Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.953
Filtrar
1.
Ecotoxicology ; 30(10): 1969-1982, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34505200

RESUMO

Heavy metals accumulated in the environment due to the mining industry may impact on the health of exposed wild animals with consequences at the population level via survival and selection of the most resistant individuals. The detection and quantification of shifts in gene frequencies or in the genetic structure in populations inhabiting polluted sites may be used as early indicators of environmental stress and reveal potential 'candidate gene biomarkers' for environmental health assessment. We had previously observed that specimens of the Greater white-toothed shrew (Crocidura russula) from two heavy metal mines in Southern Portugal (the Aljustrel and the Preguiça mines) carried physiological alterations compared to shrews from an unpolluted site. Here, we further investigated whether these populations showed genetic differences in genes relevant for physiological homeostasis and/or that are associated with pathways altered in animals living under chronic exposure to pollution, and which could be used as biomarkers. We analysed the mitochondrial cytochrome b (Cytb) gene and intronic and/or exonic regions of four nuclear genes: CYP1A1, LCAT, PRPF31, and p53. We observed (1) population differences in allele frequencies, types of variation, and diversity parameters in the Cytb, CYP1A1, and p53 genes; (2) purifying selection of Cytb in the mine populations; (3) genetic differentiation of the two mine populations from the reference by the p53 gene. Adding to our previous observations with Mus spretus, we provide unequivocal evidence of a population effect exerted by the contaminated environment of the mines on the local species of small mammals.


Assuntos
Metais Pesados , Musaranhos , Animais , Biomarcadores , Citocromo P-450 CYP1A1 , Citocromos b , Monitoramento Ambiental , Humanos , Metais Pesados/metabolismo , Metais Pesados/toxicidade , Camundongos , Musaranhos/metabolismo , Proteína Supressora de Tumor p53
2.
Int J Mol Sci ; 22(18)2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34575861

RESUMO

Heavy metal pollution is widespread and persistent, and causes serious harm to the environment. Pseudomonas putida, a representative environmental microorganism, has strong resistance to heavy metals due to its multiple efflux systems. Although the functions of many efflux systems have been well-studied, the relationship between them remains unclear. Here, the relationship between the Czc and Cad systems that are predominantly responsible for cadmium efflux in P. putida KT2440 is identified. The results demonstrated that CzcR3, the response regulator of two-component system CzcRS3 in the Czc system, activates the expression of efflux pump genes czcCBA1 and czcCBA2 by directly binding to their promoters, thereby helping the strain resist cadmium stress. CzcR3 can also bind to its own promoter, but it has only a weak regulatory effect. The high-level expression of czcRS3 needs to be induced by Cd2+, and this relies on the regulation of CadR, a key regulator in the Cad system, which showed affinity to czcRS3 promoter. Our study indicates that the Cad system is involved in the regulation of the Czc system, and this relationship is important for maintaining the considerable resistance to cadmium in P. putida.


Assuntos
Cádmio/química , Farmacorresistência Fúngica , Regulação Fúngica da Expressão Gênica , Pseudomonas putida/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , Citoplasma/metabolismo , Desoxirribonuclease I/metabolismo , Corantes Fluorescentes/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Genes Bacterianos , Chumbo/química , Metais , Metais Pesados/metabolismo , Regiões Promotoras Genéticas/efeitos dos fármacos , Ligação Proteica , Especificidade da Espécie , Zinco/química , beta-Galactosidase/metabolismo
3.
Microbiol Res ; 250: 126811, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34242923

RESUMO

Endophytic and rhizospheric microorganisms associated with six native plants adapted to heavy metal polluted soil from Punta Olímpica and Chahuapampa, located in Callejón de Huaylas mountains, were evaluated as potential candidates for technologies to clean polluted ecosystems. It was selected 14 bacteria and 9 fungi strains by their iron and/or aluminum siderophore production trait, where BEP17-Dm showed higher production. According to the 16S rDNA analysis, bacteria belong to Pseudomonas, Bacillus, and Achromobacter genera, whereas by ITS analysis fungi belong to Talaromyces, Hypoxylon, Tolypocladium, and Penicillium. All bacteria strains tolerated lead (2-8 mM) and eigth tolerated cadmium (1-6 mM); also all fungi tolerated lead (9-70 mM) and cadmium (3-10 mM). Two bacteria and six fungi solubilized cadmium carbonate, while eleven bacteria and two fungi solubilized tricalcium phosphate, where P. japonica BEP18-Dm and B. subtilis BRU16-Sr exhibited higher solubilization index. None strains solubilized lead carbonate. BEP18-Dm produced higher concentration of IAA (53.42 µgml-1); while six bacteria and all fungi strains produced a low concentration of auxins. Medicago sativa seedlings inoculated with BEP17-Dm, BEP18-Dm, or BRU16-Sr showed more surviving percentage under in vitro culture in presence of Cd, Pb (0.5-1.0 mM), or Al (2.5-5.0 mM). Finally, it is the first report of siderophore-producing microorganisms from polluted soil of Callejón de Huaylas highlands, interestedly they displayed metabolic properties useful to enhance phytoremediation and biotechnology application.


