1.
Experimental and theoretical validations of a one-pot sequential sensing of Hg2+ and biothiols by a 3D Cu-based zwitterionic metal-organic framework.
Chen, HL, Li, RT, Wu, KY, Hu, PP, Zhang, Z, Huang, NH, Zhang, WH, Chen, JX
Talanta. 2020;:120596
Abstract
A zwitterionic three-dimensional (3D) metal-organic framework (MOF) of {[Cu(Cdcbp)(bipy)]·4H2O}n (1) has been synthesized and characterized (H3CdcbpBr = 3-carboxyl-(3,5-dicarboxybenzyl)-pyridinium bromide; bipy = 4,4'-bipyridine). MOF 1 exhibits a variety of structural traits, such as ligand conjugated, positively charged pyridinium center, and Cu(II) cations that collectively enable its efficient hybridization with the flexible, negatively charged, single-stranded, and thymine-rich (T-rich) DNA. The T-rich DNA is labeled with carboxyfluorescein (FAM) fluorescent probe (characterized as P-DNA), but the resultant MOF 1 - P-DNA hybrid (characterized as P-DNA@1) is non-emissive (off-state) because of the fluorescent quenching by MOF 1. The P-DNA@1 hybrid functions as an effective and selective sensor for Hg2+ due to the formation of rigid hairpin-like T-Hg2+-T double-stranded DNA (ds-DNA@Hg2+) which is subsequently ejected by MOF 1, triggering a recovery of the P-DNA fluorescence (on-state). Subsequent addition of biothiols further sequestrates Hg2+ from the ds-DNA@Hg2+ duplex driven by the stronger Hg-S coordination, thus release the P-DNA and, in turn, resorbed by MOF 1 to regain the initial hybrid (off-state). P-DNA@1 hybrid thus detects Hg2+ and biothiols sequentially via a fluorescence "off-on-off" mechanism. The limits of detection (LOD) for Hg2+, biothiols, including cysteine (Cys), glutathione (GSH) and homocysteine (Hcy) are 3.0, 14.2, 15.1 and 8.0 nM, respectively, with the detection time of 60 min for Hg2+, and instantaneous detection for all the three biothiols. The detection mechanism is further confirmed by circular dichroism (CD), fluorescence anisotropy (FA), binding constant and molecular simulation. This sequential detection of Hg2+ and biothiols counter-proofs the presence of each other and may shed light to the occurrence of related diseases, such as neurodegenerative disorders of Parkinson's disease (PD), and Alzheimer's disease (AD).
2.
[Effects of lead, copper and cadmium stresses on growth and inherent quality of Prunalla vulgaris].
Wu, Z, Guo, Q, Wang, Q, Zhou, L, Zhang, Z, Zhang, L, Huang, T
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica. 2010;(3):263-7
Abstract
OBJECTIVE Prunalla vulgaris was used as the experimental material to study the effects of lead (Pb), copper (Cu) and cadmium (Cd) on the related physiological and growth indexes of the plant. METHOD By referencing the GAP and the soil environmental quality standard, the growth and inherent quality of the plant were observed under different concentrations of the heavy metals stresses. The data were statistically processed. RESULT The results showed that the plant grew normally when the heavy metal concentrations in soil were close to up limits of the soil environmental quality standard II. The content of heavy metal in spica met the requirement of the standard, and under the circumstances the content of ursolic acid was increased in a certain range. The critical values of Pb, Cu, Cd in the P. vulgaris grown soil were set at 450, 100, 1.0 mg x kg(-1), respectively. CONCLUSION The harmful influence of the heavy metal stress at a lower concentration is lighter than at a higher concentration, and it could increase the content of ursolic acid. The stress of Pb, Cu and Cd is more obvious than that of Zn.