Navegando por Autor "Monserrat, Laura Alicia Geracitano"

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Annelids and Nematodes as Sentinels of Environmental Pollution
(2003) Monserrat, José María; Rosa, Carlos Eduardo da; Sandrini, Juliana Zomer; Marins, Luis Fernando Fernandes; Bianchini, Adalto; Monserrat, Laura Alicia Geracitano
Worms like polychaetes, oligochaetes, and nematodes, have been widely used in studies of aquatic and soil pollution. Several ecotoxicological characteristics make these animals suitable for use as a biomonitor, including the fact that these organisms live in close contact with sediments. Also important is that they posses little mobility, which could be useful in biomonitoring programs since it can reflect local environmental problems. Several toxicological aspects are reviewed in these zoological groups, including their antioxidant responses and detoxifying mechanisms of heavy metals. Interestingly, the nematodes and oligochaetes species show induction of proteins different from the well-known metallothionein, including cysteine-rich proteins, and phytochelatins, this last group until recently believed to be present only in plants and fungi.
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Antioxidant Defenses and DNA Damage Induced by UV-A and UV-B Radiation in the Crab Chasmagnathus granulata (Decapoda, Brachyura)
(2005) Gouveia, Glauce Ribeiro; Marques, Daiane; Cruz, Bruno Pinto; Monserrat, Laura Alicia Geracitano; Nery, Luiz Eduardo Maia; Trindade, Gilma Santos
The photoprotector role of pigment dispersion in the melanophores of the crab, Chasmagnathus granulata, against DNA and oxidative damages caused by UV-A and UV-B was investigated.Intact and eyestalkless crabs were used. In eyestalkless crabs,the dorsal epidermis of the cephalothorax (dispersed melanophores)and the epidermis of pereiopods aggregated melanophores)were analyzed. Intact crabs showed only dispersed melanophores in the two epidermis. Antioxidant enzymes activity and lipoperoxidation content were analyzed after UV-A (2.5 J/cm2) or UV-B (8.6 J/cm2) irradiation. DNA damage was analyzed by single cell electrophoresis (comet) assay, after exposure to UV-B (8.6 J/cm2). UV-A radiation increased the glutatione-S-transferase activity in the pereiopods epidermis of eyestalkless crabs (P < 0.05). UV-B radiation induced DNA damage in the dorsal epidermis of eyestalkless crabs (P < 0.05). In pereiopod epidermis of eyestalkless crabs, there was no significant difference between control and UV-B–exposed crabs. In the pereiopods epidermis of eyestalkless, the control group showed higher scores of DNA damage and ~50% of cellular viability. Because in eyestalkless and irradiated crabs the cellular viability was ~5%, it was not possible to observe nuclei for determination of DNA damage. The findings show that melanophores can play a role in the defense against harmful effects of a momentary exposure to UV radiation.
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Antioxidant mechanisms of the nereidid (anelida: polychaeta) to cope with environmental hydrogen peroxide
(2005) Rosa, Carlos Eduardo da; Iurman, Mariana G.; Abreu, Paulo Cesar Oliveira Vergne de; Monserrat, Laura Alicia Geracitano; Monserrat, José María
Hydrogen peroxide (H2O2) is a naturally occurring prooxidant molecule, and its effects in the macroinvertebrate infauna were previously observed. The existence of a gradient of antioxidant enzymes activity (catalase [CAT], glutathione peroxidase [GPx], suéroxide dismutase [SOD], and glutathione-S-transferase [GST] and/or oxidative demage along the body of the estuarine polychaeta Laeonereis acuta (Polychaeta, Nereididae) was analyzed after exposure to H2O2. Because this species secretes conspicuous amounts of mucus, its capability in degrading H2O2 was studied. The results suggest that L. acuta deal with the generation of oxidative stress with different strategies along the body. In the posterior region, higher CAT and SOD activities ensure the degradation of inductors of lipid peroxidation such as H2O2 and superoxide anion (O2.-). The higher GST activity in anterior region aids to conjugate lipid peroxides products. In the middle region, the lack of high CAT, SOD, or GST activities correlates with the higher lipid hydroperoxide levels found after H2O2 exposure. Ten days of exposure to H2O2 also induced oxidative stress (lipid peroxidation and DNA damage) in the whole animal paralleled by a lack of CAT induction. The mucus production contributes substantially to H2O2 degradation, suggesting that bacteria that grow in this secretion provide this capabiblity.
