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Kenneth M Noll - One of the best experts on this subject based on the ideXlab platform.
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Reconstructed ancestral Myo-inositol-3-phosphate synthases indicate that ancestors of the Thermococcales and Thermotoga species were more thermophilic than their descendants.
PloS one, 2013Co-Authors: Nicholas C. Butzin, Kristen S Swithers, Pascal Lapierre, J Peter Gogarten, Anna G. Green, Kenneth M NollAbstract:The bacterial genomes of Thermotoga species show evidence of significant interdomain horizontal gene transfer from the Archaea. Members of this genus acquired many genes from the Thermococcales, which grow at higher temperatures than Thermotoga species. In order to study the functional history of an interdomain horizontally acquired gene we used ancestral sequence reconstruction to examine the thermal characteristics of reconstructed ancestral proteins of the Thermotoga lineage and its archaeal donors. Several ancestral sequence reconstruction methods were used to determine the possible sequences of the ancestral Thermotoga and Archaea myo-inositol-3-phosphate synthase (MIPS). These sequences were predicted to be more thermostable than the extant proteins using an established sequence composition method. We verified these computational predictions by measuring the activities and thermostabilities of purified proteins from the Thermotoga and the Thermococcales species, and eight ancestral reconstructed proteins. We found that the ancestral proteins from both the archaeal donor and the Thermotoga most recent common ancestor recipient were more thermostable than their descendants. We show that there is a correlation between the thermostability of MIPS protein and the optimal growth temperature (OGT) of its host, which suggests that the OGT of the ancestors of these species of Archaea and the Thermotoga grew at higher OGTs than their descendants.
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Reconstructed Ancestral Myo-Inositol-3-Phosphate Synthases Indicate That Ancestors of the Thermococcales and Thermotoga Species Were More Thermophilic than Their Descendants
2013Co-Authors: Nicholas C. Butzin, Kristen S Swithers, Peter J Gogarten, Pascal Lapierre, Anna G. Green, Kenneth M NollAbstract:The bacterial genomes of Thermotoga species show evidence of significant interdomain horizontal gene transfer from the Archaea. Members of this genus acquired many genes from the Thermococcales, which grow at higher temperatures than Thermotoga species. In order to study the functional history of an interdomain horizontally acquired gene we used ancestral sequence reconstruction to examine the thermal characteristics of reconstructed ancestral proteins of the Thermotoga lineage and its archaeal donors. Several ancestral sequence reconstruction methods were used to determine the possible sequences of the ancestral Thermotoga and Archaea myo-inositol-3-phosphate synthase (MIPS). These sequences were predicted to be more thermostable than the extant proteins using an established sequence composition method. We verified these computational predictions by measuring the activities and thermostabilities of purified proteins from the Thermotoga and the Thermococcales species, and eight ancestral reconstructed proteins. We found that the ancestral proteins from both the archaeal donor and the Thermotoga most recent common ancestor recipient were more thermostable than their descendants. We show that there is a correlation between the thermostability of MIPS protein and the optimal growth temperature (OGT) of its host, which suggests that the OGT of the ancestors of these species of Archae
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Evolution of mal ABC transporter operons in the Thermococcales and Thermotogales
BMC Evolutionary Biology, 2008Co-Authors: Kenneth M Noll, Pascal Lapierre, J Peter Gogarten, Dhaval M NanavatiAbstract:Background The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus . Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry. Results We demonstrate that the two maltose ATP binding cassette (ABC) transporter operons now found in Tc. litoralis and P. furiosus (termed mal and mdx genes, respectively) are not closely related to one another. The Tc. litoralis and P. furiosus mal genes are most closely related to bacterial mal genes while their respective mdx genes are archaeal. The genes of the two mal operons in Tt. maritima are not related to genes in either of these archaeal operons. They are highly similar to one another and belong to a phylogenetic lineage that includes mal genes from the enteric bacteria. A unique domain of the enteric MalF membrane spanning proteins found also in these Thermotogales MalF homologs supports their relatively close relationship with these enteric proteins. Analyses of genome sequence data from other Thermotogales species, Fervidobacterium nodosum , Thermosipho melanesiensis , Thermotoga petrophila , Thermotoga lettingae , and Thermotoga neapolitana , revealed a third apparent mal operon, absent from the published genome sequence of Tt. maritima strain MSB8. This third operon, mal3 , is more closely related to the Thermococcales ' bacteria-derived mal genes than are mal1 and mal2 . F. nodosum , Ts. melanesiensis , and Tt. lettingae have only one of the mal1-mal2 paralogs. The mal2 operon from an unknown species of Thermotoga appears to have been horizontally acquired by a Thermotoga species that had only mal1 . Conclusion These data demonstrate that the Tc. litoralis and P. furiosus mdx maltodextrin transporter operons arose in the Archaea while their mal maltose transporter operons arose in a bacterial lineage, but not the same lineage as the two maltose transporter operons found in the published Tt. maritima genome sequence. These Tt. maritima maltose transporters are phylogenetically and structurally similar to those found in enteric bacteria and the mal2 operon was horizontally transferred within the Thermotoga lineage. Other Thermotogales species have a third mal operon that is more closely related to the bacterial Thermococcales mal operons, but the data do not support a recent horizontal sharing of that operon between these groups.
