Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 14.903
Filtrar
1.
J Agric Food Chem ; 67(35): 9877-9884, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31398030

RESUMO

Heavy metal contaminants and nutrient deficiencies in soil negatively affect crop growth and human health. The plant cadmium resistance (PCR) protein transports heavy metals. The abundance of PCR is correlated with that of cell number regulator (CNR) protein, and the two proteins have similar conserved domains. Hence, CNR might also participate in heavy metal transport. We isolated and analyzed TaCNR5 from wheat (Triticum aestivum). The expression level of TaCNR5 in the shoots of wheat increased under cadmium (Cd), zinc (Zn), or manganese (Mn) treatments. Transgenic plants expressing TaCNR5 showed enhanced tolerance to Zn and Mn. Overexpression of TaCNR5 in Arabidopsis increased Cd, Zn, and Mn translocation from roots to shoots. The concentrations of Zn and Mn in rice grains were increased in transgenic plants expressing TaCNR5. These roles of TaCNR5 in the translocation and distribution of heavy metals mean that it has potential as a genetic biofortification tool to fortify cereal grains with micronutrients.


Assuntos
Manganês/metabolismo , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Triticum/genética , Zinco/metabolismo , Arabidopsis/química , Arabidopsis/genética , Arabidopsis/metabolismo , Biofortificação , Transporte Biológico , Cádmio/análise , Cádmio/metabolismo , Manganês/análise , Oryza/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/química , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Triticum/química , Triticum/metabolismo , Zinco/análise
2.
Bioresour Technol ; 291: 121868, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31357045

RESUMO

To clarify the adsorption behaviors of typical heavy metals onto sludge extracellular polymeric substances (EPS), the adsorption capacities and mechanisms, as well as the contributions of the different EPS components (proteins, humic acids and polysaccharides), to the adsorption of Zn2+, Cu2+ and Cd2+ were separately explored. Overall, proteins exhibited a relatively high adsorption capacity for the three metals ions, followed by humic acid, whereas least for polysaccharides. The adsorption of Cu2+ and Cd2+ onto proteins, humic acid and polysaccharides fit well to the Freundlich isotherm, whereas Langmuir model was the best fit for Zn2+ bindings onto polysaccharides/humic acid. The binding of Cu2+, Zn2+ and Cd2+ onto the three EPS components was exothermically favorable, and significant electrostatic interactions were observed for the heavy metals sorption onto humic acid and proteins. In addition, the effect of metal ions sorption on the spectrum of the proteins, polysaccharides and humic acid was also explored.


Assuntos
Cádmio/química , Cobre/química , Substâncias Húmicas , Polissacarídeos/química , Proteínas/metabolismo , Esgotos , Zinco/química , Adsorção , Cádmio/metabolismo , Cobre/metabolismo , Proteínas/química , Esgotos/química , Zinco/metabolismo
3.
Bioresour Technol ; 291: 121752, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31330494

RESUMO

Intensive and unregulated use of feed additives in China has led to high levels of heavy metals such as copper and zinc in fertilizers, considerable quantities of which find their way into the environment. Studies have shown that composting could significantly decrease the bioavailability of heavy metals. This study was to investigate the effects of addition of biochar and a microbial agent on the morphological changes in copper and zinc during composting. Results show that treatment T8 successfully immobilized 70.36% of copper as a result of biochar addition. Treatment T3 successfully immobilized 40.76% of zinc; transformation of zinc to a higher stable state was found to be closely related to the formation of fulvic and humic acids. Results of fluorescence spectrum analysis also corroborate that the conversion of copper and zinc to forms with higher stability was associated with the formation of fulvic and humic acid-like substances.


Assuntos
Carvão Vegetal/metabolismo , Compostagem , Cobre/metabolismo , Esterco/microbiologia , Zinco/metabolismo , Animais , Suínos
4.
Microbiol Res ; 226: 48-54, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31284944

