TY - JOUR A1 - Zhukova, Yulia A1 - Hiepen, Christian A1 - Knaus, Petra A1 - Osterland, Marc A1 - Prohaska, Steffen A1 - Dunlop, John W. C. A1 - Fratzl, Peter A1 - Skorb, Ekaterina V. T1 - The role of titanium surface nanotopography on preosteoblast morphology, adhesion and migration JF - Advanced Healthcare Materials N2 - Surface structuring of titanium-based implants with appropriate nanotopographies can significantly modulate their impact on the biological behavior of cells populating these implants. Implant assisted bone tissue repair and regeneration require functional adhesion and expansion of bone progenitors. The surface nanotopography of implant materials used to support bone healing and its effect on cell behavior, in particular cell adhesion, spreading, expansion, and motility, is still not clearly understood. The aim of this study is to investigate preosteoblast proliferation, adhesion, morphology, and migration on different titanium materials with similar surface chemistry, but distinct nanotopographical features. Sonochemical treatment and anodic oxidation were employed to fabricate disordered – mesoporous titania (TMS), and ordered – titania nanotubular (TNT) topographies respectively. The morphological evaluation revealed a surface dependent shape, thickness, and spreading of cells owing to different adherence behavior. Cells were polygonal-shaped and well-spread on glass and TMS, but displayed an elongated fibroblast-like morphology on TNT surfaces. The cells on glass however, were much flatter than on nanostructured surfaces. Both nanostructured surfaces impaired cell adhesion, but TMS was more favorable for cell growth due to its support of cell attachment and spreading in contrast to TNT. Quantitative wound healing assay in combination with live-cell imaging revealed that cells seeded on TMS surfaces migrated in close proximity to neighboring cells and less directed when compared to the migratory behavior on other surfaces. The results indicate distinctly different cell adhesion and migration on ordered and disordered titania nanotopographies, providing important information that could be used in optimizing titanium-based scaffold design to foster bone tissue growth and repair. Y1 - 2017 U6 - https://doi.org/10.1002/adhm.201601244 ER - TY - CHAP A1 - Ritter, Zully A1 - Prohaska, Steffen A1 - Brand, R. A1 - Friedmann, A. A1 - Hege, Hans-Christian A1 - Goebbels, Jürgen A1 - Felsenberg, Dieter T1 - Osteocytes number and volume in osteoporotic and in healthy bone biopsies analysed using Synchrotron CT: a pilot study T2 - Proc. ISB 2011 Y1 - 2011 ER - TY - CHAP A1 - Streicher, Doreen A1 - Paetsch, Olaf A1 - Seiler, Robert A1 - Prohaska, Steffen A1 - Krause, Martin A1 - Boller, Christian T1 - 3-D-Visualisierung von Radar- und Ultraschallecho-Daten mit ZIBAmira T2 - Proc. DGZfP-Jahrestagung 2011 Y1 - 2011 ER - TY - CHAP A1 - Paetsch, Olaf A1 - Baum, Daniel A1 - Ehrig, Karsten A1 - Meinel, Dietmar A1 - Prohaska, Steffen T1 - Vergleich automatischer 3D-Risserkennungsmethoden für die quantitative Analyse der Schadensentwicklung in Betonproben mit Computer-Tomographie T2 - Tagungsband der DACH Jahrestagung 2012 Y1 - 2012 ER - TY - CHAP A1 - Paetsch, Olaf A1 - Baum, Daniel A1 - Breßler, David A1 - Ehrig, Karsten A1 - Meinel, Dietmar A1 - Prohaska, Steffen T1 - 3-D-Visualisierung und statistische Analyse von Rissen in mit Computer-Tomographie untersuchten Betonproben T2 - Tagungsband der DGZfP Jahrestagung 2013 Y1 - 2013 ER - TY - CHAP A1 - Paetsch, Olaf A1 - Baum, Daniel A1 - Ehrig, Karsten A1 - Meinel, Dietmar A1 - Prohaska, Steffen T1 - Automated 3D Crack Detection for Analyzing Damage Processes in Concrete with Computed Tomography T2 - Proceedings of Conference on Industrial Computed Tomography Y1 - 2012 SP - 321 EP - 330 ER - TY - GEN A1 - Costa, Marta A1 - Manton, James D. A1 - Ostrovsky, Aaron D. A1 - Prohaska, Steffen A1 - Jefferis, Gregory S.X.E. T1 - NBLAST: Rapid, sensitive comparison of neuronal structure and construction of neuron family databases N2 - Neural circuit mapping is generating datasets of 10,000s of labeled neurons. New computational tools are needed to search and organize these data. We present NBLAST, a sensitive and rapid algorithm, for measuring pairwise neuronal similarity. NBLAST considers both position and local geometry, decomposing neurons into short segments; matched segments are scored using a probabilistic scoring matrix defined by statistics of matches and non-matches. We validated NBLAST on a published dataset of 16,129 single Drosophila neurons. NBLAST can distinguish neuronal types down to the finest level (single identified neurons) without a priori information. Cluster analysis of extensively studied neuronal classes identified new types and unreported topographical features. Fully automated clustering organized the validation dataset into 1052 clusters, many of which map onto previously described neuronal types. NBLAST supports additional query types including searching neurons against transgene expression patterns. Finally we show that NBLAST is effective with data from other invertebrates and zebrafish. T3 - ZIB-Report - 16-34 KW - neuroinformatics KW - NBLAST KW - neuron similarity KW - cell type KW - clustering Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-59672 SN - 1438-0064 ER - TY - JOUR A1 - Costa, Marta A1 - Manton, James D. A1 - Ostrovsky, Aaron D. A1 - Prohaska, Steffen A1 - Jefferis, Gregory S.X.E. T1 - NBLAST: Rapid, Sensitive Comparison of Neuronal Structure and Construction of Neuron Family Databases JF - Neuron N2 - Neural circuit mapping is generating datasets of tens of thousands of labeled neurons. New computational tools are needed to search and organize these data. We present NBLAST, a sensitive and rapid algorithm, for measuring pairwise neuronal similarity. NBLAST considers both position and local