Assuntos
Bactérias/metabolismo , Fungos/metabolismo , Metais Pesados/metabolismo , Plantas/microbiologia , Sideróforos/genética , Sideróforos/metabolismo , Poluentes do Solo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodegradação Ambiental , Recuperação e Remediação Ambiental , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Metais Pesados/análise , Peru , Raízes de Plantas/microbiologia , Microbiologia do Solo
4.
Molecules ; 26(14)2021 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-34299474

RESUMO

Lignocellulosic fibers extracted from plants are considered an interesting raw material for environmentally friendly products with multiple applications. This work investigated the feasibility of using hemp- and flax-based materials in the form of felts as biosorbents for the removal of metals present in aqueous solutions. Biosorption of Al, Cd, Co, Cu, Mn, Ni and Zn from a single solution by the two lignocellulosic-based felts was examined using a batch mode. The parameters studied were initial metal concentration, adsorbent dosage, contact time, and pH. In controlled conditions, the results showed that: (i) the flax-based felt had higher biosorption capacities with respect to the metals studied than the hemp-based felt; (ii) the highest removal efficiency was always obtained for Cu ions, and the following order of Cu > Cd > Zn > Ni > Co > Al > Mn was found for both examined biosorbents; (iii) the process was rapid and 10 min were sufficient to attain the equilibrium; (iv) the efficiency improved with the increase of the adsorbent dosage; and (v) the biosorption capacities were independent of pH between 4 and 6. Based on the obtained results, it can be considered that plant-based felts are new, efficient materials for metal removal.


Assuntos
Cannabis/química , Linho/química , Metais Pesados/análise , Metais Pesados/isolamento & purificação , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Lignina/química , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo
5.
Nat Chem ; 13(7): 683-691, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34155376

RESUMO

Mammalian oocytes undergo major changes in zinc content and localization to be fertilized, the most striking being the rapid exocytosis of over 10 billion zinc ions in what are known as zinc sparks. Here, we report that fertilization of amphibian Xenopus laevis eggs also initiates a zinc spark that progresses across the cell surface in coordination with dynamic calcium waves. This zinc exocytosis is accompanied by a newly recognized loss of intracellular manganese. Synchrotron-based X-ray fluorescence and analytical electron microscopy reveal that zinc and manganese are sequestered in a system of cortical granules that are abundant at the animal pole. Through electron-nuclear double-resonance studies, we rule out Mn2+ complexation with phosphate or nitrogenous ligands in intact eggs, but the data are consistent with a carboxylate coordination environment. Our observations suggest that zinc and manganese fluxes are a conserved feature of fertilization in vertebrates and that they function as part of a physiological block to polyspermy.


Assuntos
Fertilização/fisiologia , Metais Pesados/metabolismo , Óvulo/metabolismo , Xenopus laevis/metabolismo , Animais , Embrião não Mamífero/metabolismo , Embrião não Mamífero/ultraestrutura , Exocitose/fisiologia , Fertilização/efeitos dos fármacos , Metais Pesados/farmacologia , Óvulo/efeitos dos fármacos , Óvulo/ultraestrutura
6.
Ecotoxicol Environ Saf ; 220: 112395, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34102394

