Study of the effect of simulated space environment on phage T7 and isolated T7 DNA thin films

Phage and uracil response (PUR) experiment is part of the ROSE consortium selected by the European Space Agency for the first mission on the EXPOSE facility of the International Space Station. Its main goal is to examine and quantify the effect of specific space conditions (e.g. solar UV radiation, vacuum) on nucleic acid models. To achieve this, an improved method was elaborated for the preparation of DNA and bacteriophage thin films. The homogeneity of the films was controlled by UV spectroscopy and microscopy. To provide experimental evidence for the hypothesis that interplanetary transfer of life is possible, phage T7 and isolated T7 DNA thin films have been exposed to selected space conditions: intense UVC radiation (λ=254 nm) and high vacuum (10−5 mbar). The effects of DNA hydration, conformation and packing on UV radiation damage were examined. Characteristic changes in the absorption spectrum, in the electrophoretic pattern of DNA and the decrease of the amount of PCR products have been detected indicating the photodamage of isolated and intraphage DNA. The paper summarizes the spectroscopical data.