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1.
Ecotoxicol Environ Saf ; 203: 111001, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888585

RESUMO

Environmental nanomaterials contamination is a great concern for organisms including human. Copper oxide nanoparticles (CuO NPs) are widely used in a huge range of applications which might pose potential risk to organisms. This study investigated the in vivo transgenerational toxicity on development and reproduction with parental CuO NPs exposure in the nematode Caenorhabditis elegans. The results showed that CuO NPs (150 mg/L) significantly reduced the body length of parental C. elegans (P0). Only about 1 mg/L Cu2+ (~0.73%) were detected from 150 mg/L CuO NPs in 0.5X K-medium after 48 h. In transgenerational assays, CuO NPs (150 mg/L) parental exposure significantly induced developmental and reproductive toxicity in non-exposed C. elegans progeny (CuO NPs free) on body length (F1) and brood size (F1 and F2), respectively. In contrast, parental exposure to Cu2+ (1 mg/L) did not cause transgenerational toxicity on growth and reproduction. This suggests that the transgenerational toxicity was mostly attributed to the particulate form of CuO NPs. Moreover, qRT-PCR results showed that the mRNA levels of met-2 and spr-5 genes were significantly decreased at P0 and F1 upon only maternal exposure to CuO NPs (150 mg/L), suggesting the observed transgenerational toxicity was associated with possible epigenetic regulation in C. elegans.


Assuntos
Caenorhabditis elegans/efeitos dos fármacos , Cobre/toxicidade , Epigênese Genética/efeitos dos fármacos , Nanopartículas/toxicidade , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/fisiologia , Feminino , Humanos , Exposição Materna/efeitos adversos , Reprodução/efeitos dos fármacos , Reprodução/genética
2.
Ecotoxicol Environ Saf ; 205: 111334, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32961486

RESUMO

In order to investigate and model toxicity and interactions between metals in mixtures, inhibition of wheat root elongation in response to additions of single-metals of copper (Cu), zinc (Zn), and nickel (Ni) and of binary mixed-metal combinations of Cu-Ni and Zn-Ni was tested, using water culture experiments under different Mg concentrations and pH values. A biotic ligand model (BLM) of single-metal Cu, Zn, and Ni was established. The results showed that the toxicity of Cu, Zn or Ni in isolation decreased with increasing Mg concentration whereas the effects of pH on Cu, Zn, or Ni toxicity were related not only to free Cu2+, Zn2+, and Ni2+ concentrations, but also to inorganic metal complexes. In binary mixtures, the two metals in the Cu-Ni mixture showed a weakly antagonistic effect, whereas the two metals in the Zn-Ni mixture showed greater antagonism. Using data from single-metal Cu, Zn, and Ni BLMs, combined with the toxicity index and the overall amounts of metal ions bound to the biotic ligands, one simple model was developed. This model consisted of the toxic unit (TUM, no competition included) and two extended BLMs, BLM-TUf (f as a function of TU, including competition between Mg2+ and metal ions) and BLM-fmix (including the competition between Mg2+ and metal ions, as well as between free metal ions). They were then used to predict the joint toxicity of Cu-Ni and Zn-Ni binary mixtures to wheat. Both of the extended BLMs could provide more accurate predictions of toxic effects of Cu-Ni and Zn-Ni than TUM. BLM-fmix performed best for the Zn-Ni binary mixture (r2 = 0.93; root-mean-square error, RMSE = 9.87). On the other hand, for the Cu-Ni mixture, the predictive effect based on BLM-TUf (r2 = 0.93; RMSE = 9.60) was similar to that of BLM-fmix (r2 = 0.93; RMSE = 9.56). The results provide a theoretical basis for the evaluation and remediation of soils contaminated with mixtures of heavy metals.


Assuntos
Cobre/toxicidade , Modelos Biológicos , Níquel/toxicidade , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Zinco/toxicidade , Relação Dose-Resposta a Droga , Antagonismo de Drogas , Ligantes , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Triticum/crescimento & desenvolvimento
3.
Ecotoxicol Environ Saf ; 205: 111089, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32810645

RESUMO

Early molecular events after the exposure of heavy metals, such as aberrant DNA methylation, suggest that DNA methylation was important in regulating physiological processes for animals and accordingly could be used as environmental biomarkers. In the present study, we found that copper (Cu) exposure increased lipid content and induced the DNA hypermethylation at the whole genome level. Especially, Cu induced hypermethylation of glucose-regulated protein 78 (grp78) and peroxisome proliferator-activated receptor gamma coactivator-1α (pgc1α). CCAAT/enhancer binding protein α (C/EBPα) could bind to the methylated sequence of grp78, whereas C/EBPß could not bind to the methylated sequence of grp78. These synergistically influenced grp78 expression and increased lipogenesis. In contrast, DNA methylation of PGC1α blocked the specific protein 1 (SP1) binding and interfered mitochondrial function. Moreover, Cu increased reactive oxygen species (ROS) production, activated endoplasmic reticulum (ER) stress and damaged mitochondrial function, and accordingly increased lipid deposition. Notably, we found a new toxicological mechanism for Cu-induced lipid deposition at DNA methylation level. The measurement of DNA methylation facilitated the use of these epigenetic biomarkers for the evaluation of environmental risk.


