Nematocysts

pwnell · Post by **pwnell** » Sat Jun 07, 2014 1:10 pm

20140607-DSLR_IMG_0011-Edit.jpg by pwnell, on Flickr
Aiptasia - unfired nematocyst,60x/1.2*1.6, DIC

20140607-DSLR_IMG_0153-Edit.jpg by pwnell, on Flickr
Aiptasia fired nematocyst,60x/1.2*1.6, DIC, HF B

20140607-DSLR_IMG_0181-Edit.jpg by pwnell, on Flickr
Aiptasia partially triggered nematocysts,60x/1.2*1.6, DIC

carlos.uruguay · Post by **carlos.uruguay** » Sat Jun 07, 2014 2:17 pm

Very very good!

rjlittlefield · Post by **rjlittlefield** » Sat Jun 07, 2014 2:45 pm

Excellent images!

And now I'm curious: how does one get a partially triggered nematocyst?

I had always thought that nematocysts were essentially spring-loaded with a trigger mechanism, but that doesn't explain partial triggering.

--Rik

pwnell · Post by **pwnell** » Sat Jun 07, 2014 4:31 pm

rjlittlefield wrote:And now I'm curious: how does one get a partially triggered nematocyst?

I had always thought that nematocysts were essentially spring-loaded with a trigger mechanism, but that doesn't explain partial triggering.

--Rik

No idea - but it looks like a state in between the untriggered and triggered versions... So hence my assumption...

Ichthyophthirius · Post by **Ichthyophthirius** » Sun Jun 08, 2014 2:17 am

Beautiful!

rjlittlefield wrote: And now I'm curious: how does one get a partially triggered nematocyst?
I had always thought that nematocysts were essentially spring-loaded with a trigger mechanism, but that doesn't explain partial triggering.

The discharge energy is stored in form of the twist of the filament as well as osmotic pressure (p1781ff, http://www.biochem.uci.edu/steele/Kass-Simon.pdf ). When some of the osmotic gradients are released during the preparation of the nematocysts, it could result in partial evagination. And there will also be "manufacturing faults" with some cysts

Bruce Taylor · Post by **Bruce Taylor** » Sun Jun 08, 2014 6:18 am

Great details of an interesting subject!

pwnell · Post by **pwnell** » Sun Jun 08, 2014 9:45 am

Thanks for the information.

I do believe these are two different kinds of nematocysts. The Aiptasia anemone has the smaller nematocysts (the second image of the triggered nematocyst) all in the periphery of its tentacles. However, in structures that resemble mesenterial filaments the larger nematocysts (images 1 & 3) are present. They are at least 2-3 times as large and looks slightly different.

This is just observational and nothing definitive.

discomorphella · Post by **discomorphella** » Sun Jun 08, 2014 11:11 pm

Really beautiful images of isolated nematocysts. How did you isolate them? I was going to macerate some Aiptasia, decided to fully microtome them instead. There are definitely several different appearing types of nematocysts in the cross sections. I'll have to try and find ones that look like your closeups. Great shots.
David

pwnell · Post by **pwnell** » Mon Jun 09, 2014 12:03 am

discomorphella wrote:Really beautiful images of isolated nematocysts. How did you isolate them? I was going to macerate some Aiptasia, decided to fully microtome them instead. There are definitely several different appearing types of nematocysts in the cross sections. I'll have to try and find ones that look like your closeups. Great shots.
David

I am afraid my response will disappoint you. I merely placed a polyp on a slide and searched for isolated nematocysts. I have no way of manipulating things that are 13µm long.