Luisa María Sandalio González - Academia.edu (original) (raw)

Papers by Luisa María Sandalio González

Research paper thumbnail of Peroxisomal Metabolism and Dynamics at the Crossroads Between Stimulus Perception and Fast Cell Responses to the Environment

Frontiers in Cell and Developmental Biology, 2020

Research paper thumbnail of Percoll reversibly inhibits superoxide dismutase

Revista española de fisiología, 1985

Incubation of pea leaf extracts (Pisum sativum L.) at 6 degrees C in isoosmotic media containing ... more Incubation of pea leaf extracts (Pisum sativum L.) at 6 degrees C in isoosmotic media containing different Percoll concentrations significantly represses the total superoxide dismutase (SOD) activity in a concentration- and time-dependent manner. After 24 h incubation at 6 degrees C, 30-45% Percoll concentrations bring about an inhibition of Mn-SOD activity of more than 50%. Isozyme Cu,Zn-SOD II is affected to a lesser extent, with a maximum inhibition of 36% at high Percoll concentrations, whereas isozyme Cu,Zn-SOD I undergoes only slight variations. However, dilution of the samples followed by electrophoresis completely removes the Percoll inhibitory action. Results suggest that superoxide dismutases could be adsorbed onto the Percoll surface through electrostatic interactions.

Research paper thumbnail of Peroxisomes, Reactive Oxygen Metabolism, and Stress-Related Enzyme Activities

Plant Peroxisomes, 2002

... On the contrary, peroxisomal manganese superoxide dismutase (EC 1.15. ... In these two cellul... more ... On the contrary, peroxisomal manganese superoxide dismutase (EC 1.15. ... In these two cellular organelles the production of superoxide radicals, and the induction of SOD isozymes in ... Conversely, the activity of glycolate oxidase was stimulated by NaCl in salt-tolerant plants. ...

Research paper thumbnail of Localization of Superoxide Dismutase in Glyoxysomes from Citrullus vulgaris. Functional Implications in Cellular Metabolism

Journal of Plant Physiology, 1987

ABSTRACT

Research paper thumbnail of Plant Peroxisomes, Reactive Oxygen Metabolism and Nitric Oxide

IUBMB Life, 2008

In plant cells, as in most eukaryotic organisms, peroxisomes are probably the major sites of intr... more In plant cells, as in most eukaryotic organisms, peroxisomes are probably the major sites of intracellular H2O2 production, as a result of their essentially oxidative type of metabolism. Like mitochondria and chloroplasts, peroxisomes also produce superoxide radicals (O2*-) and there are, at least, two sites of superoxide generation: one in the organelle matrix, the generating system being xanthine oxidase, and another site in the peroxisomal membranes dependent on NAD(P)H. In peroxisomal membranes, three integral polypeptides (PMPs) with molecular masses of 18, 29, and 32 kDa have been shown to generate O2*- radicals. Besides catalase, several antioxidative systems have been demonstrated in plant peroxisomes, including different superoxide dismutases, the four enzymes of the ascorbate-glutathione cycle plus ascorbate and glutathione, and three NADP-dependent dehydrogenases. A CuZn-SOD and two Mn-SODs have been purified and characterized from different types of plant peroxisomes. The presence of the enzyme nitric oxide synthase (NOS) and its reaction product, nitric oxide (NO*), has been recently demonstrated in plant peroxisomes. Different experimental evidence has suggested that peroxisomes have a ROS-mediated cellular function in leaf senescence and in stress situations induced by xenobiotics and heavy metals. Peroxisomes could also have a role in plant cells as a source of signal molecules like NO*, O2*- radicals, H2O2, and possibly S-nitrosoglutathione (GSNO). It seems reasonable to think that a signal molecule-producing function similar to that postulated for plant peroxisomes could also be performed by human, animal and yeast peroxisomes, where research on oxy radicals, antioxidants and nitric oxide is less advanced than in plant peroxisomes.

