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1.
Ecotoxicol Environ Saf ; 208: 111744, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396070

RESUMO

Arsenic (As) a non-essential element is of particular concern with respect to harmful effects on plant metabolism. While extensive studies have been conducted on the physiological responses of plants to increase As concentrations, however, molecular differences elucidating species-specific changes remain largely unknown. In the present experiment, two oilseed Brassica napus (B. napus) cultivars, ZS758 and ZD622, were treated by elevated As concentration. Their responses to the As stress have been investigated through pulse amplitude modulated fluorometer and isobaric tags based proteomic (iTRAQ) analysis. The chlorophyll fluorescence attributes showed that As stress significantly decrease the photochemical efficiency of photosystem II (PSII) and photosystem I (PSI) as well as the comparatively closed stomata observed under scanning electron microscopy (SEM). In this study, 65 proteins displayed increased abundance and 52 down-regulated were found in the control vs As comparison in cultivar ZS758, while 44 up and 67 down-regulated proteins were found in the control vs As comparison in ZD622. Metabolic pathways, followed by ribosome and biosynthesis of secondary metabolites were the dominant functional annotation categories among the differentially expressed protein (DEPs). Many genes involved in primary metabolism, stress and defense were found to be As-responsive DEPs and/or DEPs between these two cultivars. Based on these results, a schematic description of key processes involved in As tolerance in ZS758 and ZD622 is proposed, which suggests that higher tolerance in ZS758 depends on a multilevel coordination of efficient defense and energy metabolism. Real-time quantitative PCR supported the expression patterns of several genes encoding a protein similar to their corresponding DEPs. In addition, these findings could shed light in unraveling the molecular mechanisms of B. napus exposed to As stress and provide or improve essential understandings in the development of advanced B. napus cultivars against As resistance.


Assuntos
Arsênico/toxicidade , Brassica napus/efeitos dos fármacos , Proteoma/metabolismo , Arsênico/metabolismo , Metabolismo Energético , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Proteômica/métodos
2.
Ecotoxicol Environ Saf ; 208: 111721, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396052

RESUMO

The City of Yellowknife is a known hotspot of arsenic contamination and there is a growing body of evidence suggesting that local wildlife in the vicinity of the abandoned Giant Mine site may be at risk of decreased bone mineralization and various bone disorders. The purpose of this study was to preliminarily measure bone mineral density (BMD) changes and investigate the incidence, pattern, and severity of bone lesions in wild muskrats and red squirrels breeding in three (3) catchment areas at different distances from the Giant Mine Site in Yellowknife, Northwest Territories (Canada): ~2 km (location 1), ~18 km (location 2), and ~40-100 km (location 3). Full femoral bones of 15 muskrats and 15 red squirrels were collected from the three sampling locations (5 from each location) and subjected to radiographic analysis and densitometric measurements. The patterns and severities of bone lesions, including changes in bone mineral density, were evaluated and compared between groups. As levels were significantly higher in the bones of muskrats caught from location 1 and 2, relative to location 3. Further, As and Cd levels were significantly higher in the bones of squirrels caught from locations 1 and 2 relative to squirrels caught from location 3. The preliminary results from bones revealed that radiographic abnormalities such as bone rarefaction, osteopenia, and thinning of the femoral shafts with significant ossific cystic lesions and bowing were the most common skeletal pathologies found in bones of red squirrels from the three locations. Radiographic appearances of massive sclerosis and dysplasia, including severe osteocondensation and osteopathia striata-like abnormalities, were found in the bones of muskrats from all the sampling locations. Densitometric evaluation showed no significant differences between the three locations in the bone parameters measured. However, there was a statistically significant correlation between As content in the bones of muskrats and percent fat content in the femur samples, which suggests that accumulation of As could have been a causal factor for a change in percent fat in femurs of muskrats.


Assuntos
Intoxicação por Arsênico/veterinária , Arsênico/efeitos adversos , Densidade Óssea/efeitos dos fármacos , Doenças Ósseas/veterinária , Poluentes Ambientais/envenenamento , Animais , Animais Selvagens , Arsênico/metabolismo , Intoxicação por Arsênico/diagnóstico por imagem , Intoxicação por Arsênico/patologia , Arvicolinae , Doenças Ósseas/induzido quimicamente , Doenças Ósseas/diagnóstico por imagem , Doenças Ósseas/patologia , Densitometria , Poluentes Ambientais/análise , Gorduras/metabolismo , Feminino , Fêmur/diagnóstico por imagem , Fêmur/efeitos dos fármacos , Fêmur/metabolismo , Fêmur/patologia , Territórios do Noroeste/epidemiologia , Sciuridae
3.
Ecotoxicol Environ Saf ; 208: 111752, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396077

