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1.
The ability of trout to metabolize aniline in vitro in the presence of some divalent metal ions was investigated in the liver microsomes of rainbow trout, Salmo gairdneri. Trout liver microsomes were highly capable of catalyzing aniline hydroxylation to p-aminophenol with a specific activity of 0.068 nmoles/min per mg of microsomal protein in potassium phosphate buffer, pH 7.4 at 25°C. The activity of the aniline hydroxylase system was competitively inhibited by Hg +2, Ni +2, Cd +2, and Zn +2, while Cu +2 and Fe +3 seemed to inhibit the activity noncompetitively at 1 mM aniline concentrations. IC 50 values at fixed aniline concentration were estimated to be 0.45 mM for Hg +2, Ni +2, and Cd +2, 1.8 mM for Zn +2 and Fe +3, and 1.3 mM for Cu +2. Eadie-Hofstee plots gave identical V max values of approximately 0.046 nmol/min per mg of protein while K m values were increased in the presence of Hg +2, Ni +2, CD +2, and Zn +2, indicating competitive inhibition. Both K m and V max values were affected by Fe +3 and Cu +2, suggesting noncompetitive inhibition. K i values extracted from the Dixon plots were determined t be 0.23, 0.43, and 0.65 mM for Hg +2, Ni +2, and Cd +2, respectively, providing the most effective inhibition on the aniline hydroxylase system among studied metal ions. The K i values were much higher in the presence of others. The results indicate a selective inhibition of the aniline hydroxylase system of trout liver microsomes by divalent metal ions. © 1997 John Wiley & Sons, Inc. 相似文献
2.
Human serum albumin (HSA) has been shown to bind 2–3 mol of Zn 2+, Ni 2+, or Cd 2+ per mole of protein with apparent dissociation constants ( Kd) in the range of 10 μm. Rabbit histidine-rich glycoprotein (HRG) binds 13, 9, and 6 mol of Zn 2+, Ni 2+, and Cd 2+ per mole of protein, respectively, with apparent Kds also near 10 μm. However, the binding of metals by HRG exhibits positive cooperativity, so that the apparent Kds may underestimate HRGs true affinity for metal ions. The relative affinities of HSA and HRG for metal ions were found to be Zn 2+ > Ni 2+ > Cd 2+. In addition, histidine (a serum metal chelator) affected the binding of Ni 2+ by both proteins but not that of Zn 2+ or Cd 2+. At physiological concentrations of HSA (250 μm), HRG (2.5 μm), and histidine (100 μm), HRG bound 36% of the Zn 2+, 9% of the Ni 2+, and 13% of the Cd 2+ at a total metal concentration of 25 μm. Under the same conditions HSA held 37% of the Zn 2+, 14% of the Ni 2+, and 56% of the Cd 2+. Thus, HSA appears to have a lower intrinsic affinity for the three metals than HRG but would be expected to bind a higher proportion of these metals in serum. A specific immunoadsorbent column was prepared and used to study the metal binding by HRG in serum directly. Both 65Zn 2+ and 63Ni 2+ were associated with HRG in aliquots of rabbit serum after incubation with the corresponding metal ion. This evidence indicates that HRG must be considered as a metal binding component of serum. 相似文献
3.
Prokaryotic enzymes formamidopyrimidine-DNA glycosylase (Fpg) and endonuclease VIII (Nei) and their eukaryotic homologs NEIL1,
NEIL2, and NEIL3 define the Fpg family of DNA glycosylases, which initiate the process of repair of oxidized DNA bases. The
repair of oxidative DNA lesions is known to be impaired in vivo in the presence of ions of some heavy metals. We have studied the effect of salts of several alkaline earth and transition
metals on the activity of Fpg-family DNA glycosylases in the reaction of excision of 5,6-dihydrouracil, a typical DNA oxidation
product. The reaction catalyzed by NEIL1 was characterized by values K
m = 150 nM and k
cat = 1.2 min −1, which were in the range of these constants for excision of other damaged bases by this enzyme. NEIL1 was inhibited by Al 3+, Ni 2+, Co 2+, Cd 2+, Cu 2+, Zn 2+, and Fe 2+ in Tris-HCl buffer and by Cd 2+, Zn 2+, Cu 2+, and Fe 2+ in potassium phosphate buffer. Fpg and Nei, the prokaryotic homologs of NEIL1, were inhibited by the same metal ions as NEIL1.
