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1.
Aquat Toxicol ; 214: 105263, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31376794

RESUMO

The potential toxicity of silver nanoparticles (AgNPs) to the early stages of fish is still unclear. This study used zebrafish embryos as a model to investigate the toxic effects of AgNPs on ion regulation by skin ionocytes. Zebrafish embryos were exposed to AgNPs for 96 h (4-100 h post-fertilization (hpf)) or 4 h (96-100 hpf). After 96 h of exposure to 5 and 10 mg/L AgNPs, survival rates had decreased to 42% and 0%, respectively; the body length had also significantly decreased at 5 mg/L. Whole-body Na+ and K+ contents significantly decreased at 1 and 3 mg/L, while Ca2+ contents decreased at ≥0.1 mg/L. H+ secretion by the skin significantly decreased at 1 mg/L. The density of skin ionocytes labeled with rhodamine 123 (a mitochondrion marker) decreased by 25% and 55% at 1 and 3 mg/L, respectively; and 54% of ionocytes (at 3 mg/L) were deformed from an oval to a spinous shape. After 4 h of exposure to 1 and 5 mg/L, whole-body Na+ and Ca2+ contents, H+ secretion, and density of ionocytes had also significantly decreased. This study revealed the toxicity of AgNPs to skin ionocytes and ion regulation in the early stages of zebrafish embryos.


Assuntos
Embrião não Mamífero/metabolismo , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Peixe-Zebra/embriologia , Ácidos/metabolismo , Animais , Contagem de Células , Forma Celular/efeitos dos fármacos , Embrião não Mamífero/citologia , Embrião não Mamífero/efeitos dos fármacos , Íons , Larva/efeitos dos fármacos , Análise de Sobrevida , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/anatomia & histologia
2.
Int J Nanomedicine ; 14: 4723-4739, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31308655

RESUMO

Background: Much consideration has been paid to the toxicological assessment of nanoparticles prior to clinical and biological applications. While in vitro studies have been expanding continually, in vivo investigations of nanoparticles have not developed a cohesive structure. This study aimed to assess the acute toxicity of different concentrations of chitosan-coated silver nanoparticles (Ch-AgNPs) in main organs, including liver, kidneys, and spleen. Materials and methods: Twenty-eight male albino rats were used and divided into 4 groups (n=7). Group 1 was kept as a negative control group. Groups 2, 3, and 4 were treated intraperitoneally with Ch-AgNPs each day for 14 days at doses of 50, 25, and 10 mg/kg body weight (bwt) respectively. Histopathological, morphometric and immunohistochemical studies were performed as well as oxidative stress evaluations, and specific functional examinations for each organ were elucidated. Results: It was revealed that Ch-AgNPs induced dose-dependent toxicity, and the repeated dosing of rats with 50 mg/kg Ch-AgNPs induced severe toxicities. Histopathological examination showed congestion, hemorrhage, cellular degeneration, apoptosis and necrosis in hepatic and renal tissue as well as lymphocytic depletion with increasing tangible macrophages in the spleen. The highest levels of malondialdehyde, alanine aminotransferase, aspartate aminotransferase (MDA, ALT, AST) and the lowest levels of reduced glutathione, immunoglobulin G, M and total protein (GSH, IgG, IgM, TP) were observed in this group. On the other hand, repeated dosing with 25 mg/kg induced mild to moderate disturbance in the previous parameters, while there was no significant difference in results of pathological examination and biochemical tests between the control group and those treated with 10 mg/kg bwt Ch-AgNPs. Conclusion: Chitosan-coated silver nanoparticles induce dose-dependent adverse effects on rats.


Assuntos
Quitosana/química , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Nitrogênio da Ureia Sanguínea , Caspase 3/metabolismo , Creatinina/sangue , Glutationa/metabolismo , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Malondialdeído/metabolismo , Nanopartículas Metálicas/ultraestrutura , Estresse Oxidativo/efeitos dos fármacos , Antígeno Nuclear de Célula em Proliferação/metabolismo , Ratos Wistar , Baço/efeitos dos fármacos , Baço/patologia
3.
Environ Monit Assess ; 191(8): 497, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31312907

