Histological problem

Lester Pasarell lpasarel at utmb.edu
Thu Feb 17 13:29:07 EST 2000

I have used paraffin embedded cross sections sections of fungi  as an
aid to identify some of the coelomycetes and or ascomycetes with
fruiting bodies. 
One example is http://fungusweb.utmb.edu/mycology/fungi/pleple.jpg
I usually cut the sample of agar with the pycnidium or fruiting body
load it into a
plastic cassette (the ones used for human biopsy samples that has tissue
paper or foam that does not allow the sample to float away), then I put
the cassette in formaldehyde for 24 hours. The histology laboratory will
usually do the embedding, sectioning and staining for me, but I usually
have to tell them to make deep cuts in the parafilm if the fungus is
deep within the sample, or else I will only see hyphae and not the
inside of the pycnidium.
I usually order a couple of unparafin mounted slides( to look under
phase microscopy) and slides stained with PAS or H& E, with both stains
you will be able to tell apart, hyphae , conidia, spores and
conidiogenous cells.
You can do the same with plant material, just be sure that the sample
you cut is small and that it surrounds the offending fungus

hope this helps



Melinda wrote:
> Is anyone familiar with paraffin techniques?  I am trying to show a
> phytopathogenic fungus in paraffin embedded material.  However, I feel as
> though I am doing something wrong.  I have embedded material that is known
> to be infected.  After sectioning, no evidence of the fungus is present.  I
> have tried various differential staining tecniques and have yet to be
> sucessful.  I am currently testing fixes to see if that is the problem.
> Does anyone out there have any suggestions?
> ---

Lester Pasarell		http://fungusweb.utmb.edu		
lpasarel at utmb.edu	Medical Mycology Research Laboratory

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