RESUMO
Accumulating evidence has shown that miR-429 plays an important role in the development and progression of tumour. However, the role of miR-429 in glioblastoma multiforme (GBM) remains largely unknown. The present study is designed to investigate the function of miR-429 in GBM and to explore the molecular mechanism underlying its function. The expression level of miR-429 was detected in GBM tissues and cell lines by quantitative real-time polymerase chain reaction. The effect of overexpression of miR-429 on in vitro cell proliferation, apoptosis and invasion was examined. Western blot analysis was used to detect the influence of miR-429 on the expression of target gene, and Pearson analysis was used to calculate the correlation between the expression of targets gene and the miR-429 in GBM tissues. Our study shows that miR-429 is downregulated in GBM tissues compared with noncancerous tissues (P < .01). In addition, the expression of miR-429 in GBM cell lines is also significantly lower (P < .01). Enforced expression of miR-429 inhibits GBM cells proliferation, induces apoptosis and suppresses invasion and leads to the downregulation of the SOX2 protein. Moreover, the expression level of miR-429 in GBM tissues shows inverse relationship with the expression level of SOX2 protein. Our findings suggest that miR-429 represents a potential tumour-suppressive miRNA and plays an important role in GBM progression by directly targeting SOX2.
Assuntos
Proliferação de Células/genética , Glioblastoma/genética , MicroRNAs/genética , Fatores de Transcrição SOXB1/genética , Apoptose/genética , Linhagem Celular Tumoral , Feminino , Regulação Neoplásica da Expressão Gênica , Glioblastoma/patologia , Humanos , Masculino , MicroRNAs/biossíntese , Invasividade Neoplásica/genética , Fatores de Transcrição SOXB1/biossínteseRESUMO
This study was conducted to evaluate the quality of surface water and shallow groundwater near a rare earth mining area in southern Jiangxi Province, China. Water samples from paddy fields, ponds, streams, wells, and springs were collected and analyzed. The results showed that water bodies were characterized by low pH and high concentrations of total nitrogen (total N), ammonium nitrogen (NH4 (+)-N), manganese (Mn), and rare earth elements (REEs), which was likely due to residual chemicals in the soil after mining activity. A comparison with the surface water standard (State Environmental Protection Administration & General Administration of Quality Supervision, Inspection and Quarantine of China GB3838, 2002) and drinking water sanitary standard (Ministry of Health & National Standardization Management Committee of China GB5749, 2006) of China revealed that 88 % of pond and stream water samples investigated were unsuitable for agricultural use and aquaculture water supply, and 50 % of well and spring water samples were unsuitable for drinking water. Moreover, significant cerium (Ce) negative and heavy REEs enrichment was observed after the data were normalized to the Post-Archean Australian Shales (PAAS). Principal component analysis indicated that the mining activity had a more significant impact on local water quality than terrace field farming and poultry breeding activities. Moreover, greater risk of water pollution and adverse effects on local residents' health was observed with closer proximity to mining sites. Overall, these findings indicate that effective measures to prevent contamination of surrounding water bodies from the effects of mining activity are needed.
Assuntos
Monitoramento Ambiental , Água Subterrânea/química , Mineração , Poluentes da Água/análise , Agricultura , China , Qualidade da ÁguaRESUMO
Many crop plants are exposed to heavy metals and other metals that may intoxicate the crop plants themselves or consumers of the plants. The rhizotoxicity of heavy metals is influenced strongly by the root cell plasma membrane (PM) surface's electrical potential (ψ0). The usually negative ψ0 is created by negatively charged constituents of the PM. Cations in the rooting medium are attracted to the PM surface and anions are repelled. Addition of ameliorating cations (e.g., Ca2+ and Mg2+) to the rooting medium reduces the effectiveness of cationic toxicants (e.g., Cu2+ and Pb2+) and increases the effectiveness of anionic toxicants (e.g., SeO42- and H2AsO4-). Root growth responses to ions are better correlated with ion activities at PM surfaces ({IZ}0) than with activities in the bulk-phase medium ({IZ}b) (IZ denotes an ion with charge Z). Therefore, electrostatic effects play a role in heavy metal toxicity that may exceed the role of site-specific competition between toxicants and ameliorants. Furthermore, ψ0 controls the transport of ions across the PM by influencing both {IZ}0 and the electrical potential difference across the PM from the outer surface to the inner surface (Em,surf). Em,surf is a component of the driving force for ion fluxes across the PM and controls ion-channel voltage gating. Incorporation of {IZ}0 and Em,surf into quantitative models for root metal toxicity and uptake improves risk assessments of toxic metals in the environment. These risk assessments will improve further with future research on the application of electrostatic theory to heavy metal phytotoxicity in natural soils and aquatic environments.
