[Histonet] Using acetic acid alone as a fixative

[Bryan Hewlett]

Hi Gayle,

You are generally correct.
Essentially, the only proteins denatured (fixed) by acetic acid are the 
nucleoproteins.

However, 5% aqueous acetic acid has been used as a fixative for chromosomes 
in fresh material (commonly plant).
We used this in school to see mitosis in onion root tip, how's that for a 
six decade old memory?
I have also used this more recently (only four decades back) to fix cell 
cultures prior to staining for karyotype analysis.
Today most labs use acetic/methanol for this purpose.

The methods that I am familiar with, use either aceto-carmine or 
aceto-orcein as a combination fixative/stain for chromatin.
I am sure that John K. can also come up with a version for Nissl substance.


All the best for the season.

Cheers,

Bryan








----- Original Message ----- 
From: "gayle callis" <gayle.callis <@t> bresnan.net>
To: "Histonet" <histonet <@t> lists.utsouthwestern.edu>
Sent: Saturday, December 12, 2009 3:54 PM
Subject: [Histonet] Using acetic acid alone as a fixative


> Dear Histonetters,
>
>
>
> I have a person using acetic acid as a fixative for frozen sections
> containing bioluminescent proteins (GFP and tdTomato, a red fluorescent
> protein).
>
>
>
> I have always been taught to use acetic acid in combination with other
> chemical agents (e.g. as in Bouins  or Carnoys) but not alone due to the
> swelling of cells and tissues and probably other acid protein hydrolysis
> going on too.
>
>
>
> Has anyone ever run across using acetic acid (concentration is not high, 
> but
> not known by me)?  She does encounter problems with GFP staining, but the
> tdTomato still glows although her results are inconsistent.
>
>
>
> I have no clue where this fixation method originated from but I suspect it
> may be from a fixative where something was lost in making it
> up/forgotten/left out - ending up with acetic acid alone.  A quick look in
> Sheehan and Hrapchak's  Theory and Practice of HIstotechnology, indicated
> acetic acid was rarely used alone for fixation.  I am off to John 
> Kiernan's
> book after sending this message.
>
>
>
> I understand the sensitivity of GFP and some other GFP chimeras , also RFP
> (closely related structurally to GFP) to alcohols and other organic
> solvents, heat, and pH where fluorescence is lost and/or diminished
> significantly.
>
>
>
> Enlighten me please
>
>
>
> Gayle M. Callis
>
> HTL/HT/MT(ASCP)
>
>
>
>
>
>
>
>
>
>
>
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