TY - JOUR A1 - Thormann, Kai M. A1 - Beta, Carsten A1 - Kuhn, Marco J. T1 - Wrapped up BT - the motility of polarly flagellated bacteria JF - Annual review of microbiology N2 - A huge number of bacterial species are motile by flagella, which allow them to actively move toward favorable environments and away from hazardous areas and to conquer new habitats. The general perception of flagellum-mediated movement and chemotaxis is dominated by the Escherichia coli paradigm, with its peritrichous flagellation and its famous run-and-tumble navigation pattern, which has shaped the view on how bacteria swim and navigate in chemical gradients. However, a significant amount-more likely the majority-of bacterial species exhibit a (bi)polar flagellar localization pattern instead of lateral flagella. Accordingly, these species have evolved very different mechanisms for navigation and chemotaxis. Here, we review the earlier and recent findings on the various modes of motility mediated by polar flagella. KW - flagella KW - chemotaxis KW - bacterial swimming KW - flagellar wrapping KW - navigation Y1 - 2022 U6 - https://doi.org/10.1146/annurev-micro-041122-101032 SN - 0066-4227 SN - 1545-3251 VL - 76 SP - 349 EP - 367 PB - Annual Reviews Inc. CY - Palo Alto ER - TY - JOUR A1 - Yochelis, Arik A1 - Flemming, Sven A1 - Beta, Carsten T1 - Versatile patterns in the actin cortex of motile cells BT - self-organized pulses can coexist with macropinocytic ring-shaped waves JF - Physical review letters N2 - Self-organized patterns in the actin cytoskeleton are essential for eukaryotic cellular life. They are the building blocks of many functional structures that often operate simultaneously to facilitate, for example, nutrient uptake and movement of cells. However, identifying how qualitatively distinct actin patterns can coexist remains a challenge. Using bifurcation theory of a mass conserved activator-inhibitor system, we uncover a generic mechanism of how different actin waves-traveling waves and excitable pulses- organize and simultaneously emerge. Live-cell imaging experiments indeed reveal that narrow, planar, and fast-moving excitable pulses may coexist with ring-shaped macropinocytic actin waves in the cortex of motile amoeboid cells. Y1 - 2022 U6 - https://doi.org/10.1103/PhysRevLett.129.088101 SN - 0031-9007 SN - 1079-7114 VL - 129 IS - 8 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Lepro, Valentino A1 - Großmann, Robert A1 - Panah, Setareh Sharifi A1 - Nagel, Oliver A1 - Klumpp, Stefan A1 - Lipowsky, Reinhard A1 - Beta, Carsten T1 - Optimal cargo size for active diffusion of biohybrid microcarriers JF - Physical Review Applied N2 - As society paves its way towards device miniaturization and precision medicine, microscale actuation and transport become increasingly prominent research fields with high impact in both technological and clinical contexts. In order to accomplish movement of micron-sized objects towards specific target sites, active biohybrid transport systems, such as motile living cells that act as smart biochemically powered microcarriers, have been suggested as an alternative to synthetic microrobots. Inspired by the motility of leukocytes, we propose the amoeboid crawling of eukaryotic cells as a promising mechanism for transport of micron-sized cargoes and present an in-depth study of this type of composite active matter. Its transport properties result from the interactions of an active element (cell) and a passive one (cargo) and reveal an optimal cargo size that enhances the locomotion of the load-carrying cells, even exceeding their motility in the absence of cargo. The experimental findings are rationalized in terms of a biohybrid active particle model that describes the emergent cell-cargo dynamics and enables us to derive the long-time diffusive transport of amoeboid microcarriers. As amoeboid locomotion is commonly observed for mammalian cells such as leukocytes, our results lay the foundations for the study of transport performance of other medically relevant cell types and for extending our findings to more advanced transport tasks in complex environments, such as tissues. Y1 - 2022 U6 - https://doi.org/10.1103/PhysRevApplied.18.034014 SN - 2331-7019 VL - 18 IS - 3 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Pfeifer, Veronika A1 - Beier, Sönke A1 - Alirezaeizanjani, Zahra A1 - Beta, Carsten T1 - Role of the two flagellar stators in swimming motility of pseudomonas putida JF - mBio N2 - In the soil bacterium Pseudomonas putida, the motor torque for flagellar rotation is generated by the two stators MotAB and MotCD. Here, we construct mutant strains in which one or both stators are knocked out and investigate their swimming motility in fluids of different viscosity and in heterogeneous structured environments (semisolid agar). Besides phase-contrast imaging of single-cell trajectories and spreading cultures, dual-color fluorescence microscopy allows us to quantify the role of the stators in enabling P. putida's three different swimming modes, where the flagellar bundle pushes, pulls, or wraps around the cell body. The MotAB stator is essential for swimming motility in liquids, while spreading in semisolid agar is not affected. Moreover, if the MotAB stator is knocked out, wrapped mode formation under low-viscosity conditions is strongly impaired and only partly restored for increased viscosity and in semisolid agar. In contrast, when the MotCD stator is missing, cells are indistinguishable from the wild type in fluid experiments but spread much more slowly in semisolid agar. Analysis of the microscopic trajectories reveals that the MotCD knockout strain forms sessile clusters, thereby reducing the number of