In vivo kinetic release of five metal ions (iron, titanium, nickel, copper, and chromium) from fixed orthodontic alloys in Erbil city-Kurdistan region/Iraq

2021 ◽  
Author(s):  
Shireen Ibrahim Hamadamin
Keyword(s):  
Metal Ions ◽  
Kurdistan Region ◽  
Nickel Copper ◽  
Titanium Nickel ◽  
Kinetic Release

scholarly journals Crystallographic and X-ray absorption spectroscopic characterization of Helicobacter pylori UreE bound to Ni2+ and Zn2+ reveals a role for the disordered C-terminal arm in metal trafficking

2012 ◽  
Vol 441 (3) ◽  
pp. 1017-1035 ◽  
Author(s):  
Katarzyna Banaszak ◽  
Vlad Martin-Diaconescu ◽  
Matteo Bellucci ◽  
Barbara Zambelli ◽  
Wojciech Rypniewski ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Metal Ions ◽  
Metal Binding ◽  
Metal Ion ◽  
Mutual Influence ◽  
Accurate Information ◽  
Metal Ion Binding ◽  
X Ray ◽  
X Ray Absorption

The survival and growth of the pathogen Helicobacter pylori in the gastric acidic environment is ensured by the activity of urease, an enzyme containing two essential Ni2+ ions in the active site. The metallo-chaperone UreE facilitates in vivo Ni2+ insertion into the apoenzyme. Crystals of apo-HpUreE (H. pylori UreE) and its Ni2+- and Zn2+-bound forms were obtained from protein solutions in the absence and presence of the metal ions. The crystal structures of the homodimeric protein, determined at 2.00 Å (apo), 1.59 Å (Ni2+) and 2.52 Å (Zn2+) resolution, show the conserved proximal and solvent-exposed His102 residues from two adjacent monomers invariably involved in metal binding. The C-terminal regions of the apoprotein are disordered in the crystal, but acquire significant ordering in the presence of the metal ions due to the binding of His152. The analysis of X-ray absorption spectral data obtained using solutions of Ni2+- and Zn2+-bound HpUreE provided accurate information of the metal-ion environment in the absence of solid-state effects. These results reveal the role of the histidine residues at the protein C-terminus in metal-ion binding, and the mutual influence of protein framework and metal-ion stereo-electronic properties in establishing co-ordination number and geometry leading to metal selectivity.

scholarly journals An improved assay for bacterial methane mono-oxygenase: some properties of the enzyme from Methylomonas methanica

1975 ◽  
Vol 151 (2) ◽  
pp. 459-462 ◽  
Author(s):  
J Colby ◽  
H Dalton ◽  
R Whittenbury
Keyword(s):  
Metal Ions ◽  
Methane Oxidation ◽  
Metal Binding ◽  
Methylomonas Methanica

Extracts of Methylomonas methanica catalyse the O2-and NAD(P)H-dependent disappearance of bromomethane. The activity is unstable at 2 degrees C but is stable at --70 degrees C for several weeks. Bromomethane mono-oxygenase is particulate and is inhibited by metal-binding reagents, by compounds SKF 525A and Lilly 53325, by some metal ions and by acetylene. Evidence is presented that indicates that bromomethane mono-oxygenase is the enzyme responsible for methane oxidation in vivo.

scholarly journals Peptide-tags for site-specific protein labelling in vitro and in vivo

2016 ◽  
Vol 12 (6) ◽  
pp. 1731-1745 ◽  
Author(s):  
Jonathan Lotze ◽  
Ulrike Reinhardt ◽  
Oliver Seitz ◽  
Annette G. Beck-Sickinger
Keyword(s):  
Metal Ions ◽  
Small Molecules ◽  
Protein Localization ◽  
Specific Protein ◽  
Site Specific ◽  
Protein Labelling ◽  
Peptide Interactions ◽  
Peptide Tags

Peptide-tag based labelling can be achieved by (i) enzymes (ii) recognition of metal ions or small molecules and (iii) peptide–peptide interactions and enables site-specific protein visualization to investigate protein localization and trafficking.

scholarly journals Effect of metal ions on the in vitro availability of enoxacin, its in vivo implications, kinetic and antibacterial studies

Química Nova ◽  
2011 ◽  
Vol 34 (2) ◽  
pp. 186-189 ◽  
Author(s):  
Najma Sultana ◽  
Erum Humza ◽  
Muhammad Saeed Arayne ◽  
Urooj Haroon
Keyword(s):  
Metal Ions ◽  
Antibacterial Studies ◽  
In Vitro Availability

Proton-induced X-ray production in titanium, nickel, copper, molybdenum and silver

1976 ◽  
Vol 9 (3) ◽  
pp. 455-460 ◽  
Author(s):  
Md Rashiduzzaman Khan ◽  
D Crumpton ◽  
P E Francois
Keyword(s):  
X Ray ◽  
Nickel Copper ◽  
Titanium Nickel

Binuclear metal chelate complexes of anthraquinones having a MO4 chromophore. Part 1. Quinizarin

1987 ◽  
Vol 65 (7) ◽  
pp. 1485-1490 ◽  
Author(s):  
M. N. Bakola-Christianopoulou ◽  
P. D. Akrivos ◽  
M. Baumgarten
Keyword(s):  
Metal Ions ◽  
Magnetic Measurements ◽  
Metal Chelate ◽  
Transition Elements ◽  
Chelate Complexes ◽  
Cobalt Nickel ◽  
Oxygen Donor ◽  
Nickel Copper ◽  
Square Planar ◽  
Coordination Spheres

