Caenorhabditis elegans as a suitable model to evaluate the toxicity of water from Rolante River, southern Brazil.

Urbanization and agricultural activities increased environmental contaminants. Integrated analysis of water parameters and bioassays represents an essential approach to evaluating aquatic resource quality. This study aimed to assess water quality by microbiological and physicochemical parameters as well as the toxicological effects of water samples on the Ames test and Caenorhabditis elegans model. Samples were collected during (collection 1) and after (collection 2) pesticide application in the upper (S1), middle (S2), and lower (S3) sections of the Rolante River, southern Brazil. Metals were determined by GFAAS and pesticides by UPLC-MS/MS. Bioassays using the Ames test and the nematode C. elegans were performed. Levels of microbiological parameters, as well as Mn and Cu were higher than the maximum allowed limits established by legislation in collection 2 compared to collection 1. The presence of pesticide was observed in both collections; higher levels were found in collection 1. No mutagenic effect was detected. Significant inhibition of body length of C. elegans was found in collection 1 at S2 (P < 0.001) and S3 (P < 0.001) and in collection 2 at S2 (P = 0.004). Comparing the same sampling site between collections, a significant difference was found between the site of collection (F(3,6)=8.75, P = 0.01) and the time of collection (F(1,2)=28.61, P = 0.03), for the S2 and S3 samples. C. elegans model was useful for assessing surface water quality/toxicity. Results suggest that an integrated analysis for the surface water status could be beneficial for future approaches.

Bioassays to screen the toxicity in drinking water samples collected in Brazilian rural area.

Agriculture activities have increased the concentration of pesticides and metals in the environment. The excessive use of pesticides can generate an environmental impact and contribute to the development of human diseases. This study aimed to determine the presence of pesticides and metals in water samples collected in the Brazilian rural area in two different periods (before and after pesticide application) and to evaluate the alternative bioassays Lactuca sativa, Allium cepa, and Caenorhabditis elegans to monitoring toxicity in human drinking water samples. Eight sites in the rural area were selected and water samples were collected in two different periods of the year (before and after pesticide application). The presence of the pesticides was determinated by ultra-high performance liquid chromatography-tandem mass spectrometry and metals by inductively coupled plasma mass spectrometry. The potential toxicity of the water samples was performed with three different alternatives in vivo models (L. sativa, A. cepa, and C. elegans). Fifty-seven pesticides were analyzed and, according to the results, the most found ones were clomazone, atrazine, tebuconazole, metconazole, pyrimethanil, and carbofuran-3-hydroxide, which is a metabolic degradation product of insecticide carbofuran. The most detected metals were Cu, Cr, Mg, Fe, and Mn. The assays with L. sativa and A. cepa showed alterations in the period after pesticide application, while C. elegans presented changes in both periods compared to the same collection sites. These results indicate that bioassays, especially C. elegans, could be complementary and useful tools for monitoring the toxicity in drinking water samples.

Zebrafish exposure to diphenyl diselenide-loaded polymeric nanocapsules caused no behavioral impairments and brain oxidative stress.

Previous findings showed that the nanoencapsulation of diphenyl diselenide [(PhSe)2], an organoselenium compound, provided superior biological effects and lower toxicological potential than its free form in vitro. However, few studies reported the behavioral and biochemical effects of this nanocapsules formulation in vivo. Zebrafish (Danio rerio) has emerged as a useful animal model to determine the pharmacological and toxicological effects of nanoparticles. Here, we evaluated the behavioral and brain oxidative effects after zebrafish exposure to (PhSe)2-loaded nanocapsules. Formulations were prepared by interfacial deposition of preformed polymer method and later tested at concentrations ranging from 0.1 to 2.0 µM. Both locomotor and exploratory activities were assessed in the novel tank diving test. Moreover, brain oxidative status was determined by measuring thiobarbituric acid-reactive substance levels, glutathione peroxidase, glutathione redutase and glutathione S-transferase activities. (PhSe)2-loaded nanocapsules showed no alteration on travelled distance, immobility, and erratic swimming, suggesting the absence of behavioral impairments. Interestingly, the higher concentration tested had anxiolytic-like effects, since animals spent more time in the top area and showed a decreased thigmotaxis behavior. Biochemical analysis demonstrated that the concentrations used in this study did not affect oxidative stress-related parameters in brain samples, reinforcing the low toxicological potential of the formulation. In conclusion, the exposure to (PhSe)2-loaded nanocapsules caused no locomotor impairments as well as did not modify the oxidative status of zebrafish brain, indicating that this formulation is probably non-toxic and promising for future pharmacological studies.