RESUMO

The Burkholderia pseudomallei complex consists of six phylogenetically related Gram-negative bacterial species that include environmental saprophytes and mammalian pathogens. These microbes possess multiple type VI secretion systems (T6SS) that provide a fitness advantage in diverse niches by translocating effector molecules into prokaryotic and eukaryotic cells in a contact-dependent manner. Several recent studies have elucidated the regulation and function of T6SS-2, a novel contact-independent member of the T6SS family. Expression of the T6SS-2 gene cluster is repressed by OxyR, Zur and TctR and is activated by GvmR and reactive oxygen species (ROS). The last two genes of the T6SS-2 gene cluster encode a zincophore (TseZ) and a manganeseophore (TseM) that are exported into the extracellular milieu in a contact-independent fashion when microbes encounter oxidative stress. TseZ and TseM bind Zn2+ and Mn2+, respectively, and deliver them to bacteria where they provide protection against the lethal effects of ROS. The TonB-dependent transporters that interact with TseZ and TseM, and actively transport Zn2+ and Mn2+ across the outer membrane, have also been identified. Finally, T6SS-2 provides a contact-independent growth advantage in nutrient limited environments and is critical for virulence in Galleria mellonella larvae, but is dispensable for virulence in rodent models of infection.


Assuntos
Proteínas de Bactérias/genética , Burkholderia pseudomallei/genética , Burkholderia pseudomallei/metabolismo , Manganês/metabolismo , Sistemas de Secreção Tipo VI/genética , Sistemas de Secreção Tipo VI/metabolismo , Zinco/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Burkholderia pseudomallei/classificação , Regulação Bacteriana da Expressão Gênica , Genes Reguladores/genética , Homeostase , Larva , Proteínas de Membrana Transportadoras/genética , Metiltransferases , Família Multigênica , Oxirredução , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Virulência/genética
5.
J Agric Food Chem ; 67(29): 8096-8106, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31260296

RESUMO

Field experiments were conducted on wheat to study the effects of foliar-applied iodine(I) alone, Zn (zinc) alone, and a micronutrient cocktail solution containing I, Zn, Se (selenium), and Fe (iron) on grain yield and grain concentrations of micronutrients. Plants were grown over 2 years in China, India, Mexico, Pakistan, South Africa, and Turkey. Grain-Zn was increased from 28.6 mg kg-1 to 46.0 mg-1 kg with Zn-spray and 47.1 mg-1 kg with micronutrient cocktail spray. Foliar-applied I and micronutrient cocktail increased grain I from 24 µg kg-1 to 361 µg kg-1 and 249 µg kg-1, respectively. Micronutrient cocktail also increased grain-Se from 90 µg kg-1 to 338 µg kg-1 in all countries. Average increase in grain-Fe by micronutrient cocktail solution was about 12%. The results obtained demonstrated that foliar application of a cocktail micronutrient solution represents an effective strategy to biofortify wheat simultaneously with Zn, I, Se and partly with Fe without yield trade-off in wheat.


Assuntos
Biofortificação/métodos , Produção Agrícola/métodos , Iodo/metabolismo , Ferro/metabolismo , Selênio/metabolismo , Triticum/metabolismo , Zinco/metabolismo , China , Fertilizantes/análise , Índia , Iodo/análise , Ferro/análise , México , Micronutrientes/análise , Micronutrientes/metabolismo , Paquistão , Folhas de Planta/química , Folhas de Planta/metabolismo , Sementes/química , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Selênio/análise , África do Sul , Triticum/química , Triticum/crescimento & desenvolvimento , Turquia , Zinco/análise
6.
Sci Total Environ ; 690: 867-877, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31302551

RESUMO

Fishery targeted species living in estuaries face multiple anthropogenic pressures including habitat contamination. However, trace metal concentrations in aquatic organisms can be highly variable, making it difficult to interpret accumulation responses. Understanding sources for metal accumulation in these organisms and their biokinetics is important for management of local fisheries and ensuring safety and quality of consumed seafood, particularly in urbanised areas. In this study, we exposed Australian sand clams, school prawns and sand whiting to a combination of cadmium (Cd), manganese (Mn) and zinc (Zn) radioisotopes 1) dissolved in seawater, 2) adsorbed to suspended sediment particles and 3) in radiolabelled food. Sand clams were sensitive to Cd, Mn and Zn uptake and accumulation from all sources because of their filter feeding physiology. Mean Cd and Zn assimilation efficiencies (AE) were higher in clams fed benthic diatoms (51, 43, 63% for Cd, Mn and Zn, respectively) than clams fed an algal flagellate species (22, 32, 33% for Cd, Mn and Zn, respectively). Metal uptake by prawns from seawater was low, whereas assimilation from diet was high (67, 59, 64% mean AEs from Cd, Mn and Zn, respectively). Sand whiting did not accumulate metals from seawater, even after concentrations were increased. Assimilation from diet (labelled prawns) was also low for sand whiting, particularly for Cd and Zn (11, 26, 14% mean AEs from Cd, Mn and Zn, respectively). These results may help explain the persistence of sand whiting in contaminated estuaries. Suspended sediment exposures showed that prawns and fish are less likely than clams to be negatively affected by disturbance events such as floods, which can bring metals into estuaries. The findings of this study have implications for fisheries management, both for protection and remediation of important habitats, and to ensure safe standards for seafood consumption by humans.


