Biochemical changes and bioaccumulation of manganese in Astyanax lacustris (Teleostei: Characidae).

Major tailings dam failures have occurred recently around the world and resulted in severe environmental impacts, such as metal contamination. Manganese is a metal highly associated with mining activities, largely detected in mining dam collapses. This metal is considered necessary for different organisms, but it can be toxic and cause oxidative stress and genetic damage in fishes. In this study, we investigated the toxic effects of manganese on Astyanax lacustris, by exposing the fish individually to different concentrations of this metal (2.11, 5.00, and 10.43 mg/L) for 96 h. To assess the effects of manganese, we used biochemical biomarkers (glutathione S-transferase, catalase, and acetylcholinesterase enzyme activity) and the manganese bioaccumulation in different tissues (liver and gills). The obtained data showed that only at concentrations of 5.00 mg/L and 10.43 mg/L the activity of glutathione S-transferase differed significantly. Additionally, the acetylcholinesterase activity in the brain tissue was inhibited. The highest level of manganese bioaccumulation was observed in the liver and branchial tissue. Overall, we concluded that high concentrations of manganese may cause physiological changes in Astyanax lacustris.

Multiple biomarkers response of Astyanax lacustris (Teleostei: Characidae) exposed to manganese and temperature increase.

The present study aimed to evaluate the toxicity of Mn (6.65 mg/L) at different exposure times (96 h, 7, 14, and 21 days) and evaluate its possible toxic effects on the fish Astyanax lacustris through multi-biomarkers and the maximum critical temperature (CT Max). The results show an increase in the Mn accumulation (liver and gills) with increasing exposure time. The glutathione S-transferase (GST) activity showed differences in the group exposed to Mn for 96 h compared to the group exposed for 21 days. The acetylcholinesterase (AChE) activity increased in the fish exposed for 7 days compared to the control group. On the other hand, no genotoxic changes were observed. The CT Max showed that the loss of equilibrium of 50% of the fish occurs at a temperature of 39ºC, with and without the Mn presence. Furthermore, the catalase gene expression (oxidative stress) did not show alterations.

Do Manganese and Iron in Association Cause Biochemical and Genotoxic Changes in Oreochromis Niloticus (Teleostei: Cichlidae)?

The present study aimed to evaluate the toxicity of the association between Fe and Mn in Oreochromis niloticus through genotoxic (micronucleus test and comet assay) and biochemical (CAT and GST enzymes) assays. The tested treatments were T1 = control group (without metal addition), T2 = 2.60 mg L-1 of Fe + 0.2 mg L-1 of Mn, and T3 = 4.40 mg L-1 of Fe + 3.49 mg L-1 of Mn, during 96-h bioassays. All animals exposed to the metals showed a significant increase in erythrocyte micronucleus frequency and DNA damage. The hepatic GST activity increased two times in animals exposed to T3 compared to the control group. The results indicate that Fe + Mn caused genotoxic and biochemical changes in exposed fish. Therefore, excess metals in ecosystems, even those essential for organisms, can be dangerous for the local biota due to the risk associated with high concentrations of these metals.

Impact on Fertility Rate and Embryo-Larval Development Due to the Association Acidification, Ocean Warming and Lead Contamination of a Sea Urchin Echinometra lucunter (Echinodermata: Echinoidea).

Ocean warming and acidification can cause deleterious effects on marine biota, which may be potentialized when associated with metal pollution. Thus, the aim of this work was to evaluate the effects of pH decrease, temperature increase and lead contamination on fertility rate and embryo-larval development of Echinometra lucunter. Gametes and embryos were exposed at pH 8.2 (control) and 7.5; at 26°C (control) and 28°C; and at lead concentrations of 0 (control), 125, 250 and 500 µg/L. These conditions were tested individually and in combination. The fertilization rate of E. lucunter was only significantly reduced in the treatments where temperature was increased and in the treatment where pH decreased. However, the development rate of the pluteus larvae was significantly affected in the majority of treatments: metal contamination in the higher concentration; decreased pH in all metal concentrations; increased temperature in the highest metal concentration; decreased pH and increased temperature and all variables combined, which is decreased pH, increased temperature and metal contamination in relation to the control group (C). The development test was shown to be more sensitive than the fertilization test in all the studied scenarios. In general, the present study suggests that pH decrease, temperature increase and metal pollution may have a significant impact on E. lucunter reproductive cycle.

