Secondary metabolism responses in two Pisum sativum L. cultivars cultivated under Fe deficiency conditions

The present study was carried out to investigate the Fe deficiency effect on the secondary metabolism  responses in two Pisum sativum cultivars characterized by different tolerance to Fe deficiency. Previous study  investigating the physiological responses to Fe deficiency in these two pea cultivars showed that Kelvedon was  more tolerant than Lincoln. Both cultivars were grown in the absence or presence of Fe with the addition of bicarbonate for twelve days. Higher concentrations of phenols and flavonoids were observed in Fe-deficient  tissues of both cultivars; however, the increase was greater in the tolerant cultivar than in the susceptible  one. The activity of shikimate pathway enzymes tested was more enhanced in the tolerant cultivar. In  addition, lipid peroxidation and H2O2 concentrations were more increased in the susceptible cultivar when  compared with the tolerant one. Peroxidase activity was increased in the tolerant cultivar grown under  bicarbonate supply, while a considerable diminution was observed in the susceptible one, suggesting the  involvement of this antioxidant enzyme in the tolerance of pea to Fe deficiency. The lignifying peroxidases  activity was more decreased in Lincoln than in Kelvedon, especially in the presence of bicarbonate. Our data  suggest that the tolerance of Kelvedon was related to its ability to modulate the phenolic metabolism pathway and to enhance the antioxidant potentials.Key words: Iron deficiency, bicarbonate, phenolic metabolism, antioxidative enzymes, Pisum sativum

The Influence of the Calcination Time on Synthesis of Nanomaterials with Small Size, High Crystalline Nature and Photocatalytic Activity in the TiO2 Nanoparticles Calcined at 500 °C

The development of new materials with diverse applications that fit well in the context of the current economy, where energy issues abound, is paramount. The goal of this study was to generate materials with high photocatalytic properties, at low cost and with less energy, and without health and ecological risks. Such materials would allow for a form of sustainable development that respects nature. This study investigated the influence of calcination time on titanium dioxide nanoparticles (TiO2 NPs) produced by green synthesis using Aloe vera leaf extract under a constant temperature of 500 °C. The interaction between synthesis conditions like calcination time and the size of nanoparticles produced in relation to changes in photocatalytic activity were analyzed and discussed. The results showed that when calcination was increased at 500 °C, the synthesis of small-diameter nanoparticles was promoted. TiO2 were 23 ± 2 nm (D1) and 83 ± 5 nm (D2) after 5 h and 1 h of calcination, respectively. Moreover, the calcination duration promoted an increase in crystalline nature. In the same way, the level of reduction of azo dye Remazol Red Brilliant F3B (RR180) increased when calcination time increased, and therefore, changed the optic and photo-catalytic properties of the TiO2 nanomaterial. In addition, TiO2 nanopowders (size 23 ± 2 nm) had the higher efficiency in photodegradation (100%) of dye RR180 under visible light irradiation for 60 min for up to one hour duration, but TiO2 NPs (83 ± 5 nm) had the higher efficiency (100%) for up to two hours duration

The Influence of the Calcination Time on Synthesis of Nanomaterials with Small Size, High Crystalline Nature and Photocatalytic Activity in the TiO₂ Nanoparticles Calcined at 500 °C

The development of new materials with diverse applications that fit well in the context of the current economy, where energy issues abound, is paramount. The goal of this study was to generate materials with high photocatalytic properties, at low cost and with less energy, and without health and ecological risks. Such materials would allow for a form of sustainable development that respects nature. This study investigated the influence of calcination time on titanium dioxide nanoparticles (TiO2 NPs) produced by green synthesis using Aloe vera leaf extract under a constant temperature of 500 °C. The interaction between synthesis conditions like calcination time and the size of nanoparticles produced in relation to changes in photocatalytic activity were analyzed and discussed. The results showed that when calcination was increased at 500 °C, the synthesis of small-diameter nanoparticles was promoted. TiO2 were 23 ± 2 nm (D1) and 83 ± 5 nm (D2) after 5 h and 1 h of calcination, respectively. Moreover, the calcination duration promoted an increase in crystalline nature. In the same way, the level of reduction of azo dye Remazol Red Brilliant F3B (RR180) increased when calcination time increased, and therefore, changed the optic and photo-catalytic properties of the TiO2 nanomaterial. In addition, TiO2 nanopowders (size 23 ± 2 nm) had the higher efficiency in photodegradation (100%) of dye RR180 under visible light irradiation for 60 min for up to one hour duration, but TiO2 NPs (83 ± 5 nm) had the higher efficiency (100%) for up to two hours duration

