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1.
Sci Total Environ ; 747: 141546, 2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-32795811

RESUMO

Previous studies have shown that the toxicity of graphene nanomaterials (GNMs) to bacteria are related to the surface functionalization, however, the involved mechanisms are not fully understood. The present study aims to explore the toxic mechanisms of differentially functionalized GNMs to bacteria from the aspects of physical interaction, oxidative damage and cell autolysis. Three basic functionalization of GNMs including carboxylation (G-COOH), hydroxylation (G-OH) and amination (G-NH2) were studied. G-COOH (66% viability vs CT group) and G-OH (54%) graphene showed higher toxicity to E. coli than G-NH2 (96%) within 3 h at a concentration of 50 mg/L. The three materials showed distinct physical interaction modes with bacterial cells. G-COOH and G-OH contact with cell membrane via their sharp edges thus causing more damage than G-NH2 which covered the bacteria attaching along the basal plane. The three GNMs showed similar radical generation capacities, thus the direct generation of radicals is not the mechanism causing the toxicity. Instead, the GNMs can oxidize the cellular antioxidant glutathione (GSH) thereby causing oxidative damage. The oxidative capacity follows the order: G-COOH > G-OH > G-NH2, which correlated with the antibacterial activity. Cell autolysis, the degradation of cell wall component peptidoglycan, was found to be a new mechanism inducing the death of bacteria. G-COOH and G-OH caused more cell autolysis than G-NH2, which accounts partially for the different toxicity of the three GNMs. The findings provide significant insights into the mechanism of GNMs toxicity to bacteria for not only the risk assessment of GNMs but also the design of graphene based antibacterial materials.


Assuntos
Grafite , Nanoestruturas , Escherichia coli , Grafite/toxicidade , Oxirredução , Estresse Oxidativo
2.
Ecotoxicol Environ Saf ; 205: 111102, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32836152

RESUMO

The increased production and environmental release of graphene nanoparticles has raised concerns about its environmental impact, but the effects of graphene on living organisms at the metabolic level remain unknown. In this study, we used matrix assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI)-based untargeted metabolomics to investigate the metabolic response of juvenile earthworms (Eisenia fetida) to graphene exposure in soil tests for the first time. Our results reveal that graphene-exposure significantly disturbs earthworm metabolome, and graphene toxicity on earthworm shows non-concentration-dependent effect. Alanine, phenylalanine, proline, glutamate, arginine, histidine, maltose, glucose, malate, succinate, myo-inositol, and spermidine were successfully screened as significantly change compounds in earthworms for the exposure of graphene. The heterogeneous distributions of these metabolites in earthworm were also clearly imaged by MALDI-MSI. Our MSI results fully showed that the metabolite expression levels in juvenile earthworms significantly changed (up-/down-regulation) after exposure to graphene nanoparticles. This work improves our understanding of graphene nanoparticle toxicity to juvenile earthworms and also enables the continued progression of MALDI-MSI-based metabolomics as an emerging, reliable, and rapid ecotoxicological tool for assessing contaminant toxicity.


Assuntos
Grafite/toxicidade , Oligoquetos/fisiologia , Poluentes do Solo/toxicidade , Alanina/metabolismo , Animais , Grafite/metabolismo , Metaboloma/efeitos dos fármacos , Metabolômica/métodos , Oligoquetos/efeitos dos fármacos , Solo/química , Poluentes do Solo/análise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
3.
Life Sci ; 257: 118062, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32652138

RESUMO

AIMS: In this study, for the first time, the effect of quercetin (Q) on the characteristic properties, antimicrobial activity, and cell viability of polycaprolactone (PCL)/graphene oxide (GO) electrospun scaffold was investigated. MAIN METHODS: Quercetin loaded graphene oxide nanoparticles have been incorporated into the poly-caprolactone solution, and their mixture has been electrospun to be applied as a nanofibrous scaffold for wound dressing and tissue engineering applications. The properties of scaffolds, like their morphology, tensile strength, hydrophilicity, and in vitro biological performance, are investigated. KEY FINDINGS: The SEM micrographs reveal the uniform bead-free nanofibers with smooth structures have been successfully fabricated via the electrospinning procedure. The overall average of cell viability of NIH/3 T3 fibroblast cells on scaffolds is 95% that means the scaffolds have no toxicity, and FESEM shows cells attach and proliferate on scaffolds. Moreover, among all the fabricated scaffolds, the maximum release of quercetin belongs to PCL/GO/Q 0.5 with about 70% after 15 days, and this scaffold reduces bacterial growth by about 50% after 12 h shows the excellent effect of GO/Q on the antibacterial activity of PCL nanofibers. SIGNIFICANCE: The results confirm that more than 1% of GO has some cytotoxicity, which limits its concentration; therefore, a second antibacterial agent is essential to improve the antibacterial activity of PCL/GO scaffold, and quercetin shows that it is an excellent candidate for this purpose.


