Publications by authors named "Ana Furlan"

16 Publications

  • Page 1 of 1

NaSO and NaCl salts differentially modulate the antioxidant systems in the highly stress tolerant halophyte Prosopis strombulifera.

Plant Physiol Biochem 2021 Sep 9;167:748-762. Epub 2021 Sep 9.

Laboratorio de Fisiología Vegetal Interacción Planta-Ambiente, Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina; Instituto de Investigaciones Agrobiotecnológicas (INIAB-UNRC)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Río Cuarto, Córdoba, Argentina.

Prosopis strombulifera (Lam.) Benth. is a halophytic shrub abundant in high-salinity areas in central Argentina, with high tolerance against NaCl but strong growth inhibition by NaSO. In the present study, the modulation of the antioxidant systems (enzymatic and non-enzymatic components) was analyzed under different salt treatments (NaCl, NaSO and the iso-osmotic mixture) in hydroponic cultivation. NaSO-treated plants showed strong indications of oxidative stress (HO and O-• increase). Modifications in antioxidant enzymes activities were observed mainly under NaSO treatment, where CAT seems to play an important role in early detoxification of HO in roots, whereas SOD and APX have a predominant role in leaves. As part of the non-enzymatic system, 21 compounds were identified in leaves, being polyphenols the most abundant. Control plants contained the major variety of detected phytochemicals (14). NaSO-treated plants contained 10 compounds and NaCl-treated plants nine compounds, but with a different profile. NaCl-treated plants showed the highest antioxidant capacity. Our findings confirm that different types of salt treatments provoke a differential modulation of the antioxidant systems. Polyphenols and other ROS-detoxifying compounds, in a joint action with the enzymatic antioxidant system, are proposed to have a fundamental role in the cellular protection of P. strombulifera plants under severe oxidative stress. Our findings also highlight the potential of this halophyte as a valuable source of bioactive compounds with high antioxidant activity and health benefits.
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http://dx.doi.org/10.1016/j.plaphy.2021.09.003DOI Listing
September 2021

Targeting redox metabolism of the maize-Azospirillum brasilense interaction exposed to arsenic-affected groundwater.

Physiol Plant 2021 Jul 30. Epub 2021 Jul 30.

Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas (INIAB-CONICET), Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Córdoba, Argentina.

Arsenic in groundwater constitutes an agronomic problem due to its potential accumulation in the food chain. Among the agro-sustainable tools to reduce metal(oid)s toxicity, the use of plant growth-promoting bacteria (PGPB) becomes important. For that, and based on previous results in which significant differences of As translocation were observed when inoculating maize plants with Az39 or CD Azospirillum strains, we decided to decipher the redox metabolism changes and the antioxidant system response of maize plants inoculated when exposed to a realistic arsenate (As ) dose. Results showed that As caused morphological changes in the root exodermis. Photosynthetic pigments decreased only in CD inoculated plants, while oxidative stress evidence was detected throughout the plant, regardless of the assayed strain. The antioxidant response was strain-differential since only CD inoculated plants showed an increase in superoxide dismutase, glutathione S-transferase (GST), and glutathione reductase (GR) activities while other enzymes showed the same behavior irrespective of the inoculated strain. Gene expression assays reported that only GST23 transcript level was upregulated by arsenate, regardless of the inoculated strain. As diminished the glutathione (GSH) content of roots inoculated with the Az39 strain, and CD inoculated plants showed a decrease of oxidized GSH (GSSG) levels. We suggest a model in which the antioxidant response of the maize-diazotrophs system is modulated by the strain and that GSH plays a central role acting mainly as a substrate for GST. These findings generate knowledge for a suitable PGPB selection, and its scaling to an effective bioinoculant formulation for maize crops exposed to adverse environmental conditions.
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http://dx.doi.org/10.1111/ppl.13514DOI Listing
July 2021

Unraveling the impact of arsenic on the redox response of peanut plants inoculated with two different Bradyrhizobium sp. strains.

Chemosphere 2020 Nov 21;259:127410. Epub 2020 Jun 21.

Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas (INIAB-CONICET), Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta 36, Km 601, X5800, Río Cuarto, Córdoba, Argentina. Electronic address:

Arsenic (As) can be present naturally in groundwater from peanut fields, constituting a serious problem, as roots can accumulate and mobilize the metalloid to their edible parts. Understanding the redox changes in the legume exposed to As may help to detect potential risks to human health and recognize tolerance mechanisms. Thirty-days old peanut plants inoculated with Bradyrhizobium sp. strains (SEMIA6144 or C-145) were exposed to a realistic arsenate concentration, in order to unravel the redox response and characterize the oxidative stress indexes. Thus, root anatomy, reactive oxygen species detection by fluorescence microscopy and, ROS histochemical staining along with the NADPH oxidase activity were analyzed. Besides, photosynthetic pigments and damage to lipids and proteins were determined as oxidative stress indicators. Results showed that at 3 μM As, the cross-section areas of peanut roots were augmented; NADPH oxidase activity was significantly increased and O˙¯and HO accumulated in leaves and roots. Likewise, an increase in the lipid peroxidation and protein carbonyls was also observed throughout the plant regardless the inoculated strain, while chlorophylls and carotenes were increased only in those inoculated with Bradyrhizobium sp. C-145. Interestingly, the oxidative burst, mainly induced by the NADPH oxidase activity, and the consequent oxidative stress was strain-dependent and organ-differential. Additionally, As modifies the root anatomy, acting as a possibly first defense mechanism against the metalloid entry. All these findings allowed us to conclude that the redox response of peanut is conditioned by the rhizobial strain, which contributes to the importance of effectively formulating bioinoculants for this crop.
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http://dx.doi.org/10.1016/j.chemosphere.2020.127410DOI Listing
November 2020

Proline metabolic dynamics and implications in drought tolerance of peanut plants.

Plant Physiol Biochem 2020 Jun 17;151:566-578. Epub 2020 Apr 17.

Department of Biochemistry, Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.

Proline accumulation and metabolism are associated with mechanisms of abiotic stress avoidance in plants. Proline accumulation generally improves osmotic stress tolerance whereas proline metabolism can have varying effects from ATP generation to the formation of reactive oxygen species. To further understand the roles of proline in stress protection, two peanut cultivars with contrasting tolerance to drought were examined by transcriptional and biochemical analyses during water stress. Plants exposed to polyethylene glycol had diminished relative water content and increased proline content; while, only the drought sensitive plants, cultivar Granoleico, showed lipid oxidative damage (measured as thiobarbituric acid reactive substances). The expression of proline biosynthesis genes (P5CS1, P5CS2a, P5CS2b, P5CR) was increased in both cultivars upon exposure to water stress. However, the relative expression of proline catabolism genes (ProDH1, ProDH2) was increased only in the sensitive cultivar during stress. Exogenous addition of proline and the proline analogue thiazolidine-4-carboxylic acid (T4C), both substrates of proline dehydrogenase, was also used to exacerbate and identify plant responses. Pretreatment of plants with T4C induced unique changes in the drought tolerant EC-98 cultivar such as higher mRNA levels of proline biosynthetic and catabolic ProDH genes, even in the absence of water stress. The increased levels of ProDH gene expression, potentially associated with higher T4C conversion to cysteine, may contribute to the tolerant phenotype.
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http://dx.doi.org/10.1016/j.plaphy.2020.04.010DOI Listing
June 2020

Are psychogenic nonepileptic seizures risk factors for a worse outcome in patients with refractory mesial temporal epilepsy submitted to surgery? Results of a retrospective cohort study.

Epilepsy Behav 2019 04 16;93:12-15. Epub 2019 Feb 16.

Department of Psychiatry and Medical Psychology, Faculdade de Medicina de São José do Rio Preto (FAMERP), Brazil. Electronic address:

Objective: The objective of this study was to verify if the presence of psychogenic nonepileptic seizures (PNES) could be a risk factor precluding corticoamygdalohippocampectomy (CAH) in patients with refractory temporal lobe epilepsy (TLE) and mesial temporal sclerosis (MTS) (TLE-MTS).

Methods: This retrospective cohort study analyzed medical data of patients with refractory TLE-MTS accompanied in a Brazilian epilepsy surgery center. Presurgical psychiatric evaluations were performed using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria. Engel's I classification two years after surgery was considered as a favorable outcome.

Results: Of the 81 patients initially included (65 females; 56.5%), 49 (60.5%) had TLE-MTS without PNES, 24 (29.7%) with TLE-MTS and PNES, and eight (9.8%) with PNES only, who were excluded from further statistical comparisons. Nine patients with PNES (37.5%) underwent CAH versus 35 (71.4%) without PNES (p = 0.005). Five patients (55.5%) with PNES versus 26 (74.3%) without PNES presented Engel I (p = 0.54). The relative risk (RR) was of 1.90 for patients without PNES to undergo CAH and of 1.33 to be at Engel I.

