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•The intestinal toxicity of MPs with different length on zebrafish was investigated through metabolomics.•MPs can be taken up by zebrafish at different developmental stages, ...especially in the early life stage.•MPs were observed in zebrafish gut, causing length-dependent intestinal damage and toxicities.•Long MPs induced more serious effects, such as the dramatically derease of the food intake, etc.•Microplastic fibers up-regulated glycerophospholipids metabolism and down-regulated fatty acyls metabolism.
To explore the intestinal toxicity of microplastic fibers, zebrafish larvae and adults were exposed to different length of microplastic fibers (50 ± 26 μm and 200 ± 90 μm). After exposure, microplastic fibers were observed in the gut of zebrafish even at the early life stage, causing length-dependent intestinal damage and toxicities manifested by histopathological changes and biomarker responses. Long microplastic fibers induced more serious effects. They significantly decreased the food intake of zebrafish by 54 %–67 % compared with short microplastic fibers. Metabolomics was conducted to further reveal the metabolic alterations induced by microplastic fibers in zebrafish. A total of 124 and 123 metabolites were significantly changed by short and long microplastic fibers. At the meanwhile, 41 significantly changed metabolites were shared between short and long fibers treatment groups and were further investigated to reveal the influence of fiber length on the toxicity. The results demonstrate that microplastic fibers can up-regulate glycerophospholipids metabolism which exacerbates oxidative damage and inflammation and down-regulate fatty acyls metabolism related to nutritional deficiency. These novel findings enhance our understanding of the intestinal toxicity of microplastic fibers and demonstrate that metabolomics is powerful to unravel the underlying mechanisms of microplastics (MPs) toxicity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Microplastics have become emerging contaminants, causing widespread concern about their potential toxic effects. In this study, the uptake and tissue accumulation of polystyrene microplastics ...(PS-MPs) in zebrafish were detected, and the toxic effects in liver were investigated. The results showed that after 7 days of exposure, 5 μm diameter MPs accumulated in fish gills, liver, and gut, while 20 μm diameter MPs accumulated only in fish gills and gut. Histopathological analysis showed that both 5 μm and 70 nm PS-MPs caused inflammation and lipid accumulation in fish liver. PS-MPs also induced significantly increased activities of superoxide dismutase and catalase, indicating that oxidative stress was induced after treatment with MPs. In addition, metabolomic analysis suggested that exposure to MPs induced alterations of metabolic profiles in fish liver and disturbed the lipid and energy metabolism. These findings provide new insights into the toxic effects of MPs on fish.
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IJS, KILJ, NUK, PNG, UL, UM
The adsorption of tetracycline (TC) on a Na-montmorillonite was studied as a function of five background electrolyte cations (Li+, Na+, K+, Mg2+ and Ca2+), one transitional metal cation (Cu2+) and ...humic acid (HA) over a pH range from 3 to 9 using batch experiments combined with XRD and FTIR measurement. Results showed that pH had great effect on the TC adsorption and acidic condition is more favored. Monovalent (Li+, Na+ and K+) and divalent (Mg2+, Ca2+ and Cu2+) cations showed very different effects on the TC adsorption onto montmorillonite. In the presence of monovalent cations, the adsorption edge curves were little affected by the types of cations. They presented a great decrease at pH<6, then an increase to a local maximum at about pH 8, followed by a gradual decrease (8<pH<9), which might resulted from cation exchange at the interlayer surface sites and surface complexation at the basal or edge sites. In the presence of divalent cations, the adsorption of TC was enhanced compared to the ones in the presence of monovalent cations, indicating other mechanism might involve. The enhanced TC adsorption has an order: Cu2+≫Ca2+>Mg2+, which might be due to the capability of “bridge” effect of divalent cations. The difference of enhancing TC adsorption in the presence of Ca2+ and Mg2+ might be a result of different ionic radii and different interacting groups in TC molecular. XRD results showed that TC was intercalated into interlayers of montmorillonite since the interlayer expansion was observed. The band changes of amide carbonyl and amino groups in tricarbonyl methane group and the carbonyl group in phenolic deketone group in the FTIR spectra of TC equilibrated with montmorillonite confirmed that TC was adsorbed to the clay via cation exchange and surface complexation. It was also found that the effect of HA on the TC adsorption was pH-dependent and the presence of HA significantly reduced the mobility of TC in solution especially under acidic condition due to the complexation between cationic or zwitterionic TC species and the deprotonated sites on HA (mainly carboxylic groups) via electrostatic attraction. These results suggested that coexistence of divalent cations and HA would reduce TC's mobility in soil environment, especially at acidic condition.
► Tetracycline adsorption to montmorillonite by ion exchange and surface complexation. ► Divalent cations improved adsorption via ion bridging: Cu2+≫Ca2+>Mg2+. ► Humic acid reduced the mobility of tetracycline in solution under acidic condition. ► Cations and humic acid have great effects on tetracycline mobility in soils.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Tetracycline (TC), a common antibiotic, can behave as an efficient ligand with cations, but the effect of its interaction with heavy metal cations on the mobility of both species in soils has not ...been well evaluated. In this study, the complexation affinities of TC with Cd (II), Cu (II) and Pb (II) were examined using potentiometric titration and spectroscopic methods. The cosorption behavior of TC and metal ions onto three selected Chinese soils was evaluated using batch adsorption experiments. The presence of metal cations promoted TC adsorption through an ion bridging effect in the order Cu (II) > Pb (II) > Cd (II), which is in accordance with their complexation ability with TC. The addition of TC affects metal adsorption differently depending on the solution pH and metal type. Therefore, it is necessary to consider the complexation ability of TC and divalent metal cations when evaluating their mobility in soils.
•The complex affinity with TC has an order of Cu(II) > Pb(II) > Cd(II).•The complexation constants of TC with the three metals are obtained.•The cosorption behavior in soils greatly depends on the complexation affinity.
The interaction between tetracycline and metal cations can influence the adsorption behavior of these species in soils, depending on their complexation ability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this study, the toxic effects of clorpyrifos (CPF) on the gut microbiome and related urine metabolome in mouse (Mus musculus) were investigated. Mice were exposed to a daily dose of 1 mg kg−1 ...bodyweight of CPF for 30 d. As a result, CPF significantly altered the gut microbiota composition in terms of the relative abundance of key microbes. Meanwhile, CPF exposure induced the alterations of urine metabolites related to the metabolism of amino acids, energy, short-chain fatty acids (SCFAs), phenyl derivatives and bile acids. High correlations were observed between perturbed gut microbiome and altered metabolic profiles. These perturbations finally resulted in intestinal inflammation and abnormal intestinal permeability, which were also confirm by the histologic changes in colon and remarkable increase of lipopolysaccharide (LPS) and diamine oxidase (DAO) in the serum of CPF-treated mice. Our findings will provide a new perspective to reveal the mechanism of CPF toxicity.
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•Toxic effects of CPF on mice gut microbiome and urine metabolome were investigated.•CPF changed the gut microbiota composition and metabolism related genes expression.•Some gut microbiota-related metabolites were perturbed by CPF exposure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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In this study, a charge distribution multisite surface complexation model (CD–MUSIC) for adsorption of chromate onto goethite was carefully developed. The adsorption of Cr(VI) on ...goethite was firstly investigated as a function of pH, ionic strength and Cr(VI) concentration. Results showed that an inner-sphere complexation mechanism was involved because the retention of Cr(VI) was little influenced by ionic strength. Then two surface species: a bidentate complex (Fe2O2CrOOH) and a monodentate complex (FeOCrO3−3/2), which is constrained by prior spectroscopic evidence were proposed to fit the macroscopic adsorption data. Modeling results showed that the bidentate complex was found to be the dominant species at low pH, whereas, with increasing pH, monodentate species became more pronounced. The model was then verified by prediction of competitive adsorption of chromate and phosphate at various ratios and ionic strengths. The model successfully predicted the inhibition of chromate with the presence of phosphate, suggesting phosphate has higher affinity to goethite surface than Cr(VI). Results showed that the model developed in this study for Cr(VI) onto goethite was applicable for various conditions. It is a useful supplement for the surface complexation model database for oxyanions onto goethite surfaces.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Cd and Zn pollution was observed to often occur simultaneously in soils. However, previous studies focused on single heavy metal instead of Cd and Zn combined pollution. Castor (Ricinus communis) is ...considered to have great potential for contaminated soil remediation. The resistance of castor seedlings to heavy metals and the mechanism behind it remain unknown. In this study, the tolerance and accumulation ability of castor seedlings to Cd and Zn were investigated, and the accumulation mechanism involving the subcellular distribution in different tissues was further explored. The results on biomass and chlorophyll revealed that castor seedlings have good tolerance to the pollution with 0–5 mg/kg Cd and 380 mg/kg Zn, while not to the heavy pollution with 25 mg/kg Cd and 380 mg/kg Zn. The maximum accumulation concentrations of Cd and Zn, 175.3 mg Cd/kg and 386.8 mg/kg Zn, appeared in castor seedling root instead of stem and leaf, indicating that root played a significant part in accumulating Zn and Cd. The relative low dosage of Cd (0–5 mg/kg) promoted the accumulation of Zn in the subcellular component, while high dosage (25 mg/kg) inhibited the accumulation of Zn. In subcellular accumulation and distribution of castor seedlings, Cd (27.1%–69.4%) and Zn (39.6%–66.6%) in the cell wall was the highest. With the increase of Cd addition, the accumulation of Cd increased in cell wall while decreased in organelle and soluble fraction. Hydroxyl, amino, amides and carboxyl functional groups on cell wall might provided the main binding sites for Cd and Zn.
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•Tolerance of castor seedlings to Cd–Zn and their accumulation were studied for the first time.•Castor seedlings were deduced to have better tolerance to Cd and Zn than mature castors.•Cd and Zn mainly accumulated in root of castor seedlings.•Cd (51%–69%) and Zn (40%–62%) mainly accumulated in the cell wall of the root.•A synergistic and antagonistic accumulation effect existed in the co-presence of Cd and Zn.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Copper (II) significantly enhanced tetracycline adsorption via acting as a bridge ion to form goethite–Cu2+–tetracycline complex because Cu2+ could form strong and specific inner-sphere surface ...complexes. Display omitted
► Background electrolyte cations showed almost no effect on tetracycline adsorption onto goethite. ► Copper (II) and humic acid enhanced the adsorption to different extent. ► Tetracycline was adsorbed by goethite through inner-sphere complextion. ► Copper (II) and humic acid have great effects on tetracycline mobility in soils.
Adsorption of tetracycline, one of the most widely used antibiotics, onto goethite was studied as a function of pH, metal cations, and humic acid (HA) over a pH range 3–10. Five background electrolyte cations (Li+, Na+, K+, Ca2+, and Mg2+) with a concentration of 0.01M showed little effect on the tetracycline adsorption at the studied pH range. While the divalent heavy metal cation, Cu2+, could significantly enhance the adsorption and higher concentration of Cu2+, stronger adsorption was found. The results indicated that different adsorption mechanisms might be involved for the two types of cations. Background electrolyte cations hardly interfere with the interaction between tetracycline and goethite surfaces because they only form weak outer-sphere surface complexes. On the contrary, Cu2+ could enhance the adsorption via acting as a bridge ion to form goethite–Cu2+–tetracycline surface complex because Cu2+ could form strong and specific inner-sphere surface complexes. HA showed different effect on the tetracycline sorption under different pH condition. The presence of HA increased tetracycline sorption dramatically under acidic condition. Results indicated that heavy metal cations and soil organic matters have great effects on the tetracycline mobility in the soil environment and eventually affect its exposure concentration and toxicity to organisms.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Flavonoids are potential strikingly natural compounds with antioxidant activity and acetylcholinesterase (AChE) inhibitory activity for treating Alzheimer’s disease (AD). In present study, in line ...with our interests in flavonoid derivatives as AChE inhibitors, a four-dimensional quantitative structure–activity relationship (4D-QSAR) molecular model was proposed. The data required to perform 4D-QSAR analysis includes 52 compounds reported in the literature, usually analogs, and their measured biological activities in a common assay. The model was generated by a complete set of 4D-QSAR program which was written by our group. The best model was found after trying multiple experiments. It had a good predictive ability with the cross-validation correlation coefficient Q2 = 0.77, the internal validation correlation coefficient R2 = 0.954, and the external validation correlation coefficient R2pred = 0.715. The molecular docking analysis was also carried out to understand exceedingly the interactions between flavonoids and the AChE targets, which was in good agreement with the 4D-QSAR model. Based on the information provided by the 4D-QSAR model and molecular docking analysis, the idea for optimizing the structures of flavonoids as AChE inhibitors was put forward which maybe provide theoretical guidance for the research and development of new AChE inhibitors.
This letter presents a new mixed-order MUSIC algorithm for far-field and near-field sources localization using a sparse symmetric array. By exploiting the special array geometry, the proposed ...algorithm constructs a cumulant matrix to estimate the directions of arrival (DOAs) of both far-field and near-field sources using the conventional MUSIC method. With the estimated DOAs and the covariance matrix of the sparse array, the far-field and near-field sources are identified and the range parameters of near-field sources are also obtained by defining the range spectrum. Compared with the traditional algorithms, the proposed algorithm has moderate computation complexity, and provides higher resolution, and also improves the parameters estimation accuracy. Simulation results are provided to demonstrate the performance improvement of the proposed method.
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