Research paper thumbnail of Nutritional Effect and Expression of SODs: Induction and Gene Expression; Diagnostics; Prospective Protection Against Oxygen Toxicity

Free Radical Research Communications, 1991

Research paper thumbnail of Nitric Oxide and Globin Glb1 Regulate Fusarium oxysporum Infection of Arabidopsis thaliana

Antioxidants

Plants continuously interact with fungi, some of which, such as Fusarium oxysporum, are lethal, l... more Plants continuously interact with fungi, some of which, such as Fusarium oxysporum, are lethal, leading to reduced crop yields. Recently, nitric oxide (NO) has been found to play a regulatory role in plant responses to F. oxysporum, although the underlying mechanisms involved are poorly understood. In this study, we show that Arabidopsis mutants with altered levels of phytoglobin 1 (Glb1) have a higher survival rate than wild type (WT) after infection with F. oxysporum, although all the genotypes analyzed exhibited a similar fungal burden. None of the defense responses that were analyzed in Glb1 lines, such as phenols, iron metabolism, peroxidase activity, or reactive oxygen species (ROS) production, appear to explain their higher survival rates. However, the early induction of the PR genes may be one of the reasons for the observed survival rate of Glb1 lines infected with F. oxysporum. Furthermore, while PR1 expression was induced in Glb1 lines very early on the response to F. oxy...

Research paper thumbnail of Screening Arabidopsis mutants in genes useful for phytoremediation

Journal of Hazardous Materials, 2017

<xps:span class="xps_Image">fx1 Highlights► A screening of 7,... more <xps:span class="xps_Image">fx1 Highlights► A screening of 7,000 mutants in a medium containing three heavy metals was done ► Protein metabolism and signalling mutants may regulate plant response to metals ► Metal transport and localization in plants may be crucial for phytoremediation ABSTRACT Emissions of heavy metals have risen over the past 200 years and significantly exceed those from natural sources. Phytoremediation strategies may be able to recover soil productivity in self-sustaining ecosystems; however, our knowledge of the molecular mechanisms involved in plant heavy-metal perception and signalling is scarce. The aim of this study was to assemble a ``molecular tool box'' of genes useful for phytoremediation. To identify mutants with different heavy-metal-tolerance, we first selected a medium from mixtures containing three metals based on their presence in two Spanish mining areas and then screened about 7,000 lines of Arabidopsis T-DNA mutants and found 74 lines more resistant and 56 more susceptible than the wild type (WT). Classification of the genes showed that they were mainly linked to transport, protein modification and signalling, with RNA metabolism being the most representative category in the resistant phenotypes and protein metabolism in the sensitive ones. We have characterized one resistant mutant, Athpp9 and one sensitive, Atala4. These mutants showed differences in growth and metal translocation. Additionally, we found that these mutants keep their phenotype in amended former soils, suggesting that these genes may be useful for phytoremediation and the recovery of contaminated soils.

Research paper thumbnail of Expression of a peroxisome proliferator-activated receptor gene (xPPARα) from Xenopus laevis in tobacco (Nicotiana tabacum) plants

Planta, Jun 1, 2006

In this work, we have genetically transformed tobacco (Nicotiana tabacum) plants with the peroxis... more In this work, we have genetically transformed tobacco (Nicotiana tabacum) plants with the peroxisome proliferator-activated receptor cDNA (xPPARalpha) from Xenopus laevis, which is a transcriptional factor involved in the peroxisomal proliferation and induction of fatty acid beta-oxidation in animal cells. Several transgenic lines were generated and one representative line (T) from the R2 generation was selected for further studies. Analysis of free fatty acids revealed that unsaturated fatty acids such as C16:2 and C16:3 were deficient in line T, whereas saturated fatty acids like C16:0, C18:0, and C20:0 were more abundant than in non-transformed plants. Acyl-CoA oxidase (ACOX) activity was assayed as a marker enzyme of beta-oxidation in crude leaf extracts and it was found that in line T there was a threefold increase in enzyme activity. We also found that the peroxisome population was increased and that catalase (CAT) activity was induced by clofibrate, a known activator of xPPARalpha protein, in leaves from line T. Taken together, these findings suggest that xPPARalpha is functional in plants and that its expression in tobacco leads to changes in general lipid metabolism and peroxisomal proliferation as reported in animal cells. Furthermore, it indicates that there is an endogenous ligand in tobacco cells able to activate xPPARalpha.