geometry, decomposing neurons into short segments; matched segments are scored using a probabilistic scoring matrix defined by statistics of matches and non-matches. We validated NBLAST on a published dataset of 16,129 single Drosophila neurons. NBLAST can distinguish neuronal types down to the finest level (single identified neurons) without a priori information. Cluster analysis of extensively studied neuronal classes identified new types and unreported topographical features. Fully automated clustering organized the validation dataset into 1,052 clusters, many of which map onto previously described neuronal types. NBLAST supports additional query types, including searching neurons against transgene expression patterns. Finally, we show that NBLAST is effective with data from other invertebrates and zebrafish. Y1 - 2016 U6 - https://doi.org/10.1016/j.neuron.2016.06.012 VL - 91 IS - 2 SP - 293 EP - 311 ER - TY - GEN A1 - Redemann, Stefanie A1 - Lantzsch, Ina A1 - Lindow, Norbert A1 - Prohaska, Steffen A1 - Srayko, Martin A1 - Müller-Reichert, Thomas T1 - A switch in microtubule orientation during C. elegans meiosis N2 - In oocytes of many organisms, meiotic spindles form in the absence of centrosomes [1–5]. Such female meiotic spindles have a pointed appearance in metaphase with microtubules focused at acentrosomal spindle poles. At anaphase, the microtubules of acentrosomal spindles then transition to an inter- chromosomal array, while the spindle poles disappear. This transition is currently not understood. Previous studies have focused on this inter- chromosomal microtubule array and proposed a pushing model to drive chromosome segregation [6, 7]. This model includes an end-on orientation of microtubules with chromosomes. Alternatively, chromosomes were thought to associate along bundles of microtubules [8, 9]. Starting with metaphase, this second model proposed a pure lateral chromosome-to-microtubule association up to the final meiotic stages of anaphase. Here we applied large-scale electron tomography [10] of staged C. elegans oocytes in meiosis to analyze the orientation of microtubules in respect to chromosomes. We show that microtubules at metaphase I are primarily oriented laterally to the chromosomes and that microtubules switch to an end-on orientation during progression through anaphase. We further show that this switch in microtubule orientation involves a kinesin-13 microtubule depolymerase, KLP-7, which removes laterally associated microtubules around chromosomes. From this we conclude that both lateral and end-on modes of microtubule-to-chromosome orientations are successively used in C. elegans oocytes to segregate meiotic chromosomes. T3 - ZIB-Report - 18-34 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-69855 SN - 1438-0064 ER - TY - JOUR A1 - Redemann, Stefanie A1 - Lantzsch, Ina A1 - Lindow, Norbert A1 - Prohaska, Steffen A1 - Srayko, Martin A1 - Müller-Reichert, Thomas T1 - A switch in microtubule orientation during C. elegans meiosis JF - Current Biology N2 - In oocytes of many organisms, meiotic spindles form in the absence of centrosomes [1–5]. Such female meiotic spindles have a pointed appearance in metaphase with microtubules focused at acentrosomal spindle poles. At anaphase, the microtubules of acentrosomal spindles then transition to an inter- chromosomal array, while the spindle poles disappear. This transition is currently not understood. Previous studies have focused on this inter- chromosomal microtubule array and proposed a pushing model to drive chromosome segregation [6, 7]. This model includes an end-on orientation of microtubules with chromosomes. Alternatively, chromosomes were thought to associate along bundles of microtubules [8, 9]. Starting with metaphase, this second model proposed a pure lateral chromosome-to-microtubule association up to the final meiotic stages of anaphase. Here we applied large-scale electron tomography [10] of staged C. elegans oocytes in meiosis to analyze the orientation of microtubules in respect to chromosomes. We show that microtubules at metaphase I are primarily oriented laterally to the chromosomes and that microtubules switch to an end-on orientation during progression through anaphase. We further show that this switch in microtubule orientation involves a kinesin-13 microtubule depolymerase, KLP-7, which removes laterally associated microtubules around chromosomes. From this we conclude that both lateral and end-on modes of microtubule-to-chromosome orientations are successively used in C. elegans oocytes to segregate meiotic chromosomes. Y1 - 2018 U6 - https://doi.org/10.1016/j.cub.2018.07.012 SN - 0960-9822 ER - TY - CHAP A1 - Lindow, Norbert A1 - Redemann, Stefanie A1 - Brünig, Florian A1 - Fabig, Gunar A1 - Müller-Reichert, Thomas A1 - Prohaska, Steffen T1 - Quantification of three-dimensional spindle architecture T2 - Methods in Cell Biology Part B N2 - Mitotic and meiotic spindles are microtubule-based structures to faithfully segregate chromosomes. Electron tomography is currently the method of choice to analyze the three-dimensional (3D) architecture of both types of spindles. Over the years, we have developed methods and software for automatic segmentation and stitching of microtubules in serial sections for large-scale reconstructions. 3D reconstruction of microtubules, however, is only the first step toward biological insight. The second step is the analysis of the structural data to derive measurable spindle properties. Here, we present a comprehensive set of techniques to quantify spindle parameters. These techniques provide quantitative analyses of specific microtubule classes and are applicable to a variety of tomographic reconstructions of spindles from different organisms. Y1 - 2018 U6 - https://doi.org/10.1016/bs.mcb.2018.03.012 SN - 0091-679X VL - 145 SP - 45 EP - 64 PB - Academic Press ER -