Nicotine-induced upregulation of antioxidant protein Prx 1 in oral squamous cell carcinoma

Nicotine is a source of exogenous oxidative stress, which is associated with the pathogenesis of numerous diseases including oral squamous cell carcinoma (OSCC), whereas an antioxidant protein, peroxiredoxin 1 (Prx 1), plays an important role in the modulation of this condition. This study was to investigate the association between Prx 1 and tobacco-induced oxidative stress. The expression of Prx 1 and GST in OSCC Tca8113 cells, which were pre-treated with nicotine, was determined. In the present study, MTT assay, reactive oxygen species (ROS) assay, RT-PCR and Western blot analyses, respectively, were conducted to assess cell viability, ROS level, and expression level of Prx 1 and GST in nicotine-treated Tca8113 cells. Nuclear factor kappa B (NF- B) expression was detected by immuno-fluorescence. Our results showed the growth of Tca8113 cells was increased in a dose-dependent manner when cells were treated with nicotine at concentrations from 0.1 to 10 mol/L, but the proliferation of the cells decreased at 100 mol/L. ROS levels increased in all groups treated with nicotine at concentrations of 0.1, 1, 10, or 100 mol/L for 24h. Prx 1 and GST mRNA and protein expression were up-regulated in cells treated with nicotine for the same time at different concentrations or at the same concentration for different times (P<0.05). NF-B was translocated from cytoplasm to nucleus, the expression of NF- B was increased in nucleus. These results suggest that up-regulation of Prx1 expression appears to be associated with tobacco-induced oxidative stress, which may play an important role in the pathogenesis of OSCC.     

Controlled expression of enhanced green fluorescent protein and hepatitis B virus precore protein in mammalian cells

A novel tetracycline regulation expression system was used to regulate the expression of enhanced green fluorescent protein (EGFP) and hepatitis B virus precore protein in the mammalian cell lines with lipofectAMINE. Flow cytometry assays showed that application of the system resulted in about 18-fold induction of EGFP expression in CHO cell lines and 5-fold induction in SSMC-7721 cells and about 2-fold in the HEK293 cells. Furthermore, the effective use of this system for the controlled expression of HBV precore protein gene in hepatocellular carcinoma cells was tested.     

Leaching of a copper flotation concentrate with ammonium persulfate in an autoclave system

The leaching behavior of a copper flotation concentrate was investigated using ammonium persulfate (APS) in an autoclave system. The decomposition products of APS, active oxygen, and acidic medium were used to extract metals from the concentrate. Leaching experiments were performed to compare the availability of APS as an oxidizing agent for leaching of the concentrate under atmospheric conditions and in an autoclave system. Leaching temperature and APS concentration were found to be important parameters in both leaching systems. Atmospheric leaching studies showed that the metal extractions increased with the increase in APS concentration and temperature (up to 333 K). A similar tendency was determined in the autoclave studies up to 423 K. It was also determined that the metal extractions decreased at temperatures above 423 K due to the passivation of the particle surface by molten elemental sulfur. The results showed that higher copper extractions could be achieved using an autoclave system.     

cDNA cloning and expression of erythropoietin in the plateau zokor （Myospalax baileyi） from the Qinghai-Tibet Plateau

All organisms respond to variation in their environments and manage environmental stress through metabolic adjustments.The plateau zokor(Myospalax baileyi) is an endemic and keystone subterranean rodent species that inhabits the Qinghai-Tibet Plateau between 2800 and 4200 m above sea level.It is a hypoxic-tolerant mammal with a high ratio of oxygen utilization that enables it to cope with its harsh surroundings.To explore the molecular mechanism of altitude acclimatization of the plateau zokor,we cloned the zokor erythropoietin(Epo) gene and used real-time PCR to compare Epo mRNA levels in zokors inhabiting 16 different altitudes.The full-length zokor Epo open reading frame was 579 bp that encoded a precursor peptide of 192 amino acids with a signal peptide of 26 residues.The Epo gene of the plateau zokor was 81%-95% homologous to that of human,mouse,rat,root vole and the Golan Heights blind mole rat,with the highest homology(95%) to species of the genus Spalax.Epo mRNA was detected mainly in the zokor kidney and spleen among 8 selected tissues.The level of Epo mRNA increased in the liver and kidney with increases in altitude.The increase in the kidney was 5 times that in the liver.Remarkably,expression of Epo mRNA in the kidney of zokors living at the highest altitude(4268 m) was 12-fold higher than that of zokors living at the lowest(2492 m) altitude.These findings provide essential information for understanding the possible role of Epo in adaptation to hypoxia in the plateau zokor.     

