ALBARRACIN Virginia Helena
congresos y reuniones científicas
UV-Resistant Extremophiles Isolated From Different Niches of High-Altitude Andean Lakes
FERRER M.G.; FARIAS M.E.; ALBARRACÍN V. H.
Congreso; 16th INTERNATIONAL CONGRESS ON PHOTOBIOLOGY; 2014
A wide variety of microorganisms inhabit extreme environments. High Altitude Andean Lakes (HAALs) over 3500 m asl presents one of the most extreme environments on Earth, exposed to extreme conditions such as high UV irradiation, hypersalinity, desiccation and high pH. Microorganisms that resist very severe physical and chemical conditions in their habitats are termed ?extremophiles?. The aim of this work is to isolate and characterize the microbial diversity present at the HAAL and to describe their multiple resistance properties towards the extreme factors that these microbial communities thrived in their natural environments. To find out the physiology of the isolates, polyextremophile assays were carried out with 54 strains. The drop method  was used for the screening of all parameters using LB agar media. Friedman statistical analysis determined that there were significative differences into UV-B tolerance (T2= 4,86; p< 0,001). With the multiple comparison test we observe that 36 strains out of 54 tested were significant resistant to UV-B. In this work, we report the first extensive isolation of HGC and LGC bacteria from soils, water, sediments and modern stromatolites at various locations within the Lakes. Considering the high elevation, geography, and physical?chemical characteristics of these wetlands, ultraviolet radiation is considered one of the most limiting abiotic factors for microbial communities in such ecosystems. We found strong UV-tolerance, added to resistance towards other extreme conditions (As, hypersalinity) in most strains. These results provide the basis for further research on the molecular strategies displayed by these isolates to endure the extreme environmental conditions of HAAL.  Di Capua, C., Bortolotti, A., Farías, M. E. Cortez, N. (2011). UV-resistant Acinetobacter sp. isolates from Andean wetlands display high catalase activity. FEMS Microbiol Lett 317, 181?189.