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1.
J Basic Microbiol ; 61(2): 165-176, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33448033

RESUMO

Sugarcane/peanut intercropping is a highly efficient planting pattern in South China. However, the effects of sugarcane/peanut intercropping on soil quality need to be clarified. This study characterized the soil microbial community and the soil quality in sugarcane/peanut intercropping systems by the Illumina MiSeq platform. The results showed that the intercropping sugarcane (IS) system significantly increased the total N (TN), available N (AN), available P (AP), pH value, and acid phosphatase activity (ACP), but it had little effect on the total P (TP), total K (TK), available K (AK), organic matter (OM), urease activity, protease activity, catalase activity, and sucrase activity, compared with those in monocropping sugarcane (MS) and monocropping peanut (MP) systems. Both intercropping peanut (IP) and IS soils contained more bacteria and fungi than soils in the MP and MS fields, and the microbes identified were mainly Chloroflexi and Acidobacteria, respectively. Intercropping significantly increased the number of unique microbes in IS soils (68 genera), compared with the numbers in the IP (14), MS (17), and MP (16) systems. The redundancy analysis revealed that the abundances of culturable Acidobacteriaceae subgroup 1, nonculturable DA111, and culturable Acidobacteria were positively correlated with the measured soil quality in the intercropping system. Furthermore, the sugarcane/peanut intercropping significantly increased the economic benefit by 87.84% and 36.38%, as compared with that of the MP and MS, respectively. These results suggest that peanut and sugarcane intercropping increases the available N and P content by increasing the abundance of rhizospheric microbes, especially Acidobacteriaceae subgroup 1, DA111, and Acidobacteria.

2.
Spectrochim Acta A Mol Biomol Spectrosc ; 244: 118837, 2021 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-32866804

RESUMO

Lanzhou lily is a famous lily variety in China, which has many advantages different from other lily varieties. It is rich in nutrients and can be used as medicine or food. The present study is performed to evaluate the quality of Lanzhou lily by Raman spectroscopy. Here, Raman spectra of lily bulbs were collected by confocal Raman microscopy. Through study of a variety of samples, we found that Raman peaks of several important nutrients including starch, sucrose and amino acids were clearly observed from scales of lily bulb, while strong characteristic peaks of ferulic acid were observed at the epidermis of the same scale due to the stimulation of the external environment. We also compared lily bulbs with various sizes and shapes using an average Raman spectrum of selected area. Then, changes of nutrients were quantitively analyzed in different storage period. The results show that the nutrient components including starch, sucrose, amino acids and ferulic acid can be evaluated by Raman spectroscopy. Then the quality of Lanzhou lily can be evaluated by Raman spectroscopy. This is valuable for quality evaluation of lily using non-destructive methods.

3.
Neurosci Bull ; 2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33355899

RESUMO

Tweety-homolog 1 (Ttyh1) is expressed in neural tissue and has been implicated in the generation of several brain diseases. However, its functional significance in pain processing is not understood. By disrupting the gene encoding Ttyh1, we found a loss of Ttyh1 in nociceptors and their central terminals in Ttyh1-deficient mice, along with a reduction in nociceptor excitability and synaptic transmission at identified synapses between nociceptors and spinal neurons projecting to the periaqueductal grey (PAG) in the basal state. More importantly, the peripheral inflammation-evoked nociceptor hyperexcitability and spinal synaptic potentiation recorded in spinal-PAG projection neurons were compromised in Ttyh1-deficient mice. Analysis of the paired-pulse ratio and miniature excitatory postsynaptic currents indicated a role of presynaptic Ttyh1 from spinal nociceptor terminals in the regulation of neurotransmitter release. Interfering with Ttyh1 specifically in nociceptors produces a comparable pain relief. Thus, in this study we demonstrated that Ttyh1 is a critical determinant of acute nociception and pain sensitization caused by peripheral inflammation.

