Journal articles: 'Metal ion uptake'

1

Banat, Fawzi, Sameer Al-Asheh, and Dheaya‘ Al-Rousan. "Comparison between Different Keratin-composed Biosorbents for the Removal of Heavy Metal Ions from Aqueous Solutions." Adsorption Science & Technology 20, no. 4 (2002): 393–416. http://dx.doi.org/10.1260/02636170260295579.

Full text

Abstract:

This study examined and compared the ability of chicken feathers, human hair and animal horns, as keratin-composed biosorbents, for the removal of Zn2+ and Cu2+ ions from single metal ion aqueous solutions under different operating conditions. The three biosorbents investigated in this study were all capable of adsorbing Zn2+ and Cu2+ ions from aqueous solutions. The biosorbent showing the highest uptake of Zn2+ and Cu2+ ions was animal horns. Chicken feathers showed a higher Cu2+ ion uptake and a lower Zn2+ ion compared to human hair. Increasing the initial concentration of Zn2+ or Cu2+ ions, or increasing the initial pH value, increased the metal ion uptake. Such uptake decreased when the temperature was raised from 25°C to 50°C for all adsorbent/metal ion combinations except for Zn2+ ion/human hair where the uptake increased with temperature. It was demonstrated that the addition of NaCl salt to the metal ion solution depressed the metal ion uptake. The Freundlich isotherm model was found to be applicable to the adsorption data for Cu2+ and Zn2+ ions.

APA, Harvard, Vancouver, ISO, and other styles

2

Degryse, Fien, Erik Smolders, and David R. Parker. "An Agar Gel Technique Demonstrates Diffusion Limitations to Cadmium Uptake by Higher Plants." Environmental Chemistry 3, no. 6 (2006): 419. http://dx.doi.org/10.1071/en06057.

Full text

Abstract:

Environmental Context. Toxic effects of trace metals are often related to the amount of metal that is internalized by the organism. Uptake of metals by biota is usually predicted with equilibrium models, which assume that transport of the metal from the solution to the biosurface does not limit uptake. In this study, uptake of cadmium by higher plants is shown to be limited by the transport of the free ions to the root surface under a range of conditions. Abstract. Uptake of cadmium (Cd) by spinach and wheat was higher in the presence of fast-dissociating complexes than in unbuffered solutions with the same free ion concentration. This contribution of metal complexes to metal uptake cannot be explained by equilibrium free-ion-based models, which assume that transport of the free ion to the biosurface is not limiting the uptake. To demonstrate diffusion limitations to metal uptake, we used an agar gel technique in which Cd and Zn concentrations around the roots, after 6 h of uptake, were compared with bulk concentrations. Metal depletion around the roots was clearly observed in agar where the ion activities were not buffered by complexes, whereas the depletion was less pronounced in buffered agar. Metal uptake by the plants in unbuffered media was greater as the degree of agitation increased (stirred solution > unstirred solution > agar), while no such dependence on hydrodynamic conditions was found in buffered media, which is in agreement with theoretical predictions.

APA, Harvard, Vancouver, ISO, and other styles

3

Krom, Bastiaan P., Jessica B. Warner, Wil N. Konings, and Juke S. Lolkema. "Complementary Metal Ion Specificity of the Metal-Citrate Transporters CitM and CitH of Bacillus subtilis." Journal of Bacteriology 182, no. 22 (2000): 6374–81. http://dx.doi.org/10.1128/jb.182.22.6374-6381.2000.

Full text

Abstract:

ABSTRACT Citrate uptake in Bacillus subtilis is stimulated by a wide range of divalent metal ions. The metal ions were separated into two groups based on the expression pattern of the uptake system. The two groups correlated with the metal ion specificity of two homologousB. subtilis secondary citrate transporters, CitM and CitH, upon expression in Escherichia coli. CitM transported citrate in complex with Mg2+, Ni2+, Mn2+, Co2+, and Zn2+ but not in complex with Ca2+, Ba2+, and Sr2+. CitH transported citrate in complex with Ca2+, Ba2+, and Sr2+ but not in complex with Mg2+, Ni2+, Mn2+, Co2+, and Zn2+. Both transporters did not transport free citrate. Nevertheless, free citrate uptake could be demonstrated in B. subtilis, indicating the expression of at least a third citrate transporter, whose identity is not known. For both the CitM and CitH transporters it was demonstrated that the metal ion promoted citrate uptake and, vice versa, that citrate promoted uptake of the metal ion, indicating that the complex is the transported species. The results indicate that CitM and CitH are secondary transporters that transport complexes of divalent metal ions and citrate but with a complementary metal ion specificity. The potential physiological function of the two transporters is discussed.

APA, Harvard, Vancouver, ISO, and other styles

4

Sacher, A., A. Cohen, and N. Nelson. "Properties of the mammalian and yeast metal-ion transporters DCT1 and Smf1p expressed in Xenopus laevis oocytes." Journal of Experimental Biology 204, no. 6 (2001): 1053–61. http://dx.doi.org/10.1242/jeb.204.6.1053.

Full text

Abstract:

Transition metals are essential for many metabolic processes, and their homeostasis is crucial for life. Metal-ion transporters play a major role in maintaining the correct concentrations of the various metal ions in living cells. Little is known about the transport mechanism of metal ions by eukaryotic cells. Some insight has been gained from studies of the mammalian transporter DCT1 and the yeast transporter Smf1p by following the uptake of various metal ions and from electrophysiological experiments using Xenopus laevis oocytes injected with RNA copies (c-RNA) of the genes for these transporters. Both transporters catalyze the proton-dependent uptake of divalent cations accompanied by a ‘slippage’ phenomenon of different monovalent cations unique to each transporter. Here, we further characterize the transport activity of DCT1 and Smf1p, their substrate specificity and their transport properties. We observed that Zn(2+) is not transported through the membrane of Xenopus laevis oocytes by either transporter, even though it inhibits the transport of the other metal ions and enables protons to ‘slip’ through the DCT1 transporter. A special construct (Smf1p-s) was made to enhance Smf1p activity in oocytes to enable electrophysiological studies of Smf1p-s-expressing cells. 54Mn(2+) uptake by Smf1p-s was measured at various holding potentials. In the absence of Na(+) and at pH 5.5, metal-ion uptake was not affected by changes in negative holding potentials. Elevating the pH of the medium to 6.5 caused metal-ion uptake to be influenced by the holding potential: ion uptake increased when the potential was lowered. Na(+) inhibited metal-ion uptake in accordance with the elevation of the holding potential. A novel clutch mechanism of ion slippage that operates via continuously variable stoichiometry between the driving-force pathway (H(+)) and the transport pathway (divalent metal ions) is proposed. The possible physiological advantages of proton slippage through DCT1 and of Na(+) slippage through Smf1p are discussed.

APA, Harvard, Vancouver, ISO, and other styles

5

Rao, B. K., and P. Jena. "Hydrogen Uptake by an Alkali Metal Ion." Europhysics Letters (EPL) 20, no. 4 (1992): 307–12. http://dx.doi.org/10.1209/0295-5075/20/4/004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

S.C., Das. "Ion-exchange studies of resin copolymers derived from aromatic hydroxy compounds." Journal of Indian Chemical Society Vol. 77, Feb 2000 (2000): 66–69. https://doi.org/10.5281/zenodo.5862154.

Full text

Abstract:

Department of Chemistry, S. V. M. College, Jagatsinghpur-754 103, India Manuscript received 18 September 1998, revised 22 June 1999, accepted 20 August 1999 The ion-exchange capacity, effect of electrolytes on metal uptake, rate of metal uptake and distribution of metal ion at different pHs of resin copolymers derived from thiosemicarbazone derivatives of phenolic compounds shows higher order than the resin copolymer derived from semicarbazone derivatives. The results are compared with the commercial ion-exchangers.