motile cells, while the swimming speed is unaffected. Together, both stators ensure a robust wild type that swims efficiently under different environmental conditions. IMPORTANCE Because of its heterogeneous habitat, the soil bacterium Pseudomonas putida needs to swim efficiently under very different environmental conditions. In this paper, we knocked out the stators MotAB and MotCD to investigate their impact on the swimming motility of P. putida. While the MotAB stator is crucial for swimming in fluids, in semisolid agar, both stators are sufficient to sustain a fast-swimming phenotype and increased frequencies of the wrapped mode, which is known to be beneficial for escaping mechanical traps. However, in contrast to the MotAB knockout, a culture of MotCD knockout cells spreads much more slowly in the agar, as it forms nonmotile clusters that reduce the number of motile cells. Because of its heterogeneous habitat, the soil bacterium Pseudomonas putida needs to swim efficiently under very different environmental conditions. In this paper, we knocked out the stators MotAB and MotCD to investigate their impact on the swimming motility of P. putida. KW - bacterial swimming KW - stators KW - structured environments Y1 - 2022 U6 - https://doi.org/10.1128/mbio.02182-22 SN - 2150-7511 VL - 13 IS - 6 PB - American Society for Microbiology CY - Washington ER - TY - GEN A1 - Alirezaeizanjani, Zahra A1 - Großmann, Robert A1 - Pfeifer, Veronika A1 - Hintsche, Marius A1 - Beta, Carsten T1 - Chemotaxis strategies of bacteria with multiple run modes T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Bacterial chemotaxis-a fundamental example of directional navigation in the living world-is key to many biological processes, including the spreading of bacterial infections. Many bacterial species were recently reported to exhibit several distinct swimming modes-the flagella may, for example, push the cell body or wrap around it. How do the different run modes shape the chemotaxis strategy of a multimode swimmer? Here, we investigate chemotactic motion of the soil bacterium Pseudomonas putida as a model organism. By simultaneously tracking the position of the cell body and the configuration of its flagella, we demonstrate that individual run modes show different chemotactic responses in nutrition gradients and, thus, constitute distinct behavioral states. On the basis of an active particle model, we demonstrate that switching between multiple run states that differ in their speed and responsiveness provides the basis for robust and efficient chemotaxis in complex natural habitats. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1418 KW - instability KW - flagellum KW - exploit KW - time Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-519098 SN - 1866-8372 IS - 1418 ER - TY - JOUR A1 - Pasemann, Gregor A1 - Flemming, Sven A1 - Alonso, Sergio A1 - Beta, Carsten A1 - Stannat, Wilhelm T1 - Diffusivity estimation for activator-inhibitor models BT - theory and application to intracellular dynamics of the actin cytoskeleton JF - Journal of nonlinear science N2 - A theory for diffusivity estimation for spatially extended activator-inhibitor dynamics modeling the evolution of intracellular signaling networks is developed in the mathematical framework of stochastic reaction-diffusion systems. In order to account for model uncertainties, we extend the results for parameter estimation for semilinear stochastic partial differential equations, as developed in Pasemann and Stannat (Electron J Stat 14(1):547-579, 2020), to the problem of joint estimation of diffusivity and parametrized reaction terms. Our theoretical findings are applied to the estimation of effective diffusivity of signaling components contributing to intracellular dynamics of the actin cytoskeleton in the model organism Dictyostelium discoideum. KW - Parametric drift estimation KW - Stochastic reaction– diffusion KW - systems KW - Maximum likelihood estimation KW - Actin cytoskeleton dynamics Y1 - 2021 U6 - https://doi.org/10.1007/s00332-021-09714-4 SN - 0938-8974 SN - 1432-1467 VL - 31 IS - 3 PB - Springer CY - New York ER - TY - JOUR A1 - Heinsohn, Natascha Katharina A1 - Niedl, Robert Raimund A1 - Anielski, Alexander A1 - Lisdat, Fred A1 - Beta, Carsten T1 - Electrophoretic mu PAD for purification and analysis of DNA samples JF - Biosensors : open access journal N2 - In this work, the fabrication and characterization of a simple, inexpensive, and effective microfluidic paper analytic device (mu PAD) for monitoring DNA samples is reported. The glass microfiber-based chip has been fabricated by a new wax-based transfer-printing technique and an electrode printing process. It is capable of moving DNA effectively in a time-dependent fashion. The nucleic acid sample is not damaged by this process and is accumulated in front of the anode, but not directly on the electrode. Thus, further DNA processing is feasible. The system allows the DNA to be purified by separating it from other components in sample mixtures such as proteins. Furthermore, it is demonstrated that DNA can be moved through several layers of the glass fiber material. This proof of concept will provide the basis for the development of rapid test systems, e.g., for the detection of pathogens in water samples. KW - microfluidic paper analytic device (mu PAD) KW - patterning glass microfiber KW - fiber-electrophoresis chip KW - DNA KW - imprinted electrodes KW - cross layer chip KW - polymerase chain reaction (PCR) KW - purification Y1 - 2022 U6 - https://doi.org/10.3390/bios12020062 SN - 2079-6374 VL - 12 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - Yochelis, Arik A1 - Beta, Carsten A1 - Gov, Nir S. T1 - Excitable solitons