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Molecules (Basel, Switzerland) Dec 2022Tellurium was successfully incorporated into proteins and applied to protein structure determination through X-ray crystallography. However, studies on tellurium... (Review)
Review
Tellurium was successfully incorporated into proteins and applied to protein structure determination through X-ray crystallography. However, studies on tellurium modification of DNA and RNA are limited. This review highlights the recent development of Te-modified nucleosides, nucleotides, and nucleic acids, and summarizes the main synthetic approaches for the preparation of 5-PhTe, 2'-MeTe, and 2'-PhTe modifications. Those modifications are compatible with solid-phase synthesis and stable during Te-oligonucleotide purification. Moreover, the ideal electronic and atomic properties of tellurium for generating clear isomorphous signals give Te-modified DNA and RNA great potential applications in 3D crystal structure determination through X-ray diffraction. STM study also shows that Te-modified DNA has strong topographic and current peaks, which immediately suggests potential applications in nucleic acid direct imaging, nanomaterials, molecular electronics, and diagnostics. Theoretical studies indicate the potential application of Te-modified nucleosides in cancer therapy.
Topics: Tellurium; Nucleotides; Nucleic Acids; Nucleosides; DNA; RNA
PubMed: 36500495
DOI: 10.3390/molecules27238379 -
International Journal of Molecular... May 2021Metalloid tellurium is characterized as a chemical element belonging to the chalcogen group without known biological function. However, its compounds, especially the... (Review)
Review
Metalloid tellurium is characterized as a chemical element belonging to the chalcogen group without known biological function. However, its compounds, especially the oxyanions, exert numerous negative effects on both prokaryotic and eukaryotic organisms. Recent evidence suggests that increasing environmental pollution with tellurium has a causal link to autoimmune, neurodegenerative and oncological diseases. In this review, we provide an overview about the current knowledge on the mechanisms of tellurium compounds' toxicity in bacteria and humans and we summarise the various ways organisms cope and detoxify these compounds. Over the last decades, several gene clusters conferring resistance to tellurium compounds have been identified in a variety of bacterial species and strains. These genetic determinants exhibit great genetic and functional diversity. Besides the existence of specific resistance mechanisms, tellurium and its toxic compounds interact with molecular systems, mediating general detoxification and mitigation of oxidative stress. We also discuss the similarity of tellurium and selenium biochemistry and the impact of their compounds on humans.
Topics: Anions; Bacteria; Environmental Pollution; Eukaryotic Cells; Humans; Oxidative Stress; Prokaryotic Cells; Selenium; Tellurium
PubMed: 34072929
DOI: 10.3390/ijms22115924 -
Oxidative Medicine and Cellular... 2019Tellurium is a rare element that has been regarded as a toxic, nonessential element, and its biological role is not clearly established. In addition, the biological... (Review)
Review
Tellurium is a rare element that has been regarded as a toxic, nonessential element, and its biological role is not clearly established. In addition, the biological effects of elemental tellurium and some of its organic and inorganic derivatives have been studied, leading to a set of interesting and promising applications. Diphenyl ditelluride (DPDT), an organic tellurium derivate, showed antioxidant, antigenotoxic, antimutagenic, and anticancer properties. The antioxidant and prooxidant properties of DPDT are complex and depend on experimental conditions, which may explain the contradictory reports of these properties. In addition, DPDT may exert its effects through different pathways, including distinct ones to those responsible for chemotherapy resistance phenotypes: transcription factors, membrane receptors, adhesion, structural molecules, cell cycle regulatory components, and apoptosis pathways. This review aims to present recent advances in our understanding of the biological effects, therapeutic potential, and safety of DPDT treatment. Moreover, original results demonstrating the cytotoxic effects of DPDT in different mammalian cell lines and systems biology analysis are included, and emerging approaches for possible future applications are inferred.
Topics: Antioxidants; Benzene Derivatives; Humans; Organometallic Compounds; Oxidation-Reduction; Tellurium
PubMed: 31772702
DOI: 10.1155/2019/2510936 -
International Journal of Molecular... Jan 2021The synthesis and assembly of nanoparticles using green technology has been an excellent option in nanotechnology because they are easy to implement, cost-efficient,... (Review)
Review
The synthesis and assembly of nanoparticles using green technology has been an excellent option in nanotechnology because they are easy to implement, cost-efficient, eco-friendly, risk-free, and amenable to scaling up. They also do not require sophisticated equipment nor well-trained professionals. Bionanotechnology involves various biological systems as suitable nanofactories, including biomolecules, bacteria, fungi, yeasts, and plants. Biologically inspired nanomaterial fabrication approaches have shown great potential to interconnect microbial or plant extract biotechnology and nanotechnology. The present article extensively reviews the eco-friendly production of metalloid nanoparticles, namely made of selenium (SeNPs) and tellurium (TeNPs), using various microorganisms, such as bacteria and fungi, and plants' extracts. It also discusses the methodologies followed by materials scientists and highlights the impact of the experimental sets on the outcomes and shed light on the underlying mechanisms. Moreover, it features the unique properties displayed by these biogenic nanoparticles for a large range of emerging applications in medicine, agriculture, bioengineering, and bioremediation.
Topics: Animals; Green Chemistry Technology; Humans; Industrial Microbiology; Metal Nanoparticles; Nanomedicine; Selenium; Tellurium
PubMed: 33498184
DOI: 10.3390/ijms22030989 -
Applied Microbiology and Biotechnology Sep 2019The fungi Aureobasidium pullulans, Mortierella humilis, Trichoderma harzianum and Phoma glomerata were used to investigate the formation of selenium- and...
The fungi Aureobasidium pullulans, Mortierella humilis, Trichoderma harzianum and Phoma glomerata were used to investigate the formation of selenium- and tellurium-containing nanoparticles during growth on selenium- and tellurium-containing media. Most organisms were able to grow on both selenium- and tellurium-containing media at concentrations of 1 mM resulting in extensive precipitation of elemental selenium and tellurium on fungal surfaces as observed by the red and black colour changes. Red or black deposits were confirmed as elemental selenium and tellurium, respectively. Selenium oxide and tellurium oxide were also found after growth of Trichoderma harzianum with 1 mM selenite and tellurite as well as the formation of elemental selenium and tellurium. The hyphal matrix provided nucleation sites for metalloid deposition with extracellular protein and extracellular polymeric substances localizing the resultant Se or Te nanoparticles. These findings are relevant to remedial treatments for selenium and tellurium and to novel approaches for selenium and tellurium biorecovery.
Topics: Biodegradation, Environmental; Fungi; Nanoparticles; Oxidation-Reduction; Selenium; Selenium Compounds; Tellurium
PubMed: 31324941
DOI: 10.1007/s00253-019-09995-6 -
Drug Resistance Updates : Reviews and... Jul 2022Selenium is an essential trace element that is crucial for cellular antioxidant defense against reactive oxygen species (ROS). Recently, many selenium-containing... (Review)
Review
Selenium is an essential trace element that is crucial for cellular antioxidant defense against reactive oxygen species (ROS). Recently, many selenium-containing compounds have exhibited a wide spectrum of biological activities that make them promising scaffolds in Medicinal Chemistry, and, in particular, in the search for novel compounds with anticancer activity. Similarly, certain tellurium-containing compounds have also exhibited substantial biological activities. Here we provide an overview of the biological activities of seleno- and tellurocompounds including chemopreventive activity, antioxidant or pro-oxidant activity, modulation of the inflammatory processes, induction of apoptosis, modulation of autophagy, inhibition of multidrug efflux pumps such as P-gp, inhibition of cancer metastasis, selective targeting of tumors and enhancement of the cytotoxic activity of chemotherapeutic drugs, as well as overcoming tumor drug resistance. A review of the chemistry of the most relevant seleno- or tellurocompounds with activity against resistant cancers is also presented, paying attention to the synthesis of these compounds and to the preparation of bioactive selenium or tellurium nanoparticles. Based on these data, the use of these seleno- and tellurocompounds is a promising approach in the development of strategies that can drive forward the search for novel therapies or adjuvants of current therapies against drug-resistant cancers.
Topics: Antineoplastic Agents; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; Nanoparticles; Neoplasms; Reactive Oxygen Species; Selenium; Tellurium
PubMed: 35533630
DOI: 10.1016/j.drup.2022.100844 -
Journal of X-ray Science and Technology 2018Recent advances in photon counting detection technology have led to significant research interest in X-ray imaging. (Review)
Review
BACKGROUND
Recent advances in photon counting detection technology have led to significant research interest in X-ray imaging.
OBJECTIVE
As a tutorial level review, this paper covers a wide range of aspects related to X-ray photon counting detector characterization.
METHODS
The tutorial begins with a detailed description of the working principle and operating modes of a pixelated X-ray photon counting detector with basic architecture and detection mechanism. Currently available methods and techniques for charactering major aspects including energy response, noise floor, energy resolution, count rate performance (detector efficiency), and charge sharing effect of photon counting detectors are comprehensively reviewed. Other characterization aspects such as point spread function (PSF), line spread function (LSF), contrast transfer function (CTF), modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), bias voltage, radiation damage, and polarization effect are also remarked.
RESULTS
A cadmium telluride (CdTe) pixelated photon counting detector is employed for part of the characterization demonstration and the results are presented.
CONCLUSIONS
This review can serve as a tutorial for X-ray imaging researchers and investigators to understand, operate, characterize, and optimize photon counting detectors for a variety of applications.
Topics: Cadmium Compounds; Calibration; Equipment Design; Photons; Signal Processing, Computer-Assisted; Spectrometry, X-Ray Emission; Tellurium; X-Rays
PubMed: 29154310
DOI: 10.3233/XST-16210 -
The Journal of Organic Chemistry Apr 2022Phenoxazines, in particular N-arylated phenoxazines, represent an increasingly important scaffold in the material sciences. Moreover, the oxygen-gas-mediated...
Phenoxazines, in particular N-arylated phenoxazines, represent an increasingly important scaffold in the material sciences. Moreover, the oxygen-gas-mediated dehydrogenative phenochalcogenazination concept of phenols has been developed and exemplified for X = sulfur and recently for X = selenium and tellurium. The smallest chalcogen, X = oxygen, is herein exemplified with various functional groups under a likewise trivial oxygen atmosphere.
Topics: Oxygen; Phenols; Selenium; Sulfur; Tellurium
PubMed: 35276045
DOI: 10.1021/acs.joc.1c02827 -
Scientific Reports Apr 2022Neutron Capture Enhanced Particle Therapy (NCEPT) boosts the effectiveness of particle therapy by capturing thermal neutrons produced by beam-target nuclear interactions...
Neutron Capture Enhanced Particle Therapy (NCEPT) boosts the effectiveness of particle therapy by capturing thermal neutrons produced by beam-target nuclear interactions in and around the treatment site, using tumour-specific [Formula: see text]B or [Formula: see text]Gd-based neutron capture agents. Neutron captures release high-LET secondary particles together with gamma photons with energies of 478 keV or one of several energies up to 7.94 MeV, for [Formula: see text]B and [Formula: see text]Gd, respectively. A key requirement for NCEPT's translation is the development of in vivo dosimetry techniques which can measure both the direct ion dose and the dose due to neutron capture. In this work, we report signatures which can be used to discriminate between photons resulting from neutron capture and those originating from other processes. A Geant4 Monte Carlo simulation study into timing and energy thresholds for discrimination of prompt gamma photons resulting from thermal neutron capture during NCEPT was conducted. Three simulated [Formula: see text] mm[Formula: see text] cubic PMMA targets were irradiated by [Formula: see text]He or [Formula: see text]C ion beams with a spread out Bragg peak (SOBP) depth range of 60 mm; one target is homogeneous while the others include [Formula: see text] mm[Formula: see text] neutron capture inserts (NCIs) of pure [Formula: see text]B or [Formula: see text]Gd located at the distal edge of the SOBP. The arrival times of photons and neutrons entering a simulated [Formula: see text] mm[Formula: see text] ideal detector were recorded. A temporal mask of 50-60 ns was found to be optimal for maximising the discrimination of the photons resulting from the neutron capture by boron and gadolinium. A range of candidate detector and thermal neutron shielding materials were simulated, and detections meeting the proposed acceptance criteria (i.e. falling within the target energy window and arriving 60 ns post beam-off) were classified as true or false positives, depending on their origin. The ratio of true/false positives ([Formula: see text]) was calculated; for targets with [Formula: see text]B and [Formula: see text]Gd NCIs, the detector materials which resulted in the highest [Formula: see text] were cadmium-shielded CdTe and boron-shielded LSO, respectively. The optimal irradiation period for both carbon and helium ions was 1 µs for the [Formula: see text]B NCI and 1 ms for the [Formula: see text]Gd NCI.
Topics: Boron; Cadmium Compounds; Monte Carlo Method; Neutrons; Quantum Dots; Tellurium
PubMed: 35393505
DOI: 10.1038/s41598-022-09676-x -
World Journal of Microbiology &... Jul 2023Tellurium is a super-trace metalloid on Earth. Owing to its excellent physical and chemical properties, it is used in industries such as metallurgy and manufacturing,... (Review)
Review
Tellurium is a super-trace metalloid on Earth. Owing to its excellent physical and chemical properties, it is used in industries such as metallurgy and manufacturing, particularly of semiconductors and - more recently - solar panels. As the global demand for tellurium rises, environmental issues surrounding tellurium have recently aroused concern due to its high toxicity. The amount of tellurium released to the environment is increasing, and microorganisms play an important role in the biogeochemical cycling of environmental tellurium. This review focuses on novel developments on tellurium transformations driven by microbes and includes the following sections: (1) history and applications of tellurium; (2) toxicity of tellurium; (3) microbial detoxification mechanisms against soluble tellurium anions including uptake, efflux and methods of reduction, and reduced ability to cope with oxidation stress or repair damaged DNA; and (4) the characteristics and applications of tellurium nanoparticles (TeNPs) produced by microbes. This review raises the awareness of microorganisms in tellurium biogeochemical cycling and the growing applications for microbial tellurium nanoparticles.
Topics: Trace Elements; Tellurium; Nanoparticles
PubMed: 37507604
DOI: 10.1007/s11274-023-03704-2