RESUMO
The carbonization of lignocellulosic biomass with ionic liquids (ILs) are considered as an advantageous approach for the preparation of carbonaceous materials. The commonly used imidazolium and pyridinium based ILs have drawbacks such as toxicity, resistance to biodegradation, high cost and viscosity. These issues can be mitigated by diluting ILs with water, although excessive water content above 1 wt% can reduce the solubility of biomass. This research aims to investigate the potential of pretreating wastepaper with a "fully green" ILs, amino acid-based IL with high water content, followed by pyrolysis without IL, in enhancing the properties of biochar. For this purpose, the paper was treated with an aqueous solution of IL cysteine nitrate ([Cys][NO3]), and the IL was not involved in the pyrolysis process to prevent the formation of secondary gaseous pollutants. The findings revealed that the hemicellulose and mineral filler in the paper were eliminated during pretreatment, leading to higher carbon content but lower oxygen content. As a result, the biochar exhibited micropores of 0.42 cm3g-1 and a specific surface area of 1011.21 m2 g-1. The biochar demonstrated high adsorption capacities for Cd2+, enrofloxacin, bisphenol A, ciprofloxacin, and tetracycline, with values of 45.20 mg g-1, 49.82 mg g-1, 49.90 mg g-1, 49.88 mg g-1, and 49.65 mg g-1, respectively. The proposed mechanism for the adsorption of enrofloxacin by the biochar primarily involves physical adsorption such as pore filling and electrostatic interactions, along with chemical adsorption facilitated by graphitic nitrogen.
Assuntos
Aminoácidos , Carvão Vegetal , Líquidos Iônicos , Líquidos Iônicos/química , Carvão Vegetal/química , Adsorção , Aminoácidos/químicaRESUMO
PURPOSE: Ulcerative colitis is an inflammation-related disease with a high recurrence risk. Oxysophocarpine (OSC) is a traditional Chinese medicine isolated from legumes and exerts vital functions on many human diseases. However, the OSC's role in ulcerative colitis has not been fully elucidated. This research aimed to investigate the OSC's impact on ulcerative colitis and its mechanisms. METHODS: A mouse model of ulcerative colitis was induced by dextran sulphate sodium (DSS). The effect of OSC on ulcerative colitis was examined using Disease Activity Index detection, hematoxylin-eosin (HE) staining, and enzyme-linked immunosorbent assay (ELISA). Meanwhile, the mechanism of OSC in ulcerative colitis was assessed by immunohistochemistry assay, Western blot, HE staining, and ELISA. RESULTS: For the OSC's function in ulcerative colitis, OSC increased the mice weight, decreased Disease Activity Index scores, and alleviated colitis cell infiltration and epithelial cell destruction in DSS-induced ulcerative colitis. Also, OSC mitigated oxidative stress (decreased PGE2, MPO levels, and increased SOD levels) and inflammation (decreased IL-6, TNF-α and IL-1ß levels) in DSS-induced ulcerative colitis. For the OSC's mechanism in ulcerative colitis, OSC inhibited the level of tumor necrosis factor receptor-associated Factor 6 (TRAF6) and the phosphorylation of nuclear factor-κB (NF-κB). TRAF6 overexpression abolished the effect of OSC on DSS-induced colon injury and its associated oxidative stress and inflammatory properties in ulcerative colitis. CONCLUSION: OSC decreased the TRAF6 level to reduce oxidative stress and inflammatory factors secretion in mice with DSS induced-ulcerative colitis.