RESUMO

Copper (Cu), one of the heavy metals, is far beyond the carrying capacity of the environment with Cu mining, industrial wastewater discharging and the use of Cu-containing pesticides. Intaking excess Cu can cause toxic effects on liver, kidney, heart, but few studies report Cu toxicity on brain tissue. It is noteworthy that most toxicity tests are based on rodent models, but large mammals chosen as animal models has no reported. To explore the relationship of the Cu toxicity and mitochondria-mediated apoptosis on hypothalamus in pigs, the content of Cu, histomorphology, mitochondrial related indicators, apoptosis, and AMPK-mTOR signaling pathway were detected. Results showed that Cu could accumulate in hypothalamus and lead to mitochondrial dysfunction, evidenced by the decrease of ATP production, activities of respiratory chain complex I-IV, and mitochondrial respiratory function in Cu-treated groups. Additionally, the genes and proteins expression of Bax, Caspase-3, Cytc in treatment group were higher than control group. Furthermore, the protein level of p-AMPK was enhanced significantly and p-mTOR was declined, which manifested that AMPK-mTOR signaling pathway was activated in Cu-treated groups. In conclusion, this study illuminated that the accumulation of Cu could cause mitochondrial dysfunction, induce mitochondria-mediated apoptosis and activate AMPK-mTOR pathway in hypothalamus.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Cobre/toxicidade , Hipotálamo/efeitos dos fármacos , Metais Pesados/toxicidade , Mitocôndrias/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Animais , Apoptose , Caspase 3/metabolismo , Cobre/metabolismo , Citocromos c/metabolismo , Exposição Ambiental , Hipotálamo/metabolismo , Metais Pesados/metabolismo , Mitocôndrias/metabolismo , Modelos Animais , Transdução de Sinais , Suínos , Proteína X Associada a bcl-2/metabolismo
7.
Ecotoxicol Environ Saf ; 220: 112368, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34082243

RESUMO

A field investigation on the content of heavy metals in soils and dominant plants was conducted in three sites (A<0.5 km, B<1.0 km, C<1.5 km) with different distances of mine tailings. The spatial distribution of heavy metals and the accumulation in plants were compared, and the candidate species for ecosystem restoration were selected. The results indicated that the soil was polluted by chromium (Cr), Cadmium (Cd), copper (Cu), nickel (Ni) in varying degrees, which is 2.07, 2.60, 1.79, and 4.49 times higher than the Class-Ⅱ standard in China. The concentrate of Ni, Cd, and Zinc (Zn) increased, while Cr, Lead (Pb), and Cu decreased with the distance from the mine tailings. 73 species (34 families) were found and mainly herbaceous plants. The concentrate of Cd, Cu, Cr, and Ni in 29 dominant plants were measured and 66.67%, 21.43%, 100%, 47.62% plants exceeded the normal concentration range. Based on the comparative analysis of heavy metal content, bioconcentration factor, and translocation factor in plants, Polygonum capitatum has good phytoextraction ability, Boehmeria nivea, Chrysanthemum indicum, Miscanthus floridulus, Conyza canadensis, Rubus setchuenensis, Senecio scandens, and Arthraxon hispidus showed remarkable phytostabilization abilities of Cr, Cd, Ni, and Cu, which can be used as potential phytoremediation candidate.


Assuntos
Metais Pesados/metabolismo , Mineração , Plantas/metabolismo , Poluentes do Solo/metabolismo , Bioacumulação , Biodegradação Ambiental , China , Metais Pesados/análise , Plantas/classificação , Solo/química , Poluentes do Solo/análise
8.
Ecotoxicol Environ Saf ; 220: 112411, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34111661

RESUMO

This study focused on the effects of eight medicinal plant extracts on Solanum nigrum L. potential to accumulate Cd and Pb from soil. These medicinal plants were common and relatively cheap. The eight 10% water extracts were made from the peel of Citrus reticulata Blanco (PCR), fruit of Phyllanthus emblica L. (FPE), root of Pueraria Lobata (Willd.) Ohwi (RPL), rhizome of Polygonatum sibiricum Red (RPS), root of Astragalus propinquus Schischkin (RAP), bud of Hemerocallis citrina Baroni (BHC), seed of Nelumbo nucifera Gaertn (SNN) and fruit of Prunus mume (Sieb.) Sieb.etZuce (FPM). The results showed that among all exposures, the treatment with FPE resulted in the significant increase (p < 0.05) of Cd and Pb concentration in shoots and roots of S. nigrum by 32.5% and 65.2% for Cd, and 38.7% and 39.6% for Pb. The biomasses of S. nigrum in all plant extract treatments were not significantly changed (p < 0.05) compared to the control (CK). The Cd and Pb extraction rates of S. nigrum in FPE treatment were increased respectively by 60.5% and 40.5% compared to CK. Though the treatment with EDTA significantly improved (p < 0.05) the concentration of Cd and Pb of S. nigrum, the Cd and Pb masses (ug plant-1) of S. nigrum did not show any significant difference compared to the CK due to the significant decrease in the shoot (20.4%) and root (22.0%) biomasses. The chelative role of FPE might be relation with its higher polyphenolic compounds. However, not sure if the contents of polyphenolic compounds was the only differences between FPE and other additives. Thus, some unknown organic matters might also play active role. This study provided valuable information on improving the phytoremediation potential of hyperaccumulator.