Metal bioaccumulation and its genotoxic effects on eggs and hatchlings of giant Amazon river turtle (Podocnemis expansa).

The aim of this study was to assess whether possible metal contamination in the sediment of the nests of giant Amazon river turtle, Podocnemis expansa, could contaminate eggs and hatchlings, triggering genotoxic damage. Therefore, sediments of P. expansa nests from two sites in the Brazilian Amazon were evaluated, with the first being collected at Araguaia River and the second at Crixás-Açu River. Newly hatched offspring, eggs, and sediments were collected from the beaches of these two rivers and the quantification of metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn) was carried out by atomic absorption spectroscopy. All targeted metals were found in both sediment and P. expansa biological samples collected on the beaches presenting higher concentrations in the sediment of Crixás-Açu River. Metals found in the eggshells before nesting and in the egg contents were maternally transferred. Moreover, augmented concentration of metals led by metal transfer from the nests sediments were detected in the eggshells after nesting (ENH) and in the newly hatched offspring (H). Probably this metal relocation to the newly hatchlings augmented the frequency of micronuclei in their blood, presenting 15.25‰ in hatchling found in Crixás-Açu River beaches and 10‰ in newly hatched animals from Araguaia River beaches. These results indicate the occurrence of maternal transfer of metals (essential or not) to the eggs in testudines as well as a transference from the sediments to the nesting eggs, triggering genotoxic effects on the hatchlings.

De novo assembly and annotation of the transcriptome of Astyanax lacustris liver unveil candidate genes to monitor response to environmental stress.

Astyanax lacustris is a freshwater characid fish species that inhabits small streams, lakes and rivers in South America. These fish are abundant in the wild and highly adaptable in captive, being considered a good model for ecotoxicological studies. Nevertheless, there are only shortcoming gene sequence information available in public databases, which hinder their use in more comprehensive investigations that employ sensitivity molecular biology techniques to assess gene expression profile for biomarker identification. In this study, we report the first de novo transcriptome of A. lacustris liver with the aim of improving gene sequence data available for this fish species. Illumina sequencing generated 79,102,610 raw reads, which were filtered in 62,041,259 high-quality transcripts. De novo assembly resulted in 93,888 unigenes and 120,674 isoforms of an average length of 909.12 and 1046.50 bp, respectively. 60,495 isoforms (50.13%) were functionally annotated against seven databases, retrieving homology queries for about 46% of all isoforms. Therefore, in this study we provide information of relevant genes associated to environmental stress and contamination of A. lacustris, enabling future ecotoxicological researches and other molecular studies using this fish species as model.

Accumulation of trace metals in eggs and hatchlings of Chelonia mydas.

BACKGROUND: The objective of this study was to verify the accumulation of trace metals in eggs and hatchlings of Chelonia mydas, evaluating if metal accumulation is originated from maternal transfer and/or from the incubation environment. Other assessments were also performed, as metal distribution in different tissues (blood, kidney, liver, muscle, and turtle shells) of newly hatched turtles, and genotoxic analysis, to verify possible damages caused by the presence of metals. METHODS: The assessments were carried out by quantifying Cd, Ni, Pb, Mn and Fe in egg sample collected during laying time (eggshells (ELT) and egg content (EC)), eggshells from newly hatched turtles (ENH), hatchlings tissues (H - blood, kidney, liver, muscle, and shell)) (n = 18 for each biological sample - 3 of each nest) and nest sediments (n = 6, one of each nest). Comparative analysis were made between ELT and ENH, as well as between egg content (EC) and the sum of tissue samples from hatchlings, using Mann-Whitney hypothesis test (p < 0,05). The amount of metals in different hatchling was quantified and followed by the Dunn post-test. A principal component analysis (PCA) was also employed. RESULTS: Metals studied were found in all investigated samples. The concentration of a great amount of investigated metals was significantly higher (P=<0.001) in eggshells from ENH than in ELT. An increase in Cd (2.16-fold), Pb (3.47-fold), Fe (6.83-fold) and Mn (195.57-fold) concentration was noticed in ENH. We also observed an increase in Fe (1.59-fold), Mn (1.74-fold) and Ni (1.59-fold) concentration in hatchling, when compared with EC, due to transfer from nest sediments. In relation to the hatchling's tissues, blood was shown to accumulate higher concentrations of Ni and Pb, while shells accumulated more Cd and Fe, and Mn is more associated with liver and kidney. Fe was the highest accumulated metal in both tissues, and muscles presented discrete concentrations of Ni, Mn, and Pb. A mean concentration of 1.25‰ MN was obtained in C. mydas hatchlings, indicating that the accumulation of metals in hatchlings didn't cause toxicology effects. CONCLUSION: Hatchlings accumulate metals through the maternal and sediment transfer, although the levels of metal accumulation were not enough to cause genotoxic damage.