RESUMO

A few studies had determined the effects of silver nanoparticles on the development of Drosophila melanogaster. However, none had addressed its genotoxic effects on specific larval cells of the fly in details. This study was conducted to determine the effects of silver nanoparticle on the development of D. melanogaster with simultaneous evaluation of its genotoxic potential on specific larval cell types that play important roles in immunological defenses as well as growth and development. Five male and five female flies were maintained in standard Drosophila melanogaster culture medium containing varying concentrations of silver nanoparticles, i.e., 25, 50, 100, 200, and 300 mg/l with control culture medium containing no nanoparticle. Total time needed for stage-specific development, population yield, and genotoxic effects on third instar larval polytene chromosomes, hemocytes, and neuroblasts was determined. Body pigmentation of pupae and young adults was examined visually. In comparison with control, silver nanoparticles dose dependently inhibited the metamororphosis and population yields of pupae and young adults of Drosophila melanogaster. Every concentration of the nanoparticles inhibited pupa to adult conversion, with huge reduction under the influence of nanoparticle concentration of 100 mg/ml and above. Developmental inhibition was accompanied by dose-dependent and significant structural aberrations of larval polytene chromosomes and deformities of hemocytes and neuroblasts. Pupae and young adults also exhibited gradual discoloration of body with the increase in exposure to nanoparticle concentration.


Assuntos
Dano ao DNA , Drosophila melanogaster/efeitos dos fármacos , Larva/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Células-Tronco Neurais/efeitos dos fármacos , Prata/toxicidade , Animais , Relação Dose-Resposta a Droga , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Monitoramento Ambiental , Feminino , Larva/genética , Larva/crescimento & desenvolvimento , Masculino , Pupa/efeitos dos fármacos , Pupa/genética , Pupa/crescimento & desenvolvimento
4.
Environ Pollut ; 253: 578-598, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31330350

RESUMO

Silver nanoparticles (AgNPs) are widely incorporated in many products, partly due to their antimicrobial properties. The subsequent discharge of this form of silver into wastewater leads to an accumulation of silver species (AgNPs and derivatives resulting from their chemical transformation), in sewage sludge. As a result of the land application of sewage sludge for agricultural or remediation purposes, soils are the primary receiver media of silver contamination. Research on the long-term impact of AgNPs on the environment is ongoing, and this paper is the first review that summarizes the existing state of scientific knowledge on the potential impact of silver species introduced into the soil via sewage sludge, from microorganisms to earthworms and plants. Silver species can easily enter cells through biological membranes and affect the physiology of organisms, resulting in toxic effects. In soils, exposure to AgNPs may change microbial biomass and diversity, decrease plant growth and inhibit soil invertebrate reproduction. Physiological, biochemical and molecular effects have been documented in various soil organisms and microorganisms. Negative effects on organisms of the dominant form of silver in sewage sludge, silver sulfide (Ag2S), have been observed, although these effects are attenuated compared to the effects of metallic AgNPs. However, silver toxicity is complex to evaluate and much remains unknown about the ecotoxicology of silver species in soils, especially with respect to the possibility of transfer along the trophic chain via accumulation in plant and animal tissues. Critical points related to the hazards associated with the presence of silver species in the environment are described, and important issues concerning the ecotoxicity of sewage sludge applied to soil are discussed to highlight gaps in existing scientific knowledge and essential research directions for improving risk assessment.


Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Poluentes do Solo/toxicidade , Poluentes Químicos da Água/toxicidade , Agricultura , Animais , Biomassa , Ecotoxicologia , Nanopartículas Metálicas/química , Oligoquetos/efeitos dos fármacos , Plantas/efeitos dos fármacos , Esgotos/química , Compostos de Prata/toxicidade , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise , Águas Residuárias/química
5.
Environ Pollut ; 252(Pt B): 1539-1549, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31277023

RESUMO

Silver nanoparticles (AgNPs) have adverse impacts on plants when released into environments, but their toxic mechanism is still a matter of debate. Here we present a combined analysis of physiology and transcriptome of Arabidopsis thaliana leaves exposure to 30 mg L-1 AgNPs and Ag+ for six days to explore the toxicity mechanism of AgNPs on Arabidopsis. Both transcriptomic and physiological results showed that AgNPs induced reactive oxygen species (ROS) accumulation and damaged photosynthesis. The toxicity of AgNPs is not merely attributable to Ag+ release and much higher photosynthetic toxicity and ROS accumulation were observed in 30 mg L-1 AgNPs than that in 0.12 mg L-1 Ag+. About 60% genes were similarly up- or down-regulated at the same concentration of AgNPs and Ag+ and these genes were enriched in photosynthesis and response to the stimulus. However, 302 genes, including those involved in glucosinolates synthesis, were specifically regulated under AgNPs treatments. In conclusion, more than the released Ag+, nanoparticle-specific effects are responsible for the toxicity of AgNPs in Arabidopsis thaliana.


