Sarah Guest

🚨Our collaboration with @centriolelab.bsky.social & @gautamdey.bsky.social is out today in @cp-cell.bsky.social
We show that #Expansion #Microscopy is a broad-spectrum modality for Euks, enabling 3D phenotypic maps rooted to phylogeny.
#ProtistsOnSky #SciComm #SciSky

www.cell.com/cell/fulltex...

Our lab’s variegated peperomia makes green flecks on leaves, but only on the abaxial side. It’s the typical sandwich: L1 green-L2 yellow-L3 green, so guessing flecks are L1-derived cells dividing periclinally into L2. But how only on the abaxial side? Something to do with the super thick epidermis?

Just for fun, here's a game I like to call "Find the neuron" with examples of olfactory sensory neuron images from Šmít et al 2017 (doi.org/10.7554/eLif...) and Filoreta ramosa, a free-living syncytial amoeba from a salt marsh.

My PhD work is up on bioRxiv! Read all about the #actin and #microtubule #cytoskeleton of the Rhizarian #amoeba Filoreta ramosa here: www.biorxiv.org/content/10.1...

Autumn is just the best

This is glorious! And diatoms are as weird as ever!

Happy to have contributed to this great article: #Protist genomics: key to understanding eukaryotic evolution. Congrats Alexandra Schoenle et al. #ProtistsOnSky
authors.elsevier.com/sd/article/S...

Highlighted paper! Daisuke Yamagishi, et al. open a new front in the drive to understand photosymbiosis in protists.

Article➡️ doi.org/10.1111/jeu....

#protistsonsky

Synopsis: A hungry amoeba attempts to eat another amoeba roughly equal to its own size. After numerous failed attempts to engulf it, and briefly losing it in a mess of detritus, it encounters a flailing nematode. Fearing for its life, it abandons its prey, and finally captures a smaller meal.

An amoeba movie I made: "hungry" #protistsonsky #amoeba

Microbial Marvels, Microscopes, Math, and Mentorship by Ben Larson for Living Futures

I contributed an essay and some images to the new Living Futures series, an outgrowth of the fantastic Living Histories series organized by Sri Biswas and others.
medium.com/@thelhseries...

iyerbiswas.com/outreach/liv...

1/3

Poor dude can't catch dinner #protistsonsky #amoeba

Graphs showing 25 years of budgets for the National Institute of Health, NASA, and the NSF. In all cases, the proposed budget for next year is far, far below any year of the previous quarter century.

There are 2 previous historical cases of countries destroying their science and universities, crippling them for decades: Lysenkoism in the USSR and Nazi Germany. The Trump administration will be the 3rd.
It's not just budgets but research, institutions, expertise, and training the next generation.

Another bog friend #protistsonsky

The inside of our net was coated with these tiny jelly balls. I asked @blancobercial.bsky.social if they were some kind of ctenophore, but he said (enthusiastically) "No! These are #Rhizaria!" He is holding a single cell here. #marinelife #protistsonsky

Evidence for #recombination, and maybe #meiosis, in free-living #Rhizaria! I wish the results were clearer. As so often we raised more questions than we could answer :) If you are into #sex and the #meiosis-toolkit, this is an important read! #ProtistsOnSky link.springer.com/article/10.1...

New paper out in @pnas.org

We followed cells migrating along signalling gradients in 3D, and found they collectively behave as a living droplet - a self-propelling fluid that grows.

www.pnas.org/doi/10.1073/...

Myosin 2 drives actin contractility in fast-crawling species outside of the amorphean lineage https://www.biorxiv.org/content/10.1101/2025.05.16.654244v1

A quick craft project: hand-cut phase annuli from construction paper to fit an "adopted" microscope that was missing ph1 ph2 and ph3

I thought internal flagella was a characteristic of ALL spirochetes, not just Borrelia?

Also yes. Glad to know someone else is aware of their lovely microtubule arrays!

There were also several heliozoans resembling Raphidocystis pallida, with clustered spindle-shaped scales among their axopodia! I'll add another picture today if I get a chance.

Yes, I was very excited to find this individual and several others in the sample. It's always fun to find a non-Amoebozoan amoeba! The SAR are near and dear to my heart as well.

It's hard to see from the image, but at this stage there were some vacuoules and clear cytoplasm inside the new shell, just none of the cell's larger and pigmented organelles

Yes, from what I saw at the start, and from this observation (below), the new shell is secreted first from the opening and assembled from within arcella.nl/lesquereusia...

Yes, I agree! Especially long hours at the microscope too, when your cells are a bit slower than the charismatic Lacrymaria. Amoebae tend to need to be a bit sped-up in post!

I knew I had to stick around to watch the process!

Acanthocystis (maybe?) from the same bog sample. Sometimes amoebae don't need phase contrast, especially if they're full of zoochlorellae/plastids! #protistsonsky #bogblog

Thanks!!