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James T. Hollibaugh - One of the best experts on this subject based on the ideXlab platform.
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Transcriptional response of the obligate anaerobe Desulfuribacillus stibiiarsenatis MLFW‐2T to growth on Antimonate and other terminal electron acceptors
Environmental microbiology, 2019Co-Authors: Christopher A. Abin, James T. HollibaughAbstract:Enzymes of the dimethyl sulfoxide reductase (DMSOR) family catalyse two-electron redox reactions pivotal to the dissimilatory metabolism of a variety of organic and inorganic compounds. The draft genome of the obligately anaerobic bacterium Desulfuribacillus stibiiarsenatis MLFW-2T contains 14 genes that are predicted to encode catalytic subunits of DMSOR family enzymes. We quantified transcription of these genes during growth on Antimonate, arsenate, nitrate and selenate, with the goal of identifying the respiratory Antimonate reductase. Transcription of BHU72_10330, BHU72_03635 and BHU72_07355 was enhanced during growth on arsenate, nitrate and selenate, respectively, implicating these genes as encoding the catalytic subunits of a respiratory arsenate reductase (arrA), periplasmic nitrate reductase (napA) and membrane-bound selenate reductase (srdA) respectively. Transcription of BHU72_07145 increased markedly when MLFW-2T was grown on Antimonate, suggesting that this gene encodes the catalytic subunit of a respiratory Antimonate reductase, designated anrA. We also compared the transcriptomes of MLFW-2T during growth on Antimonate and arsenate to examine the broader physiological response of the organism to growth on these substrates. Relative to arsenate, Antimonate was found to induce transcription of genes involved in pathways for dealing with oxidative stress, including those involved in repairing damaged cellular biomolecules and scavenging reactive oxygen species.
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transcriptional response of the obligate anaerobe desulfuribacillus stibiiarsenatis mlfw 2t to growth on Antimonate and other terminal electron acceptors
Environmental Microbiology, 2018Co-Authors: Christopher A. Abin, James T. HollibaughAbstract:Enzymes of the dimethyl sulfoxide reductase (DMSOR) family catalyse two-electron redox reactions pivotal to the dissimilatory metabolism of a variety of organic and inorganic compounds. The draft genome of the obligately anaerobic bacterium Desulfuribacillus stibiiarsenatis MLFW-2T contains 14 genes that are predicted to encode catalytic subunits of DMSOR family enzymes. We quantified transcription of these genes during growth on Antimonate, arsenate, nitrate and selenate, with the goal of identifying the respiratory Antimonate reductase. Transcription of BHU72_10330, BHU72_03635 and BHU72_07355 was enhanced during growth on arsenate, nitrate and selenate, respectively, implicating these genes as encoding the catalytic subunits of a respiratory arsenate reductase (arrA), periplasmic nitrate reductase (napA) and membrane-bound selenate reductase (srdA) respectively. Transcription of BHU72_07145 increased markedly when MLFW-2T was grown on Antimonate, suggesting that this gene encodes the catalytic subunit of a respiratory Antimonate reductase, designated anrA. We also compared the transcriptomes of MLFW-2T during growth on Antimonate and arsenate to examine the broader physiological response of the organism to growth on these substrates. Relative to arsenate, Antimonate was found to induce transcription of genes involved in pathways for dealing with oxidative stress, including those involved in repairing damaged cellular biomolecules and scavenging reactive oxygen species.
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Dissimilatory Antimonate Reduction and Production of Antimony Trioxide Microcrystals by a Novel Microorganism
Environmental science & technology, 2013Co-Authors: Christopher A. Abin, James T. HollibaughAbstract:Antimony (Sb) is a metalloid that has been exploited by humans since the beginning of modern civilization. The importance of Sb to such diverse industries as nanotechnology and health is underscored by the fact that it is currently the ninth-most mined metal worldwide. Although its toxicity mirrors that of its Group 15 neighbor arsenic, its environmental chemistry is very different, and, unlike arsenic, relatively little is known about the fate and transport of Sb, especially with regard to biologically mediated redox reactions. To further our understanding of the interactions between microorganisms and Sb, we have isolated a bacterium that is capable of using Antimonate [Sb(V)] as a terminal electron acceptor for anaerobic respiration, resulting in the precipitation of antimonite [Sb(III)] as microcrystals of antimony trioxide. The bacterium, designated strain MLFW-2, is a sporulating member of a deeply branching lineage within the order Bacillales (phylum Firmicutes). This report provides the first unequivocal evidence that a bacterium is capable of conserving energy for growth and reproduction from the reduction of Antimonate. Moreover, microbiological Antimonate reduction may serve as a novel route for the production of antimony trioxide microcrystals of commercial significance to the nanotechnology industry.
Christopher A. Abin - One of the best experts on this subject based on the ideXlab platform.
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Transcriptional response of the obligate anaerobe Desulfuribacillus stibiiarsenatis MLFW‐2T to growth on Antimonate and other terminal electron acceptors
Environmental microbiology, 2019Co-Authors: Christopher A. Abin, James T. HollibaughAbstract:Enzymes of the dimethyl sulfoxide reductase (DMSOR) family catalyse two-electron redox reactions pivotal to the dissimilatory metabolism of a variety of organic and inorganic compounds. The draft genome of the obligately anaerobic bacterium Desulfuribacillus stibiiarsenatis MLFW-2T contains 14 genes that are predicted to encode catalytic subunits of DMSOR family enzymes. We quantified transcription of these genes during growth on Antimonate, arsenate, nitrate and selenate, with the goal of identifying the respiratory Antimonate reductase. Transcription of BHU72_10330, BHU72_03635 and BHU72_07355 was enhanced during growth on arsenate, nitrate and selenate, respectively, implicating these genes as encoding the catalytic subunits of a respiratory arsenate reductase (arrA), periplasmic nitrate reductase (napA) and membrane-bound selenate reductase (srdA) respectively. Transcription of BHU72_07145 increased markedly when MLFW-2T was grown on Antimonate, suggesting that this gene encodes the catalytic subunit of a respiratory Antimonate reductase, designated anrA. We also compared the transcriptomes of MLFW-2T during growth on Antimonate and arsenate to examine the broader physiological response of the organism to growth on these substrates. Relative to arsenate, Antimonate was found to induce transcription of genes involved in pathways for dealing with oxidative stress, including those involved in repairing damaged cellular biomolecules and scavenging reactive oxygen species.
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transcriptional response of the obligate anaerobe desulfuribacillus stibiiarsenatis mlfw 2t to growth on Antimonate and other terminal electron acceptors
Environmental Microbiology, 2018Co-Authors: Christopher A. Abin, James T. HollibaughAbstract:Enzymes of the dimethyl sulfoxide reductase (DMSOR) family catalyse two-electron redox reactions pivotal to the dissimilatory metabolism of a variety of organic and inorganic compounds. The draft genome of the obligately anaerobic bacterium Desulfuribacillus stibiiarsenatis MLFW-2T contains 14 genes that are predicted to encode catalytic subunits of DMSOR family enzymes. We quantified transcription of these genes during growth on Antimonate, arsenate, nitrate and selenate, with the goal of identifying the respiratory Antimonate reductase. Transcription of BHU72_10330, BHU72_03635 and BHU72_07355 was enhanced during growth on arsenate, nitrate and selenate, respectively, implicating these genes as encoding the catalytic subunits of a respiratory arsenate reductase (arrA), periplasmic nitrate reductase (napA) and membrane-bound selenate reductase (srdA) respectively. Transcription of BHU72_07145 increased markedly when MLFW-2T was grown on Antimonate, suggesting that this gene encodes the catalytic subunit of a respiratory Antimonate reductase, designated anrA. We also compared the transcriptomes of MLFW-2T during growth on Antimonate and arsenate to examine the broader physiological response of the organism to growth on these substrates. Relative to arsenate, Antimonate was found to induce transcription of genes involved in pathways for dealing with oxidative stress, including those involved in repairing damaged cellular biomolecules and scavenging reactive oxygen species.
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Dissimilatory Antimonate Reduction and Production of Antimony Trioxide Microcrystals by a Novel Microorganism
Environmental science & technology, 2013Co-Authors: Christopher A. Abin, James T. HollibaughAbstract:Antimony (Sb) is a metalloid that has been exploited by humans since the beginning of modern civilization. The importance of Sb to such diverse industries as nanotechnology and health is underscored by the fact that it is currently the ninth-most mined metal worldwide. Although its toxicity mirrors that of its Group 15 neighbor arsenic, its environmental chemistry is very different, and, unlike arsenic, relatively little is known about the fate and transport of Sb, especially with regard to biologically mediated redox reactions. To further our understanding of the interactions between microorganisms and Sb, we have isolated a bacterium that is capable of using Antimonate [Sb(V)] as a terminal electron acceptor for anaerobic respiration, resulting in the precipitation of antimonite [Sb(III)] as microcrystals of antimony trioxide. The bacterium, designated strain MLFW-2, is a sporulating member of a deeply branching lineage within the order Bacillales (phylum Firmicutes). This report provides the first unequivocal evidence that a bacterium is capable of conserving energy for growth and reproduction from the reduction of Antimonate. Moreover, microbiological Antimonate reduction may serve as a novel route for the production of antimony trioxide microcrystals of commercial significance to the nanotechnology industry.
