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1.
Wei de Zhang Fan Qing Li Xiao Yun Zhang Ying Chen 《Biological trace element research》1988,17(1):81-90
The growth of the protozoanBlepherisma is stimulated by Lanthanum (La) at concentrations as low as 0.32 ppm. In mice Yttrium (Y) and Ytterbium (Yb) are absorbed,
accumulated, and metabolized. Both rare earth elements (RE) exhibit a high affinity for teeth and bones, accumulation occurs
and metabolism is slow. In the livers of RE-exposed mice, concentrations are variable. The liver is apparently capable of
absorbing and discharging RE in a manner depending on metabolic activity. The main route of discharge for ingested REs is
the alimentary canal. Exposure of pregnant mice to RE leads to rapid placental transfer of RE; 14.1% of the total amount of
RE administered was detected in newborn mice. Young, developing organisms appear to be especially susceptible to RE accumulation. 相似文献
2.
3.
Asieh Moodi Meissam Noroozifar Sona Niroomand 《Journal of biomolecular structure & dynamics》2013,31(8):937-950
To evaluate the biological preference of [Yb(phen)2(OH2)Cl3](H2O)2 (phen is 1,10-phenanthroline) for DNA, interaction of Yb(III) complex with DNA in Tris–HCl buffer is studied by various biophysical and spectroscopic techniques which reveal that the complex binds to DNA. The results of fluorescence titration reveal that [Yb(phen)2(OH2)Cl3](H2O)2 has strongly quenched in the presence of DNA. The binding site number n, apparent binding constant K b, and the Stern–Volmer quenching constant K SV are determined. ΔH 0, ΔS 0, and ΔG 0 are obtained based on the quenching constants and thermodynamic theory (ΔH 0?>?0, ΔS 0?>?0, and ΔG 0?<?0). The experimental results show that the Yb(III) complex binds to DNA by non-intercalative mode. Groove binding is the preferred mode of interaction for [Yb(phen)2(OH2)Cl3](H2O)2 to DNA. The DNA cleavage results show that in the absence of any reducing agent, Yb(III) complex can cleave DNA. The antimicrobial screening tests are also recorded and give good results in the presence of Yb(III) complex. 相似文献
4.
Ernestas Gaidamauskas Kanokkarn Saejueng Alvin A. Holder Subalita Bharuah Boris A. Kashemirov Debbie C. Crans Charles E. McKenna 《Journal of biological inorganic chemistry》2008,13(8):1291-1299
Metal complexation reactions can be used effectively as sensors to measure concentrations of phosphate and phosphate analogs.
Recently, a method was described for the detection of phosphate or ATP in aqueous solution based on the displacement by these
ligands of pyrocatechol violet (PV) from a putative 2:1 (Yb3+)2PV complex. We have not been able to reproduce this stoichiometry and report this work in order to correct the coordination
chemistry upon which sensor applications are based. In our work, colorimetric and spectrophotometric detection of phosphate
was confirmed qualitatively (blue PV + Yb3+; yellow + Pi); however, the sequence of visual changes on the titration of PV with 2 equiv. of Yb3+ and back titration with ATP as described previously could not be reproduced. In contrast to the linear response to Pi that was reported previously, the absorbance response at 443 or 623 nm was found to be sigmoidal using the recommended 2:1
Yb3+:PV solution (100 μM:50 μM, pH 7, HEPES). Furthermore, both continuous variation titration and molar ratio analysis (Job plot)
experiments are consistent with 1:1, not 2:1, YbPV complex stoichiometry at pH 7 in HEPES buffer, indicating that the deviation
from linearity is produced by excess Yb3+. Indeed, using a 1:1 Yb3+:PV ratio produces a linear response in ΔAbs at 443 or 623 nm on back titration with analyte (phosphate or ATP). In addition,
speciation analysis of the Yb–ATP system demonstrates that a 1:1 complex containing Yb3+ and ATP predominates in solution at μM metal ion and ATP concentrations. Paramagnetic 1H NMR spectroscopy directly establishes the formation of Yb3+–solute complexes in dilute aqueous solution. The 1:1 YbPV complex can be used for the colorimetric measurement of phosphate
and ATP concentrations from ~2 μM.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Charles E. McKenna (Corresponding author)Email: |
5.
The synthesis and characterization of (TptBu,Me)Yb(BH4)(THF)n (n = 0, 3; n = 1, 4) complexes are reported. The compounds represent rare examples of lanthanide (II) tetrahydroborate complexes. The X-ray crystal structure of complex 4 has been determined and it shows a monomeric, formally seven coordinate ytterbium center, bearing one κ3 bonded TptBu,Me ligand, a tetrahydroborate ligand and a coordinated THF molecule. The tetrahydroborate ligand binds in a κ3 fashion, via three bridging hydrogen atoms. IR spectroscopy data are consistent with the solid-state structure and the corresponding BD4 analog of 4 shows the expected IR isotope shifts. The 1H NMR spectra of 3 and 4 shows one set of resonances each for the BH4 and the pyrazolylborate ligands indicating dynamic solution behavior. For complex 3, although X-ray quality crystals could not be obtained, the IR and NMR data are consistent with its formulation as the solvent-free analog of complex 4 with κ3-bonded BH4 ligand. 相似文献
6.
Some lanthanide (Ln) complexes (Ln = Er, Nd, Yb) with an organic ligand, 6-diphenylamine carbonyl 2-pyridine carboxylic acid (HDPAP), have been synthesized. The crystal structure and near infrared luminescence of these complexes (Er-DPAP, Nd-DPAP and Yb-DPAP) have been investigated. The results showed that the lanthanide complexes have electroneutral structures and the near infrared (NIR) emission exhibits characteristic narrow emission of the lanthanide ions. The energy transfer mechanisms in the lanthanide complexes were discussed. 相似文献
7.
Feng L He X Xiao H Li Z Li F Liu N Chai Z Zhao Y Zhang Z 《Biological trace element research》2007,117(1-3):89-104
Lanthanides, because of their diversified physical and chemical effects, have been widely used in a number of fields. As a
result, more and more lanthanides are entering the environment and eventually accumulating in the human body. Previous studies
indicate that the impact of lanthanides on brain function cannot be neglected. Although neurological studies of trace elements
are of paramount importance, up to now, little data are provided regarding the status of micronutritional elements in rats
after prenatal and long-term exposure to lanthanide. The aim of this study is to determine the ytterbium (Yb) and trace elements
distribution in brain and organic tissues of offspring rats after prenatal and long-term exposure to Yb. Wistar rats were
exposed to Yb through oral administration at 0,0.1, 2, and 40 mg Yb/kg concentrations from gestation day 0 through 5 mo of
age. Concentrations of Yb and other elements (Mg, Ca, Fe, Cu, Mn, and Zn) in the serum, liver, femur, and brain regions (cerebral
cortex, hippocampus, cerebellum, and the rest) of offspring rats at the age of 0 d, 25 d, and 5 mo were analyzed by inductively
coupled plasma-mass spectrometry. The accumulation of Yb in the brain, liver, and femur is observed; moreover, the levels
of Fe, Cu, Mn, Zn, Ca, and Mg in the brain and organic tissues of offspring rats are also altered after Yb exposure. This
disturbance of the homeostasis of trace elements might induce adverse effects on normal physiological functions of the brain
and other organs. 相似文献
8.
Treatment of tris-cyclopentadienyl-ytterbium in thf with one equivalent of 2,6-di(tert-butyl)phenol, N,N-dimethyl-2-aminoethanol or N,N-diethyl-2-aminoethanol resulted in substitution of one cyclopentadienyl ligand and formation of [YbCp2(O-C6H3tBu-2,6)(thf)] (1), [{YbCp2(μ-OCH2CH2NMe2)}2] (2) or [{YbCp2(μ-OCH2CH2NEt2)}2] · (thf)2 (3), respectively. All compounds were characterised by spectroscopic and X-ray crystallographic techniques, the latter two also being studied by variable temperature 1H NMR spectroscopy. Compound (1) is mononuclear with the Yb centre bound by two η5-cyclopentadienyl ligands one O-bound thf and an O-bound phenoxy ligand. Compounds (2) and (3) are centrosymmetric dimers with the Yb centre bound by two η5-cyclopentadienyl ligands, while the bidentate ligands chelate the metal centre and also bridge to the adjacent Yb through the alkoxy oxygen atom. Variable temperature 1H NMR studies on compounds (2) and (3) show a solution-state equilibrium between the dimeric solid-state structure and one with the nitrogen atoms non-bound to Yb. 相似文献
9.
本文研究了不同剂量的稀土元素镱和铕,通过皮下注射对兔肝中金属硫蛋白生成的影响。用SephadexG50柱对兔肝提取液进行分离,收集的组分用紫外分光光度法、原子吸收光谱法和ELISA法进行分析。实验结果表明,低剂量(1-3ppm)的镱和铕不能明显地诱导兔肝内金属硫蛋白的合成,而高剂量(10-40ppm)的镱和铕可以诱导兔肝金属硫蛋白合成。 相似文献
10.
Ernestas Gaidamauskas Boris A. Kashemirov Kanokkarn Saejueng Charles E. McKenna Debbie C. Crans 《Journal of inorganic biochemistry》2009,103(12):1652-1657
The coordination chemistry of bisphosphonates with Yb3+ was investigated to evaluate the potential of the UV-vis based detection method using the Yb3+-pyrocatechol complexation reaction as a sensor for bisphosphonates. The complexation chemistry of Yb3+ with phosphate and ATP analogs was previously described (E. Gaidamauskas, K. Saejueng, A.A. Holder, S. Bharuah, B.A. Kashemirov, D.C. Crans, C.E. McKenna, J. Biol. Inorg. Chem. 13 (2008) 1291-1299), and we here studied the complexation chemistry of bisphosphonates in this system. The spectrophotometric assay yields direct evidence for formation of a 4:3 metal to ligand complex at neutral pH. Direct evidence for Yb3+:methylenebis(phosphonate) complexes with 1:1 and 1:2 stoichiometry was also obtained by potentiometry at acidic and basic pH. Direct evidence for complex formation was obtained using 1H NMR spectroscopy although the stoichiometry was not accessed at neutral pH. Our results suggest that the spectroscopic observation of the YbPV complex can be used to conveniently measure concentrations of bisphosphonates down to 2-3 μM. 相似文献