4.
Front Aging Neurosci ; 12: 162, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32581772

RESUMO

Mobile phone use has rapidly increased worldwide, and pregnant women are passively or actively exposed to the associated electromagnetic radiation. Maternal cell phone exposure is related to behavioral difficulties in young offspring. However, whether prenatal mobile phone exposure can predispose the elderly offspring to cognitive impairment is unclear. The enriched environment (EE) has shown positive effects on cognition in an immature brain, but its impact on aging offspring after prenatal cell phone exposure is unknown. This study aimed to investigate whether prenatal exposure to mobile phone exerts long-term effects on cognition in elderly rat offspring and whether EE during adulthood can rescue cognitive impairment by altering the synaptic plasticity. Pregnant rats were subjected to prenatal short-term or long-term cell phone exposure and offspring rats were randomly assigned to standard or EE. Spatial learning and memory were investigated using Morris water maze (MWM) in elderly rat offspring. Hippocampal cellular morphology was assessed by hematoxylin-eosin staining and synaptic ultrastructure was evaluated with transmission electron microscopy. Expression of synaptophysin (SYN), postsynaptic density-95 (PSD-95), and brain-derived neurotrophic factor (BDNF) were detected by western blot. The results demonstrated that prenatal long-term but not short-term exposure to mobile phone lead to cognitive impairment, morphological changes in the hippocampal cells, reduced synaptic number, decreased SYN, PSD-95, and BDNF expression in elderly offspring, which were alleviated by postnatal EE housing. These findings suggest that prenatal long-term mobile phone exposure may pose life-long adverse effects on elderly offspring and impair cognition by disrupting the synaptic plasticity, which may be reversed by postnatal EE housing.

5.
BMC Biotechnol ; 20(1): 13, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111197

RESUMO

BACKGROUND: Intercropping, an essential cultivation pattern in modern agricultural systems, increases crop yields and soil quality. Cassava and peanut intercropping systems exhibit advantages in solar utilization and cadmium absorption, etc. However, the inner mechanisms need to be elucidated. In this study, Illumina MiSeq platform was used to reveal the rhizospheric microbes and soil quality in cassava/peanut intercropping systems, and the results provided a reference for the application of this method in studying other intercropping systems. RESULTS: Both intercropping cassava/peanut (IP) and intercropping peanut/cassava (IC) systems significantly increased available N, available K, pH value, and urease activity, comparing with that in monocropping cassava (MC) and monocropping peanut (MP) system. However, there were few effects on the total N, total P, total K, available P, organic matter, protease activity, catalase activity, sucrase activity, and acid phosphatase activity. Both IP and MP soils contained more bacteria and fungi than those in the IC and MC soils, which were mainly made of Proteobacteria and Actinobacteria. Intercropping remarkably increased the number of Nitrospirae in IP and IC soils comparing those in MC and MP soils. Redundancy analysis (RDA) revealed that the abundances of DA101, Pilimelia, and Ramlibacter were positively correlated to the soil quality. These results suggest that intercropping enhances the available nitrogen content of soil through increasing the quantity of rhizospheric microbes, especially that of DA101 and Pilimelia. CONCLUSIONS: The cassava/peanut intercropping system improves soil quality through increasing the available nitrogen content and abundance of DA101, Pilimelia, and Ramlibacter in the soil.


Assuntos
Agricultura/métodos , Arachis/crescimento & desenvolvimento , Bactérias/classificação , Fungos/classificação , Manihot/crescimento & desenvolvimento , Nitrogênio/metabolismo , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Produtos Agrícolas/crescimento & desenvolvimento , Fungos/crescimento & desenvolvimento , Fungos/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , Potássio/metabolismo , Rizosfera , Análise de Sequência de DNA , Solo/química , Microbiologia do Solo
6.
Spectrochim Acta A Mol Biomol Spectrosc ; 225: 117483, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31493713

RESUMO

Heavy metal pollution has become an important issue threatening human health and the liver is a very important metabolic organ. Here, we use label-free Raman confocal imaging to study the alterations of the liver tissue after cadmium pollution. Raman imaging has been performed on 100µmx100µm liver tissues to study the distribution of important macromolecules and the average Raman spectrum of the entire region has been used to characterize and quantize the change of biochemical compositions in liver tissue. The poisoned livers displayed a significant decrease in the intensity of 748 cm-1, 1128 cm-1 and 1585 cm-1 bands of cytochrome C, in comparison to the control. The collagen peak at 1082 cm-1 is significantly higher than that of control, suggesting the increasing fibrosis of Cd liver tissues. To confirm the results, we selected a 30µmx15µm liver cell area for high-resolution Raman imaging. We observed a substantial increase of lipids and proteins at specific points of hepatocytes. The confocal Raman imaging of liver tissues provided a unique tool to better understand disease-induced changes in the biochemical phenotype of primary liver tissues. Our study provides valuable references as in vitro models for studying Cd accumulation and toxicity in human liver.


