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Lichen Vitality After a Space Flight on Board the EXPOSE-R2 Facility Outside the International Space Station: Results of the Biology and Mars Experiment
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Orientador(es)
Resumo(s)
As part of the Biology and Mars Experiment (BIOMEX; ILSRA 2009-0834), samples of the lichen Circinaria
gyrosa were placed on the exposure platform EXPOSE-R2, on the International Space Station (ISS) and
exposed to space and to a Mars-simulated environment for 18 months (2014–2016) to study: (1) resistance to
space and Mars-like conditions and (2) biomarkers for use in future space missions (Exo-Mars). When the
experiment returned (June 2016), initial analysis showed rapid recovery of photosystem II activity in the
samples exposed exclusively to space vacuum and a Mars-like atmosphere. Significantly reduced recovery
levels were observed in Sun-exposed samples, and electron and fluorescence microscopy (transmission electron microscope and field emission scanning electron microscope) data indicated that this was attributable to the combined effects of space radiation and space vacuum, as unirradiated samples exhibited less marked morphological changes compared with Sun-exposed samples. Polymerase chain reaction analyses confirmed that there was DNA damage in lichen exposed to harsh space and Mars-like environmental conditions, with
ultraviolet radiation combined with space vacuum causing the most damage. These findings contribute to the
characterization of space- and Mars-resistant organisms that are relevant to Mars habitability.
Descrição
Palavras-chave
EXPOSE R2 ISS Space Mars-simulated Environment DNA Integrity Morphological Changes Lichen
Contexto Educativo
Citação
Astrobiology. 2020 May;20(5):583-600. doi: 10.1089/ast.2018.1959
Editora
Mary Ann Liebert/ Astrobiology Society