RESUMO

Arsenic is a toxic heavy metal vastly dispersed all over the earth crust. It manifests several major adverse health issues to millions of arsenic exposed populations. Arsenic is associated with different types of cancer, cardiovascular disorders, diabetes, hypertension and many other diseases. On the contrary, arsenic (arsenic trioxide, As2O3) is used as a chemotherapeutic agent in the treatment of acute promyelocytic leukemia. Balance between arsenic induced cellular proliferations and apoptosis finally decide the outcome of its transformation rate. Arsenic propagates signals via cellular and nuclear pathways depending upon the chemical nature, and metabolic-fates of the arsenical compounds. Arsenic toxicity is propagated via ROS induced stress to DNA-repair mechanism and mitochondrial stability in the cell. ROS induced alteration in p53 regulation and some mitogen/ oncogenic functions determine the transformation outcome influencing cyclin-cdk complexes. Growth factor regulator proteins such as c-Jun, c-fos and c-myc are influenced by chronic arsenic exposure. In this review we have delineated arsenic induced ROS regulations of epidermal growth factor receptor (EGFR), NF-ĸß, MAP kinase, matrix-metalloproteinases (MMPs). The role of these signaling molecules has been discussed in relation to cellular apoptosis, cellular proliferation and neoplastic transformation. The arsenic stimulated pathways which help in proliferation and neoplastic transformation ultimately resulted in cancer manifestation whereas apoptotic pathways inhibited carcinogenesis. Therapeutic strategies against arsenic should be designed taking into account all these factors.


Assuntos
Arsênico/fisiologia , Proliferação de Células/fisiologia , Plásticos/metabolismo , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Arsênico/metabolismo , Trióxido de Arsênio/metabolismo , Trióxido de Arsênio/farmacologia , Arsenicais/metabolismo , Proliferação de Células/efeitos dos fármacos , Humanos , Mitocôndrias/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neoplasias , Óxidos/toxicidade , Transdução de Sinais/efeitos dos fármacos
4.
Ecotoxicol Environ Saf ; 208: 111693, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396024

RESUMO

Arsenic is a natural chemical element that is strongly associated with bladder cancer. Understanding the underlying mechanisms behind the association between arsenic and bladder cancer as well as identifying effective preventive interventions will help reduce the incidence and mortality of this disease. The epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) properties play key roles in cancer development and progression. Here, we reported that chronic exposure to arsenic resulted in EMT and increased levels of the CSC marker CD44 in human uroepithelial cells. Furthermore, IL-8 promoted a mesenchymal phenotype and upregulated CD44 by activating the ERK, AKT and STAT3 signaling. Phosphorylation of the human epidermal growth factor receptor 2 (HER2) was key for arsenic-induced IL-8 overexpression and depended on the simultaneous activation of the MAPK, JNK, PI3K/AKT and GSK3ß signaling pathways. We also found that genistein inhibited arsenic-induced HER2 phosphorylation and downregulated its downstream signaling pathways, thereby inhibiting progression of EMT, and reducing CD44 expression levels. These results demonstrate that the HER2/IL-8 axis is related to the acquisition of an EMT phenotype and CSCs in arsenic-treated cells. The inhibitory effects of genistein on EMT and CSCs provide a new perspective for the intervention and potential chemotherapy against arsenic-induced bladder cancer.


Assuntos
Arsênico/toxicidade , Células Epiteliais/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Interleucina-8/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Receptor ErbB-2/genética , Bexiga Urinária/metabolismo , Arsênico/metabolismo , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Movimento Celular/imunologia , Sobrevivência Celular/efeitos dos fármacos , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Transição Epitelial-Mesenquimal/imunologia , Humanos , Receptores de Hialuronatos/genética , Células-Tronco Neoplásicas/imunologia , Células-Tronco Neoplásicas/metabolismo , Fenótipo , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Bexiga Urinária/citologia
5.
Ecotoxicol Environ Saf ; 209: 111793, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33360287

RESUMO

Arsenic (As) toxicity can be a hazardous threat to sustainable agriculture and human health. Piriformospora indica (P. indica), as a beneficial endophytic fungus, is involved in the plant tolerance to stressful conditions. Here, the biochemical and molecular responses of rice plants to As (50 µM) phytotoxicity and P. indica inoculation as well as the role of P. indica in improving rice adaptation to As stress were evaluated. The results showed that As stress reduced chlorophylls content, chlorophyll fluorescence yield (Fv/Fm), electron transport rate (ETR) and growth. However, P. indica restored chlorophyll content and growth. P. indica decreased the contents of methylglyoxal and malondialdehyde by improving the activity of enzymes involved in the glyoxalase pathway and modulating the redox state of the ascorbic acid-glutathione cycle, and consequently, increased the plant tolerance to As toxicity. P. indica, by downregulating Lsi2 expression (involved in As translocation to the shoot) and upregulating PCS1 and PCS2 expression (involved in As sequestration in vacuoles), immobilized As in the roots and reduced damage to photosynthetic organs. P. indica increased iron (Fe) accumulation in the shoot under As toxicity by upregulating the expression of IRO2, YSL2 and FRDL1 genes. The results of the present study augmented our knowledge in using P. indica symbiosis in improving the tolerance of rice plants against As toxicity for sustainable agriculture.


