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1.
Ecotoxicol Environ Saf ; 201: 110850, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32531571

RESUMO

Despite of significant progress in remediation of Cr(VI) or Hg(II) pollution by microorganisms, study on the reduction of both Cr(VI) and Hg(II) by the same microbial strain was not reported so far, which is actually important for bioremediation of contaminated sites with multiple heavy metals. In this study, Pseudomonas umsongensis CY-1 was newly isolated from chromium-contaminated soil and showed remediation potentials for both Cr(VI) and Hg(II) pollution. The highest Cr(VI) (93.9%) and Hg(II) (82.8%) reduction rates were obtained at the initial concentration of 5 mg/L. Comparison between removal by resting cells and heat-treated resting cells demonstrated that P. umsongensis CY-1 removed Cr(VI) and Hg(II) from Tris-HCl buffer (pH 7.0) mainly through reduction instead of adsorption. By comparing the Cr(VI) and Hg(II) reduction rates of different cellular fractions, it was found that Cr(VI) and Hg(II) reductions mainly happened in the cytoplasm of P. umsongensis CY-1, which were further demonstrated by Transmission electron microscopy (TEM) analysis. Furthermore, analysis of X-ray photoelectron spectroscopy demonstrated that the reduction products of Cr(VI) and Hg(II) were mainly in the form of Cr(III) and Hg (0), respectively. The findings in this study will provide a guide for further insights in the bioremediation of contaminated sites with multiple heavy metals.


Assuntos
Cromo/análise , Compostos de Mercúrio/análise , Pseudomonas/metabolismo , Poluentes do Solo/análise , Adsorção , Biodegradação Ambiental , Cromo/metabolismo , Compostos de Mercúrio/metabolismo , Modelos Teóricos , Oxirredução , Filogenia , Pseudomonas/isolamento & purificação , Poluentes do Solo/metabolismo
2.
Chemosphere ; 251: 126295, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32143074

RESUMO

Rasasindura (RS) is an Ayurvedic medicine, which contains ∼99% α-HgS. It is used as a rejuvenating agent and commonly used to treat diseases such as syphilis, insomnia, high fever, and nervous disorders. Cinnabar ore (α-HgS) is a well-known mineral, which is readily available. Despite it, Ayurvedic practitioners adopted an involved and tedious procedure for the preparation of RS. In this study, three samples, one was Ayurvedic (RS), the second one was the commercial (HGS), and the third one was cinnabar ore (CN), were physiochemically examined. Zebrafish model was employed for toxicity study with an oral dose of 100 mg/kg/day for the three samples for 10 days. We found that RS conferred novel physicochemical properties, which were not seen in HGS and CN. Significantly, the average crystallite size of RS was lowest (26 nm) as compared to HGS (31 nm) and CN (34 nm), and the rate of increase of crystallite size with temperature was lowest in RS. RS did not show any significant behavioral toxicity in zebrafish, which was seen with the HGS-and CN-treated zebrafish. HGS-and CN-treated zebrafish showed a significantly high (∗∗∗p < 0.001) decrease (77 ± 7.6% and 51 ± 6.5%, respectively) of glutathione (GSH) levels in the brain, however, for RS-treated zebrafish, the change of GSH was insignificant (26 ± 2.5%, p > 0.05). Interestingly, HGS significantly altered the γ-aminobutyric acid (GABA) in brain tissue. Therefore, among all three samples, RS exhibited the lowest toxicity, which can be credited to the distinct toxicokinetics by these samples.


Assuntos
Compostos de Mercúrio/química , Poluentes Químicos da Água/química , Animais , Encéfalo , Glutationa , Medicina Ayurvédica , Compostos de Mercúrio/toxicidade , Toxicocinética , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
4.
J Ethnopharmacol ; 247: 112299, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31606537

