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Current Environmental Health Reports Sep 2023Biomarkers are commonly used in epidemiological studies to assess metals and metalloid exposure and estimate internal dose, as they integrate multiple sources and routes... (Review)
Review
PURPOSE OF REVIEW
Biomarkers are commonly used in epidemiological studies to assess metals and metalloid exposure and estimate internal dose, as they integrate multiple sources and routes of exposure. Researchers are increasingly using multi-metal panels and innovative statistical methods to understand how exposure to real-world metal mixtures affects human health. Metals have both common and unique sources and routes of exposure, as well as biotransformation and elimination pathways. The development of multi-element analytical technology allows researchers to examine a broad spectrum of metals in their studies; however, their interpretation is complex as they can reflect different windows of exposure and several biomarkers have critical limitations. This review elaborates on more than 500 scientific publications to discuss major sources of exposure, biotransformation and elimination, and biomarkers of exposure and internal dose for 12 metals/metalloids, including 8 non-essential elements (arsenic, barium, cadmium, lead, mercury, nickel, tin, uranium) and 4 essential elements (manganese, molybdenum, selenium, and zinc) commonly used in multi-element analyses.
RECENT FINDINGS
We conclude that not all metal biomarkers are adequate measures of exposure and that understanding the metabolic biotransformation and elimination of metals is key to metal biomarker interpretation. For example, whole blood is a good biomarker of exposure to arsenic, cadmium, lead, mercury, and tin, but it is not a good indicator for barium, nickel, and uranium. For some essential metals, the interpretation of whole blood biomarkers is unclear. Urine is the most commonly used biomarker of exposure across metals but it should not be used to assess lead exposure. Essential metals such as zinc and manganese are tightly regulated by homeostatic processes; thus, elevated levels in urine may reflect body loss and metabolic processes rather than excess exposure. Total urinary arsenic may reflect exposure to both organic and inorganic arsenic, thus, arsenic speciation and adjustment for arsebonetaine are needed in populations with dietary seafood consumption. Hair and nails primarily reflect exposure to organic mercury, except in populations exposed to high levels of inorganic mercury such as in occupational and environmental settings. When selecting biomarkers, it is also critical to consider the exposure window of interest. Most populations are chronically exposed to metals in the low-to-moderate range, yet many biomarkers reflect recent exposures. Toenails are emerging biomarkers in this regard. They are reliable biomarkers of long-term exposure for arsenic, mercury, manganese, and selenium. However, more research is needed to understand the role of nails as a biomarker of exposure to other metals. Similarly, teeth are increasingly used to assess lifelong exposures to several essential and non-essential metals such as lead, including during the prenatal window. As metals epidemiology moves towards embracing a multi-metal/mixtures approach and expanding metal panels to include less commonly studied metals, it is important for researchers to have a strong knowledge base about the metal biomarkers included in their research. This review aims to aid metals researchers in their analysis planning, facilitate sound analytical decision-making, as well as appropriate understanding and interpretation of results.
Topics: Pregnancy; Female; Humans; Cadmium; Arsenic; Manganese; Selenium; Nickel; Barium; Uranium; Tin; Zinc; Mercury; Biomarkers
PubMed: 37337116
DOI: 10.1007/s40572-023-00402-x -
Molecules (Basel, Switzerland) Oct 2023This contribution describes the path of my nearly forty-year quest to understand the special ligand coordinated to molybdenum and tungsten ions in their respective... (Review)
Review
This contribution describes the path of my nearly forty-year quest to understand the special ligand coordinated to molybdenum and tungsten ions in their respective enzymes. Through this quest, I aimed to discover why nature did not simply use a methyl group on the dithiolene that chelates Mo and W but instead chose a complicated pyranopterin. My journey sought answers through the synthesis of model Mo compounds that allowed systematic investigations of the interactions between molybdenum and pterin and molybdenum and pterin-dithiolene and revealed special features of the pyranopterin dithiolene chelate bound to molybdenum.
PubMed: 37959716
DOI: 10.3390/molecules28217296 -
IUCrData Aug 2023The title cluster compound, [Mo(η-CHMe)(μ-Se)], was synthesized from the reaction of [Mo(η-CHMe)(CO)] with grey selenium in refluxing xylene solution under a...
The title cluster compound, [Mo(η-CHMe)(μ-Se)], was synthesized from the reaction of [Mo(η-CHMe)(CO)] with grey selenium in refluxing xylene solution under a nitro-gen atmosphere. The complete cluster is generated by a crystallographic twofold axis and contains an MoSe cubane-like core surrounded by four η-methylcyclo-pentadienyl ligands. In the core, the four molybdenum atoms are connected to each other to form a tetra-hedron, with a selenium atom capping each face. The Mo-Mo bond lengths vary from 2.9857 (5) to 3.0083 (3) Å and the Mo-Se separations range from 2.4633 (4) to 2.4693 (5) Å.
PubMed: 37693785
DOI: 10.1107/S2414314623006570 -
Molecules (Basel, Switzerland) Dec 2023Only a single enzyme system-nitrogenase-carries out the conversion of atmospheric N into bioavailable ammonium, an essential prerequisite for all organismic life. The... (Review)
Review
Only a single enzyme system-nitrogenase-carries out the conversion of atmospheric N into bioavailable ammonium, an essential prerequisite for all organismic life. The reduction of this inert substrate at ambient conditions poses unique catalytic challenges that strain our mechanistic understanding even after decades of intense research. Structural biology has added its part to this greater tapestry, and in this review, I provide a personal (and highly biased) summary of the parts of the story to which I had the privilege to contribute. It focuses on the crystallographic analysis of the three isoforms of nitrogenases at high resolution and the binding of ligands and inhibitors to the active-site cofactors of the enzyme. In conjunction with the wealth of available biochemical, biophysical, and spectroscopic data on the protein, this has led us to a mechanistic hypothesis based on an elementary mechanism of repetitive hydride formation and insertion.
Topics: Nitrogenase; Nitrogen Fixation; Catalysis; Molybdenum; Nitrogen
PubMed: 38138449
DOI: 10.3390/molecules28247959 -
BME Frontiers 2023The wide and frequent use of antibiotics in the treatment of bacterial infection can cause the occurrence of multidrug-resistant bacteria, which becomes a serious health... (Review)
Review
The wide and frequent use of antibiotics in the treatment of bacterial infection can cause the occurrence of multidrug-resistant bacteria, which becomes a serious health threat. Therefore, it is necessary to develop antibiotic-independent treatment modalities. Chemodynamic therapy (CDT) is defined as the approach employing Fenton and/or Fenton-like reactions for generating hydroxyl radical (•OH) that can kill target cells. Recently, CDT has been successfully employed for antibacterial applications. Apart from the common Fe-mediated CDT strategy, antibacterial CDT strategies mediated by other metal elements such as copper, manganese, cobalt, molybdenum, platinum, tungsten, nickel, silver, ruthenium, and zinc have also been proposed. Furthermore, different types of materials like nanomaterials and hydrogels can be adopted for constructing CDT-involved antibacterial platforms. Besides, CDT can introduce some toxic metal elements and then achieve synergistic antibacterial effects together with reactive oxygen species. Finally, CDT can be combined with other therapies such as starvation therapy, phototherapy, and sonodynamic therapy for achieving improved antibacterial performance. This review first summarizes the advancements in antibacterial CDT and then discusses the present limitations and future research directions in this field, hoping to promote the development of more effective materials and strategies for achieving potentiated CDT.
PubMed: 37849674
DOI: 10.34133/bmef.0021 -
Molecules (Basel, Switzerland) Jul 2023Mo/W-containing formate dehydrogenases (FDH) catalyzes the reversible oxidation of formate to carbon dioxide at their molybdenum or tungsten active sites. The... (Review)
Review
Mo/W-containing formate dehydrogenases (FDH) catalyzes the reversible oxidation of formate to carbon dioxide at their molybdenum or tungsten active sites. The metal-containing FDHs are members of the dimethylsulfoxide reductase family of mononuclear molybdenum cofactor (Moco)- or tungsten cofactor (Wco)-containing enzymes. In these enzymes, the active site in the oxidized state comprises a Mo or W atom present in the bis-Moco, which is coordinated by the two dithiolene groups from the two MGD moieties, a protein-derived SeCys or Cys, and a sixth ligand that is now accepted as being a sulfido group. SeCys-containing enzymes have a generally higher turnover number than Cys-containing enzymes. The analogous chemical properties of W and Mo, the similar active sites of W- and Mo-containing enzymes, and the fact that W can replace Mo in some enzymes have led to the conclusion that Mo- and W-containing FDHs have the same reaction mechanism. Details of the catalytic mechanism of metal-containing formate dehydrogenases are still not completely understood and have been discussed here.
Topics: Formate Dehydrogenases; Oxidation-Reduction; Metalloproteins; Molybdenum; Catalytic Domain; Pteridines; Coenzymes
PubMed: 37513211
DOI: 10.3390/molecules28145338 -
Langmuir : the ACS Journal of Surfaces... Mar 2024Deposition of molybdenum disulfide (MoS) coatings using physical vapor deposition (PVD) and mechanical burnishing has been widely assessed for solid lubricants in space...
Deposition of molybdenum disulfide (MoS) coatings using physical vapor deposition (PVD) and mechanical burnishing has been widely assessed for solid lubricants in space applications but still suffers from line-of-sight constraints on complex geometries. Here, we highlight one of the first demonstrations of electrodeposited MoSO and MoSO/Ni thin-film coatings from aqueous solutions of ammonium tetrathiomolybdate for solid lubricant applications and their remarkable ability to provide low coefficients of friction and high wear resistance. Characterization of the coating morphology shows amorphous microstructures with a high oxygen content and cracking upon drying. Even so, electrodeposited MoSO can achieve low steady-state coefficients of friction (μ ∼ 0.05-0.06) and wear rates (2.6 × 10 mm/(N m)) approaching those of physical vapor deposited coatings (2.3 × 10 mm/(N m)). Additionally, we show that adding dopants such as nickel increased the wear rate (7.5 × 10 mm/(N m)) and initial coefficient of friction (μ = 0.23) due to compositional modifications such as dramatic sub-stoichiometry (S/Mo ∼ 1) and expression of a NiO surface layer, although doping did reduce the degree of cracking upon drying.
PubMed: 38456666
DOI: 10.1021/acs.langmuir.3c03518 -
ACS Omega Oct 2023During the past decade, two-dimensional (2D) layered materials opened novel opportunities for the exploration of exciting new physics and devices owing to their physical...
During the past decade, two-dimensional (2D) layered materials opened novel opportunities for the exploration of exciting new physics and devices owing to their physical and electronic properties. Among 2D materials, iron selenide has attracted much attention from several physicists as they provide a fruitful stage for developing new superconductors. Chemical doping offers a powerful approach to manipulate and optimize the electronic structure and physical properties of materials. Here, to reveal how doping affects the physical properties in FeSe, we report on complementary measurements of molybdenum- and sulfur-doped FeSe with theoretical calculations. MoFeSeS was synthesized by a one-step solid-state reaction method. Crystal structure and morphology were studied using powder X-ray diffraction and scanning electron microscopy. Thermal stability and decomposition behavior in doped samples were studied by thermogravimetric analysis, and to understand the microscopic influence of doping, we performed Raman spectroscopy. First-principles calculations of the electronic structure illustrate distinct changes of electronic structures of the substituted FeSe systems, which can be responsible for their superconducting properties.
PubMed: 37810706
DOI: 10.1021/acsomega.3c05684 -
Nutrients Jul 2023Molybdenum is an essential trace element for human health and survival, with molybdenum-containing enzymes catalysing multiple reactions in the metabolism of purines,... (Review)
Review
Molybdenum is an essential trace element for human health and survival, with molybdenum-containing enzymes catalysing multiple reactions in the metabolism of purines, aldehydes, and sulfur-containing amino acids. Recommended daily intakes vary globally, with molybdenum primarily sourced through the diet, and supplementation is not common. Although the benefits of molybdenum as an anti-diabetic and antioxidant inducer have been reported in the literature, there are conflicting data on the benefits of molybdenum for chronic diseases. Overexposure and deficiency can result in adverse health outcomes and mortality, although physiological doses remain largely unexplored in relation to human health. The lack of knowledge surrounding molybdenum intake and the role it plays in physiology is compounded during pregnancy. As pregnancy progresses, micronutrient demand increases, and diet is an established factor in programming gestational outcomes and maternal health. This review summarises the current literature concerning varied recommendations on molybdenum intake, the role of molybdenum and molybdoenzymes in physiology, and the contribution these play in gestational outcomes.
Topics: Pregnancy; Female; Humans; Placenta; Micronutrients; Trace Elements; Molybdenum; Dietary Supplements; Pregnancy Complications; Pregnancy Outcome
PubMed: 37571285
DOI: 10.3390/nu15153348