Following DNA Compaction During the Cell Cycle by X-ray Nanodiffraction

Hémonnot, Clément Y. J.; Ranke, Christiane; Saldanha, Oliva; Graceffa, Rita; Hagemann, J.; Köster, Sarah

doi:10.1021/acsnano.6b05034

Cited by 10 publications

(17 citation statements)

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“…[28][29][30] Electromagnetic waves (e. g. visible-light, X-ray) microscopies can allow fast full-field imaging. Electron microscopies and nano X-ray techniques 31,32 provide the highest resolution in situ imaging of nanoparticle electrochemistry, although their radiations can induce chemical side effects. 33 Several groups, including ours, are suggesting that super-localization optical microscopies [34][35][36][37][38][39][40][41] are easier to implement to image electrochemical processes at individual nanoobjects in the 20-100 nm range, in two or three dimensions, with high temporal resolution and negligible material damage.…”

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confidence: 99%

Monitoring Cobalt-Oxide Single Particle Electrochemistry with Subdiffraction Accuracy

et al. 2018

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By partially overcoming the diffraction limit, superlocalization techniques have extended the applicability of optical techniques down to the nanometer size-range. Herein, cobalt oxide-based nanoparticles are electrochemically grown onto carbon nanoelectrodes and their individual catalytic properties are evaluated through a combined electrochemical-optical approach. Using dark-field white light illumination, edges superlocalization techniques are applied to quantify changes in particle size during electrochemical activation with down to 20 nm precision. It allows the monitoring of (i) the anodic electrodeposition of cobalt hydroxide material and (ii) the large and reversible volume expansion experienced by the cobalt hydroxide particle during its oxidation. Meanwhile, the particle light scattering provides chemical information such as the Co redox state transformation, which complements both the particle size and the recorded electrochemical current and provides in operando mechanistic information on particle electrocatalytic properties.

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confidence: 99%

Monitoring Cobalt-Oxide Single Particle Electrochemistry with Subdiffraction Accuracy

et al. 2018

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“…Thus, moderate resolution in real space is ISSN 1600-5775 complemented by high resolution in reciprocal space. Thanks to this unique combination, several subcellular structures were studied in whole cells, including keratin bundles in SK8/18-2 cells (Weinhausen et al, 2012(Weinhausen et al, , 2014Hé monnot et al, 2016a), actin bundles in hair cell stereocilia (Piazza et al, 2014) and in Dictyostelium discoideum (Priebe et al, 2014) and chromatin in 3T3 fibroblasts (Hé monnot et al, 2016b). A model-free diffraction pattern analysis was demonstrated for several cell types (Bernhardt et al, 2016).…”

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confidence: 99%

Large field-of-view scanning small-angle X-ray scattering of mammalian cells

Cassini¹,

Wittmeier²,

Brehm³

et al. 2020

J Synchrotron Rad

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X-ray imaging is a complementary method to electron and fluorescence microscopy for studying biological cells. In particular, scanning small-angle X-ray scattering provides overview images of whole cells in real space as well as local, high-resolution reciprocal space information, rendering it suitable to investigate subcellular nanostructures in unsliced cells. One persisting challenge in cell studies is achieving high throughput in reasonable times. To this end, a fast scanning mode is used to image hundreds of cells in a single scan. A way of dealing with the vast amount of data thus collected is suggested, including a segmentation procedure and three complementary kinds of analysis, i.e. characterization of the cell population as a whole, of single cells and of different parts of the same cell. The results show that short exposure times, which enable faster scans and reduce radiation damage, still yield information in agreement with longer exposure times.

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“…In order to interpret the scattering patterns correctly, we have therefore simulated the situation [6,7] in order to fit the two-dimensional patterns or the azimuthally integrated I(q) curves (see figure 1d). For the keratin bundles we were thus able to derive values for filament diameter, bundles diameter, filament distance and "lattice type" -very much in agreement with EM data, albeit without the need of slicing the cell sample.We also applied scanning SAXS to the nucleus in eukaryotic cells (see figure 2 a,c), with special attention to changes during the cell division cycles [8]. In this case, as the DNA strands are tightly packed rather…”

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confidence: 99%

“…We also applied scanning SAXS to the nucleus in eukaryotic cells (see figure 2 a,c), with special attention to changes during the cell division cycles [8]. In this case, as the DNA strands are tightly packed rather…”

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Scanning Small-Angle-X-Ray Scattering for Imaging Biological Cells

et al. 2018

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Scanning small angle X-ray scattering (SAXS) bridges two worlds of X-ray imaging: We use highly focused beams to spatially resolve the different constituents inside biological cells. Additionally, each individual scattering pattern contains a wealth of information about the internal structure on molecular length scales. X-rays provide high resolution due to their small wave length and high penetration power, allowing for imaging of large three-dimensional objects. For these reasons, X-rays have been established as complementary probes for bio-imaging, besides well-established methods like visible light fluorescence microscopy and electron microscopy (EM). Scanning SAXS, in particular, is well suited for systems with some degree of order, such as bundles of parallel filaments, or high-density aggregates [1].Here, we present scanning SAXS experiments that were performed at dedicated synchrotron beamlines providing a small beam between 100 nm and 2 µm diameter, high flux, high-end pixel detectors and a sample environment suitable for cell samples, e.g. ID13 at the European Synchrotron Radiation Facility (ESRF), P10 at Deutsches Elektronen-Synchrotron (DESY) or cSAXS at Swiss Light Source (SLS). We use X-ray energies between 7 and 15 keV. A schematic of a typical setup is shown in figure 1a. In the following, we will summarize the most important results we recently obtained on different biological systems, such as components of the cytoskeleton and the DNA in the nucleus.The cytoskeleton of eukaryotic cells is a "composite" biopolymer network consisting mainly of three filament types, actin filaments, microtubules and intermediate filaments, along with a large number of cross linkers and molecular motors. These filaments possess differing mechanical properties, in terms of bending and stretching resistance and form complex structures like bundles and networks. It is well accepted that these networks are to a great part responsible for the mechanical properties of the cell and it is likely that these properties are encoded in the specific architecture of filaments and their superstructures. Thus, we have imaged keratin networks in epithelial cells (see figure 1b) [2-4] and actin parallel bundles in stereocilial hair cells from mouse inner ears (see figure 1c) [5] by this technique. Typically, we compute dark field images, where we integrate the total scattered intensity in each scattering pattern and plot the resulting value on a color scale as a "pixel" in the respective position, for real space overview images. If the individual scattering patterns are plotted in a composite image, they reveal the degree and the direction of the orientation of subcellular structures, which is then further quantified. An important point is that in this case the size of the scatterer (filament bundle with a diameter on the order of 100 nm) and the beam size are very similar. In order to interpret the scattering patterns correctly, we have therefore simulated the situation [6,7] in order to fit the two-dimensional patterns or the azim...

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Following DNA Compaction During the Cell Cycle by X-ray Nanodiffraction

Cited by 10 publications

References 71 publications

Monitoring Cobalt-Oxide Single Particle Electrochemistry with Subdiffraction Accuracy

Monitoring Cobalt-Oxide Single Particle Electrochemistry with Subdiffraction Accuracy

Large field-of-view scanning small-angle X-ray scattering of mammalian cells

Scanning Small-Angle-X-Ray Scattering for Imaging Biological Cells

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