The success of the fertilization and early larval development of the tropical sea urchin Echinometra lucunter (Echinodermata: Echinoidea) is affected by the pH decrease and temperature increase.

The decrease in the pH of oceans and the increase in their temperature are the two main problems observed in the marine ecosystems due to the increasing emission of CO2 in the atmosphere. Both conditions can affect the ecological processes of reproduction, recruitment and survival of the marine biota. Thus, the objective of the present study was to evaluate the effects of pH decrease and temperature increase of seawater on the fertilization success and embryo-larval development of a species of tropical sea urchin. For this purpose, fertilization success (gametes) and embryo-larval development rate were determined by exposing gametes and embryos to decreasing pH values (8.0 (control), 7.7, and 7.4) and increasing temperatures (26 (control), 28, 30, 34, and 38 °C). These conditions were tested associated with each other (in synergy). The gamete test was sensitive to all investigated scenarios, the fertilization success was significantly reduced in the conditions of increased temperature (28, 30, 34, and 38 °C) associated with the ideal pH (pH 8.0) and the conditions of reduced pH (pH 7.7, and 7.4), remaining unchanged only in the ideal condition (pH 8.0 + 26 °C). However, the embryo test displayed enhanced sensitivity in the scenarios of temperature increase (28, 30, 34, and 38 °C) associated with pH decrease conditions. A significantly reduction of 29%, 23% and 10% was observed in all tested pH values at 38 °C, when compared to the control group (80%, 79.5% and 63%, respectively). Therefore, the present study suggests that the occurrence of both scenarios may have a significant impact, in the coming years, on the population of Echinometra lucunter.

Morphological and histopathological changes in seahorse (Hippocampus reidi) gills after exposure to the water-accommodated fraction of diesel oil.

Industrial activities and urbanization are the main sources of pollutants in estuarine environments. Diesel, which is widely used in urban and port activities, is an important source of hydrocarbons in the aquatic environment, and its water-accommodated fraction (WAF) is toxic to the local biota. This study was performed to analyze the effects of diesel oil WAF on fish. Specifically, we characterized the gill morphology of the seahorse Hippocampus reidi and analyzed the histopathological changes in the gills after exposure to 50% diesel oil WAF. Acute (12, 24, 48, and 96 h) and subchronic (168 and 336 h) toxicity tests were performed. Furthermore, a recovery protocol was conducted: after exposure to 50% WAF for 168 h, the fish were transferred and kept in seawater without contaminants for 336 h, for a total experimental period of 504 h. The seahorse branchial apparatus was found to be tufted with short filaments; the apical surfaces of the pavement cells in the filament and lamellar epithelia formed "crests" and had microridges. Mitochondria-rich cells were distributed exclusively in the lamellar epithelium, while mucous cells were distributed in the filament epithelium. All pathologies observed after acute and subchronic exposure featured progressive time-dependent alterations of lamellar structure that might disrupt gill physiological and metabolic functions. During the recovery period, the gill alterations were gradually repaired.

Effects of water-accommodated fraction of diesel fuel on seahorse (Hippocampus reidi) biomarkers.

The present work aimed to investigate the effects of acute (12, 24, 48 and 96 h) and subchronic (168 and 336 h) exposure of seahorse, Hippocampus reidi to water-accommodated fraction (WAF) of diesel fuel on biotransformation parameters, antioxidant defenses and DNA integrity. In addition, a recovery experiment was performed, where the organisms remained in absence of the contaminant for 336 h, after WAF exposure for 168 h (totaling 504 h). At the end of each experimental protocol, the concentration of pyrene-, benzo(a)pyrene- and naphthalene-type metabolites in bile, hepatic activity of glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT), as well as lipid peroxidation (LPO) levels in hepatocytes, were analyzed, in addition to the DNA damage and the micronucleus (MN) test in the peripheral blood. It was observed that both acute and subchronic WAF exposure affected the investigated parameters in different ways. In general, the exposed groups presented higher mean values for the investigated parameters if compared with their respective controls. After the recovery experiment, the mean values of PAH metabolites, LPO, DNA damage and MN frequency were significantly lower than those of animals exposed for 168 h, indicating that the recovery period was appropriately long for the evaluated biomarkers return to the control levels. The results indicated that the selected H. reidi biomarkers proved to be adequate and complementary tools in determining the first impacts of acute and subchronic exposure caused by WAF of diesel fuel in fish, as well as their recovery in clean water.

