RESUMEN
The general goal of the experiment was to study the response of anhydrobiotic (metabolically dormant) microorganisms (spores of Bacillus subtilis, cells of Deinococcus radiodurans, conidia of Aspergillus species) and cellular constituents (plasmid DNA, proteins, purple membranes, amino acids, urea) to the extremely dehydrating conditions of open space, in some cases in combination with irradiation by solar UV-light. Methods of investigation included viability tests, analysis of DNA damages (strand breaks, DNA-protein cross-links) and analysis of chemical effects by spectroscopic, electrophoretic and chromatographic methods. The decrease in viability of the microorganisms was as expected from simulation experiments in the laboratory. Accordingly, it could be correlated with the increase in DNA damages. The purple membranes, amino acids and urea were not measurably effected by the dehydrating condition of open space (in the dark). Plasmid DNA, however, suffered a significant amount of strand breaks under these conditions. The response of these biomolecules to high fluences of short wavelength solar UV-light is very complex. Only a brief survey can be given in this paper. The data on the relatively good survival of some of the microorganisms call for strict observance of COSPAR Planetary Protection Regulations during interplanetary space missions.
Asunto(s)
Aspergillus/fisiología , Bacillus subtilis/fisiología , Cocos Grampositivos/fisiología , Vuelo Espacial , Rayos Ultravioleta , Ingravidez , Argón/farmacología , Aspergillus/efectos de los fármacos , Aspergillus/genética , Aspergillus/efectos de la radiación , Bacillus subtilis/efectos de los fármacos , Bacillus subtilis/genética , Bacillus subtilis/efectos de la radiación , Bacteriorodopsinas/efectos de los fármacos , Bacteriorodopsinas/efectos de la radiación , Recuento de Colonia Microbiana , Daño del ADN , ADN Bacteriano/efectos de los fármacos , ADN Bacteriano/genética , ADN Bacteriano/efectos de la radiación , ADN de Hongos/efectos de los fármacos , ADN de Hongos/genética , ADN de Hongos/efectos de la radiación , Desecación , Exobiología , Medio Ambiente Extraterrestre , Cocos Grampositivos/efectos de los fármacos , Cocos Grampositivos/genética , Cocos Grampositivos/efectos de la radiación , Plásmidos/efectos de los fármacos , Plásmidos/genética , Plásmidos/efectos de la radiación , Esporas Bacterianas , VacioRESUMEN
The inactivation of the anhydrobiotic organisms Bacillus subtilis (spores) and Deinococcus radiodurans during long-term exposure (up to several weeks) to extreme dryness (especially vacuum) is correlated with an increase in the number of DNA-strand breaks and other DNA lesions. Survival finally depends on the repair of DNA damages. Exposure of anhydrobiotic organisms to extreme dryness (e.g. on Mars or in space) for geological times will lead to so extended DNA lesions that recovery is extremely unlikely.