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Antioxidant properties of the mucus secreted by Laeonereis acuta (Polychaeta, Nereididae): a defense against environmental pro-oxidants?
(2006) Moraes, Tarsila Barros; Ferreira, Josencler Luis Ribas; Rosa, Carlos Eduardo da; Sandrini, Juliana Zomer; Votto, Ana Paula de Souza; Trindade, Gilma Santos; Monserrat, Laura Alicia Geracitano; Abreu, Paulo Cesar Oliveira Vergne de; Monserrat, José María
Polychaeta species like Laeonereis acuta (Nereididae) usually secrete great amounts of mucus that wrap the animal inside. Taking into account that fungi action in the sediment and UV radiation acting on dissolved organic matter in the water produces reactive oxygen species (ROS) like hydrogen peroxide (H2O2), it was considered that the mucus secretion could represent an antioxidant defense against environmental ROS. Antioxidant enzymes (catalase—CAT; superoxide dismutase—SOD; glutathione peroxidase—GPx and glutathione-S-transferase—GST) and total antioxidant capacity (TOSC) were determined in worms and mucus secretion. Higher (pb0.05) CAT, GPx and TOSC values were registered in mucus samples respect worms, SOD activity was similar (pN0.05) in both kind of samples, and absence of GST activity was observed in mucus samples, suggesting absence of catalyzed phase II reactions. In assays conducted with hepatoma cell lines exposed to H2O2, it was verified that:(1) mucus co-exposure significantly (pb0.05) lowered DNA damage induced by H2O2; (2) ROS production was significantly (pb0.05) reduced when cells were exposed simultaneously with mucus samples and H2O2 respect H2O2 alone. It can be concluded that the mucus production contributes substantially to the antioxidant defense system of the worm against environmental ROS through the interception or degradation of H2O2, peroxyl and hydroxyl radicals.
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Antioxidant responses and reactive oxygen species generation in different body regions of the estuarine polychaeta Laeonereis acuta (Nereididae)
(2007) Cravo, Marlize Ferreira; Piedras, Fernanda Reinhardt; Moraes, Tarsila Barros; Ferreira, Josencler Luis Ribas; Freitas, Diana Paula Salomão de; Machado, Márcia Dornelles; Monserrat, Laura Alicia Geracitano; Monserrat, José María
The aim of this study was to analyze the total antioxidant capacity (TOSC), generation of reactive oxygen species (ROS) and lipid peroxidation (LPO) in the different body regions of the estuarine polychaeta Laeonereis acuta (Nereididae) sampled at non-polluted (NOPOL)and polluted (POL) sites from Lagoa dos Patos (Southern Brazil). Organisms collected at POL during summer showed similar (p > 0.05)TOSC values along the body, but worms collected at NOPOL presented higher (p < 0.05) TOSC values in the posterior (P) region in respect of anterior (A) region and middle (M) region. TOSC in the P region at NOPOL was higher (p < 0.05) compared with the same body region of worms at POL. In summer, ROS concentration was higher in A andMregions of worms at POL in respect of the organisms at NOPOL. During winter all the regions showed higher ROS in worms sampled at POL. It was registered absence of season influence on LPO content,but in the P region at NOPOL in summer there were lower LPO levels compared with the others regions (p < 0.05). In vitro assays showed that P region, despite a higher basal ROS, presented a higher competence to cope with pro-oxidants compared with A and M regions (p < 0.05), corroborating the field results. A lower proteic sulfhydril content was observed in P in respect of the other regions (p < 0.05) supporting the idea of a highest oxidant condition in this region. The results indicate that worms collected at the POL site are confronted to higher ROS concentrations, affecting its antioxidant capacity, a result that depends of body regions.
