title: Exposure of phage T7 to simulated space environment: the effect of vacuum and UV-C radiation.
abstract: The experiment "Phage and Uracil Response" (PUR) will be accommodated in the EXPOSE facility of the International Space Station (ISS). Its objective is to examine and quantify the effect of specific space conditions on bacteriophage T7 and isolated T7 DNA thin films. In order to define the environmental and technical requirements of the EXPOSE, the samples were subjected to the Experiment Verification Test (EVT). During EVT the samples were exposed to selected space conditions: high vacuum (10(-4) to 10(-6) Pa) and UV-C radiation (254 nm) alone and in combination. Characteristic changes in the absorption spectrum, in the electrophoretic pattern of DNA/phage and the decrease of the amount of PCR products have been detected indicating the damage of isolated and intraphage T7 DNA. Intraphage DNA is more sensitive to simulated space parameters than isolated T7 DNA in thin layers as well. We obtained substantial evidence that DNA lesions accumulate throughout exposure, and the amount of damage depends on the thickness of the layers. According to our preliminary results, the damages by exposure to conditions of dehydration and UV irradiation are larger than the sum of vacuum alone, or radiation alone case, suggesting a synergistic action of space vacuum and UV radiation with DNA being the critical target.
authors.affiliation: Institute of Biophysics and Radiation Biology, Semmelweis University, Puskin u. 9, H-1088 Budapest, Hungary.
authors.forename: Márton
authors.initials: M
authors.lastname: Hegedüs
authors.forename: Gáspár
authors.initials: G
authors.lastname: Kovács
authors.forename: Károly
authors.initials: K
authors.lastname: Módos
authors.forename: Györgyi
authors.initials: G
authors.lastname: Rontó
authors.forename: Helmut
authors.initials: H
authors.lastname: Lammer
authors.forename: Corinna
authors.initials: C
authors.lastname: Panitz
authors.forename: Andrea
authors.initials: A
authors.lastname: Fekete
mesh_terms: D017123:Bacteriophage T7 / Q000235:genetics* / Q000528:radiation effects*; D004249:DNA Damage / Q000528:radiation effects; D004279:DNA, Viral / Q000528:radiation effects*; D005118:Extraterrestrial Environment; D014466:Ultraviolet Rays; D014618:Vacuum
chemical_list: D004279:DNA, Viral