Deepa Rajan, PhD

Deepa Rajan, PhD

@deeparajan.bsky.social

MD/PhD candidate at UCSF researching the intelligence of single cells research summary: https://www.youtube.com/watch?v=Noq8wtqZKWY

256 followers71 following55 posts

Deepa Rajan, PhD
@deeparajan.bsky.social

I'm excited to be featured on one of my favorite podcasts!! I binged @nightsciencepod.bsky.social during my PhD. Listen to this episode to hear about how the crop rotation system can be applied to the scientific creative process. And learn about our beloved Stentor in Every School program!

The Night Science Podcast@nightsciencepod.bsky.social

🔥New Night Science Podcast episode! We talked with PhD students & postdocs about finding ideas in art museums, making sketches, transferring concepts, going to unrelated seminars, swimming, hiking, talking in pubs and letting ideas lie fallow like in a crop rotation system.

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Deepa Rajan, PhD
@deeparajan.bsky.social

There is still much left to learn – for both Stentors and the humans who study them! Which other molecules drive Stentor habituation? What else can they learn? By researching how a single cell learns, we can begin to shed light on the origins of intelligence. 13/n

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Deepa Rajan, PhD
@deeparajan.bsky.social

These findings are consistent with a receptor-inactivation mechanism for Stentor habituation: mechanoreceptor senses stimulus ➡️ channel opening changes membrane potential ➡️ CaMKII activation ➡️ protein phosphatase activation ➡️ dephosphorylation of mechanoreceptors. 10/n

Deepa Rajan, PhD
@deeparajan.bsky.social

But is this habituation memory localized? Can it persist in progeny? To test this, we trained cells with mechanical taps as they were dividing. The video below is sped up over 7 hours of training/dividing. 11/n

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Deepa Rajan, PhD
@deeparajan.bsky.social

Calcium/calmodulin-dependent kinase II (CaMKII), one of the RNA-seq candidates, is essential for learning in animals. We found that KN-93, a drug that inhibits CaMKII, impairs habituation in Stentor cells. 8/n

Deepa Rajan, PhD
@deeparajan.bsky.social

We also knocked down SteCoe_6763, another calcium-binding RNA-seq candidate, using RNA interference and found that knocking down this protein accelerates habituation. We’re thinking of calling this protein “ignoramin” because getting rid of it improves learning! 9/n

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Deepa Rajan, PhD
@deeparajan.bsky.social

For decades, the prevailing story has been that we (multicellular animals) need to make new proteins to learn. Surprisingly, habituation in Stentor cells improves after treatment with drugs like puromycin that impair protein synthesis! 6/n

Deepa Rajan, PhD
@deeparajan.bsky.social

This suggests that forgetting is an active process that requires new protein synthesis. But which molecules are being synthesized/degraded? We did a series of RNA-seq and proteomics experiments to obtain molecular snapshots of cells during learning and forgetting. 7/n

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Deepa Rajan, PhD
@deeparajan.bsky.social

When Stentors receive repeated weak mechanical stimulation, however, they habituate and thus stop contracting and remain in their elongated state. Below is a video of Stentors that have become habituated after an hour of repeated stimulation. 5/n

Deepa Rajan, PhD
@deeparajan.bsky.social

If you scoop up some water from a local pond and stick it under a microscope, you might just encounter Stentor coeruleus, a unicellular organism that is capable of a type of learning called habituation. 2/n

Deepa Rajan, PhD
@deeparajan.bsky.social

Habituation is the gradual decrease in response after repeated stimulation. Humans do this, too! For example, we learn to ignore the feeling of clothes on our skin after wearing them all day. However, we have 86 billion neurons to help us learn while Stentor is a single cell! 3/n

Deepa Rajan, PhD
@deeparajan.bsky.social

If you're in SF, come celebrate St. Patrick's day with me and learn about how single cells learn! I'm giving a lecture about my research at a bar as part of the Lectures on Tap series🍻

Deepa Rajan, PhD reposted

Phil Lewis
@phillewis.bsky.social

Trump minimizes domestic abuse during a talk at the Museum of the Bible: "Things that take place in the home, they call crime ... If a man has a little fight with the wife, they say this was a crime, see?"

Deepa Rajan, PhD reposted

Orit Peleg
@oritpeleg.bsky.social

Help us record firefly flashes! 👇🙏

George Musser@georgemusser.com

Do you have fireflies in your backyard? Biologist @oritpeleg.bsky.social is collecting data! #emergence docs.google.com/forms/d/e/1F...

docs.google.comHelp us Record Firefly Flashes ✨Firefly flashes are amazing ❤️ During mating season, fireflies gather in groups and flash their species-specific flash pattern. To better understand these communication signals, we developed a method ...

Deepa Rajan, PhD reposted

Ambika Nadkarni
@biochembika.bsky.social

Our research on wound resistance in Stentor is live on bioRxiv! Tldr; we squeezed the cells through microfluidic constrictions and the formidable lead author Rajorshi Paul characterized what makes the cells get wounded!

bioRxivpreprint@biorxivpreprint.bsky.social

Characterization of cellular wound resistance in the giant ciliate Stentor coeruleus https://www.biorxiv.org/content/10.1101/2025.06.23.661154v1

Deepa Rajan, PhD
@deeparajan.bsky.social

Our paper on single-cell learning is now published in @currentbiology.bsky.social! @wallaceucsf.bsky.social sciencedirect.com/science/arti...

sciencedirect.comA receptor-inactivation model for single-celled habituation in Stentor coeruleusThe single-celled ciliate Stentor coeruleus demonstrates habituation to mechanical stimuli, but the mechanism of learning in this single cell, which l…
Deepa Rajan, PhD@deeparajan.bsky.social

How can a single cell learn without a brain or nervous system? We explore this in our new preprint with @wallaceucsf.bsky.social! We discovered that central features of learning in single cells can be accounted for by a model based on receptor inactivation bit.ly/3CDukfS 🧵 1/n

Deepa Rajan, PhD reposted

Arjun Raj
@arjunraj.bsky.social

Went to a wonderful reunion for the birthday of dear friend and colleague Gerd Blobel yesterday. In the end, it’s funny how all the papers and grants fade away and the main thing you remember are the people.

Deepa Rajan, PhD reposted

Ben Allwein
@benallwein.bsky.social

I am so proud to share a major part of my graduate school research, published today in Science, where we use cell-free replication assays and cryo-EM to describe a central mechanism of eukaryotic DNA replication: www.science.org/doi/10.1126/...

science.orgG-quadruplex–stalled eukaryotic replisome structure reveals helical inchworm DNA translocationDNA G-quadruplexes (G4s) are non–B-form DNA secondary structures that threaten genome stability by impeding DNA replication. To elucidate how G4s induce replication fork arrest, we characterized fork ...

Deepa Rajan, PhD reposted

Mark A. Hanson
@hansonmark.bsky.social

Today they went nuclear. Imagine all firefighters were told "You all still have salaries, but as of today the government will no longer pay for building maintenance, firetruck maintenance and repair, hydrant upkeep, or admin assistants." That's what they're doing to US universities.

Carl T. Bergstrom@carlbergstrom.com

8. It is difficult to overstate what a catastrophe this will be for the US research and education systems, particular in biomedical fields. It is deliberate and wanton devastation entirely out of scale with any concern about DEI activities on campuses. The goal is destroy US universities.

Deepa Rajan, PhD reposted

yoonji kim
@yoonjikim.bsky.social

HNY! In case you thought 2025 is the year of the snake, it's actually the year of the SQUID 🦑 Excited to present this new protocol paper from the @brangwynnelab.bsky.social on isolating+transfecting squid primary cells 🧫✨! Check it out here: www.biorxiv.org/content/10.1...

biorxiv.orgSquid primary cell culture as a model system and experimental toolSquid primary cells from various tissues and ages are isolated, maintained in culture, and express exogenous genes. This protocol opens up numerous opportunities in molecular biology, neuroscience, an...
Deepa Rajan, PhD
@deeparajan.bsky.social

check out my new dispatch article with @wallaceucsf.bsky.social in @currentbiology.bsky.social about cellular cognition! www.cell.com/current-biol...

cell.comCellular cognition: How single cells learn using non-neural networksSingle cells can perform surprisingly complex behaviors and computations, including primitive forms of learning like habituation. New work highlighted here uses mathematical modeling to show that relatively simple biochemical networks can recapitulate many features of habituation in animals.
Deepa Rajan, PhD@deeparajan.bsky.social

How can a single cell learn without a brain or nervous system? We explore this in our new preprint with @wallaceucsf.bsky.social! We discovered that central features of learning in single cells can be accounted for by a model based on receptor inactivation bit.ly/3CDukfS 🧵 1/n

Deepa Rajan, PhD reposted

Wallace Marshall
@wallaceucsf.bsky.social

If you are at ASCB and you missed the poster by @DeepaRajan about the molecular substrates of memory in the single cell Stentor, its not too late - you can see her talk tomorrow (Tue Dec 17) at 5:35 pm in Ballroom 20A