Assuntos
Metais Pesados/metabolismo , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Poluentes do Solo/metabolismo , Solanum nigrum/efeitos dos fármacos , Biodegradação Ambiental/efeitos dos fármacos , Biomassa , Quelantes/química , Quelantes/farmacologia , Extratos Vegetais/química , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/metabolismo , Solanum nigrum/metabolismo
9.
Ecotoxicol Environ Saf ; 220: 112410, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34126303

RESUMO

Lead (Pb) toxicity is a growing serious environmental pollution that threatens human health and crop productivity. Poplar, as an important economic and ecological forest species, has the characteristics of fasting growth and accumulating heavy metals, which is a powerful model plant for phytoremediation. Here, a novel label-free quantitative proteomic platform of SWATH-MS was applied to detect proteome changes in poplar seedling roots following Pb treatment. In total 4388 unique proteins were identified and quantified, among which 542 proteins showed significant abundance changes upon Pb(II) exposure. Functional categorizations revealed that differentially expressed proteins (DEPs) primarily distributed in specialized biological processes. Particularly, lignin and flavonoid biosynthesis pathway were strongly activated upon Pb exposure, implicating their potential roles for Pb detoxification in poplar. Furthermore, hemicellulose and pectin related cell wall proteins exhibited increased abundances, where may function as a sequestration reservoir to reduce Pb toxicity in cytoplasm. Simultaneously, up-regulation of glutathione metabolism may serve as a protective role for Pb-induced oxidative damages in poplar. Further correlation investigation revealed an extra layer of post-transcriptional regulation during Pb response in poplar. Overall, our work represents multiply potential regulators in mediating Pb tolerance in poplar, providing molecular targets and strategies for phytoremediation.


Assuntos
Chumbo/toxicidade , Metais Pesados/toxicidade , Populus/efeitos dos fármacos , Proteoma/efeitos dos fármacos , Biodegradação Ambiental , Vias Biossintéticas/efeitos dos fármacos , Chumbo/metabolismo , Metais Pesados/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Populus/metabolismo , Proteoma/metabolismo , Proteômica , Plântula/efeitos dos fármacos , Plântula/metabolismo
10.
Sci Rep ; 11(1): 9701, 2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-33958645

RESUMO

Cultivation practice using organic amendments is plausible to ensure global food security. However, plant abiotic stress due to the presence of metals and organic microcontaminants (OMCs) in fertilization products cannot be overlooked. In this study, we monitored lettuce metabolism and phenotypic response following the application of either sewage sludge (SS), the organic fraction of municipal solid waste, swine manure (SM), chemical fertilizers (CF), or no amendment (C) in a greenhouse facility. The experimental set-up consisted of five treatments with five replicates (25 experimental units randomly distributed). All fertilizers were supplied at the equivalent agronomic total nitrogen dose, but the occurrence of trace metals and/or OMCs was greater in the SS and SM than the rest. Non-target metabolomic analysis (high-resolution mass spectrometry coupled with partial least squares regression) identified more than 300 plant metabolites (amino acids, organic acids, sugar alcohols, and sugars), 55 of which showed significant changes in their relative abundances depending on the type of amendment. Functional analysis indicated that the use of CF or SS increased the levels of metabolites involved in carbohydrate and nitrogen metabolism. Therefore, although SS and SM fertilizers had a greater presence of heavy metals and/or OMCs, our results indicate that they did not induce measurable adverse effects in the lettuce phenotype or metabolism. Metabolic changes between fertilizers (CF and SS vs. C and SM) were mainly due to nitrogen availability.


Assuntos
Fertilizantes , Alface/química , Metabolômica , Contaminação de Alimentos/análise , Alface/metabolismo , Metais Pesados/metabolismo
11.
Clin Nephrol ; 96(1): 1-16, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33960297

RESUMO

Derangements of trace elements often occur in patients with renal failure and play a crucial role in chronic kidney disease. The natural history of trace element deposition with worsening chronic kidney disease has been poorly described. Some essential trace elements may get wasted (e.g., selenium, zinc, and manganese) while other trace elements accumulate (e.g., cobalt, lead, molybdenum, and vanadium). Data are most readily available relating to hemodialysis patients. Continuous renal replacement therapies (for the treatment of acute kidney injury) and chronic kidney disease patients without need for renal replacement therapy remain largely unstudied. We have synthesized all available data on mode of absorption and elimination, volume of distribution, plasma protein binding, and proteinuria to summarize the existing literature, identify future areas of research and to allow some prediction of the fate of individual trace elements in clinical scenarios where no direct observational data are available. More prospective studies evaluating the impact of abnormal trace elements and the possible therapeutic value of intervention are required to improve how robust the current international guideline recommendations (KDOQI) are with respect to trace element monitoring.