APA, Harvard, Vancouver, ISO, and other styles

7

Degryse, Fien, and Erik Smolders. "Cadmium and nickel uptake by tomato and spinach seedlings: plant or transport control?" Environmental Chemistry 9, no. 1 (2012): 48. http://dx.doi.org/10.1071/en11060.

Full text

Abstract:

Environmental contextUptake of metal ions by plants is often predicted with equilibrium models, which assume that the rate limiting step is trans-membrane uptake of the metal in the roots rather than the transport of the metal ion towards the site of uptake. Evidence is given that uptake of cadmium by plants is under strong transport control at environmentally relevant concentrations, whereas nickel uptake borders between transport and plant control. This explains the lack of ion competition effects for Cd uptake, whereas both proton and Mg ions were found to compete with Ni uptake. AbstractEquilibrium models for metal uptake by biota assume that the uptake is rate limited by the internalisation of the metal across the cell membrane (plant control). However, evidence has been found that Cd uptake by plants is controlled by the diffusive transport of the free ion to the root at low Cd2+ activities. In this study, the uptake of Cd and Ni by tomato and spinach in nutrient solution was compared to assess whether Ni uptake is under plant or transport control. The diffusive gradient in thin films (DGT) technique was used to measure the maximal diffusive flux. In unbuffered solutions, the uptake flux of Ni was approximately three-fold smaller than that of Cd at free ion concentrations below 1 µM. Stirring the solution increased the uptake of Cd, but not that of Ni at low free ion concentration. The presence of DGT-labile complexes increased the uptake of Cd, but not that of Ni, except at high pH (pH 7). Increasing the solution pH increased Cd uptake only when solution Cd2+ activities were strongly buffered. Overall, the results indicated that the Cd uptake was strongly diffusion limited and that uptake is likely to be under transport control in natural environments. Uptake of nickel, on the other hand, appears to be at the border between plant and transport control. This finding has practical applications, e.g. competition effects at the root have little effect on Cd uptake and chelator-assisted phytoextraction is expected to have less effect for Ni than for Cd.

APA, Harvard, Vancouver, ISO, and other styles

8

Drake, Lawrence R., Carl E. Hensman, Shan Lin, Gary D. Rayson, and Paul J. Jackson. "Characterization of Metal Ion Binding Sites on Datura Innoxia by Using Lanthanide Ion Probe Spectroscopy." Applied Spectroscopy 51, no. 10 (1997): 1476–83. http://dx.doi.org/10.1366/0003702971939253.

Full text

Abstract:

The excitation spectra associated with the 7F0↦5D0 transition of Eu+3 has been used to examine the binding sites on cell wall fragments of Datura innoxia. Both native and esterified cell wall fragments were each examined at pH 5 and pH 2 to determine the contributions to metal ion sorption from both the carboxylate and sulfonate functional groups. The excitation spectra have been de-convoluted into the individual groups responsible for metal ion uptake. At least four unique binding sites can be described as being responsible for metal ion uptake. The higher affinity sites involve carboxylates in the binding of Eu+3 in a tridentate (3:1 ligand-to-metal ratio) configuration.

APA, Harvard, Vancouver, ISO, and other styles

9

Al-Asheh, Sameer, Fawzi Banat, and Dheaya‘ Al-Rousan. "Adsorption of Copper, Zinc and Nickel Ions from Single and Binary Metal Ion Mixtures on to Chicken Feathers." Adsorption Science & Technology 20, no. 9 (2002): 849–64. http://dx.doi.org/10.1260/02636170260555778.

Full text

Abstract:

Certain industries often produce mixtures of heavy metal ions in their waste products. Because of the nature of heavy metal ions and the adsorption process, such metal ions can compete with each other for the sorption sites on an adsorbent during adsorption processes. In the present work, binary systems composed of copper, zinc and nickel ions were selected as examples of heavy metal ion mixtures and tested via batch adsorption processes using chicken feathers as an adsorbent. The uptake of individual metal ions was depressed by the presence of another. Thus, the uptake of copper ions from an initial copper ion solution of 20 ppm concentration was reduced from 0.042 mmol/g to ca. 0.019 mmol/g by the presence of a similar concentration of nickel ions. The Freundlich, Langmuir and Sips multi-component adsorption models were employed to predict the uptake of metal ions from binary metal ion solutions using constants obtained from adsorption isotherm models applied to single-solute systems.

APA, Harvard, Vancouver, ISO, and other styles

10

Rivas, Bernabé L., S. Amalia Pooley, Hernán A. Maturana, and Sandra Villegas. "Metal Ion Uptake Properties of Acrylamide Derivative Resins." Macromolecular Chemistry and Physics 202, no. 3 (2001): 443–47. http://dx.doi.org/10.1002/1521-3935(20010201)202:3<443::aid-macp443>3.0.co;2-f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Bhardwaj, Nikita, Mohd Tashfeen Ashraf, and Jaya Maitra. "Heavy metal ion uptake using biodegradable polymeric film." Brazilian Journal of Development 10, no. 1 (2024): 965–77. http://dx.doi.org/10.34117/bjdv10n1-063.

Full text

Abstract:

This study investigates the potential of gelatin films as a biodegradable material for food preservation and heavy metal ion removal. Gelatin, a biodegradable protein derived from animal collagen, was dissolved in distilled water to form a solution and casted to form films. The films were evaluated for their swelling behavior, solubility in food, moisture content, thickness, and biodegradability. The results showed that gelatin films were completely soluble in water within 3 hours, with a water solubility of 29 ± 1.6%. The films showed UV-visible light absorbance ranging from 280 to 480 nm with maximum absorbance at 420 nm. The films were also found to have a high potential for heavy metal ion removal, specifically for copper (II) and zinc (II) ions. The films were able to effectively remove these ions from aqueous solutions under acidic conditions, with removal efficiencies of 99.3% and 97.3%, respectively. The findings suggest that gelatin films could be a promising material for sustainable food packaging and for removing heavy metals from wastewater.

APA, Harvard, Vancouver, ISO, and other styles

12

Lensbouer, Joshua J., Ami Patel, Joseph P. Sirianni, and Robert P. Doyle. "Functional Characterization and Metal Ion Specificity of the Metal-Citrate Complex Transporter from Streptomyces coelicolor." Journal of Bacteriology 190, no. 16 (2008): 5616–23. http://dx.doi.org/10.1128/jb.00456-08.

Full text

Abstract:

ABSTRACT Secondary transporters of citrate in complex with metal ions belong to the bacterial CitMHS family, about which little is known. The transport of metal-citrate complexes in Streptomyces coelicolor has been investigated. The best cofactor for citrate uptake in Streptomyces coelicolor is Fe3+, but uptake was also noted for Ca2+, Pb2+, Ba2+, and Mn2+. Uptake was not observed with the Mg2+, Ni2+, or Co2+ cofactor. The transportation of iron- and calcium-citrate makes these systems unique among the CitMHS family members reported to date. No complementary uptake akin to that observed for the CitH (Ca2+, Ba2+, Sr2+) and CitM (Mg2+, Ni2+, Mn2+, Co2+, Zn2+) systems of Bacillus subtilis was noted. Competitive experiments using EGTA confirmed that metal-citrate complex formation promoted citrate uptake. Uptake of free citrate was not observed. The open reading frame postulated as being responsible for the metal-citrate transport observed in Streptomyces coelicolor was cloned and overexpressed in Escherichia coli strains with the primary Fe3+-citrate transport system (fecABCDE) removed. Functional expression was successful, with uptake of Ca2+-citrate, Fe3+-citrate, and Pb2+-citrate observed. No free-citrate transport was observed in IPTG (isopropyl-β-d-thiogalactopyranoside)-induced or -uninduced E. coli. Metabolism of the Fe3+-citrate and Ca2+-citrate complexes, but not the Pb2+-citrate complex, was observed. Rationalization is based on the difference in metal-complex coordination upon binding of the metal by citrate.