Assuntos
Grafite/farmacologia , Poliésteres/química , Quercetina/farmacologia , Tecidos Suporte , Animais , Antibacterianos/administração & dosagem , Antibacterianos/farmacologia , Bandagens , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Grafite/administração & dosagem , Grafite/toxicidade , Camundongos , Células NIH 3T3 , Nanofibras , Quercetina/administração & dosagem , Engenharia Tecidual
4.
Chemosphere ; 259: 127221, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32615454

RESUMO

Due to its unique properties, graphene oxide (GO) has potential for biomedical and electronic applications, however environmental contamination including aquatic ecosystem is inevitable. Moreover, potential risks of GO in aquatic life are inadequately explored. Present study was designed to evaluate GO as an endocrine disrupting chemical (EDC) using the model Japanese medaka (Oryzias latipes). GO was injected intraperitoneally (25-200 µg/g) once to breeding pairs and continued pair breeding an additional 21 days. Eggs laid were analyzed for fecundity and the fertilized eggs were evaluated for developmental abnormalities including hatching. Histopathological evaluation of gonads, liver, and kidneys was made 21 days post-injection. LD50 was found to be sex-dependent. Fecundity tended to reduce in a dose-dependent manner during early post-injection days; however, the overall evaluation showed no significant difference. The hatchability of embryos was reduced significantly in the 200 µg/g group; edema (yolk and cardiovascular) and embryo-mortality remained unaltered. Histopathological assessment identified black particles, probably agglomerated GO, in the gonads of GO-treated fish. However, folliculogenesis in stromal compartments of ovary and the composition of germinal elements in testis remained almost unaltered. Moreover, granulosa and Leydig cells morphology did not indicate any significant EDC-related effects. Although liver and kidney histopathology did not show GO as an EDC, some GO-treated fish accumulated proteinaceous fluid in hepatic vessels and induced hyperplasia in interstitial lymphoid cells (HIL) located in kidneys. GO agglomerated in medaka gonads after 21-days post-injection. However, gonad histopathology including granulosa and Leydig cells alterations were associated with GO toxicity rather than EDC effects.


Assuntos
Grafite/toxicidade , Oryzias/fisiologia , Reprodução/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Ecossistema , Disruptores Endócrinos/toxicidade , Feminino , Fertilidade/efeitos dos fármacos , Gônadas/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Ovário/efeitos dos fármacos , Testículo/efeitos dos fármacos
5.
Ecotoxicol Environ Saf ; 199: 110639, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32408033

RESUMO

Graphene Oxide (GO) has wide applications in many fields which has caused a large expected quantity of the graphene-based wastes. It is necessary to understand the toxic effects of the GO on the activated sludge (AS) considering its inevitable discharge to the wastewater treatment plants as the ultimate repositories for these wastes. In this study, the acute exposures of the multilayer Nano-graphene oxide (MNGO) at different dosages were conducted in order to investigate its integrated effects on the formation of the biofilm, mature biofilm and the microbial activity of the activated sludge. Raman spectroscopy and laser scanning confocal microscopy (LSCM) were adopted for the in-situ characterization of the biofilm with the exposure of the MNGO. The results showed that the activated sludge was tolerable to the acute exposure of the less than 100 mg/L of the MNGO, especially for the mature biofilm, and only a subtle decrease was found in the size and thickness during the formation of the biofilm, while the amount of 300 mg/L of the MNGO caused the sever deterioration on the activated sludge system. The microbial metabolic activity, viability, and the biological removal of the nutrients were significantly affected with the more than 100 mg/L of the MNGO. It was also demonstrated by the microbial cytotoxicity tests that the increase in the exposure of the MNGO was related to the increase in the reactive oxygen species (ROS) and the damaging degree of the cell membrane.