RESUMO
Land application of biochar is increasingly being considered for potential agronomic and environmental benefits, e.g., enhancing carbon sequestration, nutrient retention, water holding capacity, and crop productivity; and reducing greenhouse gas emissions and bioavailability of environmental contaminants. However, little is known about the transport of biochar particles in the aqueous environment, which represents a critical knowledge gap because biochar particles can facilitate the transport of adsorbed contaminants. In this study, column experiments were conducted to investigate biochar particle transport and retention in water-saturated quartz sand. Specific factors considered included biochar feedstocks (wheat straw and pine needle), pyrolysis temperature (350 and 550 °C), and particle size (micrometer-particle (MP) and nanoparticle (NP)). Greater mobility was observed for the biochars of lower pyrolysis temperatures and smaller particle sizes. Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) calculations that considered measured zeta potentials and Lewis acid-base interactions were used to better understand the influence of pyrolysis temperature on biochars particle transport. Most biochars exhibited attractive acid-base interactions that impeded their transport, whereas the biochar with the greatest mobility had repulsive acid-base interaction. Nonetheless, greater retention of the MPs than that of the NPs was in contrast with the XDLVO predictions. Straining and biochar surface charge heterogeneity were found to enhance the retention of biochar MPs, but played an insignificant role in the biochar NP retention. Experimental breakthrough curves and retention profiles were well-described using a two-site kinetic retention model that accounted for depth-dependent retention at one site. Modeled first-order retention coefficients on both sites 1 and 2 increased with increasing pyrolysis temperature and particle size.
Assuntos
Carvão Vegetal/química , Movimento (Física) , Dióxido de Silício/química , Água/química , Adsorção , Biomassa , Nanopartículas/química , Nanopartículas/ultraestrutura , Tamanho da Partícula , Pinus/química , Eletricidade Estática , Temperatura , Triticum/químicaRESUMO
The usually negative, but variable electrical potential (ψ0) at the cell membrane (CM) surface influences the surface activities of free ions and the electrical driving force for the transport of ions across the CM. The rhizotoxic effects and uptake of Zn(2+) and Co(2+) singly and in binary mixture in wheat ( Triticum aestivum L.) at three pH values (4.5, 5.5, or 6.1) were examined in terms of the free ion activities of Zn(2+), Co(2+), and H(+) at the CM surface (these ions are denoted {M(n+)}(0)). Toxicity and uptake of Zn(2+) or Co(2+) singly to roots were better correlated with {M(2+)}(0) than with their bulk-phase activities. Studies of toxicant interactions using the electrostatic approach and a response-multiplication model for toxicant mixtures indicated that {Co(2+)}(0) significantly enhanced the toxicity of {Zn(2+)}(0), but {Zn(2+)}(0) did not significantly affect the toxicity of {Co(2+)}(0). {H(+)}(0) substantially enhanced the toxicity of both metal ions. Taking ψo into account improved the correspondence (denoted r(2)) between observed and predicted uptake of both Zn(2+) and Co(2+), and each inhibited the uptake of the other. Results showed that r(2) increased from 0.776 to 0.936 for Zn uptake and improved from 0.805 to 0.951 for Co uptake. Thus electrostatic models for metal toxicity and uptake proved superior to models incorporating only bulk-phase activities of ions.
