The ADAM (a disintegrin and metalloprotease) protein family uniquely exhibits both catalytic and adhesive properties. In the well-defined process of ectodomain shedding, ADAMs transform latent, ...cell-bound substrates into soluble, biologically active derivatives to regulate a spectrum of normal and pathological processes. In contrast, the integrin ligand properties of ADAMs are not fully understood. Emerging models posit that ADAM-integrin interactions regulate shedding activity by localizing or sequestering the ADAM sheddase. Interestingly, 8 of the 21 human ADAMs are predicted to be catalytically inactive. Unlike their catalytically active counterparts, integrin recognition of these "dead" enzymes has not been largely reported. The present study delineates the integrin ligand properties of a group of non-catalytic ADAMs. Here we report that human ADAM11, ADAM23, and ADAM29 selectively support integrin alpha4-dependent cell adhesion. This is the first demonstration that the disintegrin-like domains of multiple catalytically inactive ADAMs are ligands for a select subset of integrin receptors that also recognize catalytically active ADAMs.
•The Cu(II)–EDTA removal by NNN-SBA-15 from dilute solution was effective.•The sorption can reach equilibrium within 2min.•Coexistence of EDTA species increased the capture ability of copper.•XPS ...results showed that electrostatic interaction was the main sorption mechanism.
The preparation and application of tri-ammonium-functionalized mesoporous silica SBA-15 (NNN-SBA-15) for sequestering Cu(II)–EDTA chelates from aqueous solution with low concentration of 0.1mmol/L were explored. The adsorption properties of copper in the presence of equimolar EDTA were examined as a function of initial pH, ionic strength, initial concentration and temperature. Results revealed that the adsorption of Cu(II)–EDTA chelates on NNN-SBA-15 achieved equilibrium within 2min and fitted well with the Langmuir model. The maximum copper adsorption capacity was estimated to be 26.3mg/g. High ionic strength (0.1mol/L of NaNO3) influenced the removal of Cu(II)–EDTA chelates, while temperature (from 15 to 35°C) had slight effect on the adsorption capacity. Compared with the copper sorption system without EDTA species, the capture ability of copper increased significantly with coexistence of EDTA species in acidic condition. XPS spectrum studies indicated that Cu(II)–EDTA was removed from aqueous solution by the electrostatic interaction and hydrogen bond interaction between the protonated amine groups of NNN-SBA-15 and Cu(II)-EDTA chelates.
► Biogeochemical behavior of Pb strongly depends on its chemical speciation. ► Organic ligands modify Pb speciation and in turns, its biogeochemical behavior. ► Effect of organic ligand on Pb ...behavior vary with soil characteristics. ► Efficiency of organic ligands to modify Pb behavior vary with their binding capacity.
Biogeochemical behavior of lead (Pb), a persistent hazardous pollutant of environmental concern, strongly depends on its chemical speciation. Therefore, in this review, link between Pb speciation: presence of organic ligands and its environmental behavior has been developed. Both, biogeochemical and ecotoxicological data are discussed in environmental risk assessment context and phytoremediation studies. Three kinds of organic ligands selected for this review include: (1) ethylene diamine tetra-acetic acid (EDTA), (2) low molecular weight organic acids (LMWOAs) and (3) humic substances (HSs). The review highlights the effect of Pb speciation on: (i) Pb fate and behavior in soil; (ii) Pb plant uptake and accumulation in different plant parts; and (iii) Pb-induced phyto-toxicity. Effects of organic ligands on Pb speciation are compared: how they can change Pb speciation modifying accordingly its fate and biogeochemistry in soil-plant system? EDTA forms soluble, stable and phytoavailable Pb-chelates due to high binding Pb affinity. LMWOAs can solubilize Pb in soil by decreasing soil pH or increasing soil organic contents, but have little effect on its translocation. Due to heterogeneous structure, HSs role is complex. In consequence Pb speciation knowledge is needed to discuss phyto-toxicity data and improved soil phytoremediation techniques.
•A new removal process for NO is proposed and investigated.•Effects of several key parameters on the removal process are studied.•Existing and newly proposed reaction pathways of NO removal are ...discussed.•The advantages and/or merits of this new process are also discussed.
