Nano-selenium alleviates cadmium-induced cerebellar injury by activating metal regulatory transcription factor 1 mediated metal response

This study aims to investigate the role of metal regulatory transcription factor 1(MTF1)-mediated metal response in cadmium(Cd)-induced cerebellar injury,and to evaluate the antagonistic effects of nanoselenium(Nano-Se)against Cd toxicity.A total of 80 chicks(1 d old,male,Hy-Line Variety White)were randomly allocated to 4 treatment groups for 3 months:the control group(fed with a basic diet,n=20),the Nano-Se group(basic diet with 1 mg/kg nano-Se 1 mg/kg Nano-Se in basic diet,n=20),the NanoSe+Cd group(basic diet with 1 mg/kg Nano-Se and 140 mg/kg Cd Cl_(2),n=20)and the Cd group(basic diet with 140 mg/kg Cd Cl_(2),n=20).The results of the experiment showed that the Purkinje cells were significantly decreased with their degradation and indistinct nucleoli after Cd exposure.Moreover,exposure to Cd caused a significant accumulation of Cd and cupper.However,the contents of Se,iron,and zinc were decreased,thereby disturbing the metal homeostasis in the cerebellum.The Cd exposure also resulted in high levels of malondialdehyde(MDA)and down regulation of selenoprotein transcriptome.Furthermore,the expressions of MTF1,metallothionein 1(MT1),MT2,zinc transporter 3(ZNT3),ZNT5,ZNT10,zrt,irt-like protein 8(ZIP8),ZIP10,transferrin(TF),ferroportin 1(FPN1),ATPase copper transporting beta(ATP7B),and copper uptake protein 1(CTR1)were inhibited by Cd exposure.However,all these changes were significantly alleviated by the supplementation of Nano-Se.This study proved that Cd could disorder metal homeostasis and induce oxidative stress,whereas Nano-Se could relieve all these negative effects caused by Cd via activating the MTF1-mediated metal response in the cerebellum of chicken.

CLONING AND CHARACTERIZATION OF A METAL RESPONSIVE ELEMENT-CONTAINING FRAGMENTF ROM THE WILSON DISEASE GENE LOCUS BY JUNCTION TRAPPING

All mammalian metallothionein genes studied to date have several metal responsive elements (MRE) with consensus sequences of TGCRCNC (R, purine) in their regulatory region. MRE-like sequences were also found in many other metal-related genes. To see whether there is also such a sequence at the genetic locus (13q14. 3) of Wilson disease, which is a genetic disorder of copper metabolism, junction-trapping method based on the MRE sequence was used. A fragment containing MRE and MRE-like sequences from YAC 27D8 at the WND locus was successfully cloned and mapped back to the YAC by PCR. Presence of such a sequence in the copper transporter gene at the WD locus might imply that it has a possible interesting role in the regulation of WD gene expression.

Manganese antagonizes iron blocking mitochondrial aconitase expression in human prostate carcinoma cells

Aim： To investigate the possible role of manganese in the regulation of mitochondrial aconitase （mACON） activity human prostate carcinoma cell line PC-3 cells. Methods： The mACON enzymatic activities of human prostate carcinoma cell line PC-3 cells were determined using a reduced nicotinamide adenine dinucleotide-coupled assay. Immunoblot and transient gene expression assays were used to study gene expression of the mACON. The putative response element for gene expression was identified using reporter assays with site-directed mutagenesis and electrophoretic mobility-shift assays. Results： In vitro study revealed that manganese chloride （MnCI2） treatment for 16 h inhibited the enzymatic activity of mACON, which induced the inhibition of citrate utility and cell proliferation of PC- 3 cells. Although results from transient gene expression assays showed that MnCI2 treatment upregulated gene translation by approximately 5-fold through the iron response element pathway, immunoblot and reporter assays showed that MnCl2 treatments inhibited protein and gene expression of mACON. This effect was reversed by cotreatment with ferric ammonium citrate. Additional reporter assays with site-directed mutagenesis and electrophoretic mobility-shift assays suggested that a putative metal response element in the promoter of the mACON gene was involved in the regulation of MnCh on the gene expression of mACON. Conclusion： These findings suggest that manganese acts as an antagonist of iron, disrupting the enzymatic activity and gene expression of mACON and citrate metabolism in the prostate.

Improvement of Copper-inducible Gene Expression System for Plant

The copper-regulated gene expression system has been developed to control spacial and temporal expression of transgene in plant. It comprises two parts: (1) ace I gene encoding copper-responsive transcription factor under the control of a constitutive or organ-specific promoter, and (2) a gene of interest under the control of a chimeric promoter consisting of the CaMV 35S (-90 to +8) promoter linked to the metal responsive element (MRE) carrying activating copper-metallothionein expression (ACE1)-binding sites. Here, the effectiveness of two different ACE1-binding cis -elements which derive from 5'-regulatory region of yeast metallothionein gene was investigated in transgenic tobacco (Nicotiana tabacum L. cv. W38). The results revealed that the MRE (-210 to -126) could increase the system inducibility by 50% - 100% compared with the previously reported MRE (-148 to -105). It is potential to use the copper-inducible system to control valuable gene traits in plant biotechnology.

Manganese antagonizes iron blocking mitochondrial aconitase expression in human prostate carcinoma cells

Aim:To investigate the possible role of manganese in the regulation of mitochondrial aconitase(mACON)activity human prostate carcinoma cell line PC-3 cells.Methods:The mACON enzymatic activities of human prostate carcinoma cell line PC-3 cells were determined using a reduced nicotinamide adenine dmucleotide-coupled assay. Immunoblot and transient gene expression assays were used to study gene expression of the mACON.The putative response element for gene expression was identified using reporter assays with site-directed mutagenesis and electro- phoretic mobility-shift assays.Results:In vitro study revealed that manganese chloride(MnCl2)treatment for 16h inhibited the enzymatic activity of mACON,which induced the inhibition of citrate utility and cell proliferation of PC- 3 cells.Although results from transient gene expression assays showed that MnCl_2,treatment upregulated gene translation by approximately 5-fold through the iron response element pathway,immunoblot and reporter assays showed that MnCl_2 treatments inhibited protein and gene expression of mACON.This effect was reversed by co- treatment with fenic ammonium citrate.Additional reporter assays with site-directed mutagenesis and electrophoretic mobility-shift assays suggested that a putative metal response element in the promoter of the mACON gene was involved in the regulation of MnCl_2 on the gene expression of mACON.Conclusion:These findings suggest that manganese acts as an antagonist of iron,disrupting the enzymatic activity and gene expression of mACON and citrate metabolism in the prostate.

A novel dithiourea and its response to metal ions

The synthesis,characterization,and its response to metal ions of a novel thiourea N,N＇-diethoxycarbonyl-A＂,iV″＇-（1,2- ethylidene） dithiourea was reported.The results show that this dithiourea with new structure can react with Cu^（2＋） and Ni^（2＋） separately,and has a best selectivity to Fe^（3＋） ions.Bench-scale flotation tests were also carried out,verifying it has higher copper flotation recovery and better selectivity to sulfide ores containing Cu compared with universal collectors.

Lattice plasmon mode excitation via near-field coupling

The optical response of metal nanoparticles can be modified through near-field or far-field interaction,yet the lattice plasmon modes(LPMs)considered can only be excited from the latter.Here instead,we present a theoretical evaluation for LPM excitation via the near-field coupling process.The sample is an arrayed structure with specific units composed of upper metal disks,a lower metal hole and a sandwiched dielectric post.The excitation process and underlying mechanism of the LPM and the influence of the structure parameters on the optical properties have been investigated in detail by using a finite-difference time-domain(FDTD)numerical method.Our investigation presented here should advance the understanding of near-field interaction of plasmon modes for LPM excitation,and LPMs could find some potential applications,such as in near-field optical microscopes,biosensors,optical filters and plasmonic lasers.

Sodium glutamate and gamma-aminobutyric acid affect iron metabolism in the rat caudate putamen

Glutamic acid and gamma-aminobutyric acid （GABA） influence iron content in the substantia nigra and globus pallidus, although the mechanisms of action remain unclear. The present study measured iron content and changes in divalent metal transporter 1 （DMT1） and hephaestin expression in the substantia nigra and caudate putamen, and explored the effects of GABA and glutamic acid on iron metabolism. Results demonstrated that iron content and DMT1 non iron response element [DMT1 （-IRE）] expression were significantly greater but hephaestin expression was significantly lower in the caudate putamen of the monosodium glutamate group compared with the control group. No significant difference in iron content was detected between the GABA and control groups. DMT1 （-IRE） expression was significantly reduced, but hephaestin expressiori was significantly increased in the GABA group compared with the control group. In addition, there was no significant difference in tyrosine hydroxylase expression between monosodium glutamate and GABA groups and the control group. These results suggested that glutamate affected iron metabolism in the caudate putamen by increasing DMTI（-IRE） and decreasing hephaestin expression. In addition, GABA decreased DMT1 （-IRE） expression in the caudate putamen.

New insight into adsorption characteristics and mechanisms of the biosorbent from waste activated sludge for heavy metals

The adsorption characteristics and mechanisms of the biosorbent from waste activated sludge were investigated by adsorbing Pb2＋and Zn2＋in aqueous single-metal solutions. A p H value of the metal solutions at 6.0 was beneficial to the high adsorption quantity of the biosorbent. The optimal mass ratio of the biosorbent to metal ions was found to be 2. A higher adsorption quantity of the biosorbent was achieved by keeping the reaction temperature below 55°C. Response surface methodology was applied to optimize the biosorption processes, and the developed mathematical equations showed high determination coefficients（above 0.99 for both metal ions） and insignificant lack of fit（p = 0.0838 and 0.0782 for Pb2＋and Zn2＋, respectively）. Atomic force microscopy analyses suggested that the metal elements were adsorbed onto the biosorbent surface via electrostatic interaction. X-ray photoelectron spectroscopy analyses indicated the presence of complexation（between –NH2,-CN and metal ions） and ion-exchange（between –COOH and metal ions）. The adsorption mechanisms could be the combined action of electrostatic interaction, complexation and ion-exchange between functional groups and metal ions.