A question for any Amoeba experts out there

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chrismower
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A question for any Amoeba experts out there

Post by chrismower »

I have been scanning the water from my pond and I am seeing a lot of what I think are similar to Quadrulella Symmetrica in that they have a test which is made up of fragments of stone/quartz etc. and are of a roughly vase-shape. What puzzles me is that they all appear to be empty as there re no signs of pseudopodia and looking at them under phase contrast there doesn't seem to be anything inside the case.
Now what I'm wondering, since I know so little about the amoeba is could these be -
a. Abandoned tests
b. Dead amoeba
c. Something completely different altogether.

I have not been able to get any pictures of them yet but I will try to get some if necessary. It could be that they are nothing to do with amoeba and are the discarded cases of some other organism. My knowledge is scant at the moment, hence this post.

Anyone have any ideas?

Bruce Taylor
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Post by Bruce Taylor »

I'm no expert, but...I don't think Quadrulella use "found" materials (stone, quartz, etc.) in their siliceous tests. What you're describing sounds like Difflugia oblonga (though, of course, it's impossible to tell without seeing it).

If you haven't seen it already, you should have a look at Ferry Siemensma's amazing (and always improving!) site: http://www.arcella.nl/

Empty tests are left by amoeboids that have died.

Charles Krebs
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Post by Charles Krebs »

No expert here either, but you do come upon many empty tests.

I'll second the recommendation to visit Ferry Siemensma's site.

And it is also a real treat (and helpful for ID direction) to look at the plates drawn by Joseph Leidy over 130 years ago. Amazing work (click on a plate to enlarge it):
http://user.xmission.com/~psneeley/Personal/FwrPLA.htm

chrismower
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Post by chrismower »

Sorry, what I meant was that the things that I am seeing are just Quadrulella Symmetrica shaped. I have the excellent "Protozoological Monographs" by Martin Kreutz and Wilhelm Foissner and Quadrulella Symmetrica was the closest thing in there to what I was seeing in the 'scope.

I wonder why I have so many dead amoeba and no live ones. The water is healthy as there are no end of rotifers and other protists, all whizzing about like crazy.

chrismower
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Post by chrismower »

Thanks Charles for the link to http://user.xmission.com/~psneeley/Personal/FwrPLA.htm

We have a new possibility in Difflugia acuminata or Difflugia bacillifera.

So do the amoeba outgrow them or actually just die and leave the shell empty then. I counted about 16 empty tests and not a single one with any sign of something inside. I am perplexed.

chrismower
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Post by chrismower »

I have just stumbled upon this site which seems to be a very comprehensive guide to amoeba.
http://www.arcella.nl

Bruce Taylor
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Post by Bruce Taylor »

chrismower wrote:I have just stumbled upon this site which seems to be a very comprehensive guide to amoeba.
http://www.arcella.nl
That is Ferry's site. :)

As for the dead amoeboids...conditions that suit one organism may be all wrong for another. These tests might have fallen down from higher in the water column after their original owners had died. Or (as has happened in my own microbe aquarium) changing conditions might have caused your testate amoeboids to lapse into dormancy. In any case, the presence of abundant life does not mean that all types of creatures will flourish in that water. :)

chrismower
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Post by chrismower »

How did I miss the link to Ferry's site in your original post Bruce :oops: It's quite an amazing site for amoeba information.

Being a bit of a noob here it is sometimes difficult to tell what it is that you are seeing under the scope. I wanted to be sure that what I was seeing was in fact the test of an amoeba and not a seed pod or similar. I'm going to have to keep looking till I find a live one.

Thanks everybody.

Ecki
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Post by Ecki »

The shells exist much longer than the amoeba inside. It is normal that you find many more empty shells than shells with living amoebae.

Ferry
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Post by Ferry »

Without any picture it is nearly impossible to tell what you have actually seen. Even with good photomicrographs it can be puzzling. Vase like shells are not restricted to amoebae.

Cheers,
Ferry

chrismower
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Post by chrismower »

Ferry, that is what I was thinking when I asked the question. I couldn't take a picture at the time as I was using my Wild M40 and I had lent my camera adapter to a friend so I couldn't take a picture, but they did look like the classic testate amoeba. They were sort of amphora shaped with what looked like small pieces of debris stuck over the surface.
Here is a drawing that I made of one of the items.

Image

Ferry
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Post by Ferry »

Ok, I think your problem is: you have found a testate amoeba, but it has so may quadrangular plates in its shell, that you wonder what this might be. That's the reason you was thinking of Quadrullela. Correct?
But from your drawing I can only say it is a Difflugia. These amoebae gather their material while moving and feeding. Some strip their building material from empty shells, it's a nice kind of recycling ;-) But this is more common for Nebeloid-species, and not for Difflugias. So a micrograph is still most wanted! :lol:
Cheers, Ferry

chrismower
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Post by chrismower »

Actually I was just picking Quadrullela as that was the nearest shape that I had a picture of. I was seeing so may of these what appeared to be empty shells that I was not sure if they were actually amoeba or something else. I couldn't understand why they were all empty, but it would appear that it is not uncommon to have lots of empty shells because the occupant has died.

As I say I am a total newbie to this and find amoeba quite fascinating. That something with nothing in the way of a CNS should be capable of hunting down a Paramecium and encircle and devour it is quite astonishing.

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