Assuntos
Metais Pesados , Insuficiência Renal Crônica , Terapia de Substituição Renal , Oligoelementos , Humanos , Metais Pesados/análise , Metais Pesados/metabolismo , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/terapia , Oligoelementos/análise , Oligoelementos/metabolismo
12.
Ecotoxicol Environ Saf ; 220: 112370, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34058673

RESUMO

A 6 weeks pot culture experiment was carried out to investigate the stabilization effects of a modified biochar (BCM) on metals in contaminated soil and the uptake of these metals by wheat seedlings. The results showed that the application of BCM significantly increased the soil fertility, the biomass of wheat seedling roots increased by more than 50%, and soil dehydrogenase (DHA) and catalase (CAT) activities increased by 369.23% and 12.61%, respectively. In addition, with the application of BCM, the diethylenetriaminepentaacetic acid extractable (DTPA-extractable) Cd, Pb, Cu and Zn in soil were reduced from 2.34 to 0.38 mg/kg, from 49.27 to 25.65 mg/kg, from 3.55 mg/kg to below the detection limit and from 4.05 to 3.55 mg/kg, respectively. Correspondingly, the uptake of these metals in wheat roots and shoots decreased by 62.43% and 79.83% for Cd, 73.21% and 66.32% for Pb, 57.98% and 68.92% for Cu, and 40.42% and 43.66% for Zn. Furthermore, BCM application decreased the abundance and alpha diversity of soil bacteria and changed the soil bacterial community structure dramatically. Overall, BCM has great potential for the remediation of metal-contaminated soils, but its long-term impact on soil metals and biota need further research.


Assuntos
Bactérias/efeitos dos fármacos , Carvão Vegetal/farmacologia , Metais Pesados/metabolismo , Plântula/metabolismo , Poluentes do Solo/metabolismo , Solo/química , Triticum/efeitos dos fármacos , Disponibilidade Biológica , Biomassa , Cádmio/metabolismo , Poluição Ambiental , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Microbiologia do Solo , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
13.
Appl Environ Microbiol ; 87(14): e0028621, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-33962982

RESUMO

Methanobactins (MBs) are small (<1,300-Da) posttranslationally modified copper-binding peptides and represent the extracellular component of a copper acquisition system in some methanotrophs. Interestingly, MBs can bind a range of metal ions, with some being reduced after binding, e.g., Cu2+ reduced to Cu+. Other metal ions, however, are bound but not reduced, e.g., K+. The source of electrons for selective metal ion reduction has been speculated to be water but never empirically shown. Here, using H218O, we show that when MBs from Methylocystis sp. strain SB2 (MB-SB2) and Methylosinus trichosporium OB3b (MB-OB3) were incubated in the presence of either Au3+, Cu2, or Ag+, 18,18O2 and free protons were released. No 18,18O2 production was observed in the presence of either MB-SB2 or MB-OB3b alone, gold alone, copper alone, or silver alone or when K+ or Mo2+ was incubated with MB-SB2. In contrast to MB-OB3b, MB-SB2 binds Fe3+ with an N2S2 coordination and will also reduce Fe3+ to Fe2+. Iron reduction was also found to be coupled to the oxidation of 2H2O and the generation of O2. MB-SB2 will also couple Hg2+, Ni2+, and Co2+ reduction to the oxidation of 2H2O and the generation of O2, but MB-OB3b will not, ostensibly as MB-OB3b binds but does not reduce these metal ions. To determine if the O2 generated during metal ion reduction by MB could be coupled to methane oxidation, 13CH4 oxidation by Methylosinus trichosporium OB3b was monitored under anoxic conditions. The results demonstrate that O2 generation from metal ion reduction by MB-OB3b can support methane oxidation. IMPORTANCE The discovery that MB will couple the oxidation of H2O to metal ion reduction and the release of O2 suggests that methanotrophs expressing MB may be able to maintain their activity under hypoxic/anoxic conditions through the "self-generation" of dioxygen required for the initial oxidation of methane to methanol. Such an ability may be an important factor in enabling methanotrophs to not only colonize the oxic-anoxic interface where methane concentrations are highest but also tolerate significant temporal fluctuations of this interface. Given that genomic surveys often show evidence of aerobic methanotrophs within anoxic zones, the ability to express MB (and thereby generate dioxygen) may be an important parameter in facilitating their ability to remove methane, a potent greenhouse gas, before it enters the atmosphere.


