Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Cell Biochem Biophys ; 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38802601

RESUMO

The soluble-to-toxic transformation of intrinsically disordered amyloidogenic proteins such as amyloid beta (Aß), α-synuclein, mutant Huntingtin Protein (mHTT) and islet amyloid polypeptide (IAPP) among others are associated with disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and Type 2 Diabetes (T2D), respectively. The dissolution of mature fibrils and toxic amyloidogenic intermediates, including oligomers, continues to be the pinnacle in the treatment of neurodegenerative disorders. Yet, methods to effectively and quantitatively report on the interconversion between amyloid monomers, oligomers and mature fibrils fall short. Here we describe a simplified method that implements the use of gel electrophoresis to address the transformation between soluble monomeric amyloid proteins and mature amyloid fibrils. The technique implements an optimized but well-known, simple, inexpensive, and quantitative assessment previously used to assess the oligomerization of amyloid monomers and subsequent amyloid fibrils. This method facilitates the screening of small molecules that disintegrate oligomers and fibrils into monomers, dimers, and trimers and/or retain amyloid proteins in their monomeric forms. Most importantly, our optimized method diminishes existing barriers associated with existing (alternative) techniques to evaluate fibril formation and intervention.

2.
Res Sq ; 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38585783

RESUMO

The soluble-to-toxic transformation of intrinsically disordered amyloidogenic proteins such as amyloid beta (Aß), α-synuclein, mutant Huntingtin Protein (mHTT) and islet amyloid polypeptide (IAPP) among others is associated with disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and Type 2 Diabetes (T2D), respectively. The dissolution of mature fibrils and toxic amyloidogenic intermediates including oligomers continues to be the pinnacle in the treatment of neurodegenerative disorders. Yet, methods to effectively, and quantitatively, report on the interconversion between amyloid monomers, oligomers and mature fibrils fall short. Here we describe a simplified method that implements the use of gel electrophoresis to address the transformation between soluble monomeric amyloid proteins and mature amyloid fibrils. The technique implements an optimized but well-known, simple, inexpensive and quantitative assessment previously used to assess the oligomerization of amyloid monomers and subsequent amyloid fibrils. This method facilitates the screening of small molecules that disintegrate oligomers and fibrils into monomers, dimers, and trimers and/or retain amyloid proteins in their monomeric forms. Most importantly, our optimized method diminishes existing barriers associated with existing (alternative) techniques to evaluate fibril formation and intervention.

3.
Chemosphere ; 352: 141248, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38280643

RESUMO

Anthracene belongs to the polycyclic aromatic hydrocarbon (PAH) consisting of benzene rings, unusually highly stable through more π-electrons and localized π-bond in entire rings. Aqueous-phase anthracene adsorption using carbon-based materials such as biochar is ineffective. In this paper, carbon dots (CDs) derived from the acid treatment of coconut shell biochar (CDs/MCSB) decorated with chitosan (CS) are successfully synthesized and applied for anthracene removal from aqueous solutions. The h-CDs/MCSB exhibited fast adsorption of anthracene with significant sorption capacity (Qmax = 49.26 mg g-1) with 95 % removal efficiency at 60 min. The study suggested chemisorption dominated monolayer anthracene adsorption onto h-CDs/MCSB, where a significant role was played by ion-exchange. Density Functional Theory (DFT) suggested the anthracene adsorption was dominated by the electrostatic interactions and delocalized electron, induced by higher polarizability of functional groups on the surface of hybrid CDs/MCSB assisted by chitosan (h-CDs/MCSB). In addition, the aromatic structure of CDs/MCSB and high polarizability of functional groups provided the strong interactions between benzene rings of anthracene and hybrid adsorbent-assisted multiple π-bond through delocalized π-bond and polarization-induced H-bond interactions. The presence of carboxylic and sulfonic groups on the CDs/MCSB surface also contributed to the effective adsorption of anthracene was confirmed by the fluorescence spectra. The results showed that the hybrid adsorbent was an effective material for removing PAHs, usually difficult to remove from water owing to the presence of benzene rings in their structures. Further, consistency in the DFT results suggested the outstanding binding capacity with the anthracene molecules with h-CDs/MCSB.


