[Cnidaria] Answer to "Tentacle histology"

Fri Dec 14 12:15:04 PST 2007

Hi Sonya, Elsa, Meg, Esti - and other cnidarianologists out there...

Thanks for all the advice. The question of anthozoan i-cells seems to be a 
bit unclear - doea anyone know whether they have i-cells or similar 
multipotent cells, and where these cells are situated? Specifically, we are 
interested in nematocyst and nerve cell precursors.

Thanks
Daniel

----- Original Message ----- 
From: "Sonya Pyataeva" <sonya.bio at mail.ru>
To: "Cnidaria Newsgroup" <cnidaria at uci.edu>
Sent: Friday, December 14, 2007 12:38 PM
Subject: Re[2]: [Cnidaria] Answer to "Tentacle histology"

> Dear Daniel,
> I agree with Elsa and Meg about nematocysts and gland cells.
> As for "Mes", that you labeled - I'm sure absolutely, it's a muscle layer 
> of basal ectoderm (it is oriented longitudinally in the ectoderm). And 
> mesoglea - is a thick dark blue line between the muscle layer and 
> endoderm).
> As for the ectodermal cells which do not extend to the surface, I know 
> that hydrozoans have interstitial cells (i-cells) - multipotent cells, 
> precursors of nematocytes, gametes, nerve cells, some gland cells. In 
> hydroids some of them begin to differentiate in the limits of endoderm and 
> then migrate to the ectoderm in the process of metamorphosis. But some of 
> them do not change, penetrate the mesoglea and are situated in the basal 
> portion of ectoderm in the intercellular space (sometimes in groups). 
> Don't i-cells exist in all cnidarians? I'm not sure, but I believe so 
> (maybe somebody could correct me...). These cells should be round, small, 
> dark blue and contain a large nucleus.
>
> cheers,
> Sonya
>
> -----Original Message-----
> From: MARYMEGAN DALY <daly.66 at osu.edu>
> To: Cnidaria Newsgroup <cnidaria at uci.edu>
> Date: Fri, 14 Dec 2007 07:56:25 -0500
> Subject: Re: [Cnidaria] Answer to "Tentacle histology"
>
> 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 fЭr
>> 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
>> UniversitИ Pierre et Marie Curie (Paris VI)
>> BБt. A, 4e Иtage, 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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> __________________________________________________________
> Sofia V. Pyataeva
>
> Dept. Invertebrate Zoology
> Faculty of Biology
> M.V.Lomonosov Moscow State University
>
> Leninskie Gori
> Moscow 119 991
> RUSSIA
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