Any ideas as to what is happening here?

chrismower · Post by **chrismower** » Tue Mar 05, 2013 12:02 pm

What looks like the worlds smallest Space Hopper seems to have something going on towards the end where it either is splitting or being attacked. Have a look at the video here on Youtube.

http://youtu.be/ajqbJj8nges

Any ideas?

Bruce Taylor · Post by **Bruce Taylor** » Tue Mar 05, 2013 1:57 pm

It's a ciliate, having serious trouble with osmoregulation. Protozoa have to expel water, periodically, to make up for the fluid they take in by osmosis (especially in fresh water). For some reason, this guy is unable to accomplish this task. It's a fairly common nuisance, in freshwater microscopy...some ciliate groups are more susceptible than others.

This guy is so puffed up, it's hard to tell what he might be ...

chrismower · Post by **chrismower** » Tue Mar 05, 2013 2:01 pm

There were literally dozens of these little critters of various sizes but they all looked very similar in shape. Do you think this was a natural activity or could it have been stressed by being under a coverslip. I often wonder if the surface tension around the edge of the coverslip has an effect on the pressure of the water.

Bruce Taylor · Post by **Bruce Taylor** » Tue Mar 05, 2013 2:32 pm

Yes, the weight of the coverslip and lamp heat (depending on how your scope is set up) can induce "blebbing."

If I had to guess, I'd say he was a free-swimming Peritrich, of some kind (that little nipple at the posterior looks like the scopula, where the stalk would normally be). In any case, he's clearly in some distress.

chrismower · Post by **chrismower** » Tue Mar 05, 2013 3:22 pm

I'm not sure if it comes across in the video but it looked to me as if it was completely covered in cilia. Would that fit with it being a Pentrich?
Hopefully it wasn't stressed for too long as I always try to return the specimens back to the pond after observing them. I know it sounds daft but I really don't like killing things just for my own amusement.

Bruce Taylor · Post by **Bruce Taylor** » Tue Mar 05, 2013 5:35 pm

If it was uniformly ciliated, you're right...that's not consistent with a Peritrich. I found it a little hard to tell, and for some reason couldn't increase the size of the video (I'm at a ski resort, using borrowed internet access...maybe that's why

). Vorticellids and Epistylids often have a posterior ciliary wreath, as well as the famliar peristomal cilia, but you would not see cilia elsewhere on the cell.

Bruce Taylor · Post by **Bruce Taylor** » Wed Mar 06, 2013 6:52 am

Watching the video at full size, I see that what I thought might be a Peritrich scopula is probaby the mouth of a very bloated Haptorid (the group that contains Phialina, Enchelys, Didinium, etc.).