Nikita Frolov 🇺🇦

Feedback between F-actin organization and active stress governs criticality and energy localization in the cell cytoskeleton - Nature Physics Self-organized criticality can occur in cellular systems, but its origins remain unclear. Now it is shown that cytoskeletal criticality is influenced by the F-actin architecture and myosin active stre...

This piece of work from my PhD is FRESHLY out of the oven in
@natureportfolio.nature.com
Nature Physics! It illustrates how architecture and active stress mutually regulate Criticality and exhibit Anderson Localization-like phenomenon. www.nature.com/articles/s41...

These people are the enemy.

Kseniia Petrova is still in detention since Feb 16!

I Came to Study Aging. Now I’m Trapped in ICE Detention. www.nytimes.com/2025/05/13/o...

Hierarchical Heterogeneities in Spatio-Temporal Dynamics of the Cytoplasm Understanding of the dynamics inherent to biological matter is crucial for illuminating the physical mechanisms underlying cellular processes. In this study, we employ bright-field differential dynamic microscopy (DDM) to investigate density fluctuations inherent in a cell-free model of eukaryotic cytoplasm. Our measurements reveal subdiffusive fractional Brownian motion and non-Gaussian displacement distributions, highlighting cytoplasmic heterogeneity. We introduce an empirical model that combines fractional Brownian motion with an inverse Gaussian distribution of diffusivities to describe the observed non-Gaussianity. Validated through Monte Carlo simulations, this model allows us to estimate the fractional diffusivity and exponent effectively. By altering macromolecular composition, the addition of energy, and assembly of a cytoskeleton, we identify three independent mechanisms that result in similar fractional exponents yet distinct diffusivities. We find that energy addition leads to non-stationary dynamics, in contrast to the stationary behavior observed under passive conditions. Presence of microtubules introduces a secondary dynamical timescale, which we describe using a two-state fractional Brownian motion model to differentiate between cytosolic and microtubule network associated contributions. Our findings demonstrate the effectiveness of DDM as a label-free tool for quantifying viscoelastic and heterogeneous properties of the cytoplasm and provide insights into how physical and biochemical factors, including cytoskeletal organization, govern subcellular dynamics. ### Competing Interest Statement The authors have declared no competing interest.

New insights in to the physical properties of the 🐸 #Xenopus cytoplasm!
Great work @mctwo.bsky.social & @biswashere.bsky.social!
Together with @gucklab.bsky.social & @vasilyzaburdaev.bsky.social 😍 @mpi-scienceoflight.bsky.social
@mpiib-berlin.mpg.de

www.biorxiv.org/content/10.1...

Need some time to process all the brilliant talks and discussions to come back stronger to my research 💪🧑‍💻

It's been a very stimulating conference, many thanks to the organizers for making it possible!

It was impressive to see how people from diverse areas of expertise, working in small independent groups, pinpoint similar major questions and find common ground. Social bootstrapping in action!

She Worked in a Harvard Lab to Reverse Aging, Until ICE Jailed Her (Gift Article) President Trump’s immigration crackdown ensnared Kseniia Petrova, a scientist who fled Russia after protesting its invasion of Ukraine. She fears arrest if she is deported there.

The Americans are doing to Kseniia what the Russians did to Brittney Griner for having 0.7 grams of cannabis oil. Except no one is coming to negotiate her freedom and Harvard is sitting on their hands. I am so ashamed. Please share this story.
www.nytimes.com/2025/04/11/s...

a teddy bear is singing into a microphone while wearing a tie and hat . ALT: a teddy bear is singing into a microphone while wearing a tie and hat .

Our 11yo is telling us science dad jokes as a way to delay having to go to bed. It's working.
My favorite of the evening:
Why did the amoeba fail its math test?
....
....
because it multiplied by dividing

Today’s the kimchi night, in celebration of the KU Leuven Patron Saint’s day

From random gliding to ordered patterns.
The movie starts with microtubules gliding on a minus-end directed molecular motor.
Then, @bhagyanaths.bsky.social added a plus-end directed motor (magenta) to induce this polarity sorting and ordering process.
more details here:
www.pnas.org/doi/10.1073/...

When did the taste of the scientific community changed from liking simple elegant experiments to preferring complicated and expensive experiments?

[3/2] Returning to the office, I realize this post doesn't look attractive without any visual content. I'm fixing it urgently so you can see a fantastic movie of cdk1 activity spirals displayed by the microtubule polymerization in the frog egg cytoplasm! For clarity, we show the wave's phase as well

📢 Institut Jacques Monod Seminar

📅 January 10th
📍 Institut Jacques Monod

Invited by the Wassmann Lab, Lendert Gelens, will give an Institut Jacques Monod Seminars on the theme "Nuclei coordinate the cell cycle in space and time"

➡️ https://buff.ly/3ZM7Ykl

My New Year’s resolution is to berate myself less for things I wish I could have done better, to learn from my mistakes, and give myself more credit for the things I did well but promptly forgot/ignored because academics love to live from crisis to crisis

Spiral waves speed up cell cycle oscillations in the frog cytoplasm Spiral waves are a well-known phenomenon in excitable media, playing critical roles in biological systems such as cardiac tissues, where they are involved in arrhythmias, and in slime molds, where the...

[2/2] Using dynamical modeling, we show that such a speed-up via spiral waves is a generic property of wave propagation in an excitable medium and depends on the reaction-diffusion parameters.

Check out our preprint for more info and cool microscopy pictures 🔬🌀

[1/2] Preprint alert ‼️
When I joined @lendertgelens.bsky.social Lab, they experimentally observed atypical spiral waves in the frog egg cytoplasm, which resulted in almost twice faster cell cycle oscillations.

I got two rejections in the last two weeks before Christmas. The academy is not always a success story; it is more of an adventure journey without a map for one to find their way. I continue to follow this thought and keep on going! Happy Holidays ✌️

Hey @alisonkickuth.bsky.social , great to see you here! ✌️

More 👇

bioicons.com
scidraw.io
inkscape.org
biogdp.com
reactome.org/icon-lib

And they should all be equipped with a blackboard like those at the Erwin Schrödinger Institute in Vienna (couldn’t help taking a picture 😅). #BringYourOwnChalk

*clue

I guess regulation is not necessarily conscious. For example, in cells, it could be a “programmed” chain of biological reactions in response to some external or internal mechanical or chemical cue.
In turn, consciousness can provide a different, higher-level regulation.

It's okay to say 'I don't know', particularly if you don't know.

Force-transducing molecular ensembles at growing microtubule tips control mitotic spindle size - Nature Communications Forces that lead to stable bipolar organization of mitotic spindles are poorly understood. Here the authors show that growing interpolar microtubules make a unique contribution to the overall force ba...

2/2 In their latest paper, the Molodtsov lab revealed a minimal model allowing for spindle bipolarity, in which the force generated by growing microtubules balances the minus-end-directed motion produced by the molecular motor.

www.nature.com/articles/s41...

1/2 Cool paper alert 🚨 Despite extensive research on mitotic spindle formation and the discovery of most molecules involved, what provides its stable bipolarity is still puzzling.

Hi to everyone in #ScienceSky! I’m happy to see the community migration and to find most of my Twitter contacts hire in BlueSky 🖐️🤝

Beautiful! So, the polymerization waves stabilize the cells and center them around spiral tips due to the fast rotations?

Wow, so cool almost-textbook spirals!