The values of I 50 for NEIL1 inhibition were 7 μM for Cd 2+, 16 μM for Zn 2+, and 400 μM for Cu 2+. The inhibition of NEIL1 by Cd 2+, Zn 2+, and Cu 2+ was at least partly due to the formation of metal-DNA complexes. In the case of Cd 2+ and Cu 2+, which preferentially bind to DNA bases rather than phosphates, the presence of metal ions caused the enzyme to lose the
ability for preferential binding to damaged DNA. Therefore, the inhibition of NEIL1 activity in removal of oxidative lesions
by heavy metal ions may be a reason for their comutagenicity under oxidative stress. 相似文献
4.
The addition of as little as 2 ppb of manganese to ferrocyanide-treated beet molasses during citric acid fermentation by Aspergillus niger NRC A-1-233 caused a 10% reduction in acid yield and undesirable change in the morphology of the organism from the normal pelletlike form to the filamentous from. Still smaller additions (0.4-2ppb) caused undesirable pellet clumping, while greater additions (2-100 ppb) gave further decreases in yield. The yield obtained at 100 ppb was less than 25% of that obtained at 1 ppb or less. None of the other metals tested (Al 3+, Ca 2+, Co 2+, Cu 2+, Fe 2+, Mg 2+, Ni 2+, Zn 2+) visibly changed pellet morphology, and only Al 3+, Fe 2+, and Zn 2+ at relatively higher concentrations (5–25ppm) reduced acid yield. The adverse effect of manganese on growth and acid production was not affected by addition of the other metals. 相似文献
5.
Salts of Cu I, II, Ni II, Sn II, In III and a sub-fraction of the cupoprotein ceruloplasmin induced phagokinesis of cultured aortal endothelial cells. A variant aortal endothelial cell line was highly sensitive; cells travelled up to 1000 μm in 24 h in response to 2× 10 ?6 M SnCl 2. Other metal ions tested (Zn II, Co II, Mn II, Cr II, Fe III, Al III, Sb III and Mo II) were not active. The motility response of endothelial cells to Cu ions in vitro is proposed as a model system for studying early events in neovascularization and as a sensitive assay for detecting angiogenic activity in fractions from cells and tissues. 相似文献
6.
The toxicity of heavy metals on photosystem 2 photochemistry, was investigated by monitoring Hill activity, fluorescence, and thermoluminescence properties of photosystem 2 (PS 2) in pea ( Pisum sativum L. cv. Bombay) chloroplasts. In Co 2+-, Ni 2+- or Zn 2+-treated chloroplasts 2,6-dichlorophenolindophenol-Hill activity was markedly inhibited. Addition of hydroxylamine which donates electrons close to PS 2 reaction center did not restore the PS 2 activity. Co 2+-, Ni 2+ or Zn 2+ also inhibited PS 2 activity supported by hydroxylamine in tris (hydroxymethyl)aminomethane (Tris)-inactivated chloroplasts. These observations were confirmed by fluorescence transient measurements. This implies that the metal ions inhibit either the reaction center or the components of PS 2 acceptor side. Flash-induced thermoluminescence studies revealed that the S 2Q ?A charge recombination was insensitive to metal ion addition. The S 2Q ?B charge recombination, however, was inhibited with increase in the level of Co 2+, Ni 2+ or Zn 2+. The observed sensitivity of S 2?B charge recombination in comparison to the stability of S 2Q ?A recombination suggests that the metal ions inhibit at the level of secondary quinone electron acceptor. Q B. We suggest that Co 2+, Ni 2+ or Zn 2+ do not block the electron flow between the primary and secondary quinone electron acceptor, but possibly, directly modify Q B site, leading to the loss of PS 2 activity. 相似文献
7.