Conclusions: In this study, PNES were associated with less CAH. There were no differences, however, regarding favorable postsurgical outcomes. These results highlight that the sole presence of PNES should not preclude CAH in patients with TLE-MTS, despite the necessity of careful presurgical psychiatric evaluation.
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http://dx.doi.org/10.1016/j.yebeh.2019.01.036DOI Listing
April 2019

Effects of a psychotherapeutic group intervention in patients with refractory mesial temporal lobe epilepsy and comorbid psychogenic nonepileptic seizures: A nonrandomized controlled study.

Seizure 2018 May 27;58:22-28. Epub 2018 Mar 27.

Faculdade de Medicina de São José do Rio Preto (FAMERP), Brazil. Electronic address:

Purpose: Psychogenic nonepileptic seizures (PNES) are paroxysmal episodes superficially resembling epileptic seizures but are not associated with any electrical abnormalities. Despite the existence of recent evidence addressing psychological interventions on PNES, there is a scarcity of studies investigating such interventions on patients with dual diagnoses, such as in temporal lobe epilepsy/mesial temporal sclerosis (TLE-MTS) with comorbid PNES; TLE-MTS is a very frequent epilepsy syndrome found in tertiary centers. We aimed to investigate the effects of a group psychotherapeutic intervention program based on cognitive-behavioral therapy (CBT) on patients dually diagnosed with TLE-MTS and PNES treated in a tertiary center.

Method: Patients with TLE-MTS and PNES who were followed-up in a tertiary center were invited. The intervention consisted of eight weekly, semi-structured group meetings. The Brazilian versions of the Quality of Life Scale (SF-36), the Toronto Alexithymia Scale (TAS), the Hamilton Depression Scale (HAM-D), the Hamilton Anxiety Scale (HAM-A), and the Ways of Coping Checklist (WCC) were applied before and after the intervention.

Results: Forty-seven patients were enrolled (25 females; 53.2%). Psychiatric disorders (PD) were observed in all 47 patients (100%); Major Depressive Disorder (MDD) was the most frequent PD (24; 51.0%). There were improvements on quality of life (P = 0.003), decreased depression (P<0.0001) and anxiety symptoms (P = 0.02), decreased levels of alexithymia (P = 0.02) and a reduction in seizure frequency (P = 0.02) after the intervention.

Conclusions: Present data suggest a positive impact of a group psychological intervention based on CBT in patients with TLE-MTS and PNES, highlighting this therapeutic possibility for this specific subgroup.
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http://dx.doi.org/10.1016/j.seizure.2018.03.023DOI Listing
May 2018

Gender differences in prevalence of psychiatric disorders, levels of alexithymia, and coping strategies in patients with refractory mesial temporal epilepsy and comorbid psychogenic nonepileptic seizures.

Epilepsy Behav 2018 05 22;82:1-5. Epub 2018 Mar 22.

Faculdade de Medicina de São José do Rio Preto (FAMERP), Brazil. Electronic address:

Objective: The objective of this study was to investigate the psychological aspects and psychiatric disorders (PDs) in patients dually diagnosed with refractory temporal lobe epilepsy and mesial temporal sclerosis (TLE-MTS) with psychogenic nonepileptic seizures (PNES) treated in a tertiary center in order to find any gender differences in psychiatric, clinical, and sociodemographic characteristics.

Method: Psychiatric assessment was performed through the Diagnostic and Statistical Manual for Psychiatric Disorders - 5th edition (DSM-5). The Brazilian versions of the Medical Outcomes Study 36 (SF-36), Toronto Alexithymia Scale (TAS-20), Hamilton Depression Scale (HAM-D), Hamilton Anxiety Scale (HAM-A), and Ways of Coping Checklist (WCC) were applied.

Results: Of the 47 patients enrolled (25 females; 53.2%), females were significantly more likely to have a history of previous psychiatric treatment (P=0.02), family history of epilepsy (P=0.01), and family history of PD (P=0.03). They also presented earlier onset of PNES (P=0.01) and higher PNES duration (P=0.02) compared with males. Major depressive disorder (MDD) was the most frequent PD (24; 51.0%). Females presented more psychiatric diagnoses (P<0.001), more diagnoses of MDD (P<0.001), and posttraumatic stress disorder (PTSD) (P<0.001). Several differences regarding quality of life, levels of alexithymia, anxiety/depressive symptoms, and coping strategies were observed between groups.