Assuntos
Cátions Bivalentes/toxicidade , Cobalto/toxicidade , Raízes de Plantas/crescimento & desenvolvimento , Triticum/crescimento & desenvolvimento , Zinco/toxicidade , Transporte Biológico , Cátions Bivalentes/metabolismo , Membrana Celular/metabolismo , Cobalto/metabolismo , Modelos Biológicos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Eletricidade Estática , Triticum/efeitos dos fármacos , Triticum/metabolismo , Zinco/metabolismoRESUMO
This study evaluated the effects of theaflavins (TFs), tea polyphenols (TP) and vitamin C (VC) on the nitrite residue amount, color, antioxidant capacity and N-nitrosamines inhibition in cured sausage. The addition of TFs, TP and VC combined with NaNO2 respectively could significantly increase the a* value, nitroso pigment content and DPPH free radical scavenging rate, and effectively reduced the content of residual nitrite, metmyoglobin (MetMb) and total N-nitrosamines in cured sausages than treated only with NaNO2 (P < 0.05), of which TFs group was the most significant (P < 0.05). It was indicated that the addition of TFs, TP could better inhibit the oxidation of cured sausages. UV-vis spectroscopy also showed pentacoordinate nitrosyl ferrohemochrome was the main pigment component in the samples. The results demonstrated that TFs and TP could contribute to the desired color and safety of sausage.
Assuntos
Nitrosaminas , Polifenóis , Antioxidantes , Biflavonoides , Catequina , Nitritos , Chá/químicaRESUMO
The present study aimed to ascertain the potential roles and mechanisms of action of micro (mi)RNA22 in ischemic stroke. The results indicated that miRNA22 expression was downregulated in ischemic stroke rats model, compared with a control group. The downregulation of miRNA22 upregulated the expression of inflammatory factors [including tumor necrosis factorα, interleukin (IL)1ß, IL6 and IL18]. It could also induce the expression of macrophage inflammatory protein (MIP2), prostaglandin E2 (PGE2), cyclooxygenase2 (COX2) and inducible NO synthase (iNOS) in the in vitro model. By contrast, the overexpression of miRNA22 downregulated the expression of inflammatory factors, and suppressed the expression of MIP2, PGE2, COX2 and iNOS in the in vitro model. The downregulation of miRNA22 induced the protein expression of nuclear factor (NF)κB and phosphorylatedp38 (pp38) mitogenactivated protein kinase (MAPK) in the in vitro model. By comparison, the overexpression of miRNA22 suppressed the protein expression of NFκB and pp38 in the in vitro model. Typically, LY2228820, the p38 inhibitor (3 nM) would mitigate the proinflammatory effects of antimiRNA22 in the in vitro model. These results suggested that miRNA22 can alleviate ischemic strokeinduced inflammation in rats model or vitro model through p38 MAPK/NFκB pathway suppression.
Assuntos
Isquemia Encefálica/genética , Inflamação/genética , MicroRNAs/genética , Acidente Vascular Cerebral/genética , Animais , Isquemia Encefálica/patologia , Ciclo-Oxigenase 2/genética , Dinoprostona/genética , Humanos , Imidazóis/farmacologia , Inflamação/patologia , Fosforilação/efeitos dos fármacos , Piridinas/farmacologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Acidente Vascular Cerebral/patologia , Fator de Necrose Tumoral alfa/genética , Proteínas Quinases p38 Ativadas por Mitógeno/genéticaRESUMO
In previous years, it has been found that Rhodiola has a wide range of pharmacological effects in diseases of the cardiovascular system, as it can remove superoxide anions and hydroxyl radicals in chemical reactions. Behavioral assessment was used to measure cognitive impairment. Inflammation, oxidative stress and caspase3 activity were measured using commercial kits. Western blot analysis was used to measure Rho/Rhoassociated kinase (ROCK)/sirtuin 1 (SIRT1)/nuclear factor (NF)κB protein expression. The objective of the present study was to investigate the protective effect of salidroside on diabetes and diabetesinduced cognitive impairment. The results of the study demonstrated that salidroside prevented cognitive impairment, decreased serum blood glucose levels and increased body weight, reduced fasting blood glucose levels and blood lipid levels, and inhibited oxidative stress, inflammation and nerve cell apoptosis in the diabetic rat model. Salidroside suppressed ROCK/ SIRT1 NFκB pathway and protein expression in the diabetic rats. These data showed that salidroside prevented diabetesinduced cognitive impairment by regulating the Rho/ROCK/SIRT1/NFκB pathway.