Assuntos
Biofilmes/efeitos dos fármacos , Grafite/toxicidade , Viabilidade Microbiana/efeitos dos fármacos , Esgotos/microbiologia , Águas Residuárias/microbiologia , Poluentes Químicos da Água/toxicidade , China , Espécies Reativas de Oxigênio/metabolismo , Esgotos/química , Águas Residuárias/química , Purificação da Água/métodos
6.
Ecotoxicol Environ Saf ; 199: 110714, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32446100

RESUMO

Previous studies focused on biocompatibility of graphene oxide (GO) to macrophages, but the impact of GO on lipid profiles in macrophages was less investigated. Herein, we investigated the interactions between THP-1 macrophages and GO of different sizes (GO of size 500-5000 nm, denoted as GO-L; GO of size < 500 nm, denoted as GO-S). We found that after 24 h exposure, the internalization of GO appeared to be minimal, whereas up to 50 µg/mL of GO-L but not GO-S reduced lipid accumulation, accompanying with a significantly reduced release of soluble monocyte chemoattractant protein-1 (MCP-1) but not interleukin-6 (IL-6). Moreover, lipidomic data showed that GO-L decreased the levels of 17 lipid classes, whereas GO-S only decreased the levels of 5 lipid classes. For comparison, 50 µg/mL carbon black (CB) significantly increased lipid accumulation with considerable particle internalization. GO-reduced lipid accumulation was not related with increase of reactive oxygen species (ROS) or induction of autophagy, and modulation of autophagy by chemicals showed no significant effect to alter the effects of GO-L on lipid accumulation. However, exposure to GO reduced the mRNA and protein levels of key components in peroxisome proliferators-activated receptor (PPAR) signaling pathway, a pathway that is related with lipid droplet biogenesis, and the modulation of PPARγ by chemicals altered the effects of GO-L on lipid accumulation. In conclusion, our results suggested that GO size-dependently altered lipid profiles in THP-1 macrophages that might be related with PPAR signaling pathway.


Assuntos
Grafite/química , Grafite/toxicidade , Metabolismo dos Lipídeos/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Quimiocina CCL2/metabolismo , Humanos , Macrófagos/metabolismo , Macrófagos/patologia , PPAR gama/metabolismo , Tamanho da Partícula , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Células THP-1
7.
Bull Environ Contam Toxicol ; 105(1): 139-145, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32458034

RESUMO

In this study, the responses of wheat seedlings to graphene oxide (GO) were investigated at a wide concentration range of 0-1000 mg L-1, including oxidative stress, real-time membrane potential as well as proton and calcium ion fluxes. The results show that GO induced a hormesis effect on root growth (low concentration (100 mg L-1) promotion and high concentration (1000 mg L-1) inhibition. Oxidative stress was responsible for the growth inhibition at GO concentration of 1000 mg L-1, as suggested from great stimulation in the activities of antioxidant enzymes and MDA content in roots or leaves. Superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) activities were highly correlated with MDA levels (r2 = 0.963, 0.984, and 0.960, respectively). GO exposure caused significant concentration-dependent membrane depolarization in roots, and significantly inhibited H+ efflux and extracellular Ca2+ influx in root cap.


Assuntos
Grafite/toxicidade , Triticum/efeitos dos fármacos , Antioxidantes/farmacologia , Catalase/metabolismo , Hormese/efeitos dos fármacos , Malondialdeído , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Superóxido Dismutase/metabolismo
8.
Ecotoxicol Environ Saf ; 197: 110608, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32305822

RESUMO

Graphene oxide (GO) has broad application potential in many fields, such as biomedicine and energy. Due to the wide-ranging GO applications, its entry into the environment is inevitable along with the potential for ecological and environmental risks. In the present study, we systematically investigated the dose-dependent effects of three different-sized GO particles (50-200 nm, <500 nm, and >500 nm) on zebrafish during the very early developmental stages (4-124 h post-fertilization). The results showed that GOs could accumulate in the eyes, heart, yolk sac, and blood vessels of fish larvae. Consequently, their effects on multiple toxic endpoints were observed, including delayed hatching times, shortened body lengths, alterations in heart rate and blood flow, changes in swimming activity and responses to photoperiod stimulation, and the enhanced activity of total superoxide dismutase, inducible nitric oxide synthase, acetylcholinesterase, caspase-3, and induction of apoptosis-related gene expression. As a result, the occurrence of oxidative stress and the induction of apoptosis are suggested in fish larvae exposed to all three different-sized GO particles. In addition, our results highlight the impacts of waterborne-GO exposure on zebrafish during early development, which were not merely dependent on GO concentration but also on the associated GO sizes. This study hereby provides a basis for the potential ecological and health risks of GO exposure.


