Assessing the water quality in a World Heritage Site using biomarkers in top fish predators.

The use of biomarkers in fish for biomonitoring is a valuable approach to reveal effects of human impacts on biota health. Top predator fish are effective models for monitoring human activities' impacts on aquatic ecosystems. The Guaraguaçu River is the largest river-system on coastal region of South Brazil and a World Heritage site. The river receives contaminants from disorderly urban growth, including discharges of domestic sewage and small fishery boats, particularly during the tourist season. Our study aimed to assess impact of anthropogenic activities on water quality in the Guaraguaçu River by analyzing environmental contamination biomarkers in the top fish predator Hoplias malabaricus. Fish were collected using a fyke net trap across sectors representing a gradient of anthropic impact: sector 1 - pristine; sector 2 - impacted; and sector 3 - less impacted. Water samples were collected to analyze the presence of trace elements and pesticide. Biomarkers of the antioxidant system, histopathology, genotoxicity, neurotoxicity, and concentration of trace elements were analyzed in fish tissues. In water samples Al, Fe and Mn were detected, but no pesticides were found. In fish muscle, zinc and iron were detected. Brain acetylcholinesterase activity decreased in impacted sectors, indicating neurotoxic effects. The antioxidant system increased activity in gills and liver, and damage from lipoperoxidation was observed, particularly in sector 2 when compared to sector 1, suggesting oxidative stress. Histopathological biomarkers revealed lesions in the liver and gills of fish in impacted sectors. Micronuclei, a genotoxicity biomarker, were observed in organisms from all sectors. Our results demonstrate detrimental effects of poor water quality on biota health, even when contaminants are not detected in water.

Ecotoxicity of doped zinc oxide nanoparticles: Perspectives on environmental safety.

Studies on the ecotoxicity of doped zinc oxide nanoparticles (ZnO NPs) are recent, with the first publications starting in 2010. In this sense, this is the first study that comprehensively reviews the ecotoxicological effects of ZnO NPs doped with lanthanide elements to fill this literature gap. This research explores a multifaceted question at the intersection of nanotechnology, toxicology, and environmental science. Different types of dopants commonly used for ZnO doping were investigated in this review, focusing on the ecotoxicological effects of lanthanides as dopants. Bacteria were the main class of organisms used in ecotoxicological studies, since antimicrobial activity of these nanomaterials is extensively explored to combat the imminent problem of resistant bacteria, in addition to enabling the safe use of these nanomaterials for biomedical applications. Doping appears to exhibit greater efficacy when compared to undoped ZnO NPs in terms of antimicrobial effects; however, it cannot be said that it has no impact on non-target organisms. An extensive examination of the literature also establishes the importance and need to evaluate the effects of doped ZnO NPs on organisms from different environmental compartments in order to identify their potential impacts. We underscore the dearth of research information regarding the environmental toxicity/ecotoxicity of doped ZnO nanoparticles across various ecological levels, thereby limiting the extrapolation of findings to humans or other complex models. Therefore, we emphasize the urgency of a multi-parameter assessment for the development of sanitary and environmentally safe nanotechnologies.

Different response of females and males Neotropical catfish (Rhamdia quelen) upon short-term temperature increase.

Climate change has been one of the most discussed topics in the world. Global warming is characterized by an increase in global temperature, also in aquatic environments. The increased temperature can affect aquatic organisms with lethal and sublethal effects. Thus, it is necessary to understand how different species respond to temperature. This study aimed to evaluate how the Neotropical catfish species Rhamdia quelen responds to temperature increases. The fish were exposed to temperatures of 25 °C (control) and 30 °C after gradual temperature increase for 7 days. After 96 h in each temperature, the fish were anesthetized, blood was collected, and after euthanasia, brain, liver, posterior kidney, gills, muscle, and gonads were collected. The gonads were used for sexing, while other tissues were used for the hematological, biochemical, genotoxic, and histopathological biomarkers analysis. Hepatic proteomic analysis with a focus on energy production was also carried out. Blood parameter changes in both sexes, including an increase in glucose in males, leukopenia in females, and genotoxicity in both sexes. Hepatic proteins related to energy production were altered in both sexes, but mainly in males. Others biomarker alterations, such as histopathological, were not observed in other tissues; however, the antioxidant system was affected differently between sexes. These showed that R. quelen juveniles, at temperatures higher than its optimum temperature such as 30 °C, has several sublethal changes, such as hematological alterations, antioxidant system activation, and energetic metabolism alteration, especially in males. Thus, short-term temperature rise can affect females and males of R. quelen differently.

