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91.
Induction of neuronal apoptosis by thiol oxidation: putative role of intracellular zinc release 总被引:14,自引:0,他引:14
Aizenman E Stout AK Hartnett KA Dineley KE McLaughlin B Reynolds IJ 《Journal of neurochemistry》2000,75(5):1878-1888
The membrane-permeant oxidizing agent 2,2'-dithiodipyridine (DTDP) can induce Zn(2+) release from metalloproteins in cell-free systems. Here, we report that brief exposure to DTDP triggers apoptotic cell death in cultured neurons, detected by the presence of both DNA laddering and asymmetric chromatin formation. Neuronal death was blocked by increased extracellular potassium levels, by tetraethylammonium, and by the broad-spectrum cysteine protease inhibitor butoxy-carbonyl-aspartate-fluoromethylketone. N,N,N', N'-Tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and other cell-permeant metal chelators also effectively blocked DTDP-induced toxicity in neurons. Cell death, however, was not abolished by the NMDA receptor blocker MK-801, by the intracellular calcium release antagonist dantrolene, or by high concentrations of ryanodine. DTDP generated increases in fluorescence signals in cultured neurons loaded with the zinc-selective dye Newport Green. The fluorescence signals following DTDP treatment also increased in fura-2- and magfura-2-loaded neurons. These responses were completely reversed by TPEN, consistent with a DTDP-mediated increase in intracellular free Zn(2+) concentrations. Our studies suggest that under conditions of oxidative stress, Zn(2+) released from intracellular stores may contribute to the initiation of neuronal apoptosis. 相似文献
92.
The influence of hepatic metallothionein (MT) and zinc (Zn) on glycolysis was investigated in primary cultures of mouse hepatocytes
prepared from MT-normal (+/+) and MT-null (−/−) mice. In MT +/+ mice, a close relationship was observed between the Zn concentration
in the incubation medium (10–150 μM), increased MT levels in the cells, and increased glycolysis (accumulation of lactate + pyruvate) over 24 h, with significant
effects seen at physiological levels of Zn (10–25 μM). Hepatocytes from MT −/− mice had significantly lower basal rates of glycolysis and demonstrated increased glycolysis only
at Zn concentrations of 50 μM or greater. The lactate: pyruvate ratio was higher in the MT +/+ hepatocytes. The oxidation of endogenous fatty acid (accumulation
of the ketone bodies, 3-hydroxybutyrate and acetoacetate) was initially greater in the MT +/+ hepatocytes, although only MT
−/− hepatocytes showed increased ketone body production in response to Zn. The 3-hydroxybutyrate: acetoacetate ratio was higher
in the MT +/+ hepatocytes and increased with increasing Zn concentrations. Intracellular Zn accumulation was 60% greater in
the MT +/+ hepatocytes, with approximately 80% of the extra Zn associated with MT. The results implicate MT-associated Zn
rather than increased intracellular Zn per se in the regulation of hepatic carbohydrate metabolism. 相似文献
93.
Equilibrium sorption isotherm for metal ions on tree fern 总被引:6,自引:0,他引:6
A new sorbent system for removing heavy metal ions, such as Zn(II), Cu(II) and Pb(II), from aqueous solutions has been investigated. This new sorbent is tree fern, an agriculture product. Variables of the system include solution temperature and sorbent particle size. The experimental results were fitted to the Langmuir, Freundlich and Redlich–Peterson isotherms to obtain the characteristic parameters of each model. Both the Langmuir and Redlich–Peterson isotherms were found to well represent the measured sorption data. According to the evaluation using the Langmuir equation, the maximum sorption capacities of metal ions onto tree fern were 7.58 mg/g for Zn(II), 10.6 mg/g for Cu(II) and 39.8 mg/g for Pb(II). It was noted that an increase in temperature resulted in a higher metal loading per unit weight of the sorbent. Decreasing the particle sizes of tree fern led in an increase in the metal uptake per unit weight of the sorbent. 相似文献
94.
Pieter C. A. Bruijnincx Martin Lutz Johan P. den Breejen Anthony L. Spek Gerard van Koten Robertus J. M. Klein Gebbink 《Journal of biological inorganic chemistry》2007,12(8):1181-1196
The coordination chemistry of the 2-His-1-carboxylate facial triad mimics 3,3-bis(1-methylimidazol-2-yl)propionate (MIm(2)Pr) and 3,3-bis(1-ethyl-4-isopropylimidazol-2-yl) propionate (iPrEtIm(2)Pr) towards ZnCl(2) was studied both in solution and in the solid state. Different coordination modes were found depending both on the stoichiometry and on the ligand that was employed. In the 2:1 ligand-to-metal complex [Zn(MIm(2)Pr)(2)], the ligand coordinates in a tridentate, tripodal N,N,O fashion similar to the 2-His-1-carboxylate facial triad. However, the 1:1 ligand-to-metal complexes [Zn(MIm(2)Pr)Cl(H(2)O)] and [Zn(iPrEtIm(2)Pr)Cl] were crystallographically characterized and found to be polymeric in nature. A new, bridging coordination mode of the ligands was observed in both structures comprising N,N-bidentate coordination of the ligand to one zinc atom and O-monodentate coordination to a zinc second atom. A rather unique transformation of pyruvate into oxalate was found with [Zn(MIm(2)Pr)Cl], which resulted in the isolation of the new, oxalato bridged zinc coordination polymer [Zn(2)(MIm(2)Pr)(2)(ox)].6H(2)O, the structure of which was established by X-ray crystal structure determination. 相似文献
95.