Assuntos
Arabidopsis/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Fotossíntese/efeitos dos fármacos , Prata/toxicidade , Transcriptoma/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/metabolismo , Fotossíntese/genética , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismo
6.
Aquat Toxicol ; 213: 105221, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207537

RESUMO

Engineered nanomaterials (ENMs) tend to precipitate in saline waters so the majority of aquatic toxicity studies have focused on freshwaters, where bioavailability is presumed to be higher. Recent studies have illustrated that some ENM formulations are bioavailable and bioactive in salt water and that their effects are more pronounced at the physiological than biochemical level. These findings raise concerns regarding the effects of ENMs on marine organisms. Therefore, our goal was to characterize the effects of polyvinylpyrolidone-functionalized silver ENMs (nAg) on aerobic performance in the killifish (Fundulus heteroclitus), a common euryhaline teleost. Fish were exposed to 80 µg L-1 of 5 nm nAg for 48 h in brackish water (12 ppt) and routine (MO2min) and maximum (MO2max) rates of oxygen consumption were quantified. Silver dissolution was minimal and nAg remained well dispersed in brackish water, with a hydrodynamic diameter of 21.0 nm, compared to 19.3 in freshwater. Both MO2min and MO2max were significantly lower (by 53 and 30%, respectively) in killifish exposed to nAg and a reduction in MO2 variability suggested spontaneous activity was suppressed. Neither gill Na+/K+-ATPase activity, nor various other biochemical markers were affected by nAg exposure. The results illustrate that a common ENM formulation is bioactive in salt water and, as in previous studies on functionalized copper ENMs, that effects are more pronounced at the whole animal than the biochemical level.


Assuntos
Água Doce , Fundulidae/fisiologia , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Testes de Toxicidade , Acetilcolinesterase/metabolismo , Aerobiose , Animais , Metabolismo Basal/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Fundulidae/sangue , Brânquias/efeitos dos fármacos , Brânquias/ultraestrutura , Hidrocortisona/sangue , Fígado/metabolismo , Nanopartículas Metálicas/ultraestrutura , Consumo de Oxigênio/efeitos dos fármacos , ATPase Trocadora de Sódio-Potássio/metabolismo , Poluentes Químicos da Água/toxicidade
7.
Environ Sci Pollut Res Int ; 26(22): 22529-22550, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161543

RESUMO

Widespread application of silver nanoparticles (AgNPs), due to their antibacterial and antifungal properties, increases their release into the environment and potential detrimental impact on living organisms. Plants may serve as a potential pathway for AgNPs bioaccumulation and a route into the food chain, hence investigation of AgNP phytotoxic effects are of particular importance. Since proteins are directly involved in stress response, studies of their abundance changes can help elucidate the mechanism of the AgNP-mediated phytotoxicity. In this study, we investigated proteomic changes in tobacco (Nicotiana tabacum) exposed to AgNPs and ionic silver (AgNO3). A high overlap of differently abundant proteins was found in root after exposure to both treatments, while in leaf, almost a half of the proteins exhibited different abundance level between treatments, indicating tissue-specific responses. Majority of the identified proteins were down-regulated in both tissues after exposure to either AgNPs or AgNO3; in roots, the most affected proteins were those involved in response to abiotic and biotic stimuli and oxidative stress, while in leaf, both treatments had the most prominent effect on photosynthesis-related proteins. However, since AgNPs induced higher suppression of protein abundance than AgNO3, we conclude that AgNP effects can, at least partially, be attributed to nanoparticle form.


Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Tabaco/fisiologia , Íons , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteoma/metabolismo , Proteômica , Nitrato de Prata/toxicidade , Tabaco/metabolismo
8.
Carbohydr Polym ; 220: 22-29, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31196544

RESUMO

The control of chitosan/silver nanoparticle composite microsphere (CAgMs) size is crucial for tuning its function. In the current work, monodisperse organically-modified CAgMs with controllable size were synthesized using a two-step method. The fine-tuning of the microsphere size was confirmed by many reaction parameters while the cross-linking agent was the key research object. Through physical and thermodynamic analysis, we found the cross-linking agent-induced smaller size, higher silver concentration, more heightened glass transition temperature and stronger hydrogen bond network. The as-prepared microspheres exhibited strong bacteriostasis and fresh-keeping function depending on cross-linking agent concentration. The phenomenon is believed to be derived from the difference in microorganism adsorption and killing ability from induced varying specific surface area and encapsulated silver content. Our current work highlights the size-controllable preparation of CAgMs, and based on our findings, small size CAgMs can be a promising candidate in the field of antibacterial and fruit preservation applications.