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Hua-Feng-Dan (HFD) is a traditional Chinese medicine used for neurological disorders. HFD contains cinnabar (HgS) and realgar (As4S4). The ethnopharmacological basis of cinnabar and realgar in HFD is not known. AIM OF THE STUDY: To address the role of cinnabar and realgar in HFD-produced neuroprotection against neurodegenerative diseases and disturbance of gut microbiota. MATERIALS AND METHODS: Lipopolysaccharide (LPS) plus rotenone (ROT)-elicited rat dopaminergic (DA) neuronal damage loss was performed as a Parkinson's disease animal model. Rats were given a single injection of LPS. Four months later, rats were challenged with the threshold dose of ROT. The clinical dose of HFD was administered via feed, starting from ROT administration for 46 days. Behavioral dysfunction was detected by rotarod and Y-maze tests. DA neuron loss and microglial activation were assessed via immunohistochemical staining and western bolt analysis. The colon content was collected to extract bacterial DNA followed by real-time PCR analysis with 16S rRNA primers. RESULTS: LPS plus ROT induced neurotoxicity, as evidenced by DA neuron loss in substantia nigra, impaired behavioral functions and increased microglial activation. HFD-original (containing 10% cinnabar and 10% realgar) rescued loss of DA neurons, improved behavioral dysfunction and attenuated microglial activation. Compared with HFD-original, HFD-reduced (3% cinnabar and 3% realgar) was also effective, but to be a less extent, while HFD-removed (without cinnabar and realgar) was ineffective. In analysis of gut microbiome, the increased Verrucomicrobiaceae and Lactobacteriaceae, and the decreased Enterobacteeriaceae by LPS plus ROT were ameliorated by HFD-original, and to be the less extent by HFD-reduced. CONCLUSION: Cinnabar and realgar are active ingredients in HFD to exert beneficial effects in a neurodegenerative model and gut microbiota.


Assuntos
Arsenicais/farmacologia , Medicamentos de Ervas Chinesas/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Compostos de Mercúrio/farmacologia , Fármacos Neuroprotetores/farmacologia , Síndromes Neurotóxicas/tratamento farmacológico , Sulfetos/farmacologia , Animais , Arsenicais/química , Arsenicais/uso terapêutico , DNA Bacteriano/isolamento & purificação , Modelos Animais de Doenças , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/patologia , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/uso terapêutico , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Etnofarmacologia , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/imunologia , Humanos , Mediadores da Inflamação/metabolismo , Lactobacillaceae/efeitos dos fármacos , Lactobacillaceae/genética , Lactobacillaceae/isolamento & purificação , Lipopolissacarídeos/toxicidade , Masculino , Compostos de Mercúrio/química , Compostos de Mercúrio/uso terapêutico , Microglia/efeitos dos fármacos , Microglia/imunologia , Microglia/patologia , Degeneração Neural , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/uso terapêutico , Síndromes Neurotóxicas/etiologia , Síndromes Neurotóxicas/imunologia , Síndromes Neurotóxicas/patologia , RNA Ribossômico 16S/genética , Ratos , Rotenona/toxicidade , Sulfetos/química , Sulfetos/uso terapêutico , Verrucomicrobia/efeitos dos fármacos , Verrucomicrobia/genética , Verrucomicrobia/isolamento & purificação
5.
Ecotoxicol Environ Saf ; 184: 109623, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31518823

RESUMO

This study provides information on mercury (Hg) localization, speciation and ligand environment in edible mushrooms: Boletus edulis, B. aereus and Scutiger pes-caprae collected at non-polluted and Hg polluted sites, by LA-ICP-MS, SR-µ-XRF and Hg L3-edge XANES and EXAFS. Mushrooms (especially young ones) collected at Hg polluted sites can contain more than 100 µg Hg g-1 of dry mass. Imaging of the element distribution shows that Hg accumulates mainly in the spore-forming part (hymenium) of the cap. Removal of hymenium before consumption can eliminate more than 50% of accumulated Hg. Mercury is mainly coordinated to di-thiols (43-82%), followed by di-selenols (13-35%) and tetra-thiols (12-20%). Mercury bioavailability, as determined by feeding the mushrooms to Spanish slugs (known metal bioindicators owing to accumulation of metals in their digestive gland), ranged from 4% (S. pes-caprae) to 30% (B. aereus), and decreased with increasing selenium (Se) levels in the mushrooms. Elevated Hg levels in mushrooms fed to the slugs induced toxic effects, but these effects were counteracted with increasing Se concentrations in the mushrooms, pointing to a protective role of Se against Hg toxicity through HgSe complexation. Nevertheless, consumption of the studied mushroom species from Hg polluted sites should be avoided.


Assuntos
Agaricales/química , Contaminação de Alimentos/análise , Compostos de Mercúrio/análise , Poluentes do Solo/análise , Agaricales/metabolismo , Animais , Disponibilidade Biológica , Monitoramento Ambiental , Carpóforos/química , Carpóforos/metabolismo , Gastrópodes/metabolismo , Compostos de Mercúrio/metabolismo , Compostos de Mercúrio/toxicidade , Selênio/análise , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidade
6.
Environ Pollut ; 255(Pt 1): 113128, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31521990