Assuntos
Quitosana , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Carbono , Adsorção , Água , Benzeno , Carvão Vegetal/química , Antracenos , Poluentes Químicos da Água/química , Cinética
4.
Environ Sci Process Impacts ; 25(12): 2110-2124, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-37916297

RESUMO

Applications of metal-based nanomaterials for the remediation of heavy metal (HM) contaminated environments are of great importance. The ability of metal oxide-based carbon aerogel composite to immobilize HMs in multi-metal contaminated soils has not yet been investigated, particularly under acidic conditions. Herein, we investigate the performance of metal oxides (Sr0.7 Mn0.3 Co0.5 Fe0.5O3-δ)-based carbon aerogel composite (MO-CAg) compared with coconut coil fiber biochar (CCFB) and carbon aerogel (CAg) for Cd and Pb immobilization in contaminated soil. The MO-CAg, applied at 2% (w/w), significantly decreased Pb leaching by 67-75% and Cd by 60-65%, CAg decreased Cd by 54% and Pb by 46%, while biochar decreased Cd by 40-44% and Pb by 43%. The addition of MO-CAg altered Cd and Pb geochemical fractions by increasing their residual fraction, i.e., stabilized both metals compared to the control. This presents a comprehensive elaboration on the probable reaction interactions between the MO-Cag and heavy metals, including a combination of (co)precipitation, and reduction-oxidation as the predominant mechanisms of metal stabilization with MO-CAg. Moreover, MO-CAg increased Pb and Cd stabilization in soils by strengthening the bonding between metal oxides and Cd/Pb. By imbedding MO into the CAg, in MO-CAg, the immobilization of Cd(II) and Pb(II) occurred through inner-sphere complexation, while with CCFB and CAg metals, immobilization occurred through outer-sphere complexation. MO-CAg is a promising and highly efficient material that could be recommended for the remediation of Cd- and Pb-contaminated soils in subsequent studies.


Assuntos
Metais Pesados , Poluentes do Solo , Cádmio/análise , Chumbo , Poluentes do Solo/análise , Metais Pesados/análise , Carvão Vegetal , Carbono , Óxidos , Solo
5.
RSC Adv ; 13(21): 14110-14118, 2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37179991

RESUMO

Different concentrations of titanium oxide nanoparticles (TiO2NPs) have been frequently reported in treated wastewater used for the irrigation of crops. Luteolin is a susceptive anticancer flavonoid in many crops and rare medicinal plants that can be affected by exposure to TiO2NPs. This study investigates the potential transformation of pure luteolin in exposure to TiO2NP-containing water. In an in vitro system, three replicates of 5 mg L-1 of pure luteolin were exposed to TiO2NPs (0, 25, 50, 100 ppm). After 48 h exposure, the samples were extensively analyzed by Raman spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, and dynamic light scattering (DLS). A positive correlation was found between TiO2NPs concentrations and the structural alteration of luteolin content, where over 20% of luteolin structure was allegedly altered in the presence of 100 ppm TiO2NPs. The increase of NPs diameter (∼70 nm) and dominant peaks in Raman spectra revealed that luteolin was adsorbed onto the TiO2NPs surface. Further, the second-order derivative analysis confirmed the transformation of luteolin upon exposure to TiO2NPs. This study provides fundamental insight into agricultural safety measures when exposed to air or water-borne TiO2NPs.

