Effect of UV radiation on bacterioplankton comunity of hypersaline Andean wetland (4,650 m)

MR FLORES; MARÍA V FERNANDEZ ZENOFF; OMAR F. ORDOÑEZ; MARÍA C. ESTEVEZ; MARÍA E. FARÍAS

Cairns, Australia

Simposio; 12th International Symposium on Microbial Ecology; 2008

ISME

Effect of UV radiation on bacterioplankton community of hypersaline Andean wetland (4,650 m) M.R. Flores, M.V. Fernandez-Zennof, O.F. Ordoñez, M.C. Estevez and M.E. Farias* * PROIMI. Av. Belgrano y Pasaje Caseros -(4000) - Tucumán, Argentina. Tel: 54-381-4344888 Fax -887  of  9:00 AM to 6:00 PM. E-mail: mefarias@proimi.org.ar, mefarias2001@yahoo.com.ar (preferid). The aim of this work was to study the effect of UV radiation (UVR) on bacterioplankton comunity from Laguna (L.) Vilama an hypersaline wetland (117 g/l) placed at 4,650 m altitude in the Argentinean northwest andean Puna desert. UVR expositions of wetland water were carried out in the laboratory during 24 hr. Samples were extracted at different times for determination of cultivable bacteria, determined by plating in two media with different salinities and identified by rDNA 16S gene partial sequence. Total community composition was studied by DGGE profiles with subsequent sequencing of the bands. In the same way, DNA damage was determinate messuring Cyclobutane Pyrimidine Dimers (CPDs) accumulation by western blotting. Among isolated strains under these experimental conditions, Stenotrophomonas maltophilia, Bacillus cereus, Bacillus sp., Bacterium sp, Vibrio costicola and Halobacillus profundi were the most resistant bacteria to UVR. Accumulation of CPDs in bacterioplankton, under artificial radiation, increased from 10 to 900 CPD MB-1 and reached more than 1200 CPD MB-1 in the beginning of exposition (control made calf thymus DNA). DGGE analisys showed the presence of bands that  presented high similitude with Gamma-proteobacteria (Halomonas sp., Idiomarinas sp., Marinobacter sp., and Pseudoalteromonas sp.), Alpha-proteobacteria (Roseobacter sp.), HGC (Agrococcus jenensis) and an unculturable Bacteroidetes specie. In the same way, bands intensity corresponding to Idiomonas marina, Marinobacter sp. and Pseudoalteromonas sp. increased during de radiation treatment. According to the found results, the high UVR resistance of L. Vilama bacterioplankton community was related mainly due to the presence of Gammaproteobacterias group.