RESUMO

Atmospheric deposition, either dry or wet, has been identified as an important pathway of mercury (Hg) input to terrestrial and aquatic systems. Although East Asia is the major atmospheric Hg emission source region, very few studies have been conducted to quantify atmospheric Hg deposition in its downwind region. In this study, 8-year (2009-2016) atmospheric Hg dry deposition was reported at the Lulin Atmospheric Background Station (LABS), a high mountain forest site in central Taiwan. Dry deposition of speciated Hg was estimated using a bi-directional air-surface flux exchange model for gaseous elemental mercury (GEM) and dry deposition models for gaseous oxidized mercury (GOM) and particulate-bound mercury (PBM), making use of the monitored speciated atmospheric Hg concentrations. Annual total Hg dry deposition ranged from 51.9 to 84.9 µg m-2 yr-1, with a multi-year average of 66.1 µg m-2 yr-1. Among the three forms of atmospheric Hg, GEM was the main contributor to the total dry deposition, contributing about 77.8% to the total, due to the high density of forest canopy as well as the much higher concentration of GEM than GOM and PBM at LABS. Mercury dry deposition is higher in winter and spring than in summer and fall, partly due to the elevated Hg concentrations associated with air masses from East and Southeast Asia where with high atmospheric Hg emissions. The mean annual dry/wet deposition ratio of 2.8 at LABS indicated that Hg deposition to forest landscape was governed by dry rather than wet deposition.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Compostos de Mercúrio/análise , Mercúrio/análise , Óxidos/análise , Grupo com Ancestrais do Continente Asiático , Extremo Oriente , Florestas , Gases/análise , Humanos , Estações do Ano , Taiwan
7.
Environ Pollut ; 255(Pt 2): 113271, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31550655

RESUMO

Most mercury (Hg) deposition in the environment results from anthropogenic inputs, Chlor-Alkali Plants (CAPs) particularly had a significant Hg impact on the environment at a regional scale. Exposure to mercury compounds resulting in various toxic effects for living organisms. The aim of this study was to investigate the capacity of granular sulphur (S) soil amendment and cultivation of Dactylis glomerata to decrease gaseous mercury emission to the atmosphere and mercury mobility in soils affected by CAP activity in the past. The effect of this approach on D. glomerata physiological status was also assessed (Hg concentration in biomass, chlorophyll a fluorescence, pigment contents and oxidative stress). Stabilization of mercury in soil and reduction of root and shoot concentration did not influence biomass production. Despite similar yields, photosynthetic efficiency was higher for plants grown in sulphur amended soil compared to unamended soil, particularly observed in phenomenological energy fluxes. Relative chlorophyll content was 30% lower for amended soil plants, however based on chlorophyll fluorescence data those were in high portion ineffective. Oxidative stress products and catalase activity did not differ significantly between experimental treatments. Sulphur amendment was a key factor for reduction of Hg mobility in soil (reduced by about 30%) while plant cover was significant for the reduction of Hg atmospheric emission (emissions were 2-times higher in sulphur amended soil without plant cover). Due to the very high concentration of Hg in soil (798.2 ±â€¯7.3 mg kg-1), growth inhibition was consistent regardless of treatment, demonstrated in the overload Reactive Oxygen Species scavenging mechanism and similar biomass yields. This leads to the conclusion that Hg may have greater impact on Calvin-Benson cycle associated enzymes than on the light-dependent photosynthesis phase. Despite these limitations this approach may still decrease environmental risks by reducing Hg emission to the atmosphere and reducing groundwater contamination.


Assuntos
Biodegradação Ambiental , Dactylis/fisiologia , Mercúrio/análise , Poluentes do Solo/análise , Animais , Clorofila/metabolismo , Clorofila A , Compostos de Mercúrio , Fotossíntese , Solo , Enxofre
8.
Anal Chim Acta ; 1083: 150-156, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31493805

RESUMO

Most of the on-site approaches for inferring of the post-mortem interval are still based on observative data from the direct body inspection, whereas, objective and quantitative analyses, such as potassium in the vitreous humor, are require laboratory instrumentation and skilled personnel. The present paper presents a simple and low cost analytical method suitable for use at the crime scene for inferring the time since death. The method uses a microfluidic paper-based device (µPAD) for the determination of ammonium in the vitreous humor (VH) based on the selective interaction between the ammonium and the Nessler's reagent. The color change was measured in terms of "RGB distance" by using a simple and free smartphone application. The optimized device showed a limit of detection of 0.4 mmol L-1, with between days precision less than 9.3% expressed as relative standard deviation, and accuracy between days from 94.5% to 104.5%. The selectivity of the Nessler's reaction was tested towards the main vitreous humor compounds, and no significant interferences were found. This paper-based analytical device was successfully used for the determination of ammonium ion in VH samples from forensic autopsies. The results obtained with the proposed method, although for a limited number of cases (n = 25), showed a close correlation with the data obtained with an instrumental analysis based on capillary electrophoresis. Moreover, in order to make the evaluation of results as simple as possible, a direct correlation between the color intensity, expressed as RGB distance, and the post-mortem interval was studied and a significant correlation was found (R2 > 0.78). In conclusion, the present preliminary study showes that the proposed device could be an additional tool to the traditional methods for a more accurate, although still presumptive, estimation of the time of death directly at the crime scene.


