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

Für Ankündigungen und Benachrichtigungen bitte in dem Moodle-Kurs “ZBP-Kolloquium” registrieren.

Zukünftige Vorträge

ZBP Kolloquium

Prof. Dr. Nadja Tarakina (INM-Leibniz Institute for New Materials)
Titel: Electron microscopy of soft functional materials: challenges and opportunities
Zeit: 14 Uhr c.t. (Tee/Kaffee ab 14:00)
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)
Gastgeber: Prof. Franziska Lautenschläger

Abstract: Soft functional materials (polymers, colloids, biomaterials, gels, liquid crystals, etc.) are crucial components of many everyday products and are an indispensable part of high-tech applications. Their mesoscale (nanoscale to microscale) structure, morphology and composition dictate their properties. While electron microscopy is one of the most powerful tools to characterise materials at atomic and nanoscales, its application to soft materials is challenging due to their inherent beam sensitivity, low contrast and intrinsic entropic nature. In my talk I will give an overview of research activities at my department in the application of advanced electron microscopy methodologies (low-dose HR-TEM, energy filtered electron radial distribution function analysis, EXELFS, LC-TEM, etc.) to the characterisation of soft functional materials and their interfaces (e.g. carbon nitride photocatalyst heterojunctions, colloidal particles in liquids, single-atom catalysts, etc.) and present future opportunities in this research direction. 
 

ZBP Kolloquium

Prof. Dr. Anupam Sengupta (University of Luxembourg)
Titel: Microbes on the move: from aquatic ecosystems to tumorigenic environments
Zeit: 14 Uhr c.t. (Tee/Kaffee ab 14:00)
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)
Gastgeber: Prof. Christian Wagner

Abstract: Microbes constitute an interconnected continuum across One Earth, linking aquatic ecosystems and terrestrial environments to the human microbiome through shared evolutionary histories, biogeochemical functions, and dynamic exchanges that collectively shape planetary and human health. A defining feature of microbial life is its extraordinary capacity to sense, respond to, and adapt rapidly to environmental cues across wide temporal and spatial scales, from fluctuations in climatic conditions to exposure to anthropogenic stresses. Despite decades of study, a comprehensive framework capable of explaining and predicting these adaptive dynamics, continues to captivate – and elude – biologists, physicists, and engineers alike. Research in my team seeks to address this gap by integrating concepts from physics and bioengineering with micro- and cell biology. Leveraging advanced 3D microfabrication, automation, quantitative imaging, and machine-learning–based analysis, we investigate how microbes, as active living systems, couple individual behaviors with collective organization. Drawing on recent works across diverse biological contexts—including aquatic microalgae, pathogenic biofilms, and bacteria-associated tumors— I will demonstrate how microbes adapt to environmental perturbations and, when necessary, actively remodel their surroundings to optimize fitness. A focal example is Lago di Cadagno, a Swiss Alpine lake where our decade-long research has revealed how spatial organization and metabolic activity of sulfur bacteria emerge from a delicate interplay of collective dynamics, physical gradients and biological constraints. In a seemingly distant context, I will present how anoxic microbes, including sulfur bacteria, influence tumorigenesis in humans. While the recent inclusion of the microbiome among the Hallmarks of Cancer highlights the importance of bacteria in tumor progression, prevailing molecular approaches have largely overlooked the underlying biophysical mechanisms. Our work introduces a data-rich, mechanistic paradigm that complements molecular biology, and opens translational avenues in bioremediation and the management of bacteria-associated cancers, some of which I will highlight in my concluding notes.

ZBP Kolloquium

Prof. Dr. Jörg Renkawitz (LMU München)
Titel: Centrosome integrity controls microtubule network architecture and cellular pathfinding
Zeit: 14 Uhr c.t. (Tee/Kaffee ab 14:00)
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)
Gastgeber: Prof. Franziska Lautenschläger

Abstract: The centrosome orchestrates the microtubule network by nucleating and anchoring radial microtubule arrays that coordinate intracellular transport. At the same time, mechanical stresses from the microenvironment and changes in cellular shape compress and bend microtubules, raising the question of how the membrane-less centrosome withstands mechanical forces.