Assuntos
Organismos Aquáticos/metabolismo , Pesqueiros/estatística & dados numéricos , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Cádmio/metabolismo , Manganês/metabolismo , Zinco/metabolismo
7.
Bioresour Technol ; 289: 121745, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323724

RESUMO

The status of heavy metals and the P fractions in compost affects their environmental risk. The present study investigated the effects of different initial carbon to nitrogen (C/N) ratios (15, 22, 27) on redistribution of Cu, Zn, and P fractions during composting. The results showed that the composting process transformed Cu, Zn and P from mobile fractions to more stable fractions. Compost with an initial C/N of 22 showed the most effective immobilization of Cu, Zn and P because of yielding greatest degree of polymerization. Multivariate statistical analysis identified organic matter as the most critical factor for explaining the redistribution of Cu, Zn, and P fractions in composting. However, the degree of organic matter degradation (organic matter content and Humic acid/Fulvic acid) better explained the change of bioavailability factor for Cu and the mobility of P during composting. This research provided guidance for providing technology to reduce environmental risk in compost.


Assuntos
Carbono/metabolismo , Compostagem , Cobre/metabolismo , Nitrogênio/metabolismo , Fósforo/metabolismo , Zinco/metabolismo , Disponibilidade Biológica
8.
Life Sci ; 233: 116697, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31351968

RESUMO

AIMS: The present study investigated if berberine might induce Zrt-Irt-like protein 14 (ZIP14) and affect zinc redistribution to protect intestinal barrier in sepsis. MAIN METHODS: Rodent model of sepsis was induced by cecal ligation and puncture (CLP). Plasma endotoxin was assayed by LAL test and plasma zinc was measured by flame atomic spectrophotometer. Gut mucosal permeability was determined by plasma FITC-dextran. Zinc content and ZIP14 mRNA in gut mucosa were assayed by spectrophotometer and qRT-PCR, respectively. Tight junction integrity of Caco-2 was evaluated by transepithelial electrical resistance (TEER). Tight junction (TJ) protein expression was detected by Western blotting. KEY FINDINGS: Berberine and zinc gluconate pretreatment to CLP rats improved survival rate, reduced plasma endotoxin level, alleviated hypozincemia, increased zinc accumulation and ZIP14 mRNA expression in the intestinal mucosa. Berberine and zinc gluconate pretreatment decreased CLP-elicited intestinal hyperpermeability to FITC-dextran. These effects of berberine in vivo were abolished by AG1024. In vitro, lipopolysaccharide (LPS) repressed zinc transfer into Caco-2 cells exposed to zinc gluconate. Berberine and IGF-I treatment increased ZIP14 protein expression and promoted zinc transfer into Caco-2 cells exposed to zinc gluconate plus LPS. Berberine treatment induced TJ protein (claudin-1 and occludin) and raised TEER in LPS-treated Caco-2 cells. These effects of berberine in vitro were partially inhibited by ZIP14 siRNA. SIGNIFICANCE: The present study reveals that berberine induces ZIP14 expression and affects zinc re- distribution to protect intestinal barrier in sepsis, which is partially linked with the activation of IGF-I signaling.


Assuntos
Berberina/farmacologia , Proteínas de Transporte de Cátions/metabolismo , Coinfecção/prevenção & controle , Gluconatos/farmacologia , Mucosa Intestinal/efeitos dos fármacos , Sepse/prevenção & controle , Tirfostinas/farmacologia , Zinco/metabolismo , Animais , Células CACO-2 , Permeabilidade da Membrana Celular/efeitos dos fármacos , Coinfecção/metabolismo , Coinfecção/microbiologia , Humanos , Masculino , Substâncias Protetoras/farmacologia , Ratos , Ratos Wistar , Sepse/metabolismo , Sepse/microbiologia , Transdução de Sinais/efeitos dos fármacos
9.
Int J Nanomedicine ; 14: 3471-3490, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190805