Assuntos
Adaptação Fisiológica/fisiologia , Arsênico/toxicidade , Basidiomycota/fisiologia , Oryza/fisiologia , Poluentes do Solo/toxicidade , Arsênico/metabolismo , Basidiomycota/metabolismo , Clorofila/metabolismo , Humanos , Ferro/metabolismo , Malondialdeído/metabolismo , Oryza/metabolismo , Oryza/microbiologia , Fotossíntese , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Poluentes do Solo/metabolismo , Simbiose
6.
Ecotoxicol Environ Saf ; 207: 111379, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33017691

RESUMO

The use of irrigation water containing arsenic (As) had led to large areas of As-contaminated farmland, and as a result, plants and food have become severely poisoned. Humic acid (HA) can be complexed with metals, which in turn affects the metals' behavior. Herein, we explored the accumulation of arsenate in lettuce treated with different concentrations of arsenate and studied the effects of HA on the accumulation and toxicity of arsenate. The addition of HA did not cause significant changes in the arsenate content in lettuce but had a significant effect on the activity of antioxidant enzymes, which improved the antioxidant capability of the lettuce plants. Furthermore, HA promoted the accumulation of nutrients, such as magnesium (Mg), calcium (Ca), molybdenum (Mo) and manganese (Mn), in the leaves. Arsenate disrupted metabolic pathways, such as amino acid metabolism, carbohydrate metabolism, and aminoacyl-tRNA biosynthesis. The addition of HA increased the contents of amino acids and sugars, thereby improving lettuce growth. The present study explored the effects of HA on As accumulation and related physiological changes (antioxidant enzyme activities, absorption of nutrients and metabolic mechanisms) and provided insights into the regulation of As contamination by HA, which is relatively inexpensive.


Assuntos
Arseniatos/toxicidade , Substâncias Húmicas/análise , Antioxidantes/metabolismo , Arseniatos/metabolismo , Arsênico/metabolismo , Alface/efeitos dos fármacos , Manganês/metabolismo , Minerais/metabolismo , Folhas de Planta/metabolismo
7.
Ecotoxicol Environ Saf ; 207: 111559, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33254413

RESUMO

The current study was performed to investigate the protective effects of dietary Haematococcus pluvialis (H. pluvialis) on the oxidative stress induced by arsenic in rainbow trout (Oncorhynchus mykiss). The fish (20.70 ± 0.09 g) were fed with H. pluvialis at the levels of 0.28, 0.56, and 1.12 g 100 g-1 diet for 60 days. Then, each group was divided into two subgroups. In one of the subgroups, fish were exposed to arsenic challenge at a level of 9.1 mg/L. The other subset was used as the negative control. After the 96 h of toxicity test, protein and lipid oxidative levels, antioxidant-relevant gene expression as well as several chemical factors, including pH and peroxide value and moisture content, were evaluated in the fillet samples. Results showed that feeding with H. pluvialis decreased the levels of pH, peroxide value, as well as protein and lipid oxidation levels in treatment groups. Besides, the expression of antioxidant genes was significantly increased in the groups administrated with H. pluvialis. Based on the results of this study, feeding H. pluvialis attenuated the oxidative stress induced by arsenic in rainbow trout fillet through improving the antioxidant defense system.


Assuntos
Arsênico/toxicidade , Clorofíceas/fisiologia , Oncorhynchus mykiss/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Arsênico/metabolismo , Clorofíceas/metabolismo , Dieta , Oncorhynchus mykiss/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos
8.
Chemosphere ; 262: 128384, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182105

RESUMO

Arsenic (As) polluted food chain has become a serious issue for the growth and development of humans, animals and plants. Nitric oxide (NO) or silicon (Si) may mitigate As toxicity. However, the combined application of NO and Si in mitigating As uptake and phytotoxicity in Brassica juncea is unknown. Hence, the collegial effect of sodium nitroprusside (SNP), a NO donor and Si application on B. juncea growth, gas exchange parameters, antioxidant system and As uptake was examined in a greenhouse experiment. Arsenic toxicity injured cell membrane as signposted by the elevated level of malondialdehyde (MDA) and hydrogen peroxide (H2O2), thus decreasing the growth of stressed plants. Moreover, As stress negatively affected gas exchange parameters and antioxidative system of plants. However, NO or/and Si alleviated As induced oxidative stress through increasing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), along with thiol and proline synthesis. Furthermore, plants treated with co-application of NO and Si showed improved growth, gas attributes and decreased As uptake under As regimes. The current study highlights that NO and Si synergistically interact to mitigate detrimental effects of As stress through reducing As uptake. Our findings recommend combined NO and Si application in As spiked soils for improvement of plant growth and stress alleviation.