Genotoxic Damages and Bioaccumulation of Cadmium in Geophagus Brasiliensis (Quoy & Gaimard, 1824).

The toxic effects of cadmium (Cd) in Geophagus brasiliensis was investigated in the present study. For this, 32 specimens of G. brasiliensis were exposed in individual aquaria to Cd concentrations (0.00, 0.01, 0.07, and 0.67 mg/L) for 14 days. The micronuclei test did not detect the genotoxic damage at the studied concentrations and time of exposure. However, the comet assay proved to be more efficient, as DNA damage was found in the animals exposed to the higher Cd concentrations. Finally, exposure of G. brasiliensis to Cd was associated with Cd accumulation in the gills, while only the animals exposed to 0.67 mg/L of Cd exhibited muscle accumulation. These results demonstrate that Cd concentrations over 0.07 mg/L caused genotoxic damage, as well as Cd accumulation in G. brasiliensis individuals after a 14 days exposure.

Genotoxic, biochemical and bioconcentration effects of manganese on Oreochromis niloticus (Cichlidae).

Manganese and iron were found at high concentrations (3.61 mg/L and 19.8 mg/L, respectively) in the water of the Rio Doce after the dams of Fundão and Santarém broke in Mariana/MG (Brazil). These same metals were found in fish and crustacean muscle (15 mg/kg and 8 mg/kg wet weight, respectively) in the specimens collected near the Rio Doce's outfall. Due to the variation in Mn concentration found in the lower Rio Doce, this study aimed to determine the effects of Mn in Oreochromis niloticus, at the concentrations allowed by CONAMA, and in concentrations found in the Rio Doce after the dams broke. The animals were exposed to the following dissolved concentrations: control group (0.0 mg/L), 0.2; 1.5 and 2.9 mg/L manganese for 96 h. In addition, a positive control was conducted, injecting intraperitoneally with cyclophosphamide (at 25 mg/kg). These exposures caused significant erythrocyte micronucleus formation in the organisms exposed to the highest concentration, as well a significant increase in the DNA damage index of erythrocytes from organisms exposed to 1.5 mg/L and 2.9 mg/L treatments. The glutathione S-transferase enzyme activity also showed a significant increase in the liver of the organisms exposed to 2.9 mg/L. However, catalase activity increased significantly in the gills of the animals exposed to all concentrations of manganese that were tested. Manganese bioconcentrated in greater quantities in the liver than the gills. Thus, manganese causes significant damage to genetic material, generates nuclear abnormalities, activates the body's detoxification system and can accumulate in animal tissue.

Effects of the water-soluble fraction of diesel oil (WSD) on the fertilization and development of a sea urchin (Echinometra lucunter).

Considering the high number of accidents with diesel oil spills occurring in the marine ecosystem, toxicity tests aimed at assessing the effects of this pollutant on biota are necessary and urgent. Thus, the present study aimed to evaluate the toxicity of the soluble fraction of diesel oil (WSD) in the fertilization success of gametes and pluteu larvae of the sea urchin Echinometra lucunter. To do this, gametes and embryos were exposed to concentrations of 0% (control group), 0.5%, 1.5% and 2.5% of WSD. The fertilization success of exposed gametes and embryos were reduced significantly when compared to the control group in all tested concentrations. With this finding, it is evident that diesel oil can be significantly promoted in the early and adult life stages of a particular organism, and a better way of evaluating this toxicity is through the analysis of contaminant effects throughout the reproductive cycle of a species.

Water-soluble fraction of petroleum induces genotoxicity and morphological effects in fat snook (Centropomus parallelus).

