After a bit of digging - it looks like it's done to sharpen features as one of the standard steps in producing these images. Where there are rotational symmetries in the things they're looking at, they focus on the smallest unit, and then rotate accordingly. If you had a trilateral symmetry, or hexagonal structure, they'd rotate 3 or 6 times around the center.
You're not getting a real image of the thing, but apparently it's got data from those other segments mixed in with the rotations, so you're getting a kind of idealized structure, to make the details being studied pop out, but if you have some sort of significant deviation, damage, or non symmetric feature it'll show up as well.
So kind of like taking a picture of a human, and then taking each half, flipping along the midline, and blending to get an idealized Symmetrical Human?
I think that might just be the original and it simply is symmetrical to that degree. I found a few more examples of "cryo-em center slices" and I've yet to find one that doesn't have really strong symmetry down to the small dot patterns.
I remember someone talking about "last universal common ancestor" at some point, the single "origin of the cells" or something. Is that the same as the "archaeal ancestor" they're referring to here? And is the "archaeal ancestor" the same as the "Primitive archael cell" mentioned in the last image in the article? (https://www.tus.ac.jp/en/mediarelations/20251219_9539_03.png)
I believe "archaeal cell" is referring to an Archaea, one of the three branches of life. All three branches derive from a more distant ancestor, LUCA. LUCA was undoubtedly preceded by other ancestors, but there is (by definition) nothing else branching from them that has survived.
From what I know - There are two sister groups, the Archae and Bacteria. Their ancestor would be LUCA. The first Archae would be the archaeal ancestor. There should be a first bacteria to match that.
My brief, illustrated history of Microbial Mats (p.10) to Multicellular Eukaryotes (p.13) may be of interest:
https://impacts.to/downloads/lowres/impacts.pdf
Incidentally, anyone know what is going on with this image - “Cryo-EM map of a center slice of the ushikuvirus particle”: https://journals.asm.org/cms/10.1128/jvi.01206-25/asset/1357...
It’s one quarter of an image flipped horizontally and then vertically, you can see the patterns.
It’s a bit odd to do that? Shouldn’t it just be the original EM image?
https://www.sciencedirect.com/science/article/pii/S104784772... - there are similar results in this paper, too.
After a bit of digging - it looks like it's done to sharpen features as one of the standard steps in producing these images. Where there are rotational symmetries in the things they're looking at, they focus on the smallest unit, and then rotate accordingly. If you had a trilateral symmetry, or hexagonal structure, they'd rotate 3 or 6 times around the center.
You're not getting a real image of the thing, but apparently it's got data from those other segments mixed in with the rotations, so you're getting a kind of idealized structure, to make the details being studied pop out, but if you have some sort of significant deviation, damage, or non symmetric feature it'll show up as well.
It's called "imposed symmetry" https://discuss.cryosparc.com/t/what-is-actually-occuring-wh...
Neat stuff, cool thing to catch!
So kind of like taking a picture of a human, and then taking each half, flipping along the midline, and blending to get an idealized Symmetrical Human?
I think that might just be the original and it simply is symmetrical to that degree. I found a few more examples of "cryo-em center slices" and I've yet to find one that doesn't have really strong symmetry down to the small dot patterns.
A different paper, this figure shows a number of cryo-em images, including a simulation, and they all show the same degree of pattern symmetry https://www.researchgate.net/figure/Central-sections-through...
First figure in this third paper also shows symmetry of small patterns https://journals.asm.org/doi/10.1128/jvi.00990-22
Thanks, those examples make it pretty clear.
I still think it’s super weird that it looks exactly like an EM image, but is generated. Anyway, good to know!
According to this article the image is computed and not really directly captured https://www.chemistryworld.com/news/explainer-what-is-cryo-e...
Rampant fraud in science papers has reached the point where hobbyists can point out obviously fake charts and graphics even in prestigious journals.
Publish or perish needs to end.
I remember someone talking about "last universal common ancestor" at some point, the single "origin of the cells" or something. Is that the same as the "archaeal ancestor" they're referring to here? And is the "archaeal ancestor" the same as the "Primitive archael cell" mentioned in the last image in the article? (https://www.tus.ac.jp/en/mediarelations/20251219_9539_03.png)
I believe "archaeal cell" is referring to an Archaea, one of the three branches of life. All three branches derive from a more distant ancestor, LUCA. LUCA was undoubtedly preceded by other ancestors, but there is (by definition) nothing else branching from them that has survived.
I anticipate the definition will become increasingly subjective as we find biology-messiness inconsistent with our concepts of ancestry.
For example, suppose horizontal gene transfer occurs from organism X to organism Y. Does that mean Y is now a branch of X?
* Does it depend on how much was transferred?
* Does it matter only if the specific sequence was passed down? If so, how much mutation is too much mutation?
* What if the same end-result occurred through a retrovirus instead of a plasmid. Is the virus an ancestor too?
* What if the swap was simultaneous and bidirectional?
* What about transitive links to organisms W, V, U that did the same?
* Are mitochondria "us" yet? If so, are we the ancestors if they redevelop enough machinery to "escape"?
etc.
From what I know - There are two sister groups, the Archae and Bacteria. Their ancestor would be LUCA. The first Archae would be the archaeal ancestor. There should be a first bacteria to match that.
I believe that Eukaryotes then from Archae.
Interesting, hope that these discoveries can be used to fight those amoeba's which cause infections as well!