Assuntos
Imidazóis/metabolismo , Metais Pesados/metabolismo , Metano/metabolismo , Methylocystaceae/metabolismo , Oligopeptídeos/metabolismo , Oxigênio/química , Água/química , Metais Pesados/química , Oxirredução
14.
Arch Microbiol ; 203(7): 3893-3903, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34008070

RESUMO

Increasing environmental pollutants such as heavy metals have become one of the most severe health dangers because of rapid industrialization. Exposure to lead and nickel heavy toxic metals can lead to hazardous diseases affecting most of the organs in humans. Bioremediation is a process that uses the ability of microorganisms or plants to detoxify environmental contaminants at lower costs than physicochemical techniques. This study isolated halophilic bacteria from Khara salt lake in Iran and screened their ability to resist lead and nickel. After screening stages, three selected strains including Bacillus sp. A21, Oceanobacillus sp. A22 and Salinicoccus A43 were identified by16S rDNA sequencing and the related sequences were submitted to GeneBank with accession IDs MN588312, MN588313, and MN 588,314, respectively. These strains resist 7.2 mM, 4.1 mM, and 6.7 mM lead and 3.6 mM, 3.7 mM, and 4.1 mM nickel, respectively. Investigation of growth pattern and evaluation of bioremediation ability by atomic absorption spectroscopy revealed that Bacillus sp. A21 could decrease lead and nickel in culture medium up to 97.5% and 76%, respectively. Oceanobacillus sp. A22 showed higher lead bioremediation rate (98.8%) and lower nickel-bioremediation rate (73.5%). Salinicoccus sp. A43 showed the least bioremediation ability (92% lead and 71.7% nickel). The ability of selected strains to synthesize lead and nickel nanoparticles was evaluated using UV/Vis spectrophotometry and Energy-Dispersive X-ray Spectroscopy (EDX). Particle dimensions were measured using Scanning Electron Microscopy (SEM). Bacillus sp. A21 and Oceanobacillus sp. A22 strains were able to synthesize lead nanoparticles; however, Salinicoccus sp. A43 could synthesize both lead and nickel nanoparticles.


Assuntos
Bactérias , Biodegradação Ambiental , Metais Pesados , Nanopartículas , Bactérias/genética , Bactérias/metabolismo , Irã (Geográfico) , Lagos/microbiologia , Metais Pesados/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo
15.
J Sci Food Agric ; 101(15): 6533-6541, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34010498

RESUMO

BACKGROUND: Oilseed rape is one of the most important oilseed crops worldwide, crucial in the food and feed industries. Different environment and climatic conditions can influence its sustainable cultivation and crop yield. Aminopeptidases are crucial enzymes in many physiological processes in all organisms, including humans, so it is important to learn their behavior in food and feed sources. This study presents, for the first time, a detailed discussion on the importance of aminopeptidases, during the oilseed rape germination process, under standard and stress conditions. RESULTS: During the germination of oilseed rape under standard conditions, a significant increase in aminopeptidases activity toward N-terminal amino acids - phenylalanine (Phe), alanine (Ala), glycine (Gly), leucine (Leu), proline (Pro), methionine (Met) - was observed. The change was substrate specific, with the highest increase being observed for Gly (3.2-fold), followed by Ala (2.9-fold), Pro (2.5-fold), Met (1.5-fold), and Phe (1.3-fold). Generally, N-terminal Phe was preferentially cleaved. Germination under stress conditions, caused by several heavy metal ions (e.g. divalent copper, zinc, cadmium, and lead ions), negatively influenced the plants' growth and quality, but significantly enhanced the expression of genes encoding aminopeptidases (or potentially activated aminopeptidases precursors), which was related to the dramatic increase of their activity. CONCLUSIONS: The activity/concentration of aminopeptidases in plants is adjusted to the needs at each stage of development and stress factors occurrence. The most significant increase of activity toward N-terminal Gly and Pro proved the key role of aminopeptidases in the defense mechanisms, by supplying the plants with osmoprotectants and organic nitrogen. The results provide new concepts of oilseed rape growth and cultivation under different conditions. © 2021 Society of Chemical Industry.


Assuntos
Aminopeptidases/metabolismo , Brassica napus/enzimologia , Metais Pesados/metabolismo , Proteínas de Plantas/metabolismo , Sementes/crescimento & desenvolvimento , Aminoácidos/metabolismo , Brassica napus/crescimento & desenvolvimento , Brassica napus/metabolismo , Germinação , Sementes/enzimologia , Sementes/metabolismo
16.
Int Microbiol ; 24(3): 441-453, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33987705

RESUMO

Globally, the underlying peril of cumulative toxicity of heavy metals in water bodies contaminated by industrial effluents is a matter of great concern to the environmentalists. Heavy metals like lead, cadmium, and nickel are particularly liable for this. Such toxic water is not only hazardous to human health but also harmful to aquatic animals. Remedial measures are being taken by physico-chemical techniques, but most of them are neither eco-friendly nor cost-effective. Biological means like bioaccumulation of heavy metals by viable bacteria are often tedious. In the present study, biosorption of heavy metals is successfully expedited by surfactant exopolysaccharide (SEPS) of Ochrobactrum pseudintermedium C1 as a simple, safe, and economically sustainable option utilizing an easily available and cost-effective substrate like molasses extract. Its efficacy in bioremediation of toxic heavy metals like cadmium, nickel, and lead have been studied by UV-Vis spectrophotometry and verified by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). FTIR and zeta potential studies have also been carried out to explore this novel biosorption potential. Results are conclusive and promising. Moreover, this particular SEPS alone can remediate all these three toxic heavy metals in water. For futuristic applications, it might be a prospective and cost-effective resource for bioremediation of toxic heavy metals in aqueous environment.


Assuntos
Metais Pesados/metabolismo , Ochrobactrum/metabolismo , Polissacarídeos Bacterianos/metabolismo , Tensoativos/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Cádmio/metabolismo , Análise Custo-Benefício , Chumbo/metabolismo , Microscopia Eletrônica de Varredura , Níquel/metabolismo , Polissacarídeos Bacterianos/ultraestrutura
17.
Biomolecules ; 11(3)2021 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-33802758

RESUMO

Heavy metals (HMs) toxicity represents a global problem depending on the soil environment's geochemical forms. Biochar addition safely reduces HMs mobile forms, thus, reducing their toxicity to plants. While several studies have shown that biochar could significantly stabilize HMs in contaminated soils, the study of the relationship of soil properties to potential mechanisms still needs further clarification; hence the importance of assessing a naturally contaminated soil amended, in this case with Paulownia biochar (PB) and Bamboo biochar (BB) to fractionate Pb, Cd, Zn, and Cu using short sequential fractionation plans. The relationship of soil pH and organic matter and its effect on the redistribution of these metals were estimated. The results indicated that the acid-soluble metals decreased while the fraction bound to organic matter increased compared to untreated pots. The increase in the organic matter metal-bound was mostly at the expense of the decrease in the acid extractable and Fe/Mn bound ones. The highest application of PB increased the organically bound fraction of Pb, Cd, Zn, and Cu (62, 61, 34, and 61%, respectively), while the BB increased them (61, 49, 42, and 22%, respectively) over the control. Meanwhile, Fe/Mn oxides bound represents the large portion associated with zinc and copper. Concerning soil organic matter (SOM) and soil pH, as potential tools to reduce the risk of the target metals, a significant positive correlation was observed with acid-soluble extractable metal, while a negative correlation was obtained with organic matter-bound metal. The principal component analysis (PCA) shows that the total variance represents 89.7% for the TCPL-extractable and HMs forms and their relation to pH and SOM, which confirms the positive effect of the pH and SOM under PB and BB treatments on reducing the risk of the studied metals. The mobility and bioavailability of these metals and their geochemical forms widely varied according to pH, soil organic matter, biochar types, and application rates. As an environmentally friendly and economical material, biochar emphasizes its importance as a tool that makes the soil more suitable for safe cultivation in the short term and its long-term sustainability. This study proves that it reduces the mobility of HMs, their environmental risks and contributes to food safety. It also confirms that performing more controlled experiments, such as a pot, is a disciplined and effective way to assess the suitability of different types of biochar as soil modifications to restore HMs contaminated soil via controlling the mobilization of these minerals.


Assuntos
Carvão Vegetal/química , Fracionamento Químico/métodos , Metais Pesados/química , Solo/química , Cádmio/química , Cádmio/isolamento & purificação , Cádmio/metabolismo , Carvão Vegetal/isolamento & purificação , Cobre/química , Cobre/isolamento & purificação , Cobre/metabolismo , Poluição Ambiental , Compostos Férricos/química , Compostos Férricos/metabolismo , Concentração de Íons de Hidrogênio , Lamiales/química , Chumbo/química , Chumbo/isolamento & purificação , Chumbo/metabolismo , Compostos de Manganês/química , Compostos de Manganês/metabolismo , Metais Pesados/isolamento & purificação , Metais Pesados/metabolismo , Microscopia Eletrônica de Varredura , Compostos Orgânicos/química , Compostos Orgânicos/metabolismo , Óxidos/química , Óxidos/metabolismo , Análise de Componente Principal , Sasa/química , Espectrometria por Raios X , Zinco/química , Zinco/isolamento & purificação , Zinco/metabolismo
18.
mBio ; 12(2)2021 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-33820823