Zhen Ma Yiqun Cao M. Fátima C. Guedes da Silva João J.R. Fraústo da Silva 《Journal of inorganic biochemistry》2010,104(7):704-711
Reactions between 4′-phenyl-terpyridine (L) and several Zn(II) salts (sulfate, nitrate, chloride or acetate) led to the formation of the complexes [Zn2(μ-O2SO2)2L2(CH3OH)2] (1), [Zn(NO3)L(H2O)]NO3 (2), [Zn(Cl)2L] (3) and [Zn(CH3COO)2L] (4) which were characterized by IR, 1H NMR and fluorescence spectroscopies, elemental analysis and single crystal X-ray diffraction. In the dinuclear molecule of 1 the Zn atom is hexacoordinated, with a N3O3 coordination environment and forms an octagonal ZnOSOZnOSO metallacycle. In the remaining structures, the metal atom is envisaged as possessing highly distorted N3X2 (X = O or Cl) square pyramid coordination geometries. The structure of 3 presents two different packing patterns which lead to distinct π-π stackings. In both structures 2 and 4, strong intermolecular hydrogen bonds were identified. The complexes exhibit promising in vitro tumor-inhibiting activities, which are higher than that of cisplatin, against the following human tumor cell lines: promyelocyticfina leukaemia (HL-60), hepatocellular carcinoma (Bel-7402), gastric carcinoma (BGC-823) and nasopharyngeal carcinoma (KB). 相似文献
96.
Yasmin H. Neggers Mary B. Dubard Robert L. Goldenberg Tsunenobu Tamura Kelley E. Johnston Rachel L. Copper John C. Hauth 《Biological trace element research》1996,55(1-2):127-135
Plasma zinc (Zn) concentrations were measured in 4376 indigent women (86% African-American), at a mean (±SD) gestational age
of 15 (±7.8) wk to determine the relationship between various maternal characteristics and plasma Zn levels during pregnancy.
Mean plasma Zn levels were lower in African-American women than in Caucasian women, in multiparous women than in primiparous
women, and in women with body weight >69.9 kg than in those with body weight ≤69.9 kg (p≤0.001 for each comparison). There were no significant differences related to maternal age, marital status, education, or
smoking habit. Multiple regression analysis, including maternal prepregnancy weight, race, age, parity, smoking habit, education,
and marital status indicated that race, parity, and pregnancy weight were significantly associated with maternal plasma Zn
levels, adjusted for gestational age. Maternal race was the best predictor of plasma Zn concentrations among the population
of pregnant women studied A significant proportion of variance in maternal plasma Zn levels remained unexplained after taking
into account various maternal characteristics. The reasons for lower plasma Zn levels in African-American women, compared
to Caucasian women, during pregnancy are unknown. 相似文献
97.
本文系用原子吸收光谱法测定了西安地区10例成人尸体和15例新生儿尸体的颅盖骨内Cu和zn的含量。结果求得成人颅骨中Cu正常含量(均数±标准差)为4.48±3.78mg/kg(干组织重);zn为597.05±472.54mg/kg。新生儿颅骨中Cu和zn的含量分别为1.96±0.76mg/kg;1160.38±859.71mg/kg。结果表明,成人颅骨内Cu含量高于新生儿,而成人颅骨内Zn含量显著低于新生儿。 相似文献
98.
Hannan MA Faraji B Tanguma J Longoria N Rodriguez RC 《Biological trace element research》2009,127(1):6-15
The dietary intake of zinc (Zn), iron (Fe), selenium (Se), and iodine (I) of 31 lactating Mexican–American women attending
the Hidalgo County WIC program in Rio Grande Valley (RGV), Texas was estimated from 24-h dietary recall interviews. Milk samples
were obtained from lactating mothers who had infants 3 months of age and younger. Milk samples were collected in two visits
to assess change in breast milk composition after 1–3 months postpartum: group A—after 30–45 days and group B—75–90 days.
