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1.
J Agric Food Chem ; 67(31): 8527-8535, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31298526

RESUMO

l-Valine belongs to the branched-chain amino acids (BCAAs) and is an essential amino acid that is crucial for all living organisms. l-Valine is industrially produced by the nonpathogenic bacterium Corynebacterium glutamicum and is synthesized by the BCAA biosynthetic pathway. Ketol-acid reductoisomerase (KARI) is the second enzyme in the BCAA pathway and catalyzes the conversion of (S)-2-acetolactate into (R)-2,3-dihydroxy-isovalerate, or the conversion of (S)-2-aceto-2-hydroxybutyrate into (R)-2,3-dihydroxy-3-methylvalerate. To elucidate the enzymatic properties of KARI from C. glutamicum (CgKARI), we successfully produced CgKARI protein and determined its crystal structure in complex with NADP+ and two Mg2+ ions. Based on the complex structure, docking simulations, and site-directed mutagenesis experiments, we revealed that CgKARI belongs to Class I KARI and identified key residues involved in stabilization of the substrate, metal ions, and cofactor. Furthermore, we confirmed the difference in the binding of metal ions that depended on the conformational change.


Assuntos
Proteínas de Bactérias/química , Corynebacterium glutamicum/enzimologia , Cetol-Ácido Redutoisomerase/química , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Domínio Catalítico , Corynebacterium glutamicum/química , Corynebacterium glutamicum/genética , Cristalografia por Raios X , Cetol-Ácido Redutoisomerase/genética , Cetol-Ácido Redutoisomerase/metabolismo , Metais/química , Metais/metabolismo , Simulação de Acoplamento Molecular , NADP/química , NADP/metabolismo
2.
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
3.
J Environ Radioact ; 207: 7-14, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31151051

RESUMO

Preliminary values of whole organism concentration ratio (CRwo-soil) were derived for terrestrial vertebrates of an Australian tropical savanna environment. Wildlife groups included bird, bat, ground-dwelling mammal and reptile. Sample data for some of the wildlife groups (bird and bat in particular) were limited. The bird and bat CRwo-soil values were generally lower than the ground-dwelling mammal and reptile CRwo-soil values based on the available data. Arithmetic mean CRwo-soil values for two species of native marsupial and two species of non-native placental were not significantly different (p < 0.05) when tested using a one-way analysis of variance. The results hinted at possible sampling efficiencies for terrestrial vertebrates. However, verification with additional data was recommended. Used cautiously, the CRwo-soil values may assist in environmental assessments of Australian uranium mining sites. They also enhance the available data on radionuclide transfer to wildlife for use internationally.


Assuntos
Monitoramento Ambiental , Poluentes Ambientais/metabolismo , Metais/metabolismo , Radioisótopos/metabolismo , Vertebrados/metabolismo , Animais , Austrália , Pradaria
4.
Environ Sci Pollut Res Int ; 26(23): 23754-23762, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31209755

RESUMO

Environmental pollution can cause metal accumulation in aquatic organisms, but information on metal bioaccumulation in wild fish from coal mining areas is limited. We investigated tissue-specific metal accumulation in six economically important fish species common to Gaotang Lake, China, located in a coal mining area. We also conducted an assessment of potential risks to human health from consumption of these fish. Mean concentrations of arsenic, cadmium, cobalt, copper, mercury, lead, and antimony in the muscle of six fish species were below the corresponding Chinese maximum allowable concentrations except chromium and generally comparable with levels in fish reported by other studies. Tissue distribution patterns suggested that chromium and mercury were easily transported to the muscle, but concentrations of the other six metals were higher in the liver and gills. The daily intake of each metal was estimated at 0.002-0.220 g/day/kg body weight, and the non-carcinogenic health risks associated with the consumption of the fish from Gaotang Lake were acceptable. The results suggest that metal bioaccumulation in wild fish is not high in this coal mining area.