The bioaccumulation of waterborne zinc in tissues of silver catfish (Rhamdia quelen) and its effect on biochemical parameters.

Silver catfish (Rhamdia quelen) is a fish species with neotropical distribution, and is a potential model organism to study polluted environment. The aim of this study is to analyze the response of silver catfish to environmental concentrations of waterborne zinc (Zn) over 96 h. Significant metal accumulation was seen in gill, intestine and liver tissues. No significant accumulation was seen in muscle tissue. Lipid peroxidation increased in the brain, and decreased in the muscle and liver at all levels of exposure. Zinc exposure led to decreased protein carbonyl levels in the brain and increased levels in the liver. The activity of catalase in the liver was reduced for all exposed groups. Glutathione S-transferase activity decreased in the brain at the highest level of exposure and in the liver at all Zn concentrations tested. Non-protein thiols increased in the muscle and in the gills after exposure. Ascorbic acid levels increased in the brain and in the gills. Exposure to Zn also altered the metabolic parameters, causing decreased lactate and ammonia levels in the muscle, and decreased glycogen in the liver. Zinc exposure increased ammonia and amino acid levels in the liver, and increase glycogen and amino acid levels in muscle tissue. Our results demonstrate that exposure to environmentally relevant concentrations of Zn led to accumulation of metals in the tissues of silver catfish, with significant changes in biochemical parameters.

Integrated biomarkers response confirm the antioxidant role of diphenyl diselenide against atrazine.

Atrazine (ATZ) is a herbicide worldwide used. That can cause oxidative damage in non-target organisms, such as fish. Furthermore, the threat of exposure to pesticides together with poor nutrition is hazardous to the normal development of fish, and supplementation of the fish diet with antioxidants compounds is an alternative approach to prevent the hazardous effects of pesticide exposure. Here we aimed to investigate the capacity of diphenyl diselenide (PhSe)2 diet supplementation to improve the antioxidant defense of Cyprinus carpio (carp) exposed to environmental concentrations of ATZ. To prove the efficiency of (PhSe)2, we used the Integrated Biomarkers Response (IBR) methodology. Therefore, carp were fed for 8 weeks diets either with or without (PhSe)2 and exposed to 2 or 10µg/L of ATZ for 96h, euthanized, and their liver, gills, and muscle tissues were removed for biochemical assays. ATZ was able to cause oxidative damage from reactive species production in all tissues of carp, as observed by the increase of lipid peroxidation and protein damage. The activity of some antioxidant enzymes was inhibited in carp exposed to ATZ. However, (PhSe)2 supplementation was able to prevent this ATZ-induced damage by improving the activities of antioxidant enzymes and through antioxidant competence of (PhSe)2per se. Furthermore, IBR was shown to be a useful tool to compare treatments, even at different concentrations, and identify the efficiently antioxidant behavior of the organoselenium compound.

Sodium Selenite Prevents Paraquat-Induced Neurotoxicity in Zebrafish.

