[Histonet] alizarin red fading

[Barry R Rittman]

I cannot see why the addition of a few crystals of thymol would make the glycerin acidic enough to cause removal of calcium and thus leaching of the alizarin.  
If you are using 100% glycerin, there should be no need for the addition of thymol.
I am not sure exactly how you have processed these specimens. If you are using the classical method with potassium hydroxide (as the leaching agent to remove excess stain from soft tissues), is it possible that there were traces of potassium hydroxide left in the specimen? 
I have some specimens that were stained in 1961 and some in 1970 that show no signs of fading.
Barry

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Julien
Sent: Monday, September 13, 2004 3:59 PM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] alizarin red fading

Hello all,

We do differencial staining of bone and cartillage on small fish (~1cm). To do so, we use the Clear and Stain technique which results in red bone coloration and blue cartillage coloration. After a month or so, We noticed that the red stain tends to fade off. We tried to re-stain the fish, but the alizarin red wouldn't stain the bones anymore. 

Why is this so? Is it that bone decalcifies in the glycerin? We put a few cristals of thymol in the glycerin to avoid mold development. Could this be a decalcifying agent? Does anybody know of a way to re-stain?

For the time being, we score bony elements within 3 days of staining to avoid fading problems, but this stops us from doing batch staining. Batch staining would be much faster. We would then keep stained fish in glycerin until scoring.

Thanks for any suggestion.

Julien Lambrey de Souza
Biologie Évolutive,
Université du Québec à Rimouski,

 
Julien Lambrey de Souza
Biologie Évolutive,
Université du Québec à Rimouski,

(418) 723-1986 #1438
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