Assuntos
Carpas/fisiologia , Cobre/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Carpas/metabolismo , Cobre/metabolismo , Estresse do Retículo Endoplasmático , Glucose/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Lipídeos , Metilação , Mitocôndrias/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Ativação Transcricional , Regulação para Cima
4.
Ecotoxicol Environ Saf ; 205: 111163, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32836159

RESUMO

Arthrobacter sp. JQ-1 can completely degrade 500 mg/L of DEHP within 3 days. The minimum inhibitory concentrations (MICs) of Cu2+ could reach 1.56 mM, however, 5.0 mg/L Cu2+ apparently inhibited DEHP degradation and bacterial growth. Consequently, JQ-1 was exposed to the DEHP-copper environment to verify the toxicity mechanism based on the physiological responses of cellular multiple interfaces (cellular surface, membrane and intracellular characteristics). The results showed the combination of 500 mg/L DEHP and 5.0 mg/L Cu2+ significantly decreased cell surface hydrophobicity (CSH) and the absolute value of zeta potential, which implied the bioavailability of DEHP was decreased. The cellular surface changes were mainly due to the interaction between Cu2+ and some functional groups (CH2, CH3, aromatic rings, and amide). The weakened proton-motive force (PMF) across the plasma membrane may interfere the formation and utilization of energy, which is not conducive to the repair process of cellular damages. In this study, Non-invasive micro-test technology (NMT) was applied to the research of combined toxicity of DEHP and heavy metal ions for the first time. DEHP-copper intensified K+ efflux and Ca2+ influx across the plasma membrane, which disturbed ion homeostasis of K+ and Ca2+ and might induce apoptosis and further inhibit DEHP degradation. The decline of intracellular esterase activity indicated that the metabolic capacity is apparently restrained. This study enhances our understanding of cellular different interface processes responding to combined pollutants.


Assuntos
Arthrobacter/efeitos dos fármacos , Cobre/toxicidade , Dietilexilftalato/toxicidade , Poluentes do Solo/toxicidade , Arthrobacter/metabolismo , Arthrobacter/ultraestrutura , Biodegradação Ambiental , Cálcio/metabolismo , Cobre/metabolismo , Dietilexilftalato/metabolismo , Sinergismo Farmacológico , Potássio/metabolismo , Solo/química , Microbiologia do Solo , Poluentes do Solo/metabolismo
5.
Ecotoxicol Environ Saf ; 205: 111175, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32836161

RESUMO

Mangroves are susceptible to contamination due to their proximity to shores and human activities. Exposure to excessive trace metals can disturb their physiological functions and may eventually lead to death. Rhizophora mucronata is a common species growing in the mangrove forests of Thailand. Previous studies have shown that seedlings of R. mucronata are tolerant of trace metal and that they accumulate a large metal content in their root tissue. However, knowledge of their tolerance mechanisms is still lacking. To elicit the role of metal detoxification and sequestration by phytochelatins (PC) in the roots of R. mucronata seedlings, the impacts of Cu and Zn exposure were assessed on 1) physiological characteristics 2) the concentration of glutathione (GSH), a precursor of PC and 3) the level of the transcripts encoding phytochelatin synthase (PCS), the key enzyme for PC biosynthesis. Seedlings of R. mucronata were exposed to Cu and Zn in a hydroponic experiment (200 mg Cu or Zn/L in 1/4× Hoagland solution containing 8‰ NaCl, single addition). We found that both trace metals were largely accumulated in the roots. Only Cu-treated seedlings showed a decrease in the photosynthetic efficiency, in line with observed toxicity symptoms (i.e. bent stems and slight wilting of leaves). Metal accumulation, however, did not induce oxidative stress in the roots as indicated by similar level of total reactive species and lipid peroxidation across treatments. The GSH content in the roots exposed to Cu was significantly reduced while no change was observed in Zn-exposed roots. Coordinated semi-quantitative PCR and RT-qPCR revealed pcs down-regulation in Cu-treated roots, whereas Zn-treated roots showed a down-regulation on day 1 and a subsequent recovery on day 5. Failure of detoxification and sequestration of excess Cu due to GSH limitation and down-regulation of pcs may lead to the phytotoxic effects observed in Cu-treated plants. Our results suggest that both GSH and PC play an important role in trace metal tolerance in R. mucronata seedlings.