Petroleum hydrocarbons are one of the primary organic chemicals found in water bodies, and the water-soluble fraction of petroleum (WSFP) may be responsible for much of the toxic effects. In the present study, genotoxicity assays and histopathological analysis of the gills were analyzed for two experimental protocols: 1) Juvenile Centropomus parallelus were exposed to different concentrations of WFSP (0%, 25%, 50% and 75%) for 96h; 2) A second fish group was exposed to 50% WFSP for 168h followed by a post-exposure period for 168h in clean water (recovery). The total benzene, toluene, ethyl benzene and xylene (BTEX) and polycyclic aromatic hydrocarbon (PAH) concentrations at time 0 were 254µgL-1 and 4.72µgL-1 in 25%; 552.9µgL-1 and 9.36µgL-1 in 50%; and 842.4µgL-1 and 9.97µgL-1 in 75% WSFP, respectively. Based on the alkaline comet assay, the damage index (DI) values of fish exposed to 25% WSFP for 96h were significantly higher than those in the control group, and in the micronucleus test, the higher damage values were found in fish exposed to 75% WSFP. Furthermore, this last genotoxic test showed recovery after 168h. At all concentrations of WSFP, several histopathological changes were observed, and overall, most of these changes observed in the gills were classified as proliferative changes and represented a protective mechanism against pollutant uptake. Based on the recovery experiment, the damage was also significantly reduced after recovery. Our results showed that short-term exposure to WSFP compounds triggered cellular alterations in C. parallelus, but total recovery did not occur with time. Additionally, the different periods of exposure were not sufficient to induce severe gill damage in C. parallelus. Moreover, this fish demonstrated its usefulness as a sentinel species.

Effects of manganese on fat snook Centropomus parallelus (Carangaria: Centropomidae) exposed to different temperatures

This study evaluates the effects of exposure to manganese (Mn2+) for 96 hours at two different temperatures (24 and 27°C) on juveniles of Centropomus parallelus through the activities of glutathione S-transferase (GST) and catalase (CAT), micronuclei test (MN) and comet assay. The GST activity did not show any significant difference between the groups exposed to Mn2+ and the respective control groups; in contrast, a major increase in the CAT activity was observed at 27°C in the group exposed to Mn2+ compared to the control group. The genotoxic analyses showed that in all animals exposed to Mn2+, the number of red cells with micronuclei increased significantly compared to the respective control groups. There was also a significant increase in the incidence of DNA damage in the groups exposed to Mn2+. At a temperature of 24ºC, animals exposed to Mn2+ had more DNA damage than those at 27°C. It is likely that the increase in temperature can also induce oxidative stress. Thus, we conclude that manganese is toxic to the fat snook juveniles, causing genotoxic damage, and when associated with an increase in temperature, manganese can also provoke an increase in oxidative stress.(AU)

Este estudo avaliou os efeitos da exposição ao manganês (Mn2+), após 96 horas, a duas temperaturas (24 e 27°C) em juvenis de Centropomus parallelus por meio de análises bioquímicas (atividade das enzimas glutationa S-transferase (GST) e catalase (CAT)) e genotóxicas (teste do micronúcleo e ensaio cometa). A atividade da GST não mostrou diferença significativa entre os grupos expostos ao Mn2+ e os seus respectivos grupos controle, enquanto que um aumento significativo na atividade da CAT foi observado a 27°C no grupo exposto ao Mn2+, quando comparado ao grupo controle. As análises genotóxicas mostraram que os animais expostos ao Mn2+ tiveram aumento significativo na quantidade de células com micronúcleo em relação aos seus grupos de controles. Houve também aumento significativo na incidência de danos ao DNA nos grupos expostos a esse contaminante. Na temperatura de 24°C, os animais expostos ao Mn2+ tiveram maior quantidade de danos no DNA em relação a 27°C. É provável que o aumento da temperatura também possa induzir o estresse oxidativo. Assim, concluímos que o manganês é tóxico para os juvenis de robalo, causando dano genotóxico, e quando associado a um aumento da temperatura, também pode provocar um aumento no estresse oxidativo.(AU)

The effects of subchronic exposure to copper in fat snook (Centropomus parallelus).

Anthropogenic processes affect different communities through the release of contaminated effluents into water bodies. Copper can be found in the effluents of most industrial processes and in other effluent types. The fat snook Centropomus parallelus, found from Florida in the United States to southern Brazil, is of great economic importance and is used as a food resource near the coast. This study aimed to determine the effects of copper on C. parallelus. The fish were exposed for 30 or 60 days to treatments of 0, 13 and 26µgCuL(-1). Genotoxic effects of copper were observed in the micronuclei, especially in individuals exposed to higher concentrations. Copper exposure also had a negative effect on the growth of fat snook individuals. Compared to the control group without the addition of metal, an accumulation of metal was observed in the gills of exposed fish, an effect that was not found in the muscle.