Considering the antioxidant properties of sodium selenite (Na2SeO3) and the involvement of oxidative stress events in paraquat-induced neurotoxicity, this study investigated the protective effect of dietary Na2SeO3 on biochemical and behavioral parameters of zebrafish exposed to paraquat (PQ). Fish were pretreated with a Na2SeO3 diet for 21 days and then PQ (20 mg/kg) was administered intraperitoneally with six injections for 16 days. In the novel tank test, the Na2SeO3 diet prevented the locomotor impairments, as well as the increase in the time spent in the top area of the tank, and the exacerbation of freezing episodes. In the preference for conspecifics and in the mirror-induced aggression (MIA) tasks, Na2SeO3 prevented the increase in the latency to enter the area closer to conspecifics and the agonistic behavior of PQ-treated animals, respectively. Na2SeO3 prevented the increase of carbonylated protein (CP), reactive oxygen species (ROS), and nitrite/nitrate (NOx) levels, as well as the decrease in non-protein thiols (NPSH) levels. Regarding the antioxidant enzymatic defenses, Na2SeO3 prevented the increase in catalase (CAT) and glutathione peroxidase (GPx) activities caused by PQ. Altogether, dietary Na2SeO3 improves behavioral and biochemical function impaired by PQ treatment in zebrafish, by modulating not only redox parameters, but also anxiety- and aggressive-like phenotypes in zebrafish.

Chronic Treatment with Paraquat Induces Brain Injury, Changes in Antioxidant Defenses System, and Modulates Behavioral Functions in Zebrafish.

Paraquat (PQ) administration consists in a chemical model that mimics phenotypes observed in Parkinson's disease (PD), due to its ability to induce changes in dopaminergic system and oxidative stress. The aim of this study was to evaluate the actions of PQ in behavioral functions of adult zebrafish and its influence on oxidative stress biomarkers in brain samples. PQ (20 mg/kg) was administered intraperitoneally with six injections for 16 days (one injection every 3 days). PQ-treated group showed a significant decrease in the time spent in the bottom section and a shorter latency to enter the top area in the novel tank test. Moreover, PQ-exposed fish showed a significant decrease in the number and duration of risk assessment episodes in the light-dark test, as well as an increase in the agonistic behavior in the mirror-induced aggression (MIA) test. PQ induced brain damage by decreasing mitochondrial viability. Concerning the antioxidant defense system, PQ increased catalase (CAT) and glutathione peroxidase (GPx) activities, as well as the non-protein sulfhydryl content (NPSH), but did not change ROS formation and decreased lipid peroxidation. We demonstrate, for the first time, that PQ induces an increase in aggressive behavior, alters non-motor patterns associated to defensive behaviors, and changes redox parameters in zebrafish brain. Overall, our findings may serve as useful tools to investigate the interaction between behavioral and neurochemical impairments triggered by PQ administration in zebrafish.

Effect of diphenyl diselenide diet supplementation on oxidative stress biomarkers in two species of freshwater fish exposed to the insecticide fipronil.

The ability of diphenyl diselenide [(PhSe)2] to attenuate oxidative damage was evaluated in the liver, gills, brain, and muscle of carp (Cyprinus carpio) and silver catfish (Rhamdia quelen) experimentally exposed to fipronil (FPN). Initially, the fish were fed a diet without (PhSe)2 or a diet containing 3.0 mg/kg of (PhSe)2 for 60 days. After the 60-day period, the fish were exposed to 0.65 µg/L of FPN for 192 h. The results showed that carp exposed to FPN and not fed with (PhSe)2 exhibited acetylcholinesterase (AChE) inhibition in brain and muscle, and increased thiobarbituric acid-reactive substance (TBARS) in liver, gills, and brain. Furthermore, FPN decreased nonprotein thiols (NPSH) and δ-aminolevulinate dehydratase (δ-ALA-D) in carp liver and gills, and increased plasma glucose and protein levels. In silver catfish, FPN inhibited AChE and increased TBARS levels in muscle. In addition, glutathione S-transferase (GST) decreased in liver and muscle, and plasma glucose was increased. (PhSe)2 reversed some of these effects. It prevented the increase in TBARS levels in liver, gills, and brain in carp and in silver catfish muscle, and reversed the increase in plasma glucose levels in both species. Additionally, (PhSe)2 increased the NPSH levels in carp and silver catfish that had decreased in response to FPN exposure. However, (PhSe)2 was not effective in reversing the AChE inhibition in brain and muscle or the δ-ALA-D decrease in carp liver. Thus, (PhSe)2 protects tissues of both species of fish, mainly by preventing or counteracting the effects of FPN, on TBARS levels, antioxidants, and present anti-hyperglycemic property.