Assuntos
Minas de Carvão , Monitoramento Ambiental , Peixes/metabolismo , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Arsênico/análise , Cádmio/análise , China/epidemiologia , Cromo , Cobre/análise , Exposição Dietética/estatística & dados numéricos , Poluição Ambiental , Brânquias/química , Humanos , Lagos/química , Mercúrio/análise , Metais/análise , Medição de Risco , Alimentos Marinhos
5.
Sci Total Environ ; 685: 332-344, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31176220

RESUMO

The present study assessed the spatial and temporal variations on metal bioaccumulation and biochemical biomarker responses in oysters Crassostrea gasar transplanted to two different sites (S1 and S2) at the Laguna Estuarine System (LES), southern Brazil, over a 45-days period. A multi-biomarker approach was used, including the evaluation of lipid peroxidation (MDA) levels, and antioxidant defense enzymes (CAT, GPx, GR and G6PDH) and phase II biotransformation enzyme (GST) in the gills and digestive gland of oysters in combination with the quantification of Al, Cd, Cu, Pb, Fe, Ni and Zn in both tissues. The exposed oysters bioaccumulated metals, especially Al, Cd and Zn in gills and digestive gland, with most prominent biomarker responses in the gills. Results showed that GPx, GR and G6PDH enzymes offered an increased and coordinated response possibly against metal (Zn, Ni, Cd and Cu) contamination in gills. GST was inversely correlated to Cd levels, being its activity significantly lowered over the 45-d exposure periods at S2. On contrary, in digestive gland GST was slightly positively correlated to Cd, revealing a compensatory mechanism between tissues to protect oysters' cells against oxidative damages, since MDA levels also decreased. CAT also appeared to be involved in the cellular protection against oxidative stress, being increased in gills. However, CAT was negatively correlated to Al levels, which might suggest a possible inhibitory effect of this metal in the gills of C. gasar. Differences between tissues were evident by the Integrative Biomarker Responses version 2 (IBRv2) indexes, which showed different pattern between tissues when studying the sites and exposure periods separately. This study provided evidence for the effectiveness of using a multi-biomarker approach in oyster C. gasar to monitor estuarine metal pollution.


Assuntos
Crassostrea/fisiologia , Monitoramento Ambiental , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Brasil , Estuários , Brânquias/metabolismo , Inativação Metabólica , Peroxidação de Lipídeos/efeitos dos fármacos , Metais/toxicidade , Oxirredução , Estresse Oxidativo/fisiologia , Poluentes Químicos da Água/toxicidade
6.
Prep Biochem Biotechnol ; 49(7): 718-726, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31050583

RESUMO

A propanol-tolerant neutral protease was purified and characterized from Bacillus sp. ZG20 in this study. This protease was purified to homogeneity with a specific activity of 26,655 U/mg. The recovery rate and purification fold of the protease were 13.7% and 31.5, respectively. The SDS-PAGE results showed that the molecular weight of the protease was about 29 kDa. The optimal temperature and pH of the protease were 45 °C and 7.0, respectively. The protease exhibited a good thermal- and pH stability, and was tolerant to 50% propanol. Mg2+, Zn2+, K+, Na+ and Tween-80 could improve its activity. The calculated Km and Vmax values of the protease towards α-casein were 12.74 mg/mL and 28.57 µg/(min mL), respectively. This study lays a good foundation for the future use of the neutral protease from Bacillus sp. ZG20.


Assuntos
1-Propanol/metabolismo , Bacillus/enzimologia , Peptídeo Hidrolases/metabolismo , Bacillus/química , Bacillus/metabolismo , Detergentes/metabolismo , Eletroforese em Gel de Poliacrilamida , Estabilidade Enzimática , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Íons/metabolismo , Metais/metabolismo , Peptídeo Hidrolases/química , Peptídeo Hidrolases/isolamento & purificação , Solventes/metabolismo , Especificidade por Substrato , Tensoativos/metabolismo , Temperatura Ambiente
7.
Biosci Biotechnol Biochem ; 83(7): 1354-1361, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31056006

RESUMO

Pleurotus salmoneostramineus is a pink mushroom. This pink color is a protein and forms a complex with 3H-indol-3-one. The gene encoding the pink-colored protein from P. salmoneostramineus (PsPCP) was cloned, and its sequence was elucidated as a 681-bp. The ORF encodes 226 amino acid residues. The amino acid sequence of the protein did not show any significant homology in the DDBJ/EMBL/GenBank databases. Recombinant PsPCP was expressed as the soluble form in E. coli. The reaction mixture of purified recombinant PsPCP and 3H-indol-3-one showed a pink color as the native pigment. A real-time PCR analysis revealed the strong expression of PsPCP in the primordium formation stage of the life cycle of the fungus; however, its expression decreased with the maturation of the fruit body. A comparison of PsPCP gene expression profiles between two strains revealed high levels in the dark-colored strain.


