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DNA repair - Watching the cell work

Microbeam of PTB irradiates living cells with single particles- repair process is made visible by fluorescence


 The effect of high doses of ionizing radiation - as it is released in the case of nuclear accidents or the use of nuclear weapons - is indisputable and has been widely documented. The effects of low radiation doses on human cells have not yet, however, been sufficiently investigated. Here, scientists of the Physikalisch-Technische Bundesanstalt (PTB) want to gain new knowledge, in cooperation with molecular biologists: with the aid of a micro ion beam, called "microbeam", they irradiate the components of living cells selectively with single or counted particles. On the double-strand breaks of the DNA caused by it, repair mechanisms are initiated within seconds or minutes which can be made visible by a fluorescence process. This now allows the repair process to be observed "live", i.e. in real time, under the microscope. This procedure, which is called "Live Cell Imaging", is to provide information about both radiation damage and the sequence of different repair mechanisms in the cells and to show to what extent drugs can affect these processes.

Am Microbeam wurden menschliche Zellen (hier: Fibroblasten) in einem Muster (Linienabstand 10 µm, Trefferabstand ca.1 µm, symbolisiert durch die gelben Punkte) mit α-Teilchen bestrahlt. Entlang der Teilchenbahn entstehen Doppelstrangbrüche in der DNA. Auf dem Bild leuchten sie, weil sich fluoreszenzmarkierte Reparaturproteine an den Bruchstellen sammeln.

Dr. Ulrich Giesen, Working Group 6.41, Micro ion beam and ion dosimetry,
phone: +49 (0) 531 592-6410,
e-mail: ulrich.giesen(at)ptb.de