Prevalence of anemia in non-severe malaria cases in Mâncio Lima, Acre

Malaria, a parasitic disease, is a serious public health problem. In Brazil, the majority of cases are found in the Amazon. The clinical manifestations of malaria depend on several factors and they may be related to the development of anemia. This study evaluated the prevalence of anemia in malaria cases and its associated factors. The study was conducted in Mâncio Lima (Acre, Brazil). Participants were chosen through passive detection of malaria cases in the municipal health services. They were interviewed and blood samples analyzed for Plasmodium detection and for hemoglobin measurement. SPSS 13.0, software was applied for statistical analysis. One hundred and twenty patients with malaria were studied, of which 58.3% male and 41.7% female. There was a 25% prevalence of anemia, mainly among the women, and in those presenting symptoms for more than four days as well as headaches. The prevalence of anemia and its associated factors in these malaria patients may be connected, not only to the infection, but also to previous or overlapping diseases

Early biochemical biomarkers for zinc in silver catfish (Rhamdia quelen) after acute exposure.

Contamination of aquatic ecosystems by metals causes various biochemical changes in aquatic organisms, and fish are recognized as indicators of environmental quality. Silver catfish were exposed to six concentrations of zinc (Zn): 1.0, 2.5, 5.0, 7.5, 10.0 and 12.5 mg/L for 96 h to determine the mean lethal concentration (LC50). The value obtained was 8.07 mg/L. In a second experiment, fish were exposed to concentrations of 1.0 or 5.0 mg/L Zn and a control for 96 h. Afterward, the tissues were collected for biochemical analysis. Lipid peroxidation, as indicated by thiobarbituric acid-reactive substance (TBARS), decreased in the liver and brain for all Zn concentrations tested, while in the gills TBARS levels increased at 1.0 mg/L and declined at 5.0 mg/L. Zn increased protein carbonyls in the muscle of silver catfish and decreased it in the other tissues. The enzyme superoxide dismutase increased in both exposed groups. However, catalase did not change. Glutathione S-transferase decreased in the liver and increased in the gills (1.0 mg/L), muscle (5.0 mg/L) and brain (1.0 and 5.0 mg/L). Nonprotein thiols changed only in brain and muscle tissue. Zn exposure inhibited acetylcholinesterase (AChE) activity in the brain at both concentrations tested, but did not change it in muscle. Exposure to Zn inhibited the activity of Na(+)/K(+)-ATPase in the gills and intestine at both concentrations tested. Our results demonstrate that Zn alters biochemical parameters in silver catfish and that some parameters such as AChE and Na(+)/K(+)-ATPase could be considered as early biomarkers of waterborne Zn toxicity.

Effects of diphenyl diselenide on growth, oxidative damage, and antioxidant response in silver catfish.

The aim of this study was to evaluate the effects of dietary diphenyl diselenide [(PhSe)2] at different concentrations (1.5, 3.0, and 5.0 mg/kg) on growth, oxidative damage and antioxidant parameters in silver catfish after 30 and 60 days. Fish fed with 5.0 mg/kg of (PhSe)2 experienced a significant decrease in weight, length, and condition factor after 30 days and these parameters increased after 60 days. Thiobarbituric acid reactive substances (TBARS) and protein carbonyl (PC) decreased in the liver of silver catfish supplemented with (PhSe)2 after 30 days at all concentrations, while after 60 days these parameters decreased in liver, gills, brain, and muscle. Supplementation with (PhSe)2 induced a decrease in catalase (CAT) activity from liver only after 60 days of feeding. Superoxide dismutase (SOD) decreased at 5.0 mg/kg after 30 and 60 days and glutathione peroxidase (GPx) was enhanced at 1.5 and 3.0 mg/kg after 30 and 60 days. Silver catfish supplemented for 30 days showed a significant increase in liver glutathione S-transferase (GST) at 3.0 mg/kg, while after 60 days GST activity increased in liver at 1.5, 3.0, and 5.0 mg/kg and in gills at 3.0 and 5.0 mg/kg of (PhSe)2. After 30 days, non-protein thiols (NPSH) did not change, while after 60 days NPSH increased in liver, gills, brain, and muscle. In addition, ascorbic acid (AA) levels after 30 days increased in liver at three concentrations and in gills and muscle at 1.5 mg/kg, while after 60 days, AA increased at all concentrations in all and tissues tested. Thus, diet supplemented with (PhSe)2 for 60 days could be more effective for silver catfish. Although the concentration of 5.0 mg/kg showed decreased growth parameters, concentrations of 1.5 and 3.0 mg/kg, in general, decreased oxidative damage and increased antioxidant defenses.