Homobinuclear metal chelate complexes having 1,4-dihydroxy-9,10-anthracenedione (quinizarin) as a bridging unit have been prepared with four bivalent first row transition elements, namely cobalt, nickel, copper, and zinc. The coordination spheres of the metal ions consist of two nearly equivalent six-membered rings with oxygen donor atoms derived from the quinizarin and the terminal ligands which are either β-diketones or salicylic aldehyde. TG, spectroscopic (ir, uv–vis, epr), and magnetic measurements have been applied to an investigation of the geometry adopted by the MO4 chromophores. The results are consistent with varying degrees of distortion from the ideal square planar toward a tetrahedral arrangement around the metal ions, closely related to the specific metal center involved.

scholarly journals Characterization and comparison of PM<sub>2.5</sub> oxidative potential assessed by two acellular assays

2020 ◽  
Vol 20 (9) ◽  
pp. 5197-5210 ◽  
Author(s):  
Dong Gao ◽  
Krystal J. Godri Pollitt ◽  
James A. Mulholland ◽  
Armistead G. Russell ◽  
Rodney J. Weber
Keyword(s):  
Metal Ions ◽  
Water Soluble ◽  
Metal Species ◽  
Urban Site ◽  
Chemical Components ◽  
Linear Regression Models ◽  
Oxidative Potential ◽  
Metal Interactions ◽  
Metal Metal

Abstract. The capability of ambient particles to generate in vivo reactive oxygen species (ROS), called oxidative potential (OP), is a potential metric for evaluating the health effects of particulate matter (PM) and is supported by several recent epidemiological investigations. Studies using various types of OP assays differ in their sensitivities to varying PM chemical components. In this study, we systematically compared two health-relevant acellular OP assays that track the depletion of antioxidants or reductant surrogates: (i) the synthetic respiratory-tract lining fluid (RTLF) assay that tracks the depletion of ascorbic acid (AA) and glutathione (GSH) and (ii) the dithiothreitol (DTT) assay that tracks the depletion of DTT. Yearlong daily samples were collected at an urban site in Atlanta, GA (Jefferson Street), during 2017, and both DTT and RTLF assays were performed to measure the OP of water-soluble PM2.5 components. PM2.5 mass and major chemical components, including metals, ions, and organic and elemental carbon were also analyzed. Correlation analysis found that OP as measured by the DTT and AA depletion (OPDTT and OPAA, respectively) were correlated with both organics and some water-soluble metal species, whereas that from the GSH depletion (OPGSH) was exclusively sensitive to water-soluble Cu. These OP assays were moderately correlated with each other due to the common contribution from metal ions. OPDTT and OPAA were moderately correlated with PM2.5 mass with Pearson's r=0.55 and 0.56, respectively, whereas OPGSH exhibited a lower correlation (r=0.24). There was little seasonal variation in the OP levels for all assays due to the weak seasonality of OP-associated species. Multivariate linear regression models were developed to predict OP measures from the particle composition data. Variability in OPDTT and OPAA were not only attributed to the concentrations of metal ions (mainly Fe and Cu) and organic compounds but also to antagonistic metal–organic and metal–metal interactions. OPGSH was sensitive to the change in water-soluble Cu and brown carbon (BrC), a proxy for ambient humic-like substances.

scholarly journals Comparative inhibition by hard and soft metal ions of steroid-binding capacity of renal mineralocorticoid receptor cross-linked to the 90-kDa heat-shock protein heterocomplex

1999 ◽  
Vol 341 (3) ◽  
pp. 585-592 ◽  
Author(s):  
Mario D. GALIGNIANA ◽  
Graciela PIWIEN-PILIPUK
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Metal Ions ◽  
Mineralocorticoid Receptor ◽  
Binding Capacity ◽  
Toxic Effects ◽  
Chemical Hardness ◽  
Activation Process ◽  
Steroid Binding

We analysed the inhibitory effectsin vitro and in vivo of several metal ions on aldosterone binding to the rat kidney mineralocorticoid receptor with the purpose of assessing possible toxic effects of those ions on sodium retention, as well as to obtain information on receptor structural requirements for ligand binding. For the assaysin vitro, the inhibitory effects of 20 metal ions were analysed on steroid-binding capacity for renal receptor cross-linked to 90-kDa heat-shock protein (hsp90) by pretreatment with dimethyl pimelimidate. Cross-linking prevented the artifactual dissociation of hsp90 (and, consequently, the loss of steroid binding) from the mineralocorticoid receptor due to the presence of high concentrations of salt in the incubation medium. Cross-linked heterocomplex showed no difference in ligand specificity and affinity with respect to native receptor, but increased stability upon thermal- or ionic-strength-induced destabilization was observed. Treatments in vitro with metal ions in the range 10-8-10-1 M resulted in a differential inhibitory effect for each particular ion on aldosterone binding. Using the negative logarithm of metal concentration for 50% inhibition, the ions could be correlated with their Klopman hardness constants. The analysis of this relationship led us to postulate three types of reaction: with thiol, imidazole and carboxyl groups. The essential role played by these residues in steroid binding was confirmed by chemical modification of cysteines with dithionitrobenzoic acid, histidines with diethyl pyrocarbonate and acidic amino acids with Woodward's reagent (N-ethyl-5-phenylisoxazolium-3′-sulphonate). Importantly, the toxic effects of some metal ions were also observed by treatments in vivo of adrenalectomized rats on both steroid-binding capacity and aldosterone-dependent sodium-retaining properties. We suggest that those amino acid residues are involved in the activation process of the mineralocorticoid receptor upon steroid binding. Thus toxic effects observed with these metal ions may be a consequence of modifications of those essential groups. Our results support the notion that toxicity of metals on renal mineralocorticoid function may be predicted according to their chemical hardness.

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