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Antioxidant responses in different body regions of the polychaeta Laeonereis acuta (Nereididae) exposed to copper
(2009) Cravo, Marlize Ferreira; Ventura-Lima, Juliane; Sandrini, Juliana Zomer; Amado, Lílian Lund; Monserrat, Laura Alicia Geracitano; Rebelo, Mauro; Bianchini, Adalto; Monserrat, José María
Antioxidant enzymes, total antioxidant capacity (TOSC) and concentration of reactive oxygen species (ROS) were measured in anterior (A), middle (M) and posterior (P) body regions of Laeonereis acuta after copper (Cu; 62.5 mg/l) exposure. A catalase (CAT) activity gradient observed in control group (lowest in A, highest in P) was not observed in Cu exposed group. Glutathione-S-transferase (GST) activity in A region of Cu group was higher than in A region of the control group. DNA damage (comet assay) was augmented in the A region of Cu group. Since copper accumulation was similar in the different body regions, sensitivity to copper in A regions seems to be related to lowest CAT activity. In sum, copper exposure lowered TOSC, a result that at least in part can be related to lowering of antioxidant enzymes like CAT. DNA damage was induced in the anterior region, where a lower CAT activity was observed.
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Application of public-domain statistical analysis software for evaluation and comparison of comet assay data
(2006) Verde, Pablo Emílio; Monserrat, Laura Alicia Geracitano; Amado, Lílian Lund; Rosa, Carlos Eduardo da; Bianchini, Adalto; Monserrat, José María
A novel approach for statistical analysis of comet assay data (i.e.: tail moment) is proposed, employing public-domain statistical software, the R system. The analytical strategy takes into account that the distribution of comet assay data, like the tail moment, is usually skewed and do not follow a normal distribution. Probability distributions used to model comet assay data included: the Weibull, the exponential, the logistic, the normal, the log normal and log-logistic distribution. In this approach it was also considered that heterogeneity observed among experimental units is a random feature of the comet assay data. This statistical model can be characterized with a location parameter mij, a scale parameter r and a between experimental units variability parameter θ. In the logarithmic scale, the parameter mij depends additively on treatment and random effects, as follows: log(mij) = a0 + a1xij + bi, where exp(a0) represents approximately the mean value of the control group, exp(a1) can be interpreted as the relative risk of damage with respect to the control group, xij is an indicator of experimental group and exp(bi) is the individual risk effects assume to follows a Gamma distribution with mean 1 and variance θ. Model selection is based on Akaike’s information criteria (AIC). Real data coming from comet analysis of blood samples taken from the flounder Paralichtys orbignyanus (Teleostei: Paralichtyidae) and from samples of cells suspension obtained from the estuarine polychaeta Laeonereis acuta (Nereididae) were employed. This statistical approach showed that the comet assay data should be analyzed under a modeling framework that take into account the important features of these measurements. Model selection and heterogeneity between experimental units play central points in the analysis of these data.
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Behavioral and neurotoxic effects of arsenic exposure in zebrafish (Danio rerio, Teleostei: Cyprinidae).
(2009) Castro, Micheli Rosa de; Lima, Juliane Ventura; Freitas, Diana Paula Salomão de; Valente, Roberto de Souza; Dummer, Natália Seus; Aguiar, Rosiane Borba de; Santos, Luciane Cougo dos; Marins, Luis Fernando Fernandes; Monserrat, Laura Alicia Geracitano; Monserrat, José María; Barros, Daniela Marti
This study investigated the passive avoidance conditioning in zebrafish (Danio rerio). An instrument was developed for measuring escape responses triggered by a conditioned stimulus. This system allowed quantification of latency of crossing from a light to a dark zone. Zebrafish were trained to swim from an illuminated to a dark compartment, where they received a body shock (training session). The proposed methodology was efficient for evaluation of working, short, and long-term memory formation of an aquatic animal model. The possibility of employing memory measurements in toxicity tests, in order to obtain an ecologically meaningful biomarker response, was also analyzed. In this experiment, immediately after the training session, fish were exposed to three arsenic (AsV) concentrations. After the test session, the brain was removed for biochemical analyses. A control group was kept in tap water. After exposure, animals were submitted to a one-trial inhibitory avoidance test for measurement of long-term memory (LTM). Results from behavioral and biochemical analyses showed that the three AsV concentrations impaired LTM (pb0.05) and increased protein oxidation, which suggests an amnesic and pro-oxidant effect of AsV. Evaluation of behavior parameters in aquatic models is an important complement in studies concerning the environmental impact of chemical substances.