Assuntos
Poluentes Ambientais/toxicidade , Grafite/toxicidade , Acetilcolinesterase/metabolismo , Animais , Apoptose/genética , Caspase 3/metabolismo , Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Poluentes Ambientais/farmacocinética , Expressão Gênica/efeitos dos fármacos , Grafite/farmacocinética , Larva/efeitos dos fármacos , Larva/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula , Superóxido Dismutase/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/metabolismo
9.
Nanotoxicology ; 14(5): 667-682, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32141807

RESUMO

Graphene oxide (GO) is an increasingly important nanomaterial that exhibits great promise in the area of bionanotechnology and nanobiomedicine. However, the toxic effects of GO on the vertebrate developmental system are still poorly understood. Here, we aimed to investigate the toxic effects and molecular mechanisms of GO exposure in larval and adult zebrafish. The results showed that the major hepatotoxic phenotype induced by GO in zebrafish embryos was a significant decrease in liver area and a dose-dependent decrease in the hepatocytes. Moreover, the number of macrophages and neutrophils in zebrafish embryos were reduced but the expressions of pro-inflammatory cytokines were increased after GO treatment. High through-put RNA-Seq identified 314 differentially expressed genes (DEGs) in GO-induced zebrafish embryos including 192 up-regulated and 122 down-regulated. KEGG and GO functional analysis revealed that steroid hormone biosynthesis, lipoprotein metabolic process, and PPAR signaling pathway were significantly enriched. Most of the lipid metabolism genes were down-regulated while majority of the immune genes were up-regulated after GO treatment. Moreover, GO induced NF-κB p65 into the nucleus and increased the protein levels of NF-κB p65, JAK2, STAT3, and Bcl2 in adult zebrafish liver. In addition, pharmacological experiments showed that inhibition of ROS and blocking the MAPK signaling could rescue the hepatotoxic phenotypes induced by GO exposure. On the contrary, pharmacological activation of PPAR-α expression have increased the hepatotoxic effects in GO-induced larval and adult zebrafish. Taken together, these informations demonstrated that GO induced hepatic dysfunction mainly through the ROS and PPAR-α mediated innate immune signaling in zebrafish.


Assuntos
Grafite/toxicidade , Imunidade Inata/efeitos dos fármacos , Fígado/efeitos dos fármacos , Nanopartículas/toxicidade , Peixe-Zebra/imunologia , Animais , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/imunologia , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Grafite/química , Larva/efeitos dos fármacos , Larva/imunologia , Larva/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Fígado/imunologia , Macrófagos/citologia , Nanopartículas/química , Neutrófilos/citologia , Transdução de Sinais , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
10.
Mar Pollut Bull ; 151: 110838, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32056628

RESUMO

Graphene nanoparticles are increasingly released into the aquatic environment with the growth of production. However, there are rare investigations focusing on the interaction of nanoparticles with other contaminants. Triphenyl phosphate (TPP) is a frequently detected organophosphate flame retardant in the environment. This study aimed to assess the joint effects of graphene and TPP on Mytilus galloprovincialis hemocytes. Oxidative stress could be induced by graphene and TPP in mussel hemocytes, which could further cause apoptosis, DNA damage and decrease in the lysosomal membrane stability (LMS). Moreover, hemocytes could internalize graphene, thereby resulting in oxidative stress. The oxidative stress and DNA damage in hemocytes were increased in the graphene-exposed group, but significantly reduced after combined exposure of graphene and TPP. The up-regulated genes, including NF-κB, Bcl-2 and Ras, were mainly associated with reduced apoptosis and DNA damage after co-exposure to graphene and TPP.