APA, Harvard, Vancouver, ISO, and other styles

13

Pinilla-Tenas, Jorge J., Brian K. Sparkman, Ali Shawki, et al. "Zip14 is a complex broad-scope metal-ion transporter whose functional properties support roles in the cellular uptake of zinc and nontransferrin-bound iron." American Journal of Physiology-Cell Physiology 301, no. 4 (2011): C862—C871. http://dx.doi.org/10.1152/ajpcell.00479.2010.

Full text

Abstract:

Recent studies have shown that overexpression of the transmembrane protein Zrt- and Irt-like protein 14 (Zip14) stimulates the cellular uptake of zinc and nontransferrin-bound iron (NTBI). Here, we directly tested the hypothesis that Zip14 transports free zinc, iron, and other metal ions by using the Xenopus laevis oocyte heterologous expression system, and use of this approach also allowed us to characterize the functional properties of Zip14. Expression of mouse Zip14 in RNA-injected oocytes stimulated the uptake of 55Fe in the presence of l-ascorbate but not nitrilotriacetic acid, indicating that Zip14 is an iron transporter specific for ferrous ion (Fe2+) over ferric ion (Fe3+). Zip14-mediated 55Fe2+ uptake was saturable ( K0.5 ≈ 2 μM), temperature-dependent (apparent activation energy, Ea = 15 kcal/mol), pH-sensitive, Ca2+-dependent, and inhibited by Co2+, Mn2+, and Zn2+. HCO3− stimulated 55Fe2+ transport. These properties are in close agreement with those of NTBI uptake in the perfused rat liver and in isolated hepatocytes reported in the literature. Zip14 also mediated the uptake of 109Cd2+, 54Mn2+, and 65Zn2+ but not 64Cu (I or II). 65Zn2+ uptake also was saturable ( K0.5 ≈ 2 μM) but, notably, the metal-ion inhibition profile and Ca2+ dependence of Zn2+ transport differed from those of Fe2+ transport, and we propose a model to account for these observations. Our data reveal that Zip14 is a complex, broad-scope metal-ion transporter. Whereas zinc appears to be a preferred substrate under normal conditions, we found that Zip14 is capable of mediating cellular uptake of NTBI characteristic of iron-overload conditions.

APA, Harvard, Vancouver, ISO, and other styles

14

Mandal, Suraj Kumar, and Shankar Prasad Kanaujia. "Structural and thermodynamic insights into a novel Mg²⁺–citrate-binding protein from the ABC transporter superfamily." Acta Crystallographica Section D Structural Biology 77, no. 12 (2021): 1516–34. http://dx.doi.org/10.1107/s2059798321010457.

Full text

Abstract:

More than one third of proteins require metal ions to accomplish their functions, making them obligatory for the growth and survival of microorganisms in varying environmental niches. In prokaryotes, besides their involvement in various cellular and physiological processes, metal ions stimulate the uptake of citrate molecules. Citrate is a source of carbon and energy and is reported to be transported by secondary transporters. In Gram-positive bacteria, citrate molecules are transported in complex with divalent metal ions, whereas in Gram-negative bacteria they are translocated by Na+/citrate symporters. In this study, the presence of a novel divalent-metal-ion-complexed citrate-uptake system that belongs to the primary active ABC transporter superfamily is reported. For uptake, the metal-ion-complexed citrate molecules are sequestered by substrate-binding proteins (SBPs) and transferred to transmembrane domains for their transport. This study reports crystal structures of an Mg2+–citrate-binding protein (MctA) from the Gram-negative thermophilic bacterium Thermus thermophilus HB8 in both apo and holo forms in the resolution range 1.63–2.50 Å. Despite binding various divalent metal ions, MctA possesses the coordination geometry to bind its physiological metal ion, Mg2+. The results also suggest an extended subclassification of cluster D SBPs, which are known to bind and transport divalent-metal-ion-complexed citrate molecules. Comparative assessment of the open and closed conformations of the wild-type and mutant MctA proteins suggests a gating mechanism of ligand entry following an `asymmetric domain movement' of the N-terminal domain for substrate binding.

APA, Harvard, Vancouver, ISO, and other styles

15

Watkins, Barbara, and K. Simkiss. "The effect of oscillating temperatures on the metal ion metabolism of Mytilus edulis." Journal of the Marine Biological Association of the United Kingdom 68, no. 1 (1988): 93–100. http://dx.doi.org/10.1017/s0025315400050128.

Full text

Abstract:

The effect of increasing the temperature of Mytilus edulis by 10 °C is to increase the rate of 65Zn uptake. If the temperature is oscillated through this range there is a further enhancement of metal uptake. The effect is associated with a decrease in cytosol metal and an increase in granular fractions. These unexpected results are interpreted in terms of cellular metal-ligand homeostasis.

APA, Harvard, Vancouver, ISO, and other styles

16

Rivas, Bernabé L., Julio Sánchez, and Bruno F. Urbano. "Polymers and nanocomposites: synthesis and metal ion pollutant uptake." Polymer International 65, no. 3 (2015): 255–67. http://dx.doi.org/10.1002/pi.5035.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Nies, D. H., and S. Silver. "Metal ion uptake by a plasmid-free metal-sensitive Alcaligenes eutrophus strain." Journal of Bacteriology 171, no. 7 (1989): 4073–75. http://dx.doi.org/10.1128/jb.171.7.4073-4075.1989.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Alcantara, Rochelle T., Dahlia C. Apodaca, and Manuel R. De Guzman. "The Effect of the Presence of Cu2+ and Fe3+ Metal Ions on the Sorption of Mercuric Ion (Hg2+) by Sargassum cristaefolium." ASEAN Journal of Chemical Engineering 7, no. 1 & 2 (2007): 147. http://dx.doi.org/10.22146/ajche.50138.

Full text

Abstract:

Previous studies have indicated that the seaweed Sargassum cristaefolium is capable of binding with metal ions. The metal sorbing property of S. cristaefolium suggests its possible participation in the removal of Hg2+ ions in water and wastewater. However, the potential application of S. cristaefolium for environmental remediation and precious metals recovery depends on the understanding of the other factors that could play a role in the sorption process. This study illustrates the effects of some variables, such as pH and temperature, and that of the presence of other metal ions on the sorption process involving the binding of Hg2+ ions to S. cristaefolium. The uptake of Hg2+ ion was found to be affected by the initial concentration and the charge densities of the competing ions. Cu2+ ion shows a stronger affinity to Sargassum in the three metal systems of Hg2+, Cu2+, and Fe3+ ions. On the other hand, results show that Fe3+ ion is not a potential competitor for binding sites considering that no Fe3+ ion uptake by Sargassum has been observed.

APA, Harvard, Vancouver, ISO, and other styles

19

Ramyakrishna, K., and M. Sudhamani. "The metal binding potential of a dairy isolate." Journal of Water Reuse and Desalination 7, no. 4 (2016): 429–41. http://dx.doi.org/10.2166/wrd.2016.127.

Full text

Abstract:

Excess iron in water resources can lead to health hazards and problems. The ability of lactic acid bacteria to bind iron has not yet been widely studied. In the present study, sorption of iron ions from aqueous solutions onto lactic acid bacterium was determined. Elemental analyses were carried out by inductively coupled plasma optical emission spectrometry. The kinetics of Fe(III) biosorption was investigated at different initial concentrations of metal ion. The highest uptake capacity was found to be 16 mg of Fe(III) per gram of adsorbent with a contact time of 24 hr and at initial metal ion concentration of 34 mg/L. The uptake capacity of Fe(III) ion varied from 83.2 to 46.7% across the range of initial metal ion concentrations. The equilibrium data were evaluated by Langmuir and Freundlich isotherms, and were found to fit better with the latter (R2 = 0.9999). The surface morphology of the biomass and percentage of metal was characterized by using a scanning electron microscope equipped with energy dispersive X-ray spectroscopy. The functional groups on the cell wall surface of biomass involved in biosorption of heavy metals were studied by Fourier transform infrared spectroscopy spectrum.