Prediction of acute fish toxicity (AFT) and fish embryo toxicity (FET) tests by cytotoxicity assays using liver and embryo zebrafish cell lines (ZFL and ZEM2S).

Fish cell-based assays represent potential alternative methods to vertebrates' use in ecotoxicology. In this study, we evaluated the cytotoxicity of thirteen chemicals, chosen from OECD guidelines 236 and 249, in two zebrafish cell lines (ZEM2S and ZFL). We aimed to investigate whether the IC50 values obtained by viability assays (alamar blue, MTT, CFDA-AM, and neutral red) can predict the LC50 values of Acute Fish Toxicity (AFT) test and Fish Embryo Toxicity (FET) test. There was no significant difference between the values obtained by the different viability assays. ZFL strongly correlated with AFT and FET tests (R2AFT = 0.73-0.90; R2FET48h = 0.79-0.90; R2FET96h = 0.76-0.87), while ZEM2S correlated better with the FET test (48h) (R2 = 0.70-0.86) and weakly with AFT and FET tests (96h) (R2AFT = 0.68-0.74 and R2FET96h = 0.62-0.64). The predicted LC50 values allowed the correct categorization of the chemicals in 76.9% (AFT test) - 90.9% (FET test) using ZFL and in 30.7% (AFT test) - 63.6% (FET test) using ZEM2S considering the US EPA criterion for classifying acute aquatic toxicity. ZFL is a promising cell line to be used in alternative methods to adult fish and fish embryos in ecotoxicity assessments, and the method performed in 96-well plates is advantageous in promoting high-throughput cytotoxicity assessment.

Evidence of genotoxicity, neurotoxicity, and antioxidant imbalance in silver catfish Rhamdia quelen after subchronic exposure to diisopentyl phthalate.

Diisopentyl phthalate (DiPeP) is a plasticizer with significant offer and application in Brazilian industries. This is attributed to its origin, which is closely linked to the refining process of sugarcane for ethanol production in the country. In this work, we developed a model for trophic exposure to environmentally relevant doses (5, 25, and 125 ng/g of DiPeP) to identify possible target tissues and toxic effects promoted by subchronic exposure to DiPeP in a Neotropical catfish species (Rhamdia quelen). After thirty days of exposure, blood, liver, kidney, brain, and muscle were collected and studied regarding DNA damage in blood cells and biochemical analyses. The kidney was the most affected organ, as in the head kidney, genotoxicity was evidenced in all groups exposed to DiPeP. Besides, the caudal kidney showed a reduction in the superoxide dismutase and glutathione peroxidase activities as well as a reduced glutathione concentration. In the liver, exposure to 125 ng/g of DiPeP increased glutathione S-transferase activity and reduced glutathione levels. In muscle, acetylcholinesterase (AChE) was reduced. However, in the brain, an increase in AChE activity was observed after the exposure to lowest doses. In contrast, a significant reduction of brain AChE activity after exposure to the highest dose was detected. The pronounced genotoxicity observed in head kidney cells is of concern, as it may compromise different functions performed by this organ (e.g., hematopoiesis, immune and endocrine functions). In our study, DiPeP proved to be a compound of environmental concern since we have evidenced its nephrotoxic and neurotoxic potential even in low doses.