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Behavioral and neurotoxic effects of arsenic exposure in zebrafish (Danio rerio,Teleostei: Cyprinidae)
(2009) Castro, Micheli Rosa de; Lima, Juliane Ventura; Freitas, Diana Paula Salomão de; Valente, Roberto de Souza; Dummer, Natália Seus; Aguiar, Rosiane Borba de; Santos, Luciane Cougo dos; Marins, Luis Fernando Fernandes; Monserrat, Laura Alicia Geracitano; Monserrat, José María; Barros, Daniela Marti
This study investigated the passive avoidance conditioning in zebrafish (Danio rerio). An instrument was developed for measuring escape responses triggered by a conditioned stimulus. This system allowed quantification of latency of crossing from a light to a dark zone. Zebrafish were trained to swim from an illuminated to a dark compartment,where they received a body shock (training session). The proposed methodology was efficient for evaluation of working, short, and long-term memory formation of an aquatic animal model. The possibility of employing memory measurements in toxicity tests, in order to obtain an ecologically meaningful biomarker response, was also analyzed. In this experiment, immediately after the training session, fish were exposed to three arsenic (AsV) concentrations. After the test session,the brain was removed for biochemical analyses. A control group was kept in tap water. After exposure, animals were submitted to a one-trial inhibitory avoidance test for measurement of long-term memory (LTM). Results from behavioral and biochemical analyses showed that the three AsV concentrations impaired LTM (pb0.05) and increased protein oxidation, which suggests an amnesic and pro-oxidant effect of AsV. Evaluation of behavior parameters in aquatic models is an important complement in studies concerning the environmental impact of chemical substances.
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Biomarkers in croakers Micropogonias furnieri (Teleostei: Sciaenidae) from polluted and non-polluted areas from the Patos Lagoon estuary (Southern Brazil): Evidences of genotoxic and immunological effects
(2006) Amado, Lílian Lund; Rosa, Carlos Eduardo da; Leite, Alice Teixeira Meirelles; Moraes, Loraine; Pires, Wagner Vaz; Pinho, Grasiela Lopes Leães; Martins, Camila De Martinez Gaspar; Robaldo, Ricardo Berteaux; Nery, Luiz Eduardo Maia; Monserrat, José María; Bianchini, Adalto; Martínez, Pablo Elías; Monserrat, Laura Alicia Geracitano
Biomarkers of exposure and effect of pollutants were analyzed in croakers Micropogonias furnieri (Teleostei: Sciaenidae) captured in winter and summer in a polluted and in a non-polluted site at the Patos Lagoon estuary (Southern Brazil). Catalase and glutathione Stransferase activities (exposure biomarkers) and lipid peroxidation (effect biomarker) were analyzed in liver samples. Other two effect biomarkers were also studied: blood cells DNA damage (through comet assay and micronucleus test) and respiratory burst measurements. In a broad view, results point to an important seasonal variation of the biochemical biomarkers analyzed. However, data obtained clearly indicate that croakers collected in winter at the polluted site were subjected to a level of clastogenic agents sufficient to generate irreversible genetic damages (mutations) and impair the fish immune system.
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Biomarkers of exposure and effect in the Brazilian flounder Paralichthys orbignyanus (Teleostei: Paralichthyidae) from the Patos Lagoon estuary (Southern Brazil).
