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BP: Fachverband Biologische Physik
BP 12: Poster II
BP 12.1: Poster
Dienstag, 2. April 2019, 14:00–16:00, Poster B2
High-statistics SAXS of desmin-expressing cells — •Chiara Cassini1, Manfred Burghammer2, Harald Herrman3, and Sarah Köster1 — 1IRP, Georg-August-Universität Göttingen, Germany — 2ESRF, Grenoble, France — 3DKFZ, Heidelberg, Germany
Desmin is the main intermediate filament (IF) protein in muscle cells. Recently, a large number of mutations in the desmin gene have been discovered to be pathogenic. In order to assess the structures formed in cells by normal and mutant desmin, a high resolution method, capable of retrieving structural information at sub-cellular length scales, without the need for slicing the cells, is preferable. Thus, we performed scanning small angle X-ray scattering (SAXS) experiments on three different cell lines generated from IF-free mouse fibroblasts: one expressing wild type desmin, one expressing R406W-desmin, and the IF-free mother cell clone itself. The cells were grown on Si3N4 windows and measured in freeze-dried state. Each window contained tens to hundreds of cells. In the past, each cell scan took minutes to hours. Recently, we were able to employ a special fast scanning mode that allowed us to image an entire window within a single scan in about 8 hours only. This approach ensured the collection of a statistically significant pool of data in a reasonable time span. However, the data analysis became more challenging: the selection of the different regions of interest needed to be automated. This was achieved by segmenting the dark field image of a scan with Bradley’s and Otsu’s thresholding; it was subsequently possible to compare local structure-related parameters of the three cell lines in a statistically relevant way.