Dresden 2009 – scientific programme

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BP: Fachverband Biologische Physik

BP 17: Poster II

BP 17.35: Poster

Wednesday, March 25, 2009, 17:15–19:45, P3

4D-Tracking of pathogens by digital in-line holography — •Sebastian Weiße¹, Matthias Heydt¹, Niko Heddergott², Markus Engstler², Michael Grunze¹, and Axel Rosenhahn¹ — ¹Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany — ²Institut für Mikrobiologie und Genetik, Technische Universität Darmstadt, Schnittspahnstraße 10, 64287 Darmstadt, Germany

Digital in-line holography is based on the original idea of D. Gabor’s ‘new microscopic principle’. An interference pattern of the so-called ‘source wave’ and the so-called ‘object wave’ is recorded. It contains three dimensional information of the object encoded in phase and amplitude. From a time series of such holograms, three dimensional trajectories of moving microorganisms can be retrieved.

We have built a portable, temperature-controllable digital in-line holographic microscope to study the motion patterns of the blood parasite Trypanosoma brucei, the causative agent of African sleeping sickness under physiological conditions. Its cork-screw-like self-propulsion in the bloodstream of a mammalian host is essential for the clearing of immunglobulins from the cell surface by hydrodynamic drag force. Motility is therefore pivotal to evade the host’s immune system. So far, the locomotion of the parasite has only been studied in 2D. Using our system parasites were tracked at varying temperatures and viscosities with high spatial and temporal accuracy in 3D. The ability to track different cell strains under varying physical conditions will lead to a deeper understanding of their locomotion and thus their pathogenesis.