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Laboratory simulation of interplanetary ultraviolet radiation (broad spectrum) and its effects on Deinococcus radiodurans |
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| Authors: | Ivan Gláucio Paulino-Lima Sérgio Pilling Eduardo Janot-Pacheco João Alexandre Ribeiro Gonçalves Barbosa Alvaro Costa Leitão |
| Institution: | a Instituto de Biofísica Carlos Chagas Filho, Avenida Carlos Chagas Filho, 373, Cidade Universitária, CEP 21941-902 Rio de Janeiro, RJ, Brazil b Laboratório Nacional de Luz Síncrotron, Rua Giuseppe Máximo Scolfaro, 10000, Pólo II de Alta Tecnologia de Campinas, CEP 13083-970 Campinas, SP, Brazil c Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Rua do Matão, 1226, Cidade Universitária, CEP 05508-900 São Paulo, SP, Brazil |
| Abstract: | The radiation-resistant bacterium Deinococcus radiodurans was exposed to a simulated interplanetary UV radiation at the Brazilian Synchrotron Light Laboratory (LNLS). Bacterial samples were irradiated on different substrates to investigate the influence of surface relief on cell survival. The effects of cell multi-layers were also investigated. The ratio of viable microorganisms remained virtually the same (average 2%) for integrated doses from 1.2 to 12 kJ m−2, corresponding to 16 h of irradiation at most. The asymptotic profiles of the curves, clearly connected to a shielding effect provided by multi-layering cells on a cavitary substrate (carbon tape), means that the inactivation rate may not change significantly along extended periods of exposure to radiation. Such high survival rates reinforce the possibility of an interplanetary transfer of viable microbes. |
| Keywords: | Panspermia Micro-shielding Vacuum ultraviolet Extremophile microorganisms |
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