BT - annihilation, crossover, and nucleation of pulses in mass-conserving activator-inhibitor media JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - Excitable pulses are among the most widespread dynamical patterns that occur in many different systems, ranging from biological cells to chemical reactions and ecological populations. Traditionally, the mutual annihilation of two colliding pulses is regarded as their prototypical signature. Here we show that colliding excitable pulses may exhibit solitonlike crossover and pulse nucleation if the system obeys a mass conservation constraint. In contrast to previous observations in systems without mass conservation, these alternative collision scenarios are robustly observed over a wide range of parameters. We demonstrate our findings using a model of intracellular actin waves since, on time scales of wave propagations over the cell scale, cells obey conservation of actin monomers. The results provide a key concept to understand the ubiquitous occurrence of actin waves in cells, suggesting why they are so common, and why their dynamics is robust and long-lived. Y1 - 2020 U6 - https://doi.org/10.1103/PhysRevE.101.022213 SN - 2470-0045 SN - 2470-0053 VL - 101 IS - 2 PB - American Physical Society CY - Melville, NY ER - TY - JOUR A1 - Moldenhawer, Ted A1 - Moreno, Eduardo A1 - Schindler, Daniel A1 - Flemming, Sven A1 - Holschneider, Matthias A1 - Huisinga, Wilhelm A1 - Alonso, Sergio A1 - Beta, Carsten T1 - Spontaneous transitions between amoeboid and keratocyte-like modes of migration JF - Frontiers in Cell and Developmental Biology N2 - The motility of adherent eukaryotic cells is driven by the dynamics of the actin cytoskeleton. Despite the common force-generating actin machinery, different cell types often show diverse modes of locomotion that differ in their shape dynamics, speed, and persistence of motion. Recently, experiments in Dictyostelium discoideum have revealed that different motility modes can be induced in this model organism, depending on genetic modifications, developmental conditions, and synthetic changes of intracellular signaling. Here, we report experimental evidence that in a mutated D. discoideum cell line with increased Ras activity, switches between two distinct migratory modes, the amoeboid and fan-shaped type of locomotion, can even spontaneously occur within the same cell. We observed and characterized repeated and reversible switchings between the two modes of locomotion, suggesting that they are distinct behavioral traits that coexist within the same cell. We adapted an established phenomenological motility model that combines a reaction-diffusion system for the intracellular dynamics with a dynamic phase field to account for our experimental findings. KW - cell migration KW - amoeboid motility KW - keratocytle-like motility KW - modes of KW - migration KW - D. discoideum KW - actin dynamics Y1 - 2022 U6 - https://doi.org/10.3389/fcell.2022.898351 SN - 2296-634X VL - 10 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Moreno, Eduardo A1 - Großmann, Robert A1 - Beta, Carsten A1 - Alonso, Sergio T1 - From single to collective motion of social amoebae BT - a computational study of interacting cells JF - Frontiers in physics N2 - The coupling of the internal mechanisms of cell polarization to cell shape deformations and subsequent cell crawling poses many interdisciplinary scientific challenges. Several mathematical approaches have been proposed to model the coupling of both processes, where one of the most successful methods relies on a phase field that encodes the morphology of the cell, together with the integration of partial differential equations that account for the polarization mechanism inside the cell domain as defined by the phase field. This approach has been previously employed to model the motion of single cells of the social amoeba Dictyostelium discoideum, a widely used model organism to study actin-driven motility and chemotaxis of eukaryotic cells. Besides single cell motility, Dictyostelium discoideum is also well-known for its collective behavior. Here, we extend the previously introduced model for single cell motility to describe the collective motion of large populations of interacting amoebae by including repulsive interactions between the cells. We performed numerical simulations of this model, first characterizing the motion of single cells in terms of their polarity and velocity vectors. We then systematically studied the collisions between two cells that provided the basic interaction scenarios also observed in larger ensembles of interacting amoebae. Finally, the relevance of the cell density was analyzed, revealing a systematic decrease of the motility with density, associated with the formation of transient cell clusters that emerge in this system even though our model does not include any attractive interactions between cells. This model is a prototypical active matter system for the investigation of the emergent collective dynamics of deformable, self-driven cells with a highly complex, nonlinear coupling of cell shape deformations, self-propulsion and repulsive cell-cell interactions. Understanding these self-organization processes of cells like their autonomous aggregation is of high relevance as collective amoeboid motility is part of wound healing, embryonic morphogenesis or pathological processes like the spreading of metastatic cancer cells. KW - cell motility KW - cell polarity KW - reaction-diffusion models KW - cell-cell KW - interactions KW - phase field model KW - collective motion KW - active matter Y1 - 2022 U6 - https://doi.org/10.3389/fphy.2021.750187 SN - 2296-424X VL - 9 PB - Frontiers Media CY - Lausanne ER -