Assuntos
Intoxicação por Cádmio/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Análise Espectral Raman/métodos , Animais , Intoxicação por Cádmio/patologia , Modelos Animais de Doenças , Humanos , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal/métodos
7.
Cell Death Dis ; 10(12): 869, 2019 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-31740664

RESUMO

Extracellular vesicles (EVs) including exosomes can serve as mediators of cell-cell communication under physiological and pathological conditions. However, cargo molecules carried by EVs to exert their functions, as well as mechanisms for their regulated release and intake, have been poorly understood. In this study, we examined the effects of endothelial cells-derived EVs on neurons suffering from oxygen-glucose deprivation (OGD), which mimics neuronal ischemia-reperfusion injury in human diseases. In a human umbilical endothelial cell (HUVEC)-neuron coculture assay, we found that HUVECs reduced apoptosis of neurons under OGD, and this effect was compromised by GW4869, a blocker of exosome release. Purified EVs could be internalized by neurons and alleviate neuronal apoptosis under OGD. A miRNA, miR-1290, was highly enriched in HUVECs-derived EVs and was responsible for EV-mediated neuronal protection under OGD. Interestingly, we found that OGD enhanced intake of EVs by neurons cultured in vitro. We examined the expression of several potential receptors for EV intake and found that caveolin-1 (Cav-1) was upregulated in OGD-treated neurons and mice suffering from middle cerebral artery occlusion (MCAO). Knock-down of Cav-1 in neurons reduced EV intake, and canceled EV-mediated neuronal protection under OGD. HUVEC-derived EVs alleviated MCAO-induced neuronal apoptosis in vivo. These findings suggested that ischemia likely upregulates Cav-1 expression in neurons to increase EV intake, which protects neurons by attenuating apoptosis via miR-1290.


Assuntos
Caveolina 1/metabolismo , Células Endoteliais/metabolismo , Vesículas Extracelulares/metabolismo , MicroRNAs/metabolismo , Neurônios/metabolismo , Animais , Apoptose , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Regulação para Cima
8.
J Biophotonics ; 12(12): e201900157, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31407491

RESUMO

Cadmium (Cd) is a toxic heavy metal which is harmful to environment and organisms. The reabsorption of Cd in kidney leads it to be the main damaged organ in animals under the Cd exposure. In this work, we applied confocal Raman spectroscopy to map the pathological changes in situ in normal and Cd-exposed mice kidney. The renal tissue from Cd-exposed group displayed a remarkable decreasing in the intensity of typical peaks related to mitochondria, DNA, proteins and lipids. On the contrary, the peaks of collagen in Cd-exposed group elevated significantly. The components in each tissue were identified and distinguished by principal component analysis. Furthermore, all the biological investigations in this study were consistent with the Raman spectrum detection, which revealed the progression and degree of lesion induced by Cd. The confocal Raman spectroscopy provides a new perspective for in situ monitoring of substances changes in tissues, which exhibits more comprehensive understanding of the pathogenic mechanisms of heavy metals in molecular toxicology.


Assuntos
Cádmio/toxicidade , Rim/efeitos dos fármacos , Análise Espectral Raman , Animais , Rim/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL
9.
Biochem Biophys Res Commun ; 514(3): 842-847, 2019 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-31079925

RESUMO

Mammalian neural stem cells (NSCs) are not only responsible for normal development of the central nervous system (CNS), but also participate in brain homeostasis and repair, thus hold promising clinical potentials in the treatment of neurodegenerative diseases and trauma. However the molecular networks regulating the stemness and differentiation of NSCs have not been fully understood. In this study, we show that Tweety-homolog 1 (Ttyh1), a five-pass transmembrane protein specifically expressed in mouse brain, is involved in maintaining stemness of murine NSCs. Blocking or activating Notch signal led to downregulation and upregulation of Ttyh1 in cultured NSCs, respectively, suggesting that Ttyh1 is under the control of Notch signaling. Knockdown of Ttyh1 in cultured NSCs resulted in a transient increase in the number and size of neurospheres, followed by a decrease of stemness as manifested by compromised neurosphere formation, downregulated stem cell markers, and increased neuronal differentiation. We generated Ttyh1 knockout mice by deleting its exon 4 using the CRISPR-Cas9 technology. Surprisingly, in contrast to a previous report, Ttyh1 knockout did not result in embryonic lethality. NSCs derived from Ttyh1 knockout mice phenocopied NSCs transfected with Ttyh1 siRNA. Immunofluorescence showed that loss of Ttyh1 leads to the increase of neurogenesis in adult mice. Taken together, these findings indicate that Ttyh1, which is likely downstream to Notch signaling, plays an important role in regulating NSCs.