Assuntos
Aminoaciltransferases/genética , Cobre/toxicidade , Glutationa/metabolismo , Rhizophoraceae/efeitos dos fármacos , Oligoelementos/metabolismo , Zinco/toxicidade , Adaptação Fisiológica/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Rhizophoraceae/genética , Rhizophoraceae/metabolismo , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/metabolismo
6.
Toxicon ; 186: 151-159, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32798503

RESUMO

Heavy metals and microcystins commonly co-exist in water bodies with cyanobacteria, and have been shown to affect aquatic plants. However, their combined effects remain largely unknown. In this study, the toxic effects of copper (Cu) and cadmium (Cd) on Ceratophyllum demersum L. were characterized in the presence of microcystin-LR (MC-LR). The results showed that the bioaccumulation of MC-LR and Cu/Cd in C. demersum was significantly increased by the interaction between MC-LR and Cu/Cd. The combined toxicity assessment results suggested that the toxicities of Cu or Cd to C. demersum would be largely exacerbated by MC-LR, which could be the results of increased bioaccumulation of the pollutants. Cu, Cd and MC-LR, as well as their mixture, significantly decreased plant fresh weight and total chlorophyll content of C. demersum, especially at their high concentrations. The antioxidative system was activated to cope with the adverse effects of oxidative stress. Antioxidant enzyme activities were significantly stimulated by Cu, Cd and MC-LR, as well as their mixture. However, the decreased superoxide dismutase (SOD) and glutathione reductase (GR) activities were observed when exposed to relative high concentrations of Cu or Cd together with MC-LR of 5 µg L-1. MC-LR brought more stress to the antioxidative system, which is another possible explanation for the synergistic effect. Our findings highlight increased ecological risks of the co-contamination of heavy metals and harmful cyanobacteria.


Assuntos
Cádmio/toxicidade , Cobre/toxicidade , Microcistinas/toxicidade , Traqueófitas/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Organismos Aquáticos/efeitos dos fármacos , Traqueófitas/fisiologia
7.
Sci Total Environ ; 745: 141055, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-32736110

RESUMO

Plant seedlings are susceptible to copper (Cu) toxicity. As copper levels in soil continue to rise with the use of Cu-based agrochemicals, alleviation of Cu stress is of paramount importance. Traditional approaches to allay Cu stress are well documented but are typically found to be either costly or inefficient. Given their small size, ionic character, and high biocompatibility, specific polymeric nanoparticles (NPs) may have the potential for mitigating metal toxicity to crops. In this pioneering study, we investigated the effects of newly synthesized polysuccinimide NPs (PSI-NPs) on corn (Zea mays L.) seed germination and seedling growth under different levels of Cu stress. The results showed that PSI-NPs influenced seed germination in a dose-dependent manner with an optimal rate of 200 mg L-1. In addition, the positive effects of PSI-NPs on seed germination indexes were found to be positively correlated with enhanced seed imbibition (r = 0.82). The addition of PSI-NPs significantly mitigated Cu stress as indicated by improved growth of shoots and roots, and higher antioxidant enzyme activity observed with co-exposure to PSI-NPs as compared to Cu stress treatment only. Cu concentrations in seedling root and shoot significantly increased with increasing Cu treatment rate. Higher uptake of Cu by plant was observed in the Cu-PSI-NPs co-treatment than single Cu treatment. The alleviation effect of PSI-NPs could be explained by the enhanced antioxidant enzyme activities and storage of Cu as Cu-PSI complexes in plants with reduced phytotoxicity. These findings will open the opportunity of using PSI-NPs as a regulator to enhance seed germination and improve seedling growth under stress of heavy metals like Cu.


Assuntos
Germinação , Nanopartículas/toxicidade , Cobre/toxicidade , Raízes de Plantas , Plântula , Sementes
8.
Ecotoxicol Environ Saf ; 203: 110966, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32678755

RESUMO

We studied the effect of the chemical interaction of nutrients and the ethylenediamine tetraacetic acid (EDTA) on metals toxicity. Growth inhibition tests of Pseudokirchneriella subcapitata by nutrient metals copper (Cu) and zinc (Zn), and the non-nutrient metal lead (Pb), were performed. The high-enriched Bold's Basal medium (BBm) and two low-enriched standard media, recommended by the Organization for Economic Cooperation and Development (OECDm) and Environmental Protection Agency-algal assay procedure medium (AAPm), were used in this study. The metals toxicity was affected by the interaction of nutrients and EDTA. Cu+2 was more toxic in the OECDm (EC50 20.3 µg/L), while Pb+2 (EC50 23.1 µg/L) and Zn+2 (EC50 99.4 µg/L) in the AAPm. Non-toxic effect of these metals was observed in BBm, but the exclusion of EDTA shifted it into a toxic medium. Finally, we found that the toxicity of the studied nutrient metals is mainly influenced by EDTA, which reduced the concentration of ionized metals, while the toxicity of the non-nutrient metal is affected by EDTA and phosphates.


