
another one called "blankophor-P", whose identity I cannot 
determine. It's generally unwise to use any staining
reagent that you don't know and understand, and foolish
to use one that nobody knows anything about.

For a simple staining technique using calcofluor white M2R
see J Aslanzadeh & PS Stelmach (1996) Infection 24:248-250.
(Their method is for Pneumocystis carinii but ought to be 
OK also for fungal hyphae.)  

All methods using calcofluor white M2R are much the same
and extremely simple: 
Immerse hydrated sections in a dilute aqueous solution
(about 0.1 mg/ml) for a couple of minutes, rinse in a few
changes of pure water, thoroughly air-dry, rinse in xylene, 
and coverslip with a non-fluorescent resinous mounting 
medium.
Excite with near-UV. The fluorescence is blue.

John Kiernan
London,  Canada.
__________________________________________________
Histology SLU <sluhisto <@t> yahoo.com> wrote on 2th October:
> 
> Anyone out there have a protocol or any information on doing calcaflour
> white for fungus on paraffin embedded human tissue???  Any help would be
> appreciated.  Thank you.
> 
> Susan