title: Molecular investigation of the radiation resistance of edible cyanobacterium Arthrospira sp. PCC 8005.
abstract: The aim of this work was to characterize in detail the response of Arthrospira to ionizing radiation, to better understand its radiation resistance capacity. Live cells of Arthrospira sp. PCC 8005 were irradiated with60Co gamma rays. This study is the first, showing that Arthrospira is highly tolerant to gamma rays, and can survive at least 6400 Gy (dose rate of 527 Gy h-1), which identified Arthrospira sp. PCC 8005 as a radiation resistant bacterium. Biochemical, including proteomic and transcriptomic, analysis after irradiation with 3200 or 5000 Gy showed a decline in photosystem II quantum yield, reduced carbon fixation, and reduced pigment, lipid, and secondary metabolite synthesis. Transcription of photo-sensing and signaling pathways, and thiol-based antioxidant systems was induced. Transcriptomics did show significant activation of ssDNA repair systems and mobile genetic elements (MGEs) at the RNA level. Surprisingly, the cells did not induce the classical antioxidant or DNA repair systems, such superoxide dismutase (SOD) enzyme and the RecA protein. Arthrospira cells lack the catalase gene and the LexA repressor. Irradiated Arthrospira cells did induce strongly a group of conserved proteins, of which the function in radiation resistance remains to be elucidated, but which are a promising novel routes to be explored. This study revealed the radiation resistance of Arthrospira, and the molecular systems involved, paving the way for its further and better exploitation.
authors: Expert Group for Molecular and Cellular Biology, Belgian Nuclear Research Center SCK•CEN, Mol, Belgium.|Proteomics and Microbiology Group, Research Institute for Biosciences, University of Mons, Mons, Belgium.
authors: Hanène
authors: H
authors: Badri
authors: Expert Group for Molecular and Cellular Biology, Belgian Nuclear Research Center SCK•CEN, Mol, Belgium.
authors: Pieter
authors: P
authors: Monsieurs
authors: Expert Group for Molecular and Cellular Biology, Belgian Nuclear Research Center SCK•CEN, Mol, Belgium.
authors: Ilse
authors: I
authors: Coninx
authors: Proteomics and Microbiology Group, Research Institute for Biosciences, University of Mons, Mons, Belgium.
authors: Ruddy
authors: R
authors: Wattiez
authors: Expert Group for Molecular and Cellular Biology, Belgian Nuclear Research Center SCK•CEN, Mol, Belgium.
authors: Natalie
authors: N
authors: Leys
keywords: 
  Arthrospira
  ; cyanobacteria; ionizing radiation; microarray; proteomics