6.
Int J Phytoremediation ; 25(1): 98-105, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35452585

RESUMO

Nickel (Ni) is one of the most toxic metals in human health. Its bioaccumulation in gluten-free crops limits the progressing demand of safe foods for allergic people to gluten. Nanoparticles have shown promising results in enhancing the crop yield and reducing the risk of heavy metal uptake. However, their nanotoxicity has been raised environmental concerns. This study investigated the environmental behavior of Ni (II) with the co-presence of Zinc Oxide Nanoparticles (ZnO-NPs) in sorghum bicolor. The plants were exposed to different treatments of Ni, ZnO-NPs, or their coexistence. The uptake experiments were carried out within nine treatments consisting of 1 or 5 ppm Ni alone or in coexistence with 50 or 100 ppm ZnO-NPs. The physiological impacts on plants as potential fingerprints for nanotoxicity were recorded and assessed in a phenotypic spectrum. The total Ni or Zn contents were quantified using atomic absorption. NPs significantly altered the bioavailability of Ni. The results revealed that at 5 ppm Ni contamination, 50 and 100 ZnO-NPs significantly reduced the Ni uptake by ∼43% and 47%, respectively. Further, the results showed at 50 ppm NPs, the phytotoxicity effects of both Ni and NPs may reduce, leading to higher plant dry biomass yield.Novelty statement Characterization of zinc oxide nanotoxicity threshold by developing a phenotypic spectrum. Also, the study revealed the phytoremediation potential of ZnO nanoparticle in mitigating the nickel uptake in a gluten-free crop (sorghum bicolor).


Assuntos
Nanopartículas Metálicas , Metais Pesados , Nanopartículas , Poluentes do Solo , Sorghum , Óxido de Zinco , Humanos , Óxido de Zinco/toxicidade , Níquel/toxicidade , Poluentes do Solo/análise , Biodegradação Ambiental , Nanopartículas Metálicas/toxicidade , Nanopartículas/toxicidade , Raízes de Plantas/química
7.
Environ Sci Technol ; 56(4): 2455-2465, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35099180

RESUMO

Per- and polyfluoroalkyl substances (PFASs) are a large family of thousands of chemicals, many of which have been identified using nontargeted time-of-flight and Orbitrap mass spectrometry methods. Comprehensive characterization of complex PFAS mixtures is critical to assess their environmental transport, transformation, exposure, and uptake. Because 21 tesla (T) Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) offers the highest available mass resolving power and sub-ppm mass errors across a wide molecular weight range, we developed a nontargeted 21 T FT-ICR MS method to screen for PFASs in an aqueous film-forming foam (AFFF) using suspect screening, a targeted formula database (C, H, Cl, F, N, O, P, S; ≤865 Da), isotopologues, and Kendrick-analogous mass difference networks (KAMDNs). False-positive PFAS identifications in a natural organic matter (NOM) sample, which served as the negative control, suggested that a minimum length of 3 should be imposed when annotating CF2-homologous series with positive mass defects. We putatively identified 163 known PFASs during suspect screening, as well as 134 novel PFASs during nontargeted screening, including a suspected polyethoxylated perfluoroalkane sulfonamide series. This study shows that 21 T FT-ICR MS analysis can provide unique insights into complex PFAS composition and expand our understanding of PFAS chemistries in impacted matrices.


Assuntos
Fluorocarbonos , Poluentes Químicos da Água , Fluorocarbonos/análise , Espectrometria de Massas , Água , Poluentes Químicos da Água/análise
8.
Sci Total Environ ; 806(Pt 3): 151222, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34715233

RESUMO

The extensive application of titanium dioxide nanoparticles (TiO2NPs) in agro-industrial practices leads to their high accumulation in the environment or agricultural soils. However, their threshold and ecotoxicological impacts on plants are still poorly understood. In this study, the hormetic effects of TiO2NPs at a concentration range of 0-2500 mg/L on the growth, and biochemical and physiological behaviors of Nigella arvensis in a hydroponic system were examined for three weeks. The translocation of TiO2NPs in plant tissues was characterized through scanning and transmission electron microscopy (SEM and TEM). The bioaccumulation of total titanium (Ti) was quantified by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Briefly, the elongation of roots and shoots and the total biomass growth were significantly promoted at 100 mg/L TiO2NPs. As the results indicated, TiO2NPs had a hormesis effect on the proline content, i.e., a stimulating effect at the low concentrations of 50 and 100 mg/L and an inhibiting effect in the highest concentration of 2500 mg/L. A biphasic dose-response was observed against TiO2NPs in shoot soluble sugar and protein contents. The inhibitory effects were detected at ≥1000 mg/L TiO2NPs, where the synthesis of chlorophylls and carotenoid was reduced. At 1000 mg/ L, TiO2NPs significantly promoted the cellular H2O2 generation, and increased the activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT). Furthermore, it enhanced the total antioxidant content (TAC), total iridoid content (TIC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. Overall, the study revealed the physiological and biochemical alterations in a medicinal plant affected by TiO2NPs, which can help to use these NPs beneficially by eliminating their harmful effects.