Assuntos
Diferenciação Celular , Proteínas de Membrana/deficiência , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Receptores Notch/metabolismo , Transdução de Sinais , Animais , Perda do Embrião/patologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Neurogênese
10.
Zhongguo Zhong Yao Za Zhi ; 44(4): 803-810, 2019 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-30989895

RESUMO

To mine and discover the active components of " Coptidis Rhizome-Magnoliae Officinalis Cortex( C&M) " based on the network pharmacology,integrate and analyze the potential targets and mechanisms. The TCMSP database was used to screen active ingredients. TTD and Drug Bank databases were used to predict the potential targets by referring to relevant literature,and the pathway annotation technology was used to enrich and analyze the active ingredients and potential targets of " C&M". A total of 29 potential target active ingredients were screened from " C&M",including 12 alkaloids components such as( R)-canadine,berberine,coptisine,and palmatine; 3 lignans consisting of magnolol,honokiol and obovatol; 6 volatile oils consisting of α-eudesmol,ß-eudesmol,eucalyptol and so on,and flavonoids including quercetin and neohesperidin. Corresponding 199 predicted targets were screened out,mainly including PTGS2,PTGS1,NCOA2,Hsp90 AB1,and so on. 72 signaling pathways were involved,8 of which were related to cancer,such as prostate cancer,bladder cancer,and pancreatic cancer; 9 of which were related to endocrine,including oxytocin signaling pathway,insulin signaling pathway,thyroid hormone signaling pathway and so on,as well as inflammation-related pathway. This study has preliminarily mined and discovered the main active components and potential targets of " C&M",providing material source for the study on the preparation of structural components of traditional Chinese medicine.


Assuntos
Medicamentos de Ervas Chinesas , Rizoma , Alcaloides , Humanos , Magnolia , Masculino
11.
J Cell Biochem ; 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30387167

RESUMO

MicroRNAs are involved in osteoclast differentiation. Although miR-199a-5p plays an important role in many different systems and diseases, its function during osteoclastogenesis remains unclear. In this study, we investigated the function and the target gene of miR-199a-5p in osteoclast differentiation. The in vitro data showed that miR-199a-5p was significantly upregulated after the stimulation by receptor activator of nuclear factor kappa-B ligand in macrophages and RAW 264.7 cells. After transfection of miR-199a-5p mimic, the messenger RNA expression level of nuclear factor of activated T-cells cytoplasmic 1, tartrate-resistant acid phosphatase (TRAP), and receptor activator of nuclear factor kappa-B was significantly increased in RAW 264.7 cells and the number of TRAP-positive cells was also increased. MiR-199a-5p inhibitor showed the complete opposite outcome which brought additional proof to our finding. Overexpression of miR-199a-5p led to downregulation of Mafb protein. The luciferase activity was obviously repressed when WT-pGL3-Mafb and miR-199a-5p mimics were cotransfected into 293 T cells and the inhibitors cotransfected demonstrated reverse result. MiR-199a-5p overexpressed during osteoclast differentiation and positively regulated osteoclast formation in vitro by target Mafb.

12.
Neural Regen Res ; 13(7): 1294-1304, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30028342

RESUMO

Neurologic impairments are usually irreversible as a result of limited regeneration in the central nervous system. Therefore, based on the regenerative capacity of stem cells, transplantation therapies of various stem cells have been tested in basic research and preclinical trials, and some have shown great prospects. This manuscript overviews the cellular and molecular characteristics of embryonic stem cells, induced pluripotent stem cells, neural stem cells, retinal stem/progenitor cells, mesenchymal stem/stromal cells, and their derivatives in vivo and in vitro as sources for regenerative therapy. These cells have all been considered as candidates to treat several major neurological disorders and diseases, owing to their self-renewal capacity, multi-directional differentiation, neurotrophic properties, and immune modulation effects. We also review representative basic research and recent clinical trials using stem cells for neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease, and age-related macular degeneration, as well as traumatic brain injury and glioblastoma. In spite of a few unsuccessful cases, risks of tumorigenicity, and ethical concerns, most results of animal experiments and clinical trials demonstrate efficacious therapeutic effects of stem cells in the treatment of nervous system disease. In summary, these emerging findings in regenerative medicine are likely to contribute to breakthroughs in the treatment of neurological disorders. Thus, stem cells are a promising candidate for the treatment of nervous system diseases.

