Bioaccessibility and bioavailability of essential and potentially toxic trace elements in potato cultivars: A comprehensive nutritional evaluation.

Among the most consumed foods in the world is potato, which occupies the first place as a non-grain commodity, demonstrating the importance of its assessment concerning the population's food safety. In this study, the nutrients Ca, Mg, K, P, Cu, Mn, Fe, and Zn and the potentially toxic trace elements Cd, Cr, and Pb were evaluated considering their total contents, bioaccessible and bioavailable fractions in different potato cultivars, in an unpublished approach in the literature. The in vitro standard gastrointestinal digestion method (INFOGEST) and a model of the intestinal epithelial barrier using the Caco-2 cell line were applied for investigate the presence of metals in potato. For the macroelements, the bioaccessibility (% w/w) varied in the ranges: K (57-72 %), P (59-76 %), Mg (83-103 %), and Ca (30-123 %), whereas for the microelements were: Cu (27-74 %) and Mn (4.22-12.02, 60-119 %). The potentially of trace toxic elements, Cd and Pb, were found in 75 % of the samples, however, all the concentration values were below the maximum levels allowed of 0.10 µg/g. Chromium was determined only in potato peels and has no maximum established level. The bioaccessible and bioavailable fractions of Cd, Cr, and Pb were below the limits of quantification of the spectrometric methods (LOQ - µg/L: 0.063 Cd, 0.65 Cr, and 0.44 Pb). The potato samples were considered safe for consumption regarding the presence of potentially toxic trace elements, with a remarkable nutritional contribution.

Microcystin and pyriproxyfen are toxic to early stages of development in Rhamdia quelen: An experimental and modelling study.

The recent increase of freshwater eutrophication has favored cyanobacteria blooms and consequently the increase of toxins such as microcystin-LR in aquatic environments, but few is know about the associated effect of toxin and other compounds. Pyriproxyfen is an insecticide indicated by WHO (World Health Organization) to control Aedes aegypti mosquito (vector of Dengue, Chikungunya and Zika diseases), however, the effects are not well described to non-target species, such as fish. The early life stages (ELS) of fish are more sensitive to chemical stress due to higher metabolic rate, immature immune system and high superficial area/volume ratio. In the current study, ELS of R. quelen a Neotropical fish were exposed to environmentally realistic concentrations of microcystin (1, 10 and 100 µg L-1; M1, M2 and M3 groups, respectively) from an algal extract, pyriproxyfen (1 and 10 µg L-1, P1 and P2) and their association (co-exposure). The hatching, survival and larvae deformities were analyzed, and applied a mathematical model to evaluate the effects on the population size along further generations. Both compounds were toxic to embryos/larvae of fish, but the effects were more pronounced in M2, P1M2 and P2M1 for hatching and M2, P1M2, P2M1 and P1 for survival. Deformities prevailed in groups exposed to the chemicals at 48 hpf (hours post-fertilization) were suggestions of toxicological interaction in P1M2, P2M1 and P2M2 at 48 and 72 hpf. In 96 hpf, the levels of deformities were lower than in previous times. Model predicted population density over 100 years decreased to lower than 0.5 (50%) in all groups, except for P1M1, indicating risk of extinction. P1M2 had the worse results, followed by M2, P1M3 and P2M1. Cyanobacterial blooms can lead to microcystin-LR levels higher than M2 (10 µg L-1), and the suggestion of toxicological interaction with pyriproxyfen is relevant because both compounds may potentially coexist in aquatic environments. Finally, mathematical models may provide an ecological interpretation of the risk of exposure of fish.

Cylindrospermopsin effects on cell viability and redox milieu of Neotropical fish Hoplias malabaricus hepatocytes.

Cylindrospermopsin (CYN) is a cyanotoxin that is cytotoxic to a wide variety of cells, particularly to the hepatocytes. In this study, the toxic effects of purified CYN were investigated in primary cultured hepatocytes of Neotropical fish Hoplias malabaricus. After isolation, attachment, and recovery for 72 h, the cells were exposed for 72 h to 0, 0.1, 1.0, 10, and 100 µg l-1 of CYN. Then, cell viability and a set of oxidative stress biomarker responses were determined. Catalase, superoxide dismutase, glucose-6-phosphate dehydrogenase, and glutathione S-transferase activities were not affected by exposure to CYN. Concentration-dependent decrease of glutathione reductase activity occurred for most CYN-exposed groups, whereas non-protein thiol content increased only for the highest CYN concentration. Lipid peroxidation, protein carbonylation, and DNA damage levels were not altered, but reactive oxygen species levels increased in the cells exposed to the highest concentration of CYN. Cell viability decreased in all the groups exposed to CYN. Thus, CYN may cause a slight change in redox balance, but it is not the main cause of cell death in H. malabaricus hepatocytes.

Effects of realistic concentrations of TiO2 and ZnO nanoparticles in Prochilodus lineatus juvenile fish.

The impact of nanoparticles on fish health is still a matter of debate, since nanotechnology is quite recent. In this study, freshwater benthonic juvenile fish Prochilodus lineatus were exposed through water to three concentrations of TiO2 (0.1, 1, and 10 µg l(-1)) and ZnO (7, 70, and 700 µg l(-1)) nanoparticles, as well as to a mixture of both (TiO2 1 µg l(-1) + ZnO 70 µg l(-1)) for 5 and 30 days. Nanoparticle characterization revealed an increase of aggregate size in the function of concentration, but suspensions were generally stable. Fish mortality was high at subchronic exposure to 70 and 700 µg l(-1) of ZnO. Nanoparticle exposure led to decreased acetylcholinesterase activity either in the muscle or in the brain, depending on particle composition (muscle-TiO2 10 µg l(-1); brain-ZnO 7 and 700 µg l(-1)), and protein oxidative damage increased in the brain (ZnO 70 µg l(-1)) and gills (ZnO 70 µg l(-1) and mixture) but not in the liver. Exposed fish had more frequent alterations in the liver (necrosis, vascular congestion, leukocyte infiltration, and basophilic foci) and gills (hyperplasia and epithelial damages, e.g., epithelial disorganization and epithelial loss) than the control fish. Thus, predicted concentrations of TiO2 and ZnO nanoparticles caused detectable effects on P. lineatus that may have important consequences to fish health. But, these effects are much more subtle than those usually reported in the scientific literature for high concentrations or doses of metal nanoparticles.

Cadmium effects on early development of chick embryos.

The toxic potential of cadmium (Cd) is well-documented for young and adult vertebrates, but it is still poorly understood in the early stages of development. In this study, cadmium effects were investigated on Gallus gallus embryos after injection of CdCl(2) (5µM and 50µM) within the egg air chamber, and incubation for 48 and 72h. After exposure, morphological and enzymatic analyses for glucose-6-phosphate dehydrogenase (G6PDH) and glutathione S-transferase (GST) were performed. Critical morphological abnormalities occurred after exposure to the highest concentration of cadmium, mainly in the cephalic region, indicating the powerful teratogenic effect of Cd to chick embryos. Cd exposure did not alter enzymatic activities when compared to the control group, but the levels of G6PDH activity were highest in older embryos at stage 19, indicating that antioxidant defenses are not so robust in the earliest embryo stages.

Bioaccumulation and related effects of PCBs and organochlorinated pesticides in freshwater fish Hypostomus commersoni.

Few studies have investigated the bioaccumulation of persistent organic pollutants (POPs) in Brazilian native freshwater fish. In order to evaluate the bioavailability, potential risk to human exposure and the effects of POPs in the fish Hypostomus commersoni, muscle and liver samples of thirteen specimens were collected in a lake located in the city of Ponta Grossa (Parana State, Southern Brazil). Also, the liver and gills were considered for histopathological studies, and oxidative stress was investigated in the liver. Expressive concentrations of POPs were observed in the liver and muscle, with a total of 427 ± 78.7 and 69.2 ± 18.1 ng g(-1) dry weights of polychlorinated biphenyls (PCBs), respectively. Negative correlations between the concentration of several POPs and glutathione S-transferase and glucose-6-phosphate dehydrogenase were found. Otherwise, the cholinesterase activity in the muscle and brain presented positive correlations with the concentration of POPs. The hepatic bioaccumulation of some banned pesticides like aldrin, dieldrin and DDT was associated with various histopathological findings in the liver and gills. Necrotic areas, fibrosis, leukocyte infiltration, and the absence of macrophage centers were observed in the liver, indicating both chronic exposure and immunological suppression. Neoplasic changes were observed in the gills, confirming the carcinogenic potential reported for some of the investigated pollutants. The current work was the first to study the bioaccumulation of POPs in H. commersoni, an important species in ecological aspects and as a vehicle to human exposure to PCBs and organochlorine pesticides (OCPs).

Cellular responses of Prochilodus lineatus hepatocytes after cylindrospermopsin exposure.

Cylindrospermopsin is a potent toxicant for eukaryotic cells produced by several cyanobacteria. Recently, primary hepatocyte cultures of Neotropical fish have been established, demonstrating to be a quite efficient in vitro model for cellular toxicology studies. In the current study, a protocol for culture of Prochilodus lineatus hepatocytes was established and utilized to investigate the cellular responses to purified cylindrospermopsin exposure. Hepatocytes were successfully dissociated with dispase, resulting in a cell yield of 6.36 × 10(7)cells g(-1) of liver, viability of 97% and attachment on uncoated culture flasks. For investigation of cylindrospermopsin effects, hepatocytes were dissociated, cultured during 96 h and exposed to three concentrations of the toxin (0.1, 1.0 or 10 µgl(-1)) for 72 h. Cylindrospermopsin exposure significantly decreased cell viability (0.1 and 1 µgl(-1)) and multixenobiotic resistance mechanism, MXR (all exposed groups), but increased reactive oxygen/nitrogen species levels (all exposed groups) and lipid peroxidation (10 µgl(-1)). On the other hand no significant alterations were observed for other biochemical biomarkers as 2GSH/GSSG ratio, protein carbonyl levels and DNA strand breaks or glutathione S-transferase and glucose 6-phosphate dehydrogenase activities. In conclusion, hepatocytes might be made sensitive to cylindrospermopsin, at least in part, due to reduction of xenobiotics and endobiotics efflux capacity by MXR. Additionally, the toxin exposure suggests important issues regarding hepatocytes survival at the lowest cylindrospermopsin concentrations.

Responses of hepatocytes to DDT and methyl mercury exposure.

The aim of the current work was to investigate the effects of dichlorodiphenyltrichloroethane (DDT) and monomethyl mercury (MeHg) on hepatocytes from tropical fish Hypostomus commersoni (cascudo). In order to verify DDT and MeHg impacts on the redox milieu, cells were exposed for 4 days to 50 nM of DDT, 0.25 and 2.5 microM of MeHg and to a combination of 50 nM of DDT and 0.25 microM of MeHg. These concentrations were compared with those previously published (Filipak Neto et al., 2008) for the predator fish Hoplias malabaricus (traíra). The effects were mostly noticeable on reduced glutathione concentration and delta-aminolevulinic acid dehydratase and glutathione S-transferase activity. Catalase activity increased in the group exposed to 2.5 microM of MeHg and hydrogen peroxide levels decreased in all exposed groups. Also, superoxide anion levels decreased in the groups exposed to 2.5 microM of MeHg and DDT *MeHg group. Cell viability decreased only in the DDT exposed group, demonstrating that the antioxidant defense mechanism of H. commersoni hepatocytes is more efficient than H. malabaricus. These results corroborate the resistance of H. commersoni to polluted areas and support the hypothesis that this species is more resistant to DDT and MeHg than H. malabaricus species.

Toxic effects of DDT and methyl mercury on the hepatocytes from Hoplias malabaricus.

Here, we examined the impact of dichlorodiphenyltrichloroethane (DDT) and monomethyl mercury (MeHg) on the redox milieu and survival of hepatocytes from Hoplias malabaricus (traíra). After isolation and attachment of cells, we established one control and four treatments: DDT (50nM of DDT), MeHg I (0.25microM of MeHg), MeHg II (2.5microM of MeHg) and DDT * MeHg I (combination of 50nM of DDT and 0.25microM of MeHg). After four days the exposed hepatocytes presented significantly increased damage in lipids (all treatments), proteins (DDT * MeHg I and MeHg II) and reduced cell viability (all treatments). Also the antioxidant enzymes catalase, glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase and superoxide dismutase were affected. The current data showed that despite of some protective responses, the increased disturbs on membrane lipids and proteins, increased hydrogen peroxide levels, and decreased glutathione concentration and cell viability strongly indicate oxidative stress as the reason of hepatotoxicity due to DDT and MeHg exposure. In addition, DDT and MeHg together had greater effect than alone when G6PDH and glutathione-S-transferase activities and lipids damage were considered. These findings are indicative of hepatotoxicity occurring at realistic concentrations of DDT and MeHg found in Amazonian fish tissues.

The immune response of peritoneal macrophages due to exposure to inorganic lead in the house mouse Mus musculus.

Peritoneal macrophages from the house mouse (Mus musculus) were exposed to variable lead (Pb) concentrations (0.2, 2, 20 and 40 microM) to better understand lead cytotoxicity and its damage to the immune response. Phagocytes were exposed to 20 and 40 microM Pb for 72 h, and macrophages were exposed at lower concentrations (0.2, 2 and 20 microM Pb) for 24h and 72 h. Dysfunctions in macrophage immune activity were examined by measuring phagocytic activity, nitric oxide production, endosomal/lysosomal stability and cell adhesion. Lead affected all macrophage functions, even at low concentrations, by reducing the phagocytic index, nitric oxide production, endosomal/lysosomal system stability and cell adhesion, and upregulating the antioxidant enzymatic activity of catalase. We demonstrate that lead affects the redox status of the cells and suggest that the immunomodulatory effects at low dosages on mouse macrophages reduces their ability to protect the host against infectious agents.

Use of hepatocytes from Hoplias malabaricus to characterize the toxicity of a complex mixture of lipophilic halogenated compounds.

Organisms are continuously exposed to a plethora of anthropogenic toxicants daily released to the environment. In the present study, the effects of a mixture of halogenated organic compounds (HOCs) extracted from hepatic lipids were evaluated on the primary hepatocyte culture from fish Hoplias malabaricus. Cells were isolated through non-enzymatic perfusion protocol and cultured during 3 days to allow attachment. Two concentrations of the mixture of HOCs (10 ng ml(-1) [Mix10] and 50 ng ml(-1) [Mix50]) were tested in cells for 2 days by medium replacement. The control groups, with and without solvent (DMSO) were run in the same conditions. Both tested concentrations of HOCs increased the catalase and GST activities, but only the Mix50 increase the DNA damage and decreased the GSH concentration and cell viability. Lipid peroxidation increased in the Mix10 group, but it seems to be more a consequence of DMSO presence than the HOCs themselves. The DMSO at 0.1% increased the lipid peroxidation, GSH concentration, apoptosis and DNA damage. The present data suggest that DMSO interferes with the hepatocytes of H. malabaricus in culture and that the mixture of HOCs tested alters the redox state of the hepatocytes.

Cell death and DNA damage in peritoneal macrophages of mice (Mus musculus) exposed to inorganic lead.

Lead is a heavy metal of considerable environmental and occupational concern and there is growing evidence that it is toxic to the human immune system. In this regard, this study examined the effect of lead (Pb) exposure to peritoneal macrophages (Mvarphis) of mice (Mus musculus) cultivated in DMEM medium supplemented with fetal bovine serum, in order to investigate cell damage related to cell death. Cells were exposed to two concentrations of inorganic lead [Pb(II)] for 4, 24 and 72h. Cell viability declined during the treatment, with responses including cell death, cellular damage and DNA damage. Cell death images were found in treated cells with an increase in Bax expression, but the inorganic lead failed to induce the loss of membrane asymmetry (Annexin V conjugates), suggesting that cell death was mainly due to necrosis induction. The effects of Pb(II) on the mechanisms of cell death is not completely understood, but the immunosuppression due to DNA damage and Mvarphis death is discussed here. We have previously shown the effect of inorganic lead in mitochondria and phagocytosis in Mvarphis, suggesting here a pathway for the effect of the metal on mechanisms of cell death, also discussing its effects on the immune system.

Hematological findings in neotropical fish Hoplias malabaricus exposed to subchronic and dietary doses of methylmercury, inorganic lead, and tributyltin chloride.

Hematological indices are gaining general acceptance as valuable tools in monitoring various aspects the health of fish exposed to contaminants. In this work some effects of methyl mercury (MeHg), inorganic lead (Pb2+), and tributyltin (TBT) in a tropical fish species were evaluated by hematological methods after a trophic exposition at a subchronic level. Forty-two mature individuals of the freshwater top predator fish Hoplias malabaricus were exposed to trophic doses (each 5 days) of MeHg (0.075 microg g(-1)), Pb2+ (21 microg g(-1)), and TBT (0.3 microg g(-1)) using young fish Astyanax sp. as prey vehicle. After 14 successive doses over 70 days, blood was sampled from exposed and control groups to evaluate hematological effects of metals on erythrocytes, total leukocytes and differential leukocytes counts, hematocrit, hemoglobin concentration, and red blood cell indices mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). Transmission electron microscopy and image analysis of erythrocytes were also used to investigate some morphometric parameters. Results show no significant effects in MCH and MCHC for all tested metals, but differences were found in erythrocytes, hemoglobin, hematocrit, MCV, and white blood cells counts. The number of leukocytes was increased in the presence of MeHg, suggesting effects on the immune system. Also the MCV increased in individuals exposed to MeHg. No ultrastructural damages were observed in red blood cells but the image analysis using light microscopy revealed differences in area, elongation, and roundness of erythrocytes from individuals exposed to Pb2+ and TBT but not in the group exposed to MeHg. The present work shows that changes in hematological and blood indices could highlight some barely detectable metal effects in fish after laboratory exposure to contaminated food, but their application in field biomonitoring using H. malabaricus will need more detailed studies and a careful consideration of environmental parameters.