Research paper thumbnail of cpFBPasell, a novel redox-independent chloroplastic isoform of fructose-1,6-bisphosphatase

Plant Cell and Environment, 2009

Research paper thumbnail of Cadmium Induced Changes in the Growth and Oxidative Metabolism of Green Gram-Vigna radiata Linn

Journal of Plant Biochemistry & Physiology, 2015

The effect of cadmium chloride on green gram (Vigna radiata Linn.) was studied using the paramete... more The effect of cadmium chloride on green gram (Vigna radiata Linn.) was studied using the parameters like carbohydrates, protein, chlorophyll and oxidative enzymes like superoxide dismutase, catalase and peroxidase of leaves in order to know the possible involvement of cadmium metal in the generation of oxidative stress. Results obtained in this work showed that the application of cadmium decreased the content of carbohydrate, protein, chlorophyll and superoxide dismutase, catalase and peroxidase, compared to the control plants.

Research paper thumbnail of Induced Resistance for Plant Defense

Research paper thumbnail of Constitutive arginine-dependent nitric oxide synthase activity in different organs of pea seedlings during plant development

Planta, 2006

Nitric oxide (NO) is an important signalling molecule in different animal and plant physiological... more Nitric oxide (NO) is an important signalling molecule in different animal and plant physiological processes. Little is known about its biological function in plants and on the enzymatic source or site of NO production during plant development. The endogenous NO production from L-arginine (NO synthase activity) was analyzed in leaves, stems and roots during plant development, using pea seedlings as a model. NOS activity was analyzed using a novel chemiluminescence-based assay which is more sensitive and specific than previous methods used in plant tissues. In parallel, NO accumulation was analyzed by confocal laser scanning microscopy using as fluorescent probes either DAF-2 DA or DAF-FM DA. A strong increase in NOS activity was detected in stems after 11 days growth, coinciding with the maximum stem elongation. The arginine-dependent NOS activity was constitutive and sensitive to aminoguanidine, a well-known irreversible inhibitor of animal NOS, and this NOS activity was differentially modulated depending on the plant organ and seedling developmental stage. In all tissues studied, NO was localized mainly in the vascular tissue (xylem) and epidermal cells and in root hairs. These loci of NO generation and accumulation suggest novel functions for NO in these cell types.

Research paper thumbnail of Antioxidative enzymes in cultivars of pepper plants with different sensitivity to cadmium

Plant Physiology and Biochemistry, 2002

... and plants which enters the environment mainly from industrial processes and phosphate fertil... more ... and plants which enters the environment mainly from industrial processes and phosphate fertilizers and then is ... Cadmium effect on growth and physiological parameters of pepper. ... ions in the nutrient solution produced a significant growth inhibition of pepper plants, measured as ...

Research paper thumbnail of Nitric oxide improves tolerance to arsenic stress in Isatis cappadocica desv. Shoots by enhancing antioxidant defenses

Chemosphere, 2019

Arsenic (As) is a toxic metalloid that severely hampers plant growth and also poses health risks ... more Arsenic (As) is a toxic metalloid that severely hampers plant growth and also poses health risks for humans through the food chain. Although nitric oxide (NO) is known to improve plant resistance to multiple stresses including metal toxicity, little is known about its role in the As tolerance of hyperaccumulator plants. This study investigates the role of the exogenously applied NO donor, sodium nitroprusside (SNP), in improving the As tolerance of Isatis cappadocica, which have been reported to hyperaccumulate As. Exposure to toxic As concentrations significantly increases NO production and causes damage to the cell membrane, as indicated by increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentration, thereby reducing plant growth. However, the addition of SNP improves growth and alleviates As-induced oxidative stress by enhancing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), as well as proline and thiol concentration, thereby confirming the beneficial role played by NO in enhancing As stress tolerance. Furthermore, the As-induced decrease in growth and the increase in oxidative stress were more marked in the presence of bovine hemoglobin (Hb; a NO scavenger) and N(G)-nitro-L-arginine methyl ester (L-NAME; a NO synthase inhibitor), thus demonstrating the protective role of NO against As toxicity. The reduction in NO concentration by L-NAME suggests that NOS-like activity is involved in the generation of NO in response to As in I. cappadocica.