Dietary intakes indicated that the study participants had significantly inadequate percent energy intakes than the DRI (Dietary
Recommended Intakes) percent recommended kilocalorie values but protein intakes were substantially higher than the percent
recommended values. The estimated percent Zn, Fe, Se, and I intakes were also significantly lower than the DRI percent recommended
values. The lactating mothers consumed significantly less Zn, Se, and I when compared to the Recommended Dietary Allowances
(RDA) even though Fe intake was higher than the RDA value. Breast milk concentration of Zn, Fe, and Se were in agreement within
the range of representative values for Constituents of Human Milk but I has significantly less concentration than the representative
value. There was no statistically significant correlation observed between dietary intake and milk concentration of Zn, Fe,
Se, and I. This study compares the estimated dietary intake of zinc, iron, selenium, and iodine to the concentration of these
trace elements in the maternal milk of lactating women of Mexican–American heritage who attend the Rio Grande Valley WIC clinic. 相似文献
99.
Zn efficiency (ZE) is the ability of plants to maintain high yield under Zn-deficiency stress in the soil. Two bean (Phaseolus vulgaris L.) genotypes that differed in ZE, Voyager (Zn-efficient) and Avanti (Zn-inefficient), were used for this investigation. Plants were grown under controlled-environment conditions in chelate-buffered nutrient solution where Zn2+ activities were controlled at low (0.1 pM) or sufficient (150 pM) levels. To investigate the relative contribution of the root versus the shoot to ZE, observations of Zn-deficiency symptoms in reciprocal grafts of the two genotypes were made. After growth under low-Zn conditions, plants of nongrafted Avanti, self-grafted Avanti and reciprocal grafts that had the Avanti shoot scion exhibited Zn-deficiency symptoms. However nongrafted and self-grafted Voyager, as well as reciprocal grafts with the Voyager shoot scion, were healthy with no visible Zn-deficiency symptoms under the same growth conditions. More detailed investigations into putative shoot-localized ZE mechanisms involved determinations of leaf biomass production and Zn accumulation, measurements of subcellular Zn compartmentation, activities of two Zn-requiring enzymes, carbonic anhydrase and Cu/Zn-dependent superoxide dismutase (Co/ZnSOD), as well as the non-Zn-requiring enzyme nitrate reductase. There were no differences in shoot tissue Zn concentrations between the Zn-inefficient and Zn-efficient genotypes grown under the low-Zn conditions where differences in ZE were exhibited. Shoot Zn compartmentation was investigated using radiotracer (65Zn) efflux analysis and suggested that the Zn-efficient genotype maintains higher cytoplasmic Zn concentrations and less Zn in the leaf-cell vacuole, compared to leaves from the Zn-inefficient genotype under Zn deficiency. Analysis of Zn-requiring enzymes in bean leaves revealed that the Zn-efficient genotype maintains significantly higher levels of carbonic anhydrase and Cu/ZnSOD activity under Zn deficiency. While these data are not sufficient to allow us to determine the specific mechanisms underlying ZE, they certainly point to the shoot as a key site where ZE mechanisms are functioning, and could involve processes associated with Zn compartmentation and biochemical Zn utilization.Abbreviations
CA
Carbonic anhydrase
-
NR
Nitrate reductase
-
SOD
Superoxide dismutase
-
ZE
Zinc efficiency
This research was supported by a graduate fellowship awarded to G.H. by The Republic of Turkey 相似文献
100.
Cellular compartmentation of cadmium and zinc in relation to other elements in the hyperaccumulator Arabidopsis halleri 总被引:21,自引:0,他引:21
The cellular compartmentation of elements was analysed in the Zn hyperaccumulator Arabidopsis halleri (L.) O'Kane & Al-Shehbaz (=Cardaminopsis halleri) using energy-dispersive X-ray microanalysis of frozen-hydrated tissues. Quantitative data were obtained using oxygen as
an internal standard in the analyses of vacuoles, whereas a peak/background ratio method was used for quantification of elements
in pollen and dehydrated trichomes. Arabidopsis halleri was found to hyperaccumulate not only Zn but also Cd in the shoot biomass. While large concentrations of Zn and Cd were found
in the leaves and roots, flowers contained very little. In roots grown hydroponically, Zn and Cd accumulated in the cell wall
of the rhizodermis (root epidermis), mainly due to precipitation of Zn/Cd phosphates. In leaves, the trichomes had by far
the largest concentrations of Zn and Cd. Inside the trichomes there was a striking sub-cellular compartmentation, with almost
all the Zn and Cd being accumulated in a narrow ring in the trichome base. This distribution pattern was very different from
that for Ca and P. The epidermal cells other than trichomes were very small and contained lower concentrations of Zn and Cd
than mesophyll cells. In particular, the concentrations of Cd and Zn in the mesophyll cells increased markedly in response
to increasing Zn and Cd concentrations in the nutrient solution. This indicates that the mesophyll cells in the leaves of
A. halleri are the major storage site for Zn and Cd, and play an important role in their hyperaccumulation.
Received: 4 April 2000 / Accepted: 16 May 2000 相似文献