Co-exposure effects of lead and TiO2 nanoparticles in primary kidney cell culture from the freshwater fish Hoplias malabaricus.

This study evaluated the effects of Lead (Pb) and titanium dioxide nanoparticles (TiO2 NPs) alone or in combination in anterior kidney macrophages of the freshwater fish Hoplias malabaricus, naïve or stimulated with 1 ng.mL-1 lipopolysaccharide (LPS). Pb (1 ×10-5 to 1 ×10-1 mg.mL-1) or TiO2 NPs (1.5 ×10-6 to 1.5 ×10-2 mg.mL-1) reduced cell viability despite LPS stimulation, especially Pb 10-1 mg.mL-1. In combination, lower concentrations of NPs intensified Pb-induced cell viability reduction while higher concentrations restored the cell viability independently of LPS stimulation. Basal and LPS- induced NO production was reduced by both TiO2 NPs and Pb isolated. The combination of both xenobiotics avoided this reduction of NO production by the isolated compounds at lower concentrations but the protective effect was lost as the concentrations increased. None xenobiotic increase DNA fragmentation. Therefore, at specific conditions, TiO2 NPs may have a protective effect over Pb toxicity, may also provide additional toxicity at higher concentrations.

Experimentally exposed toxic effects of long-term exposure to environmentally relevant concentrations of CIP in males and females of the silver catfish Rhamdia quelen.

Ciprofloxacin (CIP) is an antibiotic commonly used in human and veterinary medicine. It is present in the aquatic environment, but we still know very little about its effect on non-targeted organisms. This study aimed to evaluate the effects of long-term exposure to environmental CIP concentrations (1, 10, and 100 µg.L-1) in males and females of Rhamdia quelen. After 28 days of exposure, we collected the blood for the analysis of hematological and genotoxic biomarkers. Additionally, we measured 17 ß-estradiol and 11 keto-testosterone levels. After the euthanasia, we collected the brain and the hypothalamus to analyze acetylcholinesterase (AChE) activity and neurotransmitters, respectively. The liver and gonads were assessed for biochemical, genotoxic, and histopathological biomarkers. At 100 µg.L-1 CIP, we observed genotoxicity in the blood, nuclear morphological changes, apoptosis, leukopenia, and a reduction of AChE in the brain. In the liver was observed oxidative stress and apoptosis. At 10 µg.L-1 CIP, leukopenia, morphological changes, and apoptosis were presented in the blood and a reduction of AChE in the brain. Apoptosis, leukocyte infiltration, steatosis, and necrosis occurred in the liver. Even at the lowest concentration (1 µg.L-1), adverse effects such as erythrocyte and liver genotoxicity, hepatocyte apoptosis, oxidative stress, and a decrease in somatic indexes were observed. The results showed the importance of monitoring CIP concentrations in the aquatic environment that cause sublethal effects on fish.

A 3D Culture Method of Spheroids of Embryonic and Liver Zebrafish Cell Lines.

Fish cell lines are promising in vitro models for ecotoxicity assessment; however, conventional monolayer culture systems (2D culture) have well-known limitations (e.g., culture longevity and maintenance of some in vivo cellular functions). Thus, 3D cultures, such as spheroids, have been proposed, since these models can reproduce tissue-like structures, better recapturing the in vivo conditions. This article describes an effective, easy, and fast 3D culture protocol for the formation of spheroids with two zebrafish (Danio rerio) cell lines: ZEM2S (embryo) and ZFL (normal hepatocyte). The protocol consists of plating the cells in a round-bottom, ultra-low attachment, 96-well plate. After 5 days under orbital shaking (70 rpm), a single spheroid per well is formed. The formed spheroids present stable size and shape, and this method avoids the formation of multiple spheroids in a well; thus, it is not necessary to handpick spheroids of similar sizes. The ease, speed, and reproducibility of this spheroid method make it useful for high-throughput in vitro tests.

Salvinia molesta phytoremediation capacity as a nature-based solution to prevent harmful effects and accumulation of ciprofloxacin in Neotropical catfish.