(2006) Amado, Lílian Lund; Robaldo, Ricardo Berteaux; Monserrat, Laura Alicia Geracitano; Monserrat, José María; Bianchini, Adalto
Biomarkers of exposure (liver metallothionein-like proteins content and catalase and glutathione S-transferase activities) and effect (liver lipoperoxidation and blood cell DNA damage) of contaminants were analyzed in the Brazilian flounder Paralichthys orbignyanus from the Patos Lagoon estuary (Southern Brazil). Flounders were collected for a year in two sites: ‘‘Coroa do Boi’’ (polluted site) and ‘‘Saco do Justino’’ (non-polluted site). Results indicated that micronucleated cells frequency was the best biomarker to distinguish flounders from the two sites. Taken together, data from DNA damage analyses (micronucleus test and comet assay) indicated that flounders from the non-polluted site efficiently repaired the DNA breaks, contrary to those from the polluted site, which probably had their DNA repair system inhibited or exhausted. Furthermore, data from enzyme activities (catalase and GST) and lipid peroxidation indicated that flounders from the polluted site were under oxidative stress in summer and autumn.
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Contribution of microorganisms to the biofilm nutritional quality: protein and lipids contents
(2008) Silva, Caroline Fernandes da; Ballester, Eduardo Luis Cupertino; Monserrat, José María; Monserrat, Laura Alicia Geracitano; Wasielesky Junior, Wilson Francisco Britto; Abreu, Paulo Cesar Oliveira Vergne de
The nutritional quality of biofilm, a microbial community associated to an organic matrix, was evaluated in artificial substrate (polyethylene screen) in net cages during 30 days in the Patos Lagoon estuary, Southern Brazil. During this period, samples of biofilm were collected each 5 days for analysis of chlorophyll a, microorganisms abundance, dry weight, protein and lipid contents. During the study, chlorophyll a varied from 0.38 to 2.75 lg cm)2; dry weight between 7.16 and 17.63 mg cm)2; protein content from 0.43 to 1.76 mg cm)2 and lipid concentration between 1.21 and 4.23 mg cm)2. The variation of lipid in the biofilm was closely related to the abundance of free heterotrophic bacteria (34.25–56.54 · 106 cells cm)2), filamentous cyanobacteria (7.5–15.9 · 106 filaments cm)2), flagellates (6.92–12.89 · 106 cells cm)2) and mainly nematodes (29–1,414 organisms cm)2), while protein content varied similarly to the abundance of unicellular centric diatoms (52.10–179.81 · 103 cells cm)2), and nematodes. This information will allow a better management of food supply to raised aquatic organism with the utilization of natural productivity in the culture systems, with considerable decrease decrease in production costs.
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Current and Future Perspectives Using Biomarkers to Assess Pollution in Aquatic Ecosystems
(2003) Monserrat, José María; Monserrat, Laura Alicia Geracitano; Bianchini, Adalto
The possibility of detecting aquatic pollution problems to take corrective decisions is intimately related to the organization levels of the living matter. Measurements at the biochemical or physiological levels detect more quickly and specifically the presence of several toxic compounds, allowing its utilization in a prospective way, until that deleterious effect reaches higher organization levels. The detection of environmental ‘‘hot spots’’ needs general nonspecific biomarkers if no previous information about the presence of specific pollutants exist. Since several xenobiotics can modify directly or indirectly the balance between pro-oxidant and antioxidant concentration, the determination of oxidative stress (DNA damage, protein oxidation, lipid peroxidation) in aquatic species is commonly used as a nonspecific biomarker. On the other hand, acetylcholinesterase activity or determination of metallothionein concentration (or expression) represents specific biomarkers that indicate the presence of anticholinesterasic compounds (organophosphorus pesticides or neurotoxins, for instance) and metals, respectively. The fact that animal populations inhabiting polluted areas can express responses qualitatively and quantitatively different from those of reference areas has lead to the ‘‘pollution induced community tolerance’’ approach that seems to be a valuable tool to compare toxicological responses of different aquatic populations.
