Janshoff, Andreas

[["dc.bibliographiccitation.artnumber","051132"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW E"],["dc.bibliographiccitation.volume","82"],["dc.contributor.author","Diezemann, Gregor"],["dc.contributor.author","Schlesier, Thomas"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Janshoff, Andreas"],["dc.date.accessioned","2018-11-07T08:36:38Z"],["dc.date.available","2018-11-07T08:36:38Z"],["dc.date.issued","2010"],["dc.description.abstract","We present a detailed analysis of two-state trajectories obtained from force-clamp spectroscopy (FCS) of reversibly bonded systems. FCS offers the unique possibility to vary the equilibrium constant in two-state kinetics, for instance, the unfolding and refolding of biomolecules, over many orders of magnitude due to the force dependence of the respective rates. We discuss two different kinds of counting statistics, the event counting usually employed in the statistical analysis of two-state kinetics and additionally the so-called cycle counting. While in the former case all transitions are counted, cycle counting means that we focus on one type of transitions. This might be advantageous in particular if the equilibrium constant is much larger or much smaller than unity because in these situations the temporal resolution of the experimental setup might not allow to capture all transitions of an event-counting analysis. We discuss how an analysis of FCS data for complex systems exhibiting dynamic disorder might be performed yielding information about the detailed force dependence of the transition rates and about the time scale of the dynamic disorder. In addition, the question as to which extent the kinetic scheme can be viewed as a Markovian two-state model is discussed."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft [SFB 625]"],["dc.identifier.doi","10.1103/PhysRevE.82.051132"],["dc.identifier.isi","000286736200002"],["dc.identifier.pmid","21230462"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/18362"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1539-3755"],["dc.title","Statistics of reversible bond dynamics observed in force-clamp spectroscopy"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","European Biophysics Journal"],["dc.contributor.author","Witt, Hannes"],["dc.contributor.author","Savić, Filip"],["dc.contributor.author","Verbeek, Sarah"],["dc.contributor.author","Dietz, Jörn"],["dc.contributor.author","Tarantola, Gesa"],["dc.contributor.author","Oelkers, Marieelen"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Janshoff, Andreas"],["dc.date.accessioned","2021-04-14T08:29:19Z"],["dc.date.available","2021-04-14T08:29:19Z"],["dc.date.issued","2021"],["dc.identifier.doi","10.1007/s00249-020-01490-5"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/82863"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.relation.eissn","1432-1017"],["dc.relation.issn","0175-7571"],["dc.title","Membrane fusion studied by colloidal probes"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2508"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Soft Matter"],["dc.bibliographiccitation.lastpage","2516"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","Kocun, Marta"],["dc.contributor.author","Mueller, Waltraut"],["dc.contributor.author","Maskos, Michael"],["dc.contributor.author","Mey, Ingo"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Steinem, Claudia"],["dc.contributor.author","Janshoff, Andreas"],["dc.date.accessioned","2017-09-07T11:46:43Z"],["dc.date.available","2017-09-07T11:46:43Z"],["dc.date.issued","2010"],["dc.description.abstract","We show how the viscoelastic properties of membranes formed from poly(butadiene)-block-poly(ethylene oxide) (PB(130)-b-PEO(66)) block copolymers can be locally accessed by atomic force microscopy. Polymer membranes are spread on microstructured porous silicon substrates from PB(130)-b-PEO(66) vesicles by decreasing the osmotic pressure of the solution. Local viscoelastic properties of the pore-spanning polymer membranes were obtained from site-specific indentation experiments. Elastic moduli of these membranes were in the order of few MPa, while the elastic moduli of crosslinked membranes considerably increased to few GPa. Furthermore, the energy dissipation and velocity dependence of the hysteresis between indentation and relaxation were quantified and compared with a modified Kelvin-Voigt model. Relaxation times were in the order of hundreds of milliseconds explaining why the stiffness of the membrane increases with increasing indentation velocity."],["dc.identifier.doi","10.1039/b924650a"],["dc.identifier.gro","3143006"],["dc.identifier.isi","000278046300021"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/473"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","1744-683X"],["dc.title","Viscoelasticity of pore-spanning polymer membranes derived from giant polymersomes"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4537"],["dc.bibliographiccitation.issue","16"],["dc.bibliographiccitation.journal","The Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces & Biophysical"],["dc.bibliographiccitation.lastpage","4545"],["dc.bibliographiccitation.volume","122"],["dc.contributor.author","Nöding, Helen"],["dc.contributor.author","Schön, Markus"],["dc.contributor.author","Reinermann, Corinna"],["dc.contributor.author","Dörrer, Nils"],["dc.contributor.author","Kürschner, Aileen"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Mey, Ingo"],["dc.contributor.author","Heussinger, Claus"],["dc.contributor.author","Janshoff, Andreas"],["dc.contributor.author","Steinem, Claudia"],["dc.date.accessioned","2020-12-10T15:22:43Z"],["dc.date.available","2020-12-10T15:22:43Z"],["dc.date.issued","2018"],["dc.identifier.doi","10.1021/acs.jpcb.7b11491"],["dc.identifier.eissn","1520-5207"],["dc.identifier.issn","1520-6106"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/73511"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Rheology