J. M. Herrmann - One of the best experts on this subject based on the ideXlab platform.
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Study by electrical conductivity measurement of redox properties of vanadium Antimonate and mixed vanadium and iron Antimonate
Journal of Molecular Catalysis A: Chemical, 2005Co-Authors: J.m.m. Millet, I. C. Marcu, J. M. HerrmannAbstract:he redox properties of vanadium and mixed vanadium and iron have been studied by elec. cond. measurements. The solids which are active catalysts in the ammoxidn. of propane, were shown to be n-type semiconductors with electrons as the main charge carriers. The changes in the elec. cond. during alternative exposures to propane, oxygen and mixts. of propane and oxygen have been studied at 753 K. The pure vanadium Antimonate became a p-type semiconductor after redn. under propane whereas the pure iron Antimonate remained an n-type semiconductor. An intermediate behavior was obsd. for the mixed vanadium and iron compd. The changes in type of elec. cond. have been explained by a surface transformation with the formation of antimony oxide and a rutile-type solid soln. with only cationic vacancies. Such a transformation was limited when iron substitutes vanadium and was absent in pure iron Antimonate.
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Study by electrical conductivity measurement of redox properties of vanadium Antimonate and mixed vanadium and iron Antimonate
Journal of Molecular Catalysis A: Chemical, 2005Co-Authors: Jean-marc M. Millet, I. C. Marcu, J. M. HerrmannAbstract:The redox properties of vanadium and mixed vanadium and iron have been studied by electrical conductivity measurements. The solids which are active catalysts in the ammoxidation of propane, were shown to be n-type semiconductors with electrons as the main charge carriers. The changes in the electrical conductivity during alternative exposures to propane, oxygen and mixtures of propane and oxygen have been studied at 753 K. The pure vanadium Antimonate became a p-type semiconductor after reduction under propane whereas the pure iron Antimonate remained an n-type semiconductor. An intermediate behavior was observed for the mixed vanadium and iron compound. The changes in type of electrical conductivity have been explained by a surface transformation with the formation of antimony oxide and a rutile-type solid solution with only cationic vacancies. Such a transformation was limited when iron substitutes vanadium and was absent in pure iron Antimonate.
Ibrahim M. El-naggar - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamics and ion exchange equilibria of Gd3+, Eu3+ and Ce3+ ions on H+ form of titanium(IV) Antimonate
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002Co-Authors: Essam S. Zakaria, Ismail M. Ali, Ibrahim M. El-naggarAbstract:Abstract Titanium(IV) Antimonate as a cation exchanger has been obtained in amorphous form by mixing titanium tetrachloride to antimony pentachloride in molar ratio of Ti/Sb in the starting solutions is unity. Ion-exchange equilibria of Gd3+, Eu3+ and Ce3+ ions with H+ form of titanium(IV) Antimonate in MCl3–HCl media with a solution ionic strength of 0.1, in the reaction M n+ + R — H ⇌ R — M +n H + has been measured in both forward and reverse reactions at different reaction temperatures 25, 40 and 60 °C (±1 °C) by batch method. The thermodynamic selectivity sequence as a function of X M decrease in the order Gd3+>Eu3+>Ce3+ and this selectivity order is parallel to the equilibrium capacity of rare earth metal ions on H+ form of titanium(IV) Antimonate. On the basis of exchange isotherms, thermodynamic equilibrium constants, and values of ΔG°, ΔH° and ΔS° for exchange of Gd3+/H+, Eu3+/H+ and Ce3+/H+ on titanium(IV) Antimonate have been calculated. Negative values of entropy changes (ΔS°) have been reported for all exchange systems studied (M3+/H+) on the exchange materials of titanium(IV) Antimonate.