Assuntos
Alcaloides , Colite Ulcerativa , Fator 6 Associado a Receptor de TNF , Animais , Humanos , Camundongos , Alcaloides/farmacologia , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/metabolismo , Colo/patologia , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Inflamação/patologia , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Estresse OxidativoRESUMO
Photothermal materials can convert renewable solar energy into thermal energy and have great potential for solar water evaporation. Copper sulfide (Cu2- x S) is an easily available and inexpensive plasmonic material with a high photothermal conversion efficiency and can be applied to solar evaporation and water purification. Monodispersed Cu7 S4 nanoparticles (NPs) and supercrystalline self-assembled superparticles are obtained via wet chemical synthesis and micelle self-assembly. The photothermal properties of the superstructures are investigated using the finite difference time domain method and laser radiation photothermography. The results show that the electromagnetic field intensity and photothermal efficiency of the self-assembly are significantly higher than those of isolated NPs, which is due to the plasmonic coupling of the NPs. The evaporation efficiency of the superstructure is significantly higher than that of isolated NPs, the metal salt ion and total organic carbon concentrations in the waterbody significantly decrease after evaporation, and the water polluted by high salt and organic dye concentrations is purified. The water quality significantly improves after the lake water from Fuxian Lake in the Yunnan-Guizhou Plateau of China is used for solar evaporation. The color changes from pale yellow to colorless and the ion and total organic carbon contents significantly decrease.
Assuntos
Energia Solar , Purificação da Água , Carbono , China , Luz Solar , Purificação da Água/métodosRESUMO
Eye movement biometrics can enable continuous verification for highly secure environments such as financial transactions and defense establishments, as well as a more personalized and tailored experience in gaze-based human-computer interactions. However, there are numerous challenges to recognizing people in real environments using eye movements, such as implicity and stimulus independence. In the instance of wayfinding, this research intends to investigate implicit and stimulus-independent eye movement biometrics in real-world situations. We collected 39 subjects' eye movement data from real-world wayfinding experiments and derived five sets of eye movement features (the basic statistical, pupillary response, fixation density, fixation semantic and saccade encoding features). We adopted a random forest and performed biometric recognition for both identification and verification scenarios. The best accuracy we obtained in the identification scenario was 78% (equal error rate, EER = 6.3%) with the 10-fold classification and 64% (EER = 12.1%) with the leave-one-route-out classification. The best accuracy we achieved in the verification scenario was 89% (EER = 9.1%). Additionally, we tested performance across the 5 feature sets and 20 time window sizes. The results showed that the verification accuracy was insensitive to the increase in the time window size. These findings are the first indication of the viability of performing implicit and stimulus-independent biometric recognition in real-world settings using wearable eye tracking.
Assuntos
Biometria , Movimentos Oculares , Tecnologia de Rastreamento Ocular , Humanos , Reconhecimento Psicológico , Movimentos SacádicosRESUMO
Citric acid (CA) can regulate the balance of anions and cations in plants, and improve their resistance to heavy metals. It is not clear if foliar application with CA has any effect on migration of Cd and Mn in rice plant. In this work, a low-Cd-accumulating indica rice line (P7) and a high-Cd-accumulating line (HZ) were used to investigate the influence of CA on the transport of Cd and Mn as well as amino acid metabolism in grains. Content of Cd in grains and other organs increased with the increase of Cd content (0.1-2.4 mg kg-1) in soil, while decreased with the foliar application with CA. With the increase of Cd content in rice grains, the content of most amino acids in HZ, P7, HZ+CA and P7 + CA showed an obvious decline trend. Foliar application with CA efficiently raised the Mn:Cd ratio in grains and nodes of both HZ and P7. Meanwhile, the expression levels of OsNramp2, 3 and 5 in panicles were efficiently enhanced by CA application when plants grew in soil with Cd content of 0.6-2.4 mg kg-1. The increasing effect of CA on the content of 4 amino acids (i.e., Glu, Phe, Thr and Ala) in grains was related to varieties and Cd pollution. These results indicate that foliar application with CA can regulate the transport of Cd and Mn in the opposite directions in tissues and inhibit Cd accumulation in grains by enhancing expression of OsNRAMP 2, 3 or 5 and triggering the defense response of some amino acids in Cd-contaminated environment.