Assuntos
Cor , Proteínas Fúngicas/genética , Pleurotus/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Escherichia coli/genética , Proteínas Fúngicas/química , Concentração de Íons de Hidrogênio , Metais/metabolismo
8.
Chemosphere ; 231: 194-206, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31129400

RESUMO

Among reptiles, freshwater turtle species have high potential for metal accumulation because of their long lifespan or their aquatic and terrestrial habits. In order to monitor metal bioaccumulation, determine potential toxic effects, and investigate tools for non-invasive metal sampling in reptiles, we studied lead (Pb) and mercury (Hg) accumulation in Mediterranean pond turtles (Mauremys leprosa) inhabiting two former mining areas, one of them with high environmental concentrations of Pb (Sierra Madrona-Alcudia Valley district) and the other one with high environmental concentrations of Hg (Almadén district). Individuals from the Pb mining area showed mean blood concentrations (i.e. 5.59 µg Pb/g dry weight, d.w.) that were higher than those measured in other populations. Blood Hg concentrations were highest (8.83 µg Hg/g d.w.) in the site close to the former Hg mines, whereas blood Hg concentrations in terrapins from another site of Almadén district, located ∼28 km downstream, were not different from locations at the non-mining area. Animals from the Pb-contaminated site showed evidence of oxidative stress, whereas those from the Hg-contaminated site showed increased activity of the antioxidant enzyme glutathione peroxidase, as well as reduced circulating levels of the main endogenous antioxidant peptide, glutathione. Concentrations measured in feces and carapace scutes were useful indicators to monitor blood concentrations of Pb, but not of Hg. Our results provide evidence of the usefulness of freshwater turtles as sentinels of chronic metal pollution, and validate non-invasive tools to advance Pb monitoring in reptiles.


Assuntos
Monitoramento Ambiental/métodos , Metais/metabolismo , Mineração , Tartarugas/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Poluição Ambiental , Água Doce , Região do Mediterrâneo , Mercúrio/análise , Mercúrio/metabolismo , Metais/análise , Tanques/química
9.
Chemosphere ; 227: 462-469, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31003131

RESUMO

Different light combinations can improve phytoremediation efficiency by increasing the biomass yield and metal concentrations of plants. However, there has been rare research of using hyperaccumulators to change metal fractions and its possible leaching risk during phytoremediation. It was investigated in this study the impacts of different intensities of blue and red light mixed on the biomass production and metal uptake of Noccaea caerulescens and the changes of water soluble and exchangeable metal fractions in soil. The biomass of N. caerulescens increased with light intensity. The increment was relatively slow at 50 m-2 s-1, dramatically increased at 200 m-2 s-1 and decreased significantly when beyond. Under optimal light condition, N. caerulescens produced less biomass than Thlaspi arvense, but the former is significantly more efficient in phytoremediation than the latter because it can accumulate significantly more metals per unit biomass. Without light irradiation, N. caerulescens can deteriorate the potential leaching risk of Cu and Pb by increasing their water soluble and exchangeable fractions in soil comparing with T. arvense. The proportions of bioavailable fractions did not change under the treatment of light at an intensity of 50 m-2 s-1, but decreased obviously when the intensity exceeded 100 m-2 s-1. Therefore, using hyperaccumulator for multiple metal contaminated soil remediation should be conducted with caution since the species can mobilize all metals in soil but only hyperaccumulate part of them, and proper intensity of light can improve the phytoremediation effect and alleviate the leaching risk through decreasing bioactive metal fractions in soil.