Assuntos
Compostos de Amônio/análise , Medicina Legal/métodos , Papel , Mudanças Depois da Morte , Corpo Vítreo/química , Adulto , Idoso , Colorimetria/instrumentação , Colorimetria/métodos , Medicina Legal/instrumentação , Humanos , Iodetos/química , Limite de Detecção , Compostos de Mercúrio/química , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Pessoa de Meia-Idade , Estudo de Prova de Conceito , Reprodutibilidade dos Testes , Fatores de Tempo , Adulto Jovem
9.
Bioengineered ; 10(1): 353-364, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31431119

RESUMO

Cinnabar is an attractive mineral with many different uses. It is reported that cinnabar is one of the traditional Chinese's medicines extensively use. The main objective of this critical review is to identify the current overview, concept and chemistry of cinnabar, which includes the process developments, challenges, and diverse options for pharmacology research. It is used as a medicine through probable toxicity, especially when taking overdoes. This review is the first to describe the toxicological effects of cinnabar and its associated compounds. Nuclear magnetic resonance (NMR) dependent metabolomics could be useful for examination of the pharmaceutical consequence. The analysis indicated that the accurate preparation methods, appropriate doses, disease status, ages with drug combinations are significant factors for impacting the cinnabar toxicity. Toxicologically, synthetic mercury sulfide or cinnabar should be notable for mercuric chloride, mercury vapor and methyl mercury for future protection and need several prominent advancements in cinnabar research.


Assuntos
Amnésia/tratamento farmacológico , Hipnóticos e Sedativos/uso terapêutico , Compostos de Mercúrio/uso terapêutico , Nootrópicos/uso terapêutico , Agitação Psicomotora/tratamento farmacológico , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Lesão Renal Aguda/induzido quimicamente , Lesão Renal Aguda/patologia , Amnésia/fisiopatologia , Animais , Cálculos da Dosagem de Medicamento , História Antiga , Humanos , Hipnóticos e Sedativos/química , Hipnóticos e Sedativos/isolamento & purificação , Hipnóticos e Sedativos/toxicidade , Medicina Ayurvédica/história , Medicina Ayurvédica/métodos , Medicina Tradicional Chinesa/história , Medicina Tradicional Chinesa/métodos , Compostos de Mercúrio/química , Compostos de Mercúrio/isolamento & purificação , Compostos de Mercúrio/toxicidade , Camundongos , Nootrópicos/química , Nootrópicos/isolamento & purificação , Nootrópicos/toxicidade , Agitação Psicomotora/fisiopatologia , Distúrbios do Início e da Manutenção do Sono/fisiopatologia , Testes de Toxicidade
10.
J Microbiol ; 57(10): 918-926, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31463789

RESUMO

Trypanosoma cruzi is an obligate intracellular parasite transmitted to vertebrate hosts by blood-sucking insects. Molecules present in parasites and mammalian cells allow the recognition and parasite internalization. Metallic ions play an essential role in the establishment and maintenance of host-parasite interaction. However, little is known about how parasites handle with essential and nonessential metal quotas. This study aimed to investigate the influence of metal ions on the biological processes of T. cruzi infected cells. Infected cells were incubated with ZnCl2, CdCl2, and HgCl2 for 12 h and labeled with different specific dyes to investigate the cellular events related to intracellular parasite death and elimination. Infected host cells and parasite's mitochondria underwent functional and structural disorders, in addition to parasite's DNA condensation and pH decrease on host cells, which led to parasite death. Further investigations suggested that lysosomes were involved in pH decrease and the double membrane of the endoplasmic reticulum formed vacuoles surrounding damaged parasites, which indicate the occurrence of autophagy for parasite elimination. In conclusion, low concentrations of nonessential and essential metals cause a series of damage to Trypanosoma cruzi organelles, leading to its loss of viability, death, and elimination, with no removal of the host cells.


