MicrobeHunter.com Microscopy Forum

I don't know what that is but you have admirable tracking skill.

Wow nice video. What is it?

BramHuntingNematodes wrote: ↑

Tue Mar 17, 2020 1:53 pm

I don't know what that is but you have admirable tracking skill.

I second that It looks like an automated vision tracking.

I believe this is a pair of metopid ciliates (Metopus, etc.) in conjugation. Ciliate sex!

I believe this is a pair of metopid ciliates (Metopus, etc.) in conjugation. Ciliate sex!

Much more graceful than humans

Bruce Taylor wrote: ↑

Tue Mar 17, 2020 10:44 pm

I believe this is a pair of metopid ciliates (Metopus, etc.) in conjugation. Ciliate sex!

Is that really what this is? I'm trying to find other videos or articles on ciliate sex but I can't find much. I can't see any crease that would divide this into two different ciliates. Luckily this came from my ecosphere so I can at least try and find more. This was also filmed with no coverglass which is why it had so much freedom to move.



This ciliate sex tape isn't as theatrical, maybe cause a coverglass restricted movement.

micro wrote: ↑

Tue Mar 17, 2020 11:18 pm

Is that really what this is?

It's my best guess, at the moment, but I certainly could be wrong. This might also be a kind of ciliate "monster" called a homopolar doublet (which can be caused by conjugal failure). What it is not is a single organism in its "normal" vegetative condition.

The reason I suspect it is a metopid is that we seem to catch glimpses of an oblique anterior fold, at several points in the video. However, it is not particularly clear.
I agree that there is not much of a clear line between the conjugants (assuming that is what they are). However, conjugation entails a fusion of membranes, and the way this is accomplished varies a great deal from one genus to the next. Here's an SEM of a couple of metopids getting it on (a different species, but you get the idea):
...and one more (Metopos boletus):
Source: https://www.sciencedirect.com/science/a ... 3919300161

This morning, while reading a classic paper on ciliate conjugation, I learned something interesting. I think it explains what we are seeing, here!

As I mentioned above, I suspect the ciliates in this video are metopids (because of distinctive cell features, visible at several points in the video). Well, it seems that some species of Metopus engage in "total isogamontic conjugation." What this means is that conjugating partners of equal size form an unusually broad link (cytoplasmic bridge), across which genetic material is transferred. In most ciliates, genetic material is transferred both ways, and when this is accomplished, the two conjugants separate and swim away. In Metopus sigmoides, one of the two cells transfers much of its cytoplasm to the other (including all of its divided micronuclei). When the process is complete, one of the two cells is left as a shrunken remnant, devoid of germline DNA. It dies, soon afterwards.

I think we are seeing the early stage of this total conjugation, during which there is an unusually extensive cytoplasmic fusion of two cells of similar size. The process was recorded and fully illustrated by Lowell Noland in 1927: https://onlinelibrary.wiley.com/doi/pdf ... 1050440206
I learned about Noland's work on Metopus from Igor Raikov's "Nuclear Phenomena During Conjugation and Autogamy in Ciliates": https://www.sciencedirect.com/science/a ... via%3Dihub

I see Michel-Marie has recorded metopid conjugation, too! https://www.youtube.com/watch?v=mmUbGbEb6NM

The michel marie video must have been filmed with a cover glass since they aren't spinning and they look kind of flattened. If I ever see this process again maybe I will try to film it all the way to the end.

micro wrote: ↑

Thu Mar 19, 2020 6:41 pm

The michel marie video must have been filmed with a cover glass since they aren't spinning and they look kind of flattened. If I ever see this process again maybe I will try to film it all the way to the end.

Funny you should say that...I remember him telling me he didn't use coverslips! Not sure if this video is an exception, or not. In any case, this is likely a different species of metopid, and could well be a different genus.