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Chemosphere May 2021Heavy metals pose a serious threat if they go beyond permissible limits in our bodies. Much heavy metal's viz. Lead, Chromium, Arsenic, Mercury, Nickel, and Cadmium pose... (Review)
Review
Heavy metals pose a serious threat if they go beyond permissible limits in our bodies. Much heavy metal's viz. Lead, Chromium, Arsenic, Mercury, Nickel, and Cadmium pose a serious threat when they go beyond permissible limits and cause hepatotoxicity. They cause the generation of ROS which in turn causes numerous injuries and undesirable changes in the liver. Epidemiological studies have shown an increase in the levels of such heavy metals in the environment posing a serious threat to human health. Epigenetic alterations have been seen in the event of exposure to such heavy metals. Apoptosis, caspase activation as well as ultrastructural changes in the hepatocytes have also been seen due to heavy metals. Inflammation involving TNF-alpha, pro-inflammatory cytokines, MAPK, ERK pathways have been seen in the event of heavy metal hepatotoxicity. All these have shown that these heavy metals pose a serious threat to human health in particular and the environment as a whole.
Topics: Arsenic; Cadmium; Chemical and Drug Induced Liver Injury; Chromium; Humans; Lead; Mercury; Metals, Heavy; Nickel
PubMed: 33736223
DOI: 10.1016/j.chemosphere.2021.129735 -
Macromolecular Rapid Communications Jul 2017There is increasing evidence that stimuli-responsive nanomaterials have become significantly critical components of modern materials design and technological... (Review)
Review
There is increasing evidence that stimuli-responsive nanomaterials have become significantly critical components of modern materials design and technological developments. Recent advances in synthesis and fabrication of stimuli-responsive polymeric nanoparticles with built-in stimuli-responsive components (Part A) and surface modifications of functional nanoparticles that facilitate responsiveness (Part B) are outlined here. The synthesis and construction of stimuli-responsive spherical, core-shell, concentric, hollow, Janus, gibbous/inverse gibbous, and cocklebur morphologies are discussed in Part A, with the focus on shape, color, or size changes resulting from external stimuli. Although inorganic/metallic nanoparticles exhibit many useful properties, including thermal or electrical conductivity, catalytic activity, or magnetic properties, their assemblies and formation of higher order constructs are often enhanced by surface modifications. Section B focuses on selected surface reactions that lead to responsiveness achieved by decorating nanoparticles with stimuli-responsive polymers. Although grafting-to and grafting-from dominate these synthetic efforts, there are opportunities for developing novel synthetic approaches facilitating controllable recognition, signaling, or sequential responses. Many nanotechnologies utilize a combination of organic and inorganic phases to produce ceramic or metallic nanoparticles. One can envision the development of new properties by combining inorganic (metals, metal oxides) and organic (polymer) phases into one nanoparticle designated as "ceramers" (inorganics) and "metamers" (metallic).
Topics: Inorganic Chemicals; Metals; Nanoparticles; Nanostructures; Nanotechnology; Polymers
PubMed: 28497535
DOI: 10.1002/marc.201700030 -
Current Opinion in Chemical Biology Feb 2022Inorganic metals supplement the chemical repertoire of organic molecules, especially proteins. This requires the correct metals to associate with proteins at metalation.... (Review)
Review
Inorganic metals supplement the chemical repertoire of organic molecules, especially proteins. This requires the correct metals to associate with proteins at metalation. Protein mismetalation typically occurs when excesses of unbound metals compete for a binding site ex vivo. However, in biology, excesses of metal-binding sites typically compete for limiting amounts of exchangeable metals. Here, we summarise mechanisms of metal homeostasis that sustain optimal metal availabilities in biology. We describe recent progress to understand metalation by comparing the strength of metal binding to a protein versus the strength of binding to competing sites inside cells.