Assuntos
Autofagia/efeitos dos fármacos , Cloreto de Cádmio/farmacologia , Cloretos/farmacologia , Compostos de Mercúrio/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Compostos de Zinco/farmacologia , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Trypanosoma cruzi/citologia , Trypanosoma cruzi/metabolismo , Vacúolos/efeitos dos fármacos , Vacúolos/metabolismo
11.
Int J Paleopathol ; 26: 84-92, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31349131

RESUMO

We carried out a differential diagnosis of a large frontoparietal lesion on a human skull from a Late Bronze Age archaeological site located on the Central Plain of China, dating to between 771 and 476 BC. The head of this individual was covered in cinnabar, a mercury-based pigment that later was used for medicinal purposes in China. The lesion was well-circumscribed and involved the outer and inner tables of the skull, slight diploë thickening, and coarsening of bone trabeculae with expansion of intertrabecular spaces. We show that the observed changes are most consistent with cavernous hemangioma of the skull, a benign vascular malformation that preferentially affects older adults. Hemangiomas are often neglected in the paleopathological literature because of their benign nature - they tend to be asymptomatic and do not affect quality of life to a significant degree. Nevertheless, they produce characteristic lesions that can be confused with several other conditions with unrelated etiologies, including congenital hemoglabinopathies, traumas, malignant or benign neoplasms, and Paget's disease. We outline the diagnostic criteria that distinguish cavernous hemangioma from other conditions affecting the skull.


Assuntos
Hemangioma Cavernoso do Sistema Nervoso Central/história , Meningioma/história , Paleopatologia , Crânio/patologia , China , Fósseis/patologia , Hemangioma Cavernoso do Sistema Nervoso Central/diagnóstico , Hemangioma Cavernoso do Sistema Nervoso Central/patologia , História Antiga , Humanos , Masculino , Meningioma/diagnóstico , Meningioma/patologia , Compostos de Mercúrio/história , Pessoa de Meia-Idade , Múmias/patologia
12.
Macromol Rapid Commun ; 40(18): e1900228, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31298758

RESUMO

Online chemically sensitive detectors for size exclusion chromatography (SEC) through coupled setups based on infrared (IR) (or NMR) spectrometers present new possibilities through unprecedented levels of polymer detail with respect to molecular weight and chemical composition. Herein, a new external cavity quantum cascade laser (EC-QCL) mid-IR spectrometer as a chemically sensitive online detector for SEC is custom-designed, built, and tested. This unique spectrometer features multiple broadly tunable EC-QCL sources, which can be operated in continuous wave and pulsed mode, accompanied with balanced liquid nitrogen cooled mercury cadmium telluride (MCT) detectors and a new custom-built transmission flow cell. Automated data analysis is done with a self-written MATLAB code. The limit of detection (LOD) is measured online, coupled with SEC chromatography, where on average, one carbonyl functionality in 530 000 g mol-1 at chromatographic conditions for SEC could be detected. It is possible to detect 0.46 µg (LOD) PMMA, which is approximately a factor of 30 lower than that reported for SEC-Fourier transform infrared.


Assuntos
Cromatografia em Gel/métodos , Lasers Semicondutores , Polímeros/química , Compostos de Cádmio/química , Compostos de Mercúrio/química , Peso Molecular , Polímeros/análise , Espectrofotometria Infravermelho/métodos
13.
Environ Sci Pollut Res Int ; 26(24): 24831-24839, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31240653

RESUMO

Adsorption is a typical method for air pollutant removal from flue gas. A CuS-modified active coke (CuS/AC) sorbent was developed to improve the elemental mercury removal efficiency from municipal solid waste incineration (MSWI) flue gas. The influences of the loading amount of CuS, reaction temperature, and flue gas components including O2, SO2, H2O, and HCl on Hg0 removal efficiency were investigated, respectively. The results showed that the mercury adsorption capacity of CuS/AC(20%) sorbent was about 7.17 mg/g with 50% breakthrough threshold, which is much higher than that of virgin active coke. The analysis of XPS indicated that HgS was the main species of mercury on spent CuS/AC, which implied that adsorption and oxidation were both included in Hg0 removal. S22- played a vital role in the oxidation of physically adsorbed Hg0. Meanwhile, the common components of MSWI flue gas exhibited no significant inhibition effect on Hg0 removal by CuS/AC sorbent. CuS/AC sorbent is a promising sorbent for the mercury removal from MSWI flue gas.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Coque , Cobre/química , Incineração , Mercúrio/isolamento & purificação , Adsorção , Poluentes Atmosféricos/química , Gases/química , Mercúrio/química , Compostos de Mercúrio/análise , Compostos de Mercúrio/isolamento & purificação , Oxirredução , Resíduos Sólidos , Enxofre/química , Dióxido de Enxofre/química , Temperatura
14.
Environ Sci Pollut Res Int ; 26(19): 19588-19597, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31077054

RESUMO

In this study, an innovative analytical methodology capable of selectively identifying and quantifying mercury contamination by the association of solid-phase extraction using ion-imprinted polymers as a sorbent phase and differential pulse anodic stripping voltammetry is proposed. To this end, the ion-imprinted polymers were synthesized and characterized by infrared spectroscopy and atomic force microscopy. The sorption capacities and the selectivity of the ion-imprinted polymers were compared to the ones related to the non-imprinted ones. Next, the experimental parameters of this solid-phase extraction method (IIP-SPE) were evaluated univariately. The selectivity of this polymeric matrix against other cations (Cd II, Pb II, and Cu II) was also evaluated. Limits of detection (LOD) and quantification (LOQ) obtained for the here proposed methodology were 0.322 µg L-1 and 1.08 µg L-1, respectively. Also, the precision of 4.0% was achieved. The method was finally applied to three water samples from different sources: for the Piratininga and Itaipu Lagoon waters, Hg II concentrations were below the LOQ and for Vargem River waters a concentration equal to 1.35 ± 0.07 mg L-1 was determined. These results were confirmed by recovery tests, resulting in a recovery of 96.2 ± 4.0%, and by comparison with flame atomic absorption spectrometry, resulting in statistical conformity between the two methods at 95% confidence level.


Assuntos
Monitoramento Ambiental/métodos , Compostos de Mercúrio/análise , Impressão Molecular , Compostos Organomercúricos/análise , Polímeros/síntese química , Poluentes Químicos da Água/análise , Brasil , Eletrodos , Água Doce/química , Limite de Detecção , Polímeros/química , Extração em Fase Sólida
15.
Environ Pollut ; 249: 647-654, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30933762

RESUMO

Rice grain is known to accumulate methylmercury (MeHg) and has been confirmed to be the major pathway of MeHg exposure to residents in mercury (Hg) mining areas in China. Selenium (Se) supplementation has been proven to be effective in mitigating the toxicity of Hg. To understand how Se supplementation influences soil Hg speciation, a wide range of Se (0-500 mg/kg) was applied to Hg polluted paddy soils in this study, which decreased MeHg concentration in soil from 2.95 ±â€¯0.36 to 0.69 ±â€¯0.16 µg/kg (or 77%). After Se addition, humic acid state Hg (F4) was transformed into strong-complexed state Hg (F5), indicating that Hg bound up to the non-sulfur functional groups of humic acid (non-RSH) was released and reabsorbed by strong binding Se functional group (F5). As a result, inorganic Hg (IHg) was reduced by >48%, 18%, and 80% in root, stem, and grain, respectively, however, the reduction was not apparent in leaf. Substantial reductions were also found for MeHg in grain and root, but not in stem and leaf. Soil is suggested to be the main source of both MeHg and IHg in rice grain. Such a finding may provide an idea for improving Hg-polluted paddies through controlling soil IHg and MeHg. Further research on the molecular structure of the strong-complexed Hg in F5 should be conducted to elucidate the mechanism of Hg-Se antagonism.


Assuntos
Compostos de Mercúrio/análise , Mercúrio/análise , Compostos de Metilmercúrio/análise , Oryza/efeitos dos fármacos , Selênio/química , Poluentes do Solo/análise , Transporte Biológico , China , Grão Comestível/química , Substâncias Húmicas/análise , Compostos de Mercúrio/metabolismo , Compostos de Metilmercúrio/metabolismo , Mineração , Oryza/metabolismo , Estruturas Vegetais/metabolismo , Selênio/farmacologia , Solo/química
16.
Electrophoresis ; 40(23-24): 3050-3056, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30963594

RESUMO

The original manuscript of Casanova's Memoirs is stored at the Bibliothèque Nationale de France in Paris. We have gained access to it and explored the surfaces of chapters one and two (via the ethylene vinyl acetate [EVA] film technology, i.e., of diskettes of ethylene vinyl acetate with embedded strong cation and anion exchangers and C8 resins) in search of potential diseases of the author, especially of the gonorrhea bacterium, since Casanova reported that he had several bouts of this pathology along his adventurous life. Although the bacterium was not found, we have detected high levels of HgS as red spots along the lines of the manuscript, suggesting that Casanova was using this chemical as a cure for his venereal disease. Additionally, among the several bacteria identified on the surface via mass spectrometry, we could detect traces of Streptococcus uberis, a typical animal infection, found also in humans, together with a few strains of Lactobacilli, probably present in his saliva. The EVA film technology appears to open new horizons for investigating the world Cultural Heritage.