APA, Harvard, Vancouver, ISO, and other styles

20

Moon, Ju, Célestine Belloeil, Madeline Ianna, and Ryoung Shin. "Arabidopsis CNGC Family Members Contribute to Heavy Metal Ion Uptake in Plants." International Journal of Molecular Sciences 20, no. 2 (2019): 413. http://dx.doi.org/10.3390/ijms20020413.

Full text

Abstract:

Heavy metal ions, including toxic concentrations of essential ions, negatively affect diverse metabolic and cellular processes. Heavy metal ions are known to enter cells in a non-selective manner; however, few studies have examined the regulation of heavy metal ion transport. Plant cyclic nucleotide-gated channels (CNGCs), a type of Ca2+-permeable-channel, have been suggested to be involved in the uptake of both essential and toxic cations. To determine the candidates responsible for heavy metal ion transport, a series of Arabidopsis CNGC mutants were examined for their response to Pb2+ and Cd2+ ions. The primary focus was on root growth and the analysis of the concentration of heavy metals in plants. Results, based on the analysis of primary root length, indicated that AtCNGC1, AtCNGC10, AtCNGC13 and AtCNGC19 play roles in Pb2+ toxicity, while AtCNGC11, AtCNGC13, AtCNGC16 and AtCNGC20 function in Cd2+ toxicity in Arabidopsis. Ion content analysis verified that the mutations of AtCNGC1 and AtCNGC13 resulted in reduced Pb2+ accumulation, while the mutations of AtCNGC11, AtCNGC15 and AtCNGC19 resulted in less Pb2+ and Cd2+ accumulation in plants. These findings provide functional evidence which support the roles of these AtCNGCs in the uptake and transport of Pb2+ or Cd2+ ion in plants.

APA, Harvard, Vancouver, ISO, and other styles

21

Qurbonova, Bagul Shuxrat qizi, and Dilshoda Baxtiyor qizi Abdug'afforova. "CHARACTERISTICS OF IRON EXCHANGE IN TUBERCULOSIS." Multidisciplinary Journal of Science and Technology 4, no. 11 (2024): 396–99. https://doi.org/10.5281/zenodo.14270112.

Full text

Abstract:

Mycobacterium tuberculosis requires iron for normal growth, but is subject to metal ion limitation due to its low solubility at biological pH and iron retention by mammalian hosts. The pathogen expresses a specific siderophore for Fe 3+ to chelate the metal ion from insoluble iron and the proteins transferrin, lactoferrin, and ferritin. Siderophore-mediated iron uptake is essential for survival in tuberculosis disease, as knockout mutants defective in siderophore synthesis or uptake failed to survive in iron-deficient environments and in host macrophages. However, since excess iron is toxic due to its catalytic role in the generation of free radicals, iron uptake must be regulated to maintain optimal intracellular iron levels. The main objective of this review is to provide a comprehensive overview of iron homeostasis in M. tuberculosis, discussed in the context of mycobactin biosynthesis, iron transport across the mycobacterial cell envelope, and storage of excess iron.

APA, Harvard, Vancouver, ISO, and other styles

22

Shin, Hyuksoo, Jihee Kim, Dowan Kim, et al. "Aqueous “polysulfide-ene” polymerization for sulfur-rich nanoparticles and their use in heavy metal ion remediation." Journal of Materials Chemistry A 6, no. 46 (2018): 23542–49. http://dx.doi.org/10.1039/c8ta05457f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Chua, Anita C. G., John K. Olynyk, Peter J. Leedman, and Debbie Trinder. "Nontransferrin-bound iron uptake by hepatocytes is increased in the Hfe knockout mouse model of hereditary hemochromatosis." Blood 104, no. 5 (2004): 1519–25. http://dx.doi.org/10.1182/blood-2003-11-3872.

Full text

Abstract:

Abstract Hereditary hemochromatosis (HH) is an iron-overload disorder caused by a C282Y mutation in the HFE gene. In HH, plasma nontransferrin-bound iron (NTBI) levels are increased and NTBI is bound mainly by citrate. The aim of this study was to examine the importance of NTBI in the pathogenesis of hepatic iron loading in Hfe knockout mice. Plasma NTBI levels were increased 2.5-fold in Hfe knockout mice compared with control mice. Total ferric citrate uptake by hepatocytes isolated from Hfe knockout mice (34.1 ± 2.8 pmol Fe/mg protein/min) increased by 2-fold compared with control mice (17.8 ± 2.7 pmol Fe/mg protein/min; P &lt; .001; mean ± SEM; n = 7). Ferrous ion chelators, bathophenanthroline disulfonate, and 2′,2-bipyridine inhibited ferric citrate uptake by hepatocytes from both mouse types. Divalent metal ions inhibited ferric citrate uptake by hepatocytes, as did diferric transferrin. Divalent metal transporter 1 (DMT1) mRNA and protein expression was increased approximately 2-fold by hepatocytes from Hfe knockout mice. We conclude that NTBI uptake by hepatocytes from Hfe knockout mice contributed to hepatic iron loading. Ferric ion was reduced to ferrous ion and taken up by hepatocytes by a pathway shared with diferric transferrin. Inhibition of uptake by divalent metals and up-regulation of DMT1 expression suggested that NTBI uptake was mediated by DMT1.

APA, Harvard, Vancouver, ISO, and other styles

24

Diefenbach, Ursula, Marcel Bloy, and Brigitte Stromburg. "Metal Ion Uptake of 2-(2-Pyridyl)Ethylamino-Substituted Phosphazenes." Phosphorus, Sulfur, and Silicon and the Related Elements 144, no. 1 (1999): 65–68. http://dx.doi.org/10.1080/10426509908546183.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Crist, Ray H., J. Robert Martin, and DeLanson R. Crist. "Ion-Exchange Aspects of Toxic Metal Uptake by Indian Mustard." International Journal of Phytoremediation 6, no. 1 (2004): 85–94. http://dx.doi.org/10.1080/16226510490440006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Amirnia, Shahram, Argyrios Margaritis, and Madhumita B. Ray. "Adsorption of Mixtures of Toxic Metal Ions Using Non-Viable Cells of Saccharomyces Cerevisiae." Adsorption Science & Technology 30, no. 1 (2012): 43–63. http://dx.doi.org/10.1260/0263-6174.30.1.43.

Full text

Abstract:

The use of waste biomaterial for the adsorption of heavy metal ions is an economically appealing alternative to conventional metal ion removal methods. In the present work, S. cerevisiae biomass has been shown to be capable of the simultaneous removal of more than 98% of Pb(II) ions, 60% of Zn(II) ions and up to 55% of Cu(II) ions from aqueous solutions in the 10–50 mg/ℓ concentration range. Model equations describing the removal efficiency of each metal ion were determined using Response Surface Methodology (RSM) with respect to operating conditions such as pH, initial metal ion concentration and biomass dosage. Characterization of the metal ion–biomass interactions responsible for biosorption was studied employing zeta potential measurements, BET, FT-IR and EDX techniques; these indicated that the uptake of metal ions by non-living yeast was a surface adsorption phenomenon. The results proved the involvement of an ion-exchange mechanism between the adsorbing metal ions and the cell walls. In the presence of the complete range of metal ions studied, yeast cells were more selective towards Pb(II) ions.