Assuntos
Arsênico/metabolismo , Mostardeira/fisiologia , Óxido Nítrico/química , Silício/química , Poluentes do Solo/metabolismo , Antioxidantes/metabolismo , Arsênico/toxicidade , Ascorbato Peroxidases/metabolismo , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Mostardeira/metabolismo , Doadores de Óxido Nítrico/metabolismo , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Poluentes do Solo/toxicidade , Superóxido Dismutase/metabolismo
9.
Ecotoxicol Environ Saf ; 207: 111273, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32916524

RESUMO

Toxic pollutant (TP) detection in situ using analytical instruments or whole-cell biosensors is inconvenient. Designing and developing genetically coded biosensors in vitro for real-world TP detection is a promising alternative. However, because the bioactivity and stability of some key biomolecules are weakened in vitro, the response and regulation of reporter protein become difficult. Here, we established a genetically encoded biosensor in vitro with an arsenical resistance operon repressor (ArsR) and GFP reporter gene. Given that the wildtype ArsR did not respond to arsenic and activate GFP expression in vitro, we found, after screening, an evolved ArsR mutant ep3 could respond to arsenic and exhibited an approximately 3.4-fold fluorescence increase. Arsenic induced expression of both wildtype ArsR and ep3 mutant in vitro, however, only ep3 mutant regulated the expression of reporter gene. Furthermore, the effects of cell extracts, temperature, pH, incubation, and equilibrium time were investigated, and the equilibration of reaction mixtures for 30 min at 37 °C was found to be essential for in vitro arsenic detection prior to treatment with arsenic. Based on our data, we established a standard procedure for arsenic detection in vitro. Our results will facilitate the practical application of genetically encoded biosensors in TP monitoring.


Assuntos
Arsênico/análise , Técnicas Biossensoriais/métodos , Poluentes Ambientais/análise , Arsênico/metabolismo , Arsenicais/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Genes Reporter/efeitos dos fármacos , Óperon/efeitos dos fármacos
10.
Ecotoxicol Environ Saf ; 206: 111336, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32977084

RESUMO

Widespread arsenic (As) contamination is a severe environmental and public health concern. Isatis cappadocica, an arsenic hyperaccumulator, holds great potential to clean up As-contaminated soil and groundwater. Iron oxide is one of the most common metal oxides in the natural environment and its nanoparticulate form has been previously utilized for the removal of heavy metals/metalloids from wastewater. However, there is a paucity of information on the impact of iron oxide nanoparticles on the growth and physiological properties of I. cappadocica and its effectiveness on As removal. Current study reports for the first time the impact of superparamagnetic iron oxide nanoparticles and glutathione (GSH) modified superparamagnetic iron oxide nanoparticles (nFe3O4 and nFe3O4@GSH) on the physiological characteristic of I. cappadocica and its accumulation of As under hydroponic condition. nFe3O4@GSH alleviated the harmful impact of As and significantly increased the shoot biomass of I. cappadocica by enhancing the plant defense mechanisms. The application of GSH, nFe3O4 and nFe3O4@GSH all lowered the As concentration in plant shoots as a protective mechanism. However, the substantial shoot biomass increase due to nFe3O4@GSH resulted in a 56% higher As accumulation in plant shoots than in plants exposed to As alone, indicating the strong effectiveness of nFe3O4@GSH as a novel enhancer of the As phytoremediation by I. cappadocica. Our data further showed that the beneficial effect of nFe3O4@GSH on As phytoremediation is due to the enhancement of activities of several enzymatic and nonenzymatic antioxidants.


