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Zhong L.,Shanghai JiaoTong University | Zhong L.,Bor h Food Safety Research Center | Wang L.,Shanghai JiaoTong University | Wang L.,Key Laboratory of Urban Agriculture South of Ministry of Agriculture | And 20 more authors.
Environmental Toxicology and Pharmacology | Year: 2014

Trace amount zinc plays key roles in biological systems, while in excessive amount it causes toxic effects. Evidence shows that there exists a crosstalk between NO and Zn apoptotic signal transduction pathway. However, the potential mechanism of Zn-induced cellular responses through the NOS signaling pathway has not been determined yet. In this research, trace amount ZnCl2 (1nM) could induce the NO production, however it appears that this influence does not extend to genetic level in MCF-7 cells. Whereas, excess ZnCl2 (100μM, 1mM) could lead to a decreased NO production first with the release of Ca2+, and then induce the NO production with the transcriptional and translational activation of NOSs. The ROS generation was also induced by excess ZnCl2, causing the elF2α phosphorylation. The alleviation effect of N-acetyl-l-cysteine or l-arginine on the Zn-induced ROS generation and apoptosis suggested that Zn-induced apoptosis was associated with the NOS-mediated oxidative stress. © 2014 Elsevier B.V. Source


Zhong L.,Shanghai JiaoTong University | Zhong L.,Bor h Food Safety Research Center | Wang L.,Shanghai JiaoTong University | Wang L.,Bor h Food Safety Research Center | And 20 more authors.
BioMetals | Year: 2015

Copper (Cu) ion is essential for the biological systems, however, high level of CuCl2 exposure causes detrimental effects, which leads to cell apoptosis. Nitric oxide (NO) is an efficient cell signal messenger, which plays an important role in cell apoptosis. However, the potential mechanism of an early phase Cu-induced acute cytotoxicity through the nitric oxide synthase (NOS) signaling pathway and its interaction has not been studied. In this report, we provide data showing that high level of CuCl2 could rapidly decrease the NO production with the release of Ca2+ and Zn2+, and then modulate the transcriptional and translational expression of NOSs in MCF-7 cells. The reactive oxygen species (ROS) level in cells was increased after high level of CuCl2 exposure, which led to the alpha subunit of eukaryotic initiation factor 2 phosphorylation. By using the free radical scavenger N-acetyl-L-cysteine or the NOS substrate L-arginine, it demonstrated that NOS played a critical role on the Cu-induced ROS generation, which further led to the oxidative stress and cell apoptosis. These results suggested that Cu-induced apoptosis was associated with the oxidative stress, and through the NOS-mediated signaling pathway. © Springer Science+Business Media 2014. Source


He L.,Shanghai JiaoTong University | He L.,Key Laboratory of Urban Agriculture South of Ministry of Agriculture | He L.,Bor h Food Safety Research Center | Luo Y.,Shanghai JiaoTong University | And 8 more authors.
Food Analytical Methods | Year: 2013

We have developed an unlabeled sensing strategy for tetracycline (TET) detection in aqueous solutions and milk by using an aptamer-gold nanoparticle (AuNP)-based colorimetric method. Aptamers were found to be absorbed on the Au surface which stabilizes the AuNPs against conditions of high poly(diallyldimethylammonium) strength. The introduction of TET had reduced aptamers to form a TET-aptamer complex, so that the following cationic polymers could aggregate AuNPs and cause a remarkable change in color. Through this phenomenon, TET can be detected qualitatively and quantitatively by means of absorbance. This unlabeled strategy saves both the time and cost for detection, which could selectively detect TET at concentrations as low as 1 μM and 45.8 nM for the naked eyes and colorimetric detector, respectively. In addition, this biosensor exhibited high selectivity over other antibiotics with an excellent recovery in the detection of milk. Because of the advantages of this sensor, we hope this will be the basis for an assay for the sensitive, colorimetric detection of a wide range of molecular analytes. © 2013 Springer Science+Business Media New York. Source


Zhong L.,Shanghai JiaoTong University | Zhong L.,Bor h Food Safety Research Center | Wang L.,Shanghai JiaoTong University | Wang L.,Bor h Food Safety Research Center | And 20 more authors.
Environmental Toxicology | Year: 2016

The potential Pb-induced cytotoxicity in various tissues and biological systems has been reported. Some evidences also indicate that the Pb-caused cytotoxicity may be associated with the nitric oxide synthase (NOS). However, there remains uncertainty about the role of the NOS signaling pathway during the Pb-induced cytotoxicity. In this report, we provide data showing that PbCl2 treatment depresses the expressions of the three distinct NOS isoforms: neuronal nitric oxide synthase (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS) on both transcriptional and translational levels in MCF-7 cells. The down-regulation of NOSs expressions by PbCl2 exposure leads to reduced NOS activity and nitric oxide (NO) production. Meanwhile, the intracellular reactive oxygen species (ROS) level is elevated after PbCl2 exposure, which leads to the alpha subunit of eukaryotic initiation factor 2 (elF2α) phosphorylation. The reduction effects of the free radical scavenger N-acetyl-l-cysteine or the NOS substrate l-arginine on the Pb-induced ROS generation suggest that the NOS signaling pathway plays a key role in the Pb-induced oxidative stress, which further results in the elF2α phosphorylation and cytotoxicity. © 2016 Wiley Periodicals, Inc. Source

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