Multiciliated sensory cells in pressure and gravity sensation
The Biophysics of Motile Cilia – from Structure to Function
830. WE-Heraeus-Seminar, Bad Honnef
March 30 - April 2, 2025
Centre for Organismal Studies, Heidelberg University
@jekely@biologists.social
Ciliated zooplankton larvae
Platynereis dumerilii
- breeding culture
- genome sequence
- microinjection, transgenesis
- neuron-specific promoters
- knock-out lines
- neuronal connectome
- neuronal activity imaging
Multiciliated cells form ciliary bands
- basal-body spacing: 0.35-0.55 μm
Metachronal waves
- metachronal waves
- large-scale coordination of cilia
- steric interactions dominate
Precise orientation of multiciliary arrays
expansion microscopy
Whole-body annotation of all ciliary basal bodies
Whole-body annotation of all ciliary basal bodies
- ~10,000 motile cilia
- high degree of left-right symmetry
- 3D additive manufacturing from anterior to posterior of the cell
Whole-body annotation of all ciliary basal bodies
Synaptic connectome
Phototaxis
Helical swimming, sensing and turning are tightly linked
Whole-body coordination of cilia
Whole-body coordination of cilia
Pressure response in Platynereis larvae
Precise control of pressure in the pressure chamber
Pressure response is graded
Swimming speed increases, trajectories straighten
ctr
pressure
Ciliary beating increases under pressure
Which cells respond to pressure?
Microscopy pressure chamber 
Calcium imaging 
Pressure is sensed by photoreceptors with ramified cilia
Photoreceptor responses to pressure are graded
Defects of pressure response in c-opsin1 mutants
Reduced ciliary compartment in c-opsin1 mutants
Defects of ciliary ultrastructure in c-opsin1 mutants
Circuit of ciliary photoreceptors
Pressure increases ciliary beating through serotonergic cells
Mechanism of barotaxis
The ctenophore gravisensory organ
The ctenophore gravisensory organ
Balancer – a bundle of cilia supporting a statolyth
The beating of balancer cilia is coordinated by a nerve net
Synchronisation of balancer cilia
Conntectome of the ctenophore balancer
- global neuronal coordination
- synchronisation of arrests
- synchronisation of re-beat
- synchronisation of beat frequency
Acknowledgements
Lab members
- Sanja Jasek
- Alexandra Kerbl
- Emily Savage
- Simone Wolters
- Lara Keweloh
- Kevin Urbansky
- Karel Mocaer
- David Hug
- Benedikt Dürr
- Ira Maegele
- Emelie Brodrick (Exeter)
Alumni
- Kei Jokura (NIBB, Okazaki)
Facilities
- EM Core Facility
- Réza Shahidi
- Charlotta Funaya
- Nikon Imaging Centre
- Ulrike Engel