Assuntos
Livros/história , Tipagem Molecular/métodos , Redação/história , Proteínas de Bactérias/análise , Proteínas de Bactérias/química , Proteínas de Bactérias/classificação , França , História do Século XVIII , Humanos , Lactobacillus/química , Espectrometria de Massas/métodos , Compostos de Mercúrio/análise , Compostos de Mercúrio/química , Polivinil , Streptococcus/química
17.
mBio ; 10(2)2019 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-30940703

RESUMO

Mercury (Hg) is a widely distributed, toxic heavy metal with no known cellular role. Mercury toxicity has been linked to the production of reactive oxygen species (ROS), but Hg does not directly perform redox chemistry with oxygen. How exposure to the ionic form, Hg(II), generates ROS is unknown. Exposure of Thermus thermophilus to Hg(II) triggered ROS accumulation and increased transcription and activity of superoxide dismutase (Sod) and pseudocatalase (Pcat); however, Hg(II) inactivated Sod and Pcat. Strains lacking Sod or Pcat had increased oxidized bacillithiol (BSH) levels and were more sensitive to Hg(II) than the wild type. The ΔbshA Δsod and ΔbshA Δpcat double mutant strains were as sensitive to Hg(II) as the ΔbshA strain that lacks bacillithiol, suggesting that the increased sensitivity to Hg(II) in the Δsod and Δpcat mutant strains is due to a decrease of reduced BSH. Treatment of T. thermophilus with Hg(II) decreased aconitase activity and increased the intracellular concentration of free Fe, and these phenotypes were exacerbated in Δsod and Δpcat mutant strains. Treatment with Hg(II) also increased DNA damage. We conclude that sequestration of the redox buffering thiol BSH by Hg(II), in conjunction with direct inactivation of ROS-scavenging enzymes, impairs the ability of T. thermophilus to effectively metabolize ROS generated as a normal consequence of growth in aerobic environments.IMPORTANCE Thermus thermophilus is a deep-branching thermophilic aerobe. It is a member of the Deinococcus-Thermus phylum that, together with the Aquificae, constitute the earliest branching aerobic bacterial lineages; therefore, this organism serves as a model for early diverged bacteria (R. K. Hartmann, J. Wolters, B. Kröger, S. Schultze, et al., Syst Appl Microbiol 11:243-249, 1989, https://doi.org/10.1016/S0723-2020(89)80020-7) whose natural heated habitat may contain mercury of geological origins (G. G. Geesey, T. Barkay, and S. King, Sci Total Environ 569-570:321-331, 2016, https://doi.org/10.1016/j.scitotenv.2016.06.080). T. thermophilus likely arose shortly after the oxidation of the biosphere 2.4 billion years ago. Studying T. thermophilus physiology provides clues about the origin and evolution of mechanisms for mercury and oxidative stress responses, the latter being critical for the survival and function of all extant aerobes.


Assuntos
Catalase/metabolismo , Cisteína/análogos & derivados , Tolerância a Medicamentos , Glucosamina/análogos & derivados , Compostos de Mercúrio/toxicidade , Superóxido Dismutase/metabolismo , Thermus thermophilus/efeitos dos fármacos , Thermus thermophilus/enzimologia , Catalase/genética , Cisteína/metabolismo , Deleção de Genes , Glucosamina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/genética , Thermus thermophilus/genética , Thermus thermophilus/metabolismo
18.
Environ Monit Assess ; 191(5): 263, 2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-30953219

RESUMO

The aims of this study were to investigate the occurrence and distribution of total mercury (Hg) and other trace elements of environmental concern, such as arsenic (As), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn) and vanadium (V), in soils from the abandoned Merník cinnabar mine in eastern Slovakia. For this purpose, thirty soil samples from two depth intervals within the mine area (n = 60 soil samples) and additional sixteen soil samples from adjacent areas (n = 25 soil samples) were collected. Total Hg was measured by atomic absorption spectrometry, while As and other metals were analyzed using inductively coupled plasma atomic emission spectrometry. High mercury concentrations (> 100 mg/kg with a maximum of 951 mg/kg) were observed only in surface soils close to mine waste heaps and adits. Otherwise, Hg concentrations in the majority of surface soils were lower (0.14-19.7 mg/kg), however, higher than Hg in soils collected from sites outside the mine area (0.19-6.92 mg/kg) and even considerably higher than Hg in soils at sites not influenced by the Merník mine. Elevated Cr and Ni concentrations in soils regardless of their sampling sites (mean of 276 mg/kg and median of 132 mg/kg for Cr and 168 mg/kg and 81 mg/kg for Ni, respectively) were attributed to the lithology of the area; the soils are underlain by the sediments of the Central Carpathian Palaeogene, containing a detritus of ultrabasic rocks. As our geochemical data are compositional in nature, they were further treated by compositional data analysis (CoDA). Robust principal component analysis (RPCA) applied on centred (clr) log-ratio-transformed data and correlation analysis of compositional parts based on symmetric balances distinguished very well different sources of origin for the chemical elements. The following three element associations were identified: Hg association with the main source in mining/roasting, Cr-Ni association derived from bedrock and As-Cu-Mn-Pb-Zn-V association (natural background and minor sulphides/sulfosalts in mineralized rocks). The values of geoaccumulation index and enrichment factor suggested that concentrations of Hg in the soils were influenced by human industrial activities.