Assuntos
Arsênico/metabolismo , Glutationa/metabolismo , Isatis/fisiologia , Poluentes do Solo/metabolismo , Antioxidantes , Arsênico/análise , Biodegradação Ambiental , Compostos Férricos , Hidroponia , Nanopartículas de Magnetita , Metais Pesados , Plantas
11.
Chemosphere ; 261: 127712, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32736245

RESUMO

The export of e-waste from industrialized to developing countries has led to the formation of a large-scale informal e-waste recycling sector in Accra, Ghana. During recycling processes, workers are exposed to several hazardous substances, such as heavy metals. As a common component of e-waste, inorganic arsenic can be released during e-waste recycling processes. The aim of this study was to assess the exposure to inorganic arsenic species in e-waste workers compared to a control group. N = 84 e-waste workers and n = 94 control subjects were included in this analysis. Inorganic arsenic species were determined in urine samples using HPLC-ICP-MS. E-waste workers showed higher median concentrations of As(III), As(V), MMA, DMA and the sum of inorganic arsenic in comparison to the control group. More than 80% of the e-waste workers exceeded the acceptable concentration (14 µg/L), which was significantly higher in comparison to the control group (70%). The tolerable concentration (40 µg/L) was exceeded in 17.2% of the participants, meaning a statistically relevant risk of developing cancer due to arsenic exposure throughout their (working) life. In conclusion, the exposure to inorganic arsenic is not only a problem of informal e-waste recycling, but a major public health concern that needs further investigation.


Assuntos
Arsênico/metabolismo , Resíduo Eletrônico/análise , Exposição Ocupacional/estatística & dados numéricos , Arsênico/análise , Arsenicais , Estudos Transversais , Feminino , Gana , Humanos , Masculino , Metais Pesados/análise , Pessoa de Meia-Idade , Reciclagem
12.
Appl Environ Microbiol ; 86(21)2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-32859593

RESUMO

Arsenate is a notorious toxicant that is known to disrupt multiple biochemical pathways. Many microorganisms have developed mechanisms to detoxify arsenate using the ArsC-type arsenate reductase, and some even use arsenate as a terminal electron acceptor for respiration involving arsenate respiratory reductase (Arr). ArsC-type reductases have been studied extensively, but the phylogenetically unrelated Arr system is less investigated and has not been characterized from Archaea Here, we heterologously expressed the genes encoding Arr from the crenarchaeon Pyrobaculum aerophilum in the euryarchaeon Pyrococcus furiosus, both of which grow optimally near 100°C. Recombinant P. furiosus was grown on molybdenum (Mo)- or tungsten (W)-containing medium, and two types of recombinant Arr enzymes were purified, one containing Mo (Arr-Mo) and one containing W (Arr-W). Purified Arr-Mo had a 140-fold higher specific activity in arsenate [As(V)] reduction than Arr-W, and Arr-Mo also reduced arsenite [As(III)]. The P. furiosus strain expressing Arr-Mo (the Arr strain) was able to use arsenate as a terminal electron acceptor during growth on peptides. In addition, the Arr strain had increased tolerance compared to that of the parent strain to arsenate and also, surprisingly, to arsenite. Compared to the parent, the Arr strain accumulated intracellularly almost an order of magnitude more arsenic when cells were grown in the presence of arsenite. X-ray absorption spectroscopy (XAS) results suggest that the Arr strain of P. furiosus improves its tolerance to arsenite by increasing production of less-toxic arsenate and nontoxic methylated arsenicals compared to that by the parent.IMPORTANCE Arsenate respiratory reductases (Arr) are much less characterized than the detoxifying arsenate reductase system. The heterologous expression and characterization of an Arr from Pyrobaculum aerophilum in Pyrococcus furiosus provides new insights into the function of this enzyme. From in vivo studies, production of Arr not only enabled P. furiosus to use arsenate [As(V)] as a terminal electron acceptor, it also provided the organism with a higher resistance to arsenate and also, surprisingly, to arsenite [As(III)]. In contrast to the tungsten-containing oxidoreductase enzymes natively produced by P. furiosus, recombinant P. aerophilum Arr was much more active with molybdenum than with tungsten. It is also, to our knowledge, the only characterized Arr to be active with both molybdenum and tungsten in the active site.


Assuntos
Proteínas Arqueais/genética , Arseniato Redutases/genética , Regulação da Expressão Gênica em Archaea , Pyrococcus furiosus/genética , Thermoproteaceae/genética , Proteínas Arqueais/metabolismo , Arseniato Redutases/metabolismo , Arsênico/metabolismo , Microrganismos Geneticamente Modificados/enzimologia , Microrganismos Geneticamente Modificados/genética , Microrganismos Geneticamente Modificados/metabolismo , Pyrococcus furiosus/enzimologia , Pyrococcus furiosus/metabolismo
13.
Rev Environ Health ; 35(3): 277-280, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-32651989

RESUMO

Objectives Exposure to inorganic arsenic (iAs) is a world-wide health concern. We reported that Japanese children and pregnant women are exposed to moderate levels of iAs through food. Reducing iAs contamination from foods of high iAs is an important issue unique in Japan. Integrated iAs is methylated to less toxic organic forms, and S-adenosyl-L-methyonine (SAM), a common methyl-donor of DNA and histones, is utilized in this process. Chronic consumption of SAM by iAs metabolism due to exposure to iAs might alter the epigenetic modification of genome. The SAM biosynthesis pathway is dependent on folate cycle, and it is possible that ingestion of sufficient folic acid (FA) is protective to iAs induced toxicity. Methods In the course of our cross-sectional body burden analyses of Pb and iAs in Japanese children and pregnant women, termed "PbAs study", FA concentration in serum of 104 pregnant women was measured. Results Mean (±SEM) of serum FA concentration was 15.8 ± 1.3 (ng/mL). There are significant number of people showing very high FA (>30 ng/ mL), and large fraction of them were taking supplements daily. Conclusions These results suggested that level of FA ingestion of Japanese pregnant women is high for supporting normal fetal development.