Conclusions: There are significant gender differences in psychiatric, clinical, and sociodemographic aspects in a group of patients with TLE-MTS and PNES, as well as in quality of life, levels of alexithymia, anxiety/depressive symptoms, and coping strategies. These gender differences suggest that specific approaches might be adopted depending on the patient's gender and, consequently, their distinct psychological/psychiatric profile.
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http://dx.doi.org/10.1016/j.yebeh.2018.02.026DOI Listing
May 2018

Oxidative stress in patients with refractory temporal lobe epilepsy and mesial temporal sclerosis: Possible association with major depressive disorder?

Epilepsy Behav 2018 03 3;80:191-196. Epub 2018 Feb 3.

Department of Chemistry and Environmental Sciences - IBILCE, Universidade Estadual Paulista (UNESP), São Paulo, Brazil.

Objective: The objective was to evaluate the genetic and biochemical profiles associated with oxidative stress (OS) in patients with temporal lobe epilepsy with mesial temporal sclerosis (TLE-MTS) and a healthy control group, and also to verify the possible existence of association between OS markers and psychiatric disorders (PD) in group with TLE-MTS.

Methods: Forty-six patients with refractory TLE-MTS and 112 healthy controls were included. Psychiatric evaluation occurred through Diagnostical and Statistical Manual of Mental Disorders (DSM-5) criteria. A peripheral blood sample was collected for analysis of glutathione S-transferase (GST) T1/M1 polymorphisms and serum levels of malondialdehyde (MDA) and antioxidant capacity equivalent to the trolox (TEAC), serum markers of OS. Student's t-test, Fisher's exact test, Chi-square test, and Analysis of Variance (ANOVA) were used, with a significance level of P<0.05.

Results: The PD were observed in 27 patients of the group with TLE-MTS (58.6%); major depressive disorder (MDD) was the most frequent. Serum levels of MDA (P<0.0001) and TEAC (P<0.0001) were higher in group with TLE-MTS. When patients with MDD were compared with patients without PD, significant differences were observed between MDA (P=0.002) and TEAC (P=0.003) serum levels. Patients with TLE-MTS and MDD presented higher levels when compared with patients with TLE-MTS without PD and with another PD except MDD.

Conclusions: The present study observed significantly higher serum levels of MDA and of TEAC in patients with refractory TLE-MTS in comparison with the control group. The MDD was observed as an important issue associated with higher OS levels in refractory TLE-MTS. Further studies are needed to investigate the association of OS, TLE-MTS, and PD.
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http://dx.doi.org/10.1016/j.yebeh.2017.12.025DOI Listing
March 2018

Metabolic features involved in drought stress tolerance mechanisms in peanut nodules and their contribution to biological nitrogen fixation.

Plant Sci 2017 Oct 30;263:12-22. Epub 2017 Jun 30.

Biochemistry and Physiology of Plants, Bielefeld University, D-33501 Bielefeld, Germany.

Legumes belong to the most important crops worldwide. They increase soil fertility due their ability to establish symbiotic associations with soil microorganisms, known as rhizobia, capable of fixing nitrogen from the atmosphere. However, they are frequently exposed to abiotic stress conditions in particular drought. Such adverse conditions impair the biological nitrogen fixation (BNF) and depend largely on the legume. Therefore, two peanut cultivars with contrasting tolerance to drought, namely the more tolerant EC-98 and the sensitive Granoleico, were investigated to elucidate the relative contribution of BNF to the tolerance to drought. The tolerant cultivar EC-98 sustained growth and BNF similar to the control condition despite the reduced water potential and photosynthesis, suggesting the functioning of distinct metabolic pathways that contributed to enhance the tolerance. The biochemical and metabolomics approaches revealed that nodules from the tolerant cultivar accumulated trehalose, proline and gamma-aminobutyric acid (GABA), metabolites with known function in protecting against drought stress. The amide metabolism was severely affected in nodules from the sensitive cultivar Granoleico as revealed by the low content of asparagine and glutamine in the drought stressed plants. The sensitive cultivar upon rehydration was unable to re-establish a metabolism similar to well-watered plants. This was evidenced by the low level of metabolites and, transcripts and specific activities of enzymes from the carbon (sucrose synthase) and nitrogen (glutamine synthetase) metabolism which decreased below the values of control plants. Therefore, the increased content of metabolites with protective functions under drought stress likely is crucial for the full restoration upon rehydration. Smaller changes of drought stress-related metabolites in nodule are another trait that contributes to the effective control of BNF in the tolerant peanut cultivar (EC-98).
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http://dx.doi.org/10.1016/j.plantsci.2017.06.009DOI Listing
October 2017

