Oxidative balance in brain after chronic exposure to arsenic

The effect of chronic As exposure in brain, the specific oxidantsproduction and oxidative stress still needs more attention. In the presentstudy, male wistar rats were chronically exposed to As bythe drinkingwater during 60 days. The rats receiving a dose of 10 mg As/l showed a9- and 18-fold increase in the content of As in blood and brain,respectively, as compared to the control group. Histopathologicalchanges were detected in brain samples isolated from animals treatedwith Asas compared to control animals. The oxidation rate of 2ʹ,7ʹ-Dichlorofluorescein diacetate (DCFH-DA) showed no significantchanges after the treatment. A significant increase (13%) in the steadystate concentration of ascorbyl radical (A?) was determined in the brainisolated from animals exposed to 50 mg As/l. The lipid radical (LR?)generation rate and the content of malondialdehyde (MDA) wereincreased by 34% and 32%, respectively in brain isolated from ratsreceiving 50 mg As/l. The content of ascorbate (AH-) in brain was notaffected by the exposure to As.However, the content of glutathione(GSH) and the lipophilic antioxidant α-tocopherol (α-T), weresignificantly decreased after As supplementation, as compared tocontrol brains. The A?/AH- content ratio in rat brain showed no changesassociated to the As supplementation. Nevertheless, a significantincrease of 44% and 55% was determined in the LR?/α-T and MDA/α-Tcontent ratios, respectively, suggesting that the oxidative imbalance inthe lipophilic cellular medium could be the primarily effect of Asassociated to membrane damage.Fil: Bonetto, Julián Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Puntarulo, Susana Ángela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentin

Oxidative metabolism of photosynthetic species and the exposure to some freshwater and marine biotoxins

Environmental climate conditions could lead to an increasing global occurrence of microorganism blooms that synthesize toxins in the aquatic environments. These blooms could result in significantly toxic events. Responses of photosynthetic organisms to adverse environmental conditions implicate reactive oxygen species generation; but, due to the presence of a varied cellular antioxidant defense system and complex signaling networks, this oxidative stress could act as an important factor in the environmental adaptive processes. The objective of this review was to assess how some biotoxins are implicated in the generation of oxidative and nitrosative metabolic changes, not only in biotoxin-producing organisms but also in non-producing organisms. Therefore, toxins may modify the oxidative cellular balance of several other species. Hence, the effect of toxins on the oxidative and nitrosative conditions will be evaluated in freshwater and marine algae and vascular plants. The changing climate conditions could act as agents capable of modifying the community composition leading to alterations in the global health of the habitat, risking the survival of many species with ecological relevance.Fil: Puntarulo, Susana Ángela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: González, Paula Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin

The Phycotoxin Domoic Acid as a Potential Factor for Oxidative Alterations Enhanced by Climate Change

Harmful algal blooms (HAB) threaten aquatic and marine ecosystems and wildlife through the creation of hypoxic conditions, and through the toxins they produce. Climate change is creating conditions that increase the impact of HAB on the aquatic ecosystems, rising the frequency of these events. Domoic acid (DA) is a marine phycotoxin produced during HAB of the diatoms Pseudonitzchia sp. It was described that DA causes production of reactive oxygen species (ROS), neurological dysfunction, DNA damage, lipid peroxidation, energy depletion, mitochondrial damage and cell death in animals and humans. However, the information about the effect of this phycotoxin on the non-toxin producing phytoplankton community is scarce or null in relation to oxidative stress measurements. The hypothesis of this opinion article is that DA produced by HAB, might favor the generation of reactive species, that through diffusion to the extracellular environment modifies the oxidative metabolism of non-toxin-producing marine phytoplankton. This feature opens the possibility that not only the phytoplankton community, but also the rest of the food web might be deeply affected if, due to global warming, HAB magnitude and frequency continue increasing.Fil: Cabrera, Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: González, Paula Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Puntarulo, Susana Ángela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentin

Fe-Allocation in Liver during Early Stages of Endotoxemia in Fe Overload Rats

The hypothesis of this study was that alterations in Fe distribution triggered by lipopolysaccharide (LPS) administration were affected in vivo by Fe overload. Lipopolysaccharide treatment by itself significantly decreased Fe content in serum and increased the blood NO-hemoglobin (NO-Hb) EPR signal and nitrotyrosine protein content in liver, as compared to values in control animals. Fe overload (produced by Fe-dextran ip administration) caused an increase, as compared to values in control animals, in Fe content in serum, and a significant enhancement in ferritin (Ft) content, Fe content in Ft, the labile Fe pool (LIP), and the protein carbonyl content in the liver. The simultaneous administration of LPS and Fe-dextran lead to a significant increase in the Fe content in serum, blood NO-Hb EPR signal, the content of Fe, Fe in Ft, LIP, protein carbonyl, and nitrotyrosine protein in liver, as compared to values in control animals. The data reported here indicate that the protective strategy against endotoxemia of sequestering serum Fe content is not fully operative under Fe overload conditions. However, the oxidative condition of the liver does not seem to be being affected, since endogenous mechanisms were able to regulate the amount of catalytically active Fe to the same levels observed after Fe-dextran administration, even in the presence of LPS, over the initial six-hour period.Fil: Rousseau, Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Programa de Radicales Libres; ArgentinaFil: Galleano, Mónica Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Puntarulo, Susana Ángela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentin

Acute Fe-dextran treatment and redox balance in rat whole brain and cortex

An acute Fe-dextran treatment produced oxidative stress in rat brain that lead to the translocation of Nrf2 to the cell nucleus, producing the activation of genes involved in the glutathione metabolism in the cellular environment. Previous reports have shown that the acute Fe overload produced by a single injection of Fe-dextran resulted in a significant decrease in total thiol and glutathione content in rat cortex area after 6 and 8 h post injection (pi). In the whole brain, enzymatic activities of glutathione-S-transferase (GST) and glutathione peroxidase (GPx), and total thiol content were increased as compared to control tissues at 6 or 8 h pi, respectively. The aim of this study was to determine the effect of acute Fe overload on glutathione-dependent enzymatic metabolism in cortex rat brain. A single dose of 500 mg Fe-dextran/kg body weight was administrated intraperitoneally to male Sprague Dawley rats. Total brain samples or cortex area were obtained from control and treated animals after 6 or 8 h pi. Glutathione reductase (GR) was determined spectrophotometrically. Reduced glutathione (GSH), oxidized glutathione (GSSG) and malondialdehyde (MDA) content were determined by reverse phase HPLC. MDA content showed a significant increased (p<0.05) at 8 h pi in whole brain. A significant decrease in cortical GSH (p<0.05), and a significant increase in cortical GSSG (p<0.05) was observed at 8 h pi. A slight but non-significant reduction in the activity of the enzyme GR was seen at 6 and 8 h pi in brain cortex. Taking as a whole, these results suggested that the increase in the GSSG/GSH ratio could be associated to the increase in the activities of GST and GPx without any change in GR activity in brain cortex. Moreover, it seems that the alteration in the redox status caused by the Fe treatment in the cortex could contribute to the lipid peroxidation changes detected in the whole brain.Fil: Piloni, Natacha Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Robello, Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Puntarulo, Susana Ángela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaLXIV Reunión Anual de la Sociedad Argentina de Investigación Clínica; LI Reunión Anual de la Asociación Argentina de Farmacología Experimental; XXI Reunión Anual de la Sociedad Argentina de Biología; XXXI Reunión Anual de la Sociedad Argentina de Protozoología; IX Reunión Anual de la Asociación Argentina de Nanomedicinas y VI Reunión Científica Regional de la Asociación Argentina de Ciencia y Tecnología de Animales de LaboratorioMar del PlataArgentinaSociedad Argentina de Investigación ClínicaAsociación Argentina de Farmacología ExperimentalSociedad Argentina de BiologíaSociedad Argentina de ProtozoologíaAsociación Argentina de NanomedicinasAsociación Argentina de Ciencia y Tecnología de Animales de Laboratori

An update on the effects of glyphosate on the oxidative state in biological systems