RESUMO

Background: Zinc-doped hydroxyapatite has been proposed as a graft biomaterial for bone regeneration. However, the effect of zinc on osteoconductivity is still controversial, since the release and resorption of calcium, phosphorus, and zinc in graft-implanted defects have rarely been studied. Methods: Microspheres containing alginate and either non-doped carbonated hydroxyapatite (cHA) or nanocrystalline 3.2 wt% zinc-doped cHA (Zn-cHA) were implanted in critical-sized calvarial defects in Wistar rats for 1, 3, and 6 months. Histological and histomorphometric analyses were performed to evaluate the volume density of newly formed bone, residual biomaterial, and connective tissue formation. Biomaterial degradation was characterized by transmission electron microscopy (TEM) and synchrotron radiation-based X-ray microfluorescence (SR-µXRF), which enabled the elemental mapping of calcium, phosphorus, and zinc on the microsphere-implanted defects at 6 months post-implantation. Results: The bone repair was limited to regions close to the preexistent bone, whereas connective tissue occupied the major part of the defect. Moreover, no significant difference in the amount of new bone formed was found between the two microsphere groups. TEM analysis revealed the degradation of the outer microsphere surface with detachment of the nanoparticle aggregates. According to SR-µXRF, both types of microspheres released high amounts of calcium, phosphorus, and zinc, distributed throughout the defective region. The cHA microsphere surface strongly adsorbed the zinc from organic constituents of the biological fluid, and phosphorus was resorbed more quickly than calcium. In the Zn-cHA group, zinc and calcium had similar release profiles, indicating a stoichiometric dissolution of these elements and non-preferential zinc resorption. Conclusions: The nanometric size of cHA and Zn-cHA was a decisive factor in accelerating the in vivo availability of calcium and zinc. The high calcium and zinc accumulation in the defect, which was not cleared by the biological medium, played a critical role in inhibiting osteoconduction and thus impairing bone repair.


Assuntos
Alginatos/química , Regeneração Óssea , Cálcio/metabolismo , Durapatita/química , Microesferas , Nanopartículas/química , Zinco/química , Zinco/metabolismo , Animais , Materiais Biocompatíveis/química , Disponibilidade Biológica , Regeneração Óssea/efeitos dos fármacos , Carbonatos/química , Morte Celular , Linhagem Celular , Sobrevivência Celular , Feminino , Camundongos , Nanopartículas/ultraestrutura , Ratos Wistar , Crânio/fisiologia , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
10.
BMC Plant Biol ; 19(1): 283, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31248369

RESUMO

BACKGROUND: Metal homeostasis is critical for plant growth, development and adaptation to environmental stresses and largely governed by a variety of metal transporters. The plant ZIP (Zn-regulated transporter, Iron-regulated transporter-like Protein) family proteins belong to the integral membrane transporters responsible for uptake and allocation of essential and non-essential metals. However, whether the ZIP family members mediate metal efflux and its regulatory mechanism remains unknown. RESULTS: In this report, we provided evidence that OsZIP1 is a metal-detoxified transporter through preventing excess Zn, Cu and Cd accumulation in rice. OsZIP1 is abundantly expressed in roots throughout the life span and sufficiently induced by excess Zn, Cu and Cd but not by Mn and Fe at transcriptional and translational levels. Expression of OsZIP-GFP fusion in rice protoplasts and tobacco leaves shows that OsZIP1 resides in the endoplasmic reticulum (ER) and plasma membrane (PM). The yeast (Saccharomyces cerevisiae) complementation test shows that expression of OsZIP1 reduced Zn accumulation. Transgenic rice overexpressing OsZIP1 grew better under excess metal stress but accumulated less of the metals in plants. In contrast, both oszip1 mutant and RNA interference (RNAi) lines accumulated more metal in roots and contributed to metal sensitive phenotypes. These results suggest OsZIP1 is able to function as a metal exporter in rice when Zn, Cu and Cd are excess in environment. We further identified the DNA methylation of histone H3K9me2 of OsZIP1 and found that OsZIP1 locus, whose transcribed regions imbed a 242 bp sequence, is demethylated, suggesting that epigenetic modification is likely associated with OsZIP1 function under Cd stress. CONCLUSION: OsZIP1 is a transporter that is required for detoxification of excess Zn, Cu and Cd in rice.


