[Histonet] oysters larvae again
John A. Kiernan
jkiernan <@t> uwo.ca
Thu Mar 23 11:15:27 CST 2006
Anne Sophie's MEMPFA-T fixative (0,1 M Mops pH
7,4; 2 mM EGTA; 1 mM MgSO4; 4% paraformaldehyde;
0,1% Tween 20) does contain EGTA, which chelates
calcium ions, but 2mm seems intuitively to be very
weak. Are the shells of oyster larvae extremely
I've not come across this MEMPFA-T fixative
before. Could anyone provide a reference for it?
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London, Canada N6A 5C1
"Monfils, Paul" wrote:
> I don't have a background in ISH, so I can't offer an opinion on the best
> fixative for that purpose.
> Regarding your second question, while I'm not familiar with either fixative,
> I can see that the Davidson fixative, containing 10% acetic acid and no
> buffers, would decalcify (dissolve) larval oyster shells. But the MEMPFA-T
> appears to be made up in pH 7.4 buffer, in which case I don't see how it
> would decalcify. In any case, I am wondering why you are using a
> formaldehyde-based fixative for TEM? Ordinarily a glutaraldehyde-based
> fixative would be preferable for TEM.
> > ----------
> > From: histonet-bounces <@t> lists.utsouthwestern.edu on behalf of
> > Anne-Sophie MARTINEZ
> > Sent: Tuesday, March 21, 2006 5:13 AM
> > To: histonet <@t> lists.utsouthwestern.edu
> > Subject: [Histonet] oysters larvae again
> > Hello,
> > (1) I plan to fix oysters larvae/juveniles (4 month) for in toto ISH.
> > Which fixative is the best : Davidson (10% formaldehyde 37-40%, 30%
> > ethanol 95%, 60% seawater, 10% acetic acid) or MEMPFA-T (0,1 M Mops pH
> > 7,4; 2 mM EGTA; 1 mM MgSO4; 4% paraformaldehyde; 0,1% Tween 20)?
> > (2) Would it be possible to use the MEMPFA-T to fix and "decalcify" the
> > shelves of the juveniles for TEM (embedding in type lowyril, unicril,
> > LR-white resins) instead of classical fixative (4% PFA) and then EDTA?
> > Thank you very much again.
> > Anne-Sophie
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