Assuntos
Monitoramento Biológico/métodos , Quelantes/farmacologia , Ácido Edético/farmacologia , Metais Pesados/toxicidade , Microalgas/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Bioensaio , Cobre/toxicidade , Relação Dose-Resposta a Droga , Interações Medicamentosas , Chumbo/toxicidade , Microalgas/crescimento & desenvolvimento , Modelos Teóricos , Zinco/toxicidade
9.
Ecotoxicol Environ Saf ; 203: 110979, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32678758

RESUMO

Recent EFSA (European Food Safety Authority) reports highlighted that the ecological risk assessment of pesticides needed to go further by taking more into account the impacts of chemicals on biodiversity under field conditions. We assessed the effects of two commercial formulations of fungicides separately and in mixture, i.e., Cuprafor Micro® (containing 500 g kg-1 copper oxychloride) at 4 (C1, corresponding to 3.1 mg kg-1 dry soil of copper) and 40 kg ha-1 (C10), and Swing® Gold (50 g L-1 epoxiconazole EPX and 133 g L-1 dimoxystrobin DMX) at one (D1, 5.81 10-2 and 1.55 10-1 mg kg-1 dry soil of EPX and DMX, respectively) and ten times (D10) the recommended field rate, on earthworms at 1, 6, 12, 18 and 24 months after the application following the international ISO standard no. 11268-3 to determine the effects on earthworms in field situations. The D10 treatment significantly reduced the species diversity (Shannon diversity index, 54% of the control), anecic abundance (29% of the control), and total biomass (49% of the control) over the first 18 months of experiment. The Shannon diversity index also decreased in the mixture treatment (both fungicides at the recommended dose) at 1 and 6 months after the first application (68% of the control at both sampling dates), and in C10 (78% of the control) at 18 months compared with the control. Lumbricus terrestris, Aporrectodea caliginosa, Aporrectodea giardi, Aporrectodea longa, and Allolobophora chlorotica were (in decreasing order) the most sensitive species to the tested fungicides. This study not only addressed field ecotoxicological effects of fungicides at the community level and ecological recovery, but it also pinpointed some methodological weaknesses (e.g., regarding fungicide concentrations in soil and statistics) of the guideline to determine the effects on earthworms in field situations.


Assuntos
Cobre/toxicidade , Monitoramento Ambiental/métodos , Compostos de Epóxi/toxicidade , Fungicidas Industriais/toxicidade , Oligoquetos/efeitos dos fármacos , Poluentes do Solo/toxicidade , Triazóis/toxicidade , Animais , Biodiversidade , Biomassa , Cobre/análise , Ecotoxicologia , Compostos de Epóxi/análise , Fungicidas Industriais/análise , Oligoquetos/crescimento & desenvolvimento , Medição de Risco , Solo/química , Poluentes do Solo/análise , Triazóis/análise
10.
Bull Environ Contam Toxicol ; 105(2): 255-260, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32632463

RESUMO

The present study investigated the biochemical toxicity and potential detoxification mechanisms in earthworms Eisenia fetida exposed to sulfamethazine (SMZ) (7.5, 15 and 30 mg kg-1) either alone or in combination with Copper (Cu) (100 mg kg-1) in soil. The results showed that increasing concentrations of SMZ in soil activated superoxide dismutase, catalase and glutathione peroxidase isozymes, suggesting reactive oxygen species (ROS) burst in earthworms. Treatment with SMZ and Cu separately or in combination caused protein oxidation and damage, elevating the synthesis of ubiquitin, the 20S proteasome, cytochrome P450 (CYP450), and heat shock protein 70 (HSP70). Such treatments also induced the activities of proteases, endoproteinase (EP) and glutathione S-transferases (GSTs). The results suggested that the ubiquitin-20S proteasome, proteases, EP and HSP70 were involved in degradation or remediation of oxidatively damaged proteins. Elevated levels of CYP450 and GSTs also participated in the detoxification of the earthworms.


Assuntos
Cobre/toxicidade , Oligoquetos/efeitos dos fármacos , Poluentes do Solo/toxicidade , Solo/química , Sulfametazina/toxicidade , Animais , Biodegradação Ambiental , Catalase/metabolismo , China , Cobre/metabolismo , Glutationa Peroxidase/metabolismo , Oligoquetos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Poluentes do Solo/metabolismo , Sulfametazina/metabolismo , Superóxido Dismutase/metabolismo
11.
Parasitol Res ; 119(9): 2783-2798, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32683559

RESUMO

Due to the increasing consumption of platinum (Pt), especially in automobile exhaust catalysts, environmental concentrations of Pt are of emerging concern worldwide. Limited information exists on environmental concentrations, particularly in Pt mining regions, while South Africa is the world's main supplier of Pt. Moreover, other metals are also released as by-products of Pt mining, which might also cause environmental concern. Certain fish parasite taxa have the ability to accumulate metals orders of magnitude higher than their hosts and can be used to reliably detect metals with naturally low abundance. Studies on Pt accumulation in parasite-host systems are limited. Therefore, the aims of the present study were (1) to determine the accumulation of a variety of metals (cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), platinum (Pt), and zinc (Zn)) in helminth fish parasites compared with their hosts from a reference site and an impoundment impacted by Pt mining activities; (2) to assess whether there is a difference between bioaccumulation of metals in infected and uninfected hosts, as well as between hosts with different infection intensities; and (3) to compare the biomarker responses (acetylcholine esterase activity (AChE), metallothionein content (MT), catalase activity (CAT), reduced glutathione content (GSH), malondialdehyde content (MDA), protein carbonyls induction (PC), superoxide dismutase activity (SOD), and cellular energy allocation (CEA)) between infected and uninfected hosts. The cestode Atractolytocestus huronensis accumulated significantly higher concentrations of Cr, Ni, and Pt than their host Cyprinus carpio, while the nematode Contracaecum sp. accumulated significantly higher concentrations of Pt and Zn than their host Clarias gariepinus. Infected fish showed lower metal concentrations compared to uninfected fish, while the parasites had no significant effects on their hosts' biomarker responses. The parasites demonstrated the bioavailability of metals derived from Pt mining activities and their ability to resist its toxic effects. Thus, these parasites are promising sensitive accumulation indicators for Cr, Ni, Pb, and Pt contaminations from Pt mining activities.


Assuntos
Bioacumulação/fisiologia , Cestoides/química , Metais Pesados/análise , Nematoides/química , Emissões de Veículos/análise , Poluentes Químicos da Água/análise , Acetilcolinesterase/metabolismo , Animais , Cádmio/análise , Cádmio/toxicidade , Carpas/parasitologia , Catalase/metabolismo , Peixes-Gato/parasitologia , Cobre/análise , Cobre/toxicidade , Ecossistema , Monitoramento Ambiental , Glutationa/análise , Malondialdeído/análise , Metalotioneína/análise , Metais Pesados/toxicidade , Parasitos , Platina/análise , Platina/toxicidade , África do Sul , Superóxido Dismutase/metabolismo , Emissões de Veículos/toxicidade , Poluentes Químicos da Água/toxicidade
12.
Sci Total Environ ; 745: 140926, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-32712499

RESUMO

Arsenic, copper, and zinc are common elements found in contaminated soils but little is known about their combined effects on plants when presented simultaneously. Here, we systematically investigated the phytotoxicity and uptake of binary and ternary mixtures of As, Cu, and Zn in a soil-plant system, using wheat (Triticum aestivum) as model species. The reference models of concentration addition (CA) and response addition (RA) coupled with different expressions of exposure (total concentrations in soil ([M]tot, mg/kg), free ion activities in soil solution ({M}, µM), and internal concentrations in plant roots ([M]int, µg/g)), were selected to assess the interaction mechanisms of binary mixtures of AsCu, AsZn, and CuZn. Metal(loid) interactions in soil were estimated in terms of solution-solid partitioning, root uptake, and root elongation effects. The partitioning of one metal(loid) between the soil solution and solid phase was most often inhibited by the presence of the other metal(loid). In terms of uptake, inhibitory effects and no effects were observed in the mixtures of As, Cu, and Zn, depending on the mixture combinations and the dose metrics used. In terms of toxicity, simple (antagonistic or synergistic) and more complex (dose ratio-dependent or dose level-dependent) interaction patterns of binary mixtures occurred, depending on the dose metrics selected and the reference models used. For ternary mixtures (As-Cu-Zn), nearly additive effects were observed irrespective of dose descriptors and reference models. The observed interactions in this study may help to understand and predict the joint toxicity of metal(loid)s mixtures in soil-plant system. Mixture interactions and bioavailability should be incorporated into the regulatory framework for accurate risk assessment of multimetal-contaminated sites.