Antioxidant responses of peanut roots exposed to realistic groundwater doses of arsenate: Identification of glutathione S-transferase as a suitable biomarker for metalloid toxicity.

Chemosphere 2017 Aug 24;181:551-561. Epub 2017 Apr 24.

Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 Km 601, 5800 Río Cuarto, Córdoba, Argentina.

Arsenic (As)-polluted groundwater constitutes a serious problem for peanut plants, as roots can accumulate the metalloid in their edible parts. Characterization of stress responses to As may help to detect potential risks and identify mechanisms of tolerance, being the induction of oxidative stress a key feature. Fifteen-day old peanut plants were treated with arsenate in order to characterize the oxidative stress indexes and antioxidant response of the legume under realistic groundwater doses of the metalloid. Superoxide anion (O) and hydrogen peroxide (HO) histochemical staining along with the activities of NADPH oxidase, superoxide dismutase (SOD), catalase (CAT) and thiol (glutathione and thioredoxins) metabolism were determined in roots. Results showed that at 20 μM HAsO, peanut growth was reduced and the root architecture was altered. O and HO accumulated at the root epidermis, while lipid peroxidation, NADPH oxidase, SOD, CAT and glutathione S-transferase (GST) activities augmented. These variables increased with increasing As concentration (100 μM) while glutathione reductase (GR) and glutathione peroxidase/peroxiredoxin (GPX/PRX) were significantly decreased. These findings demonstrated that the metalloid induced physiological and biochemical alterations, being the NADPH oxidase enzyme implicated in the oxidative burst. Additionally, the strong induction of GST activity, even at the lowest HAsO doses studied, can be exploited as suitable biomarker of As toxicity in peanut plants, which may help to detect risks of As accumulation and select tolerant cultivars.
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http://dx.doi.org/10.1016/j.chemosphere.2017.04.104DOI Listing
August 2017

Dynamic responses of photosynthesis and the antioxidant system during a drought and rehydration cycle in peanut plants.

Funct Plant Biol 2016 Apr;43(4):337-345

Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36, Km. 601, 5800 Río Cuarto, Córdoba, Argentina.

Drought stress is one of the most important environmental factors that adversely affect the productivity and quality of crops. Most studies focus on elucidating plant responses to this stress but the reversibility of these effects is less known. The aim of this work was to evaluate whether drought-stressed peanut (Arachis hypogaea L.) plants were capable of recovering their metabolism upon rehydration, with a focus on their antioxidant system. Peanut plants in the flowering phase (30 days after sowing) were exposed to drought stress by withholding irrigation during 14 days and subsequent rehydration during 3 days. Under these conditions, physiological status indicators, reactive oxygen species production and antioxidant system activity were evaluated. Under drought stress, the stomatal conductance, photosynthetic quantum yield and 13C:12C ratio of the peanut plants were negatively affected, and also they accumulated reactive oxygen species. The antioxidant system of peanut plants showed increases in superoxide dismutase-, ascorbate peroxidase- and glutathione reductase-specific activities, as well as the total ascorbate content. All of these responses were reversed upon rehydration at 3 days. The efficient and dynamic regulation of variables related to photosynthesis and the antioxidant system during a drought and rehydration cycle in peanut plants was demonstrated. It is suggested that the activation of the antioxidant system could mediate the signalling of drought stress responses that enable the plant to survive and recover completely within 3 days of rehydration.
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http://dx.doi.org/10.1071/FP15206DOI Listing
April 2016

Psychiatric disorders as "hidden" contraindications for presurgical VEEG in patients with refractory epilepsy: A retrospective cohort study in a tertiary center.

Epilepsy Behav 2015 Apr 21;45:35-8. Epub 2015 Mar 21.

