Sick amoeba ?

[ddy5]

Does anyone know what's going on with this amoeba? There were several individuals of the same species in that particular sample, and all had the strange inclusions.

The amoeba is approximately 250µ long x 150µ wide. The largest circular inclusion is about 55µ in diameter and the 'dots' inside it are 2-3µ across.

Thanks, David
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Mystery-amoeba.jpg (135.21 KiB) Viewed 425 times

[NachoBen]

Nice picture!

Perhaps some colonies of endosymbiotic (or parasitic) bacteria? You'd better ask Ferry Siemensma (https://arcella.nl/).

Good luck! Please make sure you report here your results. Thank you!

[ddy5]

Great idea! I contacted Siemensma this morning and got a prompt reply suggesting a parasite of some kind.

Could it be some sort of fungus or mold where all the little dots are spores waiting to be released?

[NachoBen]

Although I don't know much about microscopic fungi, occasionally I have observed the release of zoospores



and in all cases the zoospores measured several µm. Since your "dots" do not appear to be much larger than 2 µm, they fit well into the size range of bacteria.

By the way, what amoeba is this, according to Ferry?

[ddy5]

An expert over on photomicrography.net says that this is "a Microsporidium-like parasite. Since the nucleus seems uneffected, the parasite most like is a Morellospora species." The dots inside the circular inclusions are tiny spores that can infect other amoeba when released.

[NachoBen]

Very very interesting. Mystery solved! Thank you very much!