Research paper thumbnail of Peroxisomes as a Cellular Source of ROS Signal Molecules

Signaling and Communication in Plants, 2009

Research paper thumbnail of Cadmium effect on oxidative metabolism of pea (Pisum sativum L.) roots. Imaging of reactive oxygen species and nitric oxide accumulation in vivo

Plant, Cell & Environment, 2006

ABSTRACTGrowth of pea (Pisum sativum L.) plants with 50 µm CdCl2 for 15 d produced a reduction in... more ABSTRACTGrowth of pea (Pisum sativum L.) plants with 50 µm CdCl2 for 15 d produced a reduction in the number and length of lateral roots, and changes in structure of the principal roots affecting the xylem vessels. Cadmium induced a reduction in glutathione (GSH) and ascorbate (ASC) contents, and catalase (CAT), GSH reductase (GR) and guaiacol peroxidase (GPX) activities. CuZn‐superoxide dismutase (SOD) activity was also diminished by the Cd treatment, although Mn‐SOD was slightly increased. CAT and CuZn‐SOD were down‐regulated at transcriptional level, while Mn‐SOD, Fe‐SOD and GR were up‐regulated. Analysis of reactive oxygen species (ROS) and nitric oxide (NO) levels by fluorescence and confocal laser microscopy (CLM) showed an over‐accumulation of O2.− and H2O2, and a reduction in the NO content in lateral and principal roots. ROS overproduction was dependent on changes in intracellular Ca+2 content, and peroxidases and NADPH oxidases were involved. Cadmium also produced an incre...

Research paper thumbnail of Plant proteases, protein degradation, and oxidative stress: role of peroxisomes

Plant Physiology and Biochemistry, 2002

Growth and development in all organisms occur as a result of an overall balance between synthesis... more Growth and development in all organisms occur as a result of an overall balance between synthesis and proteolysis. In plants, protein degradation is a crucial mechanism in some developmental stages such as germination, morphogenesis and cell biogenesis, senescence, and programmed cell death. In this work, the main proteases that take part in these processes are reviewed. Proteolysis is also an

Research paper thumbnail of Glutathione reductase from pea leaves: response to abiotic stress and characterization of the peroxisomal isozyme

New Phytologist, 2006

• The glutathione reductase (GR; EC 1.6.4.2) isozyme present in peroxisomes has been purified for... more • The glutathione reductase (GR; EC 1.6.4.2) isozyme present in peroxisomes has been purified for the first time, and its unequivocal localization in these organelles, by immunogold electron microscopy, is reported. • The enzyme was purified c. 21-fold with a specific activity of 9523 units mg − 1 protein, and a yield of 44 µg protein kg − 1 leaves was obtained. The subunit size of the peroxisomal GR was 56 kDa and the isoelectric point was 5.4. The enzyme was recognized by a polyclonal antibody raised against total GR from pea (Pisum sativum) leaves. • The localization of GR in peroxisomes adds to chloroplasts and mitochondria where GR isozymes are also present, and suggests a multiple targeting of this enzyme to distinct cell compartments depending on the metabolism of each organelle under the plant growth conditions. • The expression level of GR in several organs of pea plants and under different stress conditions was investigated. The possible role of peroxisomal GR under abiotic stress conditions, such as cadmium toxicity, high light, darkness, high temperature, wounding and low temperature, is discussed.

Research paper thumbnail of Immunocytochemical Localization of Copper, Zinc Superoxide Disrnutase in Peroxisomes from Wihermelon (Citrullus vulgarisSchrad.) Cotyledons

Free Radical Research, 1997

In previous works using cell fractionation methods we demonstrated the presence of a Cu,Zn-contai... more In previous works using cell fractionation methods we demonstrated the presence of a Cu,Zn-containing superoxide dismutase in peroxisomes from watermelon cotyledons. In this work, this intracellular localization was evaluated by using western blot and EM immunocytochemical analysis with a polyclonal antibody against peroxisomal Cu,Zn-SOD II from watermelon cotyledons. In crude extracts from 6-day old cotyledons, analysis by western blot showed two cross-reactivity bands which belonged to the isozymes Cu,Zn-SOD I and Cu,Zn-SOD II. In peroxisomes purified by sucrose density-gradient centrifugation only one cross-reactivity band was found in the peroxisomal matrix which corresponded to the isozyme Cu,Zn-SOD II. When SOD activity was assayed in purified peroxisomes two isozymes were detected, Cu,Zn-SOD II in the matrix, and a Mn-SOD in the membrane fraction which was removed by sodium carbonate washing. EM immunocytochemistry of Cu,Zn-SOD on sections of 6-day old cotyledons, showed that gold label was mainly localized over plastids and also in peroxisomes and the cytosol, whereas mitochondria did not label for Cu,Zn-SOD.