Assuntos
Disfunção Cognitiva/prevenção & controle , Diabetes Mellitus Experimental/complicações , Regulação da Expressão Gênica/efeitos dos fármacos , Glucosídeos/farmacologia , Fenóis/farmacologia , Quinases Associadas a rho/metabolismo , Animais , Apoptose , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/patologia , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Quinases Associadas a rho/genéticaRESUMO
When manures from intensive livestock operations are applied to agricultural or vegetable fields at a high rate, large amounts of salts and metals will be introduced into soils. Using a column leaching experiment, this study assessed the leaching potential of the downward movement of Cu and Zn as well as some salt ions after an intensive farm pig manure at rates of 0%, 5% and 10% (w/w) were applied to the top 20 cm of two different textured soils (G soil -sandy loam soil; H soil-silty clay loam soil), and investigated the growth of amaranth and Cu and Zn transfer from soil to amaranth (Amaranthus tricolor). Soil solutions were obtained at 20, 40 and 60 cm depth of the packed column and analyzed for pH, electrical conductivity (EC), dissolved organic matter (DOC) and Cu and Zn concentrations. The results indicated that application of pig manure containing Cu and Zn to sandy loam soil might cause higher leaching and uptake risk than silty clay loam soil, especially at high application rates. And manure amendment at 5% and 10% significantly decreased the biomass of amaranth, in which the salt impact rather than Cu and Zn toxicity from manures played more important role in amaranth growth. Thus the farmer should avoid application the high rate of pig manure containing metal and salt to soil at a time, especially in sandy soil.
Assuntos
Amaranthus/efeitos dos fármacos , Cobre , Monitoramento Ambiental , Esterco , Poluentes do Solo , Zinco , Amaranthus/crescimento & desenvolvimento , Amaranthus/metabolismo , Animais , Cobre/análise , Cobre/metabolismo , Cobre/toxicidade , Condutividade Elétrica , Concentração de Íons de Hidrogênio , Compostos Orgânicos/química , Compostos Orgânicos/metabolismo , Medição de Risco , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidade , Solubilidade , Suínos , Fatores de Tempo , Zinco/análise , Zinco/metabolismo , Zinco/toxicidadeRESUMO
Heavy metal stress in culture media is always rhizotoxic. Our study aims to investigate the role of negative potential (ψ 0) at root cell membrane surface (CMs) on modeling Zn2+ toxicity to wheat seedling roots and to examine the effects of different nitrogen forms (NH4+ and NO3-) on ψ 0 and Zn rhizotoxicity. Solution culture experiments were conducted to measure the root elongation and Zn accumulation under Zn2+ exposure. The role of two nitrogen forms in affecting Zn2+ toxicity was compared, giving particular consideration to ψ 0 and Zn2+ activities at CMs ({Zn2+}0). Results showed that NH4+ alleviates Zn2+ rhizotoxicity and NO3- increases Zn2+ rhizotoxicity. In modeling the rhizotoxicity, root length correlated better with {Zn2+}0 than {Zn2+}b, and the predictive accuracy (r 2) of NH4+ treatment increased from 0.748 to 0.917 when incorporation of {Zn2+}0 and {Ca2+}0 into analysis. Oppositely, ψ 0 played a limited role in modeling Zn2+ rhizotoxicity and bioavailability in NO3- treated medium (r 2 = 0.609). Moreover, higher concentration of Zn in roots was found in NO3- treatment, compared with the NH4+ treatment. ψ 0 rather than the rhizotoxicity data correlated better with Zn accumulation especially in the NO3- treatment (r 2 > 0.7), which meant the electrical driving force at CMs playing a dominant role in modeling the metal accumulation. In conclusion, the alleviatory role of NH4+ on Zn toxicity and uptake was well explained and modeled by electrostatic effects at CMs. Though our data do not explore mechanisms for the NO3--Zn2+ interactions, we propose that ψ 0 worked better in affecting the driving force for root Zn uptake, than influencing metal bioavailability at CMs.
