Dresden 2017 – scientific programme

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BP: Fachverband Biologische Physik

BP 27: Posters - Microswimmers

BP 27.4: Poster

Tuesday, March 21, 2017, 14:00–16:00, P2-EG

Light-activated flagella dynamics of Chlamydomonas in contact with a surface — •Christine Linne, Christian Kreis, and Oliver Bäumchen — Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, D-37077 Göttingen, Germany

The photoactive microalga Chlamydomonas reinhardtii typically lives in complex environments such as soil and has two modes of locomotion: freely swimming in liquid and gliding on a surface. By performing in vivo force spectroscopy experiments we discovered that light stimulation regulates the transition between both motility modes, since the adhesiveness of the flagella can be reversibly switched on and off by light [1]. We held a Chlamydomonas cell with a micropipette force sensor in close proximity to a substrate, such that the flagella tips can physically sense the surface during every beating cycle. After light stimulation, the flagella provide adhesive contacts with the surface and actively pull the cell body towards the substrate. Time-resolved in vivo micropipette experiments reveal the forces exerted by the cell during this process. We explain the flagella dynamics using a model which takes into account the activity of the molecular motors within the flagella. [1] C. Kreis, M. Le Blay, C. Linne, M. Makowski, and O. Bäumchen, in review (2016).