Assuntos
Antibacterianos/farmacologia , Quitosana/toxicidade , Conservação de Alimentos/métodos , Malpighiaceae/microbiologia , Nanopartículas Metálicas/toxicidade , Microesferas , Prata/toxicidade , Quitosana/química , Escherichia coli/efeitos dos fármacos , Nanopartículas Metálicas/química , Tamanho da Partícula , Penicillium/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos
9.
Environ Pollut ; 252(Pt A): 931-940, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31229850

RESUMO

The widely usage of silver nanoparticles in a range of consumer products inevitably results in its being released to the wastewater. As a result, the potential negative effects associated with AgNPs on wastewater treatment systems need to be assessed to develop the regulatory guidelines. In this paper, the exposure experiment at environmentally relevant concentration (100 µg L-1) were conducted to demonstrate the effects of AgNPs on the pollutant removals in constructed wetlands (CWs) with different plants and the spatial distribution of silver. Before adding AgNPs, the system with Arundo donax (VF2) had the better nitrogen removal than Cyperus alternifolius (VF1). After exposure for about 94 d, the average removal efficiencies of NH4+-N significantly reduced by 32.43% and 23.92%, TN of 15.82% and 17.18% and TP of 22.74% and 20.46% in VF1 and VF2, respectively, while the COD removal had no difference. However, presence of 100 µg L-1 AgNPs for about 450 d showed no inhibition effects on nutrient removals in two experimental CWs. Two wetlands showed high removal efficiencies of about 98% on AgNPs, indicating CWs could play a crucial role to control the AgNPs release to environment. It was found that AgNPs mainly accumulated in the soil layer with the Ag content of 0.45-5.96 µg g-1 dry weight in lower soil and 2.84-11.37 µg g-1 dry weight in upper soil. The roots of Cyperus alternifolius absorbed more AgNPs, with higher bioconcentration factors (1.32-1.44) than that of 0.59 in Arundo donax. The differences of translocation factors on leaves and stems in two test plants showed that AgNPs assimilated by roots in Cyperus alternifolius were more easily transferred to the leaves. The obtained results showed that the macrophyte Cyperus alternifolius could be better choice for immobilization of AgNPs.


Assuntos
Biodegradação Ambiental , Cyperus/metabolismo , Nanopartículas Metálicas/toxicidade , Poaceae/metabolismo , Prata/toxicidade , Poluentes Químicos da Água/análise , Nitrogênio/análise , Solo/química , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Áreas Alagadas
10.
Environ Pollut ; 252(Pt B): 1051-1058, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31252102

RESUMO

Behavioural responses to contaminants are an important endpoint in ecotoxicology because they link effects at biochemical or cellular levels to impacts on individual fitness. Due to the increasing use of silver in nanomaterials, studies of its effects on the behaviour of aquatic organisms are important to assess the risks of silver nanoparticles (AgNP) released into the environment. The aim of this work was to evaluate the behavioural effects of silver on the marine amphipod Echinogammarus marinus after exposure to AgNO3 via water and AgCl or AgNP via food. Swimming activity of the amphipods was tracked during 6 min alternating dark and light conditions. Animals swam slower and responded less to light at higher concentrations of silver in the water. No differences were found in the behaviour of animals exposed via feeding up to 28 days, hence, longer exposure times may be required for the observation of effects. This is the first work to appraise behaviour effects of silver ions and AgNP on marine amphipods. Although the protocol has been successfully developed for this purpose, specimens appeared to habituate to test conditions during the experiments. Therefore, the need for further understanding of baseline behaviours in these model organisms is discussed.


Assuntos
Anfípodes/efeitos dos fármacos , Organismos Aquáticos/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Ecotoxicologia , Íons , Nanopartículas Metálicas/química , Prata/química , Natação , Poluentes Químicos da Água/química
11.
Bull Environ Contam Toxicol ; 103(1): 181-186, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31049596

RESUMO

Silver nanoparticles (AgNPs) is widely used as an antibacterial agent, but the specific antibacterial mechanism is still conflicting. This study aimed to investigate the size dependent inhibition of AgNPs and the relationship between inhibition and reactive oxygen species (ROS). Azotobactervinelandii and Nitrosomonaseuropaea were exposed to AgNPs with different particles size (10 nm and 50 nm). The ROS production was measured and the results showed that the generation of ROS related to the particle size and concentrations of AgNPs. At 10 mg/L of 10 nm Ag particles, the apoptosis rate of A. vinelandii and N. europaea were 20.23% and 1.87% respectively. Additionally, the necrosis rate of A. vinelandii and N. europaea reached to 15.20% and 42.20% respectively. Furthermore, transmission electron microscopy images also indicated that AgNPs caused severely bacterial cell membrane damage. Together these data suggested that the toxicity of AgNPs depends on its particle size and overproduction of ROS.


