IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Isolation of a photosynthetic bacterium from extreme environments in high-altitude andean wetlands
Autor/es:
DI CAPUA, CECILIA; FARIAS, MARIA EUGENIA; CORTEZ, NÉSTOR
Lugar:
Villa Carlos Paz, Argentina
Reunión:
Congreso; VI Cngreso Argentino de Microbiología General; 2009
Institución organizadora:
SAMIGE - Sociedad Argentina de Microbiología General
Resumen:
A photosynthetic bacterium was isolated from high-altitude wetlands (Laguna Azul) as purple colonies using rich media in anaerobiosis under light. After genomic DNA extraction, PCR amplification was performed using 16S 8-27 and 16S 1512-1491 primers. The single 1500bp product was sequenced and blasted against NCBI nucleotide database displaying 99% identity with Rhodopseudomonas palustris genome. We investigated the antioxidant response of the new isolated strain, in particular the detoxifying enzyme supeoxide dismutase (SOD). Crude extracts from both aerobic and photosynthetic cultures were subjected to non-denaturing gel electrophoresis and in situ SOD activity staining. A single SOD band was visualized, which displayed no inhibition by potassium cyanide or hydrogen peroxide indicating that Mn is the metal cofactor of the dismutase. Expression control by oxygen is deduced as a significant increase i SOD activity of cellular lysates was detected in cultures shifted from photosynthetic to respiratory conditions. Exponential cultures were plated onto rich and minimal agar-media and subjected to oxidative challenge using methylviologen or hydrogen peroxide. When compared to Rhodopseudomonas palustris 1e5 strain, no significant differences were found between antioxidant response of both strains.