Assuntos
Cádmio/metabolismo , Proteínas de Transporte de Cátions/genética , Cobre/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Oryza/genética , Proteínas de Plantas/genética , Zinco/metabolismo , Transporte Biológico/efeitos dos fármacos , Proteínas de Transporte de Cátions/química , Proteínas de Transporte de Cátions/metabolismo , Oryza/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Estresse Fisiológico
11.
Plant Sci ; 285: 91-98, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203897

RESUMO

The Arabidopsis oligopeptide transporter AtOPT6 is membrane transport protein that mediated transport of glutathione in both the reduced (GSH) and oxidized (GSSG) forms. In this study, the role of AtOPT6 in glutathione distribution throughout the plant was investigated. We found that transgenic Arabidopsis overexpressing AtOPT6 under the control of a phloem-specific promoter of sucrose-proton symporter 2 (pSUC2), remarkably increased AtOPT6 transcript levels, ranging from 30- to 40-fold in shoots and 6- to 10-fold in roots, relative to the wild type. AtOPT6-overexpressing lines could elevate the foliar glutathione content; however, glutathione content in the phloem did not change. We observed that the ratio of shoot glutathione content to total glutathione content increased in AtOPT6-overexpressing lines, but not in transgenic Arabidopsis with elevated foliar GSH synthesis. These results indicate the possibility that loading and unloading of glutathione in phloem tissues are enhanced in AtOPT6-overexpressing lines under the control of pSUC2. The results of heavy metal analysis revealed that transgenic Arabidopsis overexpressing AtOPT6 under the control of pSUC2 could promote the transport of Zn into shoots as effectively as transgenic Arabidopsis with elevated foliar GSH synthesis, or wild-type plants with exogenous foliar application of GSH.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/metabolismo , Floema/metabolismo , Brotos de Planta/metabolismo , Simportadores/fisiologia , Zinco/metabolismo , Aminoácidos/metabolismo , Glutationa/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
12.
Nat Commun ; 10(1): 2210, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31101807

RESUMO

The core machinery for de novo biosynthesis of iron-sulfur clusters (ISC), located in the mitochondria matrix, is a five-protein complex containing the cysteine desulfurase NFS1 that is activated by frataxin (FXN), scaffold protein ISCU, accessory protein ISD11, and acyl-carrier protein ACP. Deficiency in FXN leads to the loss-of-function neurodegenerative disorder Friedreich's ataxia (FRDA). Here the 3.2 Å resolution cryo-electron microscopy structure of the FXN-bound active human complex, containing two copies of the NFS1-ISD11-ACP-ISCU-FXN hetero-pentamer, delineates the interactions of FXN with other component proteins of the complex. FXN binds at the interface of two NFS1 and one ISCU subunits, modifying the local environment of a bound zinc ion that would otherwise inhibit NFS1 activity in complexes without FXN. Our structure reveals how FXN facilitates ISC production through stabilizing key loop conformations of NFS1 and ISCU at the protein-protein interfaces, and suggests how FRDA clinical mutations affect complex formation and FXN activation.


Assuntos
Liases de Carbono-Enxofre/ultraestrutura , Ataxia de Friedreich/patologia , Proteínas de Ligação ao Ferro/ultraestrutura , Proteínas com Ferro-Enxofre/ultraestrutura , Mitocôndrias/ultraestrutura , Liases de Carbono-Enxofre/isolamento & purificação , Liases de Carbono-Enxofre/metabolismo , Microscopia Crioeletrônica , Ataxia de Friedreich/genética , Ferro/metabolismo , Proteínas de Ligação ao Ferro/isolamento & purificação , Proteínas de Ligação ao Ferro/metabolismo , Proteínas com Ferro-Enxofre/isolamento & purificação , Proteínas com Ferro-Enxofre/metabolismo , Mitocôndrias/metabolismo , Modelos Moleculares , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Enxofre/metabolismo , Zinco/metabolismo
13.
Environ Pollut ; 251: 37-44, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31071631

