Archamoebae probably Mastigamoeba sp. (edited)

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carlos.uruguay
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Archamoebae probably Mastigamoeba sp. (edited)

Post by carlos.uruguay »

Living in very putrid seawater.
They have a long flegellum (in these organisms called cilium) that in the video then absorb.
They measure about 20um in length.
I thank Eckhard Völcker:
http://www.penard.de/Explorer/Amoebozoa/Archamoebae/
and Alastair Simpson:
https://www.dal.ca/faculty/science/biol ... mpson.html
the identification of this organism
Phase contrast.
40X and 100X immersion objective
Panasonic GH4 camera
Video link:
https://www.youtube.com/watch?v=uui7LbqoQxI
Video frames preview:
Image
Image
Image
Regards
carlos
Last edited by carlos.uruguay on Mon Jan 16, 2017 4:48 pm, edited 2 times in total.

zzffnn
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Post by zzffnn »

Very nice phase contrast!!
Selling my Canon FD 200mm F/2.8 lens

carlos.uruguay
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Post by carlos.uruguay »

Thanks!

Jacek
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Post by Jacek »

Super video

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Post by carlos.uruguay »

Thanks Jacek!
According to queries that I have made they are presumably a pelobiont

Ecki
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Post by Ecki »

Carlos,

thanks for this very nice video. These are Archamoebae cells, probably a Mastigamoeba sp..

These amoebae have a couple of interesting traits. They live in anaerobic or micro aerobic habitats. Without real mitochondria and a with a cilium that is attached to the nucleus. Amoeba of this group were once thought to be ancestral amoebae because of the lack of real mitochondria and the nucleus-attached cilium. But we know now that these once were aerobic amoebae that are specialized to live in micro aerobic habitats, thus having lost oxygen-requiring mitochondria.

For some members of this group sexual processes have been observed. They produce gametes. A cell will either produce micro gametes with a cilium or macro gametes without a cilium. When both gametes fuse, the cilium of the micro gamete will become the forward pointing cilium of the new amoeba. There are stages without the cilium, the video shows the retreat of the cilium in an exemplary way. In the video this is probably a reaction to the stress under the coverslip.

Some more images of Mastigamoeba are here: http://penard.de/Explorer/Amoebozoa/Archamoebae/

Best regards,
Ecki

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Post by carlos.uruguay »

Many thanks Ecki!!!!!!!!!!
I'm going to edit the text of the video
Why is it called long cilium and not flagellum? Is it structurally different from a flagellum?

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Post by Ecki »

Some terms in biology are kind of fuzzy. Flagellates, algae etc. have a flagellum, ciliates have cilia. Bacteria also have a flagellum. Doesn't make too much sense ;)

So the modern definition is flagellum for prokaryotes and cilium for eukaryotes. The blueprint for a cilium is universal - the human sperm, the algae and your amoebae share the exact same structure. The is true too for the bacteria, its flagellum blueprint is also universal, it is shared among all bacteria which have a flagellum. This shows how old these 2 blueprints are. The blueprint for the cilium must have been present in the DNA of the ancestor of nearly all eukaryotic lineages in the tree of life.

In distinction to most cilia of ciliates, I call this a long cilium because of its remarkable length - just compare the length of this organelle to the length of the cell.

Amoebae of this group are ubiquitous in most anaerobic or micro aerobic habitats. The are found in freshwater, brackish and sea water. They are often accompanied by Pelomyxa amoebae, pretty large and presumably lazy amoebae sometimes with hundreds of nuclei. Their body is often covered with cilia, sometimes 20-50 cilia, unevenly distributed over the cell, often in pairs of 2. They are "nephews" of the Mastigamoeba, having inherited the cilium. They don't use it for locomotion and nobody knows what is its role? It may just be an evolutionary leftover that will vanish over time. It may play a role in nutrient circulation, creating currents etc etc. We just don't know.

Carlos, I like the first part of your movie a lot. It shows nicely the locomotion and the movement of the cilium. The later parts show the amoebae dying :(

These amoebae are difficult to cultivate. Oxygen is poison!

Best regards,
Ecki

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Post by Pau »

Ecki wrote:Some terms in biology are kind of fuzzy. Flagellates, algae etc. have a flagellum, ciliates have cilia. Bacteria also have a flagellum. Doesn't make too much sense ;)

So the modern definition is flagellum for prokaryotes and cilium for eukaryotes.
As Biology teacher for many years I've never seen this distinction.
Prokaryotes have rotating thin flagella with a very different structure than eukaryotes.
In the last domain cilia and flagella have the very same structure and the term refers to its length: Many short ones are cilia while few or one long ones are flagella (cilium in Latin means eyelash and flagellum means whip). Because the very same structure some common names has been proposed like kinetosoma or undulipodia with no general success.

Could you link a reference for the bold marked sentence?
Pau

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Post by carlos.uruguay »

Wow!!! Thank you for your time and for such excellent information Ecki !! It's an honor to read you!

Ecki
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Post by Ecki »

Here you go, Pau.
Adl et al. (2005) noted that the preferred term for a eukaryotic flagellum is cilium, and we have now used cilium throughout this revision. For additional terms the standard guide remains Andersen et al. (1991), with the term flagellum substituted with cilium.
Adl, S.M., Simpson, A.G., Lane, C.E., Lukes, J., Bass, D., Bowser, S.S., Brown, M.W., Burki, F., Dunthorn, M., Hampl, V., Heiss, A., Hoppenrath, M., Lara, E., Le Gall, L., Lynn, D.H., McManus, H., Mitchell, E.A., Mozley-Stanridge, S.E., Parfrey, L.W., Pawlowski, J., Rueckert, S., Shadwick, L., Schoch, C.L., Smirnov, A., Spiegel, F.W.: The revised classification of eukaryotes. J. Eukaryot. Microbiol., 59: 429–493 (2012).

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3483872/#

Best regards
Ecki

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Post by Bruce Taylor »

A wonderful video, Carlos! The attachment of the cilium to the nucleus is very clear. :)

Since eukaryote cilia and flagella are structurally identical and share common descent, it makes a lot of sense to use one word for both. Lynn Margulis and her collaborators made a valiant attempt to get everyone to use the word "undulipodium" for this organelle, but it's a hideous word, and never caught on. :D
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Post by fpelectronica »

Nice video. Very interesting

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Post by Pau »

Ecki, thank you very much for the interesting article.
I feel to need to search much deeply before changing nomenclature, as I read it is just a proposal of few (although relevant) authors, not still a consensus on cell nomenclature

For example, at Alberts et al.(2002) Molecular Biology of the Cell. 4th edition: While highlighting the identity of structure maintains the dual nomenclature
Quote:
Eucaryotic flagella are longer versions of cilia


Best wishes
Last edited by Pau on Tue Jan 17, 2017 12:42 am, edited 1 time in total.
Pau

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Post by carlos.uruguay »

Thank you so much Bruce and Francisco!

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