Assuntos
Biodegradação Ambiental , Brassicaceae/metabolismo , Metais/metabolismo , Poluentes do Solo/metabolismo , Biomassa , Metais/análise , Metais/química , Processos Fotoquímicos , Solo , Poluentes do Solo/análise , Poluentes do Solo/química , Thlaspi
10.
Int J Mol Sci ; 20(8)2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30995804

RESUMO

Salinity is a major abiotic stress that limits maize yield and quality throughout the world. We investigated phosphoproteomics differences between a salt-tolerant inbred line (Zheng58) and a salt-sensitive inbred line (Chang7-2) in response to short-term salt stress using label-free quantitation. A total of 9448 unique phosphorylation sites from 4116 phosphoproteins in roots and shoots of Zheng58 and Chang7-2 were identified. A total of 209 and 243 differentially regulated phosphoproteins (DRPPs) in response to NaCl treatment were detected in roots and shoots, respectively. Functional analysis of these DRPPs showed that they were involved in carbon metabolism, glutathione metabolism, transport, and signal transduction. Among these phosphoproteins, the expression of 6-phosphogluconate dehydrogenase 2, pyruvate dehydrogenase, phosphoenolpyruvate carboxykinase, glutamate decarboxylase, glutamate synthase, l-gulonolactone oxidase-like, potassium channel AKT1, high-affinity potassium transporter, sodium/hydrogen exchanger, and calcium/proton exchanger CAX1-like protein were significantly regulated in roots, while phosphoenolpyruvate carboxylase 1, phosphoenolpyruvate carboxykinase, sodium/hydrogen exchanger, plasma membrane intrinsic protein 2, glutathione transferases, and abscisic acid-insensitive 5-like protein were significantly regulated in shoots. Zheng58 may activate carbon metabolism, glutathione and ascorbic acid metabolism, potassium and sodium transportation, and the accumulation of glutamate to enhance its salt tolerance. Our results help to elucidate the mechanisms of salt response in maize seedlings. They also provide a basis for further study of the mechanism underlying salt response and tolerance in maize and other crops.


Assuntos
Fosfoproteínas/metabolismo , Proteínas de Plantas/metabolismo , Estresse Salino , Tolerância ao Sal , Zea mays/fisiologia , Peróxido de Hidrogênio/metabolismo , Metais/metabolismo , Raízes de Plantas/fisiologia , Prolina/metabolismo , Mapas de Interação de Proteínas , Plântula/fisiologia
11.
Int J Mol Sci ; 20(8)2019 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31013856

RESUMO

The brain has a unique biological complexity and is responsible for important functions in the human body, such as the command of cognitive and motor functions. Disruptive disorders that affect this organ, e.g. neurodegenerative diseases (NDDs), can lead to permanent damage, impairing the patients' quality of life and even causing death. In spite of their clinical diversity, these NDDs share common characteristics, such as the accumulation of specific proteins in the cells, the compromise of the metal ion homeostasis in the brain, among others. Despite considerable advances in understanding the mechanisms of these diseases and advances in the development of treatments, these disorders remain uncured. Considering the diversity of mechanisms that act in NDDs, a wide range of compounds have been developed to act by different means. Thus, promising compounds with contrasting properties, such as chelating agents and metal-based drugs have been proposed to act on different molecular targets as well as to contribute to the same goal, which is the treatment of NDDs. This review seeks to discuss the different roles and recent developments of metal-based drugs, such as metal complexes and metal chelating agents as a proposal for the treatment of NDDs.


Assuntos
Quelantes/farmacologia , Desenvolvimento de Medicamentos , Metais/metabolismo , Doenças Neurodegenerativas/etiologia , Doenças Neurodegenerativas/metabolismo , Amiloide/química , Amiloide/metabolismo , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Animais , Quelantes/química , Quelantes/uso terapêutico , Reposicionamento de Medicamentos , Humanos , Metais/química , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/patologia , Relação Estrutura-Atividade
12.
Sci Total Environ ; 675: 151-164, 2019 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-31026639