In recent work (Schmitt et al., Science Advances, 2025), we discovered that migration through confining three-dimensional microenvironments mechanically deforms the centrosome, rendering it susceptible to breakage. We identify a protective pathway in which the kinase Dyrk3 cooperates with the centrosomal linker protein cNAP1 to preserve centrosome cohesion and resist actomyosin force-induced fragmentation.

Centrosome fracturing leads to spatially separated, coexisting microtubule-organizing centers (MTOCs), thereby generating competing microtubule networks within a single cell. Live-cell imaging of competing MTOCs upon centrosome fracture demonstrates delayed path decisions during cell migration, leading to the entanglement of rapidly migrating immune cells and slow-migrating fibroblasts in three-dimensional microenvironments. In contrast, cells lacking centrioles but maintaining a single functional MTOC retain efficient directional decision-making. Thus, it is not centriole loss, but the coexistence of multiple functional MTOCs that impairs efficient cell migration. These results establish that it is critical for motile cells to maintain their microtubule architecture from a single microtubule-organising centre. More broadly, our findings demonstrate the importance of microtubule-based architecture in highly dynamic cells with complex shapes.

Further, I will present new findings demonstrating how the spatiotemporal dynamics of the microtubule network architecture are critical for cell migration in complex three-dimensional microenvironments. 

ZBP Kolloquium

Dr. Stephanie Möllmert (Max-Planck-Zentrum für Physik und Medizin, Max Planck Institute for the Science of Light, Erlangen)
Titel: From Neural Tissue to the Reproductive Tract: Quantitative Mechanics Across Living System
Zeit: 14 Uhr c.t. (Tee/Kaffee ab 14:00)
Ort: Campus SB, Gebäude C6 4, Raum 0.09 (Hörsaal II)
Gastgeber: Prof. Franziska Lautenschläger

Abstract: Mechanical forces are integral to tissue physiology: cells sense and generate forces, and tissue material state evolves during development, regeneration, and disease. Yet quantitative measurements of viscoelasticity in intact, living tissues remain scarce because these systems are heterogeneous, actively remodeling, and difficult to probe without perturbation. In this colloquium, I will present our strategy to quantify tissue mechanics across scales by combining atomic force microscopy (AFM)-based indentation, Brillouin microscopy, and histological readouts that anchor mechanical parameters to composition and structure. I will begin with nervous tissue mechanics, drawing on studies of developing, injured, and regenerating spinal cord as well as layered neural tissues. In the second part, I will extend these concepts to reproductive mechanics, focusing on the murine oviduct as a confined, cyclically active environment that supports fertilization and early embryo transport. I will present first segment- and cycle-resolved measurements that constrain physiological mechanical parameter ranges compatible with transport, show how these ranges shift in aberrant conditions, and discuss how quantitative mechanics can inform mechanistic models and more faithful ex vivo reproductive platforms.

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Vergangene Vorträge

ZBP Kolloquium

Prof. Dr. Carl Modes (Max Planck Institute of Molecular Cell Biology and Genetics, Dresden)
Titel: Programming Biological Shapes: Morphogenesis in an Active Solid
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: Understanding how epithelial sheets of cells robustly and reliably adopt complex shapes during animal development remains a key open problem of developmental biology and tissue mechanics. Classically, cortical contractility of the apical surface of these cells generating local bending moments in an effectively fluid tissue has been the go-to theoretical picture for such problems. However, many morphogenetic events are not well explained under this framework. We hypothesize that collective, in-plane active cell behaviours could instead generate effective spontaneous strains in a solid tissue and in so doing drive stable shape outcomes. We explore these ideas and their consequences in a series of lower dimensional and/or simplified arenas, from a quasi-1d spontaneous strain buckling instability model of the Drosophila cephalic furrow, to how actively driven neighbour rearrangements in vertex models can give rise both to entropic forces in the tissue and locally establish coarse-grained spontaneous strains at steady state.  We then turn to a full-blown 3D problem where, together with experimental collaborators, we show that active, in-plane cellular behaviours create the spontaneous strains that ultimately shape the Drosophila wing disc pouch during the dramatic morphogenetic event known as eversion. Taken together, these findings establish active, in-plane, solid shape programming as a potentially general mechanism for animal tissue morphogenesis.

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: Dr. Philipp Hövel

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.

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. 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