Prokaryotic expression and characterization of a pea actin isoform （PEAcl） fused to GFP

Actins widely exist in eukaryotic cells and play important roles in many living activities. As there are many kinds of actin isoforms in plant cells,it is difficult to purifyeach actin isoform in sufficient quantities for analysing itsphysicochemical properties. In the present study, apea(pisum Sativum L.)actin isoform (PEAc1)fused to His-tag at its amino terminus and GFP(green fluorescent protein)atits Carboxyl terminus were expressed in E. coli in inclusionbodies. The fusion protein (PEAc1-GFP)was highly purifiedwith the yield of above 2 mg/L culture by dissolving inclu-sions in 8 mol/L urea,renaturing by dialysis in a gradient of urea,and affinity binding to Ni-resin. The purified mono-meric PEAc1-GFP could efficiently bind on DNase I andinhibit the latter抯 enzyme activity. PEAc1-GFP could po-lymerise into green fluorescent filamentous structures(F-PEAc1-GFP),which could be labelled byTRITC-phalloidin,a specific agent for observing microfila-ments. The PEAc1-GFP polymerlzation curve was identicalwith that of chicken skeletal muscle actin. The critical con-centration for PEAc1-Gfp to polymerise into filaments is 0.24 μmol/L.The F-PEAc1-GFP could stimulate myosinMg-ATPase activity in a protein concentration dependantmanner (about 4 folds at 1 mg/mL F-PEAc1-GFP). The re-sults above show that the PEAc1 fused to GFP retained theassembly characteristic of actin, indicating that gene fusion,prokaryotic expression, denaturation and renaturation,andaffinity chromatography is a useful strategy for obtainingplant actin isoform proteins in a large amount.     

Promoter of soybean early nodulin gene<Emphasis Type="Italic">enod2B</Emphasis> is induced by rhizobial Nod factors in transgenic rice

Nod factors, which are signaling molecules produced by Rhizobia, are the principal determinants of host specificity in Rhizobium-legume symbiosis. Nod factors can elicit a number of characteristic developmental responses in the roots of legumes, such as depolarization of the membrane potential in epidermal cells, specific expression of early nodulin genes and changes in the flux of calcium in root hairs, deformation of root hairs, cell division in the root cortex and formation of the nodule primordinm. Whether the rice plant can respond to signaling molecules (i.e. Nod factors) is an important question, as it could establish the potential for symbiotic nitrogen fixation in rice. The promoter of the soybean (Glycine max) early nodulin gene Gmenod2B fused to the β-glucuronidase (GUS) reporter gene was used as a molecular marker to explore whether Nod factors can be recognized by rice cells as signaling molecules. Transgenic rice plants harboring the chimeric gene Gmenod2BP-GUS were obtained via an Agrobacterium tumefaciens-mediated system. NodNGR factors produced by a broad-host-range Rhizobium strain NGR234(pA28) were used as probes to investigate the activity of the Gmenod2B promoter in rice. Our results showed that the early nodulin gene Gmenod2B promoter was induced by NodNGR factors in transgenic rice, and that it was specifically expressed in rice plant roots. Moreover, GUS gene expression driven by the Gmenod2B promoter in transgenic rice was regulated by nitrogen status. These findings indicated that rice possessed the ability to respond to Nod factor signals, and that this signal transduction system resulted in activation of the Gmenod2B promoter. Thus, we predict that the Nod-factor inducible nodulin expression system, which is similar to Rhizobium-legume symbiosis, may also exist in rice.     

Hydrometallurgical application for treating a Nigerian chalcopyrite ore in chloride medium:Part I.Dissolution kinetics assessment

The dissolution kinetics of a Nigerian chalcopyrite ore in hydrochloric acid was studied in this article.Acid concentration,reaction temperature,and ore particle size were chosen as experimental parameters.The chemical and morphological studies of the ore before and after leaching at optimal conditions were carried out by X-ray difraction(XRD)and scanning electron microscopy(SEM).It is revealed that increasing the acid concentration and system temperature and decreasing the ore particle size greatly enhances the dissolution rate.The dissolution kinetics was found to follow the shrinking core model for the difusion control mechanism where the activation energy(Ea)of 32.92 kJ·mol 1was obtained for the process and supported by morphological changes at a higher dissolution of 91.33%.     

Green fluorescent protein （GFP） transsenic pig produced by somatic cell nuclear transfer

Transgenic somatic cell nuclear transfer is a very promising route for producing transgenic farm animals. Research on GFP transgenic pigs can provide useful information for breeding transgenic pigs, human disease models and human organ xenotransplantation. In this study, a liposomal transfecUon system was screened and transgenic embryos were reconstructed by nuclear transfer of GFP positive cells into enucleated in vitro matured oocytes. The development of reconstructed embryos both in vitro and in vivo was observed, and GFP expression was determined. The results showed that porcine fe- tal-derived fibroblast cells cultured with 4.0 μL/mL liposome and 1.6 μg/mL plasmid DNA for 6 h resulted in the highest transfecUon rate （3.6%）. The percentage of GFP reconstructed embryos that de- veloped in vitro to the blastocyst stage was 10%. Of those the GFP positive percentage was 48%. Reconstructed transgenic embryos were transferred to 10 recipients. 5 of them were pregnant, and 3 delivered 6 cloned piglets in which 4 piglets were transgenic for the GFP as verified by both GFP protein expression and GFP DNA sequence analysis. The percentage of reconstructed embryos that resulted in cloned piglets was 1.0%; while the percentage of piglets that were transgenic was 0.7%. This is the first group of transgenic cloned pigs born in China, marking a great progress in Chinese transgenic cloned pig research.     

Effect of pH values on the extracellular polysaccharide secreted by Acidithiobacillus ferrooxidans during chalcopyrite bioleaching

The pH value plays an important role in the bioleaching of sulphide minerals. The effect of pH values on the extracellular poly-saccharide secreted by Acidithiobacillus ferrooxidans was investigated in different phases of bacterial growth during chalcopyrite bioleach-ing. It is found that extracellular polysaccharide secretion from the cells attached to chalcopyrite is more efficiently than that of the free cells in the bioleaching solution. Three factors, pH values, the concentration of soluble metal ions, and the bacterial growth and metabolism, affect extracellular polysaccharide secretion in the free cells, and are related to the bacterial growth phase. Extracellular polysaccharide secretion from the attached cells is mainly dependent on the pH value of the bacterial culture.     

Experimental Study of High Moisture Content Gas Flow Across a Cylinder at Moderate Reynolds Numbers

The Nusselt number for cross flow of a mixture of air and vapor over a cylinder was measured at moderate Reynolds numbers (3000-7000) for temperatures from 300℃ to 700℃ and for vapor mass fractions of 0. 18 - 0. 35. Results are also presented for a set of three cylinders aligned perpendicular to the flow for the same range of conditions, The effect of the vapor concentration and temperature on the convection coefficients was investigated to develop a modified Zhukauskas correlation. The results show that the Nusselt number increases as the moisture content increases and that the increase is more than could be accounted for by typical models for the property variations of mixtures. The exponent of the vapor concentration term in the modified correlation is 0. 145 for the entire data set indicating the importance of the property variation due to the moisture content.     

In situ observation of C60（C（COOH）2）2 interacting with living cells using fluorescence microscopy

1 Introduction In recent years, studies on biological effects of thenanoscale materials have become the cornerstone of rapidly developed nanomedical and nanobiological technologies. Moreover, studies on the bio-effects when the different kinds of nanoscal…     

The formation and stability of Si1-x C x alloys in Si implanted with carbon ions

Si_1-xC_x alloys of carbon (C) concentration between 0.6%—1.0% were grown in Si by ion implantation and high temperature annealing. The formation of Si_1-xC_x alloys under different ion doses and their stability during annealing were studied. If the implanted dose was less than that for amorphizing Si crystals, the implanted C atoms would like to combine with defects produced during implantation and it was difficult to form Si_1-xC_x alloys after being annealed at 850℃. With the increment of implanted C ion doses, the lattice damage increased and it was easier to form Si_1-xC_x alloys. But the lattice strain would become saturate and only part of implanted carbon atoms would occupy the substitutional positions to form Si_1-xC_x alloys as the implanted carbon dose increased to a certain degree. Once Si_1-xC_x alloys were formed, they were stable at 950℃, but part of their strain would release as the annealing temperature increased to 1 000℃. Stability of the alloys became worse with the increment of carbon concentration in the alloys.     

Hydrothermal synthesis of pyrrhotite (Fex-1S) nanoplates and their antibacterial, cytotoxic activity study

The aim of this study was to synthesize and characterize Fe_(x-1)S 2D-nanostructures with pyrrhotite phase,as well as to explore their biological(antibacterial and cytotoxic)properties,namely the expression of reactive oxygen species(ROS)in the exposure of cells and bacteria.Based on hydrothermal synthesis,the characterization of asprepared 2D-nanostructures was performed by XRD,SEM,EDS,and TEM,in which the single-crystalline pyrrhotite phased Fe_(x-1)S nanoplate morphology was observed.The antibacterial activities of Fe_(x-1)S nanoplates against human pathogenic strains such as Staphylococcus aureus,Escherichia coli,and Enterococcus faecalis were tested.Minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)were determined following the broth microdilution method.Cytotoxicity and expression of intracellular ROS of pyrrhotite nanoplates on Human Gingival Fibroblast(HGF),Human Pulp Cells(HPC)and Human Osteoblast(HBC)were calculated.Cell viability was determined by the MTT method.All experiments were performed of three independent experiments and data were analyzed by Kruskal-Wallis and Mann-Whitney tests,also Pearson′s Correlation was performed.The nanoplates exhibited good bactericidal effect.All types of cells tested showed slight cytotoxicity.It was found that intracellular ROS is produced when cells and bacteria tested are exposed to pyrrhotite nanoplates in presence of both air and peroxide hydrogen.ROS production levels were higher in the bacteria than the cells exposed to these nanoplates.     

Induced temperature-dependent DNA degradation by C60 without photoactivation

This study shows that C₆₀ can degrade pBR322 plasmid DNA at room temperature without photoactivation. The degradation was enhanced by increasing incubation temperature, reaction time or C₆₀ concentration. We also found that superoxide radical anions (O ₂ ^?· ) were formed in the C₆₀ solution. Superoxide dismutase significantly inhibited DNA cleavage and O ₂ ^?· generation induced by C₆₀. These results suggest that DNA cleavage was caused by the formation of reactive oxygen species induced by C₆₀ at room temperature. Furthermore, we demonstrate that the DNA degradation was significantly inhibited by acid amide chemicals such as formamide, and by increased ionic strength of the reaction solution. These results indicate that the DNA conformation stability and the surface properties of C₆₀ are important factors regulating DNA degradation. We propose that C₆₀ can bind DNA, decrease DNA conformation stability, and induce the formation of reactive oxygen species and DNA cleavage at room temperature. Our results provide a possible explanation for the genotoxicity of C₆₀, which should be considered in future use of this particular nano-material.     

Spatial and temporal variations of C3/C4 relative abundance in global terrestrial ecosystem since the Last Glacial and its possible driving mechanisms

The primary factor controlling C 3 /C 4 relative abundance in terrestrial ecosystem since the Last Glacial has been widely debated. Now more and more researchers recognize that climate, rather than atmospheric CO 2 concentration, is the dominant factor. However, for a specific area, conflicting viewpoints regarding the more influential one between temperature and precipitation still exist. As temperature and precipitation in a specific area usually not only vary within limited ranges, but also covary with each other, it is difficult to get a clear understanding of the mechanism driving C 3 /C4 relative abundance. Therefore, systematic analysis on greater spatial scales may promote our understanding of the driving force. In this paper, records of C3/C4 relative abundance since the Last Glacial on a global scale have been reviewed, and we conclude that: except the Mediterranean climate zone, C3 plants predominated the high latitudes during both the Last Glacial and the Holocene; from the Last Glacial to the Holocene, C4 relative abundances increased in the middle latitudes, but decreased in the low latitudes. Combining with studies of modern process, we propose a simplified model to explain the variations of C3 /C4 relative abundance in global ecosystem since the Last Glacial. On the background of atmospheric CO2 concentration since the Last Glacial, temperature is the primary factor controlling C3/C4 relative abundance; when temperature is high enough, precipitation then exerts more influence. In detail, in low latitudes, temperature was high enough for the growth of C4 plants during both the Last Glacial and the Holocene; but increased precipitation in the Holocene inhibited the growth of C4 plants. In middle latitudes, rising temperature in the Holocene promoted the C4 expansion. In high latitudes, temperature was too low to favor the growth of C4 plants and the biomass was predominated by C3 plants since the Last Glacial. Our review would benefit interpretation of newly gained records of C3/C4 relative abundance from different areas and different periods, and has its significance in the understanding of the driving mechanisms of C3/C4 variations on longer timescales (e.g., since the late Miocene) with reliable records of temperature and atmospheric CO2 concentration.     

Synthesis and assembly with mesoporous silica of platinum(II) porphyrin complexes bearing carbazyl groups:Luminescent and oxygen sensing properties

Determination of oxygen is very important in vari- ous fields such as analytical chemistry, medical chem- istry and environmental and industrial applications[1]. The optical oxygen sensors are based upon the princi- ple that oxygen is a powerful quencher …     

Zr-pillared montmoril lonite supported cobalt nanoparticles for Fischer – Tropsch synthesis

In this article Fischer–Tropsch(FT) synthesis was studied over cobalt nanoparticles supported on modifed Montmorillonite(Zr-PILC).Co-loaded/Zr-PILC catalysts were synthesized by hydrothermal methods and were characterized by XRD,XRF,BET,H2-TPR,TGA and SEM techniques.FT reactions were carried out in fxed bed microreactor(T 225 1C,260 1C and 275 1C,P 1,5 and 10 bars).The FT-products obtained over Co-loaded/Zr-PILC catalysts showed increased selectivity of C2–C12hydrocarbons and decreased selectivity towards CH4and higher molecular weight hydrocarbons(C21) at a TOS of 2–30 h as compared to the Co-loaded/NaMMT catalysts.With increase in reaction temperature from225 1C to 275 1C,CO-conversion and CH4selectivity increases while that of C5+hydrocarbons decreases.Decrease in CH4selectivity while increase in C5+hydrocarbons and CO-conversion were observed on increasing the pressure of reaction.     

Pedogenic carbonate isotope record of vegetational evolution since late Miocene in Loess Plateau

Isotopic analyses for paleovegetational evolution have been carried out on samples of the pedogenic carbonate nodules in the Red Clay-Loess sequence at Lingtai (35°N), the Loess Plateau. Stable carbon isotopic composition indicates that ( i ) C4 plants might be present at least by7.0 Ma; ( ii ) C4 plants expanded gradually between ～4.0 and ～3.2 Ma, and their biomass fraction was up to 50% ; and (Ⅲ ) the biomass of C4 vegetation since ～2.0 Ma seems to have been decreased to the level (about 20%) before 4.0 Ma. C4 plant expansion at Lingtai cannot be fully understood with the "global C4 expansion" model because it occurred much later up to 3.0 Ma than in Pakistan, which indicates that some changes in the regional climatic system may also contribute to C3/C4 shift except changes in atmospheric CO2 concentrations and temperature. The latitudinal zone for C3/C4 transition seems to move southwards slightly in East Asia, compared with the case in North America where 37°N癗 is the ideal boundary for the C4 expansion.     

Temperature effects on ethylene and methane production from temperate forest soils

Change in temperature affects the activity of soil microorganisms.However,there is limited knowledge about temperature effects on ethylene(C2H4) and methane(CH4) production from forest soils.Topsoil samples(0―5 cm) collected from different temperate forest stands(e.g.,Pinus sylvestris L.,Cryptomeria japonica,and Quercus serrata) were used to compare C2H4 and CH4 production from soils at temperature from 5 to 35℃ under oxic and anoxic conditions.The rates of C2H4 and CH4 production from soils under oxic cond...     

Near-MDR codes over Z 4

In this paper, we define near-MDR （maximum distance with respect to rank） codes over the ring Z4 and prove that a linear code C over Z4 is near-MDR if and only if the torsion codes Tor（C）is near-MDS. Finally, the generator matrices of all near-MDR codes over Z4 are given.