Research paper thumbnail of Peroxisomal Metabolism and Dynamics at the Crossroads Between Stimulus Perception and Fast Cell Responses to the Environment

Frontiers in Cell and Developmental Biology, 2020

Research paper thumbnail of Percoll reversibly inhibits superoxide dismutase

Revista española de fisiología, 1985

Incubation of pea leaf extracts (Pisum sativum L.) at 6 degrees C in isoosmotic media containing ... more Incubation of pea leaf extracts (Pisum sativum L.) at 6 degrees C in isoosmotic media containing different Percoll concentrations significantly represses the total superoxide dismutase (SOD) activity in a concentration- and time-dependent manner. After 24 h incubation at 6 degrees C, 30-45% Percoll concentrations bring about an inhibition of Mn-SOD activity of more than 50%. Isozyme Cu,Zn-SOD II is affected to a lesser extent, with a maximum inhibition of 36% at high Percoll concentrations, whereas isozyme Cu,Zn-SOD I undergoes only slight variations. However, dilution of the samples followed by electrophoresis completely removes the Percoll inhibitory action. Results suggest that superoxide dismutases could be adsorbed onto the Percoll surface through electrostatic interactions.

Research paper thumbnail of Peroxisomes, Reactive Oxygen Metabolism, and Stress-Related Enzyme Activities

Plant Peroxisomes, 2002

... On the contrary, peroxisomal manganese superoxide dismutase (EC 1.15. ... In these two cellul... more ... On the contrary, peroxisomal manganese superoxide dismutase (EC 1.15. ... In these two cellular organelles the production of superoxide radicals, and the induction of SOD isozymes in ... Conversely, the activity of glycolate oxidase was stimulated by NaCl in salt-tolerant plants. ...

Research paper thumbnail of Localization of Superoxide Dismutase in Glyoxysomes from Citrullus vulgaris. Functional Implications in Cellular Metabolism

Journal of Plant Physiology, 1987

ABSTRACT

Research paper thumbnail of Plant Peroxisomes, Reactive Oxygen Metabolism and Nitric Oxide

IUBMB Life, 2008

In plant cells, as in most eukaryotic organisms, peroxisomes are probably the major sites of intr... more In plant cells, as in most eukaryotic organisms, peroxisomes are probably the major sites of intracellular H2O2 production, as a result of their essentially oxidative type of metabolism. Like mitochondria and chloroplasts, peroxisomes also produce superoxide radicals (O2*-) and there are, at least, two sites of superoxide generation: one in the organelle matrix, the generating system being xanthine oxidase, and another site in the peroxisomal membranes dependent on NAD(P)H. In peroxisomal membranes, three integral polypeptides (PMPs) with molecular masses of 18, 29, and 32 kDa have been shown to generate O2*- radicals. Besides catalase, several antioxidative systems have been demonstrated in plant peroxisomes, including different superoxide dismutases, the four enzymes of the ascorbate-glutathione cycle plus ascorbate and glutathione, and three NADP-dependent dehydrogenases. A CuZn-SOD and two Mn-SODs have been purified and characterized from different types of plant peroxisomes. The presence of the enzyme nitric oxide synthase (NOS) and its reaction product, nitric oxide (NO*), has been recently demonstrated in plant peroxisomes. Different experimental evidence has suggested that peroxisomes have a ROS-mediated cellular function in leaf senescence and in stress situations induced by xenobiotics and heavy metals. Peroxisomes could also have a role in plant cells as a source of signal molecules like NO*, O2*- radicals, H2O2, and possibly S-nitrosoglutathione (GSNO). It seems reasonable to think that a signal molecule-producing function similar to that postulated for plant peroxisomes could also be performed by human, animal and yeast peroxisomes, where research on oxy radicals, antioxidants and nitric oxide is less advanced than in plant peroxisomes.

Research paper thumbnail of Nutritional Effect and Expression of SODs: Induction and Gene Expression; Diagnostics; Prospective Protection Against Oxygen Toxicity

Free Radical Research Communications, 1991

Research paper thumbnail of Nitric Oxide and Globin Glb1 Regulate Fusarium oxysporum Infection of Arabidopsis thaliana

Antioxidants

Plants continuously interact with fungi, some of which, such as Fusarium oxysporum, are lethal, l... more Plants continuously interact with fungi, some of which, such as Fusarium oxysporum, are lethal, leading to reduced crop yields. Recently, nitric oxide (NO) has been found to play a regulatory role in plant responses to F. oxysporum, although the underlying mechanisms involved are poorly understood. In this study, we show that Arabidopsis mutants with altered levels of phytoglobin 1 (Glb1) have a higher survival rate than wild type (WT) after infection with F. oxysporum, although all the genotypes analyzed exhibited a similar fungal burden. None of the defense responses that were analyzed in Glb1 lines, such as phenols, iron metabolism, peroxidase activity, or reactive oxygen species (ROS) production, appear to explain their higher survival rates. However, the early induction of the PR genes may be one of the reasons for the observed survival rate of Glb1 lines infected with F. oxysporum. Furthermore, while PR1 expression was induced in Glb1 lines very early on the response to F. oxy...

Research paper thumbnail of Screening Arabidopsis mutants in genes useful for phytoremediation

Journal of Hazardous Materials, 2017

<xps:span class="xps_Image">fx1 Highlights► A screening of 7,... more <xps:span class="xps_Image">fx1 Highlights► A screening of 7,000 mutants in a medium containing three heavy metals was done ► Protein metabolism and signalling mutants may regulate plant response to metals ► Metal transport and localization in plants may be crucial for phytoremediation ABSTRACT Emissions of heavy metals have risen over the past 200 years and significantly exceed those from natural sources. Phytoremediation strategies may be able to recover soil productivity in self-sustaining ecosystems; however, our knowledge of the molecular mechanisms involved in plant heavy-metal perception and signalling is scarce. The aim of this study was to assemble a ``molecular tool box'' of genes useful for phytoremediation. To identify mutants with different heavy-metal-tolerance, we first selected a medium from mixtures containing three metals based on their presence in two Spanish mining areas and then screened about 7,000 lines of Arabidopsis T-DNA mutants and found 74 lines more resistant and 56 more susceptible than the wild type (WT). Classification of the genes showed that they were mainly linked to transport, protein modification and signalling, with RNA metabolism being the most representative category in the resistant phenotypes and protein metabolism in the sensitive ones. We have characterized one resistant mutant, Athpp9 and one sensitive, Atala4. These mutants showed differences in growth and metal translocation. Additionally, we found that these mutants keep their phenotype in amended former soils, suggesting that these genes may be useful for phytoremediation and the recovery of contaminated soils.

Research paper thumbnail of Expression of a peroxisome proliferator-activated receptor gene (xPPARα) from Xenopus laevis in tobacco (Nicotiana tabacum) plants

Planta, Jun 1, 2006

In this work, we have genetically transformed tobacco (Nicotiana tabacum) plants with the peroxis... more In this work, we have genetically transformed tobacco (Nicotiana tabacum) plants with the peroxisome proliferator-activated receptor cDNA (xPPARalpha) from Xenopus laevis, which is a transcriptional factor involved in the peroxisomal proliferation and induction of fatty acid beta-oxidation in animal cells. Several transgenic lines were generated and one representative line (T) from the R2 generation was selected for further studies. Analysis of free fatty acids revealed that unsaturated fatty acids such as C16:2 and C16:3 were deficient in line T, whereas saturated fatty acids like C16:0, C18:0, and C20:0 were more abundant than in non-transformed plants. Acyl-CoA oxidase (ACOX) activity was assayed as a marker enzyme of beta-oxidation in crude leaf extracts and it was found that in line T there was a threefold increase in enzyme activity. We also found that the peroxisome population was increased and that catalase (CAT) activity was induced by clofibrate, a known activator of xPPARalpha protein, in leaves from line T. Taken together, these findings suggest that xPPARalpha is functional in plants and that its expression in tobacco leads to changes in general lipid metabolism and peroxisomal proliferation as reported in animal cells. Furthermore, it indicates that there is an endogenous ligand in tobacco cells able to activate xPPARalpha.

Research paper thumbnail of cpFBPasell, a novel redox-independent chloroplastic isoform of fructose-1,6-bisphosphatase

Plant Cell and Environment, 2009

Research paper thumbnail of Cadmium Induced Changes in the Growth and Oxidative Metabolism of Green Gram-Vigna radiata Linn

Journal of Plant Biochemistry & Physiology, 2015

The effect of cadmium chloride on green gram (Vigna radiata Linn.) was studied using the paramete... more The effect of cadmium chloride on green gram (Vigna radiata Linn.) was studied using the parameters like carbohydrates, protein, chlorophyll and oxidative enzymes like superoxide dismutase, catalase and peroxidase of leaves in order to know the possible involvement of cadmium metal in the generation of oxidative stress. Results obtained in this work showed that the application of cadmium decreased the content of carbohydrate, protein, chlorophyll and superoxide dismutase, catalase and peroxidase, compared to the control plants.

Research paper thumbnail of Induced Resistance for Plant Defense

Research paper thumbnail of Constitutive arginine-dependent nitric oxide synthase activity in different organs of pea seedlings during plant development

Planta, 2006

Nitric oxide (NO) is an important signalling molecule in different animal and plant physiological... more Nitric oxide (NO) is an important signalling molecule in different animal and plant physiological processes. Little is known about its biological function in plants and on the enzymatic source or site of NO production during plant development. The endogenous NO production from L-arginine (NO synthase activity) was analyzed in leaves, stems and roots during plant development, using pea seedlings as a model. NOS activity was analyzed using a novel chemiluminescence-based assay which is more sensitive and specific than previous methods used in plant tissues. In parallel, NO accumulation was analyzed by confocal laser scanning microscopy using as fluorescent probes either DAF-2 DA or DAF-FM DA. A strong increase in NOS activity was detected in stems after 11 days growth, coinciding with the maximum stem elongation. The arginine-dependent NOS activity was constitutive and sensitive to aminoguanidine, a well-known irreversible inhibitor of animal NOS, and this NOS activity was differentially modulated depending on the plant organ and seedling developmental stage. In all tissues studied, NO was localized mainly in the vascular tissue (xylem) and epidermal cells and in root hairs. These loci of NO generation and accumulation suggest novel functions for NO in these cell types.

Research paper thumbnail of Antioxidative enzymes in cultivars of pepper plants with different sensitivity to cadmium

Plant Physiology and Biochemistry, 2002

... and plants which enters the environment mainly from industrial processes and phosphate fertil... more ... and plants which enters the environment mainly from industrial processes and phosphate fertilizers and then is ... Cadmium effect on growth and physiological parameters of pepper. ... ions in the nutrient solution produced a significant growth inhibition of pepper plants, measured as ...

Research paper thumbnail of Nitric oxide improves tolerance to arsenic stress in Isatis cappadocica desv. Shoots by enhancing antioxidant defenses

Chemosphere, 2019

Arsenic (As) is a toxic metalloid that severely hampers plant growth and also poses health risks ... more Arsenic (As) is a toxic metalloid that severely hampers plant growth and also poses health risks for humans through the food chain. Although nitric oxide (NO) is known to improve plant resistance to multiple stresses including metal toxicity, little is known about its role in the As tolerance of hyperaccumulator plants. This study investigates the role of the exogenously applied NO donor, sodium nitroprusside (SNP), in improving the As tolerance of Isatis cappadocica, which have been reported to hyperaccumulate As. Exposure to toxic As concentrations significantly increases NO production and causes damage to the cell membrane, as indicated by increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentration, thereby reducing plant growth. However, the addition of SNP improves growth and alleviates As-induced oxidative stress by enhancing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), as well as proline and thiol concentration, thereby confirming the beneficial role played by NO in enhancing As stress tolerance. Furthermore, the As-induced decrease in growth and the increase in oxidative stress were more marked in the presence of bovine hemoglobin (Hb; a NO scavenger) and N(G)-nitro-L-arginine methyl ester (L-NAME; a NO synthase inhibitor), thus demonstrating the protective role of NO against As toxicity. The reduction in NO concentration by L-NAME suggests that NOS-like activity is involved in the generation of NO in response to As in I. cappadocica.