Assuntos
Cromo/análise , Mercúrio/análise , Níquel/análise , Poluentes do Solo/análise , Solo/química , Oligoelementos/análise , Monitoramento Ambiental , Atividades Humanas , Humanos , Compostos de Mercúrio , Mineração , Eslováquia
19.
Sci Total Environ ; 665: 1125-1134, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30893744

RESUMO

The soils and food webs associated with mid to high elevation, forested, headwater streams in northeastern North America are potential hotspots for mercury (Hg) methylation and bioaccumulation, but are not well studied. Our goals were to quantify total Hg (THg) and methyl Hg (MeHg) concentrations in soils and terrestrial food webs associated with headwater streams of northern hardwood forests to identify predictors of small-scale spatial variation in Hg bioaccumulation. We sampled soil characteristics that promote Hg methylation including pH, sulfur and calcium content, and organic matter. To assess spatial variation, we sampled at high (~700 m asl) and mid elevations (~500 m asl), both adjacent to (<1 m) and away from (>75 m) three replicate headwater streams in each of two watersheds of the White Mountains region, New Hampshire, USA. Soils of these forested watersheds differed significantly in pH and the content of calcium, sulfur, organic matter and THg. Conditions for methylation were more favorable in the upland forest sites compared to streamside sites. Significant bioaccumulation of THg occurred in all measured components of the food web, including insects, spiders, salamanders, and birds. Trophic position, as determined by δ15N, was the best predictor of both THg and MeHg bioaccumulation across the sampled taxa and was also a better predictor than spatial location. However, the degree of bioaccumulation at which MeHg significantly affects animal behavior, reproduction or survival is unknown for most taxa in terrestrial habitats, particularly for invertebrates. These findings show that Hg methylation and bioaccumulation is not limited to areas traditionally classified as wetlands or to areas with exceptionally high THg inputs, but that it is a widespread and important phenomenon in the moist deciduous forests of eastern North America.


Assuntos
Cadeia Alimentar , Invertebrados/fisiologia , Compostos de Mercúrio/metabolismo , Mercúrio/metabolismo , Vertebrados/fisiologia , Poluentes Químicos da Água/metabolismo , Animais , Organismos Aquáticos/fisiologia , Florestas , Metilação , New Hampshire , Rios
20.
Ecotoxicology ; 28(4): 412-421, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30874993

RESUMO

The development of marine water quality criteria (WQC) in China has been insufficient because data on the toxicity of pollutants for marine organisms based on the species sensitivity distribution (SSD) method are lacking. The Chinese aquatic environmental quality standards, including those for seawater, were derived from the developed countries. Therefore, establishing Chinese marine WQC is crucial for identifying the sensitivity of marine species in China and will improve their protection from threats. Mercury (Hg) is one of the primary pollutants commonly exceeding Chinese seawater quality standards. Several countries have developed their marine WQC for inorganic Hg in the past decades, but no study has been conducted in China. In this study, 45 acute toxicity and 14 chronic toxicity data of inorganic Hg on the marine species which inhabit in China were obtained mainly from the ECOTOX database, the CNKI, and the Google Scholar. The acute and chronic hazardous concentrations for 5% of the species (HC5) were calculated based on the best-fit distribution model Sweibull. The criteria for maximum and continuous concentrations of 1.30 and 0.66 µg/L, respectively, for inorganic Hg to protect marine organisms in China were derived by halving the HC5 values. The criteria were comparable to those of the United States, Australia, and the European Union countries, indicating the general applicability of WQCs developed based on the classical SSD method using different species groups. This study may provide valuable information for assessing marine ecological risk in China.


Assuntos
Compostos de Mercúrio/análise , Mercúrio/análise , Água do Mar/química , Poluentes Químicos da Água/análise , Qualidade da Água/normas , Organismos Aquáticos , China , Guias como Assunto
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