Assuntos
Azotobacter vinelandii/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Nitrosomonas europaea/efeitos dos fármacos , Prata/toxicidade , Apoptose/efeitos dos fármacos , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Espécies Reativas de Oxigênio/metabolismo
12.
Aquat Toxicol ; 212: 47-53, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31071656

RESUMO

The increasing production of engineered inorganic nanoparticles (EINPs) elevates their release into aquatic ecosystems raising concerns about associated environmental risks. Numerous investigations indicate sediments as the final sink, facilitating the exposure of benthic species to EINPs. Although reports of sub-lethal EINP effects on benthic species are increasing, the importance of exposure pathways (either waterborne or dietary) is poorly understood. This study investigates the influence of two EINPs, namely titanium dioxide (nTiO2) and silver (nAg), on the benthic model organism Gammarus fossarum specifically addressing the relative relevance of these pathways. For each type of EINP an individual 30-day long bioassay was conducted, applying a two-factorial test design. The factors include the presence or absence of the EINPs (nTiO2: ∼80 nm, 4 mg/L or nAg: ∼30 nm, 0.125 mg/L; n = 30) in the water phase (waterborne), combined with a preceding 6-day long aging of their diet (black alder leaves) also in presence or absence of the EINPs (dietary). Response variables were mortality, food consumption, feces production and energy assimilation. Additionally, the physiological fitness was examined using lipid content and dry weight of the organisms as measures. Results revealed a significantly reduced energy assimilation (up to ∼30%) in G. fossarum induced by waterborne exposure towards nTiO2. In contrast, the dietary exposure towards nAg significantly increased the organisms' energy assimilation (up to ∼50%). Hence, exposure pathway dependent effects of EINPs cannot be generalized and remain particle specific resting upon their intrinsic properties affecting their potential to interact with the surrounding environment. As a result of the different properties of the EINPs used in this study, we clearly demonstrated variations in type and direction of observed effects in G. fossarum. The results of the present study are thus supporting current approaches for nano-specific grouping that might enable an enhanced accuracy in predicting EINP effects facilitating their environmental risk assessment.


Assuntos
Anfípodes/efeitos dos fármacos , Exposição Ambiental , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Titânio/toxicidade , Animais , Biomassa , Metabolismo Energético/efeitos dos fármacos , Fezes , Comportamento Alimentar/efeitos dos fármacos , Lipídeos/análise , Tamanho da Partícula , Folhas de Planta/metabolismo , Poluentes Químicos da Água/toxicidade
13.
Chemosphere ; 230: 567-577, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31125885

RESUMO

Effluent from wastewater treatment plants contains a wide variety of engineered nanoparticles (ENPs) released from different sources. Although single type ENPs have been studied extensively with respect to their environmental impact, ENPs in mixed forms have not been investigated much at environmentally relevant concentrations. This study was designed to test the effect of mixed ENPs at three combinations and concentrations on an aquatic bacterial community. After mixing artificial treated wastewater with river water and exposing the microbial community to ENPs for three days, the ENPs were characterized by SP-ICP-MS. Results from this study showed that: 1) the size distribution of Ti and Zn at the beginning and end of the experiment did not vary much among all tested conditions. For Ag, the most frequent size increased more than 2-fold when the highest Ag ENPs were added; 2) particle concentrations of ENPs generally correlated positively with added concentrations; 3) dissolved Zn and Ag increased significantly as a result of spike; and 4) the bacterial community structure was shifted significantly as a consequence of ENPs' addition. With the dominant population being suppressed, the community exposed to ENPs became more diverse and even. Surprisingly, further increase of the doses of the three ENPs did not bring significant change to the microbial community. These results revealed that ENPs could bring significant impacts to prokaryotes even at low concentrations. But these impacts do not necessarily correlate positively with doses.