Topics: Biology; Cobalt; Copper; Manganese; Metals; Zinc
PubMed: 34763208
DOI: 10.1016/j.cbpa.2021.102095 -
Trends in Biotechnology Jan 2017Biotechnology could provide many innovative alternatives for changing the way metals are obtained. Microbes have been used to dissolve metallic minerals and release... (Review)
Review
Biotechnology could provide many innovative alternatives for changing the way metals are obtained. Microbes have been used to dissolve metallic minerals and release metal ions into solution, from which pure metal can be obtained by electrolysis. Plants that accumulate metals in their roots and leaves have been used to concentrate metals, and mineral-binding peptides might be used to separate minerals. However, for billions of years microbes have been interacting with metals. Microbial communities in and near mineral sources are therefore a rich source of genetic information which could be used to create synthetic or modified microbiomes that concentrate metals. This would be a complete paradigm-change with enormous scope for transforming the way metals are obtained.
Topics: Bacteria; Conservation of Natural Resources; Metals; Minerals; Mining; Soil Microbiology
PubMed: 27612568
DOI: 10.1016/j.tibtech.2016.07.004 -
Metal Ions in Life Sciences Apr 2017Heavy metal exposure has long been associated with metallothionein (MT) regulation and its functions. MT is a ubiquitous, cysteine-rich protein that is involved in... (Review)
Review
Heavy metal exposure has long been associated with metallothionein (MT) regulation and its functions. MT is a ubiquitous, cysteine-rich protein that is involved in homeostatic metal response for the essential metals zinc and copper, as well as detoxification of heavy metals; the most commonly proposed being cadmium. MT binds in vivo to a number of metals in addition to zinc, cadmium and copper, such as bismuth. In vitro, metallation with a wide range of metals (especially mercury, arsenic, and lead) has been reported using a variety of analytical methods. To fully understand MT and its role with lead metabolism, we will describe how MT interacts with a wide variety of metals that bind in vitro. In general, affinity to the metal-binding cysteine residues of MT follows that of metal binding to thiols: Zn(II) < Pb(II) < Cd (II) < Cu(I) < Ag(I) < Hg(II) < Bi(III). To introduce the metal binding properties that we feel directly relate to the metallation of metallothionein by Pb(II), we will explore MT's interactions with metals long known as toxic, particularly, Cd(II), Hg(II), and As(III), along with xenobiotic metals, and how these metal-binding studies complement those of lead binding. Lead's effects on an organism's physiological functions are not fully understood, but it is known that chronic exposure inflicts amongst other factors pernicious anemia and developmental issues in the brain, especially in children who are more vulnerable to its toxic effects. Understanding the interaction of lead with metallothioneins throughout the biosphere, from bacteria, to algae, to fish, to humans, is important in determining pathways for lead to enter and damage physiologically significant protein function, and thereby its toxicity.
Topics: Animals; Humans; Lead; Lead Poisoning; Metallothionein; Protein Binding
PubMed: 28731302
DOI: 10.1515/9783110434330-009 -
Current Opinion in Insect Science Jun 2022Manganese is an essential element for maintaining life. Overexposure to the metal, however, can be toxic to organisms. Given the significant function of manganese in... (Review)
Review
Manganese is an essential element for maintaining life. Overexposure to the metal, however, can be toxic to organisms. Given the significant function of manganese in insects, agriculture, and human disease, as well as in the healthy ecology of the planet, the biological activities of manganese in insects needs consideration. Because of the role of manganese as a cofactor for essential enzymes present in different organelles, both over and underexposure to manganese has a multifaceted effect on organisms. At the physiological level, the effects of insect exposure to the metal on enzymatic activities and consequent alteration of insect behaviors are best explained through the metal's role in modulating the dopaminergic system. Despite numerous examples that alterations in manganese homeostasis have profound effects on insects, the cellular mechanisms that ensure homeostasis of this essential metal remain presently unknown, calling for further research in this area.
Topics: Animals; Homeostasis; Insecta; Ions; Manganese; Metals
PubMed: 35278758
DOI: 10.1016/j.cois.2022.100886 -
FEBS Letters Jan 2023Metalation, the acquisition of metals by proteins, must avoid mis-metalation with tighter binding metals. This is illustrated by four selected proteins that require... (Review)
Review
Metalation, the acquisition of metals by proteins, must avoid mis-metalation with tighter binding metals. This is illustrated by four selected proteins that require different metals: all show similar ranked orders of affinity for bioavailable metals, as described in a universal affinity series (the Irving-Williams series). Crucially, cellular protein metalation occurs in competition with other metal binding sites. The strength of this competition defines the intracellular availability of each metal: its magnitude has been estimated by calibrating a cells' set of DNA-binding, metal-sensing, transcriptional regulators. This has established that metal availabilities (as free energies for forming metal complexes) are maintained to the inverse of the universal series. The tightest binding metals are least available. With these availabilities, correct metalation is achieved.
