1
|
Pinheiro BS, Moreira AJ, Gimenes LLS, Freschi CD, Freschi GPG. UV photochemical hydride generation using ZnO nanoparticles for arsenic speciation in waters, sediments, and soils samples. ENVIRONMENTAL MONITORING AND ASSESSMENT 2020; 192:331. [PMID: 32377885 DOI: 10.1007/s10661-020-08316-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
The environmental disasters that occurred due to the leakage of mining waste in Mariana-MG (2015) and Brumadinho-MG (2019), located in Brazil, attracted the attention of the scientific community. This designated efforts to investigate the environmental consequences of toxic waste in the affected ecosystem. Therefore, a simple, easily executed and accessible method was presented for arsenic speciation [As(III), As(V), and DMA]. Using an atomic absorption spectrometer coupled to the hydride generation system, the heterogeneous photocatalysis was applied in the reduction of As(V) and DMA to As(III). After the optimization, a calibration curve was constructed, with LODs equivalent to 3.20 μg L-1 As(III), 3.86 μg L-1 As(V), and 6.68 μg L-1 DMA. When applying the method for quantification in environmental samples, a concentration of up to 103.1 ± 9.4 μg L-1 As(V) was determined for surface water samples. The soil samples, 84.1 ± 3.6 μg L-1 As(III) and 112.4 ± 9.9 μg L-1 As(V) were quantified, proving the contamination of the ecosystems impacted by the environmental disasters. We proceeded the study through an addition/recovery method with samples of water, soil, and sediments (collected from impacted environments). Recovery values were equivalent to 99.0% for As(III), 93.8% for As(V), and 99.2% for DMA. Graphical abstract Photocatalytic reduction mechanism of As(V) and DMA to As(III) by heterogeneous photocatalysis.
Collapse
Affiliation(s)
- Bianca Santos Pinheiro
- Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil
| | - Ailton José Moreira
- Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil.
- Chemistry Department, Universidade Federal de São Carlos, São Carlos, SP, Brazil.
| | - Luana Lorca Sartori Gimenes
- Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil
| | - Carolina Dakuzaku Freschi
- Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil
| | - Gian Paulo Giovanni Freschi
- Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil
| |
Collapse
|
2
|
Lee SJC, Choi TS, Lee JW, Lee HJ, Mun DG, Akashi S, Lee SW, Lim MH, Kim HI. Structure and assembly mechanisms of toxic human islet amyloid polypeptide oligomers associated with copper. Chem Sci 2016; 7:5398-5406. [PMID: 30155193 PMCID: PMC6020819 DOI: 10.1039/c6sc00153j] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 04/18/2016] [Indexed: 12/14/2022] Open
Abstract
The molecular interaction of hIAPP with Cu(ii) mediates the formation of off-pathway and toxic oligomers which have small-sized and random coil structures.
Amyloidosis is a clinical disorder implicated with the formation of toxic amyloid aggregates. Despite their pathological significance, it is challenging to define the structural characteristics of amyloid oligomers owing to their metastable nature. Herein, we report structural and mechanistic investigations of human islet amyloid polypeptide (hIAPP) oligomers, found in type II diabetes mellitus, in both the absence and presence of disease-relevant metal ions [i.e., Cu(ii) and Zn(ii)]. These metal ions show suppressive effects on hIAPP fibrillation and facilitate the generation of toxic oligomers. Using circular dichroism spectroscopy, transmission electron microscopy, gel electrophoresis, small-angle X-ray scattering, and ion mobility-mass spectrometry, we investigated the assembly mechanisms of hIAPP oligomers in the presence and absence of metal ions. Oligomerization of both metal-free hIAPP and metal-associated hIAPP monomers is initiated following a similar growth model. However, in the presence of Cu(ii), hIAPP monomers self-assemble into small globular aggregates (Rg ∼ 45 Å) with a random coil structure. This Cu(ii)-associated hIAPP oligomer shows an off-pathway aggregation, and is suggested to be an end product which is toxic to pancreatic β-cells. On the other hand, metal-free hIAPP and Zn(ii)-associated hIAPP monomers generate relatively less toxic aggregates that eventually grow into fibrils. We suggest that the coordination of hIAPP to Cu(ii) and the relatively high stability (Ka, ca. 108 M–1) of hIAPP–Cu(ii) complexes result in the abnormal conformation and toxicity of hIAPP oligomers. Overall, through combining multiple biophysical methods, our studies suggest that molecular interactions between hIAPP and Cu(ii) induce a different pathway for hIAPP assembly. This work will advance our knowledge of the conformational basis, assembly mechanism, and toxicity of small soluble amyloid oligomers.
Collapse
Affiliation(s)
- Shin Jung C Lee
- Department of Chemistry , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919 , Republic of Korea . .,Department of Chemistry , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Republic of Korea
| | - Tae Su Choi
- Department of Chemistry , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Republic of Korea.,Department of Chemistry , Research Institute for Natural Sciences , Korea University , Seoul 02841 , Republic of Korea .
| | - Jong Wha Lee
- Department of Chemistry , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Republic of Korea.,Department of Chemistry , Research Institute for Natural Sciences , Korea University , Seoul 02841 , Republic of Korea .
| | - Hyuck Jin Lee
- Department of Chemistry , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919 , Republic of Korea .
| | - Dong-Gi Mun
- Department of Chemistry , Research Institute for Natural Sciences , Korea University , Seoul 02841 , Republic of Korea .
| | - Satoko Akashi
- Graduate School of Medical Life Science , Yokohama City University , Yokohama , Kanagawa 230-0045 , Japan
| | - Sang-Won Lee
- Department of Chemistry , Research Institute for Natural Sciences , Korea University , Seoul 02841 , Republic of Korea .
| | - Mi Hee Lim
- Department of Chemistry , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919 , Republic of Korea .
| | - Hugh I Kim
- Department of Chemistry , Research Institute for Natural Sciences , Korea University , Seoul 02841 , Republic of Korea .
| |
Collapse
|