Assuntos
Nanopartículas Metálicas/toxicidade , Microbiota/efeitos dos fármacos , Rios/microbiologia , Prata/toxicidade , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Óxido de Zinco/toxicidade , Relação Dose-Resposta a Droga , Modelos Teóricos , Águas Residuárias/química
14.
Carbohydr Polym ; 217: 58-68, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31079685

RESUMO

The fruit of Akebia trifoliata var. australis can be consumed as food. However, the peel of this fruit is typically regarded as waste. The application of such waste can create opportunities to produce new and valuable by-products. Herein, we have shown that citric acid extracted pectin (CEP) from Akebia trifoliata var. australis peel has good water solubility and high galacturonic units, which helps reduce AgNO3 into Ag nanoparticles (CEP-AgNPs) through a one-step, eco-friendly process. The resulting CEP-AgNPs showed sustained release of Ag+ and remarkable antibacterial activity. Subsequently, the CEP-AgNPs were processed into a CEP-Ag sponge with excellent water absorption and prolonged water retention properties. The CEP-Ag sponge could support the cell adhesion and proliferation. Most importantly, the sponge effectively facilitated a moist environment with bacterial disinfection capability which accelerated the healing of infected wounds. Thus, CEP-Ag sponge, a sustainable and high value by-product, was obtained from food waste.


Assuntos
Antibacterianos/uso terapêutico , Bandagens , Nanopartículas Metálicas/uso terapêutico , Pectinas/química , Resíduos Sólidos , Cicatrização/efeitos dos fármacos , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/toxicidade , Permeabilidade da Membrana Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Feminino , Fibroblastos/efeitos dos fármacos , Frutas/química , Química Verde/métodos , Humanos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/toxicidade , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pectinas/isolamento & purificação , Pectinas/toxicidade , Ranunculales/química , Ratos Sprague-Dawley , Prata/química , Prata/uso terapêutico , Prata/toxicidade , Nitrato de Prata/química , Pele/patologia , Solubilidade , Água/química , Molhabilidade
15.
Sci Total Environ ; 679: 365-377, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31085416

RESUMO

Human health and environment have been continuously getting exposure to toxic chemicals including nanomaterial; therefore, nontoxicity has recently attracted huge amount of attention. In this study, RU-AgNPs were synthesized by a green synthesis procedure and evaluated for their toxicity in human umbilical vein endothelial cells (HUVECs) as well as on zebrafish embryos via apoptotic pathway. The synthesized RU-AgNPs were average in size (20-25 nm) with a negative surface charge of -13.43 mV. As a result, RU-AgNPs potentiated the formation of reactive oxygen species (ROS) in HUVECs as confirmed by the results of immunoblotting analysis using apoptotic markers, such as Bax, Bcl2, and cytochrome C. Moreover, the induction of apoptosis in HUVECs was also authenticated in a dose-dependent manner after the treatment with RU-AgNPs by the Incucyte analysis. In vivo trials conducted on zebrafish visualized the mortality, malformation, and imbalanced in the heart rate, and cell death of the whole embryo, including severe morphological changes in the yolk sac and the tail of zebrafish. Furthermore, the results of western blot analysis demonstrated the increasing intensity of apoptotic biomarkers such as Bax, Bcl2, and Cyto C, including enhanced production of ROS, validating the cell death in zebrafish larvae. In addition, chemically functionalized silver nanoparticles found to be more cytotoxic than biogenic functionalized silver nanoparticles. Above-mentioned findings clearly demonstrate that Ru-AgNPs cause the toxicity via ROS-induced apoptotic pathway. Therefore, it is necessary to decide RU-AgNPs toxicity levels before being used in any biomedical application.


Assuntos
Apoptose , Embrião não Mamífero/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Estresse Oxidativo , Prata/toxicidade , Animais , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Rumex/metabolismo , Peixe-Zebra
16.
Chemosphere ; 229: 169-180, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31078031