Assuntos
Nitrogênio/fisiologia , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Zinco/toxicidade , Transporte Biológico , Membrana Celular/efeitos dos fármacos , Membrana Celular/fisiologia , Eletrofisiologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/fisiologia , Plântula/efeitos dos fármacos , Plântula/fisiologia , Poluentes do Solo/química , Triticum/fisiologia , Zinco/químicaRESUMO
A pilot-scale experiment for electrokinetic treatment of 700 kg of copper contaminated red soil was conducted using a constant voltage of 80 V. Dynamic removal percentages of Cu from the soil and energy consumption during the treatment were evaluated together with changes of soil pH, electrical conductivity and soil microbial functional diversity before and after the electrokinetic treatment. The results indicate that 76% of Cu was successfully removed from the soil after 140 d of treatment when lactic acid was used as enhancing reagent for adjusting the catholyte pH and dissolving soil Cu by complexation, and the pilot-scale electrokinetic experiment consumed electric energy of 224 kW h t-1 soil. The post-treatment soil pH values decreased about 0.1-1.6 units compared with the initial value (pH 4.8), and soil electrical conductivities in most of soil sections also significantly decreased. Soil microbial functional diversity varied after the electrokinetic treatment, particularly the increase of substrate richness index, which is possibly due to the stimulation of lactic acid that was introduced into the soil column during the experiment.
Assuntos
Cobre/análise , Poluentes do Solo/análise , Solo/análise , Condutividade Elétrica , Eletrodos , Concentração de Íons de Hidrogênio , Cinética , Projetos Piloto , Solo/normas , Microbiologia do Solo/normasRESUMO
Agricultural application of large amounts of glyphosate [N-(phosphonomethyl)-glycine] may affect soil metal behaviors to some extend, because glyphosate can react with many kinds of metals to form metal complexes. Cosorption of Zn and glyphosate on a Red soil (RS, Udic Ferrosols) and a Wushan soil (WS, Anthrosol) was studied. In comparison with the WS, the RS has less adsorption capacity for Zn and higher for glyphosate. The presence of glyphosate decreased Zn adsorption on the two soils, which are resulted from the decreased equilibrium solution pH caused by the added glyphosate, and also the formation of water-soluble complexes of glyphosate with solution Zn(2+) that had lower affinity to soil surface in comparison with Zn(2+) itself. Such effect is more significant on the RS than on the WS, mainly because of the less adsorption quantity of Zn on the former one. On the contrary, the presence of Zn increased the adsorption quantities of glyphosate on the RS and WS, which is resulted from the decreasing pH value of the equilibrium solution caused by Zn(2+) exchange with H(+) ions of soil surface. Such results suggest that glyphosate in field may increase the mobility and bioavailability of Zn and correspondingly increase its environmental risk.
Assuntos
Glicina/análogos & derivados , Substâncias Perigosas , Poluentes do Solo , Solo , Zinco/análise , Adsorção , Glicina/análise , Herbicidas , Concentração de Íons de Hidrogênio , Prótons , Zinco/química , Compostos de Zinco , GlifosatoRESUMO
Environmental safety of agricultural utilization of livestock and poultry manures from intensive farming is attracting great attention because the manures often contain high concentrations of heavy metals and organic pollutants. Pot experiments, in which a pig manure (PM), a chicken manure (CM) and a commercial organic manure (OM) with different concentrations of Cu and Zn to simulate soil metal accumulation by manure application for different times were utilized in a garden soil at a rate of 2% (W/W), were conducted to study the effect of application of these livestock and poultry manures on growth of radish (Raphanus sativus L.) and pakchoi (Brassica chinensis L.) as well as their Cu and Zn uptake. The results exhibit that the manures except the PM improved the growth of radish and pakchoi. The difference of biomass among the same manure treatments containing different concentrations of Cu and Zn, however, was insignificant. In addition, application of the livestock and poultry manures significantly increased soil pHs and electric conductivities (EC) compared with the control, which is ascribed that these manures had high pH and contained large amounts of inorganic ions. The available soil Zn concentrations in the PM were higher than that in the CM and OM, and the extractable soil Cu concentrations in the three manures were almost the same after radish growth in the garden soil but were different after pakchoi growth. Zinc and Cu concentrations in the radish and pakchoi tissues increased when the soil Zn and Cu concentrations increased by manures application, but were still within a safe value. An except is the treatment PM4 in which the Zn concentration of the above-ground part of radish was 28.7 mg kg-1, exceeding the Chinese Food Hygiene Standard of 20 mg kg-1 based on fresh weight. Good correlation was obtained between the extractable soil Zn (or Cu) concentrations extracted by 1.0 mol l-1 NH4NO3 and the Zn (or Cu) concentrations in radish and pakchoi tissues, which was expected to be effective in forecasting Cu and Zn availability to radish and pakchoi in manure agronomic utilization.
Assuntos
Brassica/metabolismo , Cobre/farmacocinética , Esterco , Raphanus/metabolismo , Zinco/farmacocinética , Animais , Transporte Biológico/fisiologia , Biomassa , Galinhas , China , Condutividade Elétrica , Concentração de Íons de Hidrogênio , Solo/análise , Espectrofotometria Atômica , Sus scrofaRESUMO
Glyphosate [N-(phosphonomethyl)glycine] (GPS; H3G) is a widely used pesticide throughout the world. It affects metal behaviors in soil-plant system due to its functional groups, which react with metal ions to form metal complexes. Adsorption and cosorption of cadmium and glyphosate on a Wushan soil (WS soil, Anthrosol) and a Zhuanhong soil (ZH soil, Udic Ferrisol) as affect by solution pH were studied by means of batch adsorption experiments. It indicated that the adsorption quantity of Cd or glyphosate was highly relevant to soil characteristics. The WS soil had higher adsorption capacity of Cd than the ZH soil, due to its high organic matter content and cation exchange capacity (CEC). In contrast, the adsorption quantity of glyphosate on the WS soil was less than that on the ZH soil, because the WS soil has lower iron and aluminum oxides content but higher pH than the ZH soil. The herbicide glyphosate affected Cd adsorption on the two soils when they coexisted in a same soil solution, which was attributed to a glyphosate-induced pH-decrease and the corresponding decline in negative surface charges of the soil. Beside that, glyphosate reacted with solution Cd to form the water-soluble complexes that had lower affinity to soil surface in comparison with Cd itself. On the other hand, the presence of Cd in the soil solution also affected the adsorption of glyphosate on the soils. The presence of Cd increased adsorption quantity of glyphosate on the WS and ZH soils, which was resulted from the decrease of equilibrium solution pH caused by Cd2+ exchange with H+ ions of soil surface. In addition to that, glyphosate adsorption possibly takes place on sites where Cd was previously adsorbed and acted as a bridge between the soil and glyphosate.
Assuntos
Cádmio/química , Glicina/análogos & derivados , Glicina/química , Herbicidas/química , Solo/análise , Adsorção , China , Concentração de Íons de Hidrogênio , GlifosatoRESUMO
Speciation and fractionation of heavy metals in soil subsamples experimentally loaded with Pb, Cd, Cu and Zn in orthogonal design was investigated by sequential extraction, and operationally defined as water-soluble and exchangeable(SE), weakly specific adsorbed(WSA), Fe and Mn oxides-bound(OX) and organic-bound(ORG). The results showed that fractions of heavy metals in the soil subsamples depended on their speciation. About 90% of Cd and 75% of Zn existed in soil subsamples in the SE fraction. Lead and Cu existed in soil subsamples as SE, WSA and OX fractions simultaneously, although SE was still the major fraction. Organic-bound heavy metals were not clearly apparent in all the soil subsamples. The concentration of some heavy metal fractions in soil subsamples showed the good correlation with ionic impulsion of soil, especially for the SE fraction. Continuous saturation of soil subsamples with 0.20 mol/L NH4Cl, which is the first step for determination of the negative surface charge of soil by the ion retention method, resulted in desorption of certain heavy metals from the soil. It was found that the percentage desorption of heavy metals from soil subsamples depended greatly on pH, the composition and original heavy metal content of the soil subsamples. However, most of the heavy metals in the soil subsamples were still be retained after multiple saturation. Compared with the parent soil, the negative surface charge of soil subsamples loaded with heavy metals did not show difference significantly from that of the parent one by statistical analysis. Heavy metals existed in the soil subsamples mainly as exchangeable and precipitated simultaneously.
Assuntos
Metais Pesados/química , Poluentes do Solo/análise , Cloreto de Amônio/química , Eletroquímica , Metais Pesados/isolamento & purificação , Propriedades de SuperfícieRESUMO
Toxicity assessment of Zn-Co mixtures involves multiple ions interactions. The negative potential (ψ0) at the cell membrane surface (CMs) concentrated cationic toxicants (denoted {M(2+)}0) and influenced the rhizotoxicity of Co(2+) or Zn(2+). The single and joint rhizotoxicity of Co(2+) and Zn(2+) to wheat (Triticum aestivum L.) were examined, coupled with different Ca(2+) levels. Joint effects of Zn(2+), Co(2+) and Ca(2+) were estimated by the linearly extended concentration addition (CA) and response addition (RA) models. Incorporation of Ca(2+) in single metal toxicity assessment significantly enhanced the prediction accuracy (r(2) increased from 0.948 to 0.550 for Zn(2+) and from 0.903 to 0.611 for Co(2+), respectively). ψ0 affected the multiple metals toxicity in both conventional mixture models (r(2)=0.814 for CA model and 0.820 for RA model). Concretely, {Zn(2+)}0 alleviated the toxicity of {Co(2+)}0, while {Co(2+)}0 had non-significant effect on {Zn(2+)}0 toxicity. Growth responses to {Ca(2+)}0 were substantially affected by {Zn(2+)}0 and {Co(2+)}0. Ca addition in medium decreased the {M(2+)}0 by reducing the ψ0 negativity, moreover this addition alleviated Ca deficiency at CMs induced by Zn(2+) (or Co(2+)). These consistent results from both extended CA and RA models indicated that ψ0 provided a novel sight for understanding the rhizotoxicity of multiple metals.
Assuntos
Cálcio/deficiência , Membrana Celular/efeitos dos fármacos , Cobalto/toxicidade , Raízes de Plantas/efeitos dos fármacos , Triticum/efeitos dos fármacos , Zinco/toxicidade , Cálcio/farmacologia , Relação Dose-Resposta a Droga , Interações Medicamentosas , Potenciais da Membrana/efeitos dos fármacos , Modelos Teóricos , Raízes de Plantas/crescimento & desenvolvimento , Triticum/citologia , Triticum/crescimento & desenvolvimentoRESUMO
Hydroxyapatite nanoparticle (nHAP) is increasingly being used to remediate soils and water polluted by metals and radionuclides. The transport and retention of Alizarin red S (ARS)-labeled nHAP were investigated in water-saturated granular media. Experiments were carried out over a range of ionic strength (I(c), 0-50mM NaCl) conditions in the presence of 10 mg L(-1) humic acid. The transport of ARS-nHAP was found to decrease with increasing suspension I(c) in part, because of enhanced aggregation and chemical heterogeneity. The retention profiles (RPs) of ARS-nHAP exhibited hyperexponential shapes (a decreasing rate of retention with increasing transport distance) for all test conditions, suggesting that some of the attachment was occurring under unfavorable conditions. Surface charge heterogeneities on the collector surfaces and especially within the ARS-nHAP population were contributing causes for the hyperexponential RPs. Consideration of the effect(s) of I(c) in the presence of HA is needed to improve the efficacy of nHAP for scavenging metals and actinides in real soils and groundwater environments.
