Düsseldorf 2007 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 73: Laserspektroskopie II

Q 73.7: Vortrag

Freitag, 23. März 2007, 15:30–15:45, 5K

Investigation of fast changes of the excitation energy transfer efficiency in the cyanobacterium Acaryochloris marina by time- and wavelength resolved fluorescence spectroscopy — •Franz-Josef Schmitt¹, Karin Wache¹, Justus Fuesers¹, Hann-Jörg Eckert², and Hans Joachim Eichler¹ — ¹Institut für Optik und Atomare Physik, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin — ²Max-Volmer-Laboratorium, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin

The interaction of the photosynthetic subunits and especially the mechanisms regulating the energy transfer are presently interesting and open fields in photosynthesis research. In this study we use time- and wavelength-correlated single photon counting to investigate the fluorescence dynamics in living cells of A.marina simultaneously in the visible and near infrared spectrum. Very short measurement times, low excitation light intensities and a high signal to noise ratio are attributes necessary to investigate photosynthetic processes in sensitive biological samples, when the light emission varies due to metabolic changes. Exposing of living cells of A.marina to low temperature (0°C) was found to cause a decoupling of the membrane extrinsic phycobiliprotein antenna from Photosystem II, which is partially reversible when the sample is kept at 25 °C for a short time. This reversible decoupling of the phycobiliprotein antenna could be a protection mechanism against photo damage of the reaction center of Photosystem II during cold stress .