Incidence of artificial UV-B radiation on bacterial community composition in two Andean wetlands

M. REGINA FLORES, OMAR FEDERICO ORDOÑEZ, M. CRISTINA ESTEVEZ, M.VERÓNICA FERNANDEZ-ZENNOF, M. EUGENIA FARIAS

Mar del Plata, Buenos Aires

Congreso; XLIII REUNIÓN ANUAL; 2007

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Laguna (L.) Negra and L. Verde are oligotrophic Andean wetlands, similar in altitude and environmental conditions, but different in salinity level. In this study we compared artificial UV-B radiation (UVR) incidence in bacterioplankton community of these two lakes. We have carried out expositions of both wetlands water to artificial UVR in the laboratory during 24 hrs. Samples were extracted at different times for determination of cultivable bacteria, determined by plating in two kinds of broth with different salinities and identified by rDNA 16S sequence. Total community composition was studied by DGGE profiles with subsequent sequencing of the bands. DNA damage was determinate with CPDs accumulation. We found 32 DGGE bands in L. Negra and 13 in L. Verde (13 and 2 corresponding to UVR resistance bacteria, respectively).  In these experimental conditions, 32 strains were isolated from L. Negra and 12 from L. Verde. DNA damage was increased in L. Negra total DNA and L.Verde total DNA from 0 to 1700 CPDs MB-1 and 1500 CPD MB-1, respectively. Bacteroidetes represented an important fraction of bacterial diversity and the community was enriches in this organisms by UVR stress in both lakes. These results could demonstrate that abundance of bacteroidetes in high irradiated environments in connection with its UV resistances than its ability to survive in halophile environments.