APA, Harvard, Vancouver, ISO, and other styles

27

Mustafa, S., A. Naeem, N. Rehana, and H. Y. Samad. "Cation-Exchange Properties of Aluminium(III) Phosphate." Adsorption Science & Technology 13, no. 4 (1996): 261–79. http://dx.doi.org/10.1177/026361749601300404.

Full text

Abstract:

Potentiometric titrations of aluminium(III) phosphate have been performed in the presence of aqueous electrolyte solutions containing Cu2+, Zn2+, Ni2+ and K+ ions as a function of the concentration of the latter, the pH and the temperature. The sorption of Zn2+ ions has also been studied and the data for metal ion sorption shown to correlate with the Potentiometric titration data, indicating that the process responsible for metal ion uptake is ion exchange. The pKa value of the exchanger and its thermodynamic parameters have been evaluated.

APA, Harvard, Vancouver, ISO, and other styles

28

Al-Qunaibit, M. H. "Divalent Cu, Cd, and Pb Biosorption in Mixed Solvents." Bioinorganic Chemistry and Applications 2009 (2009): 1–5. http://dx.doi.org/10.1155/2009/561091.

Full text

Abstract:

Dead driedChlorella vulgariswas studied in terms of its performance in binding divalent copper, cadmium, and lead ions from their aqueous or 50% v/v methanol, ethanol, and acetone solutions. The percentage uptake of cadmium ions exhibited a general decrease with decrease in dielectric constant values, while that of copper and lead ions showed a general decrease with increase in donor numbers. Uptake percentage becomes less sensitive to solvent properties the larger the atomic radius of the biosorbed ion, and uptake of copper was the most affected. FT-IR analyses revealed stability of the biomass in mixed solvents and a shift in vibrations of amide(I) and (II), carboxylate, glucose ring, and metal oxygen upon metal binding in all media.ΔνCOOvalues (59–69 cm−1) confirmed bidentate metal coordination to carboxylate ligands. The value ofνasCOOincreased slightly upon Cu, Cd, and Pb biosorption from aqueous solutions indicating lowering of symmetry, while a general decrease was noticed in mixed solvents pointing to the opposite. M–O stretching frequencies increased unexpectedly with increase in atomic mass as a result of solvent effect on the nature of binding sites. Lowering polarity of the solvent permits variations in metal-alga bonds strengths; the smaller the metal ion, the more affected.

APA, Harvard, Vancouver, ISO, and other styles

29

Lestari, Intan. "Biosorption of Zn (II) Metal Ion by Ca-Alginate Immobilized Durian (Durio Zibethinus) Seed." Journal of Chemical Natural Resources 1, no. 2 (2019): 60–68. http://dx.doi.org/10.32734/jcnar.v1i2.1254.

Full text

Abstract:

Heavy metal biosorption by alginate immobilized durian seed has been done. The immobilization of durian seed powder to Ca-alginate was able to improve biomass adsorption process, increase uptake capacity, ease separation from solution, generate and repeat biosorbent. In this experiment the effect of pH, contact time, concentration and temperature on the uptake capacity of metal ions Zn(II) in solution were studied. Biosorption was done batch methods and result was studied Langmuir and Freundlich adsorption isotherm. The adsorption of heavy metal was optimum in pH 5 with 75 mins contact time and Zn(II) ion under the concentration of 250-300 mg/l. The adsorption isotherm data was characterized using Langmuir and Freundlich equation. The equilibrium biosorption isotherm showed that alginate immobilized durian seed process has high affinities with adsorption capacities of 25.05 mg/g. All results showed that alginate immobilized durian seed is an alternative low cost biosorbent for heavy metal ion removal from aqueous solution

APA, Harvard, Vancouver, ISO, and other styles

30

Kuyucak, Nural, and Bohumil Volesky. "A Method of Metal Removal." Water Quality Research Journal 23, no. 3 (1988): 424–33. http://dx.doi.org/10.2166/wqrj.1988.031.

Full text

Abstract:

Abstract Selected non-living, inactivated materials of biological origin, such as algae, fungi, bacteria and their products, have been screened for their metal uptake capacity from solutions. Each biomass type exhibited different performance for metal species tested. The biosorbent performance also varied broadly with pH of the solution used. The biomass of a green alga Halimeda opuntia and a brown alga Sargassum natans have been identified for their extreme potential to concentrate chromium and gold, respectively. The optimum pH was 4-6 for chromium uptake and below 3 for gold uptake. A brown marine alga Ascophyllum nodosum sequestered cobalt well at pH 4.5 outperforming activated carbon and ion exchange resins. The optimum pH for silver uptake by biomass of a red alga Chondris crispus and for arsenic uptake by yeast Saccharomyces cerevisiae covered a broad range of pH 2-6 and pH 4-9, respectively. A red marine alga Palmaria palmata was the most functional biomass in sequestering platinum at pH below 3. The biosorptive uptake of chromium and gold was rather specific. It was not affected by the presence of other cations such as Cu2+, UO22+, Ca2+, Ni2+ or anions such as CO32−. Kinetics of the metal uptake, except for gold, was generally very rapid. Sequestered metals could be eluted from the biomass and the biosorbent material can subsequently be reused many times over. The work demonstrates existing potential of a new group of biosorbent materials of microbial origin which can be effectively applied in a novel process of metal recovery from dilute solutions. The process of biosorption has a commercial potential as documented by several new enterprises currently aggressively entering the field.

APA, Harvard, Vancouver, ISO, and other styles

31

Sánchez-Marín, Paula, Claude Fortin, and Peter G. C. Campbell. "Copper and lead internalisation by freshwater microalgae at different carbonate concentrations." Environmental Chemistry 10, no. 2 (2013): 80. http://dx.doi.org/10.1071/en13011.

Full text

Abstract:

Environmental context Metal–carbonato complexes have been reported to contribute to metal uptake and toxicity in aquatic organisms. We show that in the presence of lead–carbonato complexes, Pb internalisation by the microalga Chlamydomonas reinhardtii is higher than that predicted on the basis of the free Pb2+ concentration. This effect, which was not observed for another microalga that takes up Pb more slowly, is attributed to the very high rates of Pb uptake by C. reinhardtii, which result in diffusion limitation. Abstract The possible contribution of metal–carbonato complexes to metal uptake or toxicity has been mentioned several times in the literature, often in studies where dissolved inorganic carbon (DIC) concentrations and pH were varied together, but a thorough study of the effect on DIC on metal bioavailability to aquatic organisms has not been done. By using closed systems – allowing changes in DIC concentrations at fixed pH – and ion selective electrodes to determine free metal ion concentrations, we show that lead internalisation by the unicellular alga Chlamydomonas reinhardtii in the presence of high DIC concentrations is higher than predicted by the free Pb2+ ion concentration at bulk [Pb2+] lower than 50nM, but not at higher [Pb2+]. This effect is not observed for another microalga, Chlorella vulgaris, which shows a lower rate of Pb internalisation. Copper internalisation by C. reinhardtii seems also to be slightly higher than predicted on the basis of free Cu2+ at low (20nM) bulk Cu2+ concentrations but not at higher ones. The possibility that Pb (and Cu) internalisation by C. reinhardtii is partially limited by diffusion from the bulk solution to the algal surface is identified and discussed as a possible explanation for these results.

APA, Harvard, Vancouver, ISO, and other styles

32

Grba, Nenad, Cyrill Grengg, Mirjana Petronijević, Martin Dietzel, and Andre Baldermann. "Substantial Copper (Cu2+) Uptake by Metakaolin-Based Geopolymer and Its Resistance to Acid Leaching and Ion Exchange." Polymers 15, no. 8 (2023): 1971. http://dx.doi.org/10.3390/polym15081971.

