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Bioconjugate Chemistry Jan 2023The ability to control the assembly of mixed-dimensional heterostructures with nanoscale control is key for the fabrication of novel nanohybrid systems with new...
The ability to control the assembly of mixed-dimensional heterostructures with nanoscale control is key for the fabrication of novel nanohybrid systems with new functionalities, particularly for optoelectronics applications. Herein we report a strategy to control the assembly of heterostructures and tune their electronic coupling employing DNA as a linker. We functionalized MoS nanosheets (NSs) with biotin-terminated dsDNA employing three different chemical strategies, namely, thiol, maleimide, and aryl diazonium. This allowed us to then tether streptavidinated quantum dots (QDs) to the DNA functionalized MoS surface via biotin-avidin recognition. Nanoscale control over the separation between QDs and NSs was achieved by varying the number of base pairs (bp) constituting the DNA linker, between 10, 20, and 30 bp, corresponding to separations of 3.4, 6.8, and 13.6 nm, respectively. Spectroscopic data confirmed the successful functionalization, while atomic force and transmission electron microscopy were employed to image the nanohybrids. In solution steady-state and time-resolved photoluminescence demonstrated the electronic coupling between the two nanostructures, that in turn was observed to progressively scale as a function of DNA linker employed and hence distance between the two nanomoieties in the hybrids.
Topics: Quantum Dots; Molybdenum; Biotin; Nanostructures; DNA
PubMed: 35969686
DOI: 10.1021/acs.bioconjchem.2c00285 -
Molecules (Basel, Switzerland) Jun 2022Molybdenum (Mo) is an essential trace element in all kingdoms of life. Mo is bioavailable as the oxyanion molybdate and gains biological activity in eukaryotes when...
Molybdenum (Mo) is an essential trace element in all kingdoms of life. Mo is bioavailable as the oxyanion molybdate and gains biological activity in eukaryotes when bound to molybdopterin, forming the molybdenum cofactor. The imbalance of molybdate homeostasis results in growth deficiencies or toxic symptoms within plants, fungi and animals. Recently, fluorescence resonance energy transfer (FRET) methods have emerged, monitoring cellular and subcellular molybdate distribution dynamics using a genetically encoded molybdate-specific FRET nanosensor, named MolyProbe. Here, we show that the MolyProbe system is a fast and reliable in vitro assay for quantitative molybdate determination. We added a Strep-TagII affinity tag to the MolyProbe protein for quick and easy purification. This MolyProbe is highly stable, resistant to freezing and can be stored for several weeks at 4 °C. Furthermore, the molybdate sensitivity of the assay peaked at low nM levels. Additionally, The MolyProbe was applied in vitro for quantitative molybdate determination in cell extracts of the plant , the fungus and the yeast . Our results show the functionality of the molybdate transporter MOT1.1 and indicate that FRET-based molybdate detection is an excellent tool for measuring bioavailable Mo.
Topics: Anion Transport Proteins; Arabidopsis; Arabidopsis Proteins; Fluorescence Resonance Energy Transfer; Molybdenum; Neurospora crassa; Saccharomyces cerevisiae
PubMed: 35744816
DOI: 10.3390/molecules27123691 -
Nano Letters Jul 2021We present the discovery of a charge density wave (CDW) ground state in heavily electron-doped molybdenum disulfide (MoS). This is the first observation of a CDW in any...
We present the discovery of a charge density wave (CDW) ground state in heavily electron-doped molybdenum disulfide (MoS). This is the first observation of a CDW in any (column 6) transition metal dichalcogenide (TMD). The band structure of MoS is distinct from the and TMDs in which CDWs have been previously observed, facilitating new insight into CDW formation. We demonstrate a metal-insulator transition at 85 K, a 25 meV gap at the Fermi level, and two distinct CDW modulations, (2√3 × 2√3) R30° and 2 × 2, attributable to Fermi surface nesting (FSN) and electron-phonon coupling (EPC), respectively. This simultaneous exhibition of FSN and EPC CDW modulations is unique among observations of CDW ground states, and we discuss this in the context of band folding. Our observations provide a route toward the resolution of controversies surrounding the origin of CDW modulations in TMDs.