of Membrane-Attached Minimal Actin Cortices"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2216"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Biophysical Journal"],["dc.bibliographiccitation.lastpage","2228"],["dc.bibliographiccitation.volume","110"],["dc.contributor.author","Savic, Filip"],["dc.contributor.author","Kliesch, Torben-Tobias"],["dc.contributor.author","Verbeek, Sarah"],["dc.contributor.author","Bao, Chunxiao"],["dc.contributor.author","Thiart, Jan"],["dc.contributor.author","Kros, Alexander"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Janshoff, Andreas"],["dc.date.accessioned","2018-11-07T10:14:08Z"],["dc.date.available","2018-11-07T10:14:08Z"],["dc.date.issued","2016"],["dc.description.abstract","The fusion of lipid membranes is a key process in biology. It enables cells and organelles to exchange molecules with their surroundings, which otherwise could not cross the membrane barrier. To study such complex processes we use simplified artificial model systems, i.e., an optical fusion assay based on membrane-coated glass spheres. We present a technique to analyze membrane-membrane interactions in a large ensemble of particles. Detailed information on the geometry of the fusion stalk of fully fused membranes is obtained by studying the diffusional lipid dynamics with fluorescence recovery after photo-bleaching experiments. A small contact zone is a strong obstruction for the particle exchange across the fusion spot. With the aid of computer simulations, fluorescence-recovery-after-photobleaching recovery times of both fused and single-membrane-coated beads allow us to estimate the size of the contact zones between two membrane-coated beads. Minimizing delamination and bending energy leads to minimal angles close to those geometrically allowed."],["dc.description.sponsorship","SFB [803 (B08)]"],["dc.identifier.doi","10.1016/j.bpj.2016.04.026"],["dc.identifier.isi","000376436700012"],["dc.identifier.pmid","27224487"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/40569"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Cell Press"],["dc.relation.issn","1542-0086"],["dc.relation.issn","0006-3495"],["dc.title","Geometry of the Contact Zone between Fused Membrane-Coated Beads Mimicking Cell-Cell Fusion"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","723"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Small"],["dc.bibliographiccitation.lastpage","726"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Schaefer, Edith"],["dc.contributor.author","Westendorf, Christian"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.contributor.author","Beta, Carsten"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Janshoff, Andreas"],["dc.date.accessioned","2018-11-07T08:58:03Z"],["dc.date.available","2018-11-07T08:58:03Z"],["dc.date.issued","2011"],["dc.identifier.doi","10.1002/smll.201001955"],["dc.identifier.isi","000288613000003"],["dc.identifier.pmid","21425455"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/23551"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1613-6810"],["dc.title","Shape Oscillations of Dictyostelium discoideum Cells on Ultramicroelectrodes Monitored by Impedance Analysis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","European Biophysics Journal"],["dc.bibliographiccitation.volume","44"],["dc.contributor.author","Vache, Marian"],["dc.contributor.author","Oelkers, Marieelen"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Janshoff, Andreas"],["dc.date.accessioned","2018-11-07T09:55:35Z"],["dc.date.available","2018-11-07T09:55:35Z"],["dc.date.issued","2015"],["dc.format.extent","S199"],["dc.identifier.isi","000380001400603"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/36780"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","New york"],["dc.relation.eventlocation","Dresden, GERMANY"],["dc.relation.issn","1432-1017"],["dc.relation.issn","0175-7571"],["dc.title","Cell mimetic adhesion by giant vesicles"],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e54172"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","PLoS One"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Schaefer, Edith"],["dc.contributor.author","Tarantola, Marco"],["dc.contributor.author","Polo, Elena"],["dc.contributor.author","Westendorf, Christian"],["dc.contributor.author","Oikawa, Noriko"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Janshoff, Andreas"],["dc.date.accessioned","2018-11-07T09:29:07Z"],["dc.date.available","2018-11-07T09:29:07Z"],["dc.date.issued","2013"],["dc.description.abstract","Chemotactic responses of Dictyostelium discoideum cells to periodic self-generated signals of extracellular cAMP comprise a large number of intricate morphological changes on different length scales. Here, we scrutinized chemotaxis of single Dictyostelium discoideum cells under conditions of starvation using a variety of optical, electrical and acoustic methods. Amebas were seeded on gold electrodes displaying impedance oscillations that were simultaneously analyzed by optical video microscopy to relate synchronous changes in cell density, morphology, and distance from the surface to the transient impedance signal. We found that starved amebas periodically reduce their overall distance from the surface producing a larger impedance and higher total fluorescence intensity in total internal reflection fluorescence microscopy. Therefore, we propose that the dominant sources of the observed impedance oscillations observed on electric cell-substrate impedance sensing electrodes are periodic changes of the overall cell-substrate distance of a cell. These synchronous changes of the cell-electrode distance were also observed in the oscillating signal of acoustic resonators covered with amebas. We also found that periodic cell-cell aggregation into transient clusters correlates with changes in the cell-substrate distance and might also contribute to the impedance signal. It turned out that cell-cell contacts as well as cell-substrate contacts form synchronously during chemotaxis of Dictyostelium discoideum cells."