Presence of mucB exceptionally UV-B Resistance strains isolated from pristine Argentinean Andean wetlands

ORDONEZ O; FERNANDEZ ZENOFF MV; MARTÍNEZ MA; DIB JR; FARIAS ME

Vienna, Austria

Simposio; 11th International Symposium on Microbial Ecology; 2006

International Society for Microbial Ecology

Introduction In Argentinean Andes, at high altitude inaccessible oligotrophic wetlands were isolated Gram positive bacteria (Bacillus, Actynomices and Staphylococcus genera) and Gram negative ones ( Pseudomonas and Acinetobacter genera). Since these extreme environments are exposed to high UV radiation, presence of mutagenesis SOS related genes, and if are if they were somehow transmissible by conjugation to a sensible Bacillus subtilis rifampicin resitant strain were tested. Methods Lake water plus agar and Luria Bertani medium were used to isolate bacterial cultivable community. Total DNA was obtained using CTAB followed by chloroform extractions and plasmids using alkaline lisis method. Presence of mucB (mutagenesis enhancement, GenBank U72482) genes was performed using primers towards pKM101 and its product labeled for hybridizations using aliquots of total DNA of the samples, as well as PCR reactions. Assays were done on both, native strains and Bacillus subtilis transconjugants, which were obtained at frequencies of 10-6 to 10-9. Results Six native strains showed signals using mucB as a probe, using pKM101 as a control with hybridization stringent conditions. However, PCR reactions gave similar bands to that of the control in not all positive strains. Sequences of the bands obtained are pendent. Transconjugants were analyzed to verify if those genes were plasmid encoded, since UV-B irradiation of them showed remarkable increased of resistance. Conclusions Since the exposure of these uplands to high UV-B irradiation have selected strains from different species with exceptionally UV-B resistance, our results suggest that this resistance may be encoded into transferable elements.