Genetic and biochemical effects induced by iron ore, Fe and Mn exposure in tadpoles of the bullfrog Lithobates catesbeianus.

For decades, the extraction of minerals has intensified in order to meet the demand of industry. Iron ore deposits are important sources of metals, such as iron (Fe) and manganese (Mn). The particulate ores can be dispersed during extraction, transport and storage, with potential to induce biological impacts. Amphibians are very sensitive to environmental stressors. Therefore, the present study aimed to assess the effects of iron ore, Fe and Mn exposure during the metamorphosis of Lithobates catesbeianus. Endpoints analyzed included morphological (biometrical and developmental analyses), whole body Fe and Mn concentration in, plasma ferritin concentration, erythrocyte DNA damage (measured through comet assay and micronucleus test) and liver activity of enzymes involved in oxidative status [glutathione S-transferase (GST) and catalase (CAT)]. Tadpoles were kept under control condition (no contaminant addition) or exposed to iron ore (3.79mg/L as fine particulate matter); Fe (nominal concentration: 0.51mg/L Fe as C10H12FeN2NaO8; Fe-EDTA); and Mn (nominal concentration: 5.23mg/L Mn as 4H2O.MnCl2) for 30 days. Virtually, no mortality was observed, except for one tadpole found dead in the iron ore treatment. However, tadpoles exposed to iron ore had longer tail than those kept under control conditions while tadpoles exposed to manganese chloride showed higher body length than control ones. Exposure to Fe and Mn induced a delay in tadpole metamorphosis, especially when these metals are presented not as a mixture (iron ore). Tadpoles exposed to iron ore had increased whole body Fe and Mn while those exposed to Fe and Mn accumulated each metal individually. Tadpoles exposed to any of the contaminants tested showed a significant increase in erythrocyte DNA damage and frequency of micronuclei. In addition, they showed higher liver GST activity respect with those kept under control conditions. Plasma ferritin concentration and liver CAT activity were higher only in tadpoles exposed to iron ore. These findings indicated that tadpoles accumulated Fe and Mn at the whole body level after exposure to the single metals or to their mixture as iron ore. In addition, they indicate that Fe and Mn accumulation can induce oxidative stress with consequent significant developmental, genotoxic and biochemical effects in L. catesbeianus tadpoles.

Acute toxicity of the water-soluble fraction of diesel in Prochilodus vimboides Kner (Characiformes: Prochilodontidae)

Diesel oil can be a source of contamination in aquatic environments, mainly as a result of spills. The effects of the water-soluble fraction of diesel (WSF) on Prochilodus vimboides were assessed. Fish were exposed to three different WSF dilutions for up to 96 h and were compared to a control group. Damages in the fragments of DNA were analyzed using the Comet assay. The presence of erytrocyts abnormalities was assessed by micronucleus test. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity and the accumulation of copper in gills were also analyzed. Fish exposed for 96 h had higher rates of damage than those exposed for 24 h. There was no significant difference regarding the presence of micronuclei between exposed and control fish and between 24-h and 96-h exposures. For AST, no significant difference was observed between samples collected at the two exposure times. Fish exposed to a 1:100 dilution of WSF showed higher activity of the enzyme ALT than the control fish after a 24-h exposure period. There was no bioaccumulation of copper in the gills. We conclude that the genotoxic effects of WSF in the cells are more evident in P. vimboides during an acute exposure.

O óleo diesel pode ser uma fonte de contaminação em ambientes aquáticos, principalmente como resultado de derrames acidentais. Foram avaliados os efeitos da fração solúvel do óleo diesel (FSO) em Prochilodus vimboides. Os peixes foram expostos a três diferentes diluições da FSO por até 96 horas e comparados com um grupo controle. Os danos nos fragmentos de DNA foram analisados utilizando o ensaio Cometa. A presença de anormalidades nos eritrócitos foi avaliada pelo teste do micronúcleo. A atividade da Aspartato aminotransferase (AST) e alanina aminotransferase (ALT) e da acumulação de cobre nas brânquias também foram analisados. Os peixes expostos por 96 h tiveram maiores taxas de danos do que aqueles expostos por 24 h. Não houve diferença significativa quanto à presença de micronúcleos entre os peixes expostos e controle e entre 24 e 96 h exposições. Para AST, não foi observada diferença significativa entre as amostras coletadas em dois tempos de exposição. Os peixes expostos a uma diluição de 1:100 do FSO apresentaram maior atividade da enzima ALT do que os peixes do controle após um período de exposição de 24 horas. Não houve bioacumulação de cobre nas brânquias. Os efeitos genotóxicos nas células foram os mais evidentes em P. vimboides durante a exposição aguda a FSO.