RESUMO

The toxic potentially toxic metals elements (PTEs) discharged from industrial activities and agricultural practices persistently pose multiple hazards to environment and living organisms. Microbe-assisted phytoremediation provide an effective approach to remediate PTEs-contaminated soils. A phytoextraction process involved the application of Streptomyces pactum (Act12, 1.0, 2.0 and 3.0 g kg-1 dry soil, respectively) alone/jointly with sulfur was executed. The main texture of the tested soil was sandy loam and with a pH 8.27. The obtained results showed that the leaf pigments and plant biomass were improved after the application of the Act12, while the shoot fresh weight, chlorophyll a and chlorophyll b decreased by 57.8, 38.2 and 40.7%, respectively, after treatment with sulfur. Similarly, sulfur application facilitated the malondialdehyde (MDA) production by 18.4-33.6% compared to the control (no amendments). Both peroxidase (POD) and superoxide dismutase (SOD) activities were boosted, while the catalase (CAT) activity was suppressed with Act12 alone/jointly with sulfur treatment. The sulfur combined with elevated Act12 levels notably increased the cadmium (Cd) and zinc (Zn) concentrations both in shoots and roots, while the elemental extraction amount showed the removal efficiency following the order: Act12 alone > control > Act12 jointly with sulfur. Taken together, the results suggested that Streptomyces pactum and sulfur assisted the phytoremediation process, while further studies should be conducted in the field to test practical application.


Assuntos
Antioxidantes/metabolismo , Mostardeira/crescimento & desenvolvimento , Microbiologia do Solo , Poluentes do Solo/toxicidade , Streptomyces/crescimento & desenvolvimento , Enxofre/análise , Biodegradação Ambiental , Biomassa , Cádmio/metabolismo , Cádmio/toxicidade , China , Clorofila A/metabolismo , Fertilizantes/análise , Mineração , Mostardeira/enzimologia , Mostardeira/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Zinco/metabolismo , Zinco/toxicidade
14.
Cell Mol Life Sci ; 76(17): 3301-3310, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31073743

RESUMO

The channel kinase (chanzyme) transient receptor potential melastatin-like 7 (TRPM7) has a unique dual protein structure composed of an ion channel with an α-kinase domain on its C-terminus. In the nervous system, under physiological conditions, TRPM7 contributes to critical neurobiological processes ranging from synaptic transmission to cognitive functions. Following certain pathological triggers, TRPM7 mediates neurotoxicity, neuro-injuries, and neuronal death. Here, we summarize the current knowledge of TRPM7 functions in neuronal systems in health and disease. The molecular mechanisms by which this chanzyme might regulate synaptic and cognitive functions are discussed. We also discuss the lack of knowledge regarding the molecular mechanisms responsible for turning TRPM7 into "a vicious tool" that mediates neuronal death following certain pathological triggers. Some synthetic and natural pharmacological modulators of the TRPM7 channel and its α-kinase are reviewed. We suggest that based on current knowledge, we should reshape our thinking regarding the implications of TRPM7 in neurological and neurodegenerative disorders. Moreover, we propose a paradigm shift concerning the targeting of TRPM7 as a therapeutic approach for treating certain neurological diseases. We agree that TRPM7 overexpression or overactivation may mediate neurodegenerative processes following certain triggers. However, TRPM7 dysfunction and/or downregulation might also be among the pathological changes leading to neurodegeneration. Consequently, further investigations are required before we decide whether blocking or activating the chanzyme is the correct therapeutic approach to treat certain neurological and/or neurodegenerative diseases.


Assuntos
Sistema Nervoso/metabolismo , Doenças Neurodegenerativas/patologia , Canais de Cátion TRPM/metabolismo , Humanos , Magnésio/metabolismo , Doenças Neurodegenerativas/metabolismo , Plasticidade Neuronal , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Canais de Cátion TRPM/antagonistas & inibidores , Canais de Cátion TRPM/genética , Zinco/metabolismo
15.
Ecotoxicol Environ Saf ; 180: 179-184, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31082582