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Determination of Lipid Peroxides in Invertebrates Tissues Using the Fe(III) Xylenol Orange Complex Formation
(2003) Monserrat, José María; Monserrat, Laura Alicia Geracitano; Pinho, Grasiela Lopes Leães; Vinagre, Tânia Mariza de Mattos; Faleiros, Markel; Alciati, Julieta Carvalho; Bianchini, Adalto
Reactive oxygen species (ROS) are subproducts of the oxidative metabolism known to initiate chain reactions with polyunsaturated fatty acids that generate lipid peroxides (LPO). The objective of this work was to adapt the ferrous oxidation/xylenol orange (FOX) assay to measure LPO in invertebrate tissues i.e.: from polychaeta (Laeonereis acuta) and crab (Chasmagnathus granulata) species. Whole polychaetes were homogenized in methanol 100%, being determined the optimal sample volume and the time required for color development. It was tested five sample volumes (8 –30 _l), following color development up to 215 min. Absorbance stabilization was observed after 90 min, being linearly related with sample volume. A similar procedure was adopted for crab tissues (anterior gills, posterior gills, and hepatopancreas). Differences between species and between organs of the same species were observed when analyzed nonspecific absorbance increments after adding the standard cumene hydroperoxide (CHP). In polychaeta and crab anterior gills tissue, absorbance increments were lower (21–25%) than samples without tissue extracts (blanks) that received CHP. In crab posterior gills and hepatopancreas, the nonspecific increment was almost negligible. Correction formulae are given to account for these differences and simplified protocols for each tissue and species are also included. Great differences in the lipid peroxides content was detected between worms (127.05 _ 19.32 nmoles CHP/g of wet tissue) respect to anterior gills, posterior gills, and hepatopancreas from the crab species (52.65 _ 3.59, 30.54 _ 4.73, and 48.51 _ 8.78 nmoles CHP/g of wet tissue, respectively).
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Effects of arsenic (As) exposure on the antioxidant status of gills of the zebrafish Danio rerio (Cyprinidae)
(2009) Ventura-Lima, Juliane; Castro, Micheli Rosa de; Acosta, Daiane da Silva; Fattorini, Daniele; Regoli, Francesco; Carvalho, Leandro Machado de; Bohrer, Denise; Monserrat, Laura Alicia Geracitano; Barros, Daniela Marti; Marins, Luis Fernando Fernandes; Silva, Rosane Souza da; Bonan, Carla Denise; Bogo, Maurício Reis; Monserrat, José María
In fishes, arsenic (As) is absorbed via the gills and is capable of causing disturbance to the antioxidant system. The objective of present studywas to evaluate antioxidant responses after As exposure in gills of zebrafish(Danio rerio, Cyprinidae). Fish were exposed for 48 h to three concentration of As, including the highest As concentration allowed by current Brazilian legislation (10 μg As/L). A control group was exposed to tap water (pH 8.0; 26 °C; 7.20 mg O2/L). As exposure resulted in (1) an increase (pb0.05) of glutathione (GSH) levels after exposure to 10 and 100 μg As/L, (2) an increase of the glutamate cysteine ligase (GCL) activity in the same concentrations (pb0.05), (3) no significant differences in terms of glutathione reductase, glutathione-Stransferase and catalase activities; (4) a significantly lower (pb0.05) oxygen consumption after exposure to 100 μg As/L; (4) no differences in terms of oxygen reactive species generation and lipid peroxidation content(pN0,05). In the gills, only inorganic As was detected. Overall, it can be concluded that As affected the antioxidant responses increasing GCL activity and GSH levels, even at concentration considered safe by Brazilian legislation.