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evolution of mal abc transporter operons in the Thermococcales and thermotogales
BMC Evolutionary Biology, 2008Co-Authors: Kenneth M Noll, Peter J Gogarten, Pascal Lapierre, Dhaval M NanavatiAbstract:Background The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus. Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry.
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evolution of mal abc transporter operons in the Thermococcales and thermotogales
BMC Evolutionary Biology, 2008Co-Authors: Kenneth M Noll, Peter J Gogarten, Pascal Lapierre, Dhaval M NanavatiAbstract:The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus. Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry. We demonstrate that the two maltose ATP binding cassette (ABC) transporter operons now found in Tc. litoralis and P. furiosus (termed mal and mdx genes, respectively) are not closely related to one another. The Tc. litoralis and P. furiosus mal genes are most closely related to bacterial mal genes while their respective mdx genes are archaeal. The genes of the two mal operons in Tt. maritima are not related to genes in either of these archaeal operons. They are highly similar to one another and belong to a phylogenetic lineage that includes mal genes from the enteric bacteria. A unique domain of the enteric MalF membrane spanning proteins found also in these Thermotogales MalF homologs supports their relatively close relationship with these enteric proteins. Analyses of genome sequence data from other Thermotogales species, Fervidobacterium nodosum, Thermosipho melanesiensis, Thermotoga petrophila, Thermotoga lettingae, and Thermotoga neapolitana, revealed a third apparent mal operon, absent from the published genome sequence of Tt. maritima strain MSB8. This third operon, mal3, is more closely related to the Thermococcales' bacteria-derived mal genes than are mal1 and mal2. F. nodosum, Ts. melanesiensis, and Tt. lettingae have only one of the mal1-mal2 paralogs. The mal2 operon from an unknown species of Thermotoga appears to have been horizontally acquired by a Thermotoga species that had only mal1. These data demonstrate that the Tc. litoralis and P. furiosus mdx maltodextrin transporter operons arose in the Archaea while their mal maltose transporter operons arose in a bacterial lineage, but not the same lineage as the two maltose transporter operons found in the published Tt. maritima genome sequence. These Tt. maritima maltose transporters are phylogenetically and structurally similar to those found in enteric bacteria and the mal2 operon was horizontally transferred within the Thermotoga lineage. Other Thermotogales species have a third mal operon that is more closely related to the bacterial Thermococcales mal operons, but the data do not support a recent horizontal sharing of that operon between these groups.
Mohamed Jebbar - One of the best experts on this subject based on the ideXlab platform.
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molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon thermococcus barophilus
Scientific Reports, 2016Co-Authors: Anaïs Cario, Axel Thiel, Mohamed Jebbar, Nelly Kervarec, Phil M OgerAbstract:The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response.
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restoration of the di myo inositol phosphate pathway in the piezo hyperthermophilic archaeon thermococcus barophilus
Biochimie, 2015Co-Authors: Anaïs Cario, Alex Mizgier, Axel Thiel, Mohamed Jebbar, Phil OgerAbstract:Most Thermococcales accumulate di-myo-inositol-phosphate (DIP) as an organic solute as a response to heat stress. We have studied the accumulation of this osmolyte in the high-hydrostatic pressure adapted hyperthermophile Thermococcus barophilus. We found no accumulation of DIP under any of the stress conditions tested, although this archaeon harbors the 3 DIP synthesis genes. Lack of synthesis is due to the lack of expression of TERMP_01135 coding for the second step of DIP synthesis. In contrast to other species, the T. barophilus synthesis operon is interrupted by a four gene locus, in reverse orientation. Restoring an operon like structure at the DIP locus restored DIP synthesis, but did not have an impact on growth characteristics, suggesting that other mechanisms have evolved in this organism to cope with heat stress.
