Dresden 2014 – scientific programme
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BP: Fachverband Biologische Physik
BP 34: Imaging
BP 34.2: Talk
Thursday, April 3, 2014, 09:45–10:00, ZEU 250
3D-Density Measurements of the Bacterium Deinococcus Radiodurans by Tomo-Ptychographic X-ray Imaging — •Robin N. Wilke1, Marius Priebe1, Matthias Bartels1, Klaus Giewekemeyer2, Ana Diaz3, Malte Vassholz1, and Tim Salditt1 — 1Institut für Röntgenphysik, Universität Göttingen, Germany — 2European XFEL, Hamurg, Germany — 3Paul Scherrer Institut, Villigen, Switzerland
D.radiodurans[1,2] is famous for its extraordinary resistance to high doses of ionizing radiation, which has been tentatively linked to the structural organization of DNA in the nucleoid[3,4]. Determination of the mesoscopic density in the nucleoid would help to test these ideas and eventually to discriminate different models of DNA packing.
Ptychographic phasing[5-9] is one promising (coherent) X-ray imaging technique for this particular problem and other biological applications. We present results of quantitative 3D resolved mass density maps of D.radiodurans by a combination of ptychography and tomography of unstained, unsliced and freeze-dried bacterial cells[8]. In addition, we show how ptychographic results can be enhanced by increasing the dynamic range of pixel detectors by introducing a Semi-Transparent Central Stop[9].
[1]Levin-Zaidman et al.,Science299,2003
[2]Eltsov&Dubochet,J.Bacteriol.187,2005
[3]Eltsov&Dubochet,J.Bacteriol.188,2006
[4]Minsky et al.,J.Bacteriol.188, 2006
[5]Rodenburg et al.,PRL98,2007.
[6]Thibault et al.,Science321,2008
[7]Giewekemeyer et al.,PNAS107,2010
[8]Wilke et al.,Opt.Expr.20,2012
[9]Wilke et. al.,ActaCryst.A69,2013