We present here selleck the first study on the UVB response and the antioxidant enzymatic defense of Acinetobacter HAAW

isolates Ver3, Ver5 and Ver7 from Lake Verde and N40 from Lake Negra. Bacterial strains Ver3, Ver5 and Ver7 were isolated from Andean Lake Verde and strain N40 from Lake Negra (Ordoñez et al., 2009). Both lakes are located at 4400 m above sea level in Catamarca, Argentina. All four strains belong to the Extremophile Strain Collection from the Laboratory of the Andean Lakes Microbiology Research (http://www.limla.com.ar). Three strains from the German Collection of Microorganisms and Cell Cultures (DSMZ) –A. baumannii DSM 30007, Acinetobacter johnsonii DSM 6963 and Acinetobacter lwoffii DSM 2403 – were included in the assays for comparison. Escherichia coli DH5α strain was used as a control for in situ SOD inhibition assay as described below. All cultures were grown in Luria–Bertani (LB) broth, supplemented with 2% agar for solid medium when applicable. The 16S rRNA gene sequences from 34 Acinetobacter strains used in this work were obtained from the National Center for Biotechnology Peptide 17 molecular weight Information (NCBI), (the corresponding accession numbers are: AM778686.1, AM410706.2, AM778688.1, AF509828.1, AM778690.1, X81663.1, AM778696.1, EU337121.1, AF509825.1, AJ293694.1, AF509826.1, AJ293693.1, GU388381.1, AJ626712.1, NR_028853.1, AJ303013.1, FJ907197.1, AJ295007.1,

EU661706.1, FJ608110.1, FJ860867.1, EF204273.1, GQ200824.1, DQ289068.1, FN563422.1, EF204280.1, FN563420.1, GU083586.1, X81660.1, FJ263924.1, AF509827.1, FN393792.1, NR_028851.1 and X81665.1.) The 16S rRNA gene sequences of the four isolates studied here were amplified previously using universal primers (F-27: AGAGTTTGATAMTGGCTCAG, R-1492: TACGGYTACCTTGTTACGACTT) and sequenced as described (Ordoñez et al., 2009). Nucleotide database searches were performed at NCBI using the blast network service. To construct the phylogenetic

trees, the sequences were aligned in the clustal x 2.0.9 program, which is a Windows interface for the clustal w multiple sequence alignment program (Larkin et al., 2007). treeview x version 0.5.0 was used to display phylogenies. All positions containing gaps and missing data were eliminated from the dataset manually. Analyses were performed by the neighbor-joining heptaminol (NJ) distance method within the same program (Saitou & Nei, 1987). Confidence limits to the inferences obtained by NJ were placed by the bootstrap procedure. Bacterial cultures collected at an OD600 nm of 0.4 were subjected to serial dilutions. Aliquots of 10 μL were then loaded onto LB agar plates, supplemented with methyl viologen (MV) (0.15 mM) or hydrogen peroxide (H2O2) (0.35 mM) when indicated. To evaluate tolerance to UV, plates were exposed to 9 × 103 J m−2 radiation using UVB lamps (maximum emission 302 nm, Bio-Rad Life Science) as light source.