Assuntos
Aminoácidos/metabolismo , Cádmio/metabolismo , Ácido Cítrico/farmacologia , Grão Comestível/fisiologia , Manganês/metabolismo , Substâncias Protetoras/farmacologia , Transporte Biológico , Poluição Ambiental , Metais Pesados/análise , Oryza/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Solo/química , Poluentes do Solo/análiseRESUMO
Non-selective cation channels (NSCCs) play important roles in uptake of heavy metals in plants. However, little information is available concerning the contribution of NSCCs to cadmium (Cd) transport in rice seedlings. Results from the hydroponic experiment showed that the inhibition of 2.7 µM Cd on the development of rice roots was alleviated by adding 0.1â¯mM gadolinium (Gd) in nutrient solution, companied by reduction of Cd content by 55.3% in roots and by 45.0% in shoots. Inhibition of Gd on Cd accumulation in cytoplasm fraction (F3) was much greater than that in cell walls (F1) and organelles (F2) in roots. After increasing concentrations of Mn and Zn in nutrient solution, adding 0.1â¯mMâ¯Gd resulted in reductions in Cd content by 89.1%, in micronutrients by 54.9% and in macronutrients by 5.4% in roots, respectively. Cd stress resulted in significant increase of PC2â¼4 and free amino acids, but decrease of V-ATPase activity by 32.3% in roots. These results indicate that NSCCs make a great contribution to uptake of Cd in rice seedlings and opportunities for Cd to be transported by NSCCs can be efficiently reduced by blocking NSCCs and/or increasing essential microelements like Mn and Zn.
Assuntos
Cádmio/metabolismo , Gadolínio/farmacologia , Canais Iônicos/antagonistas & inibidores , Transporte de Íons/efeitos dos fármacos , Oryza/metabolismo , Plântula/metabolismo , Hidroponia , Oryza/efeitos dos fármacos , Oryza/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimentoRESUMO
Altering Cd chemical form is one of the mechanisms to alleviate Cd toxicity in rice plant. Field experiments were carried out in this study to investigate the potential of rice vegetative organs in altering Cd into insoluble chemical forms in the natural environment. Experimental results showed that more than 80% of Cd in rice roots existed in the insoluble forms. Uppermost nodes altered Cd into insoluble form preferentially and generally had higher content of insoluble Cd than other organs. Rachises displayed a slow increasing trend in soluble Cd when total Cd in roots was less than 1.8â¯mgâ¯kg-1. However, when Cd content in roots exceeded 2.8â¯mgâ¯kg-1, the ratio of insoluble to soluble Cd remained stable at 85:15 in rachises and roots, and at 75:25 in uppermost nodes and flag leaves. Cd concentration in grains was greatly lower than that in vegetative organs, and closely correlated with the content of soluble Cd in rachises (r = 0.991**) as well as in uppermost nodes. Soluble Cd in the uppermost nodes displayed a much lower mobility than that in other organs. Accumulation of soluble Cd was always companied by decrease of Ca and increase of Mn in roots, uppermost nodes and rachises. A small increase of soluble Cd from 0.05 to 0.1 mg kg-1 caused a sharp decline of Ca:Mn ratio in roots and rachises. Roots and nodes had much higher Ca:Mn ratio than rachises when soluble Cd was less than 0.5â¯mgâ¯kg-1 in them. These results indicate that vegetative organs have a great potential to alter more than 75% Cd into insoluble forms and increasing Ca:Mn ratio may be another way to alleviate Cd toxicity by establishing new ionic homeostasis in rice plants.
Assuntos
Cádmio/toxicidade , Cálcio/análise , Manganês/análise , Oryza/efeitos dos fármacos , Cádmio/química , Grão Comestível/química , Grão Comestível/efeitos dos fármacos , Modelos Teóricos , Oryza/química , Folhas de Planta/química , Folhas de Planta/efeitos dos fármacos , Raízes de Plantas/química , Raízes de Plantas/efeitos dos fármacos , SolubilidadeRESUMO
Copper sulfides (Cu2-x S), are a novel kind of photothermal material exhibiting significant photothermal conversion efficiency, making them very attractive in various energy conversion related devices. Preparing high quality uniform Cu2-x S nanocrystals (NCs) is a top priority for further energy-and sustainability relevant nanodevices. Here, a shape-controlled high quality Cu7 S4 NCs synthesis strategy is reported using sulfur in 1-octadecene as precursor by varying the heating temperature, as well as its forming mechanism. The performance of the Cu7 S4 NCs is further explored for light-driven water evaporation without the need of heating the bulk liquid to the boiling point, and the results suggest that as-synthesized highly monodisperse NCs perform higher evaporation rate than polydisperse NCs under the identical morphology. Furthermore, disk-like NCs exhibit higher water evaporation rate than spherical NCs. The water evaporation rate can be further enhanced by assembling the organic phase Cu7 S4 NCs into a dense film on the aqueous solution surface. The maximum photothermal conversion efficiency is as high as 77.1%.
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Catalytic wet peroxide oxidation (CWPO) of phenol over clay-based catalysts in the presence and absence of NaCl was investigated. Changes in the H2O2, Cl(-), and dissolved metal ion concentration, as well as solution pH during phenol oxidation, were also studied. Additionally, the intermediates formed during phenol oxidation were detected by liquid chromatography-mass spectroscopy and the chemical bonding information of the catalyst surfaces was analyzed by X-ray photoelectron spectroscopy (XPS). The results showed that the presence of Cl(-) increased the oxidation rate of phenol to 155%, and this phenomenon was ubiquitous during the oxidation of phenolic compounds by H2O2 over clay-based catalysts. Cl(-)-assisted oxidation of phenol was evidenced by several analytical techniques such as mass spectroscopy (MS) and XPS, and it was hypothesized that the rate-limiting step was accelerated in the presence of Cl(-). Based on the results of this study, the CWPO technology appears to be promising for applications in actual saline phenolic wastewater treatment.
Assuntos
Silicatos de Alumínio/química , Cloretos/química , Peróxido de Hidrogênio/química , Fenol/química , Águas Residuárias/química , Catálise , Argila , Oxirredução , Poluentes Químicos da ÁguaRESUMO
The distributions of heavy metals in paddy fields and rice along river valleys were studied to explore the key factors affecting the accumulation of heavy metals in the upstream terraces and downstream plains. Results from 975 sampling sites showed that elevation, growing season and soil organic matter (OM) had significant effects on the content of Cd and Pb in topsoil and rice. The content of Cd (0.47-0.66 mg kg-1) and Pb (49.9-68.6 mg kg-1) in paddy fields with low elevation (30-60 m) in the downstream plains was significantly higher than the content of Cd (0.29-0.38 mg kg-1) and Pb (43.9-56.3 mg kg-1) in the upstream terraces with high altitude (60-90 m). In the double-rice production area, late rice generally produced grains with higher Cd and Pb content than early rice. Soil Cd was positively increased with the content of OM, especially in the downstream plains. When elevation was used for principal component analysis, plains with low elevation were grouped together with high content of total and soluble Cd, OM and Pb in soil, as well as high content of Cd and Pb in late rice. Altitude is one of the key factors affecting Cd content in rice. Although content of Cr (93.7-138.0 mg kg-1) was significantly higher than that of Cd and Pb in soil, content of Cr was lower than that of Cd in rice. These results indicate that paddy fields with elevation of 30-60 m in the downstream plains had high risk to produce late rice with Cd and Pb content exceeding the food safety standard 0.2 mg kg-1, which may be resulted from the driving force of runoff on soil soluble Cd and Pb from terraces to alluvial plains in river valleys.
RESUMO
A field experiment with double cropping rice was carried out to study the foliar application effects of dicarboxylicdimethylammonium chloride (DDAC) on cadmium (Cd) and arsenic (As) accumulation in rice grains. The results showed that the spraying of DDAC could significantly reduce the accumulation of Cd and As in rice grains. The highest reductions in Cd and As content were observed when 1.5 mmol L-1 DDAC was sprayed, with 49.1% and 27.4% reductions in Cd and As content in early rice grains and 56.5% and 28.1% reductions in Cd and As content in late rice grains, respectively. In addition, the content of calcium (Ca) in rice grains increased significantly after DDAC foliar application, which was also conducive to the synthesis of amino acids such as glutamate (Glu), glycine (Gly) and cysteine (Cys) in rice grains. The results indicated that the foliar spraying of DDAC can inhibit the absorption, transport, accumulation and toxicity of Cd and As in rice grains by increasing amino acid synthesis and regulating the absorption and transport of essential elements.
RESUMO
Malic acid (MA) plays an important role in plant tolerance to toxic metals, but its effect in restricting the transport of harmful metals remains unclear. In this study, japonica rice NPB and its fragile-culm mutant fc8 with low cellulose and thin cell wall were used to investigate the influence of MA on the accumulation of 4 toxic elements (Cd, Pb, Ni, and Cr) and 8 essential elements (K, Mg, Ca, Fe, Mn, Zn, Cu and Mo) in rice. The results showed that fc8 accumulated less toxic elements but more Ca and glutamate in grains and vegetative organs than NPB. After foliar application with MA at rice anthesis stage, the content of Cd, Pb, Ni significantly decreased by 27.9-41.0%, while those of Ca and glutamate significantly increased in both NPB and fc8. Therefore, the ratios between Cd and Ca in grains of NPB (3.4) and fc8 (1.5) were greatly higher than that in grains of NPB + MA (1.1) and fc8+MA (0.8) treatments. Meanwhile, the expression of OsCEAS4,7,8,9 for the cellulose synthesis in secondary cell walls were down-regulated and cellulose content in vegetative organs of NPB and fc8 decreased by 16.7-21.1%. However, MA application significantly up-regulated the expression of GLR genes (OsGLR3.1-3.5) and raised the activity of glutamic-oxalacetic transaminease for glutamate synthesis in NPB and fc8. These results indicate that hazard risks of toxic elements in foods can be efficiently reduced through regulating cellulose biosynthesis and GLR channels in plant by combining genetic modification in vivo and malic acid application in vitro.
Assuntos
Metais Pesados , Oryza , Poluentes do Solo , Cádmio/análise , Cromo/metabolismo , Níquel/toxicidade , Níquel/metabolismo , Oryza/genética , Oryza/metabolismo , Regulação para Cima , Regulação para Baixo , Chumbo/metabolismo , Glutamatos/genética , Glutamatos/metabolismo , Celulose/metabolismo , Poluentes do Solo/análise , Solo , Metais Pesados/análiseRESUMO
Excessive cadmium (Cd) in rice is a global environmental problem. Therefore, reducing Cd content in rice is of great significance for ensuring food security and human health. A field experiment was conducted to study the effects of foliar application of citric acid (CA) on Cd absorption and transportation in rice under high Cd-contaminated soils (2.04 mg·kg-1). This study revealed that there was a negative correlation between Cd content in vegetative organs and CA content, and that foliar spraying of CA (1 mM and 5 mM) significantly increased CA content and reduced Cd content in vegetative organs. The Cd reduction effect of 5 mM CA was better than that of 1 mM, and 5 mM CA reduced Cd content in grains and spikes by 52% and 37%, respectively. CA significantly increased Mn content in vegetative organs and increased Ca/Mn ratios in spikes, flag leaves, and roots. CA significantly reduced soluble Cd content in vegetative organs and promoted the transformation of Cd into insoluble Cd, thus inhibiting the transport of Cd from vegetative organs to grains. The foliar field application of 1 mM and 5 mM CA could inhibit Cd absorption and transportation by reducing Cd bioactivity and increasing the antagonistic of essential elements in rice vegetative organs. These results provide technical support and a theoretical basis for solving the problem of excessive Cd in rice.
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The mechanism of carboxymethylammonium chloride (CC) regulating cadmium (Cd) accumulation in rice was studied in field and hydroponic experiments. Field experiments showed that 0.2-1.2 mmol L-1 CC spraying effectively reduced Cd accumulation by 44 %-77 % in early rice grains and 39 %-78 % in late rice grains, significantly increased calcium (Ca) content and amino acids content in grains, as well as alleviated Cd-induced oxidative damage in leaves. Hydroponic experiments further verified the inhibition effect of CC on Cd accumulation. 1.2 mmol L-1 CC made the highest decrease of Cd content in shoots and roots of hydroponic seedlings by 45 % and 53 %, respectively. Exogenous CC significantly increased glutamate (Glu), glycine (Gly) and glutathione (GSH) content, and improved the activities of catalase (CAT) and superoxide dismutase (SOD) by 41-131 % and 11-121 % in shoots of hydroponic seedlings, respectively. Exogenous CC also increased the relative expression of OsGLR3.1-3.5 in the shoots and roots of hydroponic seedlings. The quantum computational chemistry was used to clarify that the Gly radical provided by CC could form various complexes with Cd through carboxyl oxygen atoms. These results showed that exogenous application of CC improved the tolerance to Cd by enhancing the antioxidant capacity; inhibited the absorption, transport and accumulation of Cd in rice by (1) promoting chelation, (2) increasing the GLRs activity through upregulating the content of Glu, Gly, as well as the expression of OsGLR3.1-3.5.
Assuntos
Cádmio , Oryza , Oryza/metabolismo , Oryza/genética , Cádmio/metabolismo , Poluentes do Solo/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Regulação da Expressão Gênica de PlantasRESUMO
Microorganisms play an important role in heavy metal bioremediation and soil fertility. The effects of soil inoculation with Pseudomonas sp. W112 on Cd accumulation in wheat were investigated by analyzing the transport, subcellular distribution and speciation of Cd in the soil and plants. Pseudomonas sp. W112 application significantly decreased Cd content in the roots, internode and grains by 10.2%, 29.5% and 33.0%, respectively, and decreased Cd transfer from the basal nodes to internodes by 63.5%. Treatment with strain W112 decreased the inorganic and water-soluble Cd content in the roots and increased the proportion of residual Cd in both the roots and basal nodes. At the subcellular level, the Cd content in the root cell wall and basal node cytosol increased by 19.6% and 61.8%, respectively, indicating that strain W112 improved the ability of the root cell wall and basal node cytosol to fix Cd. In the rhizosphere soil, strain W112 effectively colonized and significantly decreased the exchangeable Cd, carbonate-bound Cd and iron-manganese oxide-bound Cd content by 43.5%, 27.3% and 17.6%, respectively, while it increased the proportion of residual Cd by up to 65.2%. Moreover, a 3.1% and 23.5% increase in the pH and inorganic nitrogen content in the rhizosphere soil, respectively, was recorded. Similarly, soil bacterial community sequencing revealed that inoculating with strain W112 increased the abundance of Pseudomonas, Thauera and Azoarcus, which are associated with inorganic nitrogen metabolism, and decreased that of Acidobacteria, which is indicative of soil alkalinization. Hence, root application of Pseudomonas sp. W112 improved soil nitrogen availability and inhibited Cd accumulation in the wheat grains in a two-stage process: by reducing the Cd availability in the rhizosphere soil and by improving Cd interception and fixation in the wheat roots and basal nodes. Pseudomonas sp. W112 may be a suitable bioremediation agent for restoring Cd-contaminated wheat fields.
Assuntos
Cádmio , Poluentes do Solo , Cádmio/análise , Triticum/metabolismo , Solo/química , Disponibilidade Biológica , Pseudomonas/metabolismo , Poluentes do Solo/análise , Raízes de Plantas/metabolismo , Nitrogênio/análiseRESUMO
In order to evaluate the feasibility of using Burkholderia sp. Y4 as a cadmium ï¼Cdï¼-reducing bacterial agent in contaminated wheat fieldsï¼ the changes in the rhizosphere soil microbial community and Cd available stateï¼ as well as the content and transport characteristics of Cd in the wheat rootï¼ basal nodeï¼ internodeï¼ and grain under the treatment of strain Y4 were tested using microbial high-throughput sequencingï¼ step-by-step extractionï¼ subcellular distributionï¼ and occurrence analyses. The results showed that root application of strain Y4 significantly reduced the root and grain Cd content of wheat by 7.7% and 30.3%ï¼ respectivelyï¼ compared with that in the control treatment. The Cd content and Cd transfer factor results in wheat vegetative organs showed that strain Y4 reduced the Cd transfer factor from basal node to internode by 79.3%ï¼ and Cd content in the wheat internode stem also decreased by 50.9%. The study of Cd occurrence morphology showed that strain Y4 treatment increased the proportion of residual Cd in roots and basal gangliaï¼ decreased the contents of inorganic and water-soluble Cd in rootsï¼ and increased the content of residual Cd in basal ganglia. Further examination of the subcellular distribution of Cd showed that the Cd content in root cell walls and basal ganglia cell fluid increased by 21.3% and 98.2%ï¼ respectivelyï¼ indicating that the Cd fixation ability of root cell walls and basal ganglia cell fluid was improved by the strain Y4 treatment. In the rhizosphere soilï¼ it was found that the microbial community structure was changed by strain Y4 application. Under the Y4 treatmentï¼ the relative abundance of Burkholderia increased from 9.6% to 11.5%ï¼ whereas that of Acidobacteriota decreased. Additionallyï¼ the relative abundance of Gemmatimonadalesï¼ Pseudomonadalesï¼ and Chitinophagales were also increased by strain Y4 treatment. At the same timeï¼ the application of strain Y4 increased the pH value of rhizosphere soil by 8.3%. The contents of exchangeable Cdï¼ carbonate-bound Cdï¼ and iron-manganese oxide-bound Cd in the soil decreased by 44.4%ï¼ 21.7%ï¼ and 15.9%ï¼ respectivelyï¼ whereas the proportion of residual Cd reached 53.6%. Root application of strain Y4 increased the contents of nitrate nitrogen and ammonium nitrogen in the soil by 22.0% and 21.4%ï¼ respectivelyï¼ and the contents of alkaline nitrogen also increased to a certain extent. In conclusionï¼ the root application of strain Y4 not only improved soil nitrogen availability but also inhibited Cd transport and accumulation from contaminated soil to wheat grains in a "two-stage" manner by reducing Cd availability in rhizosphere soil and improving Cd interception and fixation capacity of wheat roots and basal nodes. Thereforeï¼ Burkholderia Y4 has application potential as a Cd-reducing and growth-promoting agent in wheat.
Assuntos
Burkholderia , Compostos Férricos , Poluentes do Solo , Cádmio/análise , Triticum , Burkholderia/fisiologia , Fator de Transferência , Solo/química , Nitrogênio/análise , Poluentes do Solo/análiseRESUMO
To explore the effect of exogenous application of chlorinated amino acetic acid on cadmium (Cd) transport characteristics in rice seedlings, X24 and Z35 rice were taken as the research objects to carry out hydroponics experiments, and the changes of Cd content in rice seedlings, rice mineral elements and amino acid content in rice were analyzed. The results showed that exogenous application of 1.2 mmol·L-1 chlorinated amino acetic acid inhibited cadmium in shoots and roots of rice seedlings; Cd content in shoots and roots were reduced by up to 62.19% and 45.61%, respectively. The majority of cadmium was in the cell wall of shoots and roots; this decreased with the increase of the concentration of chlorinated acetic acid. In addition, the Mn content in shoots and Ca content in roots of rice seedlings increased significantly after the application of chlorinated amino acetic acid. The results of amino acid analysis showed that the contents of aspartic acid, glutamic acid and cystine in rice seedlings were increased. These results indicate that exogenous application of chlorinated amino acetic acid is beneficial to the synthesis of aspartic acid, glutamic acid and cysteine in rice seedlings, increases the content of Mn in shoots and Ca in roots of rice seedlings, and significantly alleviates cadmium stress in seedlings. This provides a theoretical basis for the development of an environmentally friendly Cd-lowering foliar fertilizer for rice.