[Retracted] Effect of cadmium on resumption of respiration in cotyledons of germinating pea seeds

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Former Editor-in-Chief and co-authors. The article includes content plagiarised from articles that have already appeared in the following journals. See: https://doi.org/10.1016/j.ecoenv.2010.05.015International audiencePea seeds (Pisum sativum L.) were germinated by soaking in H2O OR 5mM CdCl2 during a 5-day period. Enzyme activities involved in respiratory metabolism were studied in cotyledons. Mitochondrial cytochrome c oxidase and NADH- and succinate-cytochrome c reductase activities wer inhibited by cadmium treatment. The effects of Cd were performed in vivo and in vitro allowing to distinguish between the direct inhibition of the enzyme activities and the influence of the same enzymes into the cell environment. However, Cd exposure stimulated an enzyme activity of fermentation and inhibited the capacity of the enzyme inactivator (alcool dehydogenase inactivator). Moreover, the enzyme activities of NAD(P)H-recycling dehydogenases via secondary pentose phosphate pahtway, glucose-6-phosphate- and 6-phosphogluconate-dehydrogenases, were enhanced in Cd-stressed seeds. The findings will help clarify the overall mechanisms that underlie cadmium-mediated toxicity in germinating seeds

Cadmium Affects the Glutathione/Glutaredoxin System in Germinating Pea Seeds

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceThe aim of this work was to investigate the effects of cadmium (Cd) on thiol and especially glutathione (GSH)-dependent reactions (glutathione content, glutaredoxin (Grx) content and activity, "glutathione" peroxidase (Gpx) activity, and glutathione reductase (GR) activity) in germinating pea seeds. Under Cd stress conditions, the overall activity as well as more specifically the expression of Grx C4 and Grx S12 increased. On the contrary, when incubated with Cd ions in vitro, the disulfide reductase activity of both isoforms was drastically inhibited. In the case of Grx C4, this correlated with the formation of protein dimers of 28 kDa as evidenced by electrophoresis analysis. Oxidative stress also affected the GSH status, since Cd treatment provoked (1) a pronounced stimulation in Gpx (a thioredoxin-dependent enzyme in plants) expression and (2) a drastic decrease in GR activity. These results are discussed in relation with the known contribution of Grx system to the thiol status during the germination of Cd-poisoned pea seeds

[Retracted] Redox regulation of the glutathione reductase/iso-glutaredoxin system in germinating pea seed exposed to cadmium

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The editors would like to confirm the retraction of this paper at the request of the co-authors who had no prior knowledge on the actions of the lead author. See: https://doi.org/10.1016/j.plantsci.2010.06.015International audienceThe present work aims at understanding the regulation of the glutathione/glutathione reductase/glutaredoxin system (GSH/GR/GRX) in plant, namely the transition from heterotrophic growth to photoautotrophic metabolism in seedlings. Pea seeds were analyzed between 0 and 5 days. This study compares seedlings grown in the presence or absence of external cadmium. GSH/GR/GRX system was studied separately in cotyledons that mainly serve to reserve breakdown and in embryonic axes that prepare for cell elongation and cell division associated with radicle emergence. We made extracts of the proteins at various stages of the development, quantify their protein content and use them for activity measurements and estimation of specific protein levels. Cadmium caused a reduction of the total glutathione content. The levels of glutaredoxin C4 (GRX C4) and glutaredoxin 512 (GRX S12) showed a Cd-dependent increase, although GRX activity was depressed. Glutathione reductase activity was significantly reduced by cadmium. However, Cd treatment provoked a strong induction in protein level and activity of glutathione peroxidase (GPX). The disturbances in the resumption of redox metabolism may be a contributory cause of deleterious effect of cadmium on pea seed germination. (C) 2010 Elsevier Ireland Ltd. All rights reserved