RESUMO

Gram-negative bacteria utilize the resistance-nodulation-cell division (RND) superfamily of efflux pumps to expel a variety of toxic compounds from the cell. The Escherichia coli CusA membrane protein, which recognizes and extrudes biocidal Cu(I) and Ag(I) ions, belongs to the heavy-metal efflux (HME) subfamily of RND efflux pumps. We here report four structures of the trimeric CusA heavy-metal efflux pump in the presence of Cu(I) using single-particle cryo-electron microscopy (cryo-EM). We discover that different CusA protomers within the trimer are able to bind Cu(I) ions simultaneously. Our structural data combined with molecular dynamics (MD) simulations allow us to propose a mechanism for ion transport where each CusA protomer functions independently within the trimer.IMPORTANCE The bacterial RND superfamily of efflux pumps mediate resistance to a variety of biocides, including Cu(I) and Ag(I) ions. Here we report four cryo-EM structures of the trimeric CusA pump in the presence of Cu(I). Combined with MD simulations, our data indicate that each CusA protomer within the trimer recognizes and extrudes Cu(I) independently.


Assuntos
Microscopia Crioeletrônica , Proteínas de Escherichia coli/química , Escherichia coli/metabolismo , Transporte de Íons , Proteínas de Membrana Transportadoras/química , Metais Pesados/metabolismo , Sítios de Ligação , Transporte Biológico , Cobre/metabolismo , Escherichia coli/genética , Escherichia coli/ultraestrutura , Proteínas de Escherichia coli/ultraestrutura , Proteínas de Membrana Transportadoras/ultraestrutura , Simulação de Dinâmica Molecular , Ligação Proteica , Prata/metabolismo
19.
J Chromatogr A ; 1645: 462098, 2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-33848662

RESUMO

Herein, a facile yet efficient template method to fabricate macroporous cellulose beads (MCBs) is reported. In this method, micro-size CaCO3 is utilized to create macroporous structure for fast mass transfer, and tentacle-type poly(hydroxamic acid) as adsorption ligand is immobilized on the MCBs to improve adsorption capacity. The obtained tentacle-type poly(hydroxamic acid)-modified MCMs (TP-CMCBs) show uniform spherical shape (about 80 µm), bimodal pore system (macropores≈3.0 µm; diffusional pores≈14.5 nm), and high specific surface area (52.7 m2/g). The adsorption performance of TP-CMCBs is evaluated by heavy metal ions adsorption. TP-CMCBs exhibit not only high adsorption capacities (342.5, 261.5 and 243.2 mg/g for Cu2+, Mn2+ and Ni2+, respectively.), but also fast adsorption rate (>70% of its equilibrium uptake within 30 min). Additionally, TP-CMCBs have excellent reusability, as evidenced by that the adsorption capacities have no obvious change even after five-time consecutive adsorption-desorption cycles. All results demonstrate that the proposed TP-CMCBs have great potential in removal of heavy metal ions.


Assuntos
Celulose/química , Ácidos Hidroxâmicos/química , Metais Pesados , Adsorção , Metais Pesados/análise , Metais Pesados/isolamento & purificação , Metais Pesados/metabolismo , Polímeros/química , Porosidade
20.
Arch Microbiol ; 203(6): 2761-2770, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33811263

RESUMO

Environmental health is a critical concern, continuously contaminated by physical and biological components (viz., anthropogenic activity), which adversely affect on biodiversity, ecosystems and human health. Nonetheless, environmental pollution has great impact on microbial communities, especially bacteria, which try to evolve in changing environment. For instance, during the course of adaptation, bacteria easily become resistance to antibiotics and heavy metals. Antibiotic resistance genes are now one of the most vital pollutants, provided as a source of frequent horizontal gene transfer. In this review, the environmental cause of multidrug resistance (MDR) that was supposed to be driven by either heavy metals or combination of environmental factors was essentially reviewed, especially focussed on the correlation between accumulation of heavy metals and development of MDR by bacteria. This kind of correlation was seemed to be non-significant, i.e. paradoxical. Gram-positive bacteria accumulating much of toxic heavy metal (i.e. highly stress tolerance) were unlikely to become MDR, whereas Gram-negative bacteria that often avoid accumulation of toxic heavy metal by efflux pump systems were come out to be more prone to MDR. So far, other than antibiotic contaminant, no such available data strongly support the direct influence of heavy metals in bacterial evolution of MDR; combinations of factors may drive the evolution of antibiotic resistance. Therefore, Gram-positive bacteria are most likely to be an efficient member in treatment of industrial waste water, especially in the removal of heavy metals, perhaps inducing the less chance of antibiotic resistance pollution in the environment.


Assuntos
Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Metais Pesados/toxicidade , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Humanos , Metais Pesados/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...