Genotoxic and morphological damage in Hippocampus reidi exposed to crude oil.

The present article investigates the responses of Hippocampus reidi exposed to crude oil (10mL/L) for time periods that are characteristic of acute (12, 24, 48 and 96h) and subchronic (168 and 336h) and its recovery at 168h, such as to assess H. reidi as a good sentinel species. These responses were examined by genotoxic and morphologic analyses. There was a control group (n=8) for each group exposed to crude oil (n=8). The results revealed the occurrence of genotoxic damage in erythrocytes of all specimens exposed to crude oil. The damage index (DI) observed for all exposure times were significantly higher compared to those of the respective control groups; the highest DI was observed in specimens exposed to crude oil for 168h. The group exposed to crude oil for 96h had the highest values of micronuclei than all other exposure times. Microscopic inspection of the H. reidi gills revealed the presence of several histopathological changes, all of which were minor severity (structural normal gills). The recovery experiment revealed a significant reduction in genotoxic damages, however the period of 168h was not sufficient to recuperate the histopathology damages. The Seahorse has presented significant genotoxic responses after exposure to crude oil. Furthermore, it is a sedentary fish and is widely distributed; in conclusion this specie can be considered an excellent sentinel organism.

Avaliação da toxicidade do cobre para o piauçu ( Leporinus macrocephalus, Garavello & Britski, 1988 ) por meio de parâmetros leucocitários e enzimáticos / Evaluation of the toxicity of copper for piauçu ( Leporinus macrocephalus ) through leukocyte and enzymatic parameters

Como forma de monitoramento de áreas degradadas, testes de toxicidade têm sido amplamente utilizados. Este trabalho teve como objetivo avaliar a toxicidade do cobre para o piauçu a partir da determinação da CL50 96h e da análise de alterações nos padrões enzimáticos e leucocitários, em exposição subletal (25 e 50% da concentração letal) por 96h. A CL50 96h do cobre para o piauçu foi 0,09 ± 0,03 mg L-1. Após a exposição às concentrações subletal, os valores das concentrações enzimáticas de Alanina Aminotrasferase e Aspartato Aminotransferase não apresentaram diferença significativa entre os indivíduos do grupo-controle e dos expostos ao metal. A glicose plasmática apresentou aumento significativo nos peixes expostos a 25 e 50% da CL50, quando comparados ao controle. O eosinófilo, o linfócito e o neutrófilo não apresentaram diferença significativa do grupo-controle. Os trombócitos aumentaram significativamente nos peixes expostos a 50% da CL50; os monócitos, nos peixes expostos a 25 e 50% da CL50. Os resultados indicam que o piauçu é uma espécie sensível aos efeitos letais do cobre e que a exposição a concentrações subletais causa um distúrbio imunológico, porém não induz dano hepático, de acordo com as enzimas mensuradas.

Toxicity tests have been widely used as a form of monitoring degraded areas. This work has as objective to evaluate the toxicity of copper for Piauçu from the determination of LC50 for 96 hours and analysis of alterations in the enzymatic and leukocyte patterns, in sublethal exposure (25 and 50% of the lethal concentration) for 96 hours. The LC50 of copper for Piauçu, during 96 hours, is 0.09±0.03 mg L-1 Cu2+. After exposure to the sublethal concentrations, enzymatic concentrations of Alanine Aminotrasferase and Aspartate Aminotransferase did not show any significant difference between the individuals of the control and metal groups. Plasma glucose showed a significant increase in fish exposed to 25 and 50% of LC50, when compared with control. Eosinophil, lymphocyte and neutrophil showed no significant difference from the control group. Thrombocytes increased significantly in the fish exposed to 50% of the LC50, as did monocytes in fish exposed to 25 and 50% of LC50. The results indicate that Piauçu is a species sensitive to the lethal effects of copper, and that exposure to the sublethal concentrations causes immune disorder; however, it does not induce liver damage according with the measured enzymes.