Full text

Abstract:

Geopolymers are inorganic, chemically resistant aluminosilicate-based binding agents, which remove hazardous metal ions from exposed aqueous media. However, the removal efficiency of a given metal ion and the potential ion remobilization have to be assessed for individual geopolymers. Therefore, copper ions (Cu2+) were removed by a granulated, metakaolin-based geopolymer (GP) in water matrices. Subsequent ion exchange and leaching tests were used to determine the mineralogical and chemical properties as well as the resistance of the Cu2+-bearing GPs to corrosive aquatic environments. Experimental results indicate the pH of the reacted solutions to have a significant impact on the Cu2+ uptake systematics: the removal efficiency ranged from 34–91% at pH 4.1–5.7 up to ~100% at pH 11.1–12.4. This is equivalent to Cu2+ uptake capacities of up to 193 mg/g and 560 mg/g in acidic versus alkaline media. The uptake mechanism was governed by Cu2+-substitution for alkalis in exchangeable GP sites and by co-precipitation of gerhardtite (Cu2(NO3)(OH)3) or tenorite (CuO) and spertiniite (Cu(OH)2). All Cu-GPs showed excellent resistance to ion exchange (Cu2+ release: 0–2.4%) and acid leaching (Cu2+ release: 0.2–0.7%), suggesting that tailored GPs have a high potential to immobilize Cu2+ ions from aquatic media.

APA, Harvard, Vancouver, ISO, and other styles

33

Patel, Jayesh R., Dipan H. Sutaria, and Magan N. Patel. "Poly[1,3(2-ethoxy-4-hydroxy-5-propylphenylene)propylene] copolymer as an ion exchanger." High Performance Polymers 6, no. 3 (1994): 201–8. http://dx.doi.org/10.1088/0954-0083/6/3/003.

Full text

Abstract:

The present paper reports the synthesis and characterization of a copolymer, The copolymer sample was synthesized by Friedel-Crafts polycondensation of 2-hydroxy-4 ethoxypropiophenone with 1,3-propane diol in the presence of polyphosphoric acid catalyst. The copolymer was characterized by elemental analysis, IR spectroscopy and viscosity study, and its number-average molecular weight (M) was determined by non-aqueous titration and found to be 2855 g mol- 1. Chelation ion-exchange properties have also been studied, employing a batch-equilibration method. It was employed to study selectivity of metal ion uptake over a wide pH range and in media of various ionic strengths. The overall rate of metal uptake follows the order UOl + > Fe3 + > Cu2 + > Ni2 +.

APA, Harvard, Vancouver, ISO, and other styles

34

Gopkar, Dr. N. S. "Effect of pH on equilibrium Al (III) sorption capacity Pistia stratiotes Linn.." International Journal of Advance and Applied Research 11, no. 1 (2023): 474–77. https://doi.org/10.5281/zenodo.14880954.

Full text

Abstract:

Abstract: In the present study, metal ion uptake seems to be optimum at pH value of 5.0 and pH 6.0 in case the aquatic macrophyte Pistia stratiotes . The biosorption of metal ions was reduced when pH value was reduced from 5.0 to 1.0 and 6.0 to 1.0 respectively. There seems to the improvement in metal metal sorption with higher pH might be due to the increase in the amount of ligands for metal ion binding. Due to low pH, competition occurs between protons and metal ions, results in to less metal uptake as  low pH generates higher concentration of H+ ions. Hence metal ions must compete with H+ ions for attachment to the surface of functional groups of the biomass (Zouboulis et al. 1999). With the rise in pH, fewer H+ ions exist, and consequently, metal ions have a better chance to bind to the free binding sites. with the declining pH (˂6.0) and (˂5.0) decrease in biosorption of all the metal ions was observed respectively. Whereas, with the increase in pH above (>6.0) and (>5.0), decrease of biosorption was observed among all the metal ions studied, respectively. The optimum biosorption by Pistia stratiotes Linn. was recorded at a pH value of 5.0 (16.1 mg/g)  and the time required to occur maximum biosorption was recorded as 120 min.

APA, Harvard, Vancouver, ISO, and other styles

35

Skuza, Lidia, Izabela Szućko-Kociuba, Ewa Filip, and Izabela Bożek. "Natural Molecular Mechanisms of Plant Hyperaccumulation and Hypertolerance towards Heavy Metals." International Journal of Molecular Sciences 23, no. 16 (2022): 9335. http://dx.doi.org/10.3390/ijms23169335.

Full text

Abstract:

The main mechanism of plant tolerance is the avoidance of metal uptake, whereas the main mechanism of hyperaccumulation is the uptake and neutralization of metals through specific plant processes. These include the formation of symbioses with rhizosphere microorganisms, the secretion of substances into the soil and metal immobilization, cell wall modification, changes in the expression of genes encoding heavy metal transporters, heavy metal ion chelation, and sequestration, and regenerative heat-shock protein production. The aim of this work was to review the natural plant mechanisms that contribute towards increased heavy metal accumulation and tolerance, as well as a review of the hyperaccumulator phytoremediation capacity. Phytoremediation is a strategy for purifying heavy-metal-contaminated soils using higher plants species as hyperaccumulators.

APA, Harvard, Vancouver, ISO, and other styles

36

P., Chowdhury, Mukherjee A., and Singha B. "Synthesis of cross-linked graft copolymer hydrogel from maleic acid, poly(vinyl alcohol) and methylene bisacrylamide, and studies on its efficiency in uptaking zinc ion from aqueous solution." Journal of Indian Chemical Society Vol. 88, Oct 2011 (2011): 1517–24. https://doi.org/10.5281/zenodo.5790609.

Full text

Abstract:

Department of Chemistry, Visva-Bharati, Santiniketan-731 235, West Bengal, India E-mail : pranesh_02@yahoo.co.in Manuscript received 23 November 2010, accepted 25 February 2011 A novel graft copolymer hydrogel from maleic acid and poly(vinyl alcohol) has been synthesized and it is cross-linked by methylene bisacrylamide for the investigation of Its efficiency In uptaking zinc ion from aqueous solution. The swelling behavior, temperature sensitivity, gel content and swelling rate of the hydrogel were investigated. Metal ion uptake capacity of the polymer was evaluated In the light of changing pH, temperature, time and concentration. The polymer was characterized by chemical, thermal (TGA) and spectral (FTIR) data analysis. Surface morphology was Inspected with the help of SEM photograph. A plausible mechanism for zinc ion exchange has been suggested. The selectivity of the polymer towards metal ion has been investigated. Zinc ion has been isolated quantitatively from various synthetic mixture containing metal ions (Ni2, Cd2+, Cu2+), commonly found in the effluent of galvanization industry.

APA, Harvard, Vancouver, ISO, and other styles

37

Narayan Chandan Das and Wasudeo B. Gurnule. "Removal of Heavy Metal Ions from Water Using Chelating Copolymer Resin-IV Derived from 2-Hydroxy, 4-Methoxybenzophenone, 1, 5-Diaminonaphthalene and Formaldehyde." International Journal of Science and Research Archive 12, no. 1 (2024): 3058–65. http://dx.doi.org/10.30574/ijsra.2024.12.1.1196.

Full text

Abstract:

The resin 2-H, 4-MBP-1,5-DANF-IV was synthesized by the condensation of 2-hydroxy, 4-methoxybenzophenone and1, 5-diaminonaphthalene with formaldehyde in the presence of hydrochloric acid as a catalyst. The resin was characterized by elemental analysis, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and UV-Visible spectral studies. The chelation ion-exchange properties was studied for Ni2+, Cu2+, Co2+, Zn2+ and Pb2+ ions employing a batch equilibrium method. It was used to study of the selectivity of metal-ion uptake involving the measurements of the distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strength.The resin depicted a higher selectivity for Cu2+ and Ni2+ ion than for Co2+, Zn2+ and Pb2+ ions.