Exposure to different glyphosate formulations on the oxidative and histological status of Rhamdia quelen.

Due to the wide use of glyphosate (GLY) in soybean cultivation, their residues in the environment may affect non-target organisms such as fish, developing toxic effects. Despite GLY being widely used in Brazil, there are few studies comparing the effects of commercial formulations in native freshwater fish species. Silver catfish (Rhamdia quelen) were exposed to three different commercial formulations of GLY 48% (Orium(®), Original(®) and Biocarb(®)) at 0.0, 2.5 and 5.0 mg/L for 96 h. The effects in thiobarbituric acid-reactive substances (TBARS), catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST) and histological alterations were analysed in the liver, whereas alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were studied in the plasma. In the liver, TBARS levels increased and CAT decreased in all treatments and herbicides tested in comparison with the control group. The SOD increased at 2.5 mg/L of Orium(®), Original(®) and 5.0 mg/L Orium(®) and Biocarb(®), whereas GST increased at 2.5 mg/L Orium(®) and decreased at 2.5 mg/L Biocarb(®) when compared to the control group. The main histopathological alterations in hepatic tissue were vacuolisation, leucocyte infiltration, degeneration of cytoplasm and melanomacrophage in all GLY treatments. The ALT decreased after exposure to 2.5 mg/L of Biocarb(®) and AST increased at 2.5 mg/L of Orium(®), Original(®) and 5.0 mg/L of Biocarb(®) in comparison with the control group. In summary, the oxidative damage generated by GLY may have caused the increased formation of free radicals that led to the histological alterations observed in hepatocytes.

Acute exposure to the biopesticide azadirachtin affects parameters in the gills of common carp (Cyprinus carpio).

The biopesticide, azadirachtin (Aza) is less hazardous to the environment, but may cause several toxic effects in aquatic organisms. The Cyprinus carpio (n=12, for all concentrations) after 10days of acclimation under controlled conditions, were exposed at 20, 40, and 60µL/L of Aza during 96h. After this period, fish were anesthetized and euthanized then mucus layer and gills collected. In this study, the effects of exposure to different Aza concentrations were analysed through a set of biomarkers: Na(+)/K(+-)ATPase, lipid peroxidation (TBARS), protein carbonyl (PC), superoxide dismutase (SOD), glutathione-S-transferase (GST), catalase (CAT), glutathione peroxidase (GPx), non-protein thiols (NPSH), ascorbic acid (AsA) and histological parameters and, yet, protein and glucose concentration in the surface area of mucous layer. Na(+)K(+-)ATPase was inhibited at 40 and 60µL/L compared to control. TBARS decreased at 40µL/L compared to control. PC, SOD and GST increased at 60µL/L in comparison to control. CAT increased at 20 and 60µL/L, and GPx increased in all Aza concentrations compared to control. NPSH decreased and AsA increased in all concentrations in comparison to control. Histological analyses demonstrated an increase in the intensity of the damage with increasing Aza concentration. Alterations in histological examination were elevation and hypertrophy of the epithelial cells of the secondary filament, hypertrophy and hyperplasia of the mucous and chlorate cells and lamellar aneurism. Glucose and protein concentrations in mucus layer increased at 60µL/L compared to control. In general, we suggest that 60µL/L Aza concentration affected several parameters causing disruptions carp metabolism.

Azadirachtin, a neem-derived biopesticide, impairs behavioral and hematological parameters in carp (Cyprinus carpio).