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ADSORPTION OF SOME HAZARDOUS RADIONUCLIDES ON CERIUM(IV) Antimonate
Journal of Radioanalytical and Nuclear Chemistry, 1999Co-Authors: H.f. Aly, Essam S. Zakaria, S.a. Shady, Ibrahim M. El-naggarAbstract:Cerium(IV) Antimonate was prepared by dropwise addition of 0.6M antimony pentachloride and 0.6M cerium ammonium nitrate solutions by a molar ratio of Ce/Sb 0.75. Exchange isotherms for H+/Co2+, H+/Cs+, H+/Zn2+, H+/Sr2+ and H+/Eu3+ were determined at 25, 40 and 60°C. Besides, it was proved that europium is physically adsorped, while zinc, strontium, cobalt and cesium are chemically adsorbed. Moreover, the heat of adsorption of zinc, strontium, cobalt and cesium on cerium (IV) Antimonate was calculated and indicated that cerium(IV) Antimonate is of endothermic behavior towards these ions. Also the distribution coefficients of these ions were determined and it was found that the selectivity is in the order: Eu3+>Sr2+>Cs+>Na+.
Essam S. Zakaria - One of the best experts on this subject based on the ideXlab platform.
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Kinetic aspects and swelling changes of magnesium and cerium titano-Antimonates in aqueous and mixed solvents
Journal of colloid and interface science, 2009Co-Authors: Essam S. Zakaria, Ismail M. Ali, Hisham Fouad AlyAbstract:Magnesium titano-Antimonate (MgTi5Sb2O16.-12.5H2O) and cerium titano-Antimonate (Ce(2).(7)Ti5Sb2O19.-15.0H2O) were synthesized as new cation exchangers using the in situ precipitation technique. Physico-chemical investigations showed different behaviors for the obtained materials. The materials have significant stability at high acid concentration and temperature. The ion exchange capacity for Cs+ in the presence of different alcoholic solvents was found to increase and generally obey the order C2H5OH>CH3OH>H2O. Diffusion coefficients (Di) and thermodynamic parameters of Cs+ exchange in both magnesium and cerium titano-Antimonates in aqueous and alcoholic solutions were calculated. The swelling ratios of the materials were predicted by applying modified calculations at constant values of Di. The results showed insignificant swelling behavior in the presence of organic solvents.
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Thermodynamics and ion exchange equilibria of Gd3+, Eu3+ and Ce3+ ions on H+ form of titanium(IV) Antimonate
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2002Co-Authors: Essam S. Zakaria, Ismail M. Ali, Ibrahim M. El-naggarAbstract:Abstract Titanium(IV) Antimonate as a cation exchanger has been obtained in amorphous form by mixing titanium tetrachloride to antimony pentachloride in molar ratio of Ti/Sb in the starting solutions is unity. Ion-exchange equilibria of Gd3+, Eu3+ and Ce3+ ions with H+ form of titanium(IV) Antimonate in MCl3–HCl media with a solution ionic strength of 0.1, in the reaction M n+ + R — H ⇌ R — M +n H + has been measured in both forward and reverse reactions at different reaction temperatures 25, 40 and 60 °C (±1 °C) by batch method. The thermodynamic selectivity sequence as a function of X M decrease in the order Gd3+>Eu3+>Ce3+ and this selectivity order is parallel to the equilibrium capacity of rare earth metal ions on H+ form of titanium(IV) Antimonate. On the basis of exchange isotherms, thermodynamic equilibrium constants, and values of ΔG°, ΔH° and ΔS° for exchange of Gd3+/H+, Eu3+/H+ and Ce3+/H+ on titanium(IV) Antimonate have been calculated. Negative values of entropy changes (ΔS°) have been reported for all exchange systems studied (M3+/H+) on the exchange materials of titanium(IV) Antimonate.
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ADSORPTION OF SOME HAZARDOUS RADIONUCLIDES ON CERIUM(IV) Antimonate
Journal of Radioanalytical and Nuclear Chemistry, 1999Co-Authors: H.f. Aly, Essam S. Zakaria, S.a. Shady, Ibrahim M. El-naggarAbstract:Cerium(IV) Antimonate was prepared by dropwise addition of 0.6M antimony pentachloride and 0.6M cerium ammonium nitrate solutions by a molar ratio of Ce/Sb 0.75. Exchange isotherms for H+/Co2+, H+/Cs+, H+/Zn2+, H+/Sr2+ and H+/Eu3+ were determined at 25, 40 and 60°C. Besides, it was proved that europium is physically adsorped, while zinc, strontium, cobalt and cesium are chemically adsorbed. Moreover, the heat of adsorption of zinc, strontium, cobalt and cesium on cerium (IV) Antimonate was calculated and indicated that cerium(IV) Antimonate is of endothermic behavior towards these ions. Also the distribution coefficients of these ions were determined and it was found that the selectivity is in the order: Eu3+>Sr2+>Cs+>Na+.