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2012"],["dc.description.sponsorship","DFG [SFB 937]"],["dc.identifier.doi","10.1371/journal.pone.0054172"],["dc.identifier.fs","599447"],["dc.identifier.isi","000313738900049"],["dc.identifier.pmid","23349816"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/8517"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30944"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Public Library Science"],["dc.relation.issn","1932-6203"],["dc.rights.access","openAccess"],["dc.title","Chemotaxis of Dictyostelium discoideum: Collective Oscillation of Cellular Contacts"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","12176"],["dc.bibliographiccitation.issue","33"],["dc.bibliographiccitation.journal","Journal of the American Chemical Society"],["dc.bibliographiccitation.lastpage","12179"],["dc.bibliographiccitation.volume","135"],["dc.contributor.author","Bao, Chunxiao"],["dc.contributor.author","Paehler, Gesa"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Janshoff, Andreas"],["dc.date.accessioned","2018-11-07T09:21:10Z"],["dc.date.available","2018-11-07T09:21:10Z"],["dc.date.issued","2013"],["dc.description.abstract","A major goal in neurophysiology and research on enveloped viruses is to understand and control the biology and physics of membrane fusion and its inhibition as a function of lipid and protein composition. This poses an experimental challenge in the realization of fast and reliable assays that allow us, with a minimal use of fluorescent or radioactive labels, to identify the different stages of membrane membrane interaction ranging from docking to complete membrane merging. Here, an optical two-dimensional fusion assay based on monodisperse membrane-coated microspheres is introduced, allowing unequivocal assignment of docking and membrane fusion. The hard-sphere fluid captures and quantifies relevant stages of membrane fusion and its inhibition without interference from aggregation, liposome rupture, extensive fluorescence labeling, and light scattering. The feasibility of the approach is demonstrated by using an established model system based on coiled-coil heterodimers formed between two opposing membrane-coated microspheres."],["dc.identifier.doi","10.1021/ja404071z"],["dc.identifier.isi","000323536100007"],["dc.identifier.pmid","23915348"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/29050"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","0002-7863"],["dc.title","Optical Fusion Assay Based on Membrane-Coated Spheres in a 2D Assembly"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","E6064"],["dc.bibliographiccitation.issue","30"],["dc.bibliographiccitation.journal","Proceedings of the National Academy of Sciences of the United States of America"],["dc.bibliographiccitation.lastpage","E6071"],["dc.bibliographiccitation.volume","114"],["dc.contributor.author","Schütte, Ole M."],["dc.contributor.author","Mey, Ingo"],["dc.contributor.author","Enderlein, Jörg"],["dc.contributor.author","Savić, Filip"],["dc.contributor.author","Geil, Burkhard"],["dc.contributor.author","Janshoff, Andreas"],["dc.contributor.author","Steinem, Claudia"],["dc.date.accessioned","2018-01-17T13:02:19Z"],["dc.date.available","2018-01-17T13:02:19Z"],["dc.date.issued","2017"],["dc.description.abstract","In the plasma membrane of eukaryotic cells, proteins and lipids are organized in clusters, the latter ones often called lipid domains or \"lipid rafts.\" Recent findings highlight the dynamic nature of such domains and the key role of membrane geometry and spatial boundaries. In this study, we used porous substrates with different pore radii to address precisely the extent of the geometric constraint, permitting us to modulate and investigate the size and mobility of lipid domains in phase-separated continuous pore-spanning membranes (PSMs). Fluorescence video microscopy revealed two types of liquid-ordered (lo) domains in the freestanding parts of the PSMs: (i) immobile domains that were attached to the pore rims and (ii) mobile, round-shaped lo domains within the center of the PSMs. Analysis of the diffusion of the mobile lo domains by video microscopy and particle tracking showed that the domains' mobility is slowed down by orders of magnitude compared with the unrestricted case. We attribute the reduced mobility to the geometric confinement of the PSM, because the drag force is increased substantially due to hydrodynamic effects generated by the presence of these boundaries. Our system can serve as an experimental test bed for diffusion of 2D objects in confined geometry. The impact of hydrodynamics on the mobility of enclosed lipid domains can have great implications for the formation and lateral transport of signaling platforms."],["dc.identifier.doi","10.1073/pnas.1704199114"],["dc.identifier.pmid","28696315"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/11700"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.eissn","1091-6490"],["dc.title","Size and mobility of lipid domains tuned by geometrical constraints"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]