Assuntos
Nanopartículas , Nigella , Antioxidantes , Hormese , Peróxido de Hidrogênio , Nanopartículas/toxicidade , Titânio/toxicidade
9.
Environ Monit Assess ; 193(12): 800, 2021 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-34773492

RESUMO

Recent advances in nano-enabled agriculture raised hope in the efficient delivery of bioactive minerals to crops. Nanocomposites (NCPs) are promising technologies in soil fertilizing without compromising environmental contamination. NCPs have shown positive impacts on plant growth and nanofortification of crop yield. Here, we have synthesized a nanocomposite that could induce the positive impacts of the Mn, Fe, and Ce nanoparticles for the crops. The NCPs were extensively characterized and applied at three levels 100, 250, and 500 ppm on T. aestivum L. seeds for 10 days. The germination, biomass, and elongation have been measured as the main physiological parameters of the plant. The total content of chlorophyll, carotenoids, and enzymatic and non-enzymatic antioxidant in response to NCPs was quantified. The concentration of essential minerals (iron and manganese) and the non-essential element of cerium in roots and shoots were quantified using inductively coupled plasma mass spectrometry (ICP-MS). Briefly, the germination rate increased by 15%; total chlorophyll and carotenoid were augmented by 61% and 38%, respectively, in exposure to 100 ppm. Higher uptake of micronutrient Fe and Mn in shoots and led to higher yield production by 14% and 18%, respectively. A positive correlation between the increasing dose of NCPs and the total content of the superoxide dismutase (SOD), and peroxidase (POD) were quantified. Overall, the results indicate the high potential of NCPs applications in agricultural practice.


Assuntos
Nanocompostos , Poluentes do Solo , Clorofila , Monitoramento Ambiental , Compostos Férricos , Fotossíntese , Raízes de Plantas , Triticum
10.
Sci Total Environ ; 771: 145427, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33736164

RESUMO

Per- and polyfluoroalkyl substances (PFASs) are a heterogeneous group of persistent organic pollutants that have been detected in various environmental compartments around the globe. Emerging research has revealed the preferential accumulation of PFASs in shallow soil horizons, particularly at sites impacted by firefighting activities, agricultural applications, and atmospheric deposition. Once in the vadose zone, PFASs can sorb to soil, accumulate at interfaces, become volatilized, be taken up in biota, or leach to the underlying aquifer. At the same time, polyfluorinated precursor species may transform into highly recalcitrant perfluoroalkyl acids, changing their chemical identity and thus transport behavior along the way. In this review, we critically discuss the current state of the knowledge and aim to interconnect the complex processes that control the fate and transport of PFASs in the vadose zone. Furthermore, we identify key challenges and future research needs. Consequently, this review may serve as an interdisciplinary guide for the risk assessment and management of PFAS-contaminated sites.

11.
Front Plant Sci ; 12: 808141, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35095979

RESUMO

The development of reproductive components in plant species is susceptible to environmental stresses. The extensive application of zinc oxide nanoparticles (nZnO) in various agro-industrial processes has jeopardized the performance and functionality of plants. To understand the response of the developmental (gametogenesis and sporogenesis) processes to nanoparticles (NPs) exposure, the aerial application of nZnO and their ionic counterpart of ZnSO4 at four different levels were examined on bean plants (Phaseolus vulgaris) before the flowering stage. To evaluate the mentioned processes, briefly, flowers in multiple sizes were fixed in paraffin, followed by sectioning and optical analysis. The possibility of alteration in reproductive cells was thoroughly analyzed using both light and electron microscopes. Overall, our results revealed the histological defects in male and female reproductive systems of mature plants depend on NPs levels. Furthermore, NPs caused tapetum abnormalities, aberrations in carbohydrate accumulation, and apoptosis. The nZnO induced abnormal alterations right after meiosis and partly hindered the microspore development, leading to infertile pollens. The seed yield and dry weight were reduced to 70 and 82% at 2,000 mg L-1 nZnO foliar exposure, respectively. The sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis pattern showed the increased expression of two proteins at the molecular weight of 28 and 42 kDa at various concentrations of nZnO and ZnSO4. Overall, our results provided novel insights into the negative effect of nano-scaled Zn on the differential mechanism involved in the reproductive stage of the plants compared with salt form.