RESUMO

Selenium (Se) and zinc (Zn) are necessary mineral nutrients for human body but millions of people have an inadequate intake of them, and eat food enriched with Se and Zn may minimize these problems. Chinese cabbage is an important food in people's daily life. The aim of this study was to evaluate the effects of single Se, Zn and their combination treatment in soil on their accumulation, antioxidant system and lipid peroxidation in roots and leaves of Chinese cabbage using soil pot culture experiment. When 0.5 mg kg-1 Se +30 mg kg-1 Zn and 1.0 mg kg-1 Se +30 mg kg-1 Zn were spiked in soils, Zn concentrations in roots and leaves of Chinese cabbage were significantly increased (p < 0.05) by 20.2%, 37.8% and 17.9%, 34.1% respectively compared to the treatment of 30 mg kg-1 Zn added, and the latter was significantly higher (p < 0.05) than that of former, indicating Se significantly promoted Zn accumulation. Almost all physiological indexes including POD, SOD, CAT, APX, GR, Chlorophyll a, Chlorophyll b, Carotenoids, MDA and Free proline in the treatments of Se or Zn spiked were significantly improved (p < 0.05) or basically unaffected compared to the control without Se or Zn added. The biomass change trends were similar with these indexes either. These results showed that the addition in soil of Se and Zn significantly increased their accumulation in Chinese cabbage without affected its formal growth. Particularly, the addition of Se promoted Zn accumulation. The conclusions were more important reference for the production practice of cash crop enriched of Se and Zn either.


Assuntos
Brassica/efeitos dos fármacos , Selênio/farmacologia , Solo , Zinco/metabolismo , Antioxidantes/metabolismo , Brassica/enzimologia , Brassica/metabolismo , Carotenoides/metabolismo , Clorofila/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Selênio/metabolismo
16.
Res Vet Sci ; 124: 334-337, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31048181

RESUMO

The aims of the current study were to assess the inclusion levels of grape byproduct replacing jiggs hay in lambs diets and to evaluate signs of copper poisoning. Thirty-four Texel and Corriedale crossbred female lambs were used in a randomized block experimental design. The treatments comprised four levels of grape byproduct (0; 100; 200 and 300 g/kg DM) in replacement of jiggs hay. The diets were adjusted to the same ZnCu ratio (6:1) of the basal diet. Grape byproduct consumption at up to 30%, led to similar weight gain in the different treatments (P = .92), which was suitable for growing lambs. Grape byproduct in the diet had linear effect on GGT (P < .001) and AST (P < .0001) enzymes as well as on total bilirubin (P = .05). In addition, the highest grape byproduct addition showed the highest consumption of hay (P < .01). Hay replacement by grape byproduct at up to 300 g/kg in the DM was satisfactory to weight gain and did not negatively affect feed intake and weight gain of growing lambs. Maintaining zinc:copper ratio in sheep diets is not effective in preventing liver damage caused by increased dietary copper concentrations over a period of 70 days.


Assuntos
Cobre/envenenamento , Intoxicação por Metais Pesados/veterinária , Carneiro Doméstico/fisiologia , Vitis/química , Zinco/metabolismo , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Suplementos Nutricionais/análise , Feminino , Intoxicação por Metais Pesados/prevenção & controle , Zinco/administração & dosagem
17.
Acta Crystallogr D Struct Biol ; 75(Pt 5): 475-487, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31063150

RESUMO

Phosphomannose isomerase (PMI) is a housekeeping enzyme that is found in organisms ranging from bacteria to fungi to mammals and is important for cell-wall synthesis, viability and signalling. PMI is a zinc-dependent enzyme that catalyses the reversible isomerization between mannose 6-phosphate (M6P) and fructose 6-phosphate (F6P), presumably via the formation of a cis-enediol intermediate. The reaction is hypothesized to involve ring opening of M6P, the transfer of a proton from the C2 atom to the C1 atom and between the O1 and O2 atoms of the substrate, followed by ring closure resulting in the product F6P. Several attempts have been made to decipher the role of zinc ions and various residues in the catalytic function of PMI. However, there is no consensus on the catalytic base and the mechanism of the reaction catalyzed by the enzyme. In the present study, based on the structure of PMI from Salmonella typhimurium, site-directed mutagenesis targeting residues close to the bound metal ion and activity studies on the mutants, zinc ions were shown to be crucial for substrate binding. These studies also suggest Lys86 as the most probable catalytic base abstracting the proton in the isomerization reaction. Plausible roles for the highly conserved residues Lys132 and Arg274 could also be discerned based on comparison of the crystal structures of wild-type and mutant PMIs. PMIs from prokaryotes possess a low sequence identity to the human enzyme, ranging between 30% and 40%. Since PMI is important for the virulence of many pathogenic organisms, the identification of catalytically important residues will facilitate its use as a potential antimicrobial drug target.