Azadirachtin (Aza) is a promisor biopesticide used in organic production and aquaculture. Although this compound is apparently safe, there is evidence that it may have deleterious effects on fish. Behavioral and hematological tests are grouped into a set of parameters that may predict potential toxicity of chemical compounds. Here, we investigate the effects of Aza, in the commercial formulation Neenmax™ , on carp (Cyprinus carpio) by defining LC50 (96 h), and testing behavioral and hematological parameters. In our study, LC50 was estimated at 80 µL/L. We exposed carp to Aza at 20, 40, and 60 µL/L, values based on 25, 50, and 75% of LC50 , respectively. At 60 µL/L, Aza promoted significant changes in several parameters, increasing the distance traveled and absolute turn angle. In addition, the same concentration decreased the time spent immobile and the number of immobile episodes. Hematological parameters, such as hematocrit, hemoglobin, hematimetrics index, and red cell distribution, were decreased at 60 µL/L Aza exposure. In conclusion, our study demonstrates that 60 µL/L Aza altered locomotor activity, motor pattern, and hematological parameters, suggesting potential toxicity to carp after acute exposure. In addition, this is the first report that evaluates the actions of a chemical contaminant using automated behavioral tracking of carp, which may be a useful tool for assessing the potential toxicity of biopesticides in conjunction with hematological tests. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1381-1388, 2016.

Spatial and temporal biomarkers responses of Astyanax jacuhiensis (Cope, 1894)(Characiformes: Characidae) from the middle rio Uruguai, Brazil

Due to intense agricultural activity in the rio Uruguai (South Brazil), there is the potential for aquatic contamination by agrochemicals. In this region, there are many reservoirs to meet the water demand for rice fields, forming lentic environments. In line with this information, the aim of this study was to show a comparative analysis of some biomarkers, such as lipid peroxidation (TBARS), gluthatione S-transferase (GST), non-protein thiols (NPSH), amino acids (AA) and piscine micronucleus tests (MNE) in Astyanax jacuhiensis from lentic and lotic environments in the middle rio Uruguai region, comparing warm and cold seasons. Eight pesticides were found in water samples, with propoxur having the highest concentration found in both environments and seasons. Fish from the warm season showed higher levels of biochemical biomarkers, and fish from the cold season showed higher levels of MNE and AA. TBARS and AA presented higher levels in fish from the river, while GST, NPSH, MNE and AA presented higher levels in fish from dams. These environments have different characteristics in terms of redox potential, aeration, sedimentation, trophic structure, agrochemicals input and others, which may affect the physiological and biochemical responses of fish in against adverse situations.

Devido à intensa atividade agrícola no rio Uruguai (Sul do Brasil), há potencial para contaminação aquática por agrotóxicos. Há muitos reservatórios para atender a demanda de água de campos de arroz, formando ambientes lênticos. De acordo com estas informações, o objetivo do presente estudo foi mostrar uma análise comparativa de alguns biomarcadores como a peroxidação lipídica (TBARS), glutationa S-transferase (GST), tióis não-protéicos (NPSH), aminoácidos (AA) e teste písceo de micronúcleos (MNE) em Astyanaxjacuhiensis amostrados em ambientes lóticos e lênticos da região do médio rio Uruguai, comparando estações quentes e frias. Oito pesticidas foram encontrados em amostras de água, sendo propoxur a maior concentração encontrada em ambos os ambientes e estações. Peixes da estação quente apresentaram maiores níveis de biomarcadores bioquímicos e peixes da estação fria apresentaram maiores níveis de MNE e AA. TBARS e AA apresentaram maiores níveis nos peixes de rio, enquanto GST, NPSH, MNE e AA apresentaram níveis mais elevados em peixes da represa. Estes ambientes têm características diferentes, com potencial redox, aeração, sedimentação, estrutura trófica, a entrada de agroquímicos e outros que podem afetar as respostas fisiológicas e bioquímicas de peixe contra situação adversa.

Integrated assessment of biomarker response in carp (Cyprinus carpio) and silver catfish (Rhamdia quelen) exposed to clomazone.