Assuntos
Grafite/toxicidade , Mytilus/fisiologia , Organofosfatos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Hemócitos/metabolismo
11.
Ecotoxicol Environ Saf ; 192: 110304, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32066006

RESUMO

The environmental release of graphene oxide (GO) will certainly induce the GO exposure to plants. To date, the influence of GO on the intracellular structures and the endophytic bacterial ecology of plants have been rarely reported. In the present study, the rice seedlings were exposed to GO (5 mg/L) under hydroponic condition for fifteen days with periodic stir. The cellular structures damage, GO deposition and oxidative stress were found in rice root after GO exposure. A Illumina analysis based on the bacterial 16 S rRNA gene showed that the richness, evenness and diversity of endophytic bacterial communities of rice root decreased due to GO exposure. The relative abundance of beneficial endophytic bacterial populations decreased after GO exposure. Out of potential phenotypes predicted by BugBase, the relative abundance of Gram negative, stress-tolerant and biofilm-forming phenotypes, presented an increase trend after GO exposure.


Assuntos
Grafite/toxicidade , Microbiota/efeitos dos fármacos , Oryza/microbiologia , Poluentes Químicos da Água/toxicidade , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Endófitos/classificação , Endófitos/efeitos dos fármacos , Endófitos/genética , Endófitos/isolamento & purificação , Grafite/metabolismo , Hidroponia , Oryza/efeitos dos fármacos , Oryza/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Plântula/efeitos dos fármacos , Plântula/metabolismo , Plântula/microbiologia , Poluentes Químicos da Água/metabolismo
12.
Artigo em Inglês | MEDLINE | ID: mdl-32053040

RESUMO

The increased applications of nanomaterials in industry and biomedicine have resulted in a rising concern about their possible toxic impacts on living organisms. It has been claimed that the phytosynthesized nanomaterials have lower toxicity in comparison to their chemically synthesized counterparts. Therefore, it is important to evaluate their toxic effects on the environment. In the present study, we investigated the toxic effects of microwave-synthesized silver-reduced graphene oxide nanocomposites (MS-Ag-rGO) on Chlorella vulgaris. Algal cells were treated by 1, 2, 4 and 6 mg L-1 MS-Ag-rGO for 24 h. The obtained data with three replicates were examined using analysis of variance. Analysis of different growth parameters revealed that MS-Ag-rGO possessed significant dose-dependent toxic effect on C. vulgaris. Scanning electron microscope and fluorescence microscope images of the treated cells established morphological shrinkages and alteration in position of nucleoli. Moreover, reduction in the phenol and flavonoid contents, enhancement of H2O2 content, changes in the antioxidant enzymes activity and decreases in the growth parameters as well as photosynthetic pigments quantities confirmed the toxicity of MS-Ag-rGO to the C. vulgaris cells. Our findings revealed that MS-Ag-rGO possessed higher toxicity on C. vulgaris than Ag-rGO synthesized by hydrothermal technique.


Assuntos
Chlorella vulgaris/efeitos dos fármacos , Grafite/toxicidade , Microalgas/efeitos dos fármacos , Micro-Ondas , Nanocompostos/toxicidade , Prata/toxicidade , Chlorella vulgaris/ultraestrutura , Relação Dose-Resposta a Droga , Grafite/química , Química Verde , Peróxido de Hidrogênio/metabolismo , Microalgas/ultraestrutura , Nanocompostos/química , Óxidos , Prata/química , Compostos de Prata
13.
Environ Pollut ; 260: 113847, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32000020

RESUMO

Though the main toxic mechanisms of graphene oxide (GO) to algae have been accepted as the shading effect, oxidative stress and mechanical damage, the effect of algal characteristics on these three mechanisms of GO toxicity have seldom been taken into consideration. In this study, we investigated GO toxicity to green algae (Chlorella vulgaris, Scenedesmus obliquus, Chlamydomonas reinhardtii), cyanobacteria (Microcystis aeruginosa) and diatoms (Cyclotella sp.). The aim was to assess how the physiological characteristics of algae affect the toxicity of GO. Results showed that 10 mg/L of GO significantly inhibited the growth of all tested algal types, while S. obliquus and C. reinhardtii were found to be the most susceptible and tolerant species, respectively. Then, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the physiological characteristics of the assessed algae. The presence of locomotive organelles, along with smaller and more spherical cells, was more likely to alleviate the shading effect. Variations in cell wall composition led to different extents of mechanical damage as shown by Cyclotella sp. silica frustules and S. obliquus autosporine division being prone to damage. Meanwhile, growth inhibition and cell division were significantly correlated with the oxidative stress and membrane permeability, suggesting the latter two indicators can effectively signal GO toxicity to algae. The findings of this study provide novel insights into the toxicity of graphene materials in aquatic environments.