RESUMO

The biomagnification of metals (Cd, Co, Cr, Cu, Fe, Mn, Pb and Zn) and the metalloid As in aquatic systems is a global health concern. In this study, concentrations of fatty acid biomarkers in zooplankton were analyzed from the Pearl River, South China between September 2016 and July 2017. The objective was to examine how particulate matter, algae and bacteria food sources affect metal bioaccumulation using fatty acid facilitation. In the zooplankton fraction, positive correlations were observed between Pb concentration and Eicosapentaenoic acid (EPA), Zn and Docosahexaenoic acid (DHA) (diatoms and Cryptophyceae biomarkers), Fe with Palmitoleic acid (C16:1n-7, diatom marker), and a weak association of Mn with α-linolenic acid (C18:3n-3). Cu concentration in the zooplankton increased significantly with an endogenous biotic biomarker Stearic acid (C18:0, bacteria biomarker), while Cd concentrations increased with increasing Oleic acid (C18:1n-9, green alga biomarker) concentration. There was a positive correlation between Cr concentration and the sum of Pentadecylic and Margaric acids (C15:0 + C17:0, bacteria biomarkers). Seven of the nine metals examined showed associations with fatty acids in the zooplankton. The bioaccumulation of Co, Cu, Pb, Fe, Mn and Zn concentration was correlated to the individual biomasses of Brachionus calyciflorus, Filinia longiseta, Schmackeria forbesi, Limnoithona sinenisis, Thermocyclops brevifurcatus, and Diaphanosoma dubium. For selected zooplankton taxa, the algal biomasses of Euglenophyceae, Chlorophyceae, Cryptophyceae, and Bacillariophyceae were correlated. Zooplankton were affected by selected species of phytoplankton and bacteria numbers in the Pearl River. These results show that metal accumulation in zooplankton is not only correlated with diet but is also in part, species specific with metal type. Thus, the bioaccumulation or scavenging of metals across trophic levels is a fundamental and complex component of metal cycling in aquatic environments.


Assuntos
Monitoramento Ambiental , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Bactérias , China , Dieta , Exposição Dietética , Metais/análise , Rios/química , Poluentes Químicos da Água/análise , Zooplâncton/fisiologia
13.
Exp Oncol ; 41(1): 20-25, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30932415

RESUMO

AIM: To investigate the content of essential elements (EE): copper, zinc, magnesium, iron and calcium and the evaluation of the activity of metal-containing enzymes - ceruloplasmin (CP), myeloperoxidase (MPO) and the content of transferrin (TF) in blood plasma (BP) and tumor tissue (TT) of animals with Walker-256 carcinosarcoma treated with lactoferrin (LF). MATERIALS AND METHODS: The study of the EE content and the activity of the abovementioned enzymes was carried out on rats with Walker-256 carcinosarcoma treated with LF at the doses of 1 and 10 mg/kg of body weight. The quantitative content of EE in BP and TT of animals was determined using the inductively coupled plasma atomic emission spectroscopy (ICP-AES). Determination of CP activity, content of TF and hemochromes was performed using the method of electron paramagnetic resonance (EPR), and MPO - by unified biochemical method. RESULTS: The introduction of LF at the doses of 1 and 10 mg/kg resulted in a decrease in the ratio of Cu/Zn in BP and even more expressed decrease of Ca/Mg ratio in TT. Administration of LF, especially at a dose of 10 mg/kg, affected the increase in CP and MPO activity in BP. It has been shown that administration of LF at a dose of 10 mg/kg led to an increase in oxidative products of destruction of the hemoglobin-hemochrom system in the TT, against the background of lowering the TF content. CONCLUSIONS: The administration of LF, especially at a dose of 10 mg/kg, led to metabolic alterations associated with inhibition of the tumor process. The detected modulating effect of LF on the content of the EE and the activity of the CP and MPO may be a basis for correction of the elemental balance in carcinogenesis.


Assuntos
Carcinoma 256 de Walker/metabolismo , Homeostase , Lactoferrina/metabolismo , Metaloproteínas/metabolismo , Metais/metabolismo , Nutrientes/metabolismo , Animais , Biomarcadores , Ratos
14.
ScientificWorldJournal ; 2019: 8456371, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30992695

RESUMO

The importance of phytoplankton is high in transformation of substances in aquatic ecosystems and in formation of suspension's material structure. Its main functions are consumption of the dissolved biogenic components and chemical elements and their conversion to a firm phase. The article is devoted to the bioaccumulation of microelements by phytoplankton in the ecosystem of the Azov Sea. The fact that the algal biomass during the periods of blooming in the sea reaches 1,400 g/l makes this study especially urgent. The authors define the rates of biogeochemical cycle and the intensity of chemical elements' consumption and also investigate the role of phytoplankton in the formation chemical peculiarities of bottom deposits and its involvement in sedimentogenesis in the Azov Sea. The cause of the reduced trace element content in bottom deposits relatively to suspended material is established. It is noted that the amount of some elements annually consumed by algae of the Azov Sea is up to 75% from their maximum delivery by terrigenous material.