Department of Neurological Sciences, Faculdade de Medicina de São José do Rio Preto (FAMERP), São Paulo, Brazil.

Given the high frequency of psychiatric disorders (PDs) observed among patients with epilepsy, studies have highlighted the necessity of psychiatric evaluation for these patients, especially for those with refractory temporal lobe epilepsy with mesial temporal sclerosis (TLE-MTS) who are surgical candidates. Current evidence highlights the safety of video-electroencephalography (VEEG) as a means of investigation in patients with TLE-MTS and PDs. However, the presence of such disorders has still been seen as a contraindication for presurgical evaluation with VEEG in some epilepsy centers mainly because of the risk of negative behavioral events. The present retrospective cohort study performed in a Brazilian tertiary epilepsy center aimed to identify whether the presence of a PD remains a contraindication for presurgical VEEG. Clinical, sociodemographic, and psychiatric data from 41 patients who underwent VEEG as part of their presurgical evaluation were compared to data from 32 patients with refractory TLE-MTS who had not undergone VEEG. Psychiatric diagnoses were determined using the DSM-IV and ILAE criteria. Psychiatric disorders were diagnosed in 34 patients (46.6%). Major depressive disorder was the most frequent PD and was observed in 22 patients (30.1%). Anxiety disorders were observed in 14 patients (19.2%). Of the 41 patients (56.2%) who underwent presurgical VEEG, only 12 (29.2%) were found to have a PD during the presurgical psychiatric evaluation compared to 22 of the 32 (68.7%) who did not undergo VEEG (p=0.001; RR=2.35). The present findings suggest that the presence of a PD alone should not be a contraindication for VEEG monitoring and epilepsy surgery.
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http://dx.doi.org/10.1016/j.yebeh.2015.02.026DOI Listing
April 2015

Physiological responses of a halophytic shrub to salt stress by Na2SO4 and NaCl: oxidative damage and the role of polyphenols in antioxidant protection.

AoB Plants 2014 Jul 24;6. Epub 2014 Jul 24.

Fisiología Vegetal, Físico Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina

Salt stress conditions lead to increased production of reactive oxygen species (ROS) in plant cells. Halophytes have the ability to reduce these toxic ROS by means of a powerful antioxidant system that includes enzymatic and non-enzymatic components. In this research, we used the halophytic shrub Prosopis strombulifera to investigate whether the ability of this species to grow under increasing salt concentrations and mixtures was related to the synthesis of polyphenolic compounds and to the maintenance of leaf pigment contents for an adequate photosynthetic activity. Seedlings of P. strombulifera were grown hydroponically in Hoagland's solution, gradually adding Na2SO4 and NaCl separately or in mixtures until reaching final osmotic potentials of -1, -1.9 and -2.6 MPa. Control plants were allowed to develop in Hoagland's solution without salt. Oxidative damage in tissues was determined by H2O2 and malondialdehyde content. Leaf pigment analysis was performed by high-performance liquid chromatography with ultraviolet, and total phenols, total flavonoids, total flavan-3-ols, condensed tannins, tartaric acid esters and flavonols were spectrophotometrically assayed. Treatment with Na2SO4 increased H2O2 production and lipid peroxidation in tissues and induced a sharp increase in flavonoid compounds (mainly flavan-3-ols) and consequently in the antioxidant activity. Also, Na2SO4 treatment induced an increased carotenoid/chlorophyll ratio, which may represent a strategy to protect photosystems against photooxidation. NaCl treatment, however, did not affect H2O2 content, lipid peroxidation, pigments or polyphenols synthesis. The significant accumulation of flavonoids in tissues under Na2SO4 treatment and their powerful antioxidant activity indicates a role for these compounds in counteracting the oxidative damage induced by severe salt stress, particularly, ionic stress. We demonstrate that ionic interactions between different salts in salinized soils modify the biochemical and morpho-physiological responses of P. strombulifera plants to salinity.
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http://dx.doi.org/10.1093/aobpla/plu042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4153985PMC
July 2014

Antioxidant enzyme activities and gene expression patterns in peanut nodules during a drought and rehydration cycle.

Funct Plant Biol 2014 Jul;41(7):704-713

Biochemistry and Physiology of Plants, Bielefeld University, D-33501 Bielefeld, Germany.