Assuntos
Clorófitas , Cianobactérias , Diatomáceas , Grafite , Clorófitas/efeitos dos fármacos , Clorófitas/fisiologia , Cianobactérias/efeitos dos fármacos , Cianobactérias/fisiologia , Diatomáceas/efeitos dos fármacos , Diatomáceas/fisiologia , Grafite/toxicidade
14.
Environ Sci Pollut Res Int ; 27(1): 264-278, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31786761

RESUMO

The rapidly growing interest in using graphene-based nanoparticles in a wide range of applications increases human exposure and risk. However, very few studies have investigated the genotoxicity and mutagenicity of the widely used graphene oxide (GO) nanoparticles in vivo. Consequently, this study estimated the possible genotoxicity and mutagenicity of GO nanoparticles as well as possible oxidative stress induction in the mice liver and brain tissues. Nano-GO particles administration at the dose levels of 10, 20, or 40 mg/kg for one or five consecutive days significantly increased the DNA breakages in a dose-dependent manner that disrupts the genetic material and causes genomic instability. GO nanoparticles also induced mutations in the p53 (exons 6&7) and presenilin (exon 5) genes as well as increasing the expression of p53 protein. Positive p53 reaction in the liver (hepatic parenchyma) and brain (cerebrum, cerebellum, and hippocampus) sections showed significant increase of p53 immunostaining. Additionally, induction of oxidative stress was proven by the significant dose-dependent increases in the malondialdehyde level and reductions in both the level of reduced glutathione and activity of glutathione peroxidase observed in GO nanoparticles administered groups. Acute and subacute oral administration of GO nanoparticles induced genomic instability and mutagenicity by induction of oxidative stress in the mice liver and brain tissues.


Assuntos
Grafite/toxicidade , Nanopartículas/toxicidade , Animais , Encéfalo/efeitos dos fármacos , Dano ao DNA , Instabilidade Genômica , Grafite/química , Humanos , Fígado/efeitos dos fármacos , Masculino , Camundongos , Mutagênese , Mutagênicos/toxicidade , Estresse Oxidativo , Proteína Supressora de Tumor p53
15.
Chemosphere ; 243: 125316, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31733537

RESUMO

Graphene oxide (GO) is part of a new set of nanomaterials with particular characteristics related to its nanoscale size. Due to this feature, it presents high reactivity and other contaminants present in the environment could bind to them and affect its intrinsic toxicity. The metabolic effects of such nanomaterials and their combination with two common pollutants, zinc and cadmium, on the freshwater fish Geophagus iporangensis are analyzed. Moreover, metabolic rate and ammonia excretion were used as bioindicators to measure metabolic changes. Fishes were exposed for 24 h in filtered tap water to different concentrations of GO (0.5; 1.0; 2.0 and 4.0 mg L-1), Zn (0.5; 1.0; 2.0; 4.0 and 10.0 mg L-1) and Cd (0.1; 0.5; 1.0; 2.0 and 4.0 mg L-1). Combined effects were verified using the same concentrations of trace elements added to 1.0 mg L-1 of GO. Exposure to GO and Cd resulted in a decrease of metabolic rate in G. iporangensis, by about 30% compared to control means, in the highest concentration tested (4.0 mg L-1). However, zinc exposure in the highest concentration (10 mg L-1) raised metabolic rate to around three times that of the control group. Ammonia excretion was not affected by exposure to GO and Cd. In contrast, exposure to Zn at 10 mg L-1 raised the rate to around 47%. The combined exposure of GO and Zn intensified the effects of the trace element, inducing responses in both biomarkers at lower concentrations and demonstrating that the interaction between elements increases zinc's effects. The combination Cd + GO only affects metabolic rate. Thus, this metabolic rate alone reveals that combined exposure potentiates effects of trace elements on fish metabolism.


Assuntos
Peixes/fisiologia , Grafite/toxicidade , Oligoelementos/toxicidade , Poluentes Químicos da Água/toxicidade , Amônia/metabolismo , Animais , Cádmio/toxicidade , Biomarcadores Ambientais , Peixes/metabolismo , Água Doce , Alimentos Marinhos , Oligoelementos/análise , Poluentes Químicos da Água/análise , Zinco/toxicidade
16.
Ecotoxicol Environ Saf ; 189: 110051, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31812022

RESUMO

Naphthalene has remained a challenge how to eradicate it from the water because of its carcinogenic risk to humans. In the present study, naphthalene prominently increased the rates of embryonic mortality and malformation, and decreased the hatchability of zebrafish which have a high developmental similarity to humans. Moreover, multiple-organ toxicity were notably found in naphthalene-treated zebrafish. Here, irradiated graphene aerogel (IGA) was successfully prepared from high-energy electron beam to generate more wrinkles, folds, defects and a strong absorption capability for naphthalene, compared with the non-irradiated graphene aerogel. IGA was outstandingly found to remove naphthalene from the embryo culture medium, and subsequently inhibit the embryotoxicity and maintain tissue integrity by restoring cardiac function, attenuating apoptosis signals, recovering eye morphology and structure, reducing expression of heat shock protein 70 in the tissues and promoting behavioral capacity. Meanwhile, no obvious negative impact of IGA was found in the developing zebrafish from embryo to larvae. Consequently, reduction in the toxicity of naphthalene during zebrafish embryogenesis was mediated by IGA as an advanced strategy.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Grafite/química , Naftalenos/análise , Poluentes Químicos da Água/análise , Peixe-Zebra , Animais , Grafite/efeitos da radiação , Grafite/toxicidade , Hidrogéis , Larva/efeitos dos fármacos , Naftalenos/toxicidade , Propriedades de Superfície , Testes de Toxicidade Aguda , Poluentes Químicos da Água/toxicidade
17.
Environ Toxicol ; 35(1): 87-96, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31515868

RESUMO

Increasing consumption of metal-oxide nanoparticles (NPs) and carbon-based nanomaterials has caused significant concern about their potential hazards in aquatic environments. The release of NPs into aquatic environments could result in adsorption of NPs on microorganisms. While metal-oxide NP-conjugated carbon-based nanohybrids (NHs) may exhibit enhanced toxicity toward microorganisms due to their large surface area and the generation of reactive oxygen species (ROS), there is a lack of information regarding the ecotoxicological effects of NHs on marine diatom algae, which are an indicator of marine pollution. Moreover, there is scant information on toxicity mechanisms of NHs on aquatic organisms. In this study, four NHs (ie, ZnO-conjugated graphene oxide [GO], ZnO-conjugated carbon nanotubes [CNTs], TiO2 -conjugated GO, and TiO2 -conjugated CNT) that were synthesized by a hydrothermal method were investigated for their toxicity effects on a Thalassiosira pseudonana marine diatom. The in vitro cellular viability and ROS formation employed at the concentration ranges of 50 and 100 mg/L of NHs over 72 hours revealed that ZnO-GO had the most negative effect on T. pseudonana. The primary mechanism identified was the generation of ROS and GO-induced dispersion that caused electrostatic repulsion, preventing aggregation, and an increase in surface areas of NHs. In contrast to GO-induced dispersion, large aggregates were observed in ZnO/TiO2 -conjugated CNT-based NHs. The scanning electron microscopy images suggest that NHs covered algae cells and interacted with them (shading effects); this reduced light availability for photosynthesis. Detailed in vitro toxicity effects and mechanisms that cause high adverse acute toxicity on T. pseudonana were unveiled; this implied concerns about potential hazards of these mechanisms in aquatic ecosystems.


Assuntos
Diatomáceas/efeitos dos fármacos , Grafite/toxicidade , Nanotubos de Carbono/toxicidade , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Óxido de Zinco/toxicidade , Organismos Aquáticos/efeitos dos fármacos , Organismos Aquáticos/crescimento & desenvolvimento , Sobrevivência Celular/efeitos dos fármacos , Diatomáceas/crescimento & desenvolvimento , Ecossistema , Grafite/química , Nanotubos de Carbono/química , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Propriedades de Superfície , Titânio/química , Poluentes Químicos da Água/química , Óxido de Zinco/química
18.
J Environ Sci (China) ; 88: 200-208, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31862061

RESUMO

Exposure to engineered nanomaterials (ENMs), such as graphene oxide (GO), can potentially induce the response of various molecular signaling pathways, which can mediate the protective function or the toxicity induction. Wnt signaling pathway is conserved evolutionarily in organisms. Using Caenorhabditis elegans as an in vivo assay model, we investigated the effect of GO exposure on intestinal Wnt signaling. In the intestine, GO exposure dysregulated Frizzled receptor MOM-5, Disheveled protein DSH-2, GSK-3 (a component of APC complex), and two ß-catenin proteins (BAR-1 and HMP-2), which mediated the induction of GO toxicity. In GO exposed nematodes, a Hox protein EGL-5 acted as a downstream target of BAR-1, and fatty acid transport ACS-22 acted as a downstream target of HMP-2. Functional analysis on HMP-2 and ACS-22 suggested that the dysregulation of these two proteins provides an important basis for the observed deficit in functional state of intestinal barrier. Our results imply the association of dysregulation in physiological and functional states of intestinal barrier with toxicity induction of GO in organisms.


Assuntos
Caenorhabditis elegans/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Grafite/toxicidade , Via de Sinalização Wnt/efeitos dos fármacos , Animais , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Ciclo Celular , Proteínas Desgrenhadas , Quinase 3 da Glicogênio Sintase , Intestinos , Óxidos
19.
Sci Total Environ ; 700: 134492, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31627046

RESUMO

Graphene oxide (GO) is a carbon-based engineered nanomaterial (ENM). Using Caenorhabditis elegans as an animal model, we investigated the effect of GO exposure on protein-protein interactions. In nematodes, NLG-1/Neuroligin, a postsynaptic protein, acted only in the neurons to regulate the GO toxicity. In the neurons, DLG-1, a PSD-95 protein, and MAGI-1, a S-SCAM protein, were identified as the downstream targets of NLG-1 in the regulation of GO toxicity. PKC-1, a serine/threonine protein kinase C, further acted downstream of neuronal DLG-1 and MAGI-1 to regulate the GO toxicity. Co-immunoprecipitation analysis demonstrated the protein-protein interaction between NLG-1 and DLG-1 or MAGI-1. After GO expression, this protein-protein interaction between NLG-1 and DLG-1 or MAGI-1 was significantly inhibited. Therefore, our data raised the evidence to suggest the potential of GO exposure in disrupting protein-protein interactions in organisms.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiologia , Grafite/toxicidade , Substâncias Perigosas/toxicidade , Animais , Moléculas de Adesão Celular Neuronais/metabolismo , Guanilato Quinases
20.
Anal Chim Acta ; 1095: 204-211, 2020 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-31864624

RESUMO

The abnormal expression of sialic acids (SAs) on cells and tissues is closely related to various pathophysiological states. Here we applied phenylboronic acid (PBA) functionalized graphitic carbon nitride fluorescent quantum dots (PCQDs) with sizes from 3 to 5 nm in efficient and selective labeling SAs on the surface of living cells and tissues. With abundant PBA in their structure, the water soluble PCQDs showed the relative SA level on the cell surface via selectively and efficiently staining different cell lines in 30 min and revealed that M1 macrophages may express more SAs on their surfaces compared with M0 and M2. The distinct demarcation of cancerous and para-noncancerous areas on cancer tissue sections was showed by PCQDs staining. PCQDs with their high selectivity, stable photoluminescence, low cost, and nontoxicity can be an ideal SA fluorescent probe for living cells and tissues.


Assuntos
Corantes Fluorescentes/química , Grafite/química , Ácido N-Acetilneuramínico/análise , Compostos de Nitrogênio/química , Pontos Quânticos/química , Animais , Ácidos Borônicos/química , Ácidos Borônicos/toxicidade , Linhagem Celular Tumoral , Corantes , Corantes Fluorescentes/toxicidade , Grafite/toxicidade , Humanos , Pulmão/metabolismo , Pulmão/patologia , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Camundongos , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Ácido N-Acetilneuramínico/metabolismo , Compostos de Nitrogênio/toxicidade , Pontos Quânticos/toxicidade , Células RAW 264.7 , Coloração e Rotulagem
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