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Xu N, Zhu Q, Zhu J, Jia J, Wei X, Wang Y. Novel Latex Microsphere Immunochromatographic Assay for Rapid Detection of Cadmium Ion in Asparagus. Foods 2021; 11:foods11010078. [PMID: 35010203 PMCID: PMC8750861 DOI: 10.3390/foods11010078] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 12/09/2021] [Accepted: 12/20/2021] [Indexed: 12/25/2022] Open
Abstract
Recently, concerns about heavy metal cadmium ion (Cd2+) residue in asparagus have been frequently reported, and there is an urgent need to develop an effective, sensitive, and rapid detection method for Cd2+. In this study, we innovatively combined molecular microbiology to carry out the comparative screening of Cd2+ chelators in a green, efficient, and specific way. The knock-out putative copper-transporter gene (pca1Δ) yeast strain with high sensitivity to Cd2+ was first used to screen the Cd2+ chelator, and the optimum chelator 1-(4-Isothiocyanatobenzyl)ethylenediamine-N,N,N,N′-tetraacetic acid (ITCBE) was obtained. Additionally, a rapid latex microsphere immunochromatographic assay (LMIA) was developed, based on the obtained monoclonal antibody (mAb) with high specificity and high affinity (affinity constant Ka = 1.83 × 1010 L/mol), to detect Cd2+ in asparagus. The 50% inhibitive concentration (IC50) of test strip was measured to be 0.2 ng/mL, and the limit of detection (IC10) for qualitative (LOD, for visual observation) and quantitative detection (LOQ, for data simulation) of the test strip was 2 ng/mL and 0.054 ng/mL, respectively. In all, the developed mAb-based LMIA shows a great potential for monitoring Cd2+ in asparagus, even in vegetable samples.
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Affiliation(s)
- Naifeng Xu
- Institute of Engineering Food, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Xuhui District, Shanghai 200234, China; (N.X.); (Q.Z.); (J.Z.); (J.J.)
| | - Qiaojuan Zhu
- Institute of Engineering Food, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Xuhui District, Shanghai 200234, China; (N.X.); (Q.Z.); (J.Z.); (J.J.)
| | - Jiangxiong Zhu
- Institute of Engineering Food, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Xuhui District, Shanghai 200234, China; (N.X.); (Q.Z.); (J.Z.); (J.J.)
| | - Jingze Jia
- Institute of Engineering Food, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Xuhui District, Shanghai 200234, China; (N.X.); (Q.Z.); (J.Z.); (J.J.)
| | - Xinlin Wei
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, China
- Correspondence: (X.W.); (Y.W.); Tel.: +86-021-3420-8533 (X.W.); +86-186-1618-4495 (Y.W.)
| | - Yuanfeng Wang
- Institute of Engineering Food, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Xuhui District, Shanghai 200234, China; (N.X.); (Q.Z.); (J.Z.); (J.J.)
- Correspondence: (X.W.); (Y.W.); Tel.: +86-021-3420-8533 (X.W.); +86-186-1618-4495 (Y.W.)
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Identification and functional analysis of cadmium-binding protein in the visceral mass of Crassostrea gigas. Sci Rep 2021; 11:11306. [PMID: 34050239 PMCID: PMC8163822 DOI: 10.1038/s41598-021-90882-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 05/18/2021] [Indexed: 02/05/2023] Open
Abstract
The Pacific oyster, Crassostrea gigas, is a traditional food worldwide. The soft body of the oyster can easily accumulate heavy metals such as cadmium (Cd). To clarify the molecular mechanism of Cd accumulation in the viscera of C. gigas, we identified Cd-binding proteins. 5,10,15,20-Tetraphenyl-21H,23H-porphinetetrasulfonic acid, disulfuric acid, tetrahydrate, and Cd-binding competition experiments using immobilized metal ion affinity chromatography revealed the binding of water-soluble high molecular weight proteins to Cd, including C. gigas protein disulfide isomerase (cgPDI). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses revealed two CGHC motifs in cgPDI. The binding between Cd and rcgPDI was confirmed through a Cd-binding experiment using the TPPS method. Isothermal titration calorimetry (ITC) revealed the binding of two Cd ions to one molecule of rcgPDI. Circular dichroism (CD) spectrum and tryptophan fluorescence analyses demonstrated that the rcgPDI bound to Cd. The binding markedly changed the two-dimensional or three-dimensional structures. The activity of rcgPDI measured by a PDI Activity Assay Kit was more affected by the addition of Cd than by human PDI. Immunological analyses indicated that C. gigas contained cgPDI at a concentration of 1.0 nmol/g (viscera wet weight). The combination of ITC and quantification results revealed that Cd-binding to cgPDI accounted for 20% of the total bound Cd in the visceral mass. The findings provide new insights into the defense mechanisms of invertebrates against Cd.
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