Phytoremediation has been a potential solution for the removal of pharmaceuticals from water. Here, we evaluated the toxicological safety of ciprofloxacin-contaminated water treated by 96 h with Salvinia molesta. The Neotropical catfish Rhamdia quelen was used as a model, and the potential of the phytoremediation technique for mitigating the drug accumulation in the fishes was also studied. Fish exposed to Cipro (1 and 10 µg·L-1) in untreated water showed toxic responses (alteration of hematological, genotoxicity, biochemical, and histopathological biomarkers) and accumulated Cipro in their muscles at concentrations high for human consumption (target hazardous quotient > 1). Fish exposed to water treated with S. molesta showed no toxic effect and no accumulation of Cipro in their tissues. This must be related to the fact that S. molesta removed up to 97% of Cipro from the water. The decrease in Cipro concentrations after water treatment with S. molesta not only prevented the toxic effects of Cipro on R. quelen fish but also prevented the antimicrobial accumulation in fish flesh, favouring safe consumption by humans. For the very first time, we showed the potential of phytoremediation as an efficiently nature-based solution to prevent environmental toxicological effects of antimicrobials to nontarget organisms such as fish and humans. The use of S. molesta for Cipro-removal from water is a green technology to be considered in the combat against antimicrobial resistance.

Sublethal effects of the herbicides atrazine and glyphosate at environmentally relevant concentrations on South American catfish (Rhamdia quelen) embryos.

The objective of this work was to evaluate the effects following exposure (96 h) of South American catfish (R. quelen) embryos to active ingredients and commercial formulations from atrazine and glyphosate, isolated and in mixtures, at environmentally relevant concentrations. While the survival rates were not affected, sublethal effects were evidenced after exposure. The most frequent deformities were fin damage and axial and thoracic damage. The mixture of active ingredients caused an increase in SOD and GST, differing from the treatment with the mixture of commercial formulations. The activity of AChE was significantly reduced following the treatment with the active ingredient atrazine and in the mixture of active ingredients. In general, herbicide mixtures were responsible for causing more toxic effects to R. quelen embryos. Therefore, these responses showed to be suitable biomarkers of herbicides' exposure, in addition to generating more environmentally relevant baseline data for re-stablishing safety levels of these substances in aquatic bodies.

Cytotoxicity Assays with Zebrafish Cell Lines.

Fish cell lines have become increasingly used in ecotoxicity studies, and cytotoxicity assays have been proposed as methods to predict fish acute toxicity. Thus, this protocol presents cytotoxicity assays modified to evaluate cell viability in zebrafish (Danio rerio) embryo (ZEM2S) and liver (ZFL) cell lines in 96-well plates. The cytotoxicity endpoints evaluated are mitochondrial integrity (Alamar Blue [AB] and MTT assays), membrane integrity via esterase activity (CFDA-AM assay), and lysosomal membrane integrity (Neutral Red [NR] assay). After the exposure of the test substances in a 96-well plate, the cytotoxicity assays are performed; here, AB and CFDA-AM are carried out simultaneously, followed by NR on the same plate, while the MTT assay is performed on a separate plate. The readouts for these assays are taken by fluorescence for AB and CFDA-AM, and absorbance for MTT and NR. The cytotoxicity assays performed with these fish cell lines can be used to study the acute toxicity of chemical substances on fish.

Alkylphenols cause cytotoxicity and genotoxicity induced by oxidative stress in RTG-2 cell line.