12.
Environ Monit Assess ; 192(6): 344, 2020 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385746

RESUMO

Polar Organic Chemical Integrative Samplers (POCIS) with two supporting polyethersulfone (PES) membranes and a strong adsorbent in between are frequently used to determine the concentrations of polar organic contaminants in the aqueous environment. The solute transfer rate (SRs) through PES is a key parameter affecting the critical membrane/water partitioning coefficient (Rmw) of polar organic molecules, which in turn affects the concentration of these molecules on the adsorbent and the accuracy of POCIS measurement. However, information on SRs and Rmw in the literature is very limited. Prolonged use of POCIS in the measurement of organic compounds may lead to membrane fouling by the retained organic compounds. The relationship between the properties of the polar organic compounds and their different accumulation behaviors in POCIS is not yet clear. This study aimed to measuring the solute transfer rate of four polar organic compounds (atrazine, caffeine, ibuprofen, and atenolol). The results indicated that atrazine had the highest SR of 0.49 mL day-1. Both caffeine and atenolol had an SRs of approximately 0.3 mL day-1. Ibuprofen had the lowest SR of 0.23 mL day-1. The results further revealed that the tendency of the organic solutes to adsorb onto interstitial spaces of the PES polymer was associated with their hydrophobicity and molecular structures.


Assuntos
Monitoramento Ambiental , Polímeros , Sulfonas , Poluentes Químicos da Água , Compostos Orgânicos
13.
Ecotoxicol Environ Saf ; 191: 110177, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31958627

RESUMO

Advances in large hydroponic production of leafy greens, easy adoption in urban agriculture, and large leaf surface area of many leafy greens, greatly increase their exposure to heavy metals and nanoparticles. Cadmium (Cd) and lead (Pb) are two highly toxic heavy metals, which threaten the health of humans and livestock even at trace levels. These heavy metals may be taken up by plant roots through the protein transporters used for essential minerals such as iron (Fe2+) and copper (Cu2+). Previous studies have shown that some metallic nanoparticles affect the performance of protein transporters and modify the plant uptake of co-existing heavy metal ions. This study aims to understand the role of zinc oxide nanoparticles (ZnONPs) in the uptake pattern of Cd and Pb and two key micronutrients of iron and copper in edible tissues of three leafy green species including spinach (Spinaciae oleracea), parsley (Petroselinum sativum) and cilantro (Coriandrum sativum). Pre-grown plant seedlings in soil (containing Cu and Fe) were transplanted to a hydroponic system (1/4th Hoagland solution) for 7 days as a transition, and then were exposed to four treatments in deionized water (1.0 mg L-1 Cd2++100.0 mg L-1 Pb2+, 1.0 mg L-1 Cd2++100.0 mg L-1 Pb2+ + 100 mg L-1 ZnONPs, 100 mg L-1 ZnO-ENPs and a control with no chemical exposure) for additional two weeks. At termination, shoots were gently separated from the roots, and the concentrations of Pb, Cd, Fe, Zn, and Cu in all plant tissues were quantified by inductively coupled plasma-mass spectrometry (ICP-MS). The results revealed that ZnONPs mitigated the uptake of both heavy metals in roots. The translocation of heavy metals was similar in the edible tissues of three species. The response of three leafy greens to the co-exposure of heavy metals and ZnONPs was different in Cu and Fe accumulation in edible tissues. Fe concentration in edible tissues in the co-exposed plants was increased in spinach (+10%) and cilantro (+9%) but decreased in parsley (-8%) compared to controls, while the Cu level in edible tissues increased in all three species following the order of cilantro (+8%)> spinach (+4%)> parsley (+1.5%).