Nitric oxide (NO) removal from simulated flue gas is investigated using combined aqueous persulfate (Na2S2O8) and ferrous ethylenediaminetetraacetate (Fe2+–EDTA) systems. The results at 23–70°C showed significant improvement in NO removal using the optimally obtained molar ratio of 1:1 for the Fe2+ and EDTA compared with temperature-only and combined temperature-Fe2+ activated persulfate systems with 0.1M Na2S2O8 and 0.01M Fe2+ in the absence of EDTA. Almost 100% NO conversion can be achieved at 70°C (flue gas treatment inlet temperature generally at 50–70°C) compared to temperature and Fe2+-activated persulfate systems which require ⩾90°C for such high removal efficiency. The percentage increases in NO removal were dependent on temperature, 25–30% and 5–10% at the lower (<40°C) and higher (>40°C) temperatures, respectively. A very high concentration of Fe2+–EDTA appears to negatively impact NO removal. However, this process operates at an optimal NO removal pH of near neutral (∼6.5) with efficiency decreasing at very low or high pH. This should reduce the use of auxiliary chemical for pH adjustment and help mitigate the important technological hurdle of undesired ferric product formation associated with Fe2+-only activated persulfate and other Fenton-like systems at pH (>3.5). The material balance on iron species (Fe2+, Fe3+ and Fe2+–EDTA) was determined to better understand the chemistry of persulfate with Fe2+–EDTA for NO removal. The results demonstrate the feasibility of near complete NO removal at relatively lower temperatures (with the advantage of reduced energy usage), and sustained longtime high NO absorption capability.
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•EDTA grafted silica was prepared and used as an adsorbent for Cu(II), Zn(II) and NI(II).•Adsorption of heavy metals followed pseudo-second order kinetics and Langmuir ...isotherm.•Intra-particle diffusion mechanism was involved in the removal of heavy metals.•Adsorption process was spontaneous and endothermic in nature.
Ethylenediaminetetraacetic acid (EDTA) functionalized silica adsorbent has been synthesized using (3-aminopropyl) triethoxylsilane (APTES) as a bridging link between silanol groups (SiOH) of silica and carboxylic group of EDTA. Fourier transform infrared spectroscopy (FTIR) and Temperature-programmed oxidation (TPO) analysis confirmed the grafting of EDTA onto the silica. The synthesized EDTA–silica was investigated as an adsorbent for removal of Cu(II), Zn(II) and Ni(II) from aqueous solution. The effect of solution pH, initial solution concentration, and contact time were studied. The removal of metal ions increased with the increase in solution pH, contact time and concentration. The maximum equilibrium time was found to be 45min for all three metal ions. Kinetics studies revealed that the adsorption of Cu(II), Zn(II) and Ni(II) onto EDTA–silica followed the pseudo-second order kinetics and film diffusion and intra-particle diffusion mechanism were involved. Adsorption equilibrium data were well fitted to Langmuir isotherm model and maximum monolayer adsorption capacity for Cu(II), Zn(II) and Ni(II) was 79.36, 74.07 and 67.56mgg−1, respectively. Thermodynamic results reveal that the removal of metals onto EDTA–silica was endothermic and spontaneous in nature.
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•EDTA-based adsorbents for the removal of metal ions are reviewed for the first time.•The adsorption thermodynamics, isotherm model, and kinetics model are discussed.•Their ...applications and regeneration are introduced in this review.
Ethylene diamine tetraacetic acid (EDTA) is an excellent chelating agent. Its two amino groups and four carboxyl groups can be used as the binding sites of metal ions. EDTA can form stable water-soluble chelates with almost all transition metal ions. Meanwhile, EDTA is grafted onto the adsorbents through physical or chemical modification to improve the performance of the adsorbents. Therefore, EDTA-based adsorbents for the removal of metal ions in wastewater have attracted extensive attention in recent years. This article reviews the advantages and disadvantages of different types of EDTA-based adsorbents from the aspects of preparation, adsorption capacity, adsorption rate, adsorption mechanism, and regeneration. In addition, the potential applications and limitations of EDTA-based adsorbents are summarized. Finally, the challenges and future development directions of EDTA-based adsorbents are prospected.
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•Ag-Co nanoparticles with rich catalytic sites are effectively decorated on Fe3O4@EDTA by co-reducing agent in-situ deposition method for the first time.•The Ag-Co@EDTA@Fe3O4 NPs ...expressed high saturation magnetization.•The enhanced catalytic activity of Ag-Co@EDTA@Fe3O4 NPs towards 2-nitrophenol reduction was explored.•The hydrodynamic diameter of Ag-Co@EDTA@Fe3O4 NPs was unobviously increased after 5 cycle times.
