IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Comparative Survival Analysis ofDeinococcus radioduransand the HaloarchaeaNatrialba magadiiandHaloferax volcanii Exposed to Vacuum Ultraviolet Irradiation
Autor/es:
ABREVAYA, X. C.; PAULINO-LIMA, I. G.; GALANTE, D.; RODRIGUES, F.; MAUAS, P.J.D.; CORTÓN, E.; LAGE, C.
Revista:
ASTROBIOLOGY
Editorial:
MARY ANN LIEBERT INC
Referencias:
Lugar: New York; Año: 2011 vol. 11 p. 1034 - 1040
ISSN:
1531-1074
Resumen:
The haloarchaea Natrialba magadii and Haloferax volcanii, as well as the radiation-resistant bacterium Deinococcus radiodurans, were exposed to vacuum-UV (V-UV) radiation at the Brazilian Synchrotron Light Laboratory (LNLS). Cell monolayers (containing 105 - 106 cells per sample) were prepared over polycarbonate filters and irradiated under high vacuum (10-5 Pa) with polychromatic synchrotron radiation. N. magadii was remarkably resistant to high vacuum with a survival fraction of ((3.77 pm 0.76) x 10-2), larger than the one of D. radiodurans ((1.13 pm 0.23) x 10-2). The survival fraction of the haloarchaea H. volcanii, of ((3.60 pm 1.80) x 10-4), was much smaller. Radiation resistance profiles were similar between the haloarchaea and D. radiodurans for fluencies up to 150 J m-2. For fluencies larger than 150 J m-2 there was a significant decrease in the survival of haloarchaea, and in particular H. volcanii did not survive. Survival for D. radiodurans was 1% after exposure to the higher V-UV fluency (1350 J m-2) while N. magadii had a survival lower than 0.1%. Such survival fractions are discussed regarding the possibility of interplanetary transfer of viable micro-organisms and the possible existence of microbial life in extraterrestrial salty environments such as the planet Mars and the Jupiter´s moon Europa. This is the first work reporting survival of haloarchaea under simulated interplanetary conditions.