Alkylphenols ethoxylates are industrial surfactants, and the release in the environmental matrices produces degraded products, of which nonylphenol (NP) and octylphenol (OP) were the most common. They can be classified as endocrine disruptors since the estrogenic potential is widely recognized, but some others toxic aspects are in discussion. This study aimed to evaluate the toxicity of NP, OP, and mixtures of both through cellular, biochemical and genetic biomarkers in fish gonadal cell line RTG-2 exposed to nominal concentrations of 0.05; 0.5; 5; 50, and 100 µg mL-1 of each chemical and their mixtures of 0.05, 0.5; 5 µg mL-1 concentrations. After 24 h, the cells were collected for cytotoxic (neutral red - NR; crystal violet - CV, resazurin assay - RA and lactate-dehydrogenase - LDH), antioxidant system (glutathione-s-transferase - GST; superoxide-dismutase - SOD; glutathione-peroxidase - GPx and malondialdehyde - MDA) and genotoxic assays (alkaline comet assay and Fpg-modified alkaline comet assay). The chemicals and their mixtures were cytotoxic at 50 and 100 µg mL-1, in general aspect, but LDH showed cytotoxicity since 0.05 µg mL-1. The GST and SOD showed an activity increase trend in most tested groups, while GPx decreased at 5 µg mL-1 of the mixture. The MDA increase in all groups resulted in lipid peroxidation. The reactive oxygen species caused DNA damage for all groups. The tested chemicals and concentrations have been found in the freshwater systems. They can induce cell toxicity in several parameters that could impair the gonadal tissues considering the RTG-2 responses.

Evaluation of the toxicity of di-iso-pentyl-phthalate (DiPeP) using the fish Danio rerio as an experimental model.

The presence of phthalates constitutes a risk to the health of aquatic environments and organisms. This work aimed to evaluate the toxic effects of di-iso-pentyl-phthalate (DiPeP) at environmentally relevant concentrations of 5, 25, and 125 µg/L in Danio rerio after subchronic exposure for 14 days. DiPeP altered the antioxidant system in the liver (125 µg/L), intestine (25 µg/L), brain, and gills in all concentrations tested. In animals exposed to 125 µg/L, DNA damage was identified in the gills. In addition, loss of cell boundary of hepatocytes, vascular congestion, necrosis in the liver, and presence of immune cells in the intestinal lumen were observed. Erythrocytic nuclear alterations in the blood occurred in animals exposed to 25 µg/L. DiPeP was quantified in muscle tissue at all exposure concentrations, appearing in a concentration-dependent manner. Contaminants such as DiPeP will still be used for a long time, mainly by industries, being a challenge for industry versus environmental health.

In vitro evaluation of the inhalation toxicity of the cosmetic ingredient aluminum chlorohydrate.

Aluminum chlorohydrate (ACH) is a major aerosol component frequently used as the active ingredient in antiperspirants, and in vivo studies have raised a concern about its inhalation toxicity. Still, few studies have addressed its effects on the human respiratory tract. Therefore, we developed a study on ACH inhalation toxicity using an in vitro human alveolar cell model (A549 cells) with molecular and cellular markers of oxidative stress, immunotoxicity, and epigenetic changes. The chemical characterization of ACH suspensions indicated particle instability and aggregation; however, side-scatter analysis demonstrated significant particle uptake in cells exposed to ACH. Exposure of A549 cells to non-cytotoxic concentrations of ACH (0.25, 0.5, and 1 mg/ml) showed that ACH induced reactive oxygen species. Moreover, ACH upregulated TNF, IL6, IL8, and IL1A genes, but not the lncRNAs NEAT1 and MALAT1. Finally, no alterations on the global DNA methylation pattern (5-methylcytosine and 5-hydroxymethylcytosine) or the phosphorylation of histone H2AX (γ-H2AX) were observed. Our data suggest that ACH may induce oxidative stress and inflammation on alveolar cells, and A549 cells may be useful to identify cellular and molecular events that may be associated with adverse effects on the lungs. Still, further research is needed to ensure the inhalation safety of ACH.

Protective potential of sulfated polysaccharides from tropical seaweeds against alkylating- and oxidizing-induced genotoxicity.

Sulfated polysaccharides (SPs) from seaweeds are potential bioactive natural compounds, but their DNA protective activity is poorly explored. This article aimed to evaluate the genotoxic/antigenotoxic potentials of a sulfated heterofucan from brown seaweed Spatoglossum schröederi (Fucan A - FA) and a sulfated galactan from green seaweed Codium isthomocladum (3G4S) using in vitro Comet assay (alkaline and oxidative versions) with HepG2 cells. The antioxidant activity of these SPs was evaluated by total antioxidant capacity, radical scavenging, metal chelating, and antioxidant enzyme activity assays. Both SPs were not genotoxic. FA and 3G4S displayed strong antigenotoxic activity against oxidizing chemical (H2O2) but not against alkylating chemical (MMS). The DNA damage reduction after a pre-treatment of 72 h with these SPs was 81.42% to FA and 81.38% to 3G4S. In simultaneous exposure to FA or 3G4S with H2O2, HepG2 cells presented 48.04% and 55.41% of DNA damage reduction compared with the control, respectively. The antigenotoxicity of these SPs relates to direct antioxidant activity by blockage of the initiation step of the oxidative chain reaction. Therefore, we conclude that FA and 3G4S could be explored as functional natural compounds with antigenotoxic activity due to their great protection against oxidative DNA damage.

High Melanin Content in Melanoma Cells Contributes to Enhanced DNA Damage after Rose Bengal Photosensitization.

Melanoma is a type of tumor that originates from melanocytes. Irradiation of melanin with UVA and visible light can produce reactive oxygen species (ROS) such as singlet molecular oxygen (1 O2 ). The objective of this study was to examine DNA damage in melanoma cells (B16-F10) with different melanin contents, subjected to 1 O2 generation. To this end, we used the photosensitizer Rose Bengal acetate (RBAc) and irradiation with visible light (526 nm) (RBAc-PDT). We used the modified comet assay with the repair enzymes hOGG1 and T4 endonuclease V to detect the DNA damage associated with 8-oxo-7,8-dihydro-2'-deoxyguanosine and cyclobutane pyrimidine dimers lesions, respectively. We observed increased formation of hOGG1- and T4endoV-sensitive DNA lesions after light exposure (with or without RBAc). Furthermore, 18 h after irradiation, hOGG1-sensitive DNA lesions increased compared to that at the initial time point (0 h), which shows that a high melanin content contributes to post-irradiation formation of them, mainly via sustained oxidative stress, as confirmed by the measurement of ROS levels and activity of antioxidant enzymes. Contrastingly, the number of T4endoV-sensitive DNA lesions decreased over time (18 h). Our data indicate that in melanoma cells, a higher amount of melanin may affect DNA damage levels when subjected to RBAc-PDT.

Sublethal biochemical, histopathological and genotoxicological effects of short-term exposure to ciprofloxacin in catfish Rhamdia quelen.

Ciprofloxacin (Cipro) is commonly detected in water worldwide, however, the ecotoxicological effects to aquatic biota is still not fully understood. In this study, using multiple biomarkers, it was investigated sublethal effects of short-term exposure to Cipro concentrations (1, 10 and 100 µg.L-1) in the Neotropical catfish Rhamdia quelen compared to non-exposure treatment (Control). After 96 h of exposure, the fishes were anesthetized for blood collection to hematological and genotoxicity biomarkers analysis. After euthanasia, the brain and muscle were sampled for biochemical biomarkers analyses. Gills, liver and posterior kidney for genotoxicity, biochemical and histopathological biomarkers analysis and anterior intestine for histopathological biomarkers analysis. Genotoxicity was observed in all tissues, regardless of the Cipro concentrations. Hematological alterations, such as reduction of the number of erythrocytes and leucocytes, as well as in hematocrit concentration and histopathological damages, such as reduction of microridges in gill epithelium and necrosis in liver and posterior kidney, occurred mainly at 100 µg.L-1. In addition, at 100 µg.L-1, Cipro increased antioxidant system activity (Catalase in liver and posterior kidney). These results demonstrated that under short-term exposure, Cipro causes toxic effects in R. quelen that demands attention and surveillance of environmental aquatic concentrations of this antibiotic.

Effects of cadmium on the female reproductive axis of a Neotropical fish.

Metals are one of the contaminants released from the increase of anthropic activities. They can be classified as endocrine disruptors once they can affect the reproductive parameters of different organisms. The aim of the study was to evaluate the potential effects of cadmium on regulatory reproduction axis (Hypothalamic-Pituitary-Gonadal-Liver, the HPGL axis) in females of Rhamdia quelen exposed to nominal concentrations of 0.1; 1; 10 and 100 µg.L-1 of cadmium. After 15 days, tissues were collected for hormonal quantification, brain aromatase (cyp19a1b), hepatic vitellogenin (vtg) gene expression, and biomarkers analysis. Cadmium was quantified in water, gonad and liver samples. The plasma levels of estradiol, testosterone and gonad and hepatosomatic indexes did not changed after Cd exposure. The cyp19a1b was not different among the groups. Cadmium was detected at higher concentrations in the liver compared to the gonads. No genotoxicity was observed, only erythrocytes nuclear alterations. Metallothionein was reduced at 10 µg.L-1 in the liver and 10 and 100 µg.L-1 in the gonad. Hepatic superoxide dismutase activity increased and this can lead to a hydrogen peroxide increase, one of reactive oxygen species. This increase without a compensation of other enzymes of the antioxidant system can lead to lipoperoxidation, as occurred at 100 µg.L-1. Hepatic vitellogenin gene expression increased as well as the injury index at 0,1 and 100 µg.L-1. The tested cadmium concentrations have been found in the freshwater ecosystems and can affect the female reproductive regulation axis HPGL of the Neotropical species R. quelen.

A biocide delivery system composed of nanosilica loaded with neem oil is effective in reducing plant toxicity of this biocide.

One possible way to reduce the environmental impacts of pesticides is by nanostructuring biocides in nanocarriers because this promotes high and localized biocidal activity and can avoid toxicity to non-target organisms. Neem oil (NO) is a natural pesticide with toxicity concerns to plants, fish, and other organisms. Thus, loading NO in a safe nanocarrier can contribute to minimizing its toxicity. For this study, we have characterized the integrity of a nanosilica-neem oil-based biocide delivery system (SiO2NP#NO BDS) and evaluated its effectiveness in reducing NO toxicity by the Allium cepa test. NO, mainly consisted of unsaturated fatty acids, was well binded to the SiO2NP with BTCA crosslinker. Overall, this material presented all of its pores filled with the NO with fatty acid groups at both the surface and bulk level of the nanoparticle. The thermal stability of NO was enhanced after synthesis, and the NO was released as zero-order model with a total of 20 days without burst release. The SiO2NP#NO BDS was effective in reducing the individual toxicity of NO to the plant system. NO in single form inhibited the seed germination of A. cepa (EC50 of 0.38 g L-1), and the effect was no longer observed at the BDS condition. Contrarily to the literature, the tested NO did not present cyto- and geno-toxic effects in A. cepa, which may relate to the concentration level and composition.

Effects on reproductive, biochemical and genotoxic parameters of herbicides 2,4-D and glyphosate in silver catfish (Rhamdia quelen).

The objective of this work was to evaluate the effects of the herbicides 2,4-D, glyphosate and the mixture of both on oxidative stress, genotoxicity and the rates of fertilization, hatching and larval normality in silver catfish. Exposure to glyphosate and the mixture of herbicides significantly decreased the fertilization of oocytes and the hatching of eggs. The different concentrations of 2,4-D and glyphosate, in addition to the mixture of both, did not affect the rates of larval normality, the activity of CAT, GST, LPO, and PCO. SOD activity was not evident in any of the treatments. Exposure to 2,4-D and the mixture of herbicides caused damage to the genetic material of larvae silver catfish. Our results show that although high concentrations of the herbicides were used, changes caused by them were detected in only some of the tested biomarkers.