Assuntos
Arsênico/toxicidade , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Cobre/toxicidade , Solo , Triticum/efeitos dos fármacos , Zinco/análise , Zinco/toxicidade
13.
Aquat Toxicol ; 226: 105556, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32652413

RESUMO

Ribosomal (r)DNA is a highly dynamic, conserved, multigene family whose sequence homogeneity is thought to be maintained by intra- and interchromosomal recombination, which are capable of changing rDNA copy number. It is generally not known how environmental stress such as sublethal exposure to environmentally relevant concentrations of metals impacts rDNA copy number. To determine how chronic metal exposure affects rDNA, we measured copy number of the 18S rRNA gene in 355 copper and nickel-exposed samples and 132 metal-free samples derived from 325 mutation accumulation (MA) lines of two genetically distinct Daphnia pulex lineages. The MA lines were sampled at four time points over 100+ generations of clonal propagation. The copy number of rDNA was also measured in 15 individuals sampled from a metal-free non-MA control population established from the same progenitor as one of the MA lineages. We found that mean rDNA copy number fluctuated across lines exposed to metals with a tendency to decrease over time. In contrast, mean rDNA copy number in the metal-free control lines and the non-MA population remained stable over time. It is generally accepted that extreme rDNA loss results in the loss of organism fitness. Thus, fluctuations in rDNA copy number, including losses, could affect the long-term viability of natural populations of Daphnia in metal-contaminated habitats.


Assuntos
Variações do Número de Cópias de DNA/efeitos dos fármacos , DNA Ribossômico/genética , Daphnia/efeitos dos fármacos , Metais Pesados/toxicidade , Acúmulo de Mutações , Poluentes Químicos da Água/toxicidade , Animais , Cobre/toxicidade , Daphnia/genética , Níquel/toxicidade , RNA Ribossômico 18S/genética , Reprodução/efeitos dos fármacos , Reprodução/genética
14.
Aquat Toxicol ; 226: 105561, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32688145

RESUMO

In the aquatic environment, metals are present as mixtures, therefore studies on mixture toxicity are crucial to thoroughly understand their toxic effects on aquatic organisms. Common carp (Cyprinus carpio) were used to assess the effects of short-term Cu(II) and Cd(II) mixtures, using a fixed concentration of one of the metals, representing 25 % of its individual 96h-LC50 (concentration lethal for 50 % of the population) combined with a variable concentration of the other metal corresponding to 10, 25 or 50 % of its 96h-LC50, and vice versa. Our results showed a fast Cu and Cd bioaccumulation, with the percentage of increase in the order gill > liver > carcass. An inhibitory effect of Cu on Cd uptake was observed; higher Cu concentrations at fixed Cd levels resulted in a decreased accumulation of Cd. The presence of the two metal ions resulted in losses of total Na, K and Ca. Fish tried to compensate for the Na loss through the induction of the genes coding for Na+/K+-ATPase and H+-ATPase. Additionally, a counterintuitive induction of the gene encoding the high affinity copper transporter (CTR1) occurred, while a downregulation was expected to prevent further metal ion uptake. An induction of defensive mechanisms, both metal ion binding protein and anti-oxidant defences, was observed. Despite the metal accumulation and electrolyte loss, the low mortality suggest that common carp is able to cope with these metal levels, at least during a one-week exposure.


Assuntos
Bioacumulação/efeitos dos fármacos , Cádmio/toxicidade , Carpas/metabolismo , Cobre/toxicidade , Homeostase/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Cádmio/metabolismo , Carpas/genética , Cobre/metabolismo , Transportador de Cobre 1/genética , Transportador de Cobre 1/metabolismo , Eletrólitos/metabolismo , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Transporte de Íons , Dose Letal Mediana , Potássio/metabolismo , Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Poluentes Químicos da Água/metabolismo
15.
Chemosphere ; 258: 127347, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32535433