Topics: Disulfides; Electrons; Molybdenum
PubMed: 34228455
DOI: 10.1021/acs.nanolett.1c00677 -
Journal of Applied Microbiology Nov 2018To investigate the capabilities of different types of biosurfactants (rhamnolipids, lipopeptides, sophorolipids) to remove metals and carbon from the hazardous spent...
AIMS
To investigate the capabilities of different types of biosurfactants (rhamnolipids, lipopeptides, sophorolipids) to remove metals and carbon from the hazardous spent hydrodesulphurization (HDS) catalyst generated by petroleum refineries.
METHODS AND RESULTS
Biosurfactants were prepared and used to treat spent HDS catalyst. Metal and carbon contents were analysed and compared with those from no-biosurfactant control treatments. All biosurfactant treatments increased carbon loss percentage from the spent HDS catalyst. The lipopeptide treatment LI, containing 17·34 mg ml of crude biosurfactants, caused the highest carbon loss percentage (44·5%). Rhamnolipids were, in general, better than sophorolipids and lipopeptides as metal-removing agents. The metal content decreased as the concentration of rhamnolipids decreased. The R5 treatment, which contained 0·4 mg l of crude rhamnolipids, caused the highest reduction in metal content. Molybdenum, nickle and vanadium contents were reduced by 90, 30 and 70% respectively.
CONCLUSIONS
Biosurfactants might have potential application for metals and coke removal from spent HDS catalysts. The bioleaching capability depends on the type and concentration of the biosurfactant.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study, after further in-depth investigations, might lead to the development of an eco-friendly and economic technology to treat or even regenerate the environmentally hazardous spent HDS catalysts, which are generated in huge amounts by the petroleum refineries.
Topics: Bacillus megaterium; Candida; Catalysis; Glycolipids; Lipopeptides; Metals; Molybdenum; Nickel; Petroleum Pollution; Pseudomonas aeruginosa; Surface-Active Agents; Vanadium
PubMed: 29964351
DOI: 10.1111/jam.14036 -
PloS One 2013The use of dried and re-hydrated biomass of the seagrass Posidonia oceanica was investigated as an alternative and -low-cost biomaterial for removal of vanadium(III) and...
The use of dried and re-hydrated biomass of the seagrass Posidonia oceanica was investigated as an alternative and -low-cost biomaterial for removal of vanadium(III) and molybdenum(V) from wastewaters. Initial characterisation of this biomaterial identified carboxylic groups on the cuticle as potentially responsible for cation sorption, and confirmed the toxic-metal bioaccumulation. The combined effects on biosorption performance of equilibrium pH and metal concentrations were investigated in an ideal single-metal system and in more real-life multicomponent systems. There were either with one metal (vanadium or molybdenum) and sodium nitrate, as representative of high ionic strength systems, or with the two metals (vanadium and molybdenum). For the single-metal solutions, the optimum was at pH 3, where a significant proportion of vanadium was removed (ca. 70%) while there was ca. 40% adsorption of molybdenum. The data obtained from the more real-life multicomponent systems showed that biosorption of one metal was improved both by the presence of the other metal and by high ionic strength, suggesting a synergistic effect on biosorption rather than competition. There data ware used for the development of a simple multi-metal equilibrium model based on the non-competitive Langmuir approach, which was successfully fitted to experimental data and represents a useful support tool for the prediction of biosorption performance in such real-life systems. Overall, the results suggest that biomass of P. oceanica can be used as an efficient biosorbent for removal of vanadium(III) and molybdenum(V) from aqueous solutions. This process thus offers an eco-compatible solution for the reuse of the waste material of leaves that accumulate on the beach due to both human activities and to storms at sea.
