Cyanobacteria use micro-optics to sense light direction
Nils Schuergers,
Tchern Lenn,
Ronald Kampmann,
Markus V Meissner,
Tiago Esteves,
Maja Temerinac-Ott,
Jan G Korvink,
Alan R Lowe,
Conrad W Mullineaux,
Annegret Wilde
Affiliations
Nils Schuergers
Institute of Biology III, University of Freiburg, Freiburg, Germany
Tchern Lenn
School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
Ronald Kampmann
Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Germany
Markus V Meissner
Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Germany
Tiago Esteves
Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; INEB- Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal; Faculdade de Engenharia da Universidade do Porto, Portugal
Maja Temerinac-Ott
Freiburg Institute for Advanced Studies, University of Freiburg, Freiburg, Germany
London Centre for Nanotechnology, London, United Kingdom; Institute for Structural and Molecular Biology, University College London and Birkbeck College London, London, United Kingdom
Conrad W Mullineaux
School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom; Freiburg Institute for Advanced Studies, University of Freiburg, Freiburg, Germany
Annegret Wilde
Institute of Biology III, University of Freiburg, Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
Bacterial phototaxis was first recognized over a century ago, but the method by which such small cells can sense the direction of illumination has remained puzzling. The unicellular cyanobacterium Synechocystis sp. PCC 6803 moves with Type IV pili and measures light intensity and color with a range of photoreceptors. Here, we show that individual Synechocystis cells do not respond to a spatiotemporal gradient in light intensity, but rather they directly and accurately sense the position of a light source. We show that directional light sensing is possible because Synechocystis cells act as spherical microlenses, allowing the cell to see a light source and move towards it. A high-resolution image of the light source is focused on the edge of the cell opposite to the source, triggering movement away from the focused spot. Spherical cyanobacteria are probably the world’s smallest and oldest example of a camera eye.