Research paper thumbnail of Peroxisomes as a Cellular Source of ROS Signal Molecules

Signaling and Communication in Plants, 2009

Research paper thumbnail of Cadmium effect on oxidative metabolism of pea (Pisum sativum L.) roots. Imaging of reactive oxygen species and nitric oxide accumulation in vivo

Plant, Cell & Environment, 2006

ABSTRACTGrowth of pea (Pisum sativum L.) plants with 50 µm CdCl2 for 15 d produced a reduction in... more ABSTRACTGrowth of pea (Pisum sativum L.) plants with 50 µm CdCl2 for 15 d produced a reduction in the number and length of lateral roots, and changes in structure of the principal roots affecting the xylem vessels. Cadmium induced a reduction in glutathione (GSH) and ascorbate (ASC) contents, and catalase (CAT), GSH reductase (GR) and guaiacol peroxidase (GPX) activities. CuZn‐superoxide dismutase (SOD) activity was also diminished by the Cd treatment, although Mn‐SOD was slightly increased. CAT and CuZn‐SOD were down‐regulated at transcriptional level, while Mn‐SOD, Fe‐SOD and GR were up‐regulated. Analysis of reactive oxygen species (ROS) and nitric oxide (NO) levels by fluorescence and confocal laser microscopy (CLM) showed an over‐accumulation of O2.− and H2O2, and a reduction in the NO content in lateral and principal roots. ROS overproduction was dependent on changes in intracellular Ca+2 content, and peroxidases and NADPH oxidases were involved. Cadmium also produced an incre...

Research paper thumbnail of Plant proteases, protein degradation, and oxidative stress: role of peroxisomes

Plant Physiology and Biochemistry, 2002

Growth and development in all organisms occur as a result of an overall balance between synthesis... more Growth and development in all organisms occur as a result of an overall balance between synthesis and proteolysis. In plants, protein degradation is a crucial mechanism in some developmental stages such as germination, morphogenesis and cell biogenesis, senescence, and programmed cell death. In this work, the main proteases that take part in these processes are reviewed. Proteolysis is also an

Research paper thumbnail of Glutathione reductase from pea leaves: response to abiotic stress and characterization of the peroxisomal isozyme

New Phytologist, 2006

• The glutathione reductase (GR; EC 1.6.4.2) isozyme present in peroxisomes has been purified for... more • The glutathione reductase (GR; EC 1.6.4.2) isozyme present in peroxisomes has been purified for the first time, and its unequivocal localization in these organelles, by immunogold electron microscopy, is reported. • The enzyme was purified c. 21-fold with a specific activity of 9523 units mg − 1 protein, and a yield of 44 µg protein kg − 1 leaves was obtained. The subunit size of the peroxisomal GR was 56 kDa and the isoelectric point was 5.4. The enzyme was recognized by a polyclonal antibody raised against total GR from pea (Pisum sativum) leaves. • The localization of GR in peroxisomes adds to chloroplasts and mitochondria where GR isozymes are also present, and suggests a multiple targeting of this enzyme to distinct cell compartments depending on the metabolism of each organelle under the plant growth conditions. • The expression level of GR in several organs of pea plants and under different stress conditions was investigated. The possible role of peroxisomal GR under abiotic stress conditions, such as cadmium toxicity, high light, darkness, high temperature, wounding and low temperature, is discussed.

Research paper thumbnail of Immunocytochemical Localization of Copper, Zinc Superoxide Disrnutase in Peroxisomes from Wihermelon (Citrullus vulgarisSchrad.) Cotyledons

Free Radical Research, 1997

In previous works using cell fractionation methods we demonstrated the presence of a Cu,Zn-contai... more In previous works using cell fractionation methods we demonstrated the presence of a Cu,Zn-containing superoxide dismutase in peroxisomes from watermelon cotyledons. In this work, this intracellular localization was evaluated by using western blot and EM immunocytochemical analysis with a polyclonal antibody against peroxisomal Cu,Zn-SOD II from watermelon cotyledons. In crude extracts from 6-day old cotyledons, analysis by western blot showed two cross-reactivity bands which belonged to the isozymes Cu,Zn-SOD I and Cu,Zn-SOD II. In peroxisomes purified by sucrose density-gradient centrifugation only one cross-reactivity band was found in the peroxisomal matrix which corresponded to the isozyme Cu,Zn-SOD II. When SOD activity was assayed in purified peroxisomes two isozymes were detected, Cu,Zn-SOD II in the matrix, and a Mn-SOD in the membrane fraction which was removed by sodium carbonate washing. EM immunocytochemistry of Cu,Zn-SOD on sections of 6-day old cotyledons, showed that gold label was mainly localized over plastids and also in peroxisomes and the cytosol, whereas mitochondria did not label for Cu,Zn-SOD.