Assuntos
Fitoplâncton/fisiologia , Ecossistema , Metais/metabolismo , Oceanos e Mares , Fitoplâncton/química , Fitoplâncton/metabolismo , Federação Russa , Espectrofotometria Atômica
15.
Environ Sci Pollut Res Int ; 26(14): 14414-14425, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30868460

RESUMO

Production of acid mine drainage (AMD) and acid sulfate soils is one of the most concerning environmental consequences associated with mining activities. Implementation of appropriate post-mining AMD management practices is very important to minimize environmental impacts such as high soil acidity, soil erosion, and metal leachability. The objective of this study was to develop a cost-effective and environment-friendly "green" technology for the treatment of AMD-impacted soils. This study utilized the metal-binding and acid-neutralizing capacity of an industrial by-product, namely drinking water treatment residuals (WTRs), and the extensive root system of a metal hyper-accumulating, fast-growing, non-invasive, high-biomass perennial grass, vetiver (Chrysopogon zizanioides L.) to prevent soil erosion. Aluminum (Al)-based and calcium (Ca)-based WTRs were used to treat AMD-impacted soil collected from the Tab-Simco coal mine in Carbondale, IL. Tab-Simco is an abandoned coal mine, with very acidic soil containing a number of metals and metalloids such as Fe, Ni, Zn, Pb, and As at high concentrations. A 4-month-long greenhouse column study was performed using 5% and 10% w/w WTR application rates. Vetiver grass was grown on the soil-WTR mixed media. Turbidity and total suspended solid (TSS) analysis of leachates showed that soil erosion decreased in the soil-WTR-vetiver treatments. Difference in pH of leachate samples collected from control (3.06) and treatment (6.71) columns at day 120 indicated acidity removal potential of this technology. A scaled-up simulated field study was performed using 5% WTR application rate and vetiver. Soil pH increased from 2.69 to 7.2, and soil erosion indicators such as turbidity (99%) and TSS (95%) in leachates were significantly reduced. Results from the study showed that this "green" reclamation technique has the potential to effectively treat AMD-impacted soils.


Assuntos
Recuperação e Remediação Ambiental/métodos , Mineração , Poluentes do Solo/análise , Ácidos , Biodegradação Ambiental , Biomassa , Vetiveria/metabolismo , Metais/análise , Metais/metabolismo , Solo , Poluentes do Solo/metabolismo , Sulfatos/análise
16.
Chemosphere ; 224: 111-119, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30818189

RESUMO

In this investigation, we assessed the effects of Cu and/or Cd excess on physiological and metabolic processes of the widespread seagrass Zostera marina. Adult were exposed to low Cd and Cu (0.89 and 0.8 µM, respectively) and high Cd and Cu (8.9 and 2.4 µM, respectively) for 6 d at: Control conditions; low Cu; high Cu; low Cd; high Cd; low Cd and low Cu; and high Cd and high Cu. Photosynthetic performance decreased under single and combined treatments, although effects were more negative under Cu than Cd. Total Cu accumulation was higher than Cd, under single and combined treatments; however, their accumulation was generally lower when applied together, suggesting competition among them. Levels of glutathione (GSH) and phytochelatins (PCs) followed patterns similar to metal accumulation, with up to PC5, displaying adaptations in tolerance. A metallothionein (MET) gene showed upregulation only at high Cd, low Cu, and high Cu. The expression of the enzymes glutathione reductase (GR), ascorbate peroxidase (APX), and catalase (CAT) was greatest at high Cu, and at high Cd and Cu together; the highest expression was under Cu, alone and combined. Both metals induced upregulation of the DNA methyltransferases CMT3 and DRM2, with the highest expression at single Cu. The DNA demethylation ROS1 was overexpressed in treatments containing high Cu, suggesting epigenetic modifications. The results show that under copper and/or cadmium, Z. marina was still biologically viable; certainly based, at least in part, on the induction of metal chelators, antioxidant defences and methylation/demethylation pathways of gene regulation.


