Amyloid peptide fibrillogenesis induced by Cu（II） ions is a key event in the pathogenesis of Alzheimer＇s disease. Dendrimers have been found to be active in preventing fibril formation. Therefore, they hold promise...Amyloid peptide fibrillogenesis induced by Cu（II） ions is a key event in the pathogenesis of Alzheimer＇s disease. Dendrimers have been found to be active in preventing fibril formation. Therefore, they hold promise for the treatment of Alzheimer＇s disease. In this study, the fibrillation mechanism of amyloid peptide Aβ 1-40 was studied by adding Cu（II） in the absence and presence of 4th generation poly（propyleneimine） glycodendrimer functionalized with sulfate groups, using dynamic light scattering （DLS）, circular dichroism （CD）, fluorescence, electron paramagnetic resonance （EPR） and molecular modeling （MD）. The glycodendrimer was non-toxic to mHippoE-18 embryonic mouse hippocampal cells, selected as a nerve cell model and decreased the toxicity of peptide aggregates formed after the addition of Cu（II）. The binary systems of Cu（II）-glycodendrimer, Cu（II）-peptide, and glycodendrimer-peptide were first characterized. At the lowest Cu（II）/glycodendrimer molar ratios, Cu（II） was complexed by the internal-dendrimer nitrogen sites. After saturation of these sites, Cu（II） binding with sulfate groups occurred. Stable Cu（II）-peptide complexes formed within 5 min and were responsible for a transition from an α helix to a β-sheet conformation of Aβ 1-40. Glycodendrimer-peptide interactions provoked the stabilization of the a-helix, as demonstrated in the absence of Cu（II） by the Thioflavin T assay, and in the presence of Cu（II） by CD, EPR, and MD. Formation of fibrils is differentially modulated by glycodendrimer and Cu（II） concentrations for a fixed amount of Aβ 1-40. Therefore, this multidisciplinary study facilitated the recognition of optimal experimental conditions that allow the glycodendrimer to avoid the fibril formation induced by Cu（II）.展开更多
In recent years,the surge in industrialization and urbanization has led to the release of a significant amount of heavy metal ions into water.These ions,when present in drinking water,can enter the human body and caus...In recent years,the surge in industrialization and urbanization has led to the release of a significant amount of heavy metal ions into water.These ions,when present in drinking water,can enter the human body and cause irreversible health problem.Metal-organic frameworks (MOFs) have drawn considerable attention for their outstanding ability to remove these heavy metal ions.However,MOF powders tend to aggregate in water,reducing their adsorption efficiency and potentially leading to secondary environmental pollution.In this regard,the development of MOF composites that are highly adsorptive,recyclable,and maintain stable dispensability in water is crucial for heavy metal ions removal.Herein,the in situ growth of zeolitic imidazolate framework (ZIF-8) on melamine sponge (MS) using a secondary growth method is reported.The resultant composite sponges exhibit high efficiency in adsorbing Pb(II);Cu(II) from water and maintain good reusability.These findings offer a promising method in efficiently eliminating Pb(II);Cu(II) from aqueous solutions.展开更多
Four μ-oxamido heterodinuclear complexes, [Cu(oxae)Cr(L)2] (NO3)3,where oxae denotes the N, N’-bis (2-aminoethyl) oxamido dianion and L represents 1, 10-phenanthroline ( phen); 5-nitro-1, 10-phenanthroline (NO2-phen...Four μ-oxamido heterodinuclear complexes, [Cu(oxae)Cr(L)2] (NO3)3,where oxae denotes the N, N’-bis (2-aminoethyl) oxamido dianion and L represents 1, 10-phenanthroline ( phen); 5-nitro-1, 10-phenanthroline (NO2-phen); 5-methyl-1, 10-phenanthroline (Me-phen) and 2,2’-bipyridine (bpy), have been synthesized and characterized by elemental analyses, magnetic moments (at room temperature) and molar conductivity measurements and spectroscopy. It is proposed that these complexes have extended oxamido-bridged structures consisting of a copper (Ⅱ) ion and a chromium (Ⅲ) ion, which have a square planar environment and octahedral environment, respectively. The cryomagnetic properties of the [Cu(oxae)Cr(bpy)2] (NO3)3(1) and [Cu(oxae)Cr(phen)2] (NO3)3(2) complexes have been measured over the range of 4.2-300 K. The least-squares fit of the experimental data based on the spin Hamiltonian, H = - 2JS1·S2, the exchange integrals (J) were evaluated as + 36.9 cm-1 for 1 and +35.8 cm-1 for 2. The results have confirmed展开更多
