Sensitivity of Deinococcus radiodurans to gamma-irradiation: a novel approach by Fourier transform infrared spectroscopy.
Deinococcus radiodurans is a red-pigmented coccus known to be particularly resistant to both chemical and radiative agents. Fourier transform infrared (FT-IR) spectroscopy was used as a convenient and easy-to-run method to monitor damage induced in this bacterium by ionizing radiations. First, stationary-phase cultures were submitted to increasing doses of gamma-irradiation ((137)Cs source). Beyond a threshold of 11 kGy, striking changes occurred in spectra of irradiated samples compared with unirradiated ones, especially in the 1750-900 cm(-1) region, which is spectroscopically assigned to amide I and II components, nucleotide bases, the phosphodiester backbone, and the sugar ring. Second, bacterial cultures were postirradiation reincubated. After a reincubation time of 15 h, the oxidative stress was in part overwhelmed, and the growth of D. radiodurans again occurred, although some biocellular components remained altered. Consequently, FT-IR analysis is an accurate means to rapidly visualize biomolecular changes undergone by cells both after gamma-irradiation and during the repair mechanism.
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INSERM U443, Groupe de Chimie Bio-Organique, Université Victor Segalen Bordeaux 2, 146, rue Léo Saignat, Bordeaux Cedex, 33076, France. anne-marie.melin@bioorga.u-bordeaux2.fr
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D000465:Algorithms; D016000:Cluster Analysis; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D008837:Micrococcus / Q000254:growth & development / Q000528:radiation effects*; D018384:Oxidative Stress; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*