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Complete Genome Sequence of the Obligate Piezophilic Hyperthermophilic Archaeon Pyrococcus yayanosii CH1
Journal of Bacteriology, 2011Co-Authors: Xu Jun, Mohamed Jebbar, Philippe Oger, Lupeng Liu, Fengping Wang, Xiao XiangAbstract:Pyrococcus yayanosii CH1 is the first obligate piezophilic hyperthermophilic archaeon isolated from the deep-sea hydrothermal site Ashadze on the mid-Atlantic ridge at a depth of 4,100 m. This organism grows within a temperature range of 80 to 108 degrees C and a hydrostatic pressure range of 20 to 120 MPa, with optima at 98 degrees C and 52 MPa, respectively. Here, we report the complete genome sequence (1,716,817 bp, with a G+C content of 51.6%) of the type strain P. yayanosii CH1(T) (= JCM 16557). This genomic information reveals a systematic view of the piezoadaptation strategy and evolution scenario of metabolic pathways in Thermococcales.
Pascal Lapierre - One of the best experts on this subject based on the ideXlab platform.
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Reconstructed ancestral Myo-inositol-3-phosphate synthases indicate that ancestors of the Thermococcales and Thermotoga species were more thermophilic than their descendants.
PloS one, 2013Co-Authors: Nicholas C. Butzin, Kristen S Swithers, Pascal Lapierre, J Peter Gogarten, Anna G. Green, Kenneth M NollAbstract:The bacterial genomes of Thermotoga species show evidence of significant interdomain horizontal gene transfer from the Archaea. Members of this genus acquired many genes from the Thermococcales, which grow at higher temperatures than Thermotoga species. In order to study the functional history of an interdomain horizontally acquired gene we used ancestral sequence reconstruction to examine the thermal characteristics of reconstructed ancestral proteins of the Thermotoga lineage and its archaeal donors. Several ancestral sequence reconstruction methods were used to determine the possible sequences of the ancestral Thermotoga and Archaea myo-inositol-3-phosphate synthase (MIPS). These sequences were predicted to be more thermostable than the extant proteins using an established sequence composition method. We verified these computational predictions by measuring the activities and thermostabilities of purified proteins from the Thermotoga and the Thermococcales species, and eight ancestral reconstructed proteins. We found that the ancestral proteins from both the archaeal donor and the Thermotoga most recent common ancestor recipient were more thermostable than their descendants. We show that there is a correlation between the thermostability of MIPS protein and the optimal growth temperature (OGT) of its host, which suggests that the OGT of the ancestors of these species of Archaea and the Thermotoga grew at higher OGTs than their descendants.
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Reconstructed Ancestral Myo-Inositol-3-Phosphate Synthases Indicate That Ancestors of the Thermococcales and Thermotoga Species Were More Thermophilic than Their Descendants
2013Co-Authors: Nicholas C. Butzin, Kristen S Swithers, Peter J Gogarten, Pascal Lapierre, Anna G. Green, Kenneth M NollAbstract:The bacterial genomes of Thermotoga species show evidence of significant interdomain horizontal gene transfer from the Archaea. Members of this genus acquired many genes from the Thermococcales, which grow at higher temperatures than Thermotoga species. In order to study the functional history of an interdomain horizontally acquired gene we used ancestral sequence reconstruction to examine the thermal characteristics of reconstructed ancestral proteins of the Thermotoga lineage and its archaeal donors. Several ancestral sequence reconstruction methods were used to determine the possible sequences of the ancestral Thermotoga and Archaea myo-inositol-3-phosphate synthase (MIPS). These sequences were predicted to be more thermostable than the extant proteins using an established sequence composition method. We verified these computational predictions by measuring the activities and thermostabilities of purified proteins from the Thermotoga and the Thermococcales species, and eight ancestral reconstructed proteins. We found that the ancestral proteins from both the archaeal donor and the Thermotoga most recent common ancestor recipient were more thermostable than their descendants. We show that there is a correlation between the thermostability of MIPS protein and the optimal growth temperature (OGT) of its host, which suggests that the OGT of the ancestors of these species of Archae
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Evolution of mal ABC transporter operons in the Thermococcales and Thermotogales
BMC Evolutionary Biology, 2008Co-Authors: Kenneth M Noll, Pascal Lapierre, J Peter Gogarten, Dhaval M NanavatiAbstract:Background The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus . Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry. Results We demonstrate that the two maltose ATP binding cassette (ABC) transporter operons now found in Tc. litoralis and P. furiosus (termed mal and mdx genes, respectively) are not closely related to one another. The Tc. litoralis and P. furiosus mal genes are most closely related to bacterial mal genes while their respective mdx genes are archaeal. The genes of the two mal operons in Tt. maritima are not related to genes in either of these archaeal operons. They are highly similar to one another and belong to a phylogenetic lineage that includes mal genes from the enteric bacteria. A unique domain of the enteric MalF membrane spanning proteins found also in these Thermotogales MalF homologs supports their relatively close relationship with these enteric proteins. Analyses of genome sequence data from other Thermotogales species, Fervidobacterium nodosum , Thermosipho melanesiensis , Thermotoga petrophila , Thermotoga lettingae , and Thermotoga neapolitana , revealed a third apparent mal operon, absent from the published genome sequence of Tt. maritima strain MSB8. This third operon, mal3 , is more closely related to the Thermococcales ' bacteria-derived mal genes than are mal1 and mal2 . F. nodosum , Ts. melanesiensis , and Tt. lettingae have only one of the mal1-mal2 paralogs. The mal2 operon from an unknown species of Thermotoga appears to have been horizontally acquired by a Thermotoga species that had only mal1 . Conclusion These data demonstrate that the Tc. litoralis and P. furiosus mdx maltodextrin transporter operons arose in the Archaea while their mal maltose transporter operons arose in a bacterial lineage, but not the same lineage as the two maltose transporter operons found in the published Tt. maritima genome sequence. These Tt. maritima maltose transporters are phylogenetically and structurally similar to those found in enteric bacteria and the mal2 operon was horizontally transferred within the Thermotoga lineage. Other Thermotogales species have a third mal operon that is more closely related to the bacterial Thermococcales mal operons, but the data do not support a recent horizontal sharing of that operon between these groups.
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evolution of mal abc transporter operons in the Thermococcales and thermotogales
BMC Evolutionary Biology, 2008Co-Authors: Kenneth M Noll, Peter J Gogarten, Pascal Lapierre, Dhaval M NanavatiAbstract:Background The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus. Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry.
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evolution of mal abc transporter operons in the Thermococcales and thermotogales
BMC Evolutionary Biology, 2008Co-Authors: Kenneth M Noll, Peter J Gogarten, Pascal Lapierre, Dhaval M NanavatiAbstract:The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus. Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry. We demonstrate that the two maltose ATP binding cassette (ABC) transporter operons now found in Tc. litoralis and P. furiosus (termed mal and mdx genes, respectively) are not closely related to one another. The Tc. litoralis and P. furiosus mal genes are most closely related to bacterial mal genes while their respective mdx genes are archaeal. The genes of the two mal operons in Tt. maritima are not related to genes in either of these archaeal operons. They are highly similar to one another and belong to a phylogenetic lineage that includes mal genes from the enteric bacteria. A unique domain of the enteric MalF membrane spanning proteins found also in these Thermotogales MalF homologs supports their relatively close relationship with these enteric proteins. Analyses of genome sequence data from other Thermotogales species, Fervidobacterium nodosum, Thermosipho melanesiensis, Thermotoga petrophila, Thermotoga lettingae, and Thermotoga neapolitana, revealed a third apparent mal operon, absent from the published genome sequence of Tt. maritima strain MSB8. This third operon, mal3, is more closely related to the Thermococcales' bacteria-derived mal genes than are mal1 and mal2. F. nodosum, Ts. melanesiensis, and Tt. lettingae have only one of the mal1-mal2 paralogs. The mal2 operon from an unknown species of Thermotoga appears to have been horizontally acquired by a Thermotoga species that had only mal1. These data demonstrate that the Tc. litoralis and P. furiosus mdx maltodextrin transporter operons arose in the Archaea while their mal maltose transporter operons arose in a bacterial lineage, but not the same lineage as the two maltose transporter operons found in the published Tt. maritima genome sequence. These Tt. maritima maltose transporters are phylogenetically and structurally similar to those found in enteric bacteria and the mal2 operon was horizontally transferred within the Thermotoga lineage. Other Thermotogales species have a third mal operon that is more closely related to the bacterial Thermococcales mal operons, but the data do not support a recent horizontal sharing of that operon between these groups.
Anaïs Cario - One of the best experts on this subject based on the ideXlab platform.
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molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon thermococcus barophilus
Scientific Reports, 2016Co-Authors: Anaïs Cario, Axel Thiel, Mohamed Jebbar, Nelly Kervarec, Phil M OgerAbstract:The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response.
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restoration of the di myo inositol phosphate pathway in the piezo hyperthermophilic archaeon thermococcus barophilus
Biochimie, 2015Co-Authors: Anaïs Cario, Alex Mizgier, Axel Thiel, Mohamed Jebbar, Phil OgerAbstract:Most Thermococcales accumulate di-myo-inositol-phosphate (DIP) as an organic solute as a response to heat stress. We have studied the accumulation of this osmolyte in the high-hydrostatic pressure adapted hyperthermophile Thermococcus barophilus. We found no accumulation of DIP under any of the stress conditions tested, although this archaeon harbors the 3 DIP synthesis genes. Lack of synthesis is due to the lack of expression of TERMP_01135 coding for the second step of DIP synthesis. In contrast to other species, the T. barophilus synthesis operon is interrupted by a four gene locus, in reverse orientation. Restoring an operon like structure at the DIP locus restored DIP synthesis, but did not have an impact on growth characteristics, suggesting that other mechanisms have evolved in this organism to cope with heat stress.
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high hydrostatic pressure increases amino acid requirements in the piezo hyperthermophilic archaeon thermococcus barophilus
Research in Microbiology, 2015Co-Authors: Anaïs Cario, Florence Lormieres, Xiao Xiang, Philippe OgerAbstract:Abstract We have established a defined growth medium for the piezophilic hyperthermophilic archaeon Thermococcus barophilus , which allows growth yields of ca. 108 cells/ml under both atmospheric and high hydrostatic pressure . Our results demonstrate a major impact of hydrostatic pressure on amino acid metabolism , with increases from 3 amino acids required at atmospheric pressure to 17 at 40 MPa. We observe in T. barophilus and other Thermococcales a similar discrepancy between the presence/absence of amino acid synthesis pathways and amino acid requirements, which supports the existence of alternate, but yet unknown, amino acid synthesis pathways, and may explain the low number of essential amino acids observed in T. barophilus and other Thermococcales. T. barophilus displays a strong metabolic preference for organic polymers such as polypeptides and chitin, which may constitute a more readily available resource of carbon and energy in situ in deep-sea hydrothermal vents. We hypothesize that the low energy yields of fermentation of organic polymers, together with energetic constraints imposed by high hydrostatic pressure, may render de novo synthesis of amino acids ecologically unfavorable. Induction of this metabolic switch to amino acid recycling can explain the requirement for non-essential amino acids by Thermococcales for efficient growth in defined medium.
Patrick Forterre - One of the best experts on this subject based on the ideXlab platform.
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The first stages of greigite mineralization of Thermococcales.
2018Co-Authors: Aurore Gorlas, Patrick Forterre, Pierre Jacquemot, Jean-michel Guigner, Sukhvinder Gill, François GuyotAbstract:(A) Scanning and transmission electron microscopy images of T. prieurii cells incubated for 5 hours; scale bar = 2μm, (B) 24 hours; scale bar = 200nm and (C) 48 hours; scale bar = 100nm with mineralization medium and their respective elemental analyses by EDXS (A(i), B(i), C(i)). Cu and Ni peaks are derived from the supporting grid. For each microscopy images, the black arrow indicates the location of the EDXS analysis. The first minerals formed on the cell surfaces correspond to amorphous Fe(III) phosphates (A, B). The Thermococcales S-layer is the highly reactive interface for iron sequestration (B). After 48 hours of incubation in mineralization medium, Thermococcales cells release extracellular polymeric substances mineralized with amorphous iron phosphates (C).
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Greigite nanocrystals produced by hyperthermophilic archaea of Thermococcales order
2018Co-Authors: Aurore Gorlas, Patrick Forterre, Pierre Jacquemot, Jean-michel Guigner, Sukhvinder Gill, François GuyotAbstract:Interactions between hyperthermophilic archaea and minerals occur in hydrothermal deep-sea vents, one of the most extreme environments for life on Earth. These interactions occur in the internal pores and at surfaces of active hydrothermal chimneys. In this study, we show that, at 85°C, Thermococcales, the predominant hyperthermophilic microorganisms inhabiting hot parts of hydrothermal deep-sea vents, produce greigite nanocrystals (Fe3S4) on extracellular polymeric substances, and that an amorphous iron phosphate acts as a precursor phase. Greigite, although a minor component of chimneys, is a recognized catalyst for CO2 reduction thus implying that Thermococcales may influence the balance of CO2 in hydrothermal ecosystems. We propose that observation of greigite nanocrystals on extracellular polymeric substances could provide a signature of hyperthermophilic life in hydrothermal deep-sea vents.
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The production of greigite by other Thermococcales.
2018Co-Authors: Aurore Gorlas, Patrick Forterre, Pierre Jacquemot, Jean-michel Guigner, Sukhvinder Gill, François GuyotAbstract:(A) Transmission electron microscopy image of T. nautili cells mineralized incubated for 168 hours with mineralization medium. Scale bar = 100nm. (B) Transmission electron microscopy image of T. kodakaraensis cells mineralized incubated for 168 hours with mineralization medium. Scale bar = 500nm. The nanocrystals of greigite are indicated by black arrows.
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The iron sulfide mineralization of Thermococcales cells and vesicles (MVs).
2018Co-Authors: Aurore Gorlas, Patrick Forterre, Pierre Jacquemot, Jean-michel Guigner, Sukhvinder Gill, François GuyotAbstract:(A) Scanning electron microscopy image of T. prieurii cells and vesicles mineralized and organized in aggregates. Every sphere observed can be a mineralized cell (from 0.8 μm to 1.4 μm) or a vesicle (up to 0.5 μm). Scale bar = 1μm. (B)Transmission electron microscopy image of T. prieurii cells and vesicles entirely mineralized incubated for 168 hours with mineralization medium (“a” indicates the location of the EDXS analysis); scale bar = 500nm; (C) and elemental analysis by EDXS; with Fe/S ratio of about 0.5. Cu peaks are derived from the supporting grid. (D) Electron diffraction pattern of the minerals of the cell surfaces and/or filling, corresponding to pyrite. This is a polycrystalline pattern with strong preferred orientations toward a common 2–11 zone axis. (E) Transmission electron microscopy image of numerous extracellular greigite nanocrystals (indicated by black arrows) located near a vesicle containing pyrite (indicated by a red arrow); scale bar = 100nm (F) and near a cell; about fifty nanocrystals were counted to obtain the 30–70 nm range; scale bar = 100nm.
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pTN3-like integrated elements in Thermococcales.
2017Co-Authors: Matteo Cossu, Evelyne Marguet, Patrick Forterre, Catherine Badel, Ryan Catchpole, Danièle Gadelle, Valérie Barbe, Jacques ObertoAbstract:The presence of pTN3-like integrated elements was investigated in all completely sequenced Thermococcales genomes by synteny analysis using the SyntTax web server [42]. In addition to T. nautili, the genomes of T. guaymasensis DSM11113, T. eurythermalis A501, T. kodakarensis KOD1, T. barophilus CH5, and T. cleftensis CL1 carry an extensive genomic region corresponding to plasmid pTN3 shown on top. Each arrow corresponds to an individual gene numbered according to GenBank annotations. The consistent gene color code illustrates orthology across organisms while white color indicates its absence. As indicated by a blue dotted line, conservation of synteny is clearly visible on the right border and limited by the gene encoding pTN3 C-ter integrase and its remnants. Truncated N-terminal-encoding integrase genes constitute pseudogenes lacking a stop codon and are therefore not annotated. Genetic divergence appears stronger on the left border.