Assuntos
Antioxidantes/metabolismo , Cádmio/farmacologia , Cobre/farmacologia , Metilação de DNA/efeitos dos fármacos , Metais/metabolismo , Fitoquelatinas/metabolismo , Zosteraceae/efeitos dos fármacos , Redes Reguladoras de Genes , Zosteraceae/enzimologia , Zosteraceae/metabolismo
17.
Environ Sci Pollut Res Int ; 26(12): 11975-11987, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30825127

RESUMO

Cephalopods are important in the diets of humans and many other apex predators, and can play an important role in the bioaccumulation of metals. In this study, metal concentrations were analysed in the commercially and ecologically important southern arrow squid, Nototodarus sloanii (Gray 1849), from a heavily targeted fisheries area on New Zealand's Chatham Rise. A variety of tissue types were compared in order to assess the bioaccumulation in edible tissues (mantle and arms) and other organs (digestive gland, kidney, and hearts). Although metal concentrations varied among tissue types, the highest concentrations were found in the digestive gland (for Cd, Cu, Fe, Ni, Zn) and branchial hearts (for Cr, U). We report the first Cd concentrations for N. sloanii from the Chatham Rise, with mean values of 3.11 µg. g-1 in the mantle and 102.53 µg. g-1 in the digestive gland. Our data suggest that concentrations observed in the mantle tissue (which forms the majority of the muscle tissue) and digestive gland (the primary organ for metal accumulation) can be used to estimate the animal's total body burden for all metals analysed. The toxicological and dietary consequences for predators (including humans) feeding on arrow squid can be inferred from measurements of mass and metal concentration in these tissues. Arrow squid represent an important vector for Cd transfer within the pelagic Chatham Rise food web. These are the first recorded baseline data for metal concentrations for any squid in this oceanic region.


Assuntos
Decapodiformes/metabolismo , Monitoramento Ambiental , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Exposição Dietética/estatística & dados numéricos , Pesqueiros , Cadeia Alimentar , Contaminação de Alimentos/estatística & dados numéricos , Humanos , Metais/análise , Metais Pesados/análise , Nova Zelândia , Oceanos e Mares , Alimentos Marinhos/estatística & dados numéricos , Poluentes Químicos da Água/análise
18.
PLoS Comput Biol ; 15(3): e1006848, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30845144

RESUMO

The unique capability of acetogens to ferment a broad range of substrates renders them ideal candidates for the biotechnological production of commodity chemicals. In particular the ability to grow with H2:CO2 or syngas (a mixture of H2/CO/CO2) makes these microorganisms ideal chassis for sustainable bioproduction. However, advanced design strategies for acetogens are currently hampered by incomplete knowledge about their physiology and our inability to accurately predict phenotypes. Here we describe the reconstruction of a novel genome-scale model of metabolism and macromolecular synthesis (ME-model) to gain new insights into the biology of the model acetogen Clostridium ljungdahlii. The model represents the first ME-model of a Gram-positive bacterium and captures all major central metabolic, amino acid, nucleotide, lipid, major cofactors, and vitamin synthesis pathways as well as pathways to synthesis RNA and protein molecules necessary to catalyze these reactions, thus significantly broadens the scope and predictability. Use of the model revealed how protein allocation and media composition influence metabolic pathways and energy conservation in acetogens and accurately predicted secretion of multiple fermentation products. Predicting overflow metabolism is of particular interest since it enables new design strategies, e.g. the formation of glycerol, a novel product for C. ljungdahlii, thus broadening the metabolic capability for this model microbe. Furthermore, prediction and experimental validation of changing secretion rates based on different metal availability opens the window into fermentation optimization and provides new knowledge about the proteome utilization and carbon flux in acetogens.


