Optical properties of microbial cells ans sensing the light direction in phototaxis
Plant Biochemistry and Biophysics
Plant Physiology
Cell Biology
Final Report Abstract
Cyanobacteria are capable of phototaxis, the ability to move towards or away from a light source. Understanding the mechanisms behind cyanobacterial movement has implications for our understanding of their ecological roles in their natural habitats. In this project, two groups with expertise in optics and microbiology aimed to analyze the physical and biochemical principles of directional light sensing. The refractive index of cyanobacterial cells was found to be non-uniform, with higher values in the thylakoid membrane layers compared to the cytoplasm. These micro-optical properties of cyanobacterial cells allow the cell body to act as an optical lens and define the direction of the incoming light. To analyze bacterial movements, both groups worked together to evaluate optimal surfaces for the analysis of bacterial movements and to fabricate a portable manipulation platform for the positioning of small dielectric objects, such as microbes, in a light beam. The Wilde group further focused on understanding the dynamics of cellular appendages, the Type IV pili, which are used by bacteria for movement on surfaces. The successful fluorescent labeling of the pilus filament now allows us to observe dynamics of pili in live cells. We also identified components of the signal transduction chain involved in pilus assembly, including chemotaxis-like response regulators harboring a specific hitherto not studied domain that interacts with the pilus motor and the platform. We found that this domain alone is able to bind to Type IV pili and that phosphorylation of specific regulators modulates this binding. This project has provided insights into the mechanisms underlying cyanobacterial phototaxis and the dynamics of type IV pili assembly in response to light signals. The development of new nano-optical methods to analyze bacterial cells and the use of innovative techniques, such as electro-optic biochips, for studying single-cell movement in response to light signals will be significant advancements in the field of bacterial research.
Publications
-
Fototaxis – Wie Cyanobakterien zum Licht finden. In: Unterricht Biologie, 448. Friedrich Verlag GmbH, ISSN 0341-5260
Wilde A.
-
The (PATAN)-CheY-Like Response Regulator PixE Interacts with the Motor ATPase PilB1 to Control Negative Phototaxis in the Cyanobacterium Synechocystis sp. PCC 6803. Plant and Cell Physiology, 61(2), 296-307.
Jakob, Annik; Nakamura, Hiroshi; Kobayashi, Atsuko; Sugimoto, Yuki; Wilde, Annegret & Masuda, Shinji
-
The Role of the Cyanobacterial Type IV Pilus Machinery in Finding and Maintaining a Favourable Environment. Life, 10(11), 252.
Conradi, Fabian D.; Mullineaux, Conrad W. & Wilde, Annegret
-
The social life of cyanobacteria. eLife, 10.
Mullineaux, Conrad W. & Wilde, Annegret
-
PATAN‐domain regulators interact with the Type IV pilus motor to control phototactic orientation in the cyanobacterium Synechocystis. Molecular Microbiology, 117(4), 790-801.
Han, Yu; Jakob, Annik; Engel, Sophia; Wilde, Annegret & Schuergers, Nils
-
Thermosynechococcus switches the direction of phototaxis by a c-di-GMP-dependent process with high spatial resolution. eLife, 11.
Nakane, Daisuke; Enomoto, Gen; Bähre, Heike; Hirose, Yuu; Wilde, Annegret & Nishizaka, Takayuki
-
Dynamic dielectrophoretic cell manipulation is enabled by an innovative electronics platform. Biosensors and Bioelectronics: X, 14, 100333.
Julius, Lourdes Albina Nirupa; Scheidt, Henrik; Krishnan, Gowri; Becker, Moritz; Nassar, Omar; Torres-Delgado, Sarai M.; Mager, Dario; Badilita, Vlad & Korvink, Jan G.
-
Surface characterisation reveals substrate suitability for cyanobacterial phototaxis. Acta Biomaterialia, 155, 386-399.
Julius, Lourdes Albina Nirupa; Matter, Lukas; Schuergers, Nils; Lützenkirchen, Johannes; Trouillet, Vanessa; Gil-Díaz, Teba; Mamleyev, Emil R.; Wilde, Annegret; Badilita, Vlad & Korvink, Jan G.