Complexes formed by reduced glutathione (GSH) with metal cations (Cr 2+, Mn 2+,Fe 2+,Co 2+,Ni 2+,Cu 2+,Zn 2+,Cd 2+,Hg 2+) were systematically investigated by the density functional theory (DFT). The results showed that the interactions of the metal cations with GSH resulted in nine different stable complexes and many factors had an effect on the binding energy. Generally, for the same period of metal ions, the binding energies ranked in the order of Cu 2+>Ni 2+>Co 2+>Fe 2+>Cr 2+>Zn 2+>Mn 2+; and for the same group of metal ions, the general trend of binding energies was Zn 2+>Hg 2+>Cd 2+. Moreover, the amounts of charge transferred from S or N to transition metal cations are greater than that of O atoms. For Fe 2+,Co 2+,Ni 2+,Cu 2+,Zn 2+,Cd 2+ and Hg 2+ complexes, the values of the Wiberg bond indices (WBIs) of M-S (M denotes metal cations) were larger than that of M-N and M-O; for Cr 2+ complexes, most of the WBIs of M-O in complexes were higher than that of M-S and M-N. Furthermore, the changes in the electron configuration of the metal cations before and after chelate reaction revealed that Cu 2+, Ni 2+,Co 2+ and Hg 2+ had obvious tendencies to be reduced to Cu +,Ni +,Co + and Hg + during the coordination process. 相似文献
8.
Yersiniabactin (Ybt) is a metal‐binding natural product that has been re‐purposed for water treatment. The early focus of this study was the characterization of metal binding breadth attributed to Ybt. Using LC‐MS analysis of water samples exposed to aqueous and surface‐localized Ybt, quantitative assessment of binding was completed with metals that included Pd 2+, Mg 2+, and Zn 2+. In total, Ybt showed affinity for 10 metals. Next, Ybt‐modified XAD‐16N resin (Ybt‐XAD) was utilized to quantify the affinity for metal removal, showing a rank order of Fe 3+ > Ga 3+ > Ni 2+ > Cu 2+ > Cr 2+≈Zn 2+ > Co 2+ > Pd 2+ > Mg 2+ > Al 3+, and in the applied treatment of wastewater from a local precious metal plating company, showing selective removal of nickel from the aqueous effluent. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1548–1554, 2017 相似文献
9.
The present work deals with the biosorption performance of dried and non-growing biomasses of Exiguobacterium sp. ZM-2, isolated from soil contaminated with tannery effluents, for the removal of Cd 2+, Ni 2+, Cu 2+, and Zn 2+ from aqueous solution. The metal concentrations studied were 25 mg/l, 50 mg/l, 100 mg/l, 150 mg/l and 200 mg/l. The effect of solution pH and contact time was also studied. The biosorption capacity was significantly altered by pH of the solution. The removal of metal ions was conspicuously rapid; most of the total sorption occurred within 30 min. The sorption data have been analyzed and fitted to the Langmuir and Freundlich isotherm models. The highest Q max value was found for the biosorption of Cd 2+ at 43.5 mg/g in the presence of the non-growing biomass. Recovery of metals (Cd 2+, Zn 2+, Cu 2+ and Ni 2+) was found to be better when dried biomass was used in comparison to non-growing biomass. Metal removal through bioaccumulation was determined by growing the bacterial strain in nutrient broth amended with different concentrations of metal ions. This multi-metal resistant isolate could be employed for the removal of heavy metals from spent industrial effluents before discharging them into the environment. 相似文献
10.
Despite technological developments and improved liner-material applications, heavy metals in landfill leachate still penetrate the soil profile, polluting the soil and ground-water. An alternative approach therefore must be explored to reduce heavy-metal migration in soil-bentonite landfill liners. By considering the interaction of different heavy metals and their synergetic and antagonistics behaviors, such an approach could be developed. Low mobility metals such as Cu 2+, and Pb 2+ inhibit the adsorption of Cd 2+ which is a moderate-mobility metal and Cu 2+ sorption is decreased by the presence of Zn 2+ and Cd 2+. Therefore, Zn 2+, a low-mobility metal, cannot be grouped with Cu 2+. This way, four compatible metal groups have been identified: (1) low mobility: Pb 2+, Cu 2+, and Ag, (2) low mobility: Zn 2+ and Cr 3+; (3) moderate mobility: As 2+, Fe 2+, and Ni 2+; (4) high mobility: Cd 2+ and Hg 2+. Cd 2+ with a moderate mobility pattern is synergetic to Fe 2+ and is more mobile with Ni 2+. Therefore, Cd 2+ is separated from the moderate-mobility group and is consigned with Hg, a high-mobility metal. The liner materials suitable for Hg 2+ are assumed to be suitable for Cd 2+ as well. Based on this concept, and to reduce heavy metal mobility, wastes should be segregated on compatibility basis according to their heavy metal contents before being disposed in different individual compartments. For wastes containing several incompatible heavy metals, sorting should be based on the heavy-metal with the highest concentration. Another solution is the manufacturing of products using compatible heavy metal combinations and then labeling them accordingly. Such waste segregation and landfill compartmentalization lowers risks of groundwater contamination and liner cost. 相似文献
11.
Summary The bioaccumulation of metals (Cu 2+, Cr 6+, Cd 2+, Ni 2+ and Zn 2+) from three electroplating effluents by viable Saccharomyces cerevisiae, and the effect of glucose treatment on accumulation was determined. Pretreatment of the yeast cells with glucose increased the amount of metal removed, whilst direct addition of glucose to the yeast-effluent solution had no effect on the amount of metal accumulated. 相似文献
12.
Effects of heavy metals on the isopod Asellus aquaticus (L.) are studied by static toxicity tests. Results demonstrate that the species is sensitive to Cd +2, Cr +6, Cu +2, Fe +3, Hg +2, Ni +2 Pb +2 and Zn +2, but the toxicity of each metal is different. Differences are also found between adults and between adults and juveniles. The comparative analysis of all data on the toxicity has been performed on the concentrations of metal ions and not on metal compound concentrations.Criteria for establishing water quality in order to guarantee protection of the environment are discussed. 相似文献
13.
This paper reports the synthesis of azomethine-modified gold nanoparticles with azomethine (azomethine-AuNPs) in aqueous media, which were characterized by FT-IR spectroscopy, ultraviolet–visible spectroscopy (UV-Vis), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The azomethine-AuNPs were employed as colorimetric for Cr3+ and Co2+ ions at pH 6.2–7.5 and 8.1–9.1, at room temperature in aqueous solution. In the presence of Cr3+ and Co2+, the azomethine-AuNPs induce aggregation of the nanoparticles. Upon aggregation, the surface plasmon absorption band red-shifts so that the nanoparticle solution appears a blue color. The sensitivity of azomethine-AuNPs towards other metal ions, Mg2+, Mn2+, Cr6+, Na+, Ni2+, Ag+, Al3+, Ca2+, Cd2+, Cu2+, Fe2+, Fe3+, Hg2+, Cd2+, K+, Co3+, Ni2+, Pb2+, and Zn2+ are negligible. This highly selective sensor allows a direct quantitative assay of Co2+ and Cr3+ with colorimetric detection limits of 83.22 and 108 nM, respectively. 相似文献
14.
In this study, we fabricated a novel recycled aggregate (RA) bio-carrier with sulfate-reducing bacteria (SRB) for the effective removal of the heavy metals Zn 2+, Ni 2+, and Cr 6+ from contaminated seawater. By using only RA carriers, Zn 2+, Ni 2+, and Cr 6+ could be removed up to 35.6, 11.0, and 61.3% and SRB-immobilized RA biocarriers could effectively lead to the removal of Zn 2+, Ni 2+, and Cr 6+ up to 100.0, 98.0, and 87.8% for 100 ppm concentration of the heavy metals at 37°C, respectively. These results indicate that recycled aggregate bio-carriers with SRB hold great potential for use in the removal of cationic heavy metal species from marine environment. 相似文献
15.
Industrial wastewaters polluted with toxic heavy metals are serious ecological and environmental problem. Therefore, in this
study multi-heavy metals (Fe 2+, Cu 2+, Ni 2+ and Zn 2+) removal process with mixed microbial culture was examined in the horizontal rotating tubular bioreactor (HRTB) by different
combinations of process parameters. Hydrodynamic conditions and biomass sorption capacity have main impact on the removal
efficiency of heavy metals: Fe 2+ 95.5–79.0%, Ni 2+ 92.7–54.8%, Cu 2+ 87.7–54.9% and Zn 2+ 81.8–38.1%, respectively. On the basis of experimental results, integral mathematical model of removal heavy metals in the
HRTB was established. It combines hydrodynamics (mixing), mass transfer and kinetics to define bioprocess conduction in the
HRTB. Mixing in the HRTB was described by structured cascade model and metal ion removal by two combined diffusion–adsorption
models, respectively. For Langmuir model, average variances between experimental and simulated concentrations of metal ions
were in the range of 1.22–10.99 × 10 −3 and for the Freundlich model 0.12–3.98 × 10 −3, respectively. On the basis of previous facts, it is clear that developed integral bioprocess model with Freundlich model
is more efficient in the prediction of concentration of metal ions in the HRTB. Furthermore, the results obtained also pointed
out that the established model is at the same time accurate and robust and therefore it has great potential for use in the
scale-up procedure. 相似文献
16.
The authors report that a marine Shewanella sp. CNZ-1 is capable of producing Au NPs under various conditions. Results showed that initial concentration of Au(III), pH values and electron donors affected nucleation of Au NPs by CNZ-1, resulting in different apparent color of the as-obtained bio-Au NPs, which were further characterized by UV-Vis, TEM, XRD, and XPS analyses. Mechanism studies revealed that Au(III) was first reduced to Au(I) and eventually reduced to EPS-coated Au 0 NPs. FTIR and FEEM analyses revealed that some amides and humic acid-like matters were involved in the production of bio-Au NPs through CNZ-1 cells. In addition, the authors also found that the catalytic activity of bio-Au NPs for 4-nitrophenol (4-NP) reduction could be enhanced by various metal ions (Ca 2+, Cu 2+, Co 2+, Fe 2+, Fe 3+, Ni 2+, Sr 2+, and Cr 3+) and metal oxides (Fe 3O 4, Al 2O 3, and SiO 2), which is beneficial for their further practical application. The maximum zero-order rate constant k 1 and first-order rate constant k2 of all metal ions/oxides supplemented systems can reach 99.65 mg/(L .min) and 2.419 min −1, which are 11.3- and 12.6-fold higher than that of control systems, respectively. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2727, 2019. 相似文献
17.
Three new chiral ligands bearing an O,O′,N donor set (O methoxyO hydroxyN pyridine) were synthesised and coordinated to Fe III, Fe II, Ni II, Cu II and Zn II to yield complexes with the general formula [M(OON)Cl x] y. While the pyridine N and the hydroxy O atoms coordinate strongly to all applied metal ions, the methoxy donor seems not to be involved in coordination, although some evidence for a weak interaction between O Me and the Zn II were found in NMR spectra. In the bidentate O′,N coordination mode the new ligands exhibit several coordination geometries as analysed in the solid compounds by XRD, EXAFS and EPR and in solution by UV-Vis absorption, cyclic voltammetry, EXAFS, EPR or NMR spectroscopy. 相似文献
18.
Triethyl thiophosphate (tetp) invariably forms adducts with various metal perchlorates (M=Mg 2+, Al 3+, Cr 3+, Mn 2+, Fe 2+, Fe 3+, Co 2+, Ni 2+, Cu 2+, Zn 2+, Cd 2+) at 35–40°C in ethanol-triethyl orthoformate (teof). Only certain of these adducts, which involve S-bonded tetp in the thione form for soft or borderline metal ions and O-bonded tetp in the thiol tautomeric form for hard metal ions, could be isolated in solid form, owing to their tendency to decompose yielding diethylthiophosphato (detp) metal complexes and ethyl perchlorate, at temperatures ranging between ambient and 80–90°C, depending on the metal ion. Several well-defined detp and detpperchlorato metal complexes were obtained by heating solutions of mixtures of tetp and metal perchlorates in ethanol-teof at 80–90°C, and characterized. In most cases, linear polymeric or dimeric complexes involving double or triple bridges of O,S-bonded bidentate detp between adjacent metal ions were isolated. However, in a number of occasions, heavily hydrated monomeric species, containing terminal S-bonded detp were obtained. 相似文献
20.
By combining two functions of alginate gel and activated carbon, an activated carbon-containing alginate bead (AC-AB) adsorbent was developed and successfully used to simultaneously remove heavy metal ions and toxic organics. Quantitative analysis showed that almost all of the adsorption of toxic organics, such as p-toluic acid, is caused by the activated carbon in the AC-AB adsorbent, whereas the alginate component has a major role in the removal of heavy metals. A 50-L solution containing eight heavy metals (Pb 2+, Mn 2+, Cd 2+, Cu 2+, Zn 2+, Fe 2+, Al 3+ and Hg 2+) and four mineral ions was run continuously through a filter cartridge packed with 160 g of the AC-AB adsorbent. The adsorbent showed a high capacity to remove heavy metals completely from the water, while allowing essential minerals, such as K +, Na +, Mg 2+ and Ca 2+, to pass through the filter. The adsorbent could be regenerated using eluents, such as HNO 3, and reused repeatedly without considerable loss of its metal uptake capacity through 10 subsequent cycles of adsorption and desorption. With its high capacity and high selectivity for toxic heavy metals, the AC-AB adsorbent has enormous potential for application in drinking water treatment technologies. 相似文献
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