13.
Zhongguo Zhong Yao Za Zhi ; 43(23): 4709-4717, 2018 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-30717562

RESUMO

The aim of this paper was to find out the active components of Epimedium brevicornum using network pharmacology, and find the potential targets and mechanisms. The TCMSP database was used to screen the active ingredients, and TTD and DrugBank databases were used to predict the potential targets with the literature mining. The pathway annotation was used to enrich and analyze the active ingredients and potential targets of E. brevicornum. The results showed that E. brevicornum had34 potential target active ingredients, including 21 flavones components, such as icariin, epimedin A, epimedin B, epimedin C, Yinyanghuo A, Yinyanghuo C and so on, 2 lignans involved in (+)-cycloolivil and olivil, 3 sterols consisting of sitosterol, 24-epicampesterol and poriferast-5-en-3beta-ol. The main predicted targets included Ptgs2, NCOA6, RANK, OPG, WNT9B, PTH1R, BMPs, SMAD4A and so on. There were 88 signaling pathways involved in 10 signaling pathways which was related to inflammation, such as NF-kappa B signaling pathway, T cell receptor signaling pathway, IL-17 signaling pathway and 10 pathways which was related to cancer included breast cancer, bladder cancer, pancreatic cancer and so on, and estrogen related signaling pathways included estrogen signaling pathway. This laid the foundation for the discovery of the active components of Epimedium and the study on its mechanism of action.


Assuntos
Epimedium/metabolismo , Epimedium/classificação , Estrogênios , Flavonoides , Transdução de Sinais
14.
Biochem Biophys Res Commun ; 495(1): 892-898, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29154990

RESUMO

The neural stem cell (NSC) niche in subventricular zone (SVZ) of adult mammalian brain contains dense vascular plexus, where endothelial cells (ECs) regulate NSCs by releasing plenty of angiocrine factors. However, the role of ECs-derived exosomes, a novel type of mediators of intercellular communications, in the regulation of NSCs remains unclear. In the current study, primary NSCs isolated from embryonic mouse brains form more neurospheres when cultured in the presence of human umbilical vein endothelial cells (HUVECs). The supportive role of ECs in the coculture was significantly attenuated when GW4869, a blocker of exosome formation, was included, suggesting that HUVECs-derived exosomes played a significant role in supporting NSCs. In order to investigate the role of ECs-derived exosomes on NSCs, we collected exosomes from HUVECs. We found that HUVECs-derived exosomes could significantly promote the formation of neurospheres by primary murine NSCs. EdU incorporation and TUNEL assays indicated that the proliferation of NSCs increased while apoptosis decreased when cultured in the presence of HUVECs-derived exosomes. NSCs incubated with the HUVECs-derived exosomes maintained their potential of multi-lineage differentiation potentials. The expression of stemness-related genes was up-regulated. These data suggested that ECs-derived exosomes could play an importantly role in NSC niche, and they might be used as a reagent for ex vivo NSC amplification for medical application.


Assuntos
Diferenciação Celular/fisiologia , Exossomos/metabolismo , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/fisiologia , Células-Tronco Neurais/citologia , Células-Tronco Neurais/fisiologia , Nicho de Células-Tronco/fisiologia , Células Cultivadas , Humanos
15.
J Opt Soc Am A Opt Image Sci Vis ; 33(2): 192-204, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26831770

RESUMO

Enhancing the color saturation of objects via illumination with specially designed light spectra is promising in many commercial and scientific applications. Existing literature has focused on studying the colors that can be rendered by white light with various correlated color temperatures, and by the mixed light from various monochromatic light-emitting diodes. However, very little literature has been devoted to methods that can actively configure the light spectrum to enhance the color saturation of an arbitrary object. This paper proposes an optimization-based method to extend the gamut that can be achieved by a given polychromatic lamp toward a chosen direction, i.e., to increase the saturation of a specific color. Moreover, to trade-off the increased saturation of a color sample with the reduced colorfulness of other samples, constraints with tunable thresholds are imposed to the optimization problem to bound the variation of a contrast color sample. In addition, the effect of uncontrollable ambient light can be taken into account by mild modifications of the optimization problem. Simulation results show that the optimized light spectrum can effectively enhance the saturation of any specific color, while maintaining the other rendered colors as intact as possible. Visual experiments have also been conducted with 22 human subjects, whose responses agree with the simulation results.