Assuntos
Produtos Agrícolas/metabolismo , Metais Pesados/metabolismo , Nutrientes/metabolismo , Poluentes Químicos da Água/metabolismo , Óxido de Zinco/metabolismo , Disponibilidade Biológica , Cádmio/metabolismo , Cobre/metabolismo , Produtos Agrícolas/classificação , Produtos Agrícolas/crescimento & desenvolvimento , Hidroponia , Ferro/metabolismo , Chumbo/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Especificidade da Espécie , Óxido de Zinco/química
14.
Int J Phytoremediation ; 22(3): 305-312, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31468994

RESUMO

Engineered nanoparticles (ENPs) often interact closely with coexisting environmental pollutants; however, the effect of their surface properties on such interactions in a plant system has not been examined. This study investigated the roles of ENP surface charge and growth media chemistry on the mutual effects of cerium oxide nanoparticles (CeO2NPs) and cadmium (Cd) on their plant uptake and accumulation in a hydroponic system. Soybean seedlings were exposed to five nanoparticle/Cd treatments including: 100 mg L-1 CeO2NPs(+); 100 mg L-1 CeO2NPs(-); 100 mg L-1 CeO2NPs(+) + 1 mg L-1 Cd; 100 mg L-1 CeO2NPs(-) + 1 mg L-1 Cd; and 1 mg L-1 Cd only, in the presence or absence of 15 mg L-1 phosphorous in the form of phosphate. After 4 days of exposure, concentrations of Cd and Ce in plant tissues were quantified by inductively coupled plasma-mass spectrometry. Roots exposed to CeO2NPs(+) contained 87% higher Ce than plants exposed to CeO2NPs(-). Phosphate significantly increased the root concentration of Ce by 61% and 66% exposed to CeO2NPs(+) and CeO2NPs(-), respectively. The mutual effect of CeO2NPs and Cd was also affected by phosphate, and the net effect of phosphate depended upon the surface charge of CeO2NPs.


Assuntos
Glycine max , Nanopartículas , Biodegradação Ambiental , Cádmio , Cério , Fosfatos , Raízes de Plantas
15.
Plant Physiol Biochem ; 135: 160-166, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30553137

RESUMO

A greenhouse study comparing the physiological responses and uptake of coffee (Coffea arabica L.) plants to foliar applications of zinc sulfate (ZnSO4) and zinc nano-fertilizer (ZnO NPs) was conducted with the aim to understand their effects on plant physiology. One-year old coffee plants were grown in greenhouse conditions and treated with two foliar applications of 10 mg/L of Zn as either zinc sulfate monohydrate (ZnSO4 ‧ H2O) or zinc oxide nanoparticle (ZnO NPs 20% w/t) and compared to untreated control plants over the course of 45 days. ZnO NPs positively affected the fresh weight and dry weight (FW and DW) of roots and leaves, increasing the FW by 37% (root) and 95% (leaves) when compared to control. The DW increase was 28%, 85%, and 20% in roots, stems, and leaves, respectively. The net photosynthetic rate increased 55% in response to ZnO NPs treatment at the end of experiment when compared to control. ZnO NPs-treated leaves contained significantly higher amounts of Zn (1267.1 ±â€¯367.2 mg/kg DW) when compared to ZnSO4-treated plants (344.1 ±â€¯106.2 mg/kg DW), while control plants had the lowest Zn content in the leaf tissue (53.6 ±â€¯18.9 mg/kg DW). X-ray micro-analyses maps demonstrated the increased penetrance of ZnO NPs in coffee leaf tissue. Overall, ZnO NPs had a more positive impact on coffee growth and physiology than conventional Zn salts, which was most likely due to their increased ability to be absorbed by the leaf. These results indicate that the application of ZnO NPs could be considered for coffee systems to improve fruit set and quality, especially in areas where Zn deficiency is high.


Assuntos
Coffea/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Sulfato de Zinco/farmacologia , Zinco/farmacologia , Clorofila/metabolismo , Coffea/crescimento & desenvolvimento , Coffea/fisiologia , Nanopartículas Metálicas , Microscopia Eletrônica de Varredura , Fotossíntese/efeitos dos fármacos , Folhas de Planta/ultraestrutura , Transpiração Vegetal/efeitos dos fármacos , Zinco/administração & dosagem , Zinco/metabolismo , Sulfato de Zinco/administração & dosagem , Sulfato de Zinco/metabolismo
16.
Environ Sci Technol ; 52(17): 10040-10047, 2018 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-30075083

RESUMO

The accumulation of arsenic (As) in rice grains depends greatly on the redox chemistry in rice rhizosphere. Intentional or accidental introduction of strong oxidizing or reducing agents, such as metallic engineered nanoparticles (ENPs) into the plant-soil ecosystem, can change As speciation and plant uptake. However, investigation on the effects of ENPs on plant uptake of co-occurring redox sensitive heavy metals and their speciation in plant tissues is scarce. We investigated the mutual effects of two commonly encountered ENPs, cerium oxide nanoparticles (CeO2 NPs) and zinc oxide nanoparticles (ZnO NPs), and two inorganic species of As on their uptake and accumulation in rice seedlings in a hydroponic system. Rice seedlings were exposed to different combinations of 1 mg/L of As(III) or As(V) and 100 mg/L of CeO2 NPs and ZnO NPs for 6 days about 40 days after germination. ZnO NPs significantly reduced the accumulation of As(III) in rice roots by 88.1 and 96.7% and in rice shoots by 71.4 and 77.4% when the initial As was supplied as As(III) and As(V), respectively. ZnO NPs also reduced As(V) in rice roots by 68.3 and 52.3% when the As was provided as As(III) and As(V), respectively. However, the As(V) in rice shoots was unaffected by ZnO NPs regardless of the initial oxidation state of As. Neither the total As nor the individual species of As in rice tissues was significantly changed by CeO2 NPs. The co-presence of As(III) and As(V) increased Ce in rice shoots by 6.5 and 2.3 times but did not affect plant uptake of Zn. The results confirmed the active interactions between ENPs and coexisting inorganic As species, and the extent of their interactions depends on the properties of ENPs as well as the initial oxidation state of As.


Assuntos
Arsênio , Cério , Oryza , Óxido de Zinco , Ecossistema , Hidroponia , Raízes de Plantas
18.
Environ Res ; 148: 273-276, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27088731

RESUMO

Sunscreen products and some personal care products contain the Ultraviolet (UV) chemical filters, which are entering the surface water. Public concerns about secondary effects of these compounds are growing because of the contamination of the aquatic environment that may reach to potentially toxic concentration levels. This article highlights the reaction of certain UV filters with hypochlorite disinfectant in the presence of sunlight. Due to urbanization and industrialization, use of outdoor plastic swimming pools is increasing. The relatively smaller volume of these pools compared to larger pools may increase the concentration of the UV filters in the pool and their potential interactions with materials of human origin (urine, sweat, cosmetics, skin cells, and hair) to the levels of toxicity concerns for children through the creation of disinfection by products (DBP). Based on our analysis, the minimum concentration levels of 2.85, 1.9, 1.78 and 0.95g/L, respectively, for EHMC, OC, 4-MBC and BP3 UV filters in children pools are predicted. Therefore, this article calls for an urgent investigation of potential toxic effects of the UV filters, the creation of DBPs and their subsequent impacts on human health.


Assuntos
Protetores Solares/análise , Protetores Solares/química , Piscinas , Acrilatos/análise , Acrilatos/química , Adulto , Benzofenonas/análise , Benzofenonas/química , Cânfora/análogos & derivados , Cânfora/análise , Cânfora/química , Criança , Pré-Escolar , Cloro/química , Cinamatos/análise , Cinamatos/química , Desinfetantes/química , Desinfecção , Feminino , Halogenação , Humanos , Masculino , Urbanização
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA