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\"When you think of nickel, a 5-cent coin probably comes to mind. But nickel is used for so much more than manufacturing coins. Nickel and nickel-containing alloys are very important in our society. Nickel is used in the construction, transportation, power, high-tech and many other industries. This book tells the fascinating story of how nickel was discovered, how ore containing nickel is mined and extracted, the properties that make nickel so useful, and how nickel's many uses and applications make the high-tech world we live in possible. It also provides students with up-to-date resources to continue their research.\"-- Provided by publisher.

Key Points Microbial pathogens require nutrient metals in order to grow and cause disease. However, excess metals are toxic, so metal levels must be tightly regulated during infection. Vertebrates have evolved to exploit this metal dependence and metal toxicity through strategies that either prevent access to nutrient metal or direct excess metals towards invading pathogens. Collectively, these processes are known as nutritional immunity. The struggle between host and pathogen for nutrient metals is best studied in the area of Fe. Fe is sequestered from invading pathogens either intracellularly or in high-affinity Fe-binding proteins. To combat host-mediated Fe sequestration, microbial pathogens elaborate several high-affinity Fe acquisition systems. Recently, vertebrate proteins of the innate immune system have been identified that prevent microbial infection through the chelation of nutrient Mn and Zn. These proteins are members of the S100 family of Ca-binding proteins and are abundant at sites of inflammation. In addition to Mn and Zn sequestration, vertebrates can use strategies to direct toxic levels of Mn and Zn towards microbial pathogens. Bacterial measures to combat Mn and Zn sequestration, as well as the toxicity that is associated with excess levels of these metals, are beginning to be uncovered. It is becoming increasingly evident that host-mediated direction of excess Cu towards microbial pathogens is a crucial aspect of vertebrate defence against infection. This observation has provided an explanation for the broad conservation of Cu detoxification systems across disease-causing microorganisms. The importance of nutritional immunity for defence against infection is highlighted by the observation that inherited defects in transition metal homeostasis dramatically affect host susceptibility to certain infectious diseases. This fact underscores the tremendous therapeutic potential of targeting bacterial metal acquisition systems. Vertebrates protect against infection through the sequestration of nutrient metals, and bacterial pathogens have evolved sophisticated acquisition strategies to circumvent this host defence. In this Review, Hood and Skaar describe this molecular arms race for nutrients. Transition metals occupy an essential niche in biological systems. Their electrostatic properties stabilize substrates or reaction intermediates in the active sites of enzymes, and their heightened reactivity is harnessed for catalysis. However, this heightened activity also renders transition metals toxic at high concentrations. Bacteria, like all living organisms, must regulate their intracellular levels of these elements to satisfy their physiological needs while avoiding harm. It is therefore not surprising that the host capitalizes on both the essentiality and toxicity of transition metals to defend against bacterial invaders. This Review discusses established and emerging paradigms in nutrient metal homeostasis at the pathogen–host interface.

The recent emergence of signaling roles for transition metals presages a broader contribution of these elements beyond their traditional functions as metabolic cofactors. New chemical approaches to identify the sources, targets and physiologies of transition-metal signaling can help expand understanding of the periodic table in a biological context.

The development of transition metal catalysts capable of promoting non-natural transformations within living cells can open significant new avenues in chemical and cell biology. Unfortunately, the complexity of the cell makes it extremely difficult to translate standard organometallic chemistry to living environments. Therefore, progress in this field has been very slow, and many challenges, including the possibility of localizing active metal catalysts into specific subcellular sites or organelles, remain to be addressed. Herein, we report a designed ruthenium complex that accumulates preferentially inside the mitochondria of mammalian cells, while keeping its ability to react with exogenous substrates in a bioorthogonal way. Importantly, we show that the subcellular catalytic activity can be used for the confined release of fluorophores, and even allows selective functional alterations in the mitochondria by the localized transformation of inert precursors into uncouplers of the membrane potential. Due to the complexity of the cell, getting transition metal catalysts localized while retaining their activity is highly challenging. Here, the authors report a ruthenium complex that accumulates in mitochondria and is capable of promoting the confined release of fluorophores or mitochondrial uncouplers.

Fluorescent sensors have emerged as powerful tools in analytical chemistry for the detection and quantification of heavy and transition metal ions in aqueous samples. These metal ions pollute the environment and cause a number of diseases, such as irritability, anaemia, muscle paralysis, neurological damage, and memory loss. Moreover, we explore the wide spectrum of applications in environmental monitoring, where these sensors enable precise detection of contaminants, as well as in biomedical fields, facilitating diagnostic and therapeutic advancements. While highlighting the exceptional progress achieved in this field, I also address the challenges and future prospects for the continued development of fluorescent sensors, emphasizing their potential to shape the future of water quality assessment and analytical chemistry. Heavy and transition metals are of great concern because of their extreme toxicity even at very low concentration and tendency to be accumulated in bodies of living organisms. During the recent years, the design and synthesis of fluorescent chemosensors for sensing environmentally and biologically relevant important metals, particularly for heavy and transition metals, is of great interest. Opon complexation with heavy and transition metals, the fluorescence intensity of these fluorescent chemosensors either quenched or enhanced. The current review paper explains various fluorescent chemosensors for determination of toxic heavy and transition metals in environmental water samples.

Topological insulators are characterized by a non-trivial band topology driven by the spin-orbit coupling. To fully explore the fundamental science and application of topological insulators, material realization is indispensable. Here we predict, based on tight-binding modelling and first-principles calculations, that bilayers of perovskite-type transition-metal oxides grown along the [111] crystallographic axis are potential candidates for two-dimensional topological insulators. The topological band structure of these materials can be fine-tuned by changing dopant ions, substrates and external gate voltages. We predict that LaAuO 3 bilayers have a topologically non-trivial energy gap of about 0.15 eV, which is sufficiently large to realize the quantum spin Hall effect at room temperature. Intriguing phenomena, such as fractional quantum Hall effect, associated with the nearly flat topologically non-trivial bands found in e g systems are also discussed. Topological insulators are a class of materials with an unusual band structure that makes them metallic at the surface and insulating in the bulk. Okamoto and co-workers use electronic structure calculations to predict a new family of possible topological insulators based on transition-metal oxides.

Due to the emergence of multi-drug resistant strains, development of novel antibiotics has become a critical issue. One promising approach is the use of transition metals, since they exhibit rapid and significant toxicity, at low concentrations, in prokaryotic cells. Nevertheless, one main drawback of transition metals is their toxicity in eukaryotic cells. Here, we show that the barriers to use them as therapeutic agents could be mitigated by combining them with silver. We demonstrate that synergism of combinatorial treatments (Silver/transition metals, including Zn, Co, Cd, Ni, and Cu) increases up to 8-fold their antimicrobial effect, when compared to their individual effects, against E. coli and B. subtilis . We find that most combinatorial treatments exhibit synergistic antimicrobial effects at low/non-toxic concentrations to human keratinocyte cells, blast and melanoma rat cell lines. Moreover, we show that silver/(Cu, Ni, and Zn) increase prokaryotic cell permeability at sub-inhibitory concentrations, demonstrating this to be a possible mechanism of the synergistic behavior. Together, these results suggest that these combinatorial treatments will play an important role in the future development of antimicrobial agents and treatments against infections. In specific, the cytotoxicity experiments show that the combinations have great potential in the treatment of topical infections.

Metal ions are vital components in many proteins for the inference and engineering of protein function, with coordination complexity linked to structural, catalytic, or regulatory roles. Modeling transition metal ions, especially in transient, reversible, and concentration-dependent regulatory sites, remains challenging. We present PinMyMetal (PMM), a hybrid machine learning system designed to accurately predict transition metal localization and environment in macromolecules, tailored to tetrahedral and octahedral geometries. PMM outperforms other predictors, achieving high accuracy in ligand and coordinate predictions. It excels in predicting regulatory sites (median deviation 0.36 Å), demonstrating superior accuracy in locating catalytic sites (0.33 Å) and structural sites (0.19 Å). Each predicted site is assigned a certainty score based on local structural and physicochemical features, independent of homologs. Interactive validation through our server, CheckMyMetal, expands PMM’s scope, enabling it to pinpoint and validate diverse functional metal sites from different structure sources (predicted structures, cryo-EM, and crystallography). This facilitates residue-wise assessment and robust metal binding site design. The lightweight PMM system demands minimal computing resources and is available at https://PMM.biocloud.top . The PMM workflow can interrogate with protein sequence to characterize the localization of the most probable transition metals, which is often interchangeable and hard to differentiate by nature. PinMyMetal (PMM) is an accurate tool for predicting transition metal binding sites in proteins. It integrates geometric and chemical features, outperforms existing methods, and supports large-scale genome analysis and drug design.

Flavonoids are natural antibacterial agents, and their bioavailability can be improved by metal complexation. This study examines 3-hydroxyflavone complexes with Co(II), Mn(II), and Zn(II) against Staphylococcus aureus and Escherichia coli . Antibacterial activity and membrane permeability were tested in vitro, while Langmuir monolayers modeled physicochemical interactions with bacterial membranes and their major lipid components. The results demonstrated that, particularly at the highest tested molar ratio, the metal complexes of 3HF exhibited greater antibacterial efficacy than the 3HF independently. Escherichia coli demonstrated greater sensitivity to the tested compounds, than S. aureus . The tested 3HF—complexes were identified as bacteriostatic. In E. coli , both physicochemical and microbiological changes were observed following treatment with Co(II)-3HF and Zn(II)-3HF complexes. In contrast, the Mn(II)-3HF complex affected only model membrane properties without notable microbiological effects. For S. aureus , only the zinc(II) complex showed effective microbiological action on the native cell and activity on the inner membrane (in the model studies), with efficacy ranked as follows: Mn(II)-3HF ≥ Co(II-3HF) > Zn(II)-3HF. Increased permeability of E. coli and S. aureus membranes (in vitro assays) has been proposed as a mechanism for the antibacterial action of the Co(II)-3HF and Zn(II)-3HF complexes.

Transition metal catalysis has contributed to the discovery of novel methodologies and the preparation of natural products, as well as new chances to increase the chemical space in drug discovery programs. In the case of marine drugs, this strategy has been used to achieve selective, sustainable and efficient transformations, which cannot be obtained otherwise. In this perspective, we aim to showcase how a variety of transition metals have provided fruitful couplings in a wide variety of marine drug-like scaffolds over the past few years, by accelerating the production of these valuable molecules.