In this study, firstly, bimetallic Ag-Co nanoparticles with rich catalytic sites decorated on Fe3O4 magnetic carriers through metal ion chelating agent EDTA (Ag-Co@EDTA@Fe3O4 NPs) were fabricated by co-reducing agent in-situ deposition method for the first time. The synthesized nanocomposites were characterized by various techniques, including UV–vis, XRD, TEM, EDX, XPS and VSM. Secondly, the catalytic reduction performance of Ag-Co@EDTA@Fe3O4 NPs was analyzed for 2-nitrophenol in the presence of NaBH4 at 25 ℃. Results showed that the k of Ag-Co@EDTA@Fe3O4 NPs was 10.9 and 2.7 times higher than that of Co@EDTA@Fe3O4 and Ag@EDTA@Fe3O4 NPs, respectively, which considered to obey the first-order kinetics equation, proving the strong synergistic effect between Ag and Co nanoparticles. Furthermore, the significantly enhanced catalytic activity of Ag-Co@EDTA@Fe3O4 NPs was discussed. Plenty of Ag NPs were successfully anchored on Fe3O4@EDTA supports maybe the crucial factor, and the doped Co provided much more active sites in the catalytic process. Finally, the degradation efficiency of Ag-Co@EDTA@Fe3O4 NPs still remained above 95% after 5 cycles. Importantly, there was no significant difference between the fresh catalyst and after cycling for 5 times, observed by TEM and SEM. Meanwhile, the change of hydrodynamic diameter of the used Ag-Co@EDTA@Fe3O4 NPs over cycle number was measured around 230 nm which increased unobviously, making it a promising candidate for wastewater treatment in industries.
•A combinative strategy involving TiCl3 coagulation and microfiltration membrane was firstly applied to remove Ni-EDTA.•Ni2+ and TOC removal efficiency in the combinative process was achieved to 97 % ...and 93 % in synthetic electroplating wastewater, respectively.•The released Ni2+ was reduced to Ni0 by Ti3+ and the dissociated EDTA would combine with oxidized Ti4+ to form Ti-EDTA.•The transformants after reaction were insoluble, precipitable, and easy to be separated via microfiltration.
Ni-EDTA is a common heavy metal complex found in electroplating wastewater. As heavy metal complexes are stable and highly toxic, it is essential to develop efficient strategies to remove. In this work, TiCl3 coagulation and ceramic microfiltration membrane were combined in the removal of Ni-EDTA. Based on the results, this combinative process exhibited a high Ni-EDTA removal efficiency. When compared to employing the TiCl3 coagulation process only, the combinative process improved Ni2+ and TOC removal efficiencies from 91 % to 97 % and from 60 % to 93 %, respectively. Furthermore, it was found that the in-situ formed titanium hydrolysates possessed good adsorption for EDTA and Ni-EDTA, with maximum capacities reaching 713 mg/g and 213 mg/g, respectively, which also enabled the cake layer a considerable secondary removal for TOC. Mechanistic investigations confirmed that the reducibility of Ti3+ contributed to both Ni-EDTA and EDTA removal. In the presence of Ti3+, Ni-EDTA was decomplexed and the released Ni2+ was reduced to Ni0 synchronously. Meanwhile, some dissociated EDTA would combine with oxidized Ti4+ to form Ti-EDTA and ultimately promote the formation of TiO2 crystals. The formation of the insoluble chelate Ti-EDTA and the adsorption by surface hydroxyl of TiO2 were the key reasons for the efficient removal for released EDTA. This work provides a new approach for the decomplexation and harmless separation of heavy metal complexes.
Porcine reproductive and respiratory syndrome (PRRS) caused by PRRS virus (PRRSV) is one of the most severe swine diseases that affects almost all swine-breeding countries. Nonstructural protein 2 ...(NSP2) is one of the most important viral proteins in the PRRSV life cycle. Our previous study showed that PRRSV NSP2 could induce the formation of aggresomes. In this study we explored the effects of aggresome formation on cells and found that NSP2 could induce autophagy, which depended on aggresome formation to activate aggrephagy. The transmembrane and tail domains of NSP2 contributed to aggrephagy and the cellular protein 14-3-3epsilon played an important role in NSP2-induced autophagy by binding the tail domain of NSP2. These findings provide information on the function of the C-terminal domain of NSP2, which will help uncover the function of NSP2 during PRRSV infection. Keywords: PRRSV, NSP2, Aggrephagy, 14-3-3epsilon, Tail domain of NSP2
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