Topics: Adsorption; Algorithms; Biomass; Hydrogen-Ion Concentration; Models, Chemical; Molybdenum; Reproducibility of Results; Thermodynamics; Tracheophyta; Vanadium; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical; Water Purification
PubMed: 24204692
DOI: 10.1371/journal.pone.0076870 -
Ecotoxicology and Environmental Safety May 2023The rapid development of nanotechnology has aroused considerable attentions toward understanding the effects of engineered nanomaterials (ENMs) on the propagation of...
The rapid development of nanotechnology has aroused considerable attentions toward understanding the effects of engineered nanomaterials (ENMs) on the propagation of antibiotic resistance. Molybdenum disulfide (MoS) is an extensively used ENM and poses potential risks associated with environmental exposure; nevertheless, the role of MoS toward antibiotic resistance genes (ARGs) transfer remains largely unknown. Herein, it was discovered that MoS nanosheets accelerated the horizontal transfer of RP4 plasmid across Escherichia coli in a dose-dependent manner (0.5-10 mg/L), with the maximum transfer frequency 2.07-fold higher than that of the control. Integration of physiological, transcriptomics, and metabolomics analyses demonstrated that SOS response in bacteria was activated by MoS due to the elevation of oxidative damage, accompanied by cell membrane permeabilization. MoS promoted bacterial adhesion and intercellular contact via stimulating the secretion of extracellular polysaccharides. The ATP levels were maximally increased by 305.7 % upon exposure to MoS, and the expression of plasmid transfer genes was up-regulated, contributing to the accelerated plasmid conjugation and increased ARG abundance in soil. Our findings highlight the roles of emerging ENMs (e.g., MoS) in ARGs dissemination, which is significant for the safe applications and risk management of ENMs under the development scenarios of nanotechnology.
Topics: Anti-Bacterial Agents; Molybdenum; Genes, Bacterial; Soil; Gene Transfer, Horizontal; Drug Resistance, Microbial; Escherichia coli; Plasmids
PubMed: 37062264
DOI: 10.1016/j.ecoenv.2023.114913 -
Angewandte Chemie (International Ed. in... Oct 2014The molybdenum and vanadium nitrogenases are two homologous enzymes with distinct structural and catalytic features. Previously, it was demonstrated that the...
The molybdenum and vanadium nitrogenases are two homologous enzymes with distinct structural and catalytic features. Previously, it was demonstrated that the V nitrogenase was nearly 700 times more active than its Mo counterpart in reducing CO to hydrocarbons. Herein, a similar discrepancy between the two nitrogenases in the reduction of CO2 is reported, with the V nitrogenase being capable of reducing CO2 to CO, CD4, C2D4, and C2D6, and its Mo counterpart only capable of reducing CO2 to CO. Furthermore, it is shown that the V nitrogenase may direct the formation of CD4 in part via CO2-derived CO, but that it does not catalyze the formation of C2D4 and C2D6 along this route. The exciting observation of a V nitrogenase-catalyzed C-C coupling with CO2 as the origin of the building blocks adds another interesting reaction to the catalytic repertoire of this unique enzyme system. The differential activities of the V and Mo nitrogenases in CO2 reduction provide an important framework for systematic investigations of this reaction in the future.
Topics: Carbon Dioxide; Molybdenum; Nitrogenase; Oxidation-Reduction
PubMed: 25205285
DOI: 10.1002/anie.201406863 -
Environmental Science and Pollution... Sep 2021Some regions of Argentina are affected by high concentrations of molybdenum, arsenic and vanadium from natural sources in their groundwater. In particular, Mo levels in...
Some regions of Argentina are affected by high concentrations of molybdenum, arsenic and vanadium from natural sources in their groundwater. In particular, Mo levels in groundwater from Eduardo Castex (La Pampa, Argentina) typically exceed the guidelines for drinking water formerly established by WHO at 70 μg/L. Therefore, this study investigated the uptake of Mo in plants, using cress (Lepidium sativum L.) as a model using hydroponic experiments with synthetic solutions and groundwater from La Pampa. Cress grown from control experiments (150 μg/L Mo, pH 7) presented an average Mo concentration of 35.2 mg/kg (dry weight, d.w.), higher than the typical total plant range (0.7-2.5 mg/kg d.w.) in the literature. Using pooled groundwater samples (65.0-92.5 μg/L Mo) from wells of La Pampa (Argentina) as growth solutions resulted in significantly lower cress Mo levels (1.89-4.59 mg/kg d.w.) than were obtained for synthetic solutions of equivalent Mo concentration. This may be due to the high levels in these groundwater samples of As, V, Fe and Mn which are known to be associated with volcanic deposits. This research addressed the hitherto scarcity of data about the effect of various physicochemical parameters on the uptake of Mo in plants.
Topics: Arsenic; Drinking Water; Groundwater; Molybdenum; Water Pollutants, Chemical
PubMed: 33928502
DOI: 10.1007/s11356-021-13902-w -
ACS Biomaterials Science & Engineering Apr 2023Metal-organic frameworks (MOFs) have high potential as nanoplatforms for the storage and delivery of therapeutic gasotransmitters or gas-releasing molecules. The aim of...
Metal-organic frameworks (MOFs) have high potential as nanoplatforms for the storage and delivery of therapeutic gasotransmitters or gas-releasing molecules. The aim of the present study was to open an investigation into the viability of tricarbonyl-pyrazine-molybdenum(0) MOFs as carbon monoxide-releasing materials (CORMAs). A previous investigation found that the reaction of Mo(CO) with excess pyrazine (pyz) in a sealed ampoule gave a mixture comprising a major triclinic phase with pyz-occupied hexagonal channels, formulated as -Mo(CO)(pyz)·1/2pyz (), and a minor dense cubic phase, formulated as -Mo(CO)(pyz) (). In the present work, an open reflux method in toluene has been optimized for the large-scale synthesis of the pure phase. The crystalline solids and were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), FT-IR and FT-Raman spectroscopies, and C{H} cross-polarization (CP) magic-angle spinning (MAS) NMR spectroscopy. The release of CO from the MOFs was studied by the deoxy-myoglobin (deoxy-Mb)/carbonmonoxy-myoglobin (MbCO) UV-vis assay. and release CO upon contact with a physiological buffer in the dark, delivering 0.35 and 0.22 equiv (based on Mo), respectively, after 24 h, with half-lives of 3-4 h. Both materials display high photostability such that the CO-releasing kinetics is not affected by irradiation of the materials with UV light. These materials are attractive as potential CORMAs due to the slow release of a high CO payload. In the solid-state and under open air, underwent almost complete decarbonylation over a period of 4 days, corresponding to a theoretical CO release of 10 mmol per gram of material.
Topics: Metal-Organic Frameworks; Carbon Monoxide; Molybdenum; Myoglobin; Spectroscopy, Fourier Transform Infrared; Pyrazines
PubMed: 36996427
DOI: 10.1021/acsbiomaterials.3c00140 -
Journal of the American Chemical Society Feb 2020A combination of pulsed EPR, CW EPR, and X-ray absorption spectroscopies has been employed to probe the geometric and electronic structure of the periplasmic...
A combination of pulsed EPR, CW EPR, and X-ray absorption spectroscopies has been employed to probe the geometric and electronic structure of the periplasmic molybdenum-dependent methionine sulfoxide reductase (MsrP). O and H pulsed EPR spectra show that the Mo(V) enzyme form does not possess an exchangeable HO/OH ligand bound to Mo as found in the sulfite oxidizing enzymes of the same family. The nature of the unusual CW EPR spectrum has been re-evaluated in light of new data on the MsrP-N45R variant and related small-molecule analogues of the active site. These data point to a novel "thiol-blocked" [(PDT)MoO(S)(thiolate)] structure, which is supported by new EXAFS data. We discuss these new results in the context of ligand-based and metal-based redox chemistry in the enzymatic oxygen atom transfer reaction.
Topics: Electron Spin Resonance Spectroscopy; Ligands; Methionine Sulfoxide Reductases; Molybdenum; Oxidation-Reduction; X-Ray Absorption Spectroscopy
PubMed: 31989824
DOI: 10.1021/jacs.9b11762