Drought stress is one of the most important environmental factors that affect plant growth and limit biomass production. Most studies focus on drought stress development but the reversibility of the effects receives less attention. Therefore, the present work aims to explore the biological nitrogen fixation (BNF) of the symbiotic association between peanut (Arachis hypogaea L.) and Bradyrhizobium sp. during a drought-recovery cycle with a focus on the response of enzyme activity and gene expression of the antioxidant system. Peanuts exposed to drought stress had impaired BNF, as indicated by lower nitrogenase activity, and decreased leghaemoglobin content; the latter was reversed to control values upon rehydration. Previous results demonstrated that reactive oxygen species (O2·- and H2O2) were accumulated as a consequence of drought stress, suggesting that nodules experience oxidative stress. In addition, marker transcripts responsive to drought, abscisic acid and H2O2 were upregulated. Increased transcript levels of glutathione reductase were associated with an increased enzyme activity but superoxide dismutase and glutathione S-transferase activities were unchanged, despite upregulated gene transcription. In contrast, increased activity of ascorbate peroxidase (APX) was unrelated with changes in cytosolic APX transcript levels suggesting isogene specificity. In conclusion, the work exemplarily demonstrates the efficient and dynamic regulation of antioxidant enzymes and marker compounds during drought cycling, which is likely to be a prerequisite for functional optimisation of nodule metabolism.
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http://dx.doi.org/10.1071/FP13311DOI Listing
July 2014

Influence of cadmium on the symbiotic interaction established between peanut (Arachis hypogaea L.) and sensitive or tolerant bradyrhizobial strains.

J Environ Manage 2013 Nov 26;130:126-34. Epub 2013 Sep 26.

Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 Km 601, 5800 Río Cuarto, Córdoba, Argentina. Electronic address:

Heavy metals in soil are known to affect rhizobia-legume interaction reducing not only rhizobia viability, but also nitrogen fixation. In this work, we have compared the response of the symbiotic interaction established between the peanut (Arachis hypogaea L.) and a sensitive (Bradyrhizobium sp. SEMIA6144) or a tolerant (Bradyrhizobium sp. NLH25) strain to Cd under exposure to this metal. The addition of 10 μM Cd reduced nodulation and nitrogen content in both symbiotic associations, being the interaction established with the sensitive strain more affected than that with the tolerant one. Plants inoculated with the sensitive strain accumulated more Cd than those inoculated with the tolerant strain. Nodules showed an increase in reactive oxygen species (ROS) production when exposed to Cd. The histological structure of the nodules exposed to Cd revealed a deposit of unknown material on the cortex and a significant reduction in the infection zone diameter in both strains, and a greater number of uninfected cells in those nodules occupied by the sensitive strain. In conclusion, Cd negatively impacts on peanut-bradyrhizobia interaction, irrespective of the tolerance of the strains to this metal. However, the inoculation of peanut with Bradyrhizobium sp. NLH25 results in a better symbiotic interaction suggesting that the tolerance observed in this strain could limit Cd accumulation by the plant.
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http://dx.doi.org/10.1016/j.jenvman.2013.08.056DOI Listing
November 2013

Antioxidant defense system responses and role of nitrate reductase in the redox balance maintenance in Bradyrhizobium japonicum strains exposed to cadmium.

Enzyme Microb Technol 2013 Oct 2;53(5):345-50. Epub 2013 Aug 2.

Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 Km 601, 5800 Río Cuarto, Córdoba, Argentina. Electronic address:

In this work, we evaluated the effects of cadmium (Cd) on the antioxidant defense system responses and the role of nitrate reductase (NR) in the redox balance maintenance in Bradyrhizobium japonicum strains. For that, B. japonicum USDA110 and its NR defective mutant strain (GRPA1) were used. Results showed that the addition of 10μM Cd did not modify the aerobic growth of the wild type strain while the mutant strain was strongly affected. Anaerobic growth revealed that only the parental strain was able to grow under this condition. Cd reduced drastically the NR activity in B. japonicum USDA110 and increased lipid peroxide content in both strains. Cd decreased reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio in B. japonicum USDA110 although, a significant increased was observed in the mutant GRPA1. GSH-related enzymes were induced by Cd, being more evident the increase in the mutant strain. This different behavior observed between strains suggests that NR enzyme plays an important role in the redox balance maintenance in B. japonicum USDA 110 exposed to Cd.
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http://dx.doi.org/10.1016/j.enzmictec.2013.07.007DOI Listing
October 2013
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