Topics: Metals; Metalloproteins; Bacterial Proteins; Cobalt; Copper
PubMed: 36124565
DOI: 10.1002/1873-3468.14500 -
The Biochemical Journal Mar 2021Metal ions play many critical roles in biology, as structural and catalytic cofactors, and as cell regulatory and signalling elements. The metal-protein affinity,... (Review)
Review
Metal ions play many critical roles in biology, as structural and catalytic cofactors, and as cell regulatory and signalling elements. The metal-protein affinity, expressed conveniently by the metal dissociation constant, KD, describes the thermodynamic strength of a metal-protein interaction and is a key parameter that can be used, for example, to understand how proteins may acquire metals in a cell and to identify dynamic elements (e.g. cofactor binding, changing metal availabilities) which regulate protein metalation in vivo. Here, we outline the fundamental principles and practical considerations that are key to the reliable quantification of metal-protein affinities. We review a selection of spectroscopic probes which can be used to determine protein affinities for essential biological transition metals (including Mn(II), Fe(II), Co(II), Ni(II), Cu(I), Cu(II) and Zn(II)) and, using selected examples, demonstrate how rational probe selection combined with prudent experimental design can be applied to determine accurate KD values.
Topics: Animals; Catalysis; Humans; Metals; Protein Binding; Proteins; Thermodynamics
PubMed: 33710331
DOI: 10.1042/BCJ20200838 -
The Journal of Biological Chemistry Oct 2014The metal binding preferences of most metalloproteins do not match their metal requirements. Thus, metallation of an estimated 30% of metalloenzymes is aided by metal... (Review)
Review
The metal binding preferences of most metalloproteins do not match their metal requirements. Thus, metallation of an estimated 30% of metalloenzymes is aided by metal delivery systems, with ∼ 25% acquiring preassembled metal cofactors. The remaining ∼ 70% are presumed to compete for metals from buffered metal pools. Metallation is further aided by maintaining the relative concentrations of these pools as an inverse function of the stabilities of the respective metal complexes. For example, magnesium enzymes always prefer to bind zinc, and these metals dominate the metalloenzymes without metal delivery systems. Therefore, the buffered concentration of zinc is held at least a million-fold below magnesium inside most cells.
Topics: Bacillus subtilis; Bacterial Proteins; Biological Transport; Clostridium; Cyanobacteria; Escherichia coli; Helicobacter pylori; Iron; Kinetics; Magnesium; Manganese; Metalloproteins; Models, Molecular; Thermodynamics; Zinc
PubMed: 25160626
DOI: 10.1074/jbc.R114.588145 -
Small (Weinheim An Der Bergstrasse,... May 2022Transparent electrodes (TEs) are pivotal components in many modern devices such as solar cells, light-emitting diodes, touch screens, wearable electronic devices, smart... (Review)
Review
Transparent electrodes (TEs) are pivotal components in many modern devices such as solar cells, light-emitting diodes, touch screens, wearable electronic devices, smart windows, and transparent heaters. Recently, the high demand for flexibility and low cost in TEs requires a new class of transparent conductive materials (TCMs), serving as substitutes for the conventional indium tin oxide (ITO). So far, ITO has been the most used TCM despite its brittleness and high cost. Among the different emerging alternative materials to ITO, metallic nanomaterials have received much interest due to their remarkable optical-electrical properties, low cost, ease of manufacturing, flexibility, and widespread applicability. These involve metal grids, thin oxide/metal/oxide multilayers, metal nanowire percolating networks, or nanocomposites based on metallic nanostructures. In this review, a comparison between TCMs based on metallic nanomaterials and other TCM technologies is discussed. Next, the different types of metal-based TCMs developed so far and the fabrication technologies used are presented. Then, the challenges that these TCMs face toward integration in functional devices are discussed. Finally, the various fields in which metal-based TCMs have been successfully applied, as well as emerging and potential applications, are summarized.
Topics: Electric Conductivity; Electrodes; Metals; Nanostructures; Nanowires; Oxides
PubMed: 35195360
DOI: 10.1002/smll.202106006