[Cnidaria] Answer to "Tentacle histology"

[MARYMEGAN DALY]

Hi Daniel-

I'll second most of what Elsa wrote, and contribute the following:

The nematocysts are probably basitrichs (basitrichous isorhizas).  The staining makes it hard to actually see its structure, but  these are the only kinds of nematocysts reported from the tentacles of Nematostella.

The layer you have labeled "mes" is the mesogleal component of the ectodermal muscle layer.

At least some of the cells marked with a query look to me like partial sections through nematocytes or nematocysts--when the section glances off a capsule,or the capsule falls out of the section (because it is of such different density than the surrounding tissue) you can see a large space with nothing in it, or a space with a small, uniformly-stained bit of capsule in it.  

If you haven't already, you may want to look at 
Frank, P., and Bleakney, J. S. (1976). Histology and Sexual Reproduction of Anemone Nematostella vectensis stephenson 1935. J. Nat. Hist. 10, 441-449.  

Cheers
Meg

****************************
     Marymegan Daly
     Assistant Professor
     Dept. Evolution, Ecology and Organismal Biology
     Ohio State University
     1315 Kinnear RD, Columbus OH 43212
     (614) 247-8412

----- Original Message -----
From: Elsa Denker <elsa.denker at snv.jussieu.fr>
Date: Friday, December 14, 2007 6:36 am
Subject: [Cnidaria] Answer to "Tentacle histology"

> Hi Daniel,
> 
> We have studied the histology of Clytia hemisphaerica (hydrozoa) 
> tentacle and tentacle bulb by performing Epon semi-thin sections 
> followed by toluidine blue staining, so I will try answer some of 
> your 
> questions.
> - First, I confirm that the dark blue structures you observe are 
> nematocysts.
> - Concerning the type I am not an expert but you can have a look 
> to Gaby 
> Kass-Simon's review (Can.J.Zool.80:1772–1794(2002)) and they could 
> be 
> basitrichous isorhiza or homotrichous anisorhiza (or microbasic 
> mastigiphores ??). But again there is probably someone on the list 
> that 
> could give you a more accurate answer.
> - I agree that your "Spir" are probably spirocytes, I also think 
> that 
> "Gland" are gland cells. For the other cell types you observe it 
> is 
> quite difficult for me to answer. I am not sure that the cell with 
> a 
> white cytoplasm is a myoepithelial cell, beacause -if it belongs 
> to the 
> same cell-, there are intriguing blue and purple apical structures 
> that 
> could be reminiscent of sensory structures (??).
> - Concerning the origin of nematocytes in the anemone, I think 
> that 
> contrary to what is generally observed in hydrozoans, nematocytes 
> are 
> produced directly in the tentacles in anthozoans. (I can give you 
> one 
> reference : Jane Westfall, Cell tissue research (Zeitschrift für 
> Zellforschung) 75, 381--403 (1966)).
> 
> I hope these comments will be useful for you !
> Best wishes,
> Elsa
> 
> -- 
> Elsa Denker
> PhD student
> "Evolution and Development" team
> UMR 7138
> Université Pierre et Marie Curie (Paris VI)
> Bât. A, 4e étage, case 05
> 7, quai Saint-Bernard
> 75252 Paris Cedex 05 (FRANCE)
> Tel.: (33) 1 44 27 35 83
> 
> 
> 
> > ----- Original Message -----
> > *From:* Daniel Sher <')" >dsher at MIT.EDU>
> > *To:* cnidaria at uci.edu <')" >cnidaria at uci.edu>
> > *Sent:* Friday, December 14, 2007 2:48 AM
> > *Subject:* [Cnidaria] Tentacle histology
> >
> > Hi everyone,
> >
> > I am trying to understand a histological section (EPON, 2 
> micron, 
> > Methylene Blue staining) of a tentacle of the sea anemone 
> Nematostella 
> > vectensis (attached). I'd be glad for any input about this 
> section, 
> > especially regarding:
> >
> > a) Am I correct that the dark structures are nematocysts? Anyone 
> know 
> > what type?
> >
> > b) Are the lightly-stained (and not very common) large cells in 
> the 
> > ectoderm "simply" ectodermal epithelial cells?
> >
> > c) What are the cells marked by a question mark? They seem to 
> have 
> > basal nuclei, but the cells themselves extend towards the 
> surface. 
> > Could they be sensory neurons?
> >
> > d) Any other cells I should expect to see in such a sample? 
> > specifically, are there any cells (apart from ganglion cells) in 
> the 
> > ectoderm which do not extend to the surface?
> >
> > Also - does anyone know whether, in sea anemone, Nematocysts are 
> > produced from precursors within the tentacles, or do they 
> migrate from 
> > the body column like in Hydra?
> >
> >
> > Thanks!
> > Daniel Sher
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Daniel Sher
> > Postdoctoral Fellow, Chisholm lab
> > Department of Civil and Environmental Engineering
> > MIT
> >
> > Room 48-106, 15 Vassar St., Cambridge, MA 02139
> > Phone 617-253-1857 (office); 617-253-8686 (Lab)
> >
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> 
> 
> 
> 
> 
> 
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