文摘Amyloid peptide fibrillogenesis induced by Cu（II） ions is a key event in the pathogenesis of Alzheimer＇s disease. Dendrimers have been found to be active in preventing fibril formation. Therefore, they hold promise for the treatment of Alzheimer＇s disease. In this study, the fibrillation mechanism of amyloid peptide Aβ 1-40 was studied by adding Cu（II） in the absence and presence of 4th generation poly（propyleneimine） glycodendrimer functionalized with sulfate groups, using dynamic light scattering （DLS）, circular dichroism （CD）, fluorescence, electron paramagnetic resonance （EPR） and molecular modeling （MD）. The glycodendrimer was non-toxic to mHippoE-18 embryonic mouse hippocampal cells, selected as a nerve cell model and decreased the toxicity of peptide aggregates formed after the addition of Cu（II）. The binary systems of Cu（II）-glycodendrimer, Cu（II）-peptide, and glycodendrimer-peptide were first characterized. At the lowest Cu（II）/glycodendrimer molar ratios, Cu（II） was complexed by the internal-dendrimer nitrogen sites. After saturation of these sites, Cu（II） binding with sulfate groups occurred. Stable Cu（II）-peptide complexes formed within 5 min and were responsible for a transition from an α helix to a β-sheet conformation of Aβ 1-40. Glycodendrimer-peptide interactions provoked the stabilization of the a-helix, as demonstrated in the absence of Cu（II） by the Thioflavin T assay, and in the presence of Cu（II） by CD, EPR, and MD. Formation of fibrils is differentially modulated by glycodendrimer and Cu（II） concentrations for a fixed amount of Aβ 1-40. Therefore, this multidisciplinary study facilitated the recognition of optimal experimental conditions that allow the glycodendrimer to avoid the fibril formation induced by Cu（II）.
基金supported by the Project of the Departments of Science and Technology of Jilin Province,China (Nos.20220101230JC,YDZJ202201ZYTS592).
文摘In recent years,the surge in industrialization and urbanization has led to the release of a significant amount of heavy metal ions into water.These ions,when present in drinking water,can enter the human body and cause irreversible health problem.Metal-organic frameworks (MOFs) have drawn considerable attention for their outstanding ability to remove these heavy metal ions.However,MOF powders tend to aggregate in water,reducing their adsorption efficiency and potentially leading to secondary environmental pollution.In this regard,the development of MOF composites that are highly adsorptive,recyclable,and maintain stable dispensability in water is crucial for heavy metal ions removal.Herein,the in situ growth of zeolitic imidazolate framework (ZIF-8) on melamine sponge (MS) using a secondary growth method is reported.The resultant composite sponges exhibit high efficiency in adsorbing Pb(II);Cu(II) from water and maintain good reusability.These findings offer a promising method in efficiently eliminating Pb(II);Cu(II) from aqueous solutions.
基金supported by the National Natural Science Foundation of China (21173135)Specialized Research Fund for the Doctoral Program of Higher Education of China (20110131130008)+1 种基金Taishan Scholar Foundation of Shandong Province, China (ts20070713)Graduate Independent Innovation Foundation of Shandong University, China (yzc10112)~~
基金Project supported by the Natural Science Foundation of Shandong Province of China (No. Y97-D17076, Q96B01115)the National Natural Science Foundation of China (No. 29631040).
文摘Four μ-oxamido heterodinuclear complexes, [Cu(oxae)Cr(L)2] (NO3)3,where oxae denotes the N, N’-bis (2-aminoethyl) oxamido dianion and L represents 1, 10-phenanthroline ( phen); 5-nitro-1, 10-phenanthroline (NO2-phen); 5-methyl-1, 10-phenanthroline (Me-phen) and 2,2’-bipyridine (bpy), have been synthesized and characterized by elemental analyses, magnetic moments (at room temperature) and molar conductivity measurements and spectroscopy. It is proposed that these complexes have extended oxamido-bridged structures consisting of a copper (Ⅱ) ion and a chromium (Ⅲ) ion, which have a square planar environment and octahedral environment, respectively. The cryomagnetic properties of the [Cu(oxae)Cr(bpy)2] (NO3)3(1) and [Cu(oxae)Cr(phen)2] (NO3)3(2) complexes have been measured over the range of 4.2-300 K. The least-squares fit of the experimental data based on the spin Hamiltonian, H = - 2JS1·S2, the exchange integrals (J) were evaluated as + 36.9 cm-1 for 1 and +35.8 cm-1 for 2. The results have confirmed