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Effects of microcystins over short- and long-term memory and oxidative stress generation in hippocampus of rats
(2006) Maidana, Michelle; Carlis, Vania; Galhardi, Flora Gagliardi; Yunes, João Sarkis; Monserrat, Laura Alicia Geracitano; Monserrat, José María; Barros, Daniela Marti
Microcystins produced by cyanobacteria are potent inhibitors of some protein phosphatases, but recent evidence also indicatests potential to generate oxidative stress. In the present study, the effects of microcystin raw extracts (Mic; 0.01 and 20 g/L) and purified okadaic acid(OA; 0.01 and 10 g/L) on short- and long-term memory alteration and antioxidant and oxidative damage were investigated in hippocampus of rats. The results showed an amnesic effect with 0.01 and 20 g/L Mic on retrieval and only with 0.01 g/L Mic on spatial learning. Parallel to these effects oxidative damage was observed as evidenced by augmented levels of lipid peroxides and DNA damage and the absence of antioxidant responses in terms of total oxyradical scavenging capacity. Phase II reactions catalyzed by glutathione-S-transferase were not modified after microcystins exposure. Overall this study showed physiological events (retrieval and spatial learning) that can be related to the classical toxic effects of microcystins (i.e., phosphatase inhibition). In addition, evidence of alternative toxicity mechanisms via oxidative stress generation was also obtained. The fact that organic anion transporter polypeptides (OATP) involved in microcystins uptake are expressed not only in liver but also in brain points to the environmental relevance of the observed effects.
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Gorduras trans nas revistas de divulgação, livros didáticos e rótulos de produtos alimentícios
(2010) Borges, Elizandra Luçardo; Monserrat, Laura Alicia Geracitano
Com base nos inúmeros estudos que vêm sendo realizados, os pesquisadores estão estabelecendo relação direta entre o consumo de gorduras-trans e os altos índices de doenças cardiovasculares, com isso percebemos a importância da repercussão desse tema nos diversos artefatos culturais. Assim, esta dissertação tem como objetivo investigar as revistas de divulgação, os livros didáticos e os rótulos de produtos alimentícios a fim de verificar os significados que tais artefatos vêm produzindo no que diz respeito às gordurastrans e o quanto eles produzem discursos com relação à alimentação e a saúde dos sujeitos. Este estudo fundamenta-se a partir do campo teórico dos Estudos culturais sob um viés pós- estruturalista, entendendo que as pedagogias que permeiam tais artefatos produzem os modos de ser e viver dos sujeitos, mostrando o quanto essas pedagogias modificam e instituem as identidades e as subjetividades. Percebemos que os conhecimentos apresentados pelos artefatos são produzidos em instituições autorizadas como universidades, institutos e agências, mas nem todos os conhecimentos são considerados válidos para compor os currículos desses artefatos estabelecendo algumas relações de poder na escolha dos temas que emergem dependendo da demanda econômica sóciocultural. Assim vamos entender que os enunciados que são apresentados pelas revistas, livros didáticos e rótulos de produtos alimentícios atrelados ao discurso da ciência regula, dita e prescreve os cuidados que os sujeitos devem ter com relação á alimentação e a saúde.
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Histological and morphological alterations induced by copper exposure in Laeonereis acuta (Polychaeta, Nereididae)
(2004) Monserrat, Laura Alicia Geracitano; Monserrat, José María; Bianchini, Adalto; Luquet, Carlos Marcelo
Laeonereis acuta (Polychaeta, Nereididae) was collected in an unpolluted (UP) and an polluted (P) site at the Patos Lagoon estuary (Southern Brazil) and maintained under control conditions (UPC and PC, respectively) or exposed to waterborne copper (UPCu and PCu; 500 lg Cu/l), for 48 h. Four groups (aaUPC, aaPC, aaUPCu, and aaPCu) were also pre-exposed for 48 h to ascorbic acid (aa; 0.1 mM) before copper exposure. Histological and morphological alterations, as well as oxygen consumption changes were evaluated. Independently of the sampling site and the pre-exposure to the ascorbic acid, morphological abnormalities were evident in more than 80% of worms exposed to copper. Conspicuous histological changes (coeloma obliteration, cuticle separation from the epidermis, and absence of dorsal vessel) were also observed. In addition, PCu worms showed loss of the digestive epithelium and coiling behavior. Similar oxygen consumption values were observed in control and copper exposed worms.
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In vitro exposure to fullerene C60 influences redox state and lipid peroxidation in brain and gills from Cyprinus carpio (Cyprinidae)
(2012) Ferreira, Josencler Luis Ribas; Barros, Daniela Marti; Fossa, Carlos Eduardo; Monserrat, Laura Alicia Geracitano; Fillmann, Gilberto; Almeida, Eduardo Alves de; Prado, Mariana de Castro; Neves, Bernardo Ruegger Almeida; Pinheiro, Maurício Veloso Brant; Monserrat, José María
Studies concerning the impact of nanomaterials, especially fullerene (C60), in fresh water environments and their effects on the physiology of aquatic organisms are still scarce and conflicting. We aimed to assess in vitro effects of fullerene in brain and gill homogenates of carp Cyprinus carpio, evaluating redox parameters. A fullerene suspension was prepared by continued stirring under fluorescent light during two months. The suspension concentration was measured by total carbon content and ultraviolet–visible spectroscopy nephelometry. Characterization of C60 aggregates was performed with an enhanced dark-field microscopy system and transmission electronic microscopy. Organ homogenates were exposed during 1, 2, and 4 h under fluorescent light. Redox parameters evaluated were reduced glutathione and oxidized glutathione, cysteine and cystine, total antioxidant capacity; activity of the antioxidant enzymes glutathioneS-transferase and glutathione reductase (GR), and lipid peroxidation (TBARS assay). Fullerene induced a significant increase (p < 0.05) in lipid peroxidation after 2 h in both organs and reduced GR activity after 1 h (gills) and 4 h (brain) and antioxidant capacity after 4 h (brain). Levels of oxidized glutathione increased in the brain at 1 h and decreased at 2 h as well. Given these results, it can be concluded that C60 can induce redox disruption via thiol/disulfide pathway, leading to oxidative damage (higher TBARS values) and loss of antioxidant competence. Environ. Toxicol. Chem. 2012; 31: 961–967. © 2012 SETAC
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In vitro exposure to fullerene c60 influences redox state and lipid peroxidation in brain and gills from cyprinus carpio (cyprinidae)
(2012) Ferreira, Josencler Luis Ribas; Barros, Daniela Marti; Monserrat, Laura Alicia Geracitano; Fillmann, Gilberto; Fossa, Carlos Eduardo; Almeida, Eduardo Alves de; Prado, Mariana de Castro; Neves, Bernardo Ruegger Almeida; Pinheiro, Maurício Veloso Brant; Monserrat, José María
Studies concerning the impact of nanomaterials, especially fullerene (C60), in fresh water environments and their effects on the physiology of aquatic organisms are still scarce and conflicting. We aimed to assess in vitro effects of fullerene in brain and gill homogenates of carp Cyprinus carpio, evaluating redox parameters. A fullerene suspension was prepared by continued stirring under fluorescent light during two months. The suspension concentration was measured by total carbon content and ultraviolet–visible spectroscopy nephelometry. Characterization of C60 aggregates was performed with an enhanced dark-field microscopy system and transmission electronic microscopy. Organ homogenates were exposed during 1, 2, and 4 h under fluorescent light. Redox parameters evaluated were reduced glutathione and oxidized glutathione, cysteine and cystine, total antioxidant capacity; activity of the antioxidant enzymes glutathione S-transferase and glutathione reductase (GR), and lipid peroxidation (TBARS assay). Fullerene induced a significant increase ( p<0.05) in lipid peroxidation after 2 h in both organs and reduced GR activity after 1 h (gills) and 4 h (brain) and antioxidant capacity after 4 h (brain). Levels of oxidized glutathione increased in the brain at 1 h and decreased at 2 h as well. Given these results, it can be concluded that C60 can induce redox disruption via thiol/disulfide pathway, leading to oxidative damage (higher TBARS values) and loss of antioxidant competence.