title: Transcriptome analysis applied to survival of Shewanella oneidensis MR-1 exposed to ionizing radiation.
abstract: The ionizing radiation (IR) dose that yields 20% survival (D20) of Shewanella oneidensis MR-1 is lower by factors of 20 and 200 than those for Escherichia coli and Deinococcus radiodurans, respectively. Transcriptome analysis was used to identify the genes of MR-1 responding to 40 Gy (D20). We observed the induction of 170 genes and repression of 87 genes in MR-1 during a 1-h recovery period after irradiation. The genomic response of MR-1 to IR is very similar to its response to UV radiation (254 nm), which included induction of systems involved in DNA repair and prophage synthesis and the absence of differential regulation of tricarboxylic acid cycle activity, which occurs in IR-irradiated D. radiodurans. Furthermore, strong induction of genes encoding antioxidant enzymes in MR-1 was observed. DNA damage may not be the principal cause of high sensitivity to IR, considering that MR-1 carries genes encoding a complex set of DNA repair systems and 40 Gy IR induces less than one double-strand break in its genome. Instead, a combination of oxidative stress, protein damage, and prophage-mediated cell lysis during irradiation and recovery might underlie this organism's great sensitivity to IR.
authors.affiliation: Center for Microbial Ecology, PSSB 540, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Qiu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Daly
authors.forename: Alexander
authors.initials: A
authors.lastname: Vasilenko
authors.forename: Marina V
authors.initials: MV
authors.lastname: Omelchenko
authors.forename: Elena K
authors.initials: EK
authors.lastname: Gaidamakova
authors.forename: Liyou
authors.initials: L
authors.lastname: Wu
authors.forename: Jizhong
authors.initials: J
authors.lastname: Zhou
authors.forename: George W
authors.initials: GW
authors.lastname: Sundin
authors.forename: James M
authors.initials: JM
authors.lastname: Tiedje
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics; D004249:DNA Damage / Q000528:radiation effects*; D004260:DNA Repair / Q000528:radiation effects; D045643:DNA Repair Enzymes / Q000235:genetics* / Q000528:radiation effects; D015964:Gene Expression Regulation, Bacterial / Q000528:radiation effects*; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D039002:Prophages / Q000235:genetics; D011836:Radiation Tolerance; D011839:Radiation, Ionizing; D017382:Reactive Oxygen Species / Q000378:metabolism; D020592:Shewanella / Q000235:genetics / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D017382:Reactive Oxygen Species; D045643:DNA Repair Enzymes