Anisotropic x-ray scattering and orientation fields in cardiac tissue cells. (12th January 2017)
- Record Type:
- Journal Article
- Title:
- Anisotropic x-ray scattering and orientation fields in cardiac tissue cells. (12th January 2017)
- Main Title:
- Anisotropic x-ray scattering and orientation fields in cardiac tissue cells
- Authors:
- Bernhardt, M
Nicolas, J-D
Eckermann, M
Eltzner, B
Rehfeldt, F
Salditt, T - Abstract:
- Abstract: X-ray diffraction from biomolecular assemblies is a powerful technique which can provide structural information about complex architectures such as the locomotor systems underlying muscle contraction. However, in its conventional form, macromolecular diffraction averages over large ensembles. Progress in x-ray optics has now enabled to probe structures on sub-cellular scales, with the beam confined to a distinct organelle. Here, we use scanning small angle x-ray scattering (scanning SAXS) to probe the diffraction from cytoskeleton networks in cardiac tissue cells. In particular, we focus on actin-myosin composites, which we identify as the dominating contribution to the anisotropic diffraction patterns, by correlation with optical fluorescence microscopy. To this end, we use a principal component analysis approach to quantify direction, degree of orientation, nematic order, and the second moment of the scattering distribution in each scan point. We compare the fiber orientation from micrographs of fluorescently labeled actin fibers to the structure orientation of the x-ray dataset and thus correlate signals of two different measurements: the native electron density distribution of the local probing area versus specifically labeled constituents of the sample. Further, we develop a robust and automated fitting approach based on a power law expansion, in order to describe the local structure factor in each scan point over a broad range of the momentum transfer q r .Abstract: X-ray diffraction from biomolecular assemblies is a powerful technique which can provide structural information about complex architectures such as the locomotor systems underlying muscle contraction. However, in its conventional form, macromolecular diffraction averages over large ensembles. Progress in x-ray optics has now enabled to probe structures on sub-cellular scales, with the beam confined to a distinct organelle. Here, we use scanning small angle x-ray scattering (scanning SAXS) to probe the diffraction from cytoskeleton networks in cardiac tissue cells. In particular, we focus on actin-myosin composites, which we identify as the dominating contribution to the anisotropic diffraction patterns, by correlation with optical fluorescence microscopy. To this end, we use a principal component analysis approach to quantify direction, degree of orientation, nematic order, and the second moment of the scattering distribution in each scan point. We compare the fiber orientation from micrographs of fluorescently labeled actin fibers to the structure orientation of the x-ray dataset and thus correlate signals of two different measurements: the native electron density distribution of the local probing area versus specifically labeled constituents of the sample. Further, we develop a robust and automated fitting approach based on a power law expansion, in order to describe the local structure factor in each scan point over a broad range of the momentum transfer q r . Finally, we demonstrate how the methodology shown for freeze dried cells in the first part of the paper can be translated to alive cell recordings. … (more)
- Is Part Of:
- New journal of physics. Volume 19:Number 1(2017:Jan.)
- Journal:
- New journal of physics
- Issue:
- Volume 19:Number 1(2017:Jan.)
- Issue Display:
- Volume 19, Issue 1 (2017)
- Year:
- 2017
- Volume:
- 19
- Issue:
- 1
- Issue Sort Value:
- 2017-0019-0001-0000
- Page Start:
- Page End:
- Publication Date:
- 2017-01-12
- Subjects:
- protein fibers -- actin -- cardiomyocytes -- small-angle x-ray scattering -- x-ray focussing -- nano-diffraction
Physics -- Periodicals
Physics
Periodicals
530.05 - Journal URLs:
- http://iopscience.iop.org/1367-2630 ↗
http://njp.org/index.html ↗
http://ioppublishing.org/ ↗ - DOI:
- 10.1088/1367-2630/19/1/013012 ↗
- Languages:
- English
- ISSNs:
- 1367-2630
- Deposit Type:
- Legaldeposit
- View Content:
- Available online (eLD content is only available in our Reading Rooms) ↗
- Physical Locations:
- British Library DSC - BLDSS-3PM
British Library HMNTS - ELD Digital store - Ingest File:
- 11091.xml