title: Isolation of UVC-tolerant bacteria from the hyperarid Atacama Desert, Chile.
abstract: Martian surface microbial inhabitants would be challenged by a constant and unimpeded flux of UV radiation, and the study of analog model terrestrial environments may be of help to understand how such life forms could survive under this stressful condition. One of these environments is the Atacama Desert (Chile), a well-known Mars analog due to its extreme dryness and intense solar UV radiation. Here, we report the microbial diversity at five locations across this desert and the isolation of UVC-tolerant microbial strains found in these sites. Denaturing gradient gel electrophoresis (DGGE) of 16S rDNA sequences obtained from these sites showed banding patterns that suggest distinct and complex microbial communities. Analysis of 16S rDNA sequences obtained from UV-tolerant strains isolated from these sites revealed species related to the Bacillus and Pseudomonas genera. Vegetative cells of one of these isolates, Bacillus S3.300-2, showed the highest UV tolerance profile (LD(10) = 318 J m(2)), tenfold higher than a wild-type strain of Escherichia coli. Thus, our results show that the Atacama Desert harbors a noteworthy microbial community that may be considered for future astrobiological-related research in terms of UV tolerance.
authors.affiliation: Carlos Chagas Filho Biophysics Institute, Rio de Janeiro Federal University, Centro de Ciências da Saúde, Rio de Janeiro, RJ, Brazil. igplima@gmail.com
authors.forename: Ivan Gláucio
authors.initials: IG
authors.lastname: Paulino-Lima
authors.forename: Armando
authors.initials: A
authors.lastname: Azua-Bustos
authors.forename: Rafael
authors.initials: R
authors.lastname: Vicuña
authors.forename: Carlos
authors.initials: C
authors.lastname: González-Silva
authors.forename: Loreto
authors.initials: L
authors.lastname: Salas
authors.forename: Lia
authors.initials: L
authors.lastname: Teixeira
authors.forename: Alexandre
authors.initials: A
authors.lastname: Rosado
authors.forename: Alvaro Augusto da Costa
authors.initials: AA
authors.lastname: Leitao
authors.forename: Claudia
authors.initials: C
authors.lastname: Lage
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000528:radiation effects*; D044822:Biodiversity; D002677:Chile; D004269:DNA, Bacterial / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D003889:Desert Climate; D018559:Exobiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011836:Radiation Tolerance; D012988:Soil Microbiology; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S