The Physics of Life (PoL) PhD and Postdoc seminar is a meeting where PoL early career scientists present their research to their peers. All are welcome!
The seminar consists of two short talks by PhD students and/or Postdocs, each followed by a discussion in which speaker and attendants can exchange ideas, engage in scientific discussions and network with their fellow young scientists.
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The talks:
Lara Köhler (Brugués Group) – Flow-wave coupling synchronizes oscillations in growing active matter
Oscillatory biochemical signals and mechanical forces must coordinate robustly during development, yet the principles governing their mutual coupling remain poorly understood. In syncytial embryos and cell-free extracts, mitotic waves propagate across millimeter scales while simultaneously generating cytoplasmic flows, suggesting a two-way interaction between chemical oscillators and mechanics. Here, we combine experiments in Xenopus Laevis cytoplasmic extracts with a minimal particle-based model to reveal a mechanochemical feedback that stabilizes phase wave propagation. In contrast to previous models of oscillatory active matter, an asymmetric size cycle, slow growth and rapid shrinkage, combined with size-dependent mechanical interactions generates a net particle displacement and flows aligned with the wave direction, which in turn drive a synchronization transition. Our results show that mechanical forces actively maintain the coherence of biochemical waves, providing a general mechanism for long-range order in oscillating active matter.
Marina Marchenko (Ebisuya Group) – Synthetic lumen rounding directs neural progenitor division mode
Although function often follows form, the causal role of tissue geometry is difficult to disentangle in complex embryonic development. Brain organoids generated using diverse protocols and species display striking morphological variability, particularly in lumen shape; however, whether and how lumen geometry influences neural development remains unclear. In my research, I manipulate lumen sphericity in brain organoids by acutely inducing apical constriction and reveal its impact on the division orientation of apical progenitors. Rapid protein stabilization or optogenetic reconstitution of the apical constriction regulator Shroom3 induces pronounced lumen rounding, accompanied by a reduction in apical surface area. In organoids with rounded lumens, apical progenitor divisions shift toward horizontal cleavage planes compared with control organoids, consistent with geometric constraints from the reduced apical surface. These findings identify lumen geometry as an instructive regulator of progenitor division mode and lineage progression during early brain development. I recently defended my PhD thesis, and I also want to share my PhD experience during this talk.
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For those who cannot join on site, a Zoom option will be available for internal staff.