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The biotransformation ability of the organism is the result of organ-specific responses. This paper presents a molecular and biochemical approach to elucidate the biotransformation mechanisms in different organs of Prochilodus lineatus induced at 6, 24, and 96 h after a benzo[a]pyrene (B[a]P) injection. The induction in cyp1a transcription showed an organ-specific intensity at every tested time time. The EROD (ethoxyresorufin-O-deethylase) activity increased rapidly (6 h) in the liver and the kidney; the gills and the brain showed an increase at 24 h; and the gills demonstrated the highest activity among all the organs tested. There was no increase in glutathione S-transferase (GST) activity or lipoperoxidation. The decreased hepatic glutathione content (GSH) may be due to its role as an antioxidant. B[a]P was detected in the bile, confirming the xenobiotic efflux from the metabolizing organs. The gills, liver, brain, and kidney of P. lineatus presented an integrated mechanism to deal with the xenobiotic biotransformation.

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Microplastics (MP) are emerging contaminants widely found in aquatic ecosystems. In addition to MP toxicity itself, there is increasing concern about the MP adsorption capacity and the interactive effects with other contaminants, such as copper. The objective of this research was to investigate the effects of polyethylene microplastic and its association with copper (Cu) in genotoxic, biochemical, and physiological biomarkers of the neotropical teleost Prochilodus lineatus. Fish were exposed for 24 and 96 h to MP (20 µg L-1) and Cu (10 µg L-1) and MP + Cu. The results showed that MP and Cu, both isolated and in combination, promoted DNA damage in erythrocytes (96 h) and liver cells (24 and 96 h) indicating that MP and Cu are genotoxic. Fish exposed only to Cu (96 h) showed a decrease in lipid peroxidation in the liver despite of the decrease in glutathione content, indicating the efficiency of other antioxidant defenses. Brain acetylcholinesterase was inhibited in the animals from all the treatments. Although MP did not influence on Cu accumulation in tissues, decreased plasma Na+ and Ca2+ (24 h) occurred after the exposure to MP and Cu, isolated and combined. Exposure to MP and MP + Cu resulted in decreased activity of Ca2+-ATPase (24 h). Taken altogether, these results showed that MP and Cu depicted genotoxic, neurotoxic, and physiological effects on P. lineatus, both alone and combined. An interaction between Cu and MP was observed in plasma Ca2+, where the combination of both contaminants caused a greater effect than the contaminants alone.

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Copper nanoparticles can contaminate the aquatic environment, but their effects on fish and how they may differ from copper salts is not understood. Thus, in this work we compare the sublethal effects of copper nanoparticles (nCu) and copper chloride (Cu) on the freshwater teleost Prochilodus lineatus, known for its sensitivity to copper. Juveniles (n = 8/group) were exposed to 20 µg L-1 of copper as CuCl2 (Cu), 40 µg L-1 of copper nanoparticles (nCu), or only water (control), for 96 h. These concentrations were chosen to achieve similar dissolved copper concentration in both treatments (Cu: 10.29 ± 0.94 µg L-1; nCu: 12.16 ± 1.77 µg L-1). After the exposure, the following biological parameters were evaluated: copper accumulation in the gills, liver, gastrointestinal tract, kidney, and muscle; hematocrit (Ht) and hemoglobin content (Hb); branchial activity of Na+-K+-ATPase (NaKATP), H+-ATPase (HATP), Ca2+-ATPase (CaATP), and carbonic anhydrase (CA); glutathione content (GSH) and lipid peroxidation (LPO) in the liver; acetylcholinesterase activity (AChE) in the brain and muscle; and histopathology of the gills and liver. The gills of Cu-exposed fish were adversely affected, with increased copper content, inhibition of H+-ATPase and Ca2+-ATPase, and histological damage, including proliferation of mitochondria rich cells and/or mucous cells. In addition, LPO levels increased in the liver of Cu-exposed fish, indicating the occurrence of oxidative stress. Exposure to nCu promoted a decrease in Ht and Hb, indicating anemia, and an increase in branchial Na+-K+-ATPase and H+-ATPase activities, which can be an adaptive response to metabolic acidosis. Within the chosen biomarkers and the conditions tested, copper nanoparticles were less toxic than copper. However, the effects promoted by the nanoparticles were different from those promoted by copper. These results emphasize the need for a better understanding of copper nanoparticles toxicity in order to establish safe concentrations and avoid environment impacts.

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Atrazine (ATZ) is a widely used herbicide that has the potential to contaminate the environment and cause deleterious effects on non-target organisms. Release systems for ATZ have been developed to minimize this contamination, such as nanocapsules prepared with poly (ε-caprolactone) (PCL). The objective of this work was to investigate the effects of nanoencapsulated ATZ compared to ATZ on biomarkers of the freshwater teleost Prochilodus lineatus. The fish were exposed for 24 and 96 h to nanoencapsulated ATZ (nATZ) and atrazine (ATZ) at concentrations of 2 and 20 µg L-1, just to the PCL nanocapsules without the herbicide (NANO) in the corresponding amounts or only to dechlorinated water (CTR). The results showed that nATZ was less toxic compared to ATZ, as it did not promote an increase in glycemia, alterations in antioxidants, nor in carbonic anhydrase enzyme activity, and no increase in the frequency of micronuclei and other nuclear erythrocyte abnormalities either. However, exposure to nATZ, as well as to ATZ and PCL nanocapsules, resulted in a reduction in hemoglobin content, increase in erythrocyte DNA damage, as well as changes in Ca2+-ATPase activity, leading to a decrease in plasma Ca+2. The Integrated Biomarker Response Index (IBR) depicted that exposure to ATZ promoted changes in a greater number of biomarkers compared to nATZ, indicating that the nanoencapsulation of the herbicide protected the animal from the effects of ATZ.

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The aim of this study was to investigate the responses of biomarkers in feral and caged fish and the capacity of these biomarkers to discriminate contamination levels along a stream located in an agricultural area in Southern Brazil. Specimens of the Neotropical fish, Astyanax altiparanae, were confined for 168h in three lakes along the stream. Additionally, during the weeks of in situ exposure, wild specimens of this species were collected from the same sites. Biochemical biomarkers were analyzed, such as phase I biotransformation enzyme 7-ethoxyresorufin-O-deethylase (EROD) and phase II biotransformation enzyme glutathione S-transferase, and we also determined hepatic and branchial levels of non-protein thiols (NPSH), oxidative damage such as lipid peroxidation (LPO), and acetylcholinesterase (AChE) activity in muscle and brain. Genetic biomarkers such as DNA breaks (comet assay), frequency of micronuclei (MN) and erythrocytic nuclear abnormalities (ENA) were also examined. The results indicate that the most sensitive biomarkers for discriminating contamination levels are DNA breaks, LPO and AChE activity. Similar results were obtained for both caged and feral fish. The biomarkers that reflect the results of cumulative events, such as ENA, were more discriminative for chronically exposed specimens (feral fishes). Analyzing biomarkers using an integrated response index showed that both approaches (using feral and caged A. altiparanae) were effective for discriminating contamination levels along the stream, corroborating the results of chemical analyses for selected pesticides. Taken together, these results highlight the importance of biomarker selection and show that both approaches (caged and feral fish) are satisfactory for evaluating water quality in streams impacted by agricultural activities.

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Two fish species, known as lambaris (Astyanax altiparannae and A. fasciatus) were collected from the following streams in Londrina: Cambé (lake Igapó IV), Três Bocas, Apertados and Capivara. After capture blood samples and gills were immediately removed. Gills were fixed in Bouin and processed for light microscopy. A small amount of blood was used for hemoglobin determination and sodium and glucose plasma concentrations were determined after blood centrifugation. Animals from Cambé and Capivara streams showed certain severe histopathological alterations, such as lamellar aneurism and epithelial lifting. These fish also showed higher blood sodium concentration and a reduction of blood glucose when compared to fish from Três Bocas stream. Fish from Capivara showed a decrease in hemoglobin content when compared to animals from Cambé stream. Higher incidence of histological and physiological alterations observed in fish from Cambé and Capivara stream clearly indicates the animals health impairment

Duas espécies de lambaris (Astyanax altiparanae e A. fasciatus) foram coletadas nos seguintes ribeirões do município de Londrina: Cambé (no lago Igapó IV), Três Bocas, Apertados e córrego Capivara. Imediatamente após a coleta dos peixes, amostras sangüíneas e brânquias foram retiradas. As brânquias foram fixadas em Bouin e processadas para microscopia óptica. Do sangue coletado uma alíquota foi utilizada para dosagem de hemoglobina e o restante foi centrifugado para a determinação da concentração plasmática de sódio e glicose. Os animais provenientes do Cambé e Capivara apresentaram alterações histopatológicas severas, tais como: aneurisma lamelar e elevação epitelial. Estes animais também mostraram maior teor plasmático de sódio e redução da glicemia quando comparados com os peixes do Três Bocas. Os lambaris provenientes do Capivara apresentaram decréscimo significativo do conteúdo de hemoglobina em relação aos animais coletados no Cambé. A maior incidência de alterações histológicas e fisiológicas nos lambaris procedentes do ribeirão Cambé e do córrego Capivara indica claramente o comprometimento da saúde destes peixes e da qualidade da água destes locais

RESUMO

Two fish species, known as lambaris (Astyanax altiparannae and A. fasciatus) were collected from the following streams in Londrina: Cambé (lake Igapó IV), Três Bocas, Apertados and Capivara. After capture blood samples and gills were immediately removed. Gills were fixed in Bouin and processed for light microscopy. A small amount of blood was used for hemoglobin determination and sodium and glucose plasma concentrations were determined after blood centrifugation. Animals from Cambé and Capivara streams showed certain severe histopathological alterations, such as lamellar aneurism and epithelial lifting. These fish also showed higher blood sodium concentration and a reduction of blood glucose when compared to fish from Três Bocas stream. Fish from Capivara showed a decrease in hemoglobin content when compared to animals from Cambé stream. Higher incidence of histological and physiological alterations observed in fish from Cambé and Capivara stream clearly indicates the animals health impairment

Duas espécies de lambaris (Astyanax altiparanae e A. fasciatus) foram coletadas nos seguintes ribeirões do município de Londrina: Cambé (no lago Igapó IV), Três Bocas, Apertados e córrego Capivara. Imediatamente após a coleta dos peixes, amostras sangüíneas e brânquias foram retiradas. As brânquias foram fixadas em Bouin e processadas para microscopia óptica. Do sangue coletado uma alíquota foi utilizada para dosagem de hemoglobina e o restante foi centrifugado para a determinação da concentração plasmática de sódio e glicose. Os animais provenientes do Cambé e Capivara apresentaram alterações histopatológicas severas, tais como: aneurisma lamelar e elevação epitelial. Estes animais também mostraram maior teor plasmático de sódio e redução da glicemia quando comparados com os peixes do Três Bocas. Os lambaris provenientes do Capivara apresentaram decréscimo significativo do conteúdo de hemoglobina em relação aos animais coletados no Cambé. A maior incidência de alterações histológicas e fisiológicas nos lambaris procedentes do ribeirão Cambé e do córrego Capivara indica claramente o comprometimento da saúde destes peixes e da qualidade da água destes locais