Assuntos
Ácido Fólico/sangue , Adulto , Arsênico/metabolismo , Feminino , Humanos , Japão , Chumbo/metabolismo , Gravidez , Adulto Jovem
14.
Chemosphere ; 259: 127410, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32615455

RESUMO

Arsenic (As) can be present naturally in groundwater from peanut fields, constituting a serious problem, as roots can accumulate and mobilize the metalloid to their edible parts. Understanding the redox changes in the legume exposed to As may help to detect potential risks to human health and recognize tolerance mechanisms. Thirty-days old peanut plants inoculated with Bradyrhizobium sp. strains (SEMIA6144 or C-145) were exposed to a realistic arsenate concentration, in order to unravel the redox response and characterize the oxidative stress indexes. Thus, root anatomy, reactive oxygen species detection by fluorescence microscopy and, ROS histochemical staining along with the NADPH oxidase activity were analyzed. Besides, photosynthetic pigments and damage to lipids and proteins were determined as oxidative stress indicators. Results showed that at 3 µM AsV, the cross-section areas of peanut roots were augmented; NADPH oxidase activity was significantly increased and O2˙¯and H2O2 accumulated in leaves and roots. Likewise, an increase in the lipid peroxidation and protein carbonyls was also observed throughout the plant regardless the inoculated strain, while chlorophylls and carotenes were increased only in those inoculated with Bradyrhizobium sp. C-145. Interestingly, the oxidative burst, mainly induced by the NADPH oxidase activity, and the consequent oxidative stress was strain-dependent and organ-differential. Additionally, As modifies the root anatomy, acting as a possibly first defense mechanism against the metalloid entry. All these findings allowed us to conclude that the redox response of peanut is conditioned by the rhizobial strain, which contributes to the importance of effectively formulating bioinoculants for this crop.


Assuntos
Arachis/microbiologia , Arsênico/toxicidade , Bradyrhizobium/fisiologia , Estresse Oxidativo/fisiologia , Arachis/efeitos dos fármacos , Arachis/metabolismo , Arachis/fisiologia , Arseniatos , Arsênico/metabolismo , Bradyrhizobium/efeitos dos fármacos , Bradyrhizobium/metabolismo , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos , Oxirredução , Raízes de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Simbiose/efeitos dos fármacos
15.
Sci Rep ; 10(1): 10946, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32616801

RESUMO

Mononuclear molybdoenzymes of the dimethyl sulfoxide reductase (DMSOR) family catalyze a number of reactions essential to the carbon, nitrogen, sulfur, arsenic, and selenium biogeochemical cycles. These enzymes are also ancient, with many lineages likely predating the divergence of the last universal common ancestor into the Bacteria and Archaea domains. We have constructed rooted phylogenies for over 1,550 representatives of the DMSOR family using maximum likelihood methods to investigate the evolution of the arsenic biogeochemical cycle. The phylogenetic analysis provides compelling evidence that formylmethanofuran dehydrogenase B subunits, which catalyze the reduction of CO2 to formate during hydrogenotrophic methanogenesis, constitutes the most ancient lineage. Our analysis also provides robust support for selenocysteine as the ancestral ligand for the Mo/W atom. Finally, we demonstrate that anaerobic arsenite oxidase and respiratory arsenate reductase catalytic subunits represent a more ancient lineage of DMSORs compared to aerobic arsenite oxidase catalytic subunits, which evolved from the assimilatory nitrate reductase lineage. This provides substantial support for an active arsenic biogeochemical cycle on the anoxic Archean Earth. Our work emphasizes that the use of chalcophilic elements as substrates as well as the Mo/W ligand in DMSORs has indelibly shaped the diversification of these enzymes through deep time.