16.
J Opt Soc Am A Opt Image Sci Vis ; 32(7): 1262-70, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-26367155

RESUMO

Enhancing the colorfulness of illuminated objects is a promising application of LED lighting for commercial, exhibiting, and scientific purposes. This paper proposes a method to enhance the color of illuminated objects for a given polychromatic lamp. Meanwhile, the light color is restricted to white. We further relax the white light constraints by introducing soft margins. Based on the spectral and electrical characteristics of LEDs and object surface properties, we determine the optimal mixing of the LED light spectrum by solving a numerical optimization problem, which is a quadratic fractional programming problem by formulation. Simulation studies show that the trade-off between the white light constraint and the level of the color enhancement can be adjusted by tuning an upper limit value of the soft margin. Furthermore, visual evaluation experiments are performed to evaluate human perception of the color enhancement. The experiments have verified the effectiveness of the proposed method.

18.
Huan Jing Ke Xue ; 30(3): 900-6, 2009 Mar 15.
Artigo em Chinês | MEDLINE | ID: mdl-19432348

RESUMO

Based on field investigation and laboratory analysis, the speciation and bioavailability of the heavy metals (Cd, Cu, Pb, and Zn) was studied. These metals were tested from 16 soil samples taken from paddy soils irrigated by acid mine drainage in the lower stream of Dabaoshan mine area, Guangdong Province, China. The toxicity characteristic leaching procedure (TCLP) and three-step community bureau of reference (BCR) sequential extraction procedure methods were used to analyse the bioavailability of heavy metals. TCLP is currently recognized as an international method for evaluation of heavy metal pollution in soils. Two methods were compared in bioavailability by stepwise multiple linear regression analysis. Cd was dominated mainly by the acid-extractable and residual fractions, and followed by the order of acid-extractable > residual > oxidisable > reducible. Cu was dominated mainly by the residual fraction, and decreased in the following order: residual > reducible > acid-extractable > oxidisable. Pb was dominantly released in the reducible and residual fractions, they account for 86.54% of the total contents, and decreased in the following order: reducible > residual > acid-extractable > oxidisable. Zn was dominated mainly by the residual fraction, it takes more than 50% of the total contents, and followed by the order of residual > acid-extractable > reducible > oxidisable. The levels of Cd, Cu, Pb and Zn extracted by TCLP were 0.17-0.89, 8.12-70.33, 3.16-90.33 and 10.24-106.85 mg x kg(-1), respectively, and the average concentrations of Cd, Cu, Pb and Zn were 0.41, 36.60, 15.97 and 50.78 mg x kg(-1), respectively. The concentrations of Cd, Cu, Ph and Zn in rice seeds were 0.183-0.947, 3.542-5.997, 0.285-1.532 and 17.54-41.10 mg x kg(-1), respectively. Comparing to the national standards on heavy metals in foods by the Chinese Ministry of Health, the contents of Cu and Zn in rice seeds didn't exceed the upper limit, while the contents of Cd and Pb in rice seeds exceed the upper limit by 87.50% and 81.25%, respectively. Results of the stepwise multiple linear regression analysis revealed that contents of Cd and Zn in seeds of rice were significantly influenced by contents of acid-extractable Cd and Zn, that contents of Cu in seeds of rice were significantly influenced by contents of acid-extractable and oxidisable Cu, and the contents of Pb in seeds of rice were significantly influenced by contents of reducible Pb and organic matter. Contents of four metals in seeds of rice were significantly influenced by contents of metals extracted by TCLP, and the influences of total content, pH and organic matter were not significant. In short, TCLP method was fast, simple and suitable for evaluation of bioavailability of heavy metals in sewage-irrigated paddy soils by acid mine drainage.


Assuntos
Resíduos Industriais/análise , Metais Pesados/análise , Mineração , Oryza/crescimento & desenvolvimento , Poluentes do Solo/análise , Ácidos/análise , Cádmio/análise , Cádmio/toxicidade , China , Cobre/análise , Cobre/toxicidade , Monitoramento Ambiental , Ferro , Chumbo/análise , Chumbo/toxicidade , Metais Pesados/toxicidade , Poluentes do Solo/toxicidade , Poluentes Químicos da Água/análise
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