RESUMO

The widespread use of copper oxide nanoparticles (CuONPs) has dramatically increased their concentrations in soils and severely affected the health of soil organisms. The gut microbiota critically contributes to the metabolism and immune system of its host and is sensitive to environmental pollution. The toxic effect of CuONPs on the gut microbiota, especially in soil fauna, still needs further research. In the present study, a comprehensive toxicological test was performed to reveal the effects of CuONPs and their metal counterpart on the gut microbiota of soil collembolans using Illumina high throughput sequencing. Furthermore, the concomitant changes in the collembolans gut-associated antibiotic resistance genes (ARGs) and metabolism were investigated using high-throughput quantitative PCR and carbon and nitrogen stable isotope compositions. Both CuONPs and ionic copper (Cu) exposure disturbed the collembolan gut microbial community structure while only CuONPs reduced the gut microbial diversity. A total of 66 ARGs were detected in the collembolan guts, and CuONPs exposure induced a reduction in both diversity and abundance of ARGs. Additionally, CuONPs and ionic Cu exposure altered the C and N stable isotope compositions of the collembolans, indicating a change in their metabolism. Moreover, structural equation modeling indicated that 85.5% of the carbon stable isotope variations and 73.3% of the nitrogen stable isotope variations were explained by changes in Cu bioaccumulation and the gut microbiota. The results of the present study extend our knowledge regarding the comprehensive toxicity of metal oxide NPs on soil fauna.


Assuntos
Artrópodes/microbiologia , Cobre/toxicidade , Microbioma Gastrointestinal/efeitos dos fármacos , Poluentes do Solo/toxicidade , Animais , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/genética , Nanopartículas Metálicas , Microbiota/efeitos dos fármacos , Nanopartículas , Solo/química
16.
Artigo em Inglês | MEDLINE | ID: mdl-32588237

RESUMO

Chromated copper arsenate (CCA) mixtures were used in the past for wood preservation, leading to large scale soil contamination. This study aimed at contributing to the risk assessment of CCA-contaminated soils by assessing the toxicity of binary mixtures of copper, chromium and arsenic to the earthworm Eisenia andrei in OECD artificial soil. Mixture effects were related to reference models of Concentration Addition (CA) and Independent Action (IA) using the MIXTOX model, with effects being related to total and available (H2O and 0.01 M CaCl2 extractable) concentrations in the soil. Since only in mixtures with arsenic dose-related mortality occurred (LC50 92.5 mg/kg dry soil), it was not possible to analyze the mixture effects on earthworm survival with the MIXTOX model. EC50s for effects of Cu, Cr and As on earthworm reproduction, based on total soil concentrations, were 154, 449 and 9.1 mg/kg dry soil, respectively. Effects of mixtures were mainly antagonistic when related to the CA model but additive related to the IA model. This was the case when mixture effects were based on total and H2O-extractable concentrations; when based on CaCl2-extractable concentrations effects mainly were additive related to the CA model except for the Cr-As mixture which acted antagonistically. These results suggest that the CCA components do interact leading to a reduced toxicity when present in a mixture.


Assuntos
Arsênico/toxicidade , Cromo/toxicidade , Cobre/toxicidade , Oligoquetos/efeitos dos fármacos , Poluentes do Solo/toxicidade , Animais , Arseniatos/toxicidade , Testes de Toxicidade
17.
Chemosphere ; 259: 127436, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32599387

RESUMO

Copper (Cu) is an essential metal for human, animals and plants, although it is also potentially toxic above supra-optimal levels. In plants, Cu is an essential cofactor of numerous metalloproteins and is involved in several biochemical and physiological processes. However, excess of Cu induces oxidative stress inside plants via enhanced production of reactive oxygen species (ROS). Owing to its dual nature (essential and a potential toxicity), this metal involves a complex network of uptake, sequestration and transport, essentiality, toxicity and detoxification inside the plants. Therefore, it is vital to monitor the biogeo-physiochemical behavior of Cu in soil-plant-human systems keeping in view its possible essential and toxic roles. This review critically highlights the latest understanding of (i) Cu adsorption/desorption in soil (ii) accumulation in plants, (iii) phytotoxicity, (iv) tolerance mechanisms inside plants and (v) health risk assessment. The Cu-mediated oxidative stress and resulting up-regulation of several enzymatic and non-enzymatic antioxidants have been deliberated at molecular and cellular levels. Moreover, the role of various transporter proteins in Cu uptake and its proper transportation to target metalloproteins is critically discussed. The review also delineates Cu build-up in plant food and accompanying health disorders. Finally, this review proposes some future perspectives regarding Cu biochemistry inside plants. The review, to a large extent, presents a complete picture of the biogeo-physiochemical behavior of Cu in soil-plant-human systems supported with up-to-date 10 tables and 5 figures. It can be of great interest for post-graduate level students, scientists, industrialists, policymakers and regulatory authorities.


