Electron Micrograph of vesicles...

[IbelieveIAm]

Hello everyone,

I have two questions concering the micrograph attached.


What would the function of this cell be?
and where would the vesicles come from?


Thank you for your help!!

God bless.

[satrohraj]

Wikipedia has got lots of information on Vesicles.
Try it.

http://en.wikipedia.org/wiki/Vesicle_%28biology%29

[Darby]

That's a pretty weird vesicle, and it looks like it's got something in the middle of it that's another organelle entirely. I'll take your source's word for it that it's a vesicle, but it looks more like an inclusion (it looks a little bit like an apicomplexan caught at an odd angle by the section).

The very dark spots are material that's absorbed a lot of the stain - this would suggest lipids of some sort, reinforced by the blobby shapes.

My suspicion is that, if this is a question you're expected to answer rather than something you've found on your own, then you have a source with something very like this in it. But take it from someone who's done work in ultrastructure, that's an odd structure.

[blcr11]

I think it's a mast cell. The numerous granules should have been a giveaway, but I didn't realize that mast cells could have so many microvilli. The thing in the center is the nucleus, I'm pretty sure, surrounded by lots of protein/histamine-rich granules. The surface villi reminded me a lot of brush border cells, which can also have vesicles and granules, but they aren't usually so prominent--but, more importantly, brush border cells are polar and form laminar structures and this was clearly an isolated non-polar cell. I was guessing it was some kind of storage or secretory cell with all those granules, but which one I couldn't say. Then I stumbled on a picture of a mast cell that looked similar enough to this one that I would be willing to call it a mast cell.

The mast cell is part of the immune system. It makes things like histamine, cytokines, and proteases and stores them in all those dense-looking granules. Their surfaces are coated with IgE receptors and when stimulated by IgE-antigen complexes, they release the contents of the granules into the surroundings to promote additional immune responses like signaling the migration of eosinophils/neutrophils into the area and/or complement activation.

[Darby]

It seems like if it was a mast cell mature enough to have all of those vesicular bodies, it would be well past the single central nucleus stage - they have partially fragmented lobular nuclei, I'm pretty sure.

I'm also unsure as to what's around it - it doesn't seem completely cellular, nor a connective matrix, nor support medium (although maybe that if it's overstained, which would explain the blackness of the vesicles).

[IbelieveIAm]

Thank you so much for all your replies!

It is indeed a mast cell, I forgot to meantion that! Sorry! That fact meant nothing to me, so I guess that's why I forgot to mention it. Plus I was in a hurry. And I was so busy analysing vesicles that I didnt think to search 'mast cell'. oops.

The middle is a nucleus, surrounded by vesicles and a folded plasma membrane. I should have mentioned that too, but like I said I was stressed at the time and in a hurry.

Thanks again!