Heterolobosean amoeboflagellates?

[hans]

Previous, possibly-related observations:

• Green algae (?) with steady internal swirling motion (possibly cysts)
• An amoebozoan in order Leptomyxida? (no, probably class Heterolobosea)
• Euglenid? (possibly the flagellate form)
• Amoeba video processing (more examples of sustained, eruptive movement characteristic of Heteroloboseans)

I saw several more biflagellates gliding with one flagellum beating and the other trailing on the substrate, which is the form I was referring to when Bruce (apparently correctly) observed:

... (the "fairly rigid-looking" one did not look particularly "rigid", to me).

These ones are more obviously changing shape while gliding but otherwise look similar:


One difference between this gliding form and the eruptive form (video, video) are what appear to be uniformly-sized granules packed closely (~500 nm spacing) around the periphery of the gliding cells, also visibly in the attached photos of less active cells that perhaps are in the process of transitioning to or from cysts? I saw quite a bit about perinuclear granules in amoeba but so far have not found anything about what these ones at the periphery of the cell might be or if there is a name for them.

[hans]

After watching a few more I really think the swirling/tumbling motion is internal. There is no apparent disturbance of stuff surrounding the cell and there appears to be quite a bit of relative among contents at different depths within the shell, inconsistent with the entire cell rotating and the contents being stationary relative to the outer membrane:


This looks like exocytosis of something (resembling small fried-egg-looking cyanobacteria or algae I see in the sample) from a flagellate. One flagellum is occasionally visible just above in the frame, I think, not moving much:


More cysts with perinuclear granules visible:

DSC_9354.jpg (99.45 KiB) Viewed 1821 times

[Bruce Taylor]

Excellent observations, Hans!