Clomazone is considered a potential contaminant of groundwater and is persistent in the environment. To verify the effects of clomazone in Cyprinus carpio and Rhamdia quelen, a method that combines biomarker responses into an index of "integrated biomarker response" (IBR) was used for observed biological alterations in these species. Thiobarbituric acid-reactive substances in liver of carp and silver catfish decreased at both concentrations tested. However, in muscle it increased in carp at 3 mg/L and silver catfish at 6 mg/L. Protein carbonyl increased in liver (3 and 6 mg/L) and muscle (6 mg/L) of carp. In carp, superoxide dismutase (SOD) increased at 3 mg/L and catalase at 6 mg/L. In silver catfish, SOD in liver decreased at 3 mg/L. Glutathione-S-transferase increased at 3 mg/L in muscle of carp. Nonprotein thiol levels decreased at both concentrations in liver of silver catfish and muscle of carp. In silver catfish, acetylcholinesterase (AChE) decreased in brain at 6 mg/L. Nevertheless, AChE in muscle of both species increased at 3 and 6 mg/L. IBR was standardized scores of biomarker responses and was visualized using star plots. The IBR values shown that in carp there was predominantly an induction of parameters, whereas in silver catfish there was inhibition of these responses. In this way, IBR may be a practical tool for the identification of biological alterations in fish exposed to pesticides. In the present study, IBR was efficient for comparisons of fish species using clomazone. This study may serve as a base for evaluation of other pesticides in the rice field, environment, or laboratory experiment.

Glyphosate-based herbicide affects biochemical parameters in Rhamdia quelen (Quoy & Gaimard, 1824 and) Leporinus obtusidens (Valenciennes, 1837)

Rhamdia quelen (silver catfish) and Leporinus obtusidens (piava) were exposed to a commercial formulation Roundup(r), a glyphosate-based herbicide at concentrations of 0.2 or 0.4 mg/L for 96 h. The effects of the herbicide were analyzed on the alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and glucose in plasma, glucose and protein in the mucus layer, nucleotide hydrolysis in the brain, and protein carbonyl in the liver. The parameters were chosen, owing to a lack of information concerning integrated analysis, considering oxidative damage parameters, liver damage, and effects on the mucus layer composition and triphosphate diphosphohydrolase (NTPDase) activities. Plasmatic glucose levels were reduced in both species, whereas the transaminase activities (ALT and AST) increased after exposure to the herbicide. Herbicide exposure increased protein and glucose levels in the mucus layer in both species. There was a reduction in both NTPDase and ecto-5'-nucleotidase activity in the brain of piava, and increased enzyme activity in silver catfish at both concentrations tested. The species showed an increase in protein carbonyl in the liver after exposure to both concentrations of the glyphosate. Our results demonstrated that exposure to Roundup(r) caused liver damage, as evidenced by increased plasma transaminases and liver protein carbonyl in both of the fish species studied. The mucus composition changed and hypoglycemia was detected after Roundup(r) exposure in both species. Brain nucleotide hydrolysis showed a different response for each fish species studied. These parameters indicated some important and potential indicators of glyphosate contamination in aquatic ecosystems.

Rhamdia quelen (jundiá) e Leporinus obtusidens (piava) foram expostos a formulação comercial Roundup(r), um herbicida a base de glifosato nas concentrações de 0,2 e 0,4 mg/L por 96h. Os efeitos do herbicida foram analisados na atividade da alanina aminotransferase (ALT), aspartato aminotransferase (AST) e glicose no plasma, glicose e proteína na camada de muco, hidrólise de nucleotídeos no cérebro e a proteína carbonil no fígado. Os parâmetros foram escolhidos devido à falta de informação com relação a análises integradas, considerando parâmetros oxidativo, danos no fígado, efeitos na composição da camada do muco e atividade da trifosfato difosfoidrolase (NTPDase). Níveis de glicose plasmática foram reduzidos em ambas às espécies, enquanto a atividade das transaminases (ALT e AST) aumentou após exposição ao herbicida. A exposição ao herbicida aumentou a proteína e níveis de glicose na camada de muco em ambas as espécies. Houve uma redução em ambas atividades de NTPDase e ecto-5'-nucleotidase no cérebro de piava, e um aumentou a atividade destas enzimas em jundiás em ambas as concentrações testadas. As espécies mostraram um aumento na proteína carbonil no fígado após exposição a ambas as concentrações de glifosato. Nossos resultados demonstraram que a exposição ao Roundup(r) causou danos no fígado, como evidenciado pelo aumento das transaminases plasmáticas e proteína carbonil no fígado em ambas as espécies de peixes estudadas. A composição do muco alterou e uma hipoglicemia foi detectada após a exposição ao Roundup(r) em ambas espécies. A hidrólise de nucleotídeos em cérebro mostrou diferente resposta para cada espécie estudada. Esses parâmetros indicam alguns importantes e indicadores potenciais da contaminação do glifosato no ecossistema aquático.

How we enhanced medical academics skills and reduced social inequities using an academic teaching program.

The training of future physicians should be concurrent with the development of different skills and attitudes. This warrants the need to regularly provide students with opportunities for self-development throughout their academic career. This approach was exemplified in a medical school in the Brazilian Amazon, where students were allowed to play the role of high school teachers. As part of this exercise, they conducted reinforcement classes for high school students to increase the number of university admissions. The medical students were solely responsible for organizing and implementing this project, giving them the opportunity to develop teaching and leadership skills, enhance their understanding of communication and administration and contribute toward the society.

Commercial formulation containing 2,4-D affects biochemical parameters and morphological indices of silver catfish exposed for 90 days.

The objective of this study was to verify whether a commercial formulation of 2,4 dichlorophenoxyacetic acid [2,4-D dimethylamine salt (DMA)] affects the growth and biochemical parameters of silver catfish (Rhamdia quelen) after 90 days of exposure. The fish exposed to 0.5 or 2.0 mg/L of DMA presented exhibited decreased growth parameters. Glucose was reduced in the mucus layer at both concentrations, and the total protein level was increased at the highest concentration tested. Fish exposed to DMA showed reduced liver and kidney glycogen at both concentrations tested, while in the muscle, glycogen was reduced only at 2.0 mg/L. Glucose was increased in the liver and decreased in the muscle and kidney at both concentrations and was not altered in the plasma. Lactate was increased in all the tissues and decreased in the plasma. Protein levels were reduced in the liver and plasma at both concentrations, while in the muscle, it was decreased at a concentration of 2.0 mg/L. Levels of thiobarbituric acid-reactive substances were reduced in the liver and increased in the muscle at both concentrations and did not change in the brain. DMA increased catalase activity in the liver at both concentrations tested. The present study demonstrates the effects of long-term exposure to DMA. Some parameters could be used as toxicity indicators to identify the presence of DMA in an aquatic environment.

Diet with diphenyl diselenide mitigates quinclorac toxicity in silver catfish (Rhamdia quelen).

In this study, the protective effects of diphenyl diselenide [(PhSe)2] on quinclorac- induced toxicity were investigated in silver catfish (Rhamdia quelen). The fish were fed for 60 days with a diet in the absence or in the presence of 3.0 mg/Kg (PhSe)2. Animals were further exposed to 1 mg/L quinclorac for 8 days. At the end of experimental period, fish were euthanized and biopsies from liver and gills, as well as blood samples, were collected. The cortisol and metabolic parameters were determined in plasma, and those enzyme activities related to osmoregulation were assayed in the gills. In liver, some important enzyme activities of the intermediary metabolism and oxidative stress-related parameters, such as thiobarbituric acid-reactive substance (TBARS), protein carbonyl, catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), nonprotein thiols (NPSH) and ascorbic acid contents were also evaluated. Compared to the control group, quinclorac exposure significantly decreased hepatosomatic index and increased cortisol and lactate values in plasma. Moreover, the activities of fructose biphosphatase (FBPase), glucose-6-phosphate dehydrogenase (G6Pase), glycogen phosphorilase (GPase) and aspartate aminotransferase (AST) were significantly increased in liver. Quinclorac also induced lipid peroxidation while the activity of SOD, NPSH and ascorbic acid levels decreased in the liver. However, dietary (PhSe)2 reduced the herbicide-induced effects on the studied parameters. In conclusion, (PhSe)2 has beneficial properties based on its ability to attenuate toxicity induced by quinclorac by regulating energy metabolism and oxidative stress-related parameters.