El glifosato es un herbicida de amplio espectro que se utiliza para el control de malezas en cultivos de interés agrícola; genera la muerte del organismo blanco afectando su capacidad de sintetizar proteínas esenciales para la supervivencia. El glifosato inhibe la enzima 5-enolpiruvilshikimato3-fosfato sintasa que forma parte de la vía metabólica de producción de aminoácidos aromáticos, ya que se comporta como un análogo de un sustrato de dicha enzima. Se han presentado evidencias que indican que el glifosato y sus formulaciones comerciales generan situaciones de estrés oxidativo en cianobacterias, microalgas y plantas superiores no blanco de este herbicida. Sin embargo, la verdadera dimensión de la magnitud del efecto oxidativo generado por la exposición al herbicida, aún es materia de deliberación. El objetivo del presente trabajo es resumir la información disponible sobre el metabolismo y la participación del estrés oxidativo en la toxicidad del glifosato en sistemas biológicos. El conocimiento de los riesgos ambientales generados por el uso del glifosato ayudará a evitar daños irrecuperables tanto en plantas como en animales al emplear el herbicida.Glyphosate is a broad-spectrum herbicide used for weed control in crops of agricultural interest. This herbicide causes the death of the target by afecting their ability to synthesize proteins essential for survival. The activity of the 5-enolpiruvilshikimato-3-phosphate synthase enzyme, which is part of the metabolic pathway for production of aromatic amino acids, is inhibited by the glyphosate that behaves as an analogue of the second substrate (phosphoenolpyruvate). There is evidence that indicate glyphosate (and its formulations) produce oxidative stress in cyanobacteria, microalgae and no-target higher plants. However, the true dimension of the magnitude of the oxidative efect generated by the exposure is still a matter of discussion. The objective of the present study is to summarize the available information on the metabolism and the involvement of oxidative stress in the toxicity of glyphosate on biological systems. Increasing the awareness of the environmental risks generated by the use of glyphosate will help to avoid unrecoverable damage to both, plants and animals during herbicide handling.Fil: Ostera, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Malanga, Gabriela Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Puntarulo, Susana Ángela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin

Oxidative effects of the harmful algal blooms on primary organisms of the food web

Degraded water quality from nutrient pollution, physical, biological, and other chemical factors contributes to the development and persistence of many harmful algal blooms (HABs). The complex dynamics of the HABs is a challenge to marine ecosystems for the toxic effects reported. The consequences include fish, bird, and mammal mortality, respiratory or digestive tract problems, memory loss, seizures, lesions and skin irritation in many organisms. This review is intended to briefly summarize the recent reported information on harmful marine toxin deleterious effects over the primary organisms of the food web, namely algae, zooplankton and invertebrates. Special focus is made on oxidative stress status of cells and tissues. Even though in situ field research is less controlled than laboratory studies, in which the organisms are directly exposed to the toxins under consideration, both types of approaches are required to fully understand such a complex scenario. On top of that, the contribution of the increasing water temperatures in thesea, as a consequence of the global climate change, will be addressed as a topic for further studies, to evaluate the effect on regulating algal growth, species composition, trophic structure, metabolic stress and function of aquatic ecosystems.Fil: Cabrera, Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: González, Paula Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Puntarulo, Susana Ángela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentin

Chloroplasts as a nitric oxide cellular source : Effect of reactive nitrogen species on chloroplastic lipids and proteins

Nitric oxide (NO) generation by soybean (Glycine max var. ADM 4800) chloroplasts was studied as an endogenous product assessed by the electron paramagnetic resonance spin-trapping technique. Nitrite and L-arginine (Arg) are substrates for enzymatic activities considered to be the possible sources of NO in plants. Soybean chloroplasts showed a NO production of 3.2 ± 0.2 nmol min-1 mg-1 protein in the presence of 1 mM NaNO 2. Inhibition of photosynthetic electron flow by 3-(3,4- dichlorophenyl)-1,1-dimethyl urea resulted in a lower rate (1.21 ± 0.04 nmol min-1 mg-1 protein) of NO generation. Chloroplasts incubated with 1 mM Arg showed NO production of 0.76 ± 0.04 nmol min -1 mg-1 protein that was not affected either by omission of Ca2+ or by supplementation with Ca2+ and calmodulin to the incubation medium. This production was inhibited when chloroplasts were incubated in the presence of NO synthase inhibitors Nω,-nitro- L-Arg methyl ester hydrochloride and Nω-nitro-L-Arg. In vitro exposure of chloroplasts to an NO donor (250 μM S-nitrosoglutathione) decreased lipid radical content in membranes by 29%; however, incubation in the presence of 25 μM peroxynitrite (ONOO-) led to an increase in lipid-derived radicals (34%). The effect of ONOO- on protein oxidation was determined by western blotting, showing an increase in carbonyl content either in stroma or thylakoid proteins as compared to controls. Moreover, ONOO- treatment significantly affected both O2 evolution and chlorophyll fluorescence in thylakoids. Data reported here suggest that NO is an endogenous metabolite in soybean chloroplasts and that reactive nitrogen species could exert either antioxidant or prooxidant effects on chloroplast macromolecules.Instituto de Fisiología Vegeta