Bruce & Mike,

I have tried adding 5% trichloroacetic acid (TCA) to Davidson's fixative to 
overcome the problem of penetration through the skin and scales of fish.  And yes, 
it works in this application, except that the fish sections tend to flake off the 
slides during staining.  Presumably, it's because the TCA is chewing up the 
proteins, a thing it's known to do in molecular biology applications.  However, if 
I presoak the fish in 5% TCA for a 4-6 hours, and then transfer my specimen to 
fixative, I get a specimen that is better infiltrated than either Bouin's-fixed or 
Davidson's-fixed fish during paraffin processing, and doesn't flake off during 
staining.  TCA is a known denaturing fixative, but apparently also simultaneously 
"unfixes" the specimen through protein cleavage.

If you try any of these TCA tricks, let us know the results.

Curious in Oregon

Karen Larison
   


Date:          Mon, 28 Jun 1999 18:55:54 +1000
From:          "Histomail\\" <histomail@netspace.net.au>
Subject:       Re: ANTS....Help!!
To:            "Bruce Abaloz" <b.abaloz@zoology.unimelb.edu.au>

Dear Bruce,
try collecting ants into 10% Formal Saline with 5% Trichloracetic acid and
allowing to fix for for 24-48 hrs , then try processing and sectioning.
Works well with whole nails, so why not ants?
Regards Mike Rentsch . Traralgon. Vic.
-----Original Message-----
From: Bruce Abaloz <b.abaloz@zoology.unimelb.edu.au>
To: histoNet@Pathology.swmed.edu <histoNet@Pathology.swmed.edu>
Date: Monday, 28 June 1999 9:27
Subject: ANTS....Help!!


>Dear All.....I have a student who would like x-sections & serial sections
of a species of ant which I have tried to soften the chitinous
exterior/exoskeleton with Bouin's & Perenyi's both under vaccuum for o'nite
periods to no avail...the little suckers are as rock hard as prior to
treatment! Can someone PLEASE offer advice/a solution that will do the
"trick"!? I thankyou in advance for any advice & await your reply/ies.
Cheers, Bruce in Oz.
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>BRUCE ABALOZ
>HISTOLOGIST
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>AUSTRALIA.
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