IBIMOL   23987
INSTITUTO DE BIOQUIMICA Y MEDICINA MOLECULAR PROFESOR ALBERTO BOVERIS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Oxidative damage and reactive species generation in soybean cotyledons upon natural senescence
Autor/es:
ANDREA GALATRO,; MARCELA SIMONTACCHI; SEBASTIÁN JASID; JUAN J. VILLORDO; SUSANA PUNTARULO
Lugar:
Rosario, Santa Fe, Argentina
Reunión:
Congreso; XXXV Reunión Anual de la Sociedad Argentina de Biofísica; 2006
Institución organizadora:
Sociedad Argentina de Biofisica
Resumen:
The aim of this work was to evaluate the generation of nitric oxide (NO) and hydrogen peroxide (H2O2), during the senescence of soybean cotyledons (Glycine max var ADM 4800). Lipid radical content and electrolyte leakage were used as indexes of oxidative damage to membranes. Ion leakage was followed by changes in the conductivity of the water where cotyledons were placed. Ion leakage showed an exponential increase after 10 days and the pattern of cotyledons abscission from seedlings showed a drastic increase at day 15 after germination. Lipid radical content in soybean cotyledons, assessed by spin trapping EPR (electron paramagnetic resonance) [1], increased at day 12 after germination of the seeds. Nitric oxide (NO) content, evaluated by EPR [2] was detected at days 5-7 after germination, and non signal from the adduct NO-MGD-Fe was observed up to 22 days after germination. Nitrite-dependent NO generation was assessed by EPR, under conditions of maximal availability of substrate. The rate of NO generation was significantly higher at days 6 after germination as compared to the observed values over the tested period. H2O2 generation by intact cotyledons was assessed employing DCFH/HRP in the presence of DTPA to minimize metal catalysis [3]. A drastic increase in H2O2 generation on dry weight basis, was observed in cotyledons at 14-day after germination. Overall, the increase in ion leakage and lipid radical content as time progressed suggested that membrane integrity was altered. Oxidative modifications of membranes seem to be early events that precedes cotyledon falling. NO generated from nitrite-dependent pathways could be part of the complex mechanism that prevent early deterioration of cotyledons. On the other hand, H2O2 seems to be involved in the signaling pathways that triggers the starting of senescence and posterior falling of the cotyledons. [1] Jurkiewicz BA, Buettner GR Photochem Photobiol 1994, 59, 1-4. [2] Simontacchi M, Jasid S, Puntarulo S, Plant Sci, 2004, 167, 839-847. [3] Cathcart R, Schwiers E, Ames BN, Anal. Biochem, 1983, 134, 111–116. Supported by grants from CONICET, UBA and ANPCyTJurkiewicz BA, Buettner GR Photochem Photobiol 1994, 59, 1-4. [2] Simontacchi M, Jasid S, Puntarulo S, Plant Sci, 2004, 167, 839-847. [3] Cathcart R, Schwiers E, Ames BN, Anal. Biochem, 1983, 134, 111–116. Supported by grants from CONICET, UBA and ANPCyT