RESUMO

Although silver nanoparticles (AgNPs) are used in various commercial products, the biological effects of AgNPs on fish embryogenesis and the underlying molecular mechanisms are still poorly understood. In this study, both touch responses and neuron membrane potential were found to be abnormal in AgNPs-stressed embryos. Moreover, neurogenesis genes were unveiled to be down-regulated and were enriched in ligand-gated ion channel activity, dopamine receptor signaling pathway, etc. in AgNPs-stressed embryos by microarray assays. Additionally, the down-regulated expression of otpa/sncgb - gad1b/gad2 dopaminergic neurotransmitter genes, robo2 - vim and glrbb synaptic transmission genes, and motor neuron genes isl1 &isl2a was further identified in both AgNPs- and Ag+-stressed embryos by qPCR, whole-mount in situ hybridization (WISH), and by using specific promoter-derived GFP fluorescence transgenic zebrafish. Moreover, the reduced expression of gad1b, gad2, and isl1 could be recovered by adding Ag+ chelating compound l-cysteine in AgNPs stressed embryos. Our results reveal for the first time that it is through damaging the formation of neural circuits, including dopaminergic neurotransmitter, synaptic transmission, and motor activities, that AgNPs induce abnormal electrical membrane properties, leading to dysfunctional touch responses and locomotor escape responses mostly via their released Ag+ during embryogenesis.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Fenômenos Fisiológicos do Sistema Nervoso/efeitos dos fármacos , Prata/química , Prata/toxicidade , Tato/efeitos dos fármacos , Peixe-Zebra/embriologia , Animais , Embrião não Mamífero/fisiologia , Tato/fisiologia , Peixe-Zebra/metabolismo , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
17.
Chemosphere ; 229: 86-93, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31078035

RESUMO

In the environment co-contamination of several toxicants commonly occurs. However, toxicological studies usually are focused on only one toxicant. The aim of this study was to investigate toxicity of silver nanoparticles (AgNP) and mycotoxin fumonisin B1 (FB1) and their possible interactions as well as to explore tentative mechanism of their toxic effect. Duckweed (Lemna minor L.) was treated with AgNP or FB1 (at concentrations 0.5 and 1.0 mg L-1) or with their combination at same concentrations for 3 days. Both AgNP and FB1, applied individually significantly affected levels of certain nutrients, reduced growth rate and the levels of photosynthetic pigments though AgNP at a much greater extent compared to FB1. Furthermore, AgNP induced ROS generation, lipid peroxidation and increase of antioxidative enzymes activities, while FB1 induced changes only in the activities of antioxidative enzymes. Those results implicate that phytotoxicity of both AgNP and FB1 can be associated with imbalance of mineral and cell redox status. However, toxic actions of AgNp singly applied were more pronounced. Combined treatment with AgNP and FB1 produced higher degree of changes in all parameters than corresponding concentrations of AgNP or FB1 alone implying their additive effects. Additionally, higher level of FB1 found in medium, and higher level of intracellular Ag following combined treatment indicates interaction of two toxicants at the transport level/uptake in the cell which resulted in higher accumulation of Ag in duckweed cells. The latter in turn exerted higher toxicity to duckweed compared to single treatment of AgNP.


Assuntos
Araceae/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Fumonisinas/toxicidade , Nanopartículas Metálicas/toxicidade , Prata/química , Prata/toxicidade , Animais , Antioxidantes/metabolismo , Araceae/metabolismo , Interações de Medicamentos , Poluentes Ambientais/metabolismo , Fumonisinas/metabolismo , Nutrientes/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Prata/metabolismo
18.
Ecotoxicol Environ Saf ; 179: 127-134, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31030055

RESUMO

The increasing production of Ag nanoparticle (AgNP) containing products has inevitably led to a growing concern about their release into the aquatic environment, along with their potential behaviour, toxicity, and bioaccumulation in marine organisms exposed to NPs released from these products. Hence, this study is focused on the effects of AgNPs in Saccostrea glomerata (rock oyster) in artificial seawater (ASW); evaluating the NP's stability, dissolution, and bioaccumulation rate. AgNPs NM300K (20 ±â€¯5 nm) in concentrations of 12.5 µgL-1 and 125 µgL-1 were used to conduct the experiments, and were compared to a blank and a positive control of 12.5 µgL-1 AgNO3. Dissolution in ASW was measured by ICP-OES and stability was assessed by TEM after 1 h and 3, 5, and 7 days of exposure. Bioaccumulation in gills and digestive glands was measured after 7 days of exposure. The higher concentration of AgNPs induced more aggregation, underwent less dissolution, and showed less bioaccumulation, while the lower concentration showed less aggregation, more dissolution and higher bioaccumulation. Five biomarkers (EROD: ethoxyresorufin-o-deethylase, DNA strand breaks, LPO: lipid peroxidation, GST: glutathione S-transferase and GR: glutathione reductase) were analysed at 0, 3, 5 and 7 days. Significant differences compared to the initial day of exposure (day 0) were reported in DNA strand breaks after 5 and 7 days of exposure, GST, from the third day of exposure, in all the Ag samples, and in some samples for LPO and GR biomarkers, while no significant induction of EROD was observed. A combined effect for each type of treatment and time of exposure was also reported for DNA strand breaks and GST biomarkers measured at the digestive glands. In general, the significant inductions measured showed the following trend: 125 µgL-1 AgNPs >12.5 µgL-1 AgNPs ∼12.5 µgL-1 AgNO3 even though bioaccumulation followed the opposite trend.


