[Coral-List] coral fixation and decal
goldberg at fiu.edu
goldberg at fiu.edu
Thu Jan 15 12:42:19 EST 2004
I may as well throw my two cents in on this topic. While
it is true that there is nothing standard when it comes to
fixation and decalcification of corals, there is a
considerable literature on how to decalcify vertebrate
tissue. It would be a mistake not to consider all of that
work, depite the differences in mineralization between
the two systems. Take a look at Callis et al., Journal of
histotechnology 21: 49-58, 1998 for a review. If you are
not planning on anything more than standard histology,
you can do pretty much anything that has been
suggested. However, if you plan on looking at cell
structure or tissue relationships, the literature is pretty
clear that fixation and decalcification methods do
matter. Unbuffered formalin or strong mineral acids, for
example, will distort the cytoplasm and cause the loss
of proteoglycan typical of calcified material (see
Goldberg, Tissue and Cell 33: 376-387, 2001). For my
own general work with coral tissues I use a somewhat
hypertonic medium compared to seawater: 2.5-3%
glutaraldehyde + 0.15 M NaCl buffered with 0.1 M
cacodylate to pH 7.6-7.8. For decalcification of small
specimens I use 2% ascorbic acid (Dietrich & Fontaine,
Stain Technology 50: 351-354, 1975) or 5% lactic
acid/k-lactate buffered to pH 4 for larger chunks (see
Eggert & Germain, Histochemistry 59: 215-224, 1979).
I will be happy to provide more specifics once I know
what you are looking for.
best wishes,
wmg
Walter M. Goldberg
Professor of Biological Sciences &
Marine Invertebrate Search Committee Chair
Florida International University
Department of Biological Sciences
University Park
Miami, FL 33199
e-mail goldberg at fiu.edu
URL www.fiu.edu/~goldberg
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