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The mechanism of reactive oxygen species (ROS) burst in rice cells induced by cadmium (Cd) stress remains poorly understood. The present study shows that the burst of superoxide anions (O2·-) and hydrogen peroxide (H2O2) in roots and shoots led by Cd stress was attributed to the disturbance of citrate (CA) valve and the damage of antioxidant enzyme structure in the rice seedlings. Cd accumulation in cells altered the molecular structure of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) through attacking glutamate (Glu) and other residues, leading to the significant reduction of their activities in clearing O2·- and decomposing H2O2. Citrate supplementation obviously increased the activity of antioxidant enzymes and decreased â¼20-30% of O2·- and H2O2 contents in roots and shoots. Meanwhile, the synthesis of metabolites/ligands such as CA, α-ketoglutarate (α-KG) and Glu as well as the activities of related enzymes in CA valve were remarkably improved. The activities of antioxidant enzymes were protected by CA through forming stable hydrogen-bonds between CA and antioxidant enzymes, and forming the stable chelates between ligands and Cd. These findings indicate that exogenous CA mitigated the toxicity of ROS under Cd stress by the ways of restoring CA valve function to reduce the production of ROS, and improving the stability of enzyme structure to enhance antioxidant enzymes activity.
Assuntos
Antioxidantes , Oryza , Antioxidantes/farmacologia , Espécies Reativas de Oxigênio , Cádmio/toxicidade , Ácido Cítrico/farmacologia , Peróxido de Hidrogênio , Ligantes , Catalase , Superóxido Dismutase , Plântula , Raízes de PlantasRESUMO
Solid-state nanopores/nanochannels, with their high stability, tunable geometry, and controllable surface chemistry, have recently become an important tool for constructing biosensors. Compared with traditional biosensors, biosensors constructed with solid-state nanopores/nanochannels exhibit significant advantages of high sensitivity, high specificity, and high spatiotemporal resolution in the detection single entities (such as single molecules, single particles, and single cells) due to their unique nanoconfined space-induced target enrichment effect. Generally, the solid-state nanopore/nanochannel modification method is the inner wall modification, and the detection principles are the resistive pulse method and the steady-state ion current method. During the detection process, solid-state nanopore/nanochannel is easily blocked by single entities, and interfering substances easily enter the solid-state nanopore/nanochannel to generate interference signals, resulting in inaccurate measurement results. In addition, the problem of low flux in the detection process of solid-state nanopore/nanochannel, these defects limit the application of solid-state nanopore/nanochannel. In this review, we introduce the preparation and functionalization of solid-state nanopore/nanochannel, the research progress in the field of single entities sensing, and the novel sensing strategies on solving the above problems in solid-state nanopore/nanochannel single-entity sensing. At the same time, the challenges and prospects of solid-state nanopore/nanochannel for single-entity electrochemical sensing are also discussed.
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Técnicas Biossensoriais , Nanoporos , Técnicas Biossensoriais/métodos , NanotecnologiaRESUMO
Perovskites with nano-flexible texture structures and excellent catalytic properties have attracted considerable attention for persulfate activation in addressing the organic pollutants in water. In this study, highly crystalline nano-sized LaFeO3 was synthesized by a non-aqueous benzyl alcohol (BA) route. Under optimal conditions, an 83.9% tetracycline (TC) degradation and 54.3% mineralization were achieved at 120 min by using a coupled persulfate/photocatalytic process. Especially compared to LaFeO3-CA (synthesized by a citric acid complexation route), the pseudo-first-order reaction rate constant increased by 1.8 times. We attribute this good degradation performance to the highly specific surface area and small crystallite size of the obtained materials. In this study, we also investigated the effects of some key reaction parameters. Then, the catalyst stability and toxicity tests were also discussed. The surface sulfate radicals were identified as the major reactive species during the oxidation process. This study provided a new insight into nano-constructing a novel perovskite catalyst for the removal of tetracycline in water.