Assuntos
Clostridium/metabolismo , Metais/metabolismo , Modelos Biológicos , Proteínas/metabolismo , Proteoma , Biocatálise , Carbono/metabolismo , Clostridium/genética , Clostridium/crescimento & desenvolvimento , Metabolismo Energético , Fermentação , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Reprodutibilidade dos Testes
19.
Sci Total Environ ; 669: 481-492, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30884270

RESUMO

Environmental monitoring and risk assessment approaches which include a more holistic view on the effects of pollutants on biota are increasingly sought by regulators and policy makers. Therefore, caged carp juveniles (Cyprinus carpio) were transplanted for 7 weeks along a known Cd and Zn pollution gradient. Metal (Cu, Cd and Zn) accumulation in gill and liver tissue and effect biomarkers (growth, condition factor (CF), hepatosomatic index (HSI), oxygen consumption, swimming capacity, Na+/K+-ATPase activity (NKA) and metallothionein (MT) levels) were compared. Up to 10-fold higher cadmium concentrations were measured in the gills of the fish at the most polluted locations compared to the laboratory control fish. Similarly, cadmium concentrations in liver tissues of field-exposed fish were significantly higher than those measured in laboratory control fish. Cu and Zn concentrations in the gills were not significantly different between field-exposed and control organisms, whereas higher levels in liver tissues were measured in carps deployed in some locations. Effects on liver MT levels were up to 10 times greater for organisms exposed to the field, whereas no clear effect of the metal exposure on NKA in the gill tissue was observed. A decrease in muscle glycogen stores was observed for all organisms deployed in the field, while liver glycogen levels decreased only in fish exposed to two of the 5 sites compared to the laboratory control fish. Additionally, significant drops in liver protein- and lipid stores were observed. No effect on oxygen consumption rates and swimming capacity was observed. The CF and HSI of caged fish reflected the pollution gradient in the river and considerable loss of weight was observed for fish transplanted in the most polluted site. Overall, this active biomonitoring study successfully revealed differences in metal accumulation, physiological and organismal endpoints as a direct consequence of field exposure.


Assuntos
Carpas/fisiologia , Monitoramento Ambiental/métodos , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Biomarcadores/metabolismo , Cádmio , Brânquias , Rim , Fígado , Metalotioneína/metabolismo , Metais/toxicidade , Músculos , Rios , ATPase Trocadora de Sódio-Potássio/metabolismo , Distribuição Tecidual , Poluentes Químicos da Água/toxicidade , Zinco
20.
Sci Total Environ ; 669: 637-648, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30889451

RESUMO

Within Djibouti (Gulf of Aden), the scalloped hammerhead shark (Sphyrna lewini) and milk shark (Rhizoprionodon acutus) are important components of the artisanal fishery and they are caught to be exported or sold for local consumption. However, little scientific information exists on the contamination load of these species in this area of the world. With global populations of elasmobranchs in decline, understanding the extent of contaminant exposure is critical to future conservation as well as to assess the health risks for consumers of these species. The contaminants analyzed in this study comprised PCB, DDT and trace elements in livers, muscles and fins of both hammerhead sharks and milk sharks. The overall organochlorine compounds (OCs) and trace elements concentrations were similar among the two sharks' species and the pattern of PCB and DDT tissue distribution showed the highest burdens in livers compared with muscles and fins. However, the different accumulation profiles of OCs among shark species suggest species-specific accumulation of these contaminants. The p,p'DDE/∑DDT ratios were equal or slightly higher than the critic value of 0.6, suggesting possible recent inputs of technical DDT in the area. Concentration of trace elements from this study were generally comparable to those found in sharks from other areas of the world and, highlight the wide variation in metal concentrations between species, individuals and tissues. As far as Hg is concerned, scalloped hammerhead sharks showed higher accumulation in muscles compared with milk sharks. Both species showed elevated concentration of Se, which might be related to high Hg levels since Se inhibits Hg toxicity. The potential cancer risk for PCB, Cd, Ni, Cr and As fell within the range of 10-6-10-4, suggesting some concerns for the overall contamination levels in both species. Indeed, consuming of fish involves a mixture of all analyzed elements, and therefore, some potential risk might arise from regularly consuming these species.


Assuntos
Exposição Dietética/estatística & dados numéricos , Alimentos Marinhos/estatística & dados numéricos , Tubarões/metabolismo , Oligoelementos/metabolismo , Poluentes Químicos da Água/metabolismo , Nadadeiras de Animais/metabolismo , Animais , Djibuti , Monitoramento Ambiental , Humanos , Hidrocarbonetos Clorados/metabolismo , Mercúrio/metabolismo , Metais/metabolismo , Músculos/metabolismo
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