Acute Exposure to Biogenic Nanosilver Produced from Fusarium oxysporum in a Neotropical Fish

Biogenic nanosilver (bNAg) has emerged as a potentially less toxic alternative to synthetic nanosilver. However, no studies have evaluated its effects on a fish species from the Neotropical region. Thus, our aim was to evaluate the effects of a bNAg on the Neotropical fish Prochilodus lineatus. For this purpose, after 24 h of exposure to 100 µg L^-1 of bNAg, blood samples were collected to evaluate hematological, genotoxic, and plasma parameters. Gills and liver were sampled to evaluate biomarkers of oxidative stress and brain samples were used to assess neurotoxicity. The fish presented hyperglycemia, an increased number of erythrocytes, a reduction in antioxidant enzyme activity in both tissues evaluated, and a decrease in lipid peroxidation in the gills. We concluded that P. lineatus is a sensitive species to this nanoparticle, since it presented alterations in several biomarkers after an acute exposure.

Interference of goethite in the effects of glyphosate and Roundup® on ZFL cell line

Goethite (α-FeOOH) brings important perspectives in environmental remediation, as, due to its physicochemical properties, this iron oxide can adsorb a wide variety of compounds, including glyphosate. This study aimed to evaluate the effects of goethite nanoparticles (NPs), glyphosate (Gly), Roundup® (Rd), and co-exposures (Gly + NPs and Rd + NPs) on zebrafish liver cell line (ZFL). ZFL cells were exposed to NPs (1, 10, and 100 mg L-1), Gly (3.6 mg L-1), Rd (10 mg L-1), and co-exposures (Gly + NPs and Rd + NPs), or only to saline for 1, 6, and 12 h. Cell viability was assessed by Trypan blue, MTT, and neutral red assays. The generation of reactive oxygen species and total antioxidant capacity were also determined, while genotoxicity was quantified by the comet assay. Both NPs and Rd in isolation produced cytotoxic effects at 6 h and genotoxic effects at 1 and 6 h. Rd + NPs resulted in synergistic effects, intensifying the toxicity. Cells exposed to Gly did not present toxic effects and Gly + NPs resulted in the suppression of toxic effects observed for NPs. The presence of other components in Roundup® seems to favor its toxicity compared to the active ingredient. In conclusion, according to the in vitro model, the concentrations used were not safe for the ZFL lineage.

Chromium accumulation and biomarker responses in the Neotropical fish Prochilodus lineatus caged in a river under the influence of tannery activities

In order to assess the effects of tannery effluents (TE) in organism health, juveniles of Prochilodus lineatus were submitted to in situ tests at four different river locations: site A - upstream of the tannery; site B - next to the tannery; and sites C and D - downstream of the tannery. After 96 h exposure in the river, samples of fish tissue, river water and sediment were collected in order to quantify chromium (Cr) concentrations. Tissue samples were used to assess the activity of ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST), the content of glutathione (GSH) and metallothionein (MT) and the occurrence of lipid peroxidation (LPO) and DNA damage. Higher Cr concentrations were detected in the water and sediments from site B and in the liver of fish confined at site B, compared to the other sites. Fish caged at site B demonstrated higher levels of liver MT and hepatic EROD activity in relation to fish caged at the other sites. Moreover, fish from site B presented increased liver and branchial GST activities, as well as more GSH in the liver, than fish from site A. There were no significant variations in the occurrence of LPO and DNA damage among fish caged at the different sites. Thus, TE increased Cr levels in the water, sediments, and fish livers and stimulated the synthesis of MT and GSH and the activities of EROD and GST. In conclusion, TE affect the quality of the river and promote changes in biochemical biomarkers and Cr accumulation in P. lineatus.

Bioaccumulation of nickel and its biochemical and genotoxic effects on juveniles of the neotropical fish Prochilodus lineatus

Juveniles of the freshwater fish Prochilodus lineatus were exposed to three concentrations of nickel (Ni): 25, 250 and 2500 µg L(-1) or water only for periods of 24 and 96 h to test for Ni bioaccumulation, its effects on antioxidant defenses and metallothioneins, and the occurrence of DNA damage. After exposure, the fish were sampled and tissue removed from the gills, liver, kidney and muscle to test for Ni accumulation and conduct biochemical (gills and liver) and genotoxic (blood cells and gills) analyses. The results showed that Ni accumulates in the organs in different proportions (kidney>liver>gills>muscle) and accumulation varied according to exposure time. Metallothionein (MT) levels increased in the liver and gills after exposure to Ni, implying that the presence of Ni in these tissues could induce MT synthesis. We also observed that Ni exposure affected antioxidant defenses, increasing lipid peroxidation in the liver of fish exposed to Ni for 96 h at the highest concentration tested. DNA damage increased in both blood cells and gills of fish exposed to all Ni concentrations, indicating the genotoxic potential of Ni on fish. We therefore concluded that Ni accumulates in various tissues and results in oxidative and DNA damage in P. lineatus, and that the maximum permitted Ni concentration set in Brazilian legislation (25 µg L(-1)) for freshwaters is not safe for this species.

Antinociceptive and acute toxicity evaluation of Vernonia condensata Baker leaves extracted with different solvents and their mixtures

Extract of Vernonia condensata (Asteraceae = Compositae) leaves has different uses in Brazilian folk medicine, which includes analgesic and antiinflamatory agent. The aim of this study was to apply a modified simplex-centroid mixture design to evaluate the best extractor system for the antinociceptive activity, evaluated by writhing test. Different solvents (acetone, dichloromethane, ethanol and ethyl acetate) as well as their binary, ternary and quaternary mixtures were used. For comparison, aqueous extract was also evaluated. LD50 was estimated and qualitative phytochemical screening, conducted. The extracts with antinociceptive activity were: aqueous, acetone, dicloromethane (DCM), ethanol (ETOH), acetone-DCM, acetone-ETOH, acetone-ethyl acetate, ETOH-ethyl acetate, acetone-DCM-ethyl acetate, acetone-ETOH-ethyl acetate and DCM-ETOH-ethyl acetate. The higher margin of safety (LD50/ED50) was for acetone > acetone-ETOH-ethyl acetate > aqueous > ETOH = acetone-ETOH > DCM > acetone-ethyl acetate > DCM-ETOH-ethyl acetate > acetone-DCM > acetone-DCM-ethyl acetate. Phytochemical screening showed that all the extracts contained alkaloids, phenolic compounds, flavonoids, tannins and saponins. In conclusion, the extractor system influences both the pharmacological activity and acute toxicity of leaves from V. condensata. Acetone and the ternary mixture, acetone-ETOH-ethyl acetate extracts showed higher margin of safety than aqueous extract.