Assuntos
Cobre/metabolismo , Poluentes do Solo/metabolismo , Antioxidantes/metabolismo , Cobre/toxicidade , Humanos , Estresse Oxidativo/fisiologia , Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Medição de Risco , Solo/química , Poluentes do Solo/química , Poluentes do Solo/toxicidade
18.
Mar Environ Res ; 158: 105005, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32501269

RESUMO

In order to investigate the combined toxicities of copper nanoparticles (nano-Cu) with microplastic on microalgae Skeletonema costatum, growth inhibition tests were carried out. The toxic effects of copper nanoparticles and microplastic on the microalgae under singleness and coexistence conditions were investigated. Both copper nanoparticles and microplastic inhibited the growth of S. costatum. The growth inhibition ratio (IR) increased with the increasing of particle concentrations and incubation time. The toxicity of copper nanoparticles was reduced with the addition of microplastic. The concentrations of Cu2+ in the medium with or without addition of microplastic were determined. It was found that adsorption of Cu2+ on microplastic and aggregation between copper nanoparticles and microplastic are the main reasons for attenuation of toxicity of nano-Cu with adding microplastic. The adhesion and aggregate interactions between microalgae and nanomaterial were also approved by the observations through scanning electron microscopy.


Assuntos
Cobre , Diatomáceas , Microalgas , Nanopartículas , Cobre/toxicidade , Microalgas/efeitos dos fármacos , Microalgas/crescimento & desenvolvimento , Microplásticos , Nanopartículas/toxicidade , Plásticos
19.
Toxicol Appl Pharmacol ; 401: 115090, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32512069

RESUMO

Copper dyshomeostasis is involved in the pathogenesis of Alzheimer's disease (AD). Microglia play a major role in the proteolytic clearance of oligomeric ß-amyloid (Aßo). Here, we investigated whether Cu(II) affects microglial Aßo clearance and whether this effect involves autophagy-lysosomal pathway. Microtubule associated protein 1 light chain 3 (LC3)-II and p62 protein levels and autophagic flux in Cu(II)-treated microglia were detected. Aßo clearance was detected by enzyme-linked immunosorbent assay (ELISA) and immunofluorescence. In vivo, Cu(II) and Aßo were injected into mouse hippocampus to evaluate Aß clearance. The results showed that Cu(II) inhibited phagocytic uptake and intracellular degradation of Aßo in microglial cultures. Additionally, Cu(II) elevated LC3-II and p62 protein levels and impaired autophagic flux. It also inhibited transcription factor EB (TFEB) expression and lysosomal biogenesis. Moreover, Cu(II) activated mammalian target of rapamycin kinase (mTOR), an upstream signaling of TFEB. The mTOR inhibitor PP242 ameliorated Cu(II)-impaired TFEB expression, lysosomal biogenesis, autophagic flux, and Aßo clearance in microglia. In vivo, Cu(II) inhibited microglial Aßo clearance in mouse hippocampus, an effect accompanied with activation of mTOR and impairment of TFEB expression and lysosomal biogenesis. Collectively, our results suggest that Cu(II) reduces microglial Aßo clearance through disrupting lysosomal biogenesis and autophagic flux. This effect could involve modulation of mTOR-TFEB axis and was prevented by pharmacological antagonism of mTOR. This study reveals a novel mechanism for Cu(II) involvement in AD. Our results implicate that rescue of Cu(II)-impaired autophagy-mediated lysosomal degradation may provide a new strategy to benefit multiple neurodegenerative disorders.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Cobre/toxicidade , Lisossomos/metabolismo , Microglia/metabolismo , Fragmentos de Peptídeos/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Peptídeos beta-Amiloides/antagonistas & inibidores , Animais , Animais Recém-Nascidos , Autofagia/efeitos dos fármacos , Autofagia/fisiologia , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/antagonistas & inibidores , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Relação Dose-Resposta a Droga , Lisossomos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Fragmentos de Peptídeos/antagonistas & inibidores , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Serina-Treonina Quinases TOR/antagonistas & inibidores
20.
Bull Environ Contam Toxicol ; 105(1): 62-66, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32556375

RESUMO

The various uses of copper or copper compounds in industrial, biocidal or pesticidal products lead to inputs of the metal into aquatic environments. To assess effects of copper ions on non-target organisms, the freshwater snail Theodoxus fluviatilis was used as test organism for a three-week laboratory experiment. Snails were exposed to four copper concentrations ranging from 4 to 39 µg Cu2+/L, and besides mortality, several sublethal parameters were evaluated. Concerning survival, an aqueous copper concentration of 6 µg/L was determined as NOEC, and 16 (± 0.1) µg/L as LC50. Negative sublethal effects on reproduction, activity and pathological modifications in the snails were detected in the treatment with an aqueous copper concentration of 15 µg/L. Our results using T. fluviatilis as a mere grazer exclusively feeding on biofilms contribute to findings that field relevant copper concentrations have a significant effect on non-target organisms in aquatic environments.


Assuntos
Cobre/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Água Doce , Íons , Reprodução/efeitos dos fármacos , Caramujos/efeitos dos fármacos
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