Assuntos
Nanopartículas Metálicas/toxicidade , Ostreidae/efeitos dos fármacos , Ostreidae/metabolismo , Prata/metabolismo , Prata/toxicidade , Animais , Biomarcadores/metabolismo , Sistema Digestório/efeitos dos fármacos , Sistema Digestório/metabolismo , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Glutationa Redutase/metabolismo , Glutationa Transferase/metabolismo , Íons/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Água do Mar/química
19.
Environ Pollut ; 250: 728-736, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31035155

RESUMO

Rapid development in nanotechnology and incorporation of silver nanoparticles (AgNPs) in wide range of consumer products causing the considerable release of these NPs in the environment, leading concerns for ecosystem safety and plant health. In this study, rice (Oryza sativa) was exposed to AgNPs (0, 100, 200, 500 and 1000 mg L-1) in biochar amended (2 %w/v) and un-amended systems. Exposure of plants to AgNPs alone reduced the root and shoot length, biomass production, chlorophyll contents, photosynthesis related physiological parameters as well as macro-and micronutrients in a dose dependent manner. However, in case of biochar amendment, physiological parameters i.e., net photosynthesis rate, maximum photosynthesis rate, CO2 assimilation, dark respiration and stomatal conductance reduced only 16, 6, 7, 3 and 8%, respectively under AgNPs exposure at 1000 mg L-1 dose. Meanwhile, biochar at all exposure level of AgNPs decreased the bioaccumulation of Ag in rice root and shoot tissues, thus alleviated the phyto-toxic effects of NPs on plant growth. Moreover, results showed that biochar reduced the bioavailability of AgNPs by surface complexation, suppressing dissolution and release of toxic Ag+ ions in the growth medium. The presence of biochar at least decreased 2-fold tissue contents of Ag even at highest AgNPs (1000 mg L-1) concentration. These finding suggested that biochar derived from waste biomass resources can be used effectively to prevent the bioaccumulation and subsequent trophic level transfer of emerging Ag nano-pollutant in the environment.


Assuntos
Carvão Vegetal/química , Nanopartículas Metálicas/toxicidade , Oryza/crescimento & desenvolvimento , Fotossíntese/efeitos dos fármacos , Prata/toxicidade , Disponibilidade Biológica , Biomassa , Clorofila/metabolismo , Oryza/metabolismo , Prata/metabolismo , Solo/química
20.
Environ Sci Pollut Res Int ; 26(16): 16040-16052, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30968299

RESUMO

Yellow-lupin (Lupinus luteus L.) was grown on soils contaminated with heavy metals during two parallel studies. In the first one, the soil was contaminated by industrial activities whereas, in the second one, the soil was artificially contaminated with a single metal including Cd, Pb, Zn, Ni (in nitrate form), and Ag (in nitrate and nanoparticles form). The study was performed to assess a plant's response to contamination including its antioxidative response and molecular mechanisms involved in metal detoxification through the expression level of metallothioneins (MTs). Overall, the study provided insights into identification and validation of housekeeping genes (HKG) in L. luteus under exposure to metal stress and showed the effects of selected heavy metals and silver nanoparticles on the expression of metallothioneins, the activity of guaiacol peroxidase (GPX) and bioaccumulation of metals in leaves of L. luteus. As such, HKG validation using BestKeeper, NormFinder, and geNorm software allowed for the selection of four most stable reference genes in a context metal contamination for the selected plant. Moreover, a significant increase in the expression levels of MT was observed in plants grown under heavy metal stress and none on plants grown on 25 mg kg-1 of silver nanoparticles. Also, the GPX activity and MT expression showed statistically significant changes between different conditions and doses which means that they can be used as highly sensitive stress markers for planning the phytoremediation process on a large scale.


Assuntos
Lupinus/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Metalotioneína/metabolismo , Metais Pesados/farmacocinética , Poluentes do Solo/farmacocinética , Antioxidantes/metabolismo , Ecotoxicologia/métodos , Biomarcadores Ambientais/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lupinus/genética , Lupinus/metabolismo , Metalotioneína/genética , Metais Pesados/toxicidade , Peroxidase/genética , Peroxidase/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Prata/farmacocinética , Prata/toxicidade , Solo/química , Poluentes do Solo/toxicidade
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