APA, Harvard, Vancouver, ISO, and other styles

38

Zhao, Chun-Mei, Peter G. C. Campbell, and Kevin J. Wilkinson. "When are metal complexes bioavailable?" Environmental Chemistry 13, no. 3 (2016): 425. http://dx.doi.org/10.1071/en15205.

Full text

Abstract:

Environmental contextThe concentration of a free metal cation has proved to be a useful predictor of metal bioaccumulation and toxicity, as represented by the free ion activity and biotic ligand models. However, under certain circumstances, metal complexes have been shown to contribute to metal bioavailability. In the current mini-review, we summarise the studies where the classic models fail and organise them into categories based on the different uptake pathways and kinetic processes. Our goal is to define the limits within which currently used models such as the biotic ligand model (BLM) can be applied with confidence, and to identify how these models might be expanded. AbstractNumerous data from studies over the past 30 years have shown that metal uptake and toxicity are often best predicted by the concentrations of free metal cations, which has led to the development of the largely successful free-ion activity model (FIAM) and biotic ligand model (BLM). Nonetheless, some exceptions to these classical models, showing enhanced metal bioavailability in the presence of metal complexes, have also been documented, although it is not yet fully understood to what extent these exceptions can or should be generalised. Only a few studies have specifically measured the bioaccumulation or toxicity of metal complexes while carefully measuring or controlling metal speciation. Fewer still have verified the fundamental assumptions of the classical models, especially when dealing with metal complexes. In the current paper, we have summarised the exceptions to classical models and categorised them into five groups based on the fundamental uptake pathways and kinetic processes. Our aim is to summarise the mechanisms involved in the interaction of metal complexes with organisms and to improve the predictive capability of the classic models when dealing with complexes.

APA, Harvard, Vancouver, ISO, and other styles

39

Nabi, S. A., A. Islam, and N. Rahman. "Synthesis, Characterization and Application of a Derivatized Acidic Salt of a Tetravalent Metal. Pyridine Anchored on to Tin(IV) Tungstoselenate." Adsorption Science & Technology 18, no. 6 (2000): 551–60. http://dx.doi.org/10.1260/0263617001493611.

Full text

Abstract:

The inorgano-organic ion-exchanger, tin(IV) tungstoselenate–pyridine, has been prepared by derivatizing the inorganic ion-exchange material, tin(IV) tungstoselenate, with an organic moiety, pyridine. Chemical studies showed the tin(IV) tungstoselenate/pyridine mole ratio to be 806.5:1, indicating a weak sorption of pyridine on to the surface of the tin(IV) tungstoselenate. The material was characterized on the basis of SEM, FT-IR, TGA and DTA studies. The uptake of Cu2+, Ni2+, Fe2+ and Fe3+ ions was found to be much higher on tin(IV) tungstoselenate–pyridine relative to tin(IV) tungstoselenate. The uptake of these metal ions as a function of loading and pH was also studied when the following affinity order was observed: Cu2+ > Co2+ > Ni2+ > Fe2+ > Fe3+. The uptake of metal ions increased initially with loading but became constant at higher loading. The most favourable pH range was found to be that between 3.5 and 4.5.

APA, Harvard, Vancouver, ISO, and other styles

40

Yeo, Hyun Ku, Jina Kang, Young Woo Park, Jung-Suk Sung, and Jae Young Lee. "Crystallization and preliminary X-ray diffraction analysis of the metalloregulatory protein DtxR fromThermoplasma acidophilum." Acta Crystallographica Section F Structural Biology and Crystallization Communications 68, no. 2 (2012): 172–74. http://dx.doi.org/10.1107/s1744309111051700.

Full text

Abstract:

The diphtheria toxin repressor (DtxR) is a metal-ion-dependent transcriptional regulator which regulates genes encoding proteins involved in metal-ion uptake to maintain metal-ion homeostasis. DtxR fromThermoplasma acidophilumwas cloned and overexpressed inEscherichia coli. Crystals of N-terminally His-tagged DtxR were obtained by hanging-drop vapour diffusion and diffracted to 1.8 Å resolution. DtxR was crystallized at 296 K using polyethylene glycol 4000 as a precipitant. The crystals belonged to the orthorhombic space groupP21212, with unit-cell parametersa= 61.14,b= 84.61,c= 46.91 Å, α = β = γ = 90°. The asymmetric unit contained approximately one monomer of DtxR, giving a crystal volume per mass (VM) of 2.22 Å3 Da−1and a solvent content of 44.6%.

APA, Harvard, Vancouver, ISO, and other styles

41

Giron, Ofelia D., Rio Carlo M. Lirag, Susan D. Arco, and Leni L. Quirit. "Modification of Silica Gel with 1,10-Phenanthroline for Cd(II) and Pb(II) Adsorption." KIMIKA 24, no. 1 (2013): 18–24. http://dx.doi.org/10.26534/kimika.v24i1.18-24.

Full text

Abstract:

Silica gel was modified via silylation using 3-chloropropyltrimethylsilane and functionalization using 1,10-phenanthroline. FTIR, DSC and quantitative SEM-EDX data were obtained to confirm functionalization. The uptakes of cadmium (II) and lead (II) by the phenanthroline-modified silica (Phen-Si) were determined using equilibrium and dynamic methods. For the equilibrium method, percent adsorbed for 5 to 200 ppm metal ion solutions ranged from 0 % to 93.2 % (for Cd) and from 81.6 % to 95.2 % (for Pb) The maximum uptake of Phen-Si is 91.89 mg Pb/g silica and 93.06 mg Cd/g silica for the equilibrium method while for the dynamic method, maximum uptake was 25.65 ± 6.52 mg Pb/g silica and 17.68 ± 2.33 mg Cd/g silica.

APA, Harvard, Vancouver, ISO, and other styles

42

Micic, Maja, Simonida Tomic, Jovanka Filipovic, and Edin Suljovrujic. "Silver(I)-complexes with an itaconic acid-based hydrogel." Chemical Industry 63, no. 3 (2009): 137–42. http://dx.doi.org/10.2298/hemind0903137m.

Full text

Abstract:

Silver(I) itaconic acid-based hydrogel complexes were synthesized and characterized in order to examine the potential use of these systems; FTIR, AFM, in vitro fluid-uptake, metal sorption and antibacterial activity assay measurements were used for the characterization. Metal (silver(I)) ion uptaken by IA-based hydrogels was determined by inductively coupled plasma mass spectrometry. The coordination sites for metal ions were identified and the stability in in vitro condition was determined. Incorporation of silver(I) ions into hydrogels and the influence of these ions on the diffusion properties of hydrogels were analyzed and discussed, too; it was found that the itaconic acid moiety in hydrogels is the determining factor which influences metal ion binding and therefore fluid uptake inside the polymeric network. Furthermore, silver(I) itaconic acid-based hydrogel showed a satisfactory antibacterial activity. The most advanced feature of these materials is that the silver ions embedded throughout the networks leaches out via controlled manner with time in aqueous media. Therefore, the ions escape from the swollen networks with time and interact with the bacteria. Because of a good dispersion of silver ions in Ag(I)-P(HEMA/2IA) hydrogel complex, we have evaluated the antibacterial activity for this sample. As expected, the number of colonies grown surrounding the Ag(I)- -P(HEMA/2IA) hydrogel complex was found to be almost nil, whereas the pure P(HEMA/2IA) hydrogel did not show any effect on Escherichia coli. Therefore, we conclude that the Ag(I)-P(HEMA/IA) hydrogel complexes are excellent antibacterial materials. Due to these facts, the silver ion IA- -based hydrogel complexes reported here might be used as smart materials in the range of biomedical applications, including drug-delivery devices, biosensors, wound healing dressings, tissue reconstruction and organ repair.

APA, Harvard, Vancouver, ISO, and other styles

43

Shanmugavalli, R., P. S. Syed Shabudeen, R. Venckatesh, K. Kadirvelu, S. Madhavakrishnan, and S. Pattabhi. "Uptake of Pb(II) ion From Aqueous Solution Using Silk Cotton Hull Carbon: An Agricultural Waste Biomass." E-Journal of Chemistry 3, no. 4 (2006): 218–29. http://dx.doi.org/10.1155/2006/496309.

Full text

Abstract:

Activated carbon prepared from silk cotton hull (SCH) was used for the adsorptive removal of Pb(II) ion from aqueous solution. The raw material used for the preparation of activated carbon is the waste of agricultural product; the production of this carbon is expected to be economically feasible. Parameters such as agitation time, metal ion concentration, adsorbent dose,pH and Particle size were studied. Adsorption equilibrium was reached within 80 min for 10, 20, 30 and 40mg/l of Pb(II) ion with 50mg of carbon per mL of solution. Adsorption parameters were determined using both Langmuir and Freundlich isotherm models. The adsorption efficiency reached 100% for 20, 30 and 40mg/l of Pb(II) ion with 120, 140 and 150mg of carbon. Pb(II) ion removal increased as thepH increased from 2 to 5 and remains constant up topH 10. Desorption studies were also carried out with dilute hydrochloric acid to know the mechanism of adsorption. Quantitative desorption of Pb(II) ion from carbon indicates that adsorption of metal ion is by ion-exchange. Efficiency of the adsorption of SCH was also studied with Pb containing industrial wastewater by varyingpH and carbon concentration.

APA, Harvard, Vancouver, ISO, and other styles

44

Trublet, Mylène, Daniela Rusanova, and Oleg N. Antzutkin. "Revisiting syntheses of Ti(iv)/H2PO4–HPO4 functional ion-exchangers, properties and features." New Journal of Chemistry 42, no. 2 (2018): 838–45. http://dx.doi.org/10.1039/c7nj03065g.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

GOLUI, D., S. P. DATTA, B. S. DWIVEDI, and M. C. MEENA. "Comparison of simple soil-solution extraction techniques for assessing transfer of metals from soil to plant in contaminated soils." Indian Journal of Agricultural Sciences 88, no. 6 (2018): 964–69. http://dx.doi.org/10.56093/ijas.v88i6.80655.

Full text

Abstract:

An attempt was made to evaluate simple techniques for extraction of soil solution for predicting uptake of Zn, Cu, Ni, Pb and Cd by spinach (Beta vulgaris L. var. All Green) grown on metal contaminated soils under modelling framework. Twenty-eight surface soil samples (0-15 cm) with heterogeneous chemical properties were collected. A pot experiment was conducted using spinach as a test crop. The leachate from experimental pots was collected with the help of plastic container installed below the pots. The 1:2 and 1:5 soil: water ratio was used for soil solutionextraction. The total concentration of Zn, Cu, Ni, Pb, and Cd in soil solution was determined using ICP-MS. Harvested plant sample was analyzed for total Zn, Cu, Ni, Pb, and Cd using ICP-MS. For predicting metal uptake by spinach free ion activity model (FIAM) was used and total metal concentration in soil solution was used as an input of FIAM. Higher concentration of all metal in 1:5 soil-water ratio were recorded than that in 1:2 soil-water ratio. The free ion activity model as a function of total metal concentration in soil solution, as measured by 1:5 soil: water extraction, could explain the variability in metal content in spinach to the extent of 94% for Zn, 67% for Cu, 80% for Ni, 50% for Pb and 75% for Cd, respectively. Extraction of soil with 1:5 soil-water ratio is more efficient and suitable for predicting metal uptake by spinach as compared to that of 1:2 and leachate extraction.

APA, Harvard, Vancouver, ISO, and other styles

46

Guo, Chao, Jingjing Hu, Wenqiang Gao, et al. "Mechanosensation triggers enhanced heavy metal ion uptake by non-glandular trichomes." Journal of Hazardous Materials 426 (March 2022): 127983. http://dx.doi.org/10.1016/j.jhazmat.2021.127983.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Demirbaş, Ayhan. "Metal ion uptake by mushrooms from natural and artificially enriched soils." Food Chemistry 78, no. 1 (2002): 89–93. http://dx.doi.org/10.1016/s0308-8146(01)00389-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Reddy, A. Ravikumar, and K. Hussain Reddy. "Heavy metal ion uptake properties of polystyrene-supported chelating polymer resins." Journal of Chemical Sciences 115, no. 3 (2003): 155–60. http://dx.doi.org/10.1007/bf02704254.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Chaidir, Zulkarnain, Qomariah Hasanah, Qomariah Hasanah, Rahmiana Zein, and Rahmiana Zein. "PENYERAPAN ION LOGAM Cr(III) DAN Cr(VI) DALAM LARUTAN MENGGUNAKAN KULIT BUAH JENGKOL (Pithecellobium jiringa (JACK) PRAIN.)." Jurnal Riset Kimia 8, no. 2 (2015): 189. http://dx.doi.org/10.25077/jrk.v8i2.239.

Full text

Abstract:

Jengkol shells (Pithecellobium jiringa) an agricultural waste from typical Indonesian plant has been investigated for its ability to absorb heavy metal ions Cr VI and Cr III . Effect of pH, concentration, contact time, mass and the speed of stirring biosorben studied by extraction method. Concentration of metal ions Cr VI and Cr III was measured using Atomic Absorption Spectrophotometer (AAS). The optimum conditions for metal ion uptake of Cr VI occurs at pH 4, the concentration of 7000 mg/L, contact time of 60 minutes, 0.1 g biosorben mass and stirring speed 100 rpm. For the metal ions Cr III wa obtained conditions optimum at pH 5, the concentration of 1500 mg/L, contact time of 60 minutes, 0.1 g biosorben mass and stirring speed 100 rpm. Functional groups contained in the jengkol shells analyzed by Fourier Transform Infra Red (FTIR). Data equilibrium uptake of metal ions Cr VI and Cr III by the jengkol shells analyzed using two isotherm models , namely Langmuir and Freundlich isotherm models . The absorption of both the metal ions tend to follow the Langmuir isotherm models in which the absorption capacity of metal ions obtained for Cr VI ) and Cr III is 24.9376 mg / g and 39. 0625 mg /g . The optimum condition was applied to study the river Batang Arau at Padang city obtained a capacity of 15.065 mg/ g with 45 efficiency, 94 % for the uptake of metal ions Cr (total).

APA, Harvard, Vancouver, ISO, and other styles

50

Wang, Wen-An, Andrea Garofoli, Evandro Ferrada, et al. "Human genetic variants in SLC39A8 impact uptake and steady-state metal levels within the cell." Life Science Alliance 8, no. 4 (2025): e202403028. https://doi.org/10.26508/lsa.202403028.

Full text

Abstract:

The humanSLC39A8(hSLC39A8) gene encodes a plasma membrane protein SLC39A8 (ZIP8) that mediates the specific uptake of the metals Cd2+, Mn2+, Zn2+, Fe2+, Co2+, and Se4+. Pathogenic variants withinhSLC39A8are associated with congenital disorder of glycosylation type 2 (CDG type II) or Leigh-like syndrome. However, numerous mutations of uncertain significance are also linked to different conditions or benign traits. Our study characterized 21hSLC39A8variants and measured their impact on protein localization and intracellular levels of Cd2+, Zn2+, and Mn2+. We identified four variants that disrupt protein expression, five variants with high retention in the endoplasmic reticulum, and 12 variants with localization to the plasma membrane. From the 12 variants with plasma membrane localization, we identified three with complete loss of detectable ion uptake by the cell and five with differential uptake between metal ions. Further in silico analysis on protein stability identified variants that may affect the stability of homodimer interfaces. This study elucidates the variety of effects ofhSLC39A8variants on ZIP8 and on diseases involving disrupted metal ion homeostasis.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Metal ion uptake'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles