The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Marie Thérèse Giudici-orticoni - One of the best experts on this subject based on the ideXlab platform.
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Hyperthermostable and oxygen resistant hydrogenases from a hyperthermophilic bacterium Aquifex aeolicus: Physicochemical properties
International Journal of Hydrogen Energy, 2006Co-Authors: Marianne Guiral, C. Aubert, P. Tron, V. Belle, Christophe Léger, B. Guigliarelli, Marie Thérèse Giudici-orticoniAbstract:The discovery of hydrogenases in hyperthermophiles has important ramifications not only in microbial physiology and evolution but also in biotechnologies. These organisms are the source of extremely stable enzymes (regarding temperature, pressure, and O2). Aquifex aeolicus is a microaerophilic, hyperthermophilic bacterium containing three [NiFe] hydrogenases. It is the most hyperthermophilic bacterium known to date and grows at 85 ◦ C under a H2/CO2/O2 atmosphere. The Aquificales represent the earliest branching order of the bacterial domain indicating that they are the most ancient bacteria. Two Aquifex hydrogenases (one membrane-bound and one soluble) have been purified and characterized. In contrast to the majority of the [NiFe] hydrogenases, the hydrogenases from A. aeolicus are rather tolerant to oxygen. The molecular basis of the oxygen resistance of Aquifex hydrogenases has been investigated. The great stability of Aquifex hydrogenases with respect to oxygen and high temperatures make these enzymes good candidates for biotechnological uses. 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
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Hyperthermostable and oxygen resistant hydrogenases from a hyperthermophilic bacterium Aquifex aeolicus: physicochemical properties and physiological roles
International Journal of Hydrogen Energy, 2006Co-Authors: Marianne Guiral, C. Aubert, P. Tron, V. Belle, Christophe Léger, B. Guigliarelli, Marie Thérèse Giudici-orticoniAbstract:The discovery of hydrogenases in hyperthermophiles has important ramifications not only in microbial physiology and evolution but also in biotechnologies. These organisms are the source of extremely stable enzymes (regarding temperature, pressure, and O2 ). Aquifex aeolicus is a microaerophilic, hyperthermophilic bacterium containing three [NiFe] hydrogenases. It is the most hyperthermophilic bacterium known to date and grows at 85 °C under a H2/CO2/O2 atmosphere. The Aquificales represent the earliest branching order of the bacterial domain indicating that they are the most ancient bacteria. Two Aquifex hydrogenases (one membrane-bound and one soluble) have been purified and characterized. In contrast to the majority of the [NiFe] hydrogenases, the hydrogenases from A. aeolicus are rather tolerant to oxygen. The molecular basis of the oxygen resistance of Aquifex hydrogenases has been investigated. The great stability of Aquifex hydrogenases with respect to oxygen and high temperatures make these enzymes good candidates for biotechnological uses.
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Hydrogen metabolism in the hyperthermophilic bacterium Aquifex aeolicus
Biochemical Society Transactions, 2005Co-Authors: Marianne Guiral, C. Aubert, Marie Thérèse Giudici-orticoniAbstract:Aquifex aeolicus is a microaerophilic, hydrogen-oxidizing, hyperthermophilic bacterium containing three [NiFe] hydrogenases. Two of these three enzymes (one membrane-bound and one soluble) have been purified and characterized. The Aquifex hydrogenases are thermostable and tolerant to oxygen. A cellular function for the three hydrogenases has been proposed. The two membrane-bound periplasmic hydrogenases may function in energy conservation, whereas the soluble cytoplasmic hydrogenase is probably involved in the CO2 fixation pathway.
Marianne Guiral - One of the best experts on this subject based on the ideXlab platform.
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Hyperthermostable and oxygen resistant hydrogenases from a hyperthermophilic bacterium Aquifex aeolicus: Physicochemical properties
International Journal of Hydrogen Energy, 2006Co-Authors: Marianne Guiral, C. Aubert, P. Tron, V. Belle, Christophe Léger, B. Guigliarelli, Marie Thérèse Giudici-orticoniAbstract:The discovery of hydrogenases in hyperthermophiles has important ramifications not only in microbial physiology and evolution but also in biotechnologies. These organisms are the source of extremely stable enzymes (regarding temperature, pressure, and O2). Aquifex aeolicus is a microaerophilic, hyperthermophilic bacterium containing three [NiFe] hydrogenases. It is the most hyperthermophilic bacterium known to date and grows at 85 ◦ C under a H2/CO2/O2 atmosphere. The Aquificales represent the earliest branching order of the bacterial domain indicating that they are the most ancient bacteria. Two Aquifex hydrogenases (one membrane-bound and one soluble) have been purified and characterized. In contrast to the majority of the [NiFe] hydrogenases, the hydrogenases from A. aeolicus are rather tolerant to oxygen. The molecular basis of the oxygen resistance of Aquifex hydrogenases has been investigated. The great stability of Aquifex hydrogenases with respect to oxygen and high temperatures make these enzymes good candidates for biotechnological uses. 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
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Hyperthermostable and oxygen resistant hydrogenases from a hyperthermophilic bacterium Aquifex aeolicus: physicochemical properties and physiological roles
International Journal of Hydrogen Energy, 2006Co-Authors: Marianne Guiral, C. Aubert, P. Tron, V. Belle, Christophe Léger, B. Guigliarelli, Marie Thérèse Giudici-orticoniAbstract:The discovery of hydrogenases in hyperthermophiles has important ramifications not only in microbial physiology and evolution but also in biotechnologies. These organisms are the source of extremely stable enzymes (regarding temperature, pressure, and O2 ). Aquifex aeolicus is a microaerophilic, hyperthermophilic bacterium containing three [NiFe] hydrogenases. It is the most hyperthermophilic bacterium known to date and grows at 85 °C under a H2/CO2/O2 atmosphere. The Aquificales represent the earliest branching order of the bacterial domain indicating that they are the most ancient bacteria. Two Aquifex hydrogenases (one membrane-bound and one soluble) have been purified and characterized. In contrast to the majority of the [NiFe] hydrogenases, the hydrogenases from A. aeolicus are rather tolerant to oxygen. The molecular basis of the oxygen resistance of Aquifex hydrogenases has been investigated. The great stability of Aquifex hydrogenases with respect to oxygen and high temperatures make these enzymes good candidates for biotechnological uses.
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Hydrogen metabolism in the hyperthermophilic bacterium Aquifex aeolicus
Biochemical Society Transactions, 2005Co-Authors: Marianne Guiral, C. Aubert, Marie Thérèse Giudici-orticoniAbstract:Aquifex aeolicus is a microaerophilic, hydrogen-oxidizing, hyperthermophilic bacterium containing three [NiFe] hydrogenases. Two of these three enzymes (one membrane-bound and one soluble) have been purified and characterized. The Aquifex hydrogenases are thermostable and tolerant to oxygen. A cellular function for the three hydrogenases has been proposed. The two membrane-bound periplasmic hydrogenases may function in energy conservation, whereas the soluble cytoplasmic hydrogenase is probably involved in the CO2 fixation pathway.
Piero Cammarano - One of the best experts on this subject based on the ideXlab platform.
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Sensitivity of ribosomes of the hyperthermophilic bacterium Aquifex pyrophilus to aminoglycoside antibiotics.
Journal of bacteriology, 1996Co-Authors: M Bocchetta, R Huber, Piero CammaranoAbstract:A poly(U)-programmed cell-free system from the hyperthermophilic bacterium Aquifex pyrophilus has been developed, and the susceptibility of Aquifex ribosomes to the miscoding-inducing and inhibitory actions of all known classes of aminoglycoside antibiotics has been assayed at temperatures (75 to 80 degrees C) close to the physiological optimum for cell growth. Unlike Thermotoga maritima ribosomes, which are systematically refractory to all known classes of aminoglycoside compounds (P. Londei, S. Altamura, R. Huber, K. O. Stetter, and P. Cammarano, J. offteriol. 170-4353-4360, 1988), Aquifex ribosomes are susceptible to all of the aminoglycosides tested (disubstituted 2-deoxystreptamines, monosubstituted 2-deoxystreptamines, sand streptidine compounds). The significance of this result in light of the Aquifex and Thermotoga placements in phylogenetic trees of molecular sequences is discussed.
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Arrangement and nucleotide sequence of the gene (fus) encoding elongation factor G (EF-G) from the hyperthermophilic bacterium Aquifex pyrophilus: Phylogenetic depth of hyperthermophilic bacteria inferred from analysis of the EF-G/fus sequences
Journal of molecular evolution, 1995Co-Authors: M Bocchetta, Orsola Tiboni, Anna M. Sanangelantoni, Elena Ceccarelli, Roberta Creti, Piero CammaranoAbstract:The gene fus (for EF-G) of the hyperthermophilic bacterium Aquifex pyrophilus was cloned and sequenced. Unlike the other bacteria, which display the streptomycin-operon arrangement of EF genes (5′-rps12-rps7 fus-tuf-3′), the Aquifex fus gene (700 codons) is not preceded by the two small ribosomal subunit genes although it is still followed by a tuf gene (for EF-Tu). The opposite strand upstream from the EF-G coding locus revealed an open reading frame (ORF) encoding a polypeptide having 52.5% identity with an E. coli protein (the pdxJ gene product) involved in pyridoxine condensation. The Aquifex EF-G was aligned with available homologs representative of Deinococci, high G + C Gram positives, Proteobacteria, cyanobacteria, and several Archaea. Outgroup-rooted phylogenies were constructed from both the amino acid and the DNA sequences using first and second codon positions in the alignments except sites containing synonymous changes. Both datasets and alternative tree-making methods gave a consistent topology, with Aquifex and Thermotoga maritima (a hyperthermophile) as the first and the second deepest offshoots, respectively. However, the robustness of the inferred phylogenies is not impressive. The branching of Aquifex more deeply than Thennotoga and the branching of Thermotoga more deeply than the other taxa examined are given at bootstrap values between 65 and 70% in the fus-based phylogenies, while the EF-G(2)-based phylogenies do not provide a statistically significant level of support (⩽ 50% bootstrap confirmation) for the emergence of Thermotoga between Aquifex and the successive offshoot (Thermus genus). At present, therefore, the placement of Aquifex at the root of the bacterial tree, albeit reproducible, can be asserted only with reservation, while the emergence of Thermotoga between the Aquificales and the Deinococci remains (statistically) indeterminate.
C. Aubert - One of the best experts on this subject based on the ideXlab platform.
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Hyperthermostable and oxygen resistant hydrogenases from a hyperthermophilic bacterium Aquifex aeolicus: Physicochemical properties
International Journal of Hydrogen Energy, 2006Co-Authors: Marianne Guiral, C. Aubert, P. Tron, V. Belle, Christophe Léger, B. Guigliarelli, Marie Thérèse Giudici-orticoniAbstract:The discovery of hydrogenases in hyperthermophiles has important ramifications not only in microbial physiology and evolution but also in biotechnologies. These organisms are the source of extremely stable enzymes (regarding temperature, pressure, and O2). Aquifex aeolicus is a microaerophilic, hyperthermophilic bacterium containing three [NiFe] hydrogenases. It is the most hyperthermophilic bacterium known to date and grows at 85 ◦ C under a H2/CO2/O2 atmosphere. The Aquificales represent the earliest branching order of the bacterial domain indicating that they are the most ancient bacteria. Two Aquifex hydrogenases (one membrane-bound and one soluble) have been purified and characterized. In contrast to the majority of the [NiFe] hydrogenases, the hydrogenases from A. aeolicus are rather tolerant to oxygen. The molecular basis of the oxygen resistance of Aquifex hydrogenases has been investigated. The great stability of Aquifex hydrogenases with respect to oxygen and high temperatures make these enzymes good candidates for biotechnological uses. 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
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Hyperthermostable and oxygen resistant hydrogenases from a hyperthermophilic bacterium Aquifex aeolicus: physicochemical properties and physiological roles
International Journal of Hydrogen Energy, 2006Co-Authors: Marianne Guiral, C. Aubert, P. Tron, V. Belle, Christophe Léger, B. Guigliarelli, Marie Thérèse Giudici-orticoniAbstract:The discovery of hydrogenases in hyperthermophiles has important ramifications not only in microbial physiology and evolution but also in biotechnologies. These organisms are the source of extremely stable enzymes (regarding temperature, pressure, and O2 ). Aquifex aeolicus is a microaerophilic, hyperthermophilic bacterium containing three [NiFe] hydrogenases. It is the most hyperthermophilic bacterium known to date and grows at 85 °C under a H2/CO2/O2 atmosphere. The Aquificales represent the earliest branching order of the bacterial domain indicating that they are the most ancient bacteria. Two Aquifex hydrogenases (one membrane-bound and one soluble) have been purified and characterized. In contrast to the majority of the [NiFe] hydrogenases, the hydrogenases from A. aeolicus are rather tolerant to oxygen. The molecular basis of the oxygen resistance of Aquifex hydrogenases has been investigated. The great stability of Aquifex hydrogenases with respect to oxygen and high temperatures make these enzymes good candidates for biotechnological uses.
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Hydrogen metabolism in the hyperthermophilic bacterium Aquifex aeolicus
Biochemical Society Transactions, 2005Co-Authors: Marianne Guiral, C. Aubert, Marie Thérèse Giudici-orticoniAbstract:Aquifex aeolicus is a microaerophilic, hydrogen-oxidizing, hyperthermophilic bacterium containing three [NiFe] hydrogenases. Two of these three enzymes (one membrane-bound and one soluble) have been purified and characterized. The Aquifex hydrogenases are thermostable and tolerant to oxygen. A cellular function for the three hydrogenases has been proposed. The two membrane-bound periplasmic hydrogenases may function in energy conservation, whereas the soluble cytoplasmic hydrogenase is probably involved in the CO2 fixation pathway.
M Bocchetta - One of the best experts on this subject based on the ideXlab platform.
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Sensitivity of ribosomes of the hyperthermophilic bacterium Aquifex pyrophilus to aminoglycoside antibiotics.
Journal of bacteriology, 1996Co-Authors: M Bocchetta, R Huber, Piero CammaranoAbstract:A poly(U)-programmed cell-free system from the hyperthermophilic bacterium Aquifex pyrophilus has been developed, and the susceptibility of Aquifex ribosomes to the miscoding-inducing and inhibitory actions of all known classes of aminoglycoside antibiotics has been assayed at temperatures (75 to 80 degrees C) close to the physiological optimum for cell growth. Unlike Thermotoga maritima ribosomes, which are systematically refractory to all known classes of aminoglycoside compounds (P. Londei, S. Altamura, R. Huber, K. O. Stetter, and P. Cammarano, J. offteriol. 170-4353-4360, 1988), Aquifex ribosomes are susceptible to all of the aminoglycosides tested (disubstituted 2-deoxystreptamines, monosubstituted 2-deoxystreptamines, sand streptidine compounds). The significance of this result in light of the Aquifex and Thermotoga placements in phylogenetic trees of molecular sequences is discussed.
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Arrangement and nucleotide sequence of the gene (fus) encoding elongation factor G (EF-G) from the hyperthermophilic bacterium Aquifex pyrophilus: Phylogenetic depth of hyperthermophilic bacteria inferred from analysis of the EF-G/fus sequences
Journal of molecular evolution, 1995Co-Authors: M Bocchetta, Orsola Tiboni, Anna M. Sanangelantoni, Elena Ceccarelli, Roberta Creti, Piero CammaranoAbstract:The gene fus (for EF-G) of the hyperthermophilic bacterium Aquifex pyrophilus was cloned and sequenced. Unlike the other bacteria, which display the streptomycin-operon arrangement of EF genes (5′-rps12-rps7 fus-tuf-3′), the Aquifex fus gene (700 codons) is not preceded by the two small ribosomal subunit genes although it is still followed by a tuf gene (for EF-Tu). The opposite strand upstream from the EF-G coding locus revealed an open reading frame (ORF) encoding a polypeptide having 52.5% identity with an E. coli protein (the pdxJ gene product) involved in pyridoxine condensation. The Aquifex EF-G was aligned with available homologs representative of Deinococci, high G + C Gram positives, Proteobacteria, cyanobacteria, and several Archaea. Outgroup-rooted phylogenies were constructed from both the amino acid and the DNA sequences using first and second codon positions in the alignments except sites containing synonymous changes. Both datasets and alternative tree-making methods gave a consistent topology, with Aquifex and Thermotoga maritima (a hyperthermophile) as the first and the second deepest offshoots, respectively. However, the robustness of the inferred phylogenies is not impressive. The branching of Aquifex more deeply than Thennotoga and the branching of Thermotoga more deeply than the other taxa examined are given at bootstrap values between 65 and 70% in the fus-based phylogenies, while the EF-G(2)-based phylogenies do not provide a statistically significant level of support (⩽ 50% bootstrap confirmation) for the emergence of Thermotoga between Aquifex and the successive offshoot (Thermus genus). At present, therefore, the placement of Aquifex at the root of the bacterial tree, albeit reproducible, can be asserted only with reservation, while the emergence of Thermotoga between the Aquificales and the Deinococci remains (statistically) indeterminate.