Plants are exposed to environmental stress,in natural and agricultural conditions.Nitric oxide(NO),a small gaseous molecule which plays important roles in plants,has been involved in many physiological processes,and e...Plants are exposed to environmental stress,in natural and agricultural conditions.Nitric oxide(NO),a small gaseous molecule which plays important roles in plants,has been involved in many physiological processes,and emerged as an important endogenous signaling molecule in the adaptation of plants to biotic and abiotic stress.NO is produced from a variety of enzymatic and non enzymatic sources,which are not yet fully understood.Also,NO and reactive nitrogen species(RNS)can produce posttranslational modifications affecting protein function.Nitrate reductase,a key enzyme in the nitrogen metabolism,is a proposed source of NO in plants which could be affected by posttranslational modifications.Thus,different pathways seem to be involved and can also regulate NO synthesis in the plant cell under physiological or stress conditions.However,how the levels of NO are reached in such time and place to fulfill its functions,are still puzzles to elucidate.展开更多
The main aim of this work was to assess the multi-task role of ferritin （Ft） in the oxidative metabolism of soybean （Glycine max）. Soybean seeds incubated for 24 h yielded 41 4- 5μg Ft/g fresh weight. The rate of...The main aim of this work was to assess the multi-task role of ferritin （Ft） in the oxidative metabolism of soybean （Glycine max）. Soybean seeds incubated for 24 h yielded 41 4- 5μg Ft/g fresh weight. The rate of in vitro incorporation of iron （Fe） into Ft was tested by supplementing the reaction medium with physiological Fe chelators. The control rate, observed in the presence of 100μM Fe, was not significantly different from the values observed in the presence of 100 μM Fe-his. However, it was significantly higher in the presence of 100 μM Fe-citrate （approximately 4.5-fold） or of 100 μM Fe-ATP （approximately 14-fold）. Moreover, a substantial decrease in the Trp-dependent fluorescence of the Ft protein was determined during Fe uptake from Fe-citrate, as compared with the control. On the other hand, Ft addition to homogenates from soybean embryonic axes reduced endogenously generated ascorbyl radical, according to its capacity for Fe uptake. The data presented here suggest that Ft could be involved in the generation of free radicals, such as hydroxyl radical, by Fe-catalyzed reactions. Moreover, the scavenging of these radicals by Ft itself could then lead to protein damage. However, Ft could also prevent cellular damage by the uptake of catalytically active Fe.展开更多
文摘Plants are exposed to environmental stress,in natural and agricultural conditions.Nitric oxide(NO),a small gaseous molecule which plays important roles in plants,has been involved in many physiological processes,and emerged as an important endogenous signaling molecule in the adaptation of plants to biotic and abiotic stress.NO is produced from a variety of enzymatic and non enzymatic sources,which are not yet fully understood.Also,NO and reactive nitrogen species(RNS)can produce posttranslational modifications affecting protein function.Nitrate reductase,a key enzyme in the nitrogen metabolism,is a proposed source of NO in plants which could be affected by posttranslational modifications.Thus,different pathways seem to be involved and can also regulate NO synthesis in the plant cell under physiological or stress conditions.However,how the levels of NO are reached in such time and place to fulfill its functions,are still puzzles to elucidate.
基金supported by grants from the University of Buenos Aires
文摘The main aim of this work was to assess the multi-task role of ferritin （Ft） in the oxidative metabolism of soybean （Glycine max）. Soybean seeds incubated for 24 h yielded 41 4- 5μg Ft/g fresh weight. The rate of in vitro incorporation of iron （Fe） into Ft was tested by supplementing the reaction medium with physiological Fe chelators. The control rate, observed in the presence of 100μM Fe, was not significantly different from the values observed in the presence of 100 μM Fe-his. However, it was significantly higher in the presence of 100 μM Fe-citrate （approximately 4.5-fold） or of 100 μM Fe-ATP （approximately 14-fold）. Moreover, a substantial decrease in the Trp-dependent fluorescence of the Ft protein was determined during Fe uptake from Fe-citrate, as compared with the control. On the other hand, Ft addition to homogenates from soybean embryonic axes reduced endogenously generated ascorbyl radical, according to its capacity for Fe uptake. The data presented here suggest that Ft could be involved in the generation of free radicals, such as hydroxyl radical, by Fe-catalyzed reactions. Moreover, the scavenging of these radicals by Ft itself could then lead to protein damage. However, Ft could also prevent cellular damage by the uptake of catalytically active Fe.
