ZBP-Kolloquium

Das Kollioquium des Zentrums für Biophysik findet während der Vorlesungszeit in monatlichen Rhythmus statt. 

  • Zeit: Donnerstags von 14 bis 16 Uhr
  • Ort: C6 4, Hörsaal II

Zukünftige Vorträge

ZBP Kolloquium

Prof. Dr. Emanuel Schneck (TU Darmstadt)
Titel: Combining X-Ray Scattering and Molecular Simulations for the Study of Lipid and Surfactant Layers at Air/Water Interfaces
Zeit: 14 Uhr c.t. (Tee/Kaffee ab 14:00)
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)
Gastgeber: Prof. Jochen Hub

Abstract: Lipids and surfactants are important building blocks of biological and technological soft matter, respectively. Understanding their structure and (thermo-) dynamics therefore holds much promise for future applications. Recent progress in experimental characterization methods and simulations has been facilitating combined experimental/theoretical investigations. Here, we integrate surface-sensitive x-ray scattering  techniques with atomistic moloecular dynamics simulations for the comprehensive characterization and description of lipid and surfactant layers at air/water interfaces. This approach serves for the interpretation of experimental results and for the validation and optimization of simulation force fields.

ZBP Kolloquium

Prof. Dr. Joachim O. Rädler (LMU München)
Titel: pH-Dependent Mesophases Determine Lipid Nanoparticle Function: Toward Controlled Gene Expression and Cellular Reprogramming
Zeit: 14 Uhr c.t. (Tee/Kaffee ab 14:00)
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)
Gastgeber: Prof. Heiko Rieger

Abstract: Lipid nanoparticles (LNPs) are the leading platform for nucleic acid delivery. We show that pH-driven structural transitions of cationic ionizable lipids (CILs)—from inverse cubic (Fd3m) to inverse hexagonal (HII) phases—exist in model systems and appear to be correlated with gene delivery efficiency. Using high-resolution small-angle X-ray scattering, live-cell imaging on single-cell arrays (LISCA) and mathematical modeling we establish self-regulated and noise-buffered gene expression. We apply LNP delivery to transiently reprogram migratory phenotypes as a powerful tool for synthetic biology.

Müller, J.A., N. Schäffler, T. Kellerer, G. Schwake, T.S. Ligon, and J.O. Rädler. 2024. Kinetics of RNA-LNP delivery and protein expression. European Journal of Pharmaceutics and Biopharmaceutics. 197:114222.
J. Philipp, A. ... L. Lindfors and J.O. Rädler. 2023. pH-dependent structural transitions in cationic ionizable lipid mesophases are critical for lipid nanoparticle function,PNAS Vol. 120 No. 50 e2310491120.

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Vergangene Vorträge

ZBP Kolloquium

Prof. Dr. Stefan Diez (TU Dreden)
Titel: Gliding Motion of Diatoms: Of Motors, Filaments and Complex Motility Patterns
Zeit: 14 Uhr c.t. (Tee/Kaffee ab 14:00)
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)

Abstract: Diatoms are one of the few eukaryotic organisms capable of gliding motility, characterized by rapid movement and quasi-instantaneous directional reversals. While previous models have proposed an actomyosin system as the force-generating mechanism, direct evidence for the involvement of actin and myosin in diatom gliding has been lacking. Additionally, the ability of rigid-walled diatoms to dynamically reorient and navigate complex environments has remained poorly understood. Here, we show that raphe-associated actin bundles, essential for diatom gliding, do not exhibit directional turnover, indicating that actin dynamics are not directly involved in force generation. Instead, we identify four raphid diatom-specific myosins (CaMyo51A-D) in Craspedostauros australis through phylogenomic analysis. Of these, only CaMyo51B-D demonstrate coordinated movement during gliding, highlighting their role in force production. Moreover, we demonstrate that diatoms achieve diverse motility patterns by dynamically switching between one- and two-raphe contact gliding, a process driven by variations in local raphe curvature and cell-substrate attachment dynamics. This dynamic-raphe-switching mechanism allows for rapid changes in path curvature and cell reorientation, particularly pronounced in smaller cells due to their increased local raphe curvature. Our findings provide novel insights into the molecular and biomechanical principles governing diatom motility, revealing how motor proteins, filament architecture, and substrate interactions coordinate to produce complex gliding behaviors.

M. G. Davutoglu, V. F. Geyer, Lukas Niese, J. R. Soltwedel, M. L. Zoccoler, R. Haase, N. Kröger, S. Diez, N. Poulsen. Gliding motility of the diatom Craspedostauros australis correlates with the intracellular movement of raphid-specific myosins. Communications Biology 7, 1187 (2024). 

S. Golfier, V. F. Geyer, N. Poulsen, S. Diez, Dynamic switching of cell-substrate contact sites allows gliding diatoms to modulate the curvature of their paths. bioRxiv 2025.03.18.643962  (2025).
 

ZBP Kolloquium

Prof. Dr. T.-Y. Dora Tang. (Universität des Saarlandes)
Titel: From molecules to life: building living systems from scratch
Zeit: 14 Uhr c.t. (Tee/Kaffee ab 14:00)
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)

Abstract: One of the goals of bottom-up synthetic biology is to build living cells from scratch. Biology is well equipped in exploiting a large number of out-of-equilibrium processes to support life. A complete understanding of these mechanisms is still in its infancy due to the complexity and number of the individual components involved in the reactions. However, a bottom-up approach allows us to replicate key biological processes using a small number of basic building blocks. Moreover, this methodology has the added advantage that properties and characteristics of the artificial cell can be readily tuned and adapted. 

In this talk, I will provide an overview of the strategies we adopt in our lab to build living systems from scratch that rely on reactions, compartments and communication as the defining feature to support out-of-equilibrium behaviour. Specifically, I will talk about the design and synthesis of artificial cells based on liquid-liquid phase separation (coacervation) and hydrophobic effects such as lipid vesicles and proteinosomes and describe how these compartments may be used as platforms for implementing life-like behaviours including: oscillations and communication. I propose that our bottom-up approaches are effective in establishing living systems from scratch and in doing so provide unique model systems that can help to unravel the physico-chemical principles of living systems. 

Prof. Dr. François Nédélec (Sainsbury Laboratory University of Cambridge, United Kingdom)
Titel: Simple Chromosome Partioning Mechanisms and a Mitotic Spindle
Zeit: 16 Uhr c.t.
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)
Gastgeber: Dr. Philipp Hövel

Prof. Dr. Nicolas Vandewalle. (University of Liege)
Titel: Exploiting capillary interactions for assembling meso-structures
Zeit: 16 Uhr c.t.
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)
Gastgeber: Prof. Christian Wagner