Assuntos
Antraquinonas/química , Corantes/química , Durapatita/química , Nanopartículas/química , Poluentes do Solo/química , Poluentes Químicos da Água/química , Substâncias Húmicas , Concentração Osmolar , Dióxido de Silício/química , Propriedades de SuperfícieRESUMO
Soil heavy metal pollution resulting from human activities is causing major concern due to its potential risk. In this study, four crop species with different cultivars were planted in 2 levels (heavily and slightly) of heavy metal contaminated soils, and the accumulation of Cu, Zn, Pb, and Cd in the edible parts of the crops were investigated. Metal concentrations in sesame seeds grown in both soils exceeded both the Chinese Food Hygiene Standard (CFHS) and Codex Alimentarius Commission Standard (CACS), while the metal concentrations in all pepper cultivars in the slightly contaminated soil were below the CFHS and CACS. Other crops were generally in between in both soils. Among the tested crops, the order of soil-plant transfer factor (TF) was: sesame > green soybean > cowpea > pepper. Additionally, old fruit of cowpea contained larger amounts of metals than young fruit. It suggests that sesame should not be planted in the metal contaminated area, while pepper cultivar "Chaobianjiao No.1" may be an alternative to be grown in the slightly contaminated soil. There were differences in individual human susceptibilities to metals. Therefore, a comprehensive risk assessment should consider the frequency, amount and species consumed by human besides metal concentrations in crops.
Assuntos
Capsicum/metabolismo , Fabaceae/metabolismo , Glycine max/metabolismo , Metais Pesados/metabolismo , Sesamum/metabolismo , Transporte Biológico , Biomassa , Cádmio/análise , Cádmio/metabolismo , Capsicum/efeitos dos fármacos , Capsicum/crescimento & desenvolvimento , Cobre/análise , Cobre/metabolismo , Cobre/farmacologia , Produtos Agrícolas , Fabaceae/efeitos dos fármacos , Fabaceae/crescimento & desenvolvimento , Frutas/efeitos dos fármacos , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Humanos , Chumbo/análise , Chumbo/metabolismo , Chumbo/farmacologia , Metais Pesados/análise , Metais Pesados/farmacologia , Medição de Risco , Sesamum/efeitos dos fármacos , Sesamum/crescimento & desenvolvimento , Solo/análise , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Glycine max/efeitos dos fármacos , Glycine max/crescimento & desenvolvimento , Fatores de Tempo , Zinco/análise , Zinco/metabolismo , Zinco/farmacologiaRESUMO
In a pot experiment, pig manure (PM) and chicken manure (CM) were applied to an acidic soil at application rates of 2%, 4% and 8% (W/W) to evaluate their effects on the growth, Cu and Zn uptake and transfer of five cultivars of pakchoi (Brassica chinesis L.). The results showed that alkaline manures significantly increased the biomass of pakchois, and also pH and electrical conductivity of the soil. Both 0.01 M CaCl2 and 1.0 M NH4NO3 salt solutions predict the Zn transfer from soil to pakchois well, but not for Cu. For the cultivar Siyueman, the transfer factors of Cu (or Zn) in the PM treatments were higher than that in the CM treatments. In our experiment the Cu and Zn concentrations in pakchois did not exceed the Chinese Food Hygiene Standard, but more attention should be paid to heavy metals risk on pakchois at lower soil pH and salt impairment by manures application.