Figure 1

Schematic representation of the experimental ptychography setup for imaging living cells. (a) For the X-ray ptychography experiments, a monochromatic (λ = 0.2 nm) beam was used to coherently illuminate a pinhole. The cell sample was scanned to collect a series of diffraction patterns from partially overlapping illuminated regions, which allow for a robust image reconstruction. The high dynamic range and count rate of the detector allows us to record the full dynamic range of the 2D diffraction patterns at the detector and avoid a loss of low spatial-frequency information that would occur if a beamstop was used. (b) A visible light bright-field optical micrograph shows three fission Schizosaccharomyces pombe yeast cells under nitrogen starvation conditions, where two of them were banana-shaped zygotes. (c) Corresponding fluorescence microscopy images of the same cells as in (b) in a time interval of 5 min are shown. In order to distinguish zygotes with moving chromosomes, ‘nuclear oscillations’, among cells with ‘non-oscillating’ ones, the rec25 gene was labeled with green fluorescent protein (GFP) and used as an indirect marker of DNA double strand breaks²⁴. Here, only one of two zygotes was at the horsetail stage.