Assuntos
Archaea/enzimologia , Proteínas Arqueais/metabolismo , Arsênico/metabolismo , Bactérias/enzimologia , Proteínas de Bactérias/metabolismo , Proteínas com Ferro-Enxofre/metabolismo , Metano/metabolismo , Oxirredutases/metabolismo , Selênio/metabolismo , Evolução Molecular , Filogenia
16.
Artigo em Inglês | MEDLINE | ID: mdl-32698366

RESUMO

Chronic arsenic (As) exposure is a critical public health issue. The As metabolism can be influenced by many factors. The objective of this study is to verify if these factors influence As metabolism in four Italian areas affected by As pollution. Descriptive analyses were conducted on 271 subjects aged 20-49 in order to assess the effect of each factor considered on As methylation. Percentages of metabolites of As in urine, primary and secondary methylation indexes were calculated as indicators for metabolic capacity. The results indicate that women have a better methylation capacity (MC) than men, and drinking As-contaminated water from public aqueducts is associated with poorer MC, especially in areas with natural As pollution. In areas with anthropogenic As pollution occupational exposure is associated with a higher MC while smoking with a poorer MC. Dietary habits and genetic characteristics are probably implicated in As metabolism. BMI, alcohol consumption and polymorphism of the AS3MT gene seem not to influence As MC. Arsenic metabolism may be affected by various factors and in order to achieve a comprehensive risk assessment of As-associated disease, it is crucial to understand how these factors contribute to differences in As metabolism.


Assuntos
Intoxicação por Arsênico/metabolismo , Arsênico/metabolismo , Exposição Ambiental/efeitos adversos , Poluentes Ambientais/metabolismo , Adulto , Arsênico/análise , Intoxicação por Arsênico/etiologia , Poluentes Ambientais/efeitos adversos , Feminino , Humanos , Itália , Masculino , Metilação , Pessoa de Meia-Idade , Exposição Ocupacional , Poluição da Água , Adulto Jovem
17.
Chem Biol Interact ; 327: 109162, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32524993

RESUMO

Hundreds of millions of people worldwide are exposed to unacceptable levels of carcinogenic inorganic arsenic. Animal models have shown that selenium and arsenic are mutually protective through the formation and elimination of the seleno-bis(S-glutathionyl) arsinium ion [(GS)2AsSe]-. Consistent with this, human selenium deficiency in arsenic-endemic regions is associated with arsenic-induced disease, leading to the initiation of human selenium supplementation trials. In contrast to the protective effect observed in vivo, in vitro studies have suggested that selenite increases arsenite cellular retention and toxicity. This difference might be explained by the rapid conversion of selenite to selenide in vivo. In the current study, selenite did not protect the human hepatoma (HepG2) cell line against the toxicity of arsenite at equimolar concentrations, however selenide increased the IC50 by 2.3-fold. Cytotoxicity assays of arsenite + selenite and arsenite + selenide at different molar ratios revealed higher overall mutual antagonism of arsenite + selenide toxicity than arsenite + selenite. Despite this protective effect, in comparison to 75Se-selenite, HepG2 cells in suspension were at least 3-fold more efficient at accumulating selenium from reduced 75Se-selenide, and its accumulation was further increased by arsenite. X-ray fluorescence imaging of HepG2 cells also showed that arsenic accumulation, in the presence of selenide, was higher than in the presence of selenite. These results are consistent with a greater intracellular availability of selenide relative to selenite for protection against arsenite, and the formation and retention of a less toxic product, possibly [(GS)2AsSe]-.


Assuntos
Arsenitos/toxicidade , Substâncias Protetoras/farmacologia , Ácido Selenioso/farmacologia , Compostos de Selênio/farmacologia , Arsênico/metabolismo , Arsenitos/metabolismo , Células Hep G2 , Humanos , Inativação Metabólica/efeitos dos fármacos , Substâncias Protetoras/metabolismo , Radioisótopos/metabolismo , Ácido Selenioso/metabolismo , Selênio/metabolismo , Compostos de Selênio/metabolismo , Radioisótopos de Selênio/metabolismo
18.
Ecotoxicol Environ Saf ; 201: 110735, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32480163

RESUMO

Methyl jasmonate (Me-JA) is a plant growth regulator known for modulating plant responses to various abiotic and biotic stresses. The unavoidable arsenic (As) contamination in rice (Oryza sativa) results in reduced crop yield and greater carcinogenic risk to humans. The present work examines the significance of Me-JA induced molecular signaling and tolerance towards arsenic toxicity in rice. The arsenite (AsIII; 25 µM) stress hampered the overall growth and development of the rice seedling. However, the co-application (25 µM AsIII+0.25 µM Me-JA) resulted in increased biomass, chlorophyll content, enhanced antioxidant enzyme activities as compared to AsIII treated plants. The co-application also demonstrated a marked decrease in malondialdehyde content, electrolyte leakage and accumulation of total AsIII content (root + shoot) as compared to AsIII treated plants. The co-application also modulated the expression of genes involved in downstream JA signaling pathway (OsCOI, OsJAZ3, OsMYC2), AsIII uptake (OsLsi1, OsLsi2, OsNIP1;1, OsNIP3;1), translocation (OsLsi6, and OsINT5) and detoxification (OsNRAMP1, OsPCS2, and OsABCC2) which revealed the probable adaptive response of the rice plant to cope up arsenic stress. Our findings reveal that Me-JA alleviates AsIII toxicity by modulating signaling components involved in As uptake, translocation, and detoxification and JA signaling in rice. This study augments our knowledge for the future use of Me-JA in improving tolerance against AsIII stress.


Assuntos
Acetatos/farmacologia , Arsênico/toxicidade , Ciclopentanos/farmacologia , Oryza/efeitos dos fármacos , Oxilipinas/farmacologia , Reguladores de Crescimento de Planta/farmacologia , Acetatos/metabolismo , Arsênico/metabolismo , Arsenitos/metabolismo , Arsenitos/toxicidade , Transporte Biológico , Ciclopentanos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Humanos , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Oxilipinas/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Transdução de Sinais/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos
19.
Chemosphere ; 258: 127305, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32563914

RESUMO

Chronic arsenic toxicity has become a global concern due to its adverse pathophysiological outcome and carcinogenic potential. It is already established that arsenic induced reactive oxygen species alters mitochondrial functionality. Major regulatory genes for mitochondrial biogenesis, i.e., PGC1α, Tfam, NRF1and NRF2 are located in the nucleus. As a result, mitochondria-nucleus crosstalk is crucial for proper mitochondrial function. This previous hypothesis led us to investigateinvolvement of epigenetic alteration behindenhanced mitochondrial biogenesis in chronic arsenic exposure. An extensive case-control study was conducted with 390 study participants (unexposed, exposed without skin lesion, exposed with skin lesion and exposed skin tumour) from highly arsenic exposed areas ofWest Bengal, India. Methylation specific PCRrevealed significant promoter hypomethylation oftwo key biogenesis regulatory genes, PGC1αandTfam in arsenic exposed individuals and also in skin tumour tissues. Linear regression analysis indicated significant negative correlation between urinary arsenic concentration and promoter methylation status. Increased expression of biogenesis regulatory genes wasobtained by quantitative real-time PCR analysis. Moreover, altered mitochondrial fusion-fission regulatory gene expression was also observed in skin tumour tissues. miR663, having tumour suppressor gene like function was known to be epigenetically regulated through mitochondrial retrograde signal. Promoter hypermethylation with significantly decreased expression of miR663 was found in skin cancer tissues compared to non-cancerous control tissue. In conclusion, results indicated crucial role of epigenetic alteration in arsenic induced mitochondrial biogenesis and arsenical skin carcinogenesis for the first time. However, further mechanistic studies are necessary for detailed understanding of mitochondria-nucleus crosstalk in arsenic perturbation.


Assuntos
Arsênico/toxicidade , Epigênese Genética , Mitocôndrias/fisiologia , Arsênico/metabolismo , Intoxicação por Arsênico , Carcinogênese/induzido quimicamente , Estudos de Casos e Controles , Metilação de DNA , Epigenômica , Feminino , Humanos , Índia , Masculino , MicroRNAs/metabolismo , Mitocôndrias/metabolismo , Biogênese de Organelas , Regiões Promotoras Genéticas , Dermatopatias/induzido quimicamente , Neoplasias Cutâneas/induzido quimicamente
20.
Artigo em Inglês | MEDLINE | ID: mdl-32403438

RESUMO

The uptake of As by various plants growing in highly enriched sites was examined in order to identify potential As accumulators and to assess the risk associated with As presence in plant shoots. Representative samples of 13 plant species, together with soil samples, were collected from various sites affected by historical As mining: mine and slag dumps, tailings and contaminated soils with As concentrations in a range 72-193,000 mg/kg. Potentially and actually soluble As forms, extracted with 0.43 M HNO3 and, 1M NH4NO3 were examined in relation to As concentrations in plant roots and shoots. The latter differed strongly among the species and within them and were in the ranges 2.3-9400 mg/kg and 0.5-509 mg/kg, respectively. The majority (over 66%) of plant samples had As shoot concentrations above 4 mg/kg, an upper safe limit for animal fodder. The uptake of As by plants correlated well with total and extractable soil As, though As concentrations in plants could not be predicted based on soil parameters. Equisetum spp. and C. epigejos indicated a particularly strong accumulation of As in shoots, while A. capillaris, and H. lanatus showed a limited As root-to-shoot transfer, apparently associated with species-related tolerance to As.


Assuntos
Arsênico/metabolismo , Mineração , Plantas/metabolismo , Poluentes do Solo/metabolismo , Animais , Biodegradação Ambiental , Polônia , Solo
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