Assuntos
Aminoácidos/metabolismo , Frutosefosfatos/metabolismo , Manose-6-Fosfato Isomerase/química , Manose-6-Fosfato Isomerase/metabolismo , Manosefosfatos/metabolismo , Salmonella typhimurium/enzimologia , Zinco/metabolismo , Aminoácidos/química , Aminoácidos/genética , Catálise , Domínio Catalítico , Cristalografia por Raios X , Isomerismo , Manose-6-Fosfato Isomerase/genética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Mutação , Conformação Proteica , Especificidade por Substrato , Zinco/química
18.
Int J Mol Sci ; 20(9)2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31058829

RESUMO

Zinc is an essential trace element and plays critical roles in cellular integrity and biological functions. Excess copper induced both oxidative stress and endoplasmic reticulum (ER) stress in liver-derived cultured cells. Excess copper also induced impairment of autophagic flux at the step of autophagosome-lysosome fusion, as well as Mallory-Denk body (MDB)-like inclusion body formation. Zinc ameliorated excess copper-induced impairment of autophagic flux and MDB-like inclusion body formation via the maintenance of ER homeostasis. Furthermore, zinc also ameliorated free fatty acid-induced impairment of autophagic flux. These results indicate that zinc may be able to protect hepatocytes from various ER stress-related conditions.


Assuntos
Estresse do Retículo Endoplasmático , Hepatócitos/metabolismo , Zinco/metabolismo , Apoptose/efeitos dos fármacos , Autofagossomos/metabolismo , Autofagia/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cobre/metabolismo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Humanos , Corpos de Inclusão/metabolismo , Lisossomos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Zinco/farmacologia
19.
Plant Sci ; 283: 416-423, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128713

RESUMO

Glutathione (GSH) is a vital compound involved in several plant metabolic pathways. Our previous study indicated that foliar GSH application can increase zinc (Zn) levels in leafy vegetables. The objective of this study was to determine the mode of action of GSH as it relates to Zn transport from roots to shoots. Two types of transgenic Arabidopsis plants with genes for GSH synthesis, including StGCS-GS or AtGSH1 driven by the leaf-specific promoter of chlorophyll a/b-binding protein (pCab3) gene were generated. Both types of transgenic Arabidopsis plants showed significant increases in shoot GSH concentrations compared to the wild type (WT). Monitoring 65Zn movement by positron-emitting tracer imaging system (PETIS) analysis indicated that the 65Zn amount in the shoots of both types of transgenic Arabidopsis plants were higher than that in the WT. GSH concentration in phloem sap was increased significantly in WT with foliar applications of 10 mM GSH (WT-GSH), but not in transgenic Arabidopsis with elevated foliar GSH synthesis. Both types of transgenic Arabidopsis with elevated foliar GSH synthesis and WT-GSH exhibited increased shoot Zn concentrations and Zn translocation ratios. These results suggest that enhancement of endogenous foliar GSH synthesis and exogenous foliar GSH application affect root-to-shoot transport of Zn.


Assuntos
Arabidopsis/metabolismo , Glutationa/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Zinco/metabolismo , Arabidopsis/genética , Transporte Biológico , Genes de Plantas/genética , Floema/metabolismo , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase em Tempo Real
20.
Plant Sci ; 283: 424-434, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128714

RESUMO

Glutathione is a tripeptide involved in diverse aspects of plant metabolism. We investigated how the reduced form of glutathione, GSH, applied site-specifically to plants, affects zinc (Zn) distribution and behavior in oilseed rape plants (Brassica napus) cultured hydroponically. Foliar-applied GSH significantly increased the Zn content in shoots and the root-to-shoot Zn translocation ratio; furthermore, this treatment raised the Zn concentration in the cytosol of root cells and substantially enhanced Zn xylem loading. Notably, microarray analysis revealed that the gene encoding pectin methylesterase was upregulated in roots following foliar GSH treatment. We conclude that certain physiological signals triggered in response to foliar-applied GSH were transported via sieve tubes and functioned in root cells, which, in turn, increased Zn availability in roots by releasing Zn from their cell wall. Consequently, root-to-shoot translocation of Zn was activated and Zn accumulation in the shoot was markedly increased.


Assuntos
Brassica napus/efeitos dos fármacos , Glutationa/farmacologia , Folhas de Planta/efeitos dos fármacos , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Zinco/metabolismo , Transporte Biológico/efeitos dos fármacos , Brassica napus/metabolismo , Cromatografia Líquida de Alta Pressão , Análise de Sequência com Séries de Oligonucleotídeos , Floema/metabolismo , Folhas de Planta/metabolismo , Xilema/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA