445 resultados para CU2
Resumo:
A vipp1 mutant of Synechocystis sp. PCC 6803 could not be completely segregated under either mixotrophic or heterotrophic conditions. A vipp1 gene with a copper-regulated promoter (P-petE-vipp1) was integrated into a neutral platform in the genome of the merodiploid mutant. The copper-induced expression of P-petE-vipp1 allowed a complete segregation of the vipp1 mutant and observation of the phenotype of Synechocystis 6803 with different levels of vesicle-inducing protein in plastids 1 (Vipp1). When P-petE-vipp1 was turned off by copper deprivation, Synechocystis lost Vipp1 and photosynthetic activity almost simultaneously, and at a later stage, thylakoid membranes and cell viability. The photosystem II (PSII)-mediated electron transfer was much more rapidly reduced than the PSI-mediated electron transfer. By testing a series of concentrations, we found that P-petE-vipp1 cells grown in medium with 0.025 mu M Cu2+ showed no reduction of thylakoid membranes, but greatly reduced photosynthetic activity and viability. These results suggested that in contrast to a previous report, the loss of photosynthetic activity may not have been due to the loss of thylakoid membranes, but may have been caused more directly by the loss of Vipp1 in Synechocystis 6803.
Resumo:
Total alkaline phosphatase activity (APA) and soluble reactive phosphorus (SRP) concentrations were measured in municipal wastewater, and a shallow Chinese freshwater lake receiving it. Activities of Dissolved alkaline phosphatase ( ADAP) in overlying and interstitial water were also analyzed monthly at three sites for several years. The lake was enriched with SRP and alkaline phosphatase by discharge of the wastewater, indicating that the inclusion of APA for estimating water pollution was reasonable. Annual data showed that APA in coarser fraction was significantly higher at the site receiving more wastewaters, both in surface and overlying water, suggesting that resuspension of enzyme most likely occurred in the basin heavily discharged. ADAP was an order of magnitude higher in the wastewater than those in lake waters, and was generally higher in interstitial water, a feature more striking at the site receiving more discharges. Besides, it was irrespectively inhibited by Na2WO4, L-cysteine and EDTA-Na, but stimulated by Cu2+, Zn2+, CTAB and Triton X-100 in interstitial, overlying and surface waters. This similarity of responding patterns to the stressors indicated an analogy between dissolved alkaline phosphatase in water column and that in interstitial water, supporting the hypothesis that the polluted sediments act as source of dissolved alkaline phosphatase in eutrophic lakes.
Resumo:
The pressure dependence of the photoluminescence from ZnS : Mn2+, ZnS : Cu2+, and ZnS : Eu2+ nanoparticles were investigated under hydrostatic pressure up to 6 GPa at room temperature. Both the orange emission from the T-4(1) - (6)A(1) transition of Mn2+ ions and the blue emission from the DA pair transition in the ZnS host were observed in the Mn-doped samples. The measured pressure coefficients are -34.3(8) meV/GPa for the Mn-related emission and -3(3) meV/GPa for the DA band, respectively. The emission corresponding to the 4f(6)5d(1) - 4f(7) transition of Eu2+ ions and the emission related to the transition from the conduction band of ZnS to the t(2) level of Cu2+ ions were observed in the Eu- and Cu-doped samples, respectively. The pressure coefficient of the Eu-related emission was found to be 24.1(5) meV/GPa, while that of the Cu-related emission is 63.2(9) meV/GPa. The size dependence of the pressure coefficients for the Mn-related emission was also investigated. The Mn emission shifts to lower energies with increasing pressure and the shift rate (the absolute value of the pressure coefficient) is larger in the ZnS : Mn2+ nanoparticles than in bulk. Moreover, the absolute pressure coefficient increases with the decrease of the particle size. The pressure coefficients calculated based on the crystal field theory are in agreement with the experimental results. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Resumo:
The room-temperature photoluminescence (PL) of copper doped zinc sulfide (ZnS:Cu) nanoparticles were investigated. These ZnS:Cu nanoparticles were synthesized by a facile wet chemical method, with the copper concentration varying from 0 to 2 mol%. By Gaussian fitting, the PL spectrum of the undoped ZnS nanoparticles was deconvoluted into two blue luminescence peaks (centered at 411 nm and 455 nm, respectively), which both can be attributed to the recombination of the defect sates of ZnS. But for the doped samples, a third peak at about 500 nm was also identified. This green luminescence originates from the recombination between the shallow donor level (sulfur vacancy) and the t(2) level of Cu2+. With the increase of the CU2+ concentration, the green emission peak is systematically shifted to longer wavelength. In addition, it was found that the overall photoluminescence intensity is decreased at the Cu2+ concentration of 2%. The concentration quenching of the luminescence may be caused by the formation of CuS compound. (c) 2005 Elsevier B.V. All rights reserved.
Resumo:
Cu2+,pHCu2+Cu2+,;pH6Cu2+20 mg/L0.25 mm,,,Na+Ca2+Cu2+,0.1mol/L HCl96.1%Cu2+Thomas,10.94mg/gCu2+,
Resumo:
,Cu(I) 2-(2'-)(Hpbm)2-(2'-)(Hqbm)Cu(I)20wt%PMMA518.5-597.5nm0.097-0.249, 11.7-25.9µs 2, 2'-(H2dbm)Cu(I)Cu2(dbm)(PPh3)4PMMA (20 wt%)20wt%PMMA448.5475.5nm[Cu(Hdbm)(PPh3)]2[BF4]20wt%PMMA5110.150, 12.0
Resumo:
3(cdb3) BL21(DE3)pET28b-cdb337OD6000.61mM IPTG 30cdb3cdb3cdb3, cdb3- cdb3TrpGuHClcdb3 TrppH6.010.0cdb3Tm15pH 7.2pH9.2Cd2+Ca2+Cu2+Co2+Mg2 Zn2+cdb3Trp50Mcdb3cdb3N123TFETFE80% ATPcdb3ATP3mMcdb3
Resumo:
1XPS510-10 mol/L 2pHCl-pHN3N150mmol/L510-9 mol/L 3Gly-Gly-HisMPACu2+ Cu2+ Cu2+ Cu2+pH210-10 mol/L
Resumo:
1758-3600m 6175826203200350035873600m22540185225 1.2251028452251010928 1604511745B1394873U/ml16SrDNAB1394Bacillus subtilis60pH 8.0 405060 Mn2+ Mg2+ Ca2+Hg2+ Fe3+ Cu2+ Zn2+ Fe2+PMSF 2.10040 Rhizoctonia solaniCandida albicans373537%35%1845%SHA6Fusarium oxysporum10SHA6, SHA6Aurantimonas altamirensis 3.205SHA4100g/ml83%,400ppm48h38%SHA4Nocardiopsis sp
Resumo:
TCASTCASTCASTCASPb2+Cd2+Cu2+Zn2+26.32mg•g-118.12mg•g-112.24mg•g-16.85mg•g-19.23 mg•g-17.92 mg•g-16.73 mg•g-14.34 mg•g-1pHTCASTCASTCASTCASTCASTCASTCASCuZnCdPblg9.798.726.875.00TCASTCAS
Resumo:
CuCuPCu2Freundiichcu2Cu2Cu2Freundllch-Cu2Cu2+Cu2+Cu2PP
Resumo:
81Z(MMO)81ZPO43-(>8mM),NH4+([NH4cl]>500mg/l)[CuSO45H2O]04mg/l[Cu2+][Cu2+](0.1mg/l CuSO45H2O)Cocl26H2O(0.238mg/l)81ZMMO81ZMMOMMO,MMOLPH6.26.44[Cu2+]-400M[Cu2+][Cu2+]81ZMMCPH7.04DE-52ABC81ZMMO[Cu2+]PH6.35mMMMO15.9nmol/minmg0.97nmol/minmgSome factors which influence growth and MMO activity of Methylosporovibrio methanica 81Z were described. The growth of Methylosporovibrio methanica 81Z is inhibited by high concentration of PO43-(8mM)or NH4+(500mg/lNH4cl). The growth of Methylosporovibrio methanica 81Z increased with rising of copper concentration up to 4mg/l CuSO45H2O. At low copper concentration(0.1mg/lCuSO45H2O),adding Cocl26H2O(0.238mg/l)could enhance the growth of Methylosporovibrio methanica 81Z.With batch culture of Methylosporovibrio methanica 81Z in a fermentor, after lag phase, the activity of MMO reached the highest level rapidly and steady until later log phase, then falled to initial level.MMOL activity differenct from that of two types of MMO reported before was found from Methylosporovibrio methanica 81Z with optimum PH value from 6.2 to 6.4 and relative stabilty at 4. Synthsis of the MMOL was not regulated by copper concentaration in medium. Its activity could couple with methane-l-methanoldehydrogenase system, and in cell-free extract, were inhibited by 400m copper ion. At low copper concentration(0.1mg/lCuSO45H2O) and in a fermentor, Methylosporovibrio methanica 81Z could syntheis soluble MMO similar to solble MMO reported before by Palton and Patel. Its optimum PH value was 7.0. It was unstable at 4. It could be resoluted into three components: A, B, and C. It was effentive for obtaining the maxtmum MMO with Methylosporovibrio methanica 81Z that (1) to keep high copper concentration(4mg/lCuSO45H2O) in a fermentor and harvest cell at middlel lag phase;(2) to choose 6.3 as the PH value of reaction buffer;(3)and to add 5mM methanol or formate into reaction system. In this dy, the MMO activity of cells of Methylosporovibrio methanica 81Z was reached 15.9 nmol/min.mg, dry weight, sixteen times as high as the value(0.97nmol/min.mg, dry weight) reported with the same strain.
Resumo:
A modified microfiltration membrane has been prepared by blending a matrix polymer with a functional polymer. Cellulose acetate (CA) was blended with polyethyleneimine (PEI), which was then crosslinked by polyisocyanate, in a mixture of solvents. In the membrane, PEI can supply coupling sites for ligands in affinity separation or be used as ligands for metal chelating, removal of endotoxin or ion exchange. The effects of the time of phase inversion induced by water vapor, blended amount of PEI and amount of crosslinking agent on membrane performance were investigated. The prepared blend membranes have specific surface area of 12.04-24.11 m(2)/g and pure water flux (PWF) of 10-50 ml/cm(2) min with porosity of 63-75%. The membranes, made of 0.15 50 wt.% PEI/CA ratio and 0.5 crosslinking agent/PEI ratio, were applied to adsorbing Cu2+ and bovine serum albumin (BSA) individually. The maximum adsorption capacity of Cu2+ ion on the blend membrane is 7.42 mg/g dry membrane. The maximum adsorption capacities of BSA on the membranes with and without chelating Cu2+ ion are 86.6 and 43.8 mg/g dry membrane, respectively. (C) 2004 Elsevier B.V. All rights reserved.
Resumo:
(CMC):(AA)/=10,()(N,N-)0.00140.0015.,CMC400~45016h,Zn2+Cu2+Pb2+Cd2+Cr2+Ni2+Mn2+.,CMC,pH,pH9;CMCPb2+Cu2+.
Resumo:
Cu5102550100mgL-1,Cu:,Cu25100mgL-1,(P<0.05),05mgL-